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800 Garden
Technical Information Report
May 2022 | Master Site Plan TIR Report
May 2022 | Master Site Plan TIR Report
December 2022
800 Garden – Bay West
i
Technical Information Report
May 2022
Prepared for:
Bay West
Prepared by:
KPFF Consulting Engineers
1601 Fifth Avenue, Suite 1600
Seattle, WA 98101
Phone: (206) 622-5822
KPFF Project No. 2000705
FOR REFERENCE ONLY
December 2022
KPFF Consulting Engineers
ii
800 Garden – Bay West
iii
Table of Contents
1. Project Overview ........................................................................................................................................... 1
2. Conditions and Requirements Summary ................................................................................................... 2
Core Requirement No. 1: Discharge at the Natural Location ........................................................................ 2
Core Requirement No. 2: Off-Site Analysis ................................................................................................... 2
Core Requirement No. 3: Flow Control .......................................................................................................... 2
Core Requirement No. 4: Conveyance System ............................................................................................. 3
Core Requirement No. 5: Construction stormwater pollution prevention ...................................................... 3
Core Requirement No. 6: Maintenance and Operations ............................................................................... 3
Core Requirement No. 7: Financial Guarantees and Liability ....................................................................... 3
Core Requirement No. 8: Water Quality facilities .......................................................................................... 3
Core Requirement No. 9: On-Site BMPs ....................................................................................................... 3
Special Requirements ..................................................................................................................................... 4
Special Requirement No. 1: Other Adopted Area-Specific Requirements .............................................. 4
Special Requirement No. 2: Flood Hazard Area Delineation .................................................................. 4
Special Requirement No. 3: Flood Protection Facilities .......................................................................... 4
Special Requirement No. 4: Source Control ........................................................................................... 4
Special Requirement No. 5: Oil Control .................................................................................................. 4
Special Requirement No. 6: Aquifer Protection Area .............................................................................. 4
3. Off-Site Analysis ........................................................................................................................................... 4
Bacteria Problem (Type 1) .............................................................................................................................. 5
Dissolved Oxygen (DO) Problem (Type 2) ..................................................................................................... 5
Temperature Problem (Type 3) ...................................................................................................................... 5
4. Flow Control, LID, and Water Quality Facility Analysis and Design ....................................................... 5
Existing Site Hydrology ................................................................................................................................... 5
Developed Site Hydrology .............................................................................................................................. 5
Performance Standards .................................................................................................................................. 6
Flow Control System ....................................................................................................................................... 6
Water Quality System ..................................................................................................................................... 6
5. Conveyance System Analysis and Design................................................................................................. 6
6. Special Reports and Studies ....................................................................................................................... 6
7. Other Permits ................................................................................................................................................ 7
8. Construction Stormwater Pollution Prevention Plan (CSWPPP) Analysis and Design ........................ 7
Erosion and Sediment Control Plan Analysis and Design .............................................................................. 7
Stormwater Pollution Prevention and Spill Control Plan Design .................................................................... 7
9. Bond Quantities, Facility Summaries, and Declaration of Covenant ...................................................... 7
10. Operations and Maintenance Manual ......................................................................................................... 7
KPFF Consulting Engineers
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List of Figures
Figure 1-1: Vicinity Map (Renton GIS)................................................................................................................. 1
List of Tables
Table 1-1: Summary of Site Areas ...................................................................................................................... 1
Table 7-1: List of Permits ..................................................................................................................................... 7
Appendices
Appendix A – Site Figures
Appendix B – Technical Information Report (TIR) Worksheet
Appendix C – Geotechnical Report
Appendix D – Project Plans
Appendix E - Correspondence
800 Garden – Bay West
1
1. Project Overview
The 800 Garden project is located at 800 Garden Avenue North, Renton, Washington (King County Parcel ID
No. 0823059217). It is bounded by Northeast Eighth Street to the south, Garden Avenue to the west, a
railroad to the east, and a home improvement center to the north, refer to figure 1-1 below for a general site
vicinity map. The proposed project consists of three residential buildings with ground-level retail. Between the
buildings will be pedestrian-oriented plazas with landscaping and concrete paths. Off-site improvements in the
public right-of-way include street widening, concrete curbs, landscaping strips, concrete sidewalks, concrete
driveway, ADA curb ramps, and additional property dedicated to the City of Renton (COR). Refer to Table 1-1
below for a summary of the proposed and existing site areas.
Figure 1-1: Vicinity Map (Renton GIS)
Table 1-1: Summary of Site Areas
LAND COVER EXISTING PROPOSED
Building Area (Square Feet) 157,870 325,170
Impervious Site Area (Square Feet) 328,360 149,704
Pervious Site Area (Square Feet) 45,899 57,255
Total Site Area (Square Feet) 532,129 532,129
Total Impervious Area (Square Feet) 486,230 474,874
Percent Impervious 91.2% 89.2%
KPFF Consulting Engineers
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The site currently contains a one-story commercial building, asphalt parking lot, two driveways, concrete
pedestrian walkways, and landscaping. The existing site is generally flat. There is an existing short retaining
wall along the east side that separates the fire lane from the railroad.
In the existing condition, stormwater from the parking lot sheet flows to catch basins spaced throughout the lot.
These catch basins connect to a system that discharges stormwater to the 72-inch public storm drain in
Garden Avenue. Stormwater from the roof and access drives along the east and south sides of the existing
building are conveyed to the north where stormwater connects with the parking lot drainage and discharges
near the middle of the site.
The proposed development will discharge to the same existing stormwater conveyance systems in Garden
Avenue North. New pollution-generating surfaces will be treated using Best Management Practices (BMPs)
that meet enhanced basic water quality standards.
Refer to Appendix A for Land coverage exhibits, basin exhibits, site exhibits, and Appendix B for the TIR
worksheet.
2. Conditions and Requirements Summary
The proposed redevelopment project results in more than 2,000 square feet but less than 50 acres of new plus
replaced impervious surface; therefore, a “Full Drainage Review” is required per the 2017 City of Renton
Surface Water Design Manual (CORSWDM), Section 1.1.2.4. The following is a summary of how the project
will comply with the nine core requirements and six special requirements.
CORE REQUIREMENT NO. 1: DISCHARGE AT THE NATURAL LOCATION
The Project will generally maintain the existing topography and drainage patterns of the site. Runoff from the
project site will continue to discharge to the existing public stormwater system in Garden Avenue. Stormwater
runoff from the frontage improvements will not be redirected as a result of this project. The on-site drainage
facilities are not anticipated to create a significant adverse impact to downstream properties or drainage
systems.
CORE REQUIREMENT NO. 2: OFF-SITE ANALYSIS
An off-site analysis is included in Section 3 of this report, as required by Section 1.2.2 of the CORSWDM.
CORE REQUIREMENT NO. 3: FLOW CONTROL
The project will continue to discharge directly to Johns Creek via the 72-inch public storm drain in Garden
Avenue adjacent to the site. The site and discharge path are located downstream of the Interstate 405 east
right-of-way. Per Section 1.2.3 and Table 1.2.3.B if the CORSWDM, Johns Creek has been identified as a
major receiving water.
Coordination with the City of Renton, included in Appendix E, has determined that the current conveyance
system has sufficient capacity for the project and there are no erosion concerns with Johns Creek.
Furthermore, the project will be reducing the amount of impervious area draining to Johns Creek; as such, the
project does not anticipate adverse impacts due to the development.
800 Garden – Bay West
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As such, flow control will not be required as part of the proposed development.
CORE REQUIREMENT NO . 4: CONVEYANCE SYSTEM
Proposed conveyance system elements on-site and off-site shall be analyzed, designed, and constructed per
Section 1.2.4 of the CORSWDM. Conveyance system calculations will be provided during construction
document permitting following entitlement.
CORE REQUIREMENT NO. 5: CONSTRUCTION STORMWATER POLLUTION
PREVENTION
Temporary Erosion and Sediment Control (TESC) BMPs will be implemented during construction to prevent
the transport of sediment from the project site to the maximum extent feasible. TESC BMPs are anticipated to
include silt fences, conveyance swales, check dams, a sediment pond with a liner, catch basin inserts,
mulching of exposed areas, dust control, and other measures as necessary. A Construction Stormwater
Pollution Prevention Plan (CSWPPP) will be prepared during construction document permitting following
entitlement.
CORE REQUIREMENT NO. 6: MAINTENANCE AND OPER ATIONS
The owner is responsible for the maintenance and operations of the proposed drainage facilities. A
maintenance and operations manual will be provided during construction document permitting following
entitlement.
CORE REQUIREMENT NO. 7: FINANCIAL GUARANTEES AND LIABILITY
The project will post a construction bond, assignment of funds, or a certified check before a building permit is
issued in accordance with the COR Municipal Code 4-6-030. The applicant will also maintain liability
insurance throughout the duration of construction. A maintenance bond will also be submitted to the COR
before receiving acceptance of any newly constructed on-site private storm drain improvements. Bond
quantities will be provided during construction document permitting following entitlement.
CORE REQUIREMENT NO. 8: WATER QUALITY FACILITIES
The project generates more than 5,000 square feet of pollution-generating impervious surfaces (PGIS) with
greater than 50 percent of the site’s runoff to the water quality facility being from commercial land use;
therefore, Enhanced Basic Water Quality is required per Section 1.2.8.1 of the CORSWDM. The project will
treat runoff from target PGIS using a series of proprietary water quality vaults.
See Section 4 of this report for the project’s water quality system.
CORE REQUIREMENT NO. 9: ON-SITE BMPS
The site is greater than 22,000 square feet; therefore, the project is subject to Large Lot BMP Requirements
per Section 1.2.9.2 of the CORSWDM. On-site BMP requirements may be satisfied through two methods: (1)
application of BMPs to the maximum extent feasible, or (2) complying with the Low-Impact Development (LID)
Performance Standard. The project opts to satisfy Core Requirement No. 9 by applying BMPs to the
maximum extent feasible for all new and replaced impervious surfaces and new pervious surfaces.
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The project will evaluate the feasibility for the specific BMPs during construction document permitting following
entitlement.
Soil amendment will be applied to all new pervious surfaces in accordance with Appendix C.2.13 of the
CORSWDM. Roof downspout connects to the public stormwater system will be via perforated pipe connection
in accordance with Appendix C.2.11 of the CORSWM.
SPECIAL REQUIREMENTS
In addition to the nine core requirements, the project must evaluate compliance with the six special drainage
requirements.
Special Requirement No. 1: Other Adopted Area-Specific Requirements
There are no known adopted area-specific regulations for the site; therefore, Special Requirement No. 1 is not
applicable.
Special Requirement No. 2: Flood Hazard Area Delineation
Per the FEMA Flood Map Service Center, the project does not contain and is not adjacent to a flood hazard
area; therefore, Special Requirement No. 2 is not applicable.
Special Requirement No. 3: Flood Protection Facilities
The project will not rely on existing or proposed flood protection facilities for protection against hazards posed
by erosion or inundation; therefore, Special Requirement No. 3 is not applicable.
Special Requirement No. 4: Source Control
Water quality source controls applicable to this project will be applied in accordance with the King County
Stormwater Pollution Prevention Manual and Renton Municipal Code, Title IV.
See Section 8 of this report for the Construction Stormwater Pollution Prevention Plan Analysis and Design.
Special Requirement No. 5: Oil Control
The site is not considered high use because its anticipated average daily traffic count is less than 100 vehicles
per 1,000 square feet of gross building area; therefore, Special Requirement No. 5 is not applicable.
Special Requirement No. 6: Aquifer Protection Area
The site is not located within the Aquifer Protection Areas; therefore, Special Requirement No. 6 is not
applicable.
3. Off-Site Analysis
Per Section 1.2.2 of the CORSWDM, projects shall perform an off-site analysis to assess potential off-site
drainage and water quality impacts associated with the development of the project site.
Per the exemptions laid out in Section 1.2.2 of the CORSWDM, the project meets criteria 2; the project results
in a net reduction of impervious surface and does not exceed 3/4 acre of new pervious surface and utilizes an
existing connection to discharge to the existing 72-inch storm main. The project does not contain or is located
adjacent to an area identified as being a landslide hazard, steep slope hazard area, or erosion hazard area.
However, the project triggers Core Requirement No. 8 (Water Quality Facilities) – as such, the project will
800 Garden – Bay West
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provide an off-site analysis sufficient to identify and address downstream water quality problems requiring
special attention per Section 1.2.2.1.2 of the CORSWDM.
Per the Washington Department of Ecology (DOE) Water Quality Atlas, Johns Creek has been identified as
Category 5 for temperature, bacteria, and dissolved oxygen.
BACTERIA PROBLEM (TYPE 1)
The project will evaluate treatment methods to be implemented during construction document permitting
following entitlement.
DISSOLVED OXYGEN (DO) PROBLEM (TYPE 2)
The project is not proposing to utilize a wetpool, wetpond, or a wetvault to manage stormwater.
No additional facilities are proposed to address dissolved oxygen.
TEMPERATURE PROBLEM (TYPE 3)
The project is not proposing to utilize a wetpond to provide water quality, and the project is not proposing open
drainage features.
No additional facilities are proposed to address water temperature.
4. Flow Control, LID, and Water Quality Facility Analysis and
Design
EXISTING SITE HYDROLOGY
The project consists of one threshold discharge area; the parking lot and building all drain to the existing 72-
inch storm main under Garden Avenue. Surface stormwater in the parking lot sheet flows to a series of catch
basins spaced throughout the lot. Stormwater is conveyed to the west where it discharges to the public storm
drain. Surface stormwater from the access road along the west, east, and south sides of the building sheet
flows to catch basins, which then conveys stormwater to the southwest corner of the site where stormwater
discharges to the existing public storm drain. Stormwater from the roof connects to the southerly stormwater
system prior to discharging to the public storm main.
Refer to Appendix A for an existing conditions basin exhibit.
DEVELOPED SITE HYDROLOGY
The development will consist of one threshold discharge area made up of three buildings, an access road
along the north and east perimeter of the site, and large pedestrian-oriented plazas between the buildings and
on the southwest corner of the site. Runoff from the PGIS drive aisles around the site will be conveyed to
water quality facilities designed to provide enhanced water quality treatment and sized for all surface areas
draining to the facility.
Refer to Appendix A for a proposed conditions basin exhibit.
KPFF Consulting Engineers
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PERFORMANCE STANDARD S
The project is exempt from flow control as discussed in Section 2, Core Requirement No. 3 of this report.
On-site BMPs will be implemented to the maximum extent feasible per the Large Lot BMP Requirements in
Section 1.2.9.2.2 of the CORSWDM.
The conveyance system will have sufficient capacity to convey and contain the 25-year peak flow per Section
1.2.4 of the CORSWDM.
The project is subject to Enhanced Basic Water Quality per Section 1.2.8.1 of the CORSWDM.
FLOW CONTROL SYSTEM
The project is exempt from flow control as discussed in Section 2, Core Requirement No. 3 of this report.
WATER QUALITY SYSTEM
All new PGIS and surfaces adjacent to and downstream of the PGIS will be directed to a below-grade water
quality vault. The project will evaluate the various emerging stormwater treatment technologies that have
received DOE General Use Level Designation approval for at minimum enhanced water quality treatment. The
facility will be sized to provide treatment for 91 percent of the total PGIS runoff volume to comply with Core
Requirement No. 8.
5. Conveyance System Analysis and Design
No existing capacity issues were found in the off-site analysis as discussed in Section 3 of this report;
therefore, existing off-site conveyance systems are not analyzed. All new on-site and off-site conveyance
system elements shall be analyzed, designed, and constructed per Section 1.2.4.1 of the CORSWDM.
Conveyance system calculations will be provided during construction document permitting following
entitlement.
6. Special Reports and Studies
A Geotechnical Engineering Report has been prepared by GeoEngineers dated March 10, 2022. Refer to
Appendix C for a detailed analysis of the site explorations and existing soils.
800 Garden – Bay West
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7. Other Permits
Section 1.1.3 of the CORSWDM provides other required permits for the project, which are included in the table
below.
Table 7-1: List of Permits
Agency Permit/Approval
Washington State Department of Ecology NPDES Construction Stormwater permit
City of Renton Civil Construction Permit
Clearing, Grading, and Building Permits
8. Construction Stormwater Pollution Prevention Plan
(CSWPPP) Analysis and Design
EROSION AND SEDIMENT CONTROL PLAN ANALYSIS AND DESIGN
Temporary and permanent erosion and sediment control (ESC) measures will be implemented per Section
D.2.1 of the CORSWDM. A CSWPPP will be prepared during construction document permitting following
entitlement.
STORMWATER POLLUTION PREVENTION AND SPILL CONTROL PLAN DESIGN
Stormwater pollution prevention and spill control (SWPPS) measures will be implemented per Section D.2.2 of
the CORSWDM. A CSWPPP will be prepared during construction document permitting following entitlement.
9. Bond Quantities, Facility Summaries, and Declaration of
Covenant
The Site Improvement Bond Quantity Worksheet provided by the Community of Economic Development (CED)
will be prepared during construction document permitting following entitlement.
10. Operations and Maintenance Manual
The stormwater facilities located on-site generally consist of catch basins for collection; storm drainage pipes
for conveyance; infiltrating bioretention planters for water quality treatment; stormwater structures including
manholes, a flow splitter, and a pump; and rock splash pads for outfall protection.
The Maintenance and Operations Manual is intended for the project owner once the project is complete and
will be prepared during construction document permitting following entitlement, in accordance with Appendix A
of the CORSWDM.
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800 Garden – Bay West
Appendix A
Appendix A
Site Figures
CSK-A1 – Existing Drainage Areas
CSK-A2 – Proposed Drainage Areas
CSK-A3 – Existing Drainage Basin
CSK-A4 – Proposed Drainage Basin
CSK-A5 – Off-site Analysis Discharge Map
CSK-A6 – NRCS Soil Map
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NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
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9,028 752
City of Renton Print map Template
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
3/10/2022
Legend
5120256
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
512
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
5' Primary
5' Intermediate
2019.sid
Red: Band_1
Green: Band_2
Blue: Band_3
N I-405DISCHARGE
POINT
PROJECT
SITE
JOHNS CREEK
0.25 MILE
DOWNSTREAM
~0.57 MILE
DOWNSTREAM
GARDEN AVE N
N 8TH ST
LAKE
WASHINGTON
Off-site Analysis Discharge Map
CSK-A5
Soil Map—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/21/2022
Page 1 of 3526040052606005260800526100052612005261400526160052604005260600526080052610005261200526140052616005261800559100559300559500559700559900560100560300560500560700560900561100561300561500
559100 559300 559500 559700 559900 560100 560300 560500 560700 560900 561100 561300 561500
47° 30' 24'' N 122° 13' 0'' W47° 30' 24'' N122° 10' 56'' W47° 29' 37'' N
122° 13' 0'' W47° 29' 37'' N
122° 10' 56'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 300 600 1200 1800
Feet
0 100 200 400 600
Meters
Map Scale: 1:6,980 if printed on B landscape (17" x 11") sheet.
Soil Map may not be valid at this scale.
Project Location
CSK-A6
Soil group "Ur"
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: King County Area, Washington
Survey Area Data: Version 17, Aug 23, 2021
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 6, 2020—Jul 27,
2020
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Soil Map—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/21/2022
Page 2 of 3
CSK-A6
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
AgC Alderwood gravelly sandy
loam, 8 to 15 percent slopes
8.4 1.9%
AkF Alderwood and Kitsap soils,
very steep
36.7 8.2%
InC Indianola loamy sand, 5 to 15
percent slopes
54.1 12.1%
RdC Ragnar-Indianola association,
sloping
25.0 5.6%
RdE Ragnar-Indianola association,
moderately steep
10.9 2.4%
Ur Urban land 279.0 62.4%
Totals for Area of Interest 447.1 100.0%
Soil Map—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/21/2022
Page 3 of 3
CSK-A6
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
____________________________________________________________________________________ Signed/Date
800 Garden – Bay West
Appendix B
Appendix B
Technical Information Report (TIR) Worksheet
CITY OF RENTON SURFACE WATER DESIGN MANUAL
2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1
REFERENCE 8-A
TECHNICAL INFORMATION REPORT (TIR)
WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner _____________________________
Phone ___________________________________
Address __________________________________
_________________________________________
Project Engineer ___________________________
Company _________________________________
Phone ___________________________________
Project Name __________________________
CED Permit # ________________________
Location Township ________________
Range __________________
Section _________________
Site Address __________________________
_____________________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Land Use (e.g., Subdivision / Short Subd.)
Building (e.g., M/F / Commercial / SFR)
Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline Management
Structural Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
(check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
____________________________________
__________________
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
____________________________________
__________________
Bay West Development
1725 South Bascin Ave, Suite 1050
Campbell, CA 95008
Thaddeus Egging
KPFF Consulting Engineers
206-622-5822
408-781-0561
800 Garden
23 north
5 east
8
800 Garden Avenue North
Renton, WA 98057
ü
ü
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Blanket
Description: (include conditions in TIR Section 2)
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Approved Adjustment No. ______________________ Date of Approval: _______________________
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
_________________________________________
_________________________________________
Re: SWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan: ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: _____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
_______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
_____________________________________
N/A
N/A
Johns Creek
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3
Part 10 SOILS
Soil Type
______________________
______________________
______________________
______________________
Slopes
________________________
________________________
________________________
________________________
Erosion Potential
_________________________
_________________________
_________________________
_________________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
On-site BMPs: _______________________________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
Ur - Urban Land ~0%-4%Uncategorized
1
1
Direct Discharge
TBD by Contractor
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
(commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
Will be provided at constructiondocument permitting
Will be provided at
constructiondocument permitting
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Control Pollutants
Protect Existing and Proposed BMPs/Facilities
Maintain Protective BMPs / Manage Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore
operation of BMPs/Facilities as necessary
Flag limits of sensitive areas and open space
preservation areas
Other _______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Type/Description Water Quality Type/Description
Detention
Infiltration
Regional Facility
Shared Facility
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
Vegetated Flowpath
Wetpool
Filtration
Oil Control
Spill Control
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
________________
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ____________________________
Cast in Place Vault
Retaining Wall
Rockery > 4′ High
Structural on Steep Slope
Other _______________________________
Will be provided at construction document permitting
800 Garden – Bay West
Appendix C
Appendix C
Geotechnical Report
Geotechnical Engineering Services
800 Garden Mixed-Use
800 Garden Avenue North
Renton, Washington
for
Bay West Development Holdings, LLC
March 10, 2022
Geotechnical Engineering Services
800 Garden Mixed-Use
800 Garden Avenue North
Renton, Washington
for
Bay West Development Holdings, LLC
March 10, 2022
GeoEngineers, Inc.
Redmond, Washington 98052
425.861.6000
Geotechnical Engineering Services
800 Garden Mixed-Use
800 Garden Avenue North
Renton, Washington
File No. 24939-001-00
March 10, 2022
Prepared for:
Bay West Development Holdings, LLC
1725 S. Bascom Avenue, Suite 1050
Campbell, California 95008
Attention: Pete Beritzhoff
Prepared by:
GeoEngineers, Inc.
17425 NE Union Hill Road, Suite 250
Redmond, Washington 98052
425.861.6000
Corey A. Hamil, PE Kyle M. Smith, PE
Geotechnical Engineer Senior Geotechnical Engineer
Robert C. Metcalfe, PE, LEG
Principal
CAH:KMS:RCM:nld
Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy
of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record.
March 10, 2022 | Page i File No. 24939-001-00
1.0 INTRODUCTION ......................................................................................................................................... 1
2.0 PROJECT DESCRIPTION ............................................................................................................................ 1
3.0 FIELD EXPLORATIONS AND LABORATORY TESTING .............................................................................. 1
3.1. Field Explorations ................................................................................................................................... 1
3.2. Laboratory Testing ................................................................................................................................. 1
3.3. Previous Geotechnical Studies ............................................................................................................. 1
4.0 SITE CONDITIONS ...................................................................................................................................... 2
4.1. Site Geology ........................................................................................................................................... 2
4.2. Surface Conditions................................................................................................................................. 2
4.3. Subsurface Soil Conditions ................................................................................................................... 2
4.4. Groundwater Conditions ........................................................................................................................ 3
5.0 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................. 3
5.1. Earthquake Engineering ........................................................................................................................ 4
5.1.1. Site-Specific Response Spectrum ............................................................................................. 4
5.1.2. Seismic Hazards ......................................................................................................................... 5
5.2. Building Foundations ............................................................................................................................. 6
5.2.1. Augercast Piles ........................................................................................................................... 6
5.3. Footing Drains ........................................................................................................................................ 9
5.4. Floor Slabs .............................................................................................................................................. 9
5.4.1. Design Features ...................................................................................................................... 10
5.5. Methane Collection ............................................................................................................................. 10
5.5.1. Methane Barrier ...................................................................................................................... 10
5.5.2. Vent Pipe System .................................................................................................................. 11dr
5.6. Underslab Utility Support .................................................................................................................... 11
5.7. Hardscape and Utilities ...................................................................................................................... 11
5.8. Earthwork ............................................................................................................................................ 12
5.8.1. Clearing and Site Preparation ................................................................................................. 12
5.8.2. Subgrade Preparation ............................................................................................................. 12
5.8.3. Subgrade Protection ................................................................................................................ 13
5.8.4. Structural Fill............................................................................................................................ 13
5.8.5. Temporary Cut Slopes ............................................................................................................. 16
5.8.6. Erosion and Sediment Control ................................................................................................ 16
5.8.7. Utility Trenches ........................................................................................................................ 17
5.9. Pavement Recommendations ............................................................................................................ 17
5.9.1. Subgrade Preparation ............................................................................................................. 17
5.9.2. New Hot Mix Asphalt Pavement ............................................................................................. 17
5.9.3. Portland Cement Concrete Pavement .................................................................................... 17
5.9.4. Asphalt-Treated Base .............................................................................................................. 18
5.10. Construction Dewatering .................................................................................................................... 18
5.11. Infiltration Considerations .................................................................................................................. 19
6.0 RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES .................................................................. 19
7.0 LIMITATIONS ........................................................................................................................................... 19
8.0 REFERENCES .......................................................................................................................................... 20
March 10, 2022 | Page ii File No. 24939-001-00
LIST OF FIGURES
Figure 1. Vicinity Map
Figure 2. Site Plan
Figure 3. Bearing Soils Contour Map
Figure 4. Cross Section A-A’
Figure 5. Cross Section B-B’
Figure 6. Cross Section C-C’
Figure 7. Wall Drainage and Backfill
Figure 8. Compaction Criteria for Trench Backfill
Figure 9. Recommended Site-Specific MCER Response Spectrum
APPENDICES
Appendix A. Field Explorations
Figure A-1 – Key to Exploration Logs
Figures A-2 through A-5 – Log of Borings
Figure A-6 through A-13 – CPT Logs
Appendix B. Laboratory Testing
Figure B-1 – Atterberg Limits Test Results
Appendix C. Boring Logs from Previous Studies
Appendix D. Report Limitations and Guidelines for Use
March 10, 2022 | Page 1 File No. 24939-001-00
1.0 INTRODUCTION
This geotechnical engineering report presents the preliminary results of GeoEngineers’ geotechnical
engineering services for the 800 Garden Mixed-Use development located at 800 Garden Avenue North in
Renton, Washington. The site consists of approximately 11.5 acres (King County Parcel No. 082305-9217)
and is located northeast of the Garden Avenue North and North 8th Street intersection. The site is currently
occupied by a Fry’s Electronics warehouse building and at-grade asphalt paved surface parking lots. The
site is shown relative to surrounding physical features on Figure 1, Vicinity Map and Figure 2, Site Plan.
The purpose of this report is to provide geotechnical engineering conclusions and recommendations for the
design of the planned 800 Garden Mixed-use development. GeoEngineers’ geotechnical engineering
services have been completed in general accordance with our signed agreement executed on
January 8, 2021.
2.0 PROJECT DESCRIPTION
Based on our review of the Pre-Application Submittal, dated November 11, 2021, we understand Bay West
Development is planning a new development that includes demolition of the Fry’s Electronics building and
construction of three new buildings to be completed in three phases. Phase 1 or Building A consists of five
stories of Type III-A timber construction over three levels of Type 1-A concrete construction. Phases 2 and
3, Buildings B and C, respectively, are planned to consist of five stories of Type III-A timber construction
over two levels of Type 1-A concrete construction. The upper five stories of each building phase are planned
to be residential housing consisting of a total of 1,223 units for the three phases. The project also includes
commercial and retail space for two stories of each phased building located along Garden Avenue.
Additional associated improvements include sidewalks, court yards, underground utilities, and landscaping.
3.0 FIELD EXPLORATIONS AND LABORATORY TESTING
3.1. Field Explorations
Subsurface explorations at the site were evaluated by drilling four borings (B-1 through B-4) to depths of
about 75 feet below existing grade and conducting eight cone penetration tests (CPT-1 through CPT-8) to
depths ranging from approximately 41 to 92 feet below existing site grades. The CPTs were advanced to
practical refusal. The approximate locations of the borings and CPTs are shown on Figure 2. Descriptions
of the field exploration program and summary boring and CPT logs are presented in Appendix A.
3.2. Laboratory Testing
Soil samples were obtained during drilling and were taken to GeoEngineers’ laboratory for further
evaluation. Selected samples were tested for the determination of moisture content, fines content and
Atterberg limits. A description of the laboratory testing program and the test results are presented in
Appendix B.
3.3. Previous Geotechnical Studies
We reviewed available geotechnical reports prepared previously by GeoEngineers and others that included
subsurface information at the site or in the immediate vicinity of the site. These documents included
March 10, 2022 | Page 2 File No. 24939-001-00
previous borings logs and laboratory testing for the existing Fry’s Electronics site and for the adjacent
property to the north at the Lowe’s Renton site. The approximate locations of the previous boring logs we
reviewed are shown in Figure 2, and are included in Appendix C.
4.0 SITE CONDITIONS
4.1. Site Geology
We reviewed the geologic map of the Renton Quadrangle (Mullineaux 1965) and a U.S. Geological
Survey Map titled “Geologic Map of Surficial Deposits in the Seattle 30’x60’ Quadrangle, Washington”
(Youd et. Al. 1993). The surficial soils in the vicinity of the site are mapped as modified land over alluvial
deposits. The modified land consists of land changes by man for construction or development purposes,
generally fill methods. The alluvial deposits range from clay to gravel, with silt and fine sand most common
along the Duwamish River floodplain. The alluvium is commonly organic rich, sometimes containing
interbedded peat. The alluvial soils were deposited by the meandering Cedar River and are poorly to
moderately consolidated.
4.2. Surface Conditions
The site is currently occupied by the existing 152,000 square foot Fry’s Electronics warehouse building,
which consists of a single-story prefabricated steel building. The existing Fry’s Electronics warehouse
building is supported on deep foundations (augercast piles). Associated features include an asphalt paved
surface parking lot to the north of the Fry’s Electronics building, access drive lanes, concrete curbing and
landscaping. Site grades range from approximately Elevation 31 to 36 feet from west to east.
Numerous underground utilities are located at the site including sanitary sewer, storm drain, gas, water,
power, and telecommunications fiber, among others.
4.3. Subsurface Soil Conditions
GeoEngineers’ understanding of subsurface conditions is based on the results of our exploration program,
our review of existing geotechnical information, and our review of the geologic map. .
The soils encountered at the site consist of relatively shallow fill overlying alluvial deposits as shown in
Figures 4 through 6, Cross Sections A-A’ through C-C’, respectively, and the boring logs presented in
Appendix A.
Soils encountered at the site generally consisted of the following:
■ Asphalt: Most of the site to the north of and around the Fry’s Electronics building consists of asphalt
pavement. The asphalt pavement was observed to range from approximately 3 to 11 inches thick.
■ Fill: Fill was encountered below the asphalt pavement in each of the borings and CPTs. The fill generally
consisted of soft/loose to medium stiff/medium dense silt and silty sand with variable gravel content.
The thickness of fill encountered in our explorations ranged from approximately 8 to 11 feet.
March 10, 2022 | Page 3 File No. 24939-001-00
■ Alluvium:
Upper Alluvium
The upper alluvial deposits were encountered below the fill in the borings and the cone penetration
test probes. The upper alluvial deposits consist of interbedded layers of sand, silt, clay, and peat
and organic silt. The upper alluvium deposit extends to depths ranging from 39 to 68 feet below
existing site grades (Elevation -3 to -36 feet). The sand layers contain variable amounts of silt and
are the most prevalent unit within the deposit. The sand layers are loose to medium dense, making
them susceptible to liquefaction. Peat and organic silt layers within the upper alluvium vary from
3 to 15 feet thick and are highly compressible, and are generally thickest in the upper portion of
the deposit. Layers of peat and organic silt are present through this deposit. The silt and clay layers
are soft to medium stiff, moderately compressible, and are generally present near the bottom of
this deposit.
Lower Alluvium
The lower alluvium deposits generally consist of medium dense to very dense sand and gravel with
variable silt content. The lower alluvium deposits are considered to be generally consolidated and
a suitable bearing layer for support of building foundations. The top of the lower alluvium deposit
was encountered at depths ranging from 39 to 68 feet below existing site grades (Elevation -3
to -36 feet). Our interpretation of the top of the lower alluvium deposit across the site is shown on
Figure 3, Bearing Soils Contour Map.
4.4. Groundwater Conditions
Based on conditions observed during drilling, the groundwater level at the site ranges from approximately
7½ to 10 feet deep below existing grade, which corresponds to approximately Elevations 26.5 to 24 feet
(North American Vertical Datum of 1988 [NAVD 88]). Groundwater observations are presented on the
exploration logs in Appendix A at the respective depths. Our groundwater observations are consistent with
previous groundwater observations and measurements taken at and in the project site vicinity.
Groundwater observations represent conditions observed during exploration and may not represent the
groundwater conditions throughout the year. Groundwater seepage is expected to fluctuate as a result of
season, precipitation and other factors (i.e. Lake Washington water levels).
5.0 CONCLUSIONS AND RECOMMENDATIONS
A summary of the geotechnical considerations is provided below. The summary is presented for introductory
purposes only and should be used in conjunction with the complete recommendations presented in this
report.
■ The site is designated as seismic Site Class F per the International Building Code (IBC) due to the
presence of potentially liquefiable soils below the building footprints. As a result, a site-specific seismic
response spectrum is required for building periods greater than 0.5 seconds. We recommend that the
building be designed using the recommended risk-targeted maximum-considered earthquake (MCER)
site-specific response spectrum presented in Table 2 and Figure 9.
■ The results of our liquefaction analyses indicate that fill and loose to medium dense alluvial soils,
below the groundwater table, are susceptible to liquefaction during the building code-prescribed
March 10, 2022 | Page 4 File No. 24939-001-00
maximum-considered earthquake (MCE) event (i.e. earthquake event with 2,500-year return period).
Based on the results of our liquefaction-induced settlement analysis, we estimate that free field ground
surface settlement on the order of 2 to 10 inches could occur during an MCE-level earthquake due to
soil liquefaction.
■ Foundation support for the proposed buildings can be provided by augercast piles embedded in the
lower alluvial deposits. The estimated post-construction static foundation settlement of augercast piles
constructed as recommended in this report, is estimated to be less than 1 inch.
■ Design of the at-grade slabs should consider estimate site settlement because of the underlying upper
alluvial deposits; therefore, we recommend that the floor slabs be pile supported. In addition to being
susceptible to liquefaction, the upper alluvial soils are compressible and are expected to settle under
new/increased loading conditions. Static settlements will depend on the thickness of new fill placed in
the building footprints. If slab areas are not supported on deep foundations, long-term static settlement
is anticipated to be 4 to 6 inches. The at-grade floor slab for the building should be underlain by at least
6 inches of clean crushed rock for uniform support and as a capillary break.
■ Imported gravel borrow should be used as structural fill under all building elements.
■ We recommend that perimeter footing drains be installed around the exterior of each building. The
perimeter drains should be installed at the base of the perimeter footings.
■ At-grade pavement areas may be supported on existing soils provided that the upper 2 feet of subgrade
soils are removed, replaced in lifts, and compacted (if possible) to at least 95 percent of the maximum
dry density (MDD) per ASTM International (ASTM) D 1557.
■ On-site fine-grained fill and alluvial soils should not be considered for reuse as structural fill and should
be exported, unless used in landscape areas.
Our specific geotechnical recommendations are presented in the following sections of this report.
5.1. Earthquake Engineering
We evaluated the site for seismic hazards including liquefaction, lateral spreading and fault rupture.
5.1.1. Site-Specific Response Spectrum
A site-specific response analysis was previously completed for the nearby Top Golf site located at 8th and
Logan Avenue. A comparison of the subsurface soil conditions supports the use of the same site-specific
MCER response spectrum for the 800 Garden Avenue site. The site-specific response spectrum is
appropriate for building periods up to 1 second. Buildings with fundamental building periods greater than
1 second will require that a separate site-specific response analysis be completed at this site.
The site-specific response analysis was completed in accordance with the procedure outlined in Chapter 21
of the American Society of Civil Engineers (ASCE) 7-10 code to develop the site-specific MCER response
spectrum. The recommended MCER site-specific response spectrum is presented in Figure 9 and is defined
in Table 1. The design spectrum is taken as two thirds of the MCER values presented in Table 1 per
ASCE 7-10 Section 21.3.
March 10, 2022 | Page 5 File No. 24939-001-00
TABLE 1. IBC SEISMIC PARAMETERS
Period (s) MCER Response Spectrum (g)
0.01 0.45
0.05 0.71
0.075 0.79
0.10 0.86
0.20 1.04
0.30 1.04
0.40 1.04
0.50 1.04
0.75 1.04
1.00 1.04
5.1.2. Seismic Hazards
5.1.2.1. Surface Fault Rupture
The site is located about 2.4 miles south of the Seattle Fault zone. Based on the distance from mapped
known faults, it is our opinion there is a low risk of faut rupture at the site.
5.1.2.2. Liquefaction
Liquefaction refers to a condition in which vibration or shaking of the ground, usually from earthquake
forces, results in development of high excess pore water pressures in saturated soils and subsequent loss
of stiffness and/or strength in the deposit of soil so affected. In general, soils that are susceptible to
liquefaction include loose to medium dense, clean to silty sands and low-plasticity silts that are below the
water table. Ground settlement, lateral spreading and/or sand boils may result from soil liquefaction.
Structures, such as buildings, supported on or within liquefied soils may experience foundation settlement
or lateral movement that can be damaging.
The evaluation of liquefaction potential is a complex procedure and is dependent on numerous site
parameters, including soil grain size, soil density, site geometry, static stress, and the design ground
acceleration. Typically, the liquefaction potential of a site is evaluated by comparing the cyclic stress ratio
(CSR), which is the ratio of the cyclic shear stress induced by an earthquake to the initial effective
overburden stress, to the cyclic resistance ratio (CRR), which is the soils resistance to liquefaction.
We evaluated the liquefaction triggering potential (Youd and Idriss 2001, Idriss and Boulanger 2014,
NCEER 1998 with Cetin correction factor) and liquefaction-induced settlement (Tokimatsu and Seed 1987;
Ishihara and Yoshimine 1992; Idriss and Boulanger 2008) for soil conditions in each of the borings and
CPTs we completed at the site.
Based on our analyses, the potential exists for liquefaction with the sandy and low plasticity silt alluvial
deposits encountered in explorations completed at the site. The cohesive soils encountered within the
alluvium soils may also experience loss of shear strength during seismic loading. Ground settlement
resulting from earthquake-induced liquefaction is estimated to be on the order of 2 to 10 inches, with the
differential settlement between column footings equal to the total estimated settlement.
March 10, 2022 | Page 6 File No. 24939-001-00
5.1.2.3. Lateral Spreading
Lateral spreading involves lateral displacements of large volumes of liquefied soils. Lateral spreading can
occur on near-level ground as blocks of surface soils are displaced relative to adjacent blocks. Lateral
spreading also occurs as blocks of surface soils are displaced toward a nearby slope or free-face such as
a nearby waterfront or stream bank by movement of the underlying liquefied soil. Due to the distance to a
nearby free face and the relatively flat grade, it is our opinion the risk of lateral spreading is low.
5.2. Building Foundations
Based on the presence of the compressible peat and organic silt layers within the upper alluvium, as well
as the presence of potentially liquefiable soils, we recommend that the buildings be supported on deep
foundations consisting of augercast piles. Specific design and construction recommendations for augercast
piles are presented in the following sections.
5.2.1. Augercast Piles
Augercast piles are constructed using a continuous-flight, hollow-stem auger attached to a set of leads
supported by a crane or installed with a fixed-mast drill rig. The first step in the pile casing process consists
of drilling the auger into the ground to the specified tip elevation of the pile. Grout is then pumped through
the hollow-stem during steady withdrawal of the auger, replacing the soils on the flights of the auger. The
final step is to install a steel reinforcing cage and typically a center bar into the column of fresh grout. One
benefit of using augercast piles is that the auger provides support for the soils during the pile installation
process, thus eliminating the need for temporary casing or drilling fluid.
5.2.1.1. Construction Considerations
The augercast piles should be installed using a continuous-flight, hollow-stem auger. As is standard
practice, the pile grout must be pumped under pressure through the hollow stem as the auger is withdrawn.
Maintenance of adequate grout pressure at the auger tip is critical to reduce the potential for encroachment
of adjacent native soils into the grout column. The rate of withdrawal of the auger must remain constant
throughout the installation of the piles to reduce the potential for necking of the piles. Failure to maintain
a constant rate of withdrawal of the auger should result in immediate rejection of that pile. Reinforcing
steel for bending and uplift should be placed in the fresh grout column as soon as possible after withdrawal
of the auger. Centering devices should be used to provide concrete cover around the reinforcing steel.
The contractor should adhere to a waiting period of at least 12 hours between the installation of piles
spaced closer than 8 feet, center-to-center. This waiting period is necessary to avoid disturbing the curing
concrete in previously cast piles.
Grout pumps must be fitted with a volume-measuring device and pressure gauge so that the volume of the
grout placed in each pile and the pressure head maintained during pumping can be observed. A minimum
grout line pressure of 100 pounds per square inch (psi) should be maintained. The rate of auger withdrawal
should be controlled during grouting such that the volume of the grout pumped is equal to at least
115 percent of the theoretical pile volume. A minimum head of 10 feet of grout should be maintained above
the auger tip during withdrawal of the auger to maintain a full column of grout and to prevent hole collapse.
The geotechnical engineer of record should observe drilling operations, monitor grout injection procedures,
record the volume of grout placed in each pile relative to the calculated volume of the hole and evaluate
the adequacy of individual pile installations.
March 10, 2022 | Page 7 File No. 24939-001-00
5.2.1.2. Axial Capacity
Axial pile load capacity in compression is developed from end bearing in the lower alluvial deposits and
from side frictional resistance along the length of the pile. Uplift pile capacity will also be developed from
side frictional resistance along the length of the pile.
The depth to the competent lower alluvial soils varies below the proposed buildings, generally increasing in
depth from east to west across the site. We recommend that pile lengths be determined based on the
minimum required embedment depth in the lower alluvium to achieve the required pile capacity. On the
west side of the site, where the lower alluvium is deeper, the piles will be longer and will consequently
develop more side friction resistance in the thicker deposits of upper alluvium below the peat deposits. The
allowable seismic capacities include the effects of downdrag and the residual strength of potentially
liquefiable layers within the fill and upper alluvial deposits located below the groundwater table.
For planning purposes, we recommend that the site be split into east and west areas. For this preliminary
design purposes, the east and west areas are represented by the areas of the site that are east and west
of the Cross Section A-A’ location (see Figure 4). Augercast pile capacities were developed based on
embedment depths below the lower alluvium contact at Elevation -10 feet for the east area and Elevation
-20 feet for the west area.
Axial pile capacities are presented in Tables 2 and 3, for 18- and 24-inch-diameter augercast piles having
10 and 20 feet of embedment into the lower alluvial deposits. The bearing surface elevation contours for
the lower alluvium is presented in Figure 3. Pile capacities for embedment depths between 10 and 20 feet
can be linearly interpolated between the capacities presented in Tables 2 and 3.
TABLE 2. ALLOWABLE AXIAL PILE CAPACITY – 18-INCH AUGERCAST PILES
Location
Lower
Alluvium
Elevation
(feet)
Embedment
Depth/Minimum
Pile Tip
Elevation (feet)
Static Capacity (kips) Seismic Capacity (kips)
Downward Uplift Downward Uplift
East -10 10 ft (El -20 ft) 105 130 270 100
East -10 20 ft (El -30 ft) 190 190 420 200
West -20 10 ft (El -30 ft) 170 175 315 115
West -20 20 ft (El -40 ft) 260 245 480 240
TABLE 3. ALLOWABLE AXIAL PILE CAPACITY – 24-INCH AUGERCAST PILES
Location
Lower
Alluvium
Elevation
(feet)
Embedment
Depth/Minimum
Pile Tip
Elevation (feet)
Static Capacity (kips) Seismic Capacity (kips)
Downward Uplift Downward Uplift
East -10 10 ft (El -20 ft) 195 175 455 130
East -10 20 ft (El -30 ft) 315 250 675 275
West -20 10 ft (El -30 ft) 290 235 530 155
West -20 20 ft (El -40 ft) 420 325 770 320
March 10, 2022 | Page 8 File No. 24939-001-00
Allowable pile capacities were evaluated based on Allowable Stress Design (ASD) and are for combined
dead plus long-term live loads. The allowable capacities are based on the strength of the supporting soils
and include a factor of safety of 2 for end bearing and side friction and a factor of safety of 1.1 for seismic
conditions. The capacities apply to single piles. If piles are spaced at least three pile diameters on center,
as recommended, no reduction of axial capacity for group action is needed, in our opinion.
The structural characteristics of pile materials and structural connections may impose limitations on pile
capacities and should be evaluated by the structural engineer. For example, steel reinforcing will be needed
for augercast piles subjected to uplift or large bending moments.
5.2.1.3. Lateral Capacity
Lateral loads can be resisted by passive soil pressures on the vertical piles and by the passive soil pressures
on the pile cap. Because of the potential separation between the pile-supported foundation components
and the underlying soil from settlement, base friction along the bottom of the pile cap should not be
included in the calculations for lateral capacity.
Table 4 summarizes the design parameters for laterally loaded piles. We recommend that these parameters
be incorporated into the commercial software LPILE to evaluate response and capacity of piles subject to
lateral loading. For potentially liquefiable soils, a reduced p-multiplier should be applied to the model P-Y
curve of the relevant soil units for evaluating seismic conditions (Boulanger, et al. 2003).
TABLE 4. LPILE SOIL PARAMETERS
Soil Unit1
Approximate Depth Below
Existing Grade (feet) Effective
Unit
Weight
(pcf)
Friction
Angle
(degrees)
Stiffness
Parameter,
k (pci) P- Multiplier1
Top of Soil
Layer
Bottom of
Soil Layer
Fill (Above Groundwater
Table) 0 9 120 34 110
Fill (Below Groundwater
Table) 4 9 57.6 34 70
Upper Loose/Soft to
Medium Dense/Medium
Stiff Alluvium
9 63 57.6 31 50 1 (static) 0.1
(seismic)
Lower Dense to Very
Dense/Hard Alluvium 63 200 67.6 38 120 1 (static) 0.1
(seismic)
Notes:
1 Sand (Reese) Model
pcf – pounds per cubic foot
pci – pounds per cubic inch
Piles spaced closer than five pile diameters apart will experience group effects that will result in a lower
lateral load capacity for trailing rows of piles with respect to leading rows of piles for an equivalent
deflection. We recommend that the lateral load capacity for piles in a pile group spaced less than five pile
diameters apart be reduced in accordance with the factors in Table 5 per AASHTO Load and Resistance
Factor Design (LRFD) Bridge Design Specifications Section 10.7.2.4.
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TABLE 5. PILE P-MULTIPLIERS, PM, FOR MULTIPLE ROW SHADING
Pile Spacing1
(in terms of pile diameter)
P-Multipliers, Pm2, 3
Row 1
(leading row)
Row 2
(1st trailing row)
Row 3 and higher
(2nd trailing row)
3D 0.80 0.40 0.30
5D 1.00 0.85 0.70
Notes:
1. The P-multipliers in the table above are a function of the center to center spacing of piles in the group in the direction of loading
expressed in multiples of the pile diameter, D.
2. The values of Pm were developed for vertical piles only per 2017 ASHTO LRFD Table 10.7.4-1.
3. The P-multipliers are dependent on the pile spacing and the row number in the direction of the loading to establish values of Pm for
other pile spacing values, interpolation between values should be conducted.
We recommend that the passive soil pressure acting on the pile cap be estimated using an equivalent fluid
density of 350 pounds per cubic foot (pcf) where the soil adjacent to the foundation consists of adequately
compacted structural fill. The passive resistance value includes a factor of safety of 1.5 and assumes a
minimum lateral deflection of 1 inch to fully develop the passive resistance. Deflections that are less than
1 inch will not fully mobilize the passive resistance in the soil.
5.2.1.4. Pile Settlement
We estimate that the post-construction settlement of pile foundations, designed and installed as
recommended, will be on the order of 1 inch or less. Maximum differential settlement should be less than
about one-half the post construction settlement. Most of this settlement will occur rapidly as loads are
applied.
5.3. Footing Drains
We recommend that perimeter footing drains be installed around each building. The perimeter drains
should be installed at the base of the exterior footings as shown on Figure 7. The perimeter drains should
be provided with cleanouts and should consist of at least 4-inch-diameter perforated pipe placed on a
3-inch bed of, and surrounded by, 6 inches of drainage material enclosed in a non-woven geotextile fabric
such as Mirafi 140N (or approved equivalent) to prevent fine soil from migrating into the drain material. We
recommend against using flexible tubing for footing drainpipes. The perimeter drains should be sloped to
drain by gravity, if practicable, to a suitable discharge point, preferably a storm drain. We recommend that
the cleanouts be covered and be placed in flush mounted utility boxes. Water collected in roof downspout
lines must not be routed to the footing drain lines.
5.4. Floor Slabs
Given that augercast piles is the recommended foundation support option, we recommend that the floor
slabs be structurally supported on piles because of the estimated total and differential settlement under
static and seismic loading. Since the slab will be pile-supported, the slab subgrade will only need to be
prepared in a manner to facilitate construction and no specific requirements for soft soil removal and/or
compaction below the lower level slabs are required.
However, we recommend that concrete slabs-on-grade be constructed on a gravel layer to provide uniform
support and drainage, and to act as a capillary break as shown in Figure 7.
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5.4.1. Design Features
We recommend that the floor slabs be underlain by a capillary break gravel layer consisting of at least
6 inches of clean crushed gravel meeting the requirements of Section 9-03.1(4)C, Grading No. 67 of the
2020 Washington State Department of Transportation (WSDOT) Standard Specifications. The gravel layer
should be placed directly over the prepared subgrade.
If water vapor migration through the slabs is objectionable, the gravel should be covered with a heavy
plastic sheet, such as 10-mil plastic sheeting, to act as a vapor retarder. This will be necessary in occupied
spaces and where the slabs will be surfaced with tile or will be carpeted. It may also be prudent to apply a
sealer to the slab to further retard the migration of moisture through the floor. The contractor should be
made responsible for maintaining the integrity of the vapor retarder during construction.
5.5. Methane Collection
Provisions should be made under the floor slab to vent potential accumulations of methane gas generated
by decomposition of the peat and other underlying organic soils. We recommend placing a perforated pipe
within a gravel layer and venting the pipes outside the building. Methane vapor mitigation should also
include placing a 30-mil polyvinyl chloride (PVC) geomembrane beneath the floor slab to act as a methane
and water vapor barrier.
5.5.1. Methane Barrier
We recommend that the methane barrier consist of a 30-mil PVC geomembrane liner. The geomembrane
should be installed by an approved and experienced contractor. All seams and penetrations must be
sealed/welded in accordance with the manufacturer’s recommendations. All tears or punctures must be
repaired in accordance with the manufacturers’ requirements. Equipment traffic and foot traffic on top of
the installed barrier must be kept to a minimum. A cushion geotextile may also be used to protect the
barrier from necessary traffic. Also, the contractor must not drive any form stakes through the barrier or
otherwise damage the barrier during construction.
The geomembrane should be installed in such a manner as to provide an impermeable seal at all pipe
penetrations or discontinuities, such as interior and exterior foundations, grade beams, column risers and
utility pipes which penetrate the barrier. On subgrade surfaces, all sharp points and projections must be
removed to limit rips, tears, and punctures of the geomembrane. If damage is identified during
geomembrane installation, it must be repaired immediately. The geomembrane installation must be
constructed in accordance with the manufacturer’s recommendations.
Geomembrane integrity testing should also be completed in accordance with the manufacturer/installer
approved quality assurance manual. Where punctures, tears and/or unsatisfactory welded seams are
identified, appropriate repairs should be made until no evidence of potential leaks are detected. These
repairs should be documented and approved by the owner’s representative. The engineer should observe
the installer’s QA/QC program during construction.
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5.5.2. Vent Pipe System
For planning purposes, we recommend a perforated vent pipe be installed within 10 feet of the inner
perimeter of the building footprints. The perforated pipes should be placed within a 6-inch layer of clean
crushed gravel with negligible sand or silt in conformance with Section 9-03.1(4)C, Grading No. 67 of the
2020 WSDOT Standard Specifications. The pipes should be backfilled as described in the “Underslab Utility
Support” section.
The perforated pipes should consist of 4-inch-diameter, machine slotted PVC pipe, or an approved equal.
Solid wall (blank) PVC pipe should be used in below-grade pipe runs that extend outside the building
footprint.
The horizontal pipe runs should continue to vertical riser pipes placed beyond the exterior building walls to
vent vapors to the atmosphere. The vertical riser pipe should be vented such that precipitation cannot enter
the pipe,
5.6. Underslab Utility Support
We recommend that the floor slab will be structurally supported, as described previously. To mitigate the
potential for damage to utilities below the slab resulting from settlement of the underlying soils, we
recommend that underslab utilities be structurally suspended from the slab. Pea gravel should be placed
as backfill above the underslab utilities in order to reduce the soil loads acting on the suspended utilities.
The pea gravel is anticipated to flow around the suspended utilities as settlement occurs. GeoEngineers
can be consulted to provide estimates of loads acting on the suspended utilities once the details regarding
the depth and size of utilities are known. Alternatively to backfilling with pea gravel, the underslab utilities
can be installed without backfilling such that they are surrounded by a void space. Even with this alternative,
the utilities need to structurally suspended from the slab.
Flexible connections should be provided for all utilities that transition from the pile supported buildings to
surrounding areas. Surrounding areas without a net grade increase should be expected to settle on the
order of 8 to 12 inches over a design life of 50 years from secondary compression in peat and organic soils.
5.7. Hardscape and Utilities
Concrete hardscape areas, such as entry slabs and sidewalks, and utilities on the outside of the buildings
may experience long-term settlement after a design seismic event or as the organic soils compress.
If finished grades are raised by more than about 1 to 2 feet relative to existing grades, long-term settlement
due to consolidation settlement may also occur.
Sidewalks along the building should be detached so that the side closest to the building does not hang up
on the pile-supported structure and cause sidewalks to tilt. Entries should be designed as a ramp with one
end supported on the building and the other end supported on the ground to avoid the development of
abrupt changes in grade. Sidewalks and entry slabs should be underlain by a minimum 4-inch-thick layer
of crushed surfacing base course (CSBC).
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5.8. Earthwork
Based on the subsurface conditions observed in the borings and CPTs, we expect that the soils at the site
may be excavated using conventional heavy-duty construction equipment. Near surface site soils (fill
material) generally consist of loose to medium dense sand and gravel with variable silt and medium stiff to
very stiff silt.
5.8.1. Clearing and Site Preparation
Construction of the proposed buildings and site improvements will require demolition of the existing
Fry’s Electronics building and removal of the existing asphalt surface, walkways, concrete curbing, etc.
Asphalt and concrete may be recycled and reused as structural fill in limited areas outside the building
footprints; otherwise, it should be removed from the site along with other construction debris. The recycled
concrete should be reused as described in the section of this report titled “Reuse of Existing Asphalt,
Basecourse and Concrete Rubble.” All existing utilities should be removed from the building footprints and
rerouted if needed.
Areas to receive fill, structures, or pavements should be cleared of vegetation and stripped of topsoil, if any.
Clearing should consist of removal of all debris, trees, brush and other vegetation within the designated
clearing limits. The topsoil materials could be separated and stockpiled for use in areas to be landscaped.
Debris should be removed from the site, but organic materials could be chipped/composted and also
reused in landscape areas, if desired.
We anticipate that the depth of stripping will range from 4 to 6 inches in landscape areas located on the
site. Actual stripping depths should be determined based on field observations at the time of construction.
The organic soils can be stockpiled and used later for landscaping purposes or may be spread over
disturbed areas following completion of grading. Materials that cannot be used for landscaping or
protection of disturbed areas should be removed from the project site.
Grubbing should consist of removing and disposal of stumps, roots larger than 1-inch-diameter, and matted
roots from the designated grubbing areas. Grubbed materials should be completely removed from the
project site. All depressions made during the grubbing activities to remove stumps and other materials,
should be completely backfilled with properly placed and compacted structural fill. GeoEngineers should
evaluate the exposed soil after completion of stripping and grubbing is completed to confirm suitability prior
to site development.
Care must be taken to minimize softening of subgrade soils during stripping operations. Areas of the
exposed subgrade which become disturbed should be compacted to a firm, non-yielding condition, if
practical, prior to placing any structural fill necessary to achieve design grades. If this is not practical
because the material is too wet, the disturbed material must be aerated and recompacted or excavated
and replaced with structural fill.
5.8.2. Subgrade Preparation
Prior to placing new fills and pavement or hardscape base course materials subgrade areas should be proof
rolled to locate soft or pumping soils. Prior to proof rolling, unsuitable soils should be removed from below
building and pavement/hardscape areas. Proof rolling can be completed using a piece of heavy tire-
mounted equipment such as a loaded dump truck. During wet weather, the exposed subgrade areas should
March 10, 2022 | Page 13 File No. 24939-001-00
be probed to determine the extent of soft soils. If soft or pumping soils are observed, they should be
removed and replaced with structural fill.
If deep pockets of soft silt or pumping soils are encountered outside the building footprints, it may be
possible to limit the depth of overexcavation by placing a woven geotextile fabric such as Mirafi 600X (or
similar material) on the overexcavated subgrade prior to placing structural fill. The geotextile will provide
additional support by bridging over the soft material and will help reduce fines contamination into the
structural fill. This may be performed under pavement areas depending on actual conditions observed
during construction, but it is not necessary under the planned buildings.
After completing the proof-rolling, the subgrade areas should be recompacted to a firm and unyielding
condition, if possible. The achievable degree of compaction will depend on when construction is performed.
If the work is performed during dry weather conditions, we recommend that all subgrade areas be
recompacted to at least 95 percent of the MDD in accordance with the American Society for Testing and
Materials (ASTM) D 1557 test procedure (modified proctor). If the work is performed during wet weather
conditions, it may not be possible to recompact the subgrade to 95 percent of the MDD. In this case, we
recommend that the subgrade be compacted to the extent possible without causing undue heaving or
pumping of the subgrade soils.
Subgrade disturbance or deterioration could occur if the subgrade is wet and cannot be dried. If the
subgrade deteriorates during proof rolling or compaction, it may become necessary to modify the proof
rolling or compaction criteria or methods.
5.8.3. Subgrade Protection
Site soils may contain significant fines content (silt/clay) and will be highly sensitive and susceptible to
moisture and equipment loads. The contractor should take necessary measures to prevent site subgrade
soils from becoming disturbed or unstable and maintain as much of the existing pavement as practicable.
Construction traffic during the wet season should be restricted to specific areas of the site, preferably areas
that are surfaced with crushed rock materials or areas with existing pavement which are not susceptible to
wet weather disturbance.
5.8.4. Structural Fill
All fill, whether on-site soils or imported fill for support of foundations, floor slab areas, pavement areas
and as backfill for retaining walls or in utility trenches should meet the criteria for structural fill presented
below. Structural fill soils should be free of organic matter, debris, man-made contaminants, and other
deleterious materials, with no individual particles larger than 4 inches in greatest dimension. The suitability
of soil for use as structural fill depends on its gradation and moisture content.
5.8.4.1. Materials
Recommended structural fill material quality varies depending upon its use as described below:
■ Structural fill to construct pavement areas, to place below floor slabs, to construct embankments, to
backfill retaining walls and utility trenches, and to place against pile caps should consist of gravel
borrow as described in Section 09-03.12(1) of the 2020 WSDOT Standard Specifications, with the
additional restriction that the fines content be limited to no more than 5 percent, especially if the work
occurs in wet weather or during the wet season (October through May).
March 10, 2022 | Page 14 File No. 24939-001-00
■ Structural fill placed around footing drains should consist of washed ⅜-inch to No. 8 pea gravel per
Section 9-03.1(4)C Grading No. 8, or conform to Section 9-03.12(4) of the 2020 WSDOT Standard
Specifications, as shown on Figure 7.
■ Structural fill placed as CSBC below pavements should conform to Section 9-03.9(3) of the 2020
WSDOT Standard Specifications.
■ Structural fill placed as capillary break below slabs should consist of 1-inch minus clean crushed gravel
with negligible sand or silt in conformance with Section 9-03.1(4)C, Grading No. 67 of the 2020 WSDOT
Standard Specifications, as shown on Figure 7.
We recommend that the suitability of structural fill soil from proposed borrow sources be evaluated by a
representative of our firm before the earthwork contractor begins transporting the soil to the site.
5.8.4.2. Reuse of On-site Soils
The on-site fill is generally fine-grained and has natural moisture contents above typical optimum moisture
content for these soil types, and it will be difficult to achieve the minimum compaction requirements without
drying the soils significantly during the summer months. In our opinion, the on-site soils should not be
planned for use as structural fill. The fine-grained upper alluvial soils (silt) are not suitable for reuse as
structural fill and should be disposed of off-site. Imported gravel borrow should be used for structural fill
and backfilling throughout the site. The on-site fill may be reused in landscape areas outside the building
footprint; however, grading should be planned during the normally dry season (June through September).
The contractor should plan to cover all fill stockpiles with plastic sheeting if it will be used as structural fill.
The reuse of on-site soils is highly dependent on the skill of the contractor, schedule, and the weather, and
we will work with the design team to maximize the reuse of on-site soils outside the building footprint.
5.8.4.3. Reuse of Existing Asphalt, Basecourse and Concrete Rubble
Existing asphalt pavement and Portland cement concrete (PCC) rubble may be reused as structural fill if
properly crushed during demolition. Recycled PCC rubble and base course materials may be reused as
structural fill throughout the project, including under the building footprints. Recycled asphalt may be used
under new pavement and in utility trenches but should not be used under foundations or below the
buildings. Recycled asphalt and concrete should not be used in landscape areas. Location-specific
restrictions on use of recycled materials may apply, therefore we recommend checking with local permit
authorities before planning to use recycled materials.
For use as general structural fill, the asphalt and concrete rubble should be crushed or otherwise ground
up and should meet gradation requirements for gravel borrow as described in Section 9-03.14(1) of the
2020 WSDOT Standard Specifications. If recycled asphalt and/or concrete will be used under pavement
areas, we recommend that it meet gradation requirements for CSBC as described in Section 9-03.9(3) of
the 2020 WSDOT Standard Specifications.
5.8.4.4. Fill Placement and Compaction Criteria
Structural fill should be mechanically compacted to a firm, non-yielding condition. Structural fill should be
placed in loose lifts not exceeding 12 inches in thickness when using heavy compaction equipment and
not more than 6 inches when using hand operated compaction equipment. The actual thickness will be
dependent on the structural fill material used and the type and size of compaction equipment. Each lift
should be moisture conditioned to within about 2 percent of the optimum moisture content and compacted
March 10, 2022 | Page 15 File No. 24939-001-00
to the specified density before placing subsequent lifts. Compaction of all structural fill should be in
accordance with the ASTM D 1557 test method. Structural fill should be compacted to the following criteria:
■ Structural fill in new pavement and hardscape areas outside the City right of way including utility trench
backfill, should be compacted to at least 90 percent of the MDD, except that the upper 2 feet of fill
below final subgrade should be compacted to at least 95 percent of the MDD, as shown in Figure 8.
■ Structural fill placed within the City right of way, including fill for mass grading and utility trench backfill,
should be compacted to at least 95 percent of the MDD or as required by the City.
■ Structural fill placed below floor slabs should be compacted to at least 95 percent of the MDD, including
backfill for utility trenches below the building footprint.
■ Structural fill placed as crushed rock base course below pavements and hardscape should be
compacted to at least 95 percent of the MDD.
■ Non-structural fill, such as fill placed in landscape areas, should be compacted to at least 90 percent
of the MDD, unless otherwise specified by the landscape architect.
5.8.4.5. Weather Considerations
Disturbance of near surface soils should be expected if earthwork is completed during periods of wet
weather. During dry weather, the soils will: (1) be less susceptible to disturbance, (2) provide better
support for construction equipment, and (3) be more likely to meet the required compaction and subgrade
preparation criteria.
The wet weather season generally begins in October and continues through May in western Washington;
however, periods of wet weather may occur during any month of the year. For earthwork activities during
wet weather, we recommend that the following steps be taken:
■ The ground surface in and around the work area should be sloped so that surface water is directed
away from the work area. The ground surface should be graded so that areas of ponded water do not
develop. Measures should be taken by the contractor to prevent surface water from collecting in
excavations and trenches. Measures should be implemented to remove surface water from the work
area, and it should not be directed towards downslope structures, unless properly collected and
conveyed to appropriate catch basins.
■ Earthwork activities should not take place during periods of moderate to heavy precipitation.
■ Slopes with exposed soils should be covered with plastic sheeting.
■ The contractor should take necessary measures to prevent on-site soils and soils to be used as fill from
becoming wet or unstable. These measures may include temporary construction dewatering, the use
of plastic sheeting, sumps with pumps, and grading. The site soils should not be left uncompacted and
exposed to moisture. Sealing the surficial soils by rolling with a smooth-drum roller prior to periods of
precipitation will help reduce the extent that these soils become wet or unstable.
■ The contractor should cover all soil stockpiles that will be used as structural fill with plastic sheeting.
■ Construction traffic should be restricted to specific areas of the site, preferably areas that are surfaced
with working pad materials not susceptible to wet weather disturbance.
March 10, 2022 | Page 16 File No. 24939-001-00
■ Construction activities should be scheduled so that the length of time that soils are left exposed to
moisture is reduced to the extent practical.
Routing of equipment on the existing fill during the wet weather months will be difficult and the subgrade
will likely become highly disturbed and rutted. In addition, a significant amount of mud can be produced by
routing equipment directly on the on-site soils in wet weather. Therefore, to protect the subgrade soils and
to provide an adequate wet weather working surface for the contractor’s equipment and labor, we
recommend that the contractor protect exposed subgrade soils with a crushed gravel working pad at least
12 inches thick underlain by a geotextile separator where needed.
5.8.5. Temporary Cut Slopes
For planning purposes, temporary unsupported cut slopes more than 4 feet high may be inclined 1½H:1V
(horizontal to vertical) in the fill and upper alluvial soils. This temporary cut slope inclination may need to
be flattened by the contractor if significant caving/sloughing or groundwater seepage occurs. For open cuts
at the site, we recommend that:
■ No traffic, construction equipment, stockpiles, or building supplies be allowed at the top of the cut
slopes within a distance of at least 5 feet from the top of the cut;
■ The excavation does not encroach on a 1H:1V influence line projected down from the edges of nearby
or planned foundation elements;
■ Exposed soil along the slope be protected from surface erosion using waterproof tarps or plastic
sheeting or flash coating with shotcrete;
■ Construction activities be scheduled so the length of time the temporary cut is left open is reduced to
the extent practicable;
■ Erosion control measures be implemented as appropriate such that runoff from the site is reduced to
the extent practicable;
■ Surface water be diverted away from the excavation; and
■ The general condition of the slopes be observed periodically by GeoEngineers to confirm adequate
stability.
Because the contractor has control of the construction operations, the contractor should be made
responsible for the stability of the cut slopes, as well as the safety of the excavations. Temporary slopes
must conform to applicable local, state and federal safety regulations.
5.8.6. Erosion and Sediment Control
Construction activities including stripping and grading will expose soils to the erosional effects of wind and
water. The amount and potential impacts of erosion are partly related to the time of year that construction
actually occurs. Wet weather construction will increase the amount and extent of erosion and potential
sedimentation. We recommend maintaining existing vegetation during the wet season, if possible, to
reduce potential erosion.
Erosion and sedimentation control measures may be implemented by using a combination of interceptor
swales, straw bale barriers, silt fences and straw mulch for temporary erosion protection of exposed soils.
March 10, 2022 | Page 17 File No. 24939-001-00
All disturbed areas should be finished graded and paved or landscaped as soon as practicable to reduce
the risk of erosion.
5.8.7. Utility Trenches
Trench excavation, pipe bedding and trench backfilling should be completed using the general procedures
described in the 2020 WSDOT Standard Specifications, or City of Renton requirements, or as specified by
the project civil engineer.
Utility trench backfill should consist of structural fill and should be placed in lifts of 12 inches or less (loose
thickness) when using heavy compaction equipment, and 6 inches or less when using hand compaction
equipment, such that adequate compaction can be achieved through the lift. Each lift must be compacted
prior to placing the subsequent lift. Prior to compaction, the backfill should be moisture conditioned to
within 2 percent of the optimum moisture content. The backfill should be compacted in accordance with
the criteria discussed above. General utility trench backfill recommendations are provided in Figure 8.
5.9. Pavement Recommendations
5.9.1. Subgrade Preparation
We recommend the subgrade soils in new pavement areas be prepared and evaluated as described in the
“Subgrade Preparation” section of this report. All new pavement and hardscape areas should be supported
on subgrade soils that have been proof rolled or probed, and approved by the geotechnical engineer. If the
exposed subgrade soils are loose or soft, it may be necessary to excavate localized areas and replace them
with structural fill or gravel base course. Pavement subgrade conditions should be observed during
construction and prior to placing the base course materials in order to evaluate the presence of zones of
unsuitable subgrade soils and the need for over-excavation and replacement of these zones.
5.9.2. New Hot Mix Asphalt Pavement
In light-duty pavement areas (e.g., automobile parking), we recommend a pavement section consisting of
at least a 3-inch thickness of ½-inch hot-mix asphalt (HMA) per WSDOT Sections 5-04 and 9-03, over a
4-inch thickness of densely compacted CSBC per WSDOT Section 9-03.9(3). In heavy-duty pavement areas
(such as driveways, truck traffic lanes, materials delivery), we recommend a pavement section consisting
of at least a 4-inch thickness of ½-inch HMA over a 6-inch thickness of densely compacted CSBC.
The base course should be compacted to at least 95 percent of the MDD obtained using ASTM D 1557.
We recommend that proof rolling of the subgrade and compacted base course be observed by a
representative from our firm prior to paving. Soft or yielding zones observed during proof rolling may require
overexcavation and replacement with compacted structural fill.
The pavement sections recommended above are based on our experience. Thicker asphalt sections may
be needed based on the City of Renton requirements, or actual traffic data, truck loads, and intended use.
All paved and landscaped areas should be graded so that surface drainage is directed to appropriate catch
basins.
5.9.3. Portland Cement Concrete Pavement
PCC sections may be considered for areas where concentrated heavy loads may occur. We recommend
that these pavements consist of at least 6 inches of PCC over 6 inches of CSBC over a 12-inch-thick
March 10, 2022 | Page 18 File No. 24939-001-00
subbase. A thicker concrete section may be needed based on the actual load data for use of the area. If
the concrete pavement will have doweled joints, we recommend that the concrete thickness be increased
by an amount equal to the diameter of the dowels. The base and subbase layers should be compacted to
at least 95 percent of the MDD. The subbase layer may consist of imported gravel borrow.
We recommend PCC pavements incorporate construction joints and/or crack control joints spaced at
maximum distances of 12 feet apart, center-to-center, in both the longitudinal and transverse directions.
Crack control joints may be created by placing an insert or groove into the fresh concrete surface during
finishing, or by saw cutting the concrete after it has initially set-up. We recommend the depth of the crack
control joints be approximately one fourth the thickness of the concrete; or about 1½ inches deep for the
recommended concrete thickness of 6 inches. We also recommend the crack control joints be sealed with
an appropriate sealant to help restrict water infiltration into the joints.
5.9.4. Asphalt-Treated Base
If pavements are constructed during the wet seasons, consideration may be given to covering the areas to
be paved with asphalt-treated base (ATB) for protection. Light-duty pavement areas should be surfaced with
3 inches of ATB, and heavy-duty pavement areas should be surfaced with 6 inches of ATB. ATB placed to
support construction equipment and heavy construction loads should also be at least 6 inches thick, but
should be evaluated by the contractor if thicker sections are needed. Prior to placement of the final
pavement sections, we recommend the ATB surface be evaluated and areas of ATB pavement failure be
removed, and the subgrade repaired. If ATB is used and is serviceable when final pavements are
constructed, the CSBC can be eliminated, and the design PCC or asphalt concrete pavement thickness can
be placed directly over the ATB.
5.10. Construction Dewatering
Static groundwater was observed ranging from about 7½ to 10 feet below existing grades at the site.
Therefore, excavations for utility trenches, underground vaults and elevation shafts may encounter
groundwater.
Dewatering during construction of these areas and other excavations on site may be required. Based on
the soil conditions and our experience in the area, we expect that groundwater in excavations less than
about 7 feet below existing site grades can be controlled by open pumping using sump pumps. For
excavations extending deeper and below the static groundwater table, dewatering using well points or deep
wells will be necessary. We recommend that the contractor be required to submit a proposed dewatering
system design and plan layout to the project team for review and comment prior to beginning construction.
The level of effort for dewatering will depend on the time of year during which construction is accomplished.
Less seepage into the work areas and a lower water table should be expected if construction is
accomplished in the late summer or early fall months, and correspondingly, more seepage and a higher
water table should be expected during the wetter periods of the year and into spring months. We
recommend that earthwork activities be completed in the late summer or early fall months when
precipitation is typically at its lowest.
March 10, 2022 | Page 19 File No. 24939-001-00
5.11. Infiltration Considerations
Groundwater is located about 7½ to 10 feet below existing grades. Fill exists across the site, but generally
at or above the groundwater level. Fill is susceptible to settlement due to stormwater infiltration. The
percent fines in the soil above the groundwater table ranges from 31 to 80 percent. We anticipate that the
design infiltration will be low, about ½-inch per hour or less. If infiltration facilities are planned for the site,
pilot infiltration tests will be required at the proposed locations of the infiltration facilities. In addition, an
evaluation will be needed to assess dewatering induced settlement and mounding effects in the fill.
6.0 RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES
Throughout this report, recommendations are provided where we consider additional geotechnical services
to be appropriate. These additional services are summarized below:
■ GeoEngineers should be retained to review the project plans and specifications when complete to
confirm that our design recommendations have been implemented as intended.
■ During construction, GeoEngineers should observe stripping and grading; observe and evaluate
installation of augercast piles; observe and evaluate the suitability of foundations, wall and floor slab
subgrades; observe removal of unsuitable fill and debris/rubble from below the building footprints and
hardscape areas; observe and test structural fill including wall and utility trench backfill; observe
installation of subsurface drainage measures; evaluate suitability of pavement subgrades and other
appurtenant structures, and provide a summary letter of our construction observation services.
The purpose of GeoEngineers’ construction phase services is to confirm that the subsurface conditions
revealed during the work differ from those anticipated, to evaluate whether or not earthwork and foundation
installation activities are completed in accordance with our recommendations, and other reasons as
described in Appendix D, Report Limitations and Guidelines for Use.
7.0 LIMITATIONS
We have prepared this report for the exclusive use of Bay West Development Holdings, LLC and their
authorized agents for the 800 Garden Mixed-Use Development project Renton, Washington.
Within the limitations of scope, schedule and budget, our services have been executed in accordance with
generally accepted practices in the field of geotechnical engineering in this area at the time this report was
prepared. No warranty or other conditions, express or implied, should be understood.
Any electronic form, facsimile, or hard copy of the original document (email, text, table and/figure), if
provided, and any attachments are only a copy of the original document. The original document is stored
by GeoEngineers, Inc. and will serve as the official document of record. Please refer to Appendix D for
additional information pertaining to use of this report.
March 10, 2022 | Page 20 File No. 24939-001-00
8.0 REFERENCES
D. R. Mullineaux, 1965. “Geologic Map of the Renton Quadrangle, King County, Washington.” National
Geologic Map Database. U.S. Geological Survey (USGS).
Yount, James C., Minard, James P., and Dembroff, Glenn R., 1993. “Geologic Map of Surficial Deposits in
the Seattle 30’ x 60’ Quadrangle, Washington.” National Geologic Map Database. U.S. Geological
Survey (USGS).
ASCE 7-10, 2010. “Minimum Design Loads for Buildings and Other Structures,” American Society of Civil
Engineers.
ASTM D-1557, 2012. “Standard Testing Method for Laboratory Compaction Characteristics of Soil Using
Modified Effort,” ASTM International.
GeoEngineers, Inc., 2006. “Geotechnical Engineering Services Lowe’s of Renton Site, Renton, Washington.”
GeoEngineers’ File No. 8335-003-00.
Kleinfelder, 2001 “Geotechnical Investigation Report Proposed Fry’s Electronics Superstore No. 30, 900
Garden Avenue North, Renton, WA.”
Naval Facilities Engineering Command, 1986. “Foundations & Earth Structures.”
Idriss, I.M. and Boulanger, R.W., 2014. “CPT and SPT Based Liquefaction Triggering Procedures.”
International Code Council, 2018. “International Building Code.”
Idriss, I. M., and R. W. Boulanger, 2008. “Soil Liquefaction during Earthquakes.” Earthquake Engineering
Research Institute MNO-12.
USGS Unified Hazard Tool (Version Dynamic: Conterminous U.S. 2014 (update) (v4.2.0)).
Ishihara, K., and Yoshimine M., “Evaluation of Settlements in Sand Deposits Following Liquefaction During
Earthquakes,” Soils and Foundations, 32(1), 1992, pp. 1773-188.
Tokimatsu K., Seed H.B. 1987. “Evaluation of settlements in sands due to earthquake shaking,” Journal of
Geotechnical Engineering, 1987, vol. 113, pp. 861-878.
Youd, T. L. and Idriss, I. M. 2001. “Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER
and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils,” Journal of
Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 4, April 2001, pp. 298-313
Washington State Department of Transportation, 2020. “Standard Specifications for Road, Bridge and
Municipal Construction.”
FIGURES
n Ave NE
NE
1
2
t
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S
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1
6
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900
Gene Coulon
Memorial Beach
Park
B urlingtonNorthern Santa
FeN 6th St N
6
t
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StGarden
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4
t
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S
t Houser Way BypN 8th St
N 10th
S
t
N
L
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W
a
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N
1
0t
h Pl
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5
th
S
t
Williams Ave NBurnettAveNN
6
t
h
S
t Park Ave NLoganAve NSouthport Dr N
900
900
900
405
The Landing
NE
1
2
t
h
S
t
NE 16th
S
t
N E 16th
SndsAve NEEdmonds Ave NE
NE
1
0
t
h
S
t
NE
9
t
h
St
NE
5
t
h
P
l
NE 6t h P l900
Windsor Hills
Park
SITE
Vicinity Map
Figure 1
800 Garden Development
Renton, Washington
3
Alpine Lakes
Wilderness
Kent
Tacoma
Seattle
1,000 1,0000
Feet
Data Source: ESRI. World Navigation Map.
Notes:
1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist inshowing features discussed in an attached document. GeoEngineers, Inc.cannot guarantee the accuracy and content of electronic files. The masterfile is stored by GeoEngineers, Inc. and will serve as the official record ofthis communication.
Projection: NAD 1983 UTM Zone 10N
P:\24\24939001\GIS\24939001_Project\24939001_Project.aprx\2493900100_F01_VicinityMap Date Exported: 01/27/21 by ccabrera
STOPGGGSTOPSTOP
STOP
STOPSTOPSTOP STOP
NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
GSTOPSTOP
STOPNO PARKING
F
IRE LANENO PARK
ING
FIRE
LANENO PARKING
FIRE
LANESTOPCP #1CP #
2
CP #3CP #4CP #5 CP #6
CP #7CP #8CP #9CP #1030'30'30'30'30'30'C1C2
C3 C4C5
L3C2
30
30
30303131 31
31
32
33
31
31
323333
31
32
34 3335
3334 333432
33
34
34
34 3534
3333 343535
33
34 3434
3435 3434 353433
3334
34 3534353435353634353633333435 3635363637
3637
3838
3534 363738
3738
3534
34
3536
34 34
34
3
434343536
363535
3435
34
36
37
353535
353433
34
34 35
34
34
36
35
34
34
36
35353
637
35
34
34
36
36
3534
353535
343331
32
3
2
32
32
33 3435
32
33
34
34
33353637353531 363
3 34
34
323432
33 34
34
32
8-STORY MIXED USE-PHASE 1 7-STORY MIXED USE-PHASE 2
7-STORY MIXED USE-PHASE 3
N 10th StGarden Ave NPrivate DriveFry's ElectronicsN 8th StA'A B'BC'CB-1
B-2
B-3
B-4
CPT-1
CPT-2
CPT-3
CPT-4
CPT-5
CPT-6
CPT-7
CPT-8
B-3
B-7
B-6
B-14
B-13
B-15
B-11
B-10
B-5
B-7
B-9
B-8
B-6
B-4
B-1
B-2
B-3
B-18
B-19
B-20
B-16
B-17
B-12
Figure 2
800 Garden Development
Renton, Washington
Site Plan
\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F02_Site Plan.dwg TAB:F02 Date Exported: 03/09/22 - 15:14 by mwoodsProposed
Layout
WENSNotes:
1. The locations of all features shown are approximate.
2. This drawing is for information purposes. It is intended to
assist in showing features discussed in an attached
document. GeoEngineers, Inc. cannot guarantee the
accuracy and content of electronic files. The master file
is stored by GeoEngineers, Inc. and will serve as the
official record of this communication.
Data Source: Topographic Survey from kpff dated
12/21/2020.
Projection: NAD83 Washington State Planes, North Zone, US
Foot Feet
0
Legend
100 100
Boring by GeoEngineers, Inc., 2006B-3
Boring by GeoEngineers, Inc., 2021B-1
CPT-1 Cone Penetrometer Test by GeoEngineers, Inc., 2021
Boring by Kleinfelder, 2001B-1
Cross Section LocationA A'
STOPGGGSTOPSTOP
STOP
STOPSTOPSTOP STOP
NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
GSTOPSTOP
STOPNO PARKING
F
IRE LANENO PARK
ING
FIRE
LANENO PARKING
FIRE
LANESTOPCP #1CP #2CP #3CP #
4
CP #
5
CP #6CP #7
CP #
8CP #9
CP #10
30'30'30'30'30'30'C1C2
C3
C4
C5
L3C2
30
30
30303131 31
31
32
33
31
31
323333
31
32
34 3335
3334 333432
33
34
3
4
34 3534
3333 343535
33
34 3434
3435 3434 353433
3334
34 3534353435353634353633333435 3635363637
3637
3838
3534 363738
3738
3534
34
3536
34 34
34
3434343536
363535
3435
34
36
37
353535
353433
34
34 35
34
34
36
35
34
34
36
35353
637
35
34
34
36
36
3534
353535
343331
32
3
2
32
32
33 3435
32
33
34
34
33353637353531 363
3 34
3
4
323432
33 3434
32
N 8th StGarden Ave NPrivate DriveFry's ElectronicsN 10th St-20
-10
-26
-24
-22
-18
-16
-14
-12
-10
-18
-16
-14
-12
-8
-30
-20
-10
-34
-32
-28
-26
-24 -22
-18
-16
-14
-12
-8
-6
-4
-30
-32
8-STORY MIXED USE-PHASE 1 7-STORY MIXED USE-PHASE 2
7-STORY MIXED USE-PHASE 3 A'A B'BC'CB-1
-21.00
B-2
-11.00
B-3
-31.00
B-4
-25.00
CPT-1
-31.00
CPT-2
-3.00
CPT-3
-10.00 CPT-4
-7.00
CPT-5
CPT-6
CPT-7
-5.00
CPT-8
-36.00
B-15
B-11
B-10
B-5
-16.00
B-7
-30.00
B-9
-6.00
B-8
-18.00
B-6
-21.00
B-4
-27.00
B-1
-28.00
B-2
B-3
B-18
B-19
B-20
B-16
B-17
-30
-20
-28
-26
-24
-22
Figure 3
800 Garden Development
Renton, Washington
Bearing Soils Contour Map
\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F03_Bearing Contours Elevation Map.dwg TAB:F03 Date Exported: 03/09/22 - 15:14 by mwoodsWENSFeet
0100 100
Legend
Boring by GeoEngineers, Inc., 2006B-3
Boring by GeoEngineers, Inc., 2021B-1
CPT-1 Cone Penetrometer Test by GeoEngineers, Inc., 2021
Boring by Kleinfelder, 2001B-1
Cross Section LocationA A'
Notes:
1. The locations of all features shown are approximate.
2. This drawing is for information purposes. It is intended to
assist in showing features discussed in an attached
document. GeoEngineers, Inc. cannot guarantee the
accuracy and content of electronic files. The master file
is stored by GeoEngineers, Inc. and will serve as the
official record of this communication.
Data Source: Topographic Survey from kpff dated
12/21/2020.
Projection: NAD83 Washington State Planes, North Zone, US
Foot Bearing Soils Contour-26
Elevation (Feet)Elevation (Feet)Distance (Feet)
-60
-40
-20
0
20
40
60
-60
-40
-20
0
20
40
60
0 100 200 300 400 500 600 700 800 900 1000 1050
Existing BuildingExisting Grade
A
(North)
A'
(South)
7-Story Mixed Use
Phase 1
7-Story Mixed Use
Phase 2
7-Story Mixed Use
Phase 3
B-1(11 ft)B-4(65 ft)CPT-7(20 ft)B-5(30 ft)B-2 (Kleinfelder)(9 ft)B-19(9 ft)B-16(9 ft)B-2(72 ft)B-8 (Kleinfelder)(1 ft)30'B-10 (Kleinfelder)(38 ft)40'
QT (tsf)
0 500
26
15
5
ML/SM
SM
PT
50/5"*
28
18
5
3
3
4
4
6
38
7
12
28
40
50
56
60
GP-GM
SM
ML
PT
SM
OH
PT
SM
CL
ML
SM
SP-SM
35
18
3
GP
ML/SM
SP
PT
OL
17
22
17
4
6
4
5
19
26
5
45
34
34
43
42
36
38
GPSMML
ML
PT
SM
PT
SP-SM
SM
CL
SP-SM
19
7
12
SMGP
SM/ML
SANDPTOL
SP
31
18
5
6
GP
SM/ML
PT
4
45
16
26
42
52
29
SM
SP
17
12
4
GP
SM/ML
PT
SP
SP
SP
20
12
39
35
10
15
17
48
OL
SP
SP
34
18
6
20
GP
SM
SM/ML
PT
SP
GP
34
20
11
4
SP
SP
PL
PT
9
8
17
44
SP
OL/PT
CL
SP
36
41
23
23
7
5
3
26
24
38
12
12
19
13
17
45
44
78
40
GP-GM
ML
ML
PT
SM
SP-SM
PT
ML
CL
SM
SP-SM
ML
15
3
12
GP
SM
SM/ML
PT
SP
24
28
Fill
Upper Alluvium
Lower Alluvium
Figure 4
Cross Section A-A'\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F04-6_Cross Sections.dwg TAB:F04 Date Exported: 03/02/22 - 16:05 by mwoods800 Garden Development
Renton, Washington
Legend
Notes:
1. The subsurface conditions shown are based on
interpolation between widely spaced explorations
and should be considered approximate; actual
subsurface conditions may vary from those shown.
2. This figure is for informational purposes only. It is
intended to assist in the identification of features
discussed in a related document. Data were
compiled from sources as listed in this figure. The
data sources do not guarantee these data are
accurate or complete. There may have been
updates to the data since the publication of this
figure. This figure is a copy of a master document.
The hard copy is stored by GeoEngineers, Inc. and
will serve as the official document of record.
Datum: NAVD 88, unless otherwise noted.
Groundwater observed
Legend
SM
20
Boring
Soil Classification
Blow CountBoring ID(Offset)Inferred Soil Contact
QT (tsf)
0 500
Cone Penetration Test
Tip Resistance
Horizontal Scale in Feet
0100 100
Vertical Scale in Feet
020 20
Vertical Exaggeration: 5X
Fill
Upper Alluvium
Lower AlluviumCPT ID(Offset)
Elevation (Feet)Elevation (Feet)Distance (Feet)
-70
-60
-40
-20
0
20
40
-70
-60
-40
-20
0
20
40
0 50 100 150 200 250 300 350 400 440
Existing Grade
B
(West)
B'
(East)B-2(60 ft)CPT-3(33 ft)B-18(45 ft)B-19 (Kleinfelder)(38 ft)B-20 (Kleinfelder)(38 ft)QT (tsf)
0 500
QT (tsf)
0 500
19
6
3
ML/SM
GP
PTML
35
18
3
GP
ML/SM
SP
PT
OL
PT
ML/SM
GP
28
24
2
17
22
17
4
6
4
5
19
26
5
45
34
34
43
42
36
38
GPSMML
ML
PT
SM
PT
SP-SM
SM
CL
SP-SM
Fill
Upper Alluvium
Lower AlluviumCPT-8 (Kleinfelder)(13 ft)50 50
Figure 5
Cross Section B-B'\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F04-6_Cross Sections.dwg TAB:F05 Date Exported: 03/02/22 - 16:09 by mwoods800 Garden Development
Renton, Washington
Horizontal Scale in Feet
050 50
Vertical Scale in Feet
020 20
Vertical Exaggeration: 2.5X
Legend
Notes:
1. The subsurface conditions shown are based on
interpolation between widely spaced explorations
and should be considered approximate; actual
subsurface conditions may vary from those shown.
2. This figure is for informational purposes only. It is
intended to assist in the identification of features
discussed in a related document. Data were
compiled from sources as listed in this figure. The
data sources do not guarantee these data are
accurate or complete. There may have been
updates to the data since the publication of this
figure. This figure is a copy of a master document.
The hard copy is stored by GeoEngineers, Inc. and
will serve as the official document of record.
Datum: NAVD 88, unless otherwise noted.
Groundwater observed
Legend
SM
20
Boring
Soil Classification
Blow CountBoring ID(Offset)Inferred Soil Contact
QT (tsf)
0 500
Cone Penetration Test
Tip Resistance
Fill
Upper Alluvium
Lower AlluviumCPT ID(Offset)
Elevation (Feet)Elevation (Feet)Distance (Feet)
-60
-40
-20
0
20
40
60
-60
-40
-20
0
20
40
60
0 50 100 150 200 250 300 350 400 450 500
Existing Grade
Existing Building
C
(West)
C'
(East)CPT-4(48 ft)B-5(17 ft)B-6(2 ft)B-4(22 ft)QT (tsf)
0 500
25
2
4
GP
SM
SM/ML
SP
OL
14
56
5
13
SP
OL/PT
ML
SP
PT12
7
9
27
OL
PT
SP
27
35
44
35
SP
17
12
4
GP
SM/ML
PT
SP
SP
SP
20
12
39
35
10
15
17
48
OL
SP
SP
34
35
8
13
GP
SP
PT
GP
SP14
12
19
6
SPOL
PT
SP
OL
OH
24
43
16
38
51
SP
GP
SM
Fill
Upper Alluvium
Lower Alluvium
5
27
7
6
2
5
30
7
7
12
9
11
10
19
39
41
65
SM
SM
OL
SM
ML
PT
SP-SM
PT
SM
ML
PT
CL
ML
SM
SP-SMB-3(110 ft)10'
Figure 6
Cross Section C-C'\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F04-6_Cross Sections.dwg TAB:F06 Date Exported: 03/02/22 - 16:09 by mwoods800 Garden Development
Renton, Washington
Horizontal Scale in Feet
050 50
Legend
Notes:
1. The subsurface conditions shown are based on
interpolation between widely spaced explorations
and should be considered approximate; actual
subsurface conditions may vary from those shown.
2. This figure is for informational purposes only. It is
intended to assist in the identification of features
discussed in a related document. Data were
compiled from sources as listed in this figure. The
data sources do not guarantee these data are
accurate or complete. There may have been
updates to the data since the publication of this
figure. This figure is a copy of a master document.
The hard copy is stored by GeoEngineers, Inc. and
will serve as the official document of record.
Datum: NAVD 88, unless otherwise noted.
Groundwater observed
Legend
SM
20
Boring
Soil Classification
Blow CountBoring ID(Offset)Inferred Soil Contact
QT (tsf)
0 500
Cone Penetration Test
Tip Resistance
Fill
Upper Alluvium
Lower Alluvium
Vertical Scale in Feet
020 20
Vertical Exaggeration: 2.5XCPT ID(Offset)
Materials:
SLOPED TO DRAIN
AWAY FROM STRUCTURE
EXTERIOR WALL
WALL DRAINAGE MATERIAL
FLOOR SLAB
6 INCHES
CAPILLARY BREAK
2' MIN.RETAINED SOIL
4" DIAMETER
PERFORATED
DRAIN PIPE
DAMP PROOFING
VAPOR RETARDER,
PER PLANS
TEMPORARY
EXCAVATION SLOPE
NOT TO SCALE
12" MIN. COVER OF
DRAINAGE MATERIAL
(6" MIN. ON SIDES OF PIPE)
Figure 7
Wall Drainage and Backfill
\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F07_Wall Drainage and Backfill.dwg TAB:F07 Date Exported: 03/02/22 - 16:13 by mwoodsPAVEMENT OR 24" LOW
PERMEABILITY SOIL
A. WALL DRAINAGE MATERIAL: Shall consist of washed gravel such as Seattle Mineral Aggregate Type 5 or "Gravel
Backfill for Drains" per WSDOT Standard Specification 9-03.12(4), surrounded with a non-woven geotextile such as
Mirafi 140N (or approved equivalent). Alternatively Seattle Mineral Aggregate Type 26 may be used without a
geotextile fabric between the drainage material and retained soil. However a minimum of 12 inches of Type 5 or
"Gravel Back Fill for Drains" surrounded with a geotextile fabric should be used around the drain pipe.
B. RETAINED SOIL: Should consist of structural fill, either on-site soil or imported. The backfill should be compacted
in loose lifts not exceeding 6 inches. Wall backfill supporting building floor slabs should consist of imported sand and
gravel such as Seattle Mineral Aggregate Type 17 or WSDOT Standard Specification 9-03.14 compacted to at least 95
percent ASTM D1557. Backfill not supporting building floor slabs, sidewalks, or pavement should be compacted to 90
to 92 percent of the maximum dry density, per ASTM D1557. Backfill supporting sidewalks or pavement areas should
be compacted to at least 95 percent in the upper two feet. Only hand-operated equipment should be used for
compaction within 5 feet of the walls and no heavy equipment should be allowed within 5 feet of the wall.
C. CAPILLARY BREAK: Should consist of at least 6 inches of clean crushed gravel with a maximum size of 1-inch
and negligible sand or fines, such as Seattle Mineral Aggregate Type 28 or WSDOT Standard Specifications Section
9-03.1(4), grading No. 67.
D. PERFORATED DRAIN PIPE: Should consist of a 4-inch diameter perforated heavy-wall solid pipe (SDR-35 PVC) or
rigid corrugated polyethylene pipe (ADS N-12) or equivalent. Drain pipes should be placed with 0.25 percent minimum
slopes and discharge to the storm water collection system.
800 Garden Development
Renton, Washington
Figure 8
\\geoengineers.com\WAN\Projects\24\24939001\CAD\00\Geotech\2493900100_F08_Compaction Crtieria.dwg TAB:F08 Date Exported: 03/02/22 - 16:14 by mwoods800 Garden Development
Renton, Washington
Compaction Criteria for Trench Backfill
95
90 90
9590
Pipe
Varies
Varies
(See Note 1)
2 Feet
Varies
(Modified Proctor)
Pipe Bedding
Trench Backfill
Base Course
Concrete or Asphalt Pavement
Maximum Dry Density, by Test Method ASTM D1557
Recommended Compaction as a Percentage of
Legend
95
Not To Scale
Notes:
1. All backfill under building areas should be compacted to at
least 95 percent per ASTM D1557.
Non-structural
Areas
Hardscape Or
Pavement
Areas
Ground Surface
0.01
0.1
1
10
0.01 0.1 15% Damped Spectral Acceleration, Sa(g)Period (seconds)
ASCE 7-10 Site Class E MCEr
0.8 x ASCE 7-10 Site Class E MCEr
Deterministic (MCE) Response Spectrum
Site-Specific Probabilistic MCEr Response
Spectrum
Recommended Site-Specific MCEr Response
Spectrum
Recommended Site-Specific MCER Response Spectrum
800 Garden Development
Renton, Washington
Figure 9
Project: 24939-001-00 Executed: 03/03/2022
APPENDICES
APPENDIX A Field Explorations
March 10, 2022 | Page A-1 File No. 24939-001-00
APPENDIX A
FIELD EXPLORATIONS
Subsurface conditions were explored by advancing four mud-rotary borings (B-1 through B-4) and
performing eight cone penetration tests (CPT-1 through CPT-8).
Borings
Subsurface soil and groundwater conditions were evaluated by completing four borings (B-1 through B-4)
on February 1 and February 2, 2021. The borings were completed to depths of about 75 feet below the
existing ground surface. The boring locations were determined by measuring from existing site features and
using a hand-held GPS unit. The approximate boring locations are shown on Figure 2.
The borings were completed by Holocene Drilling, Inc. using a truck-mounted drill rig using mud rotary
drilling methods. The borings were continuously monitored by a representative from our firm who reviewed
and classified the soils encountered, obtained representative samples, observed groundwater conditions
and prepared a detailed log of each exploration.
The soils encountered in the borings were generally sampled at 2½- and 5-foot vertical intervals with a
2-inch outside-diameter split-barrel standard penetration test (SPT) sampler. The disturbed samples were
obtained by driving the sampler 18 inches into the soil with a 140-pound automatic hammer free-falling
30 inches. The number of blows required for each 6 inches of penetration was recorded. The blow count
(“N-value”) of the soil was calculated as the number of blows required for the final 12 inches of penetration.
This resistance, or N-value, provides a measure of the relative density of granular soils and the relative
consistency of cohesive soils. Where very dense soil conditions precluded driving the full 18 inches, the
penetration resistance for the partial penetration was entered on the logs. The blow counts are shown on
the boring logs at the respective sample depths.
Soils encountered in the borings were visually classified in general accordance with the classification
system described in Figure A-1. A key to the boring log symbols is also presented in Figure A-1. The logs of
the borings are presented in Figures A-2 through A-5. The boring logs are based on our interpretation of the
field and laboratory data and indicate the various types of soils and groundwater conditions encountered.
The logs also indicate the depths at which these soils or their characteristics change, although the change
may actually be gradual. If the change occurred between samples, it was interpreted. The relative densities
noted on the boring logs are based on the blow count data obtained in the borings and judgment based on
the conditions encountered.
Observations of groundwater conditions were made during drilling. The groundwater conditions
encountered during drilling are presented on the boring logs. Groundwater conditions observed during
drilling represent a short-term condition and may or may not be representative of the long-term groundwater
conditions at the site. Groundwater conditions observed during drilling should be considered approximate.
Cone Penetration Tests
The eight CPTs (CPT-1 through CPT-8) were completed between February 3 and 5, 2021 by In-Situ
Engineering under subcontract to GeoEngineers, Inc. The CPT is a subsurface exploration technique in
which a small-diameter steel conical tip with adjacent sleeve is continuously advanced with hydraulically
March 10, 2022 | Page A-2 File No. 24939-001-00
operated equipment. Measurements of the tip and sleeve resistance allow interpretation of the soil profile
and the consistency of the strata penetrated. The tip resistance, friction ratio and pore water pressure are
recorded on the CPT logs. The approximate CPT locations are shown on Figure 2. The logs of the CPT
soundings are presented on Figures A-6 through A-13. The CPT soundings were backfilled in accordance
with procedures outlined by the Washington State Department of Ecology.
SYMBOLS TYPICAL
DESCRIPTIONS
GW
GP
SW
SP
SM
FINEGRAINED
SOILS
SILTS ANDCLAYS
NOTE: Multiple symbols are used to indicate borderline or dual soil classifications
MORE THAN 50%RETAINED ONNO. 200 SIEVE
MORE THAN 50%PASSINGNO. 200 SIEVE
GRAVEL
ANDGRAVELLYSOILS
SC
LIQUID LIMITLESS THAN 50
(APPRECIABLE AMOUNTOF FINES)
(APPRECIABLE AMOUNTOF FINES)
COARSEGRAINEDSOILS
MAJOR DIVISIONS GRAPH LETTER
GM
GC
ML
CL
OL
SILTS AND
CLAYS
SANDS WITHFINES
SANDANDSANDY
SOILS
MH
CH
OH
PT
(LITTLE OR NO FINES)
CLEAN SANDS
GRAVELS WITHFINES
CLEAN GRAVELS
(LITTLE OR NO FINES)
WELL-GRADED GRAVELS, GRAVEL -SAND MIXTURES
CLAYEY GRAVELS, GRAVEL - SAND -CLAY MIXTURES
WELL-GRADED SANDS, GRAVELLYSANDS
POORLY-GRADED SANDS, GRAVELLYSAND
SILTY SANDS, SAND - SILT MIXTURES
CLAYEY SANDS, SAND - CLAYMIXTURES
INORGANIC SILTS, ROCK FLOUR,CLAYEY SILTS WITH SLIGHTPLASTICITY
INORGANIC CLAYS OF LOW TOMEDIUM PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS,LEAN CLAYS
ORGANIC SILTS AND ORGANIC SILTYCLAYS OF LOW PLASTICITY
INORGANIC SILTS, MICACEOUS ORDIATOMACEOUS SILTY SOILS
INORGANIC CLAYS OF HIGHPLASTICITY
ORGANIC CLAYS AND SILTS OFMEDIUM TO HIGH PLASTICITY
PEAT, HUMUS, SWAMP SOILS WITHHIGH ORGANIC CONTENTSHIGHLY ORGANIC SOILS
SOIL CLASSIFICATION CHART
MORE THAN 50%OF COARSEFRACTION RETAINEDON NO. 4 SIEVE
MORE THAN 50%OF COARSEFRACTION PASSINGON NO. 4 SIEVE
SILTY GRAVELS, GRAVEL - SAND -SILT MIXTURES
POORLY-GRADED GRAVELS,GRAVEL - SAND MIXTURES
LIQUID LIMIT GREATERTHAN 50
Continuous Coring
Bulk or grab
Direct-Push
Piston
Shelby tube
Standard Penetration Test (SPT)
2.4-inch I.D. split barrel
NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions.Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to berepresentative of subsurface conditions at other locations or times.
Blowcount is recorded for driven samplers as the number ofblows required to advance sampler 12 inches (or distance noted).See exploration log for hammer weight and drop.
"P" indicates sampler pushed using the weight of the drill rig.
"WOH" indicates sampler pushed using the weight of thehammer.
Key to Exploration Logs
Figure A-1
Sampler Symbol Descriptions
ADDITIONAL MATERIAL SYMBOLS
NSSSMSHS
SYMBOLS
Asphalt Concrete
Cement Concrete
Crushed Rock/Quarry Spalls
Topsoil
GRAPH LETTER
AC
CC
SOD Sod/Forest Duff
CR
DESCRIPTIONS
TYPICAL
TS
%F%GALCACPCSDDDSHAMCMDMohsOCPMPIPLPPSATXUCVS
Groundwater Contact
Measured groundwater level in exploration, well, or piezometer
Measured free product in well or piezometer
Graphic Log Contact
Distinct contact between soil strata
Approximate contact between soil strata
Material Description Contact
Contact between geologic units
Contact between soil of the same geologic unit
Laboratory / Field Tests
Percent finesPercent gravelAtterberg limitsChemical analysisLaboratory compaction testConsolidation testDry densityDirect shearHydrometer analysisMoisture contentMoisture content and dry densityMohs hardness scaleOrganic contentPermeability or hydraulic conductivity Plasticity indexPoint load testPocket penetrometerSieve analysisTriaxial compressionUnconfined compressionVane shear
Sheen Classification
No Visible SheenSlight SheenModerate SheenHeavy Sheen
Rev 09/2020
*Blow counts may not be representative due tocobbles
Groundwater observed at approximately10 feet during drilling
AL (LL = 65, PI = 19)
13
22
138
41
62
311
31
80
40
Approximately 3 inches hot mix asphalt pavement
Gray-brown fine to medium gravel with silt, sand andoccasional cobbles (medium dense, moist) (fill)
Gray silty fine to medium sand (medium dense, moist)
Brown silt with sand, oxidation staining (very stiff,moist)
Dark brown peat (medium stiff, wet) (upper alluvium)
Gray silty fine sand with organic matter (soft, wet)
Dark brown organic silt (soft, wet)
Fibrous peat (soft to medium stiff, wet)
1A1B%F
2
3%F
4AMC4B4C
5%F
6
7AL
8A
8BMC
4
9
13
6
18
18
18
18
50/5" *
28
18
5
3
3
4
4
AC
GP-GM
SM
ML
PT
SM
OH
PT
Notes:
76.5 LSP
KMS Holocene Drilling, Inc.Mud Rotary
Foremost B-58DrillingEquipmentAutohammer140 (lbs) / 30 (in) Drop
WA State Plane NorthNAD83 (feet)1302960184680
34.4NAVD88
Easting (X)Northing (Y)
Start TotalDepth (ft)
Logged By
Checked By
End
Surface Elevation (ft)Vertical Datum
Drilled
HammerData
SystemDatum
Driller DrillingMethod
See "Remarks" section for groundwater observed
2/1/20212/1/2021
Note: See Figure A-1 for explanation of symbols.Coordinates Data Source: Horizontal approximated based on site survey. Vertical approximated based on field survey.
Sheet 1 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-1
Figure A-2
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0
5
10
15
20
25
30
35 Graphic LogGroupClassificationElevation (feet)302520151050
AL (LL = 52, PI = 27)
413
19
51
22
20
26
22
9
Gray silty fine to medium sand (dense, wet)
Gray lean clay with occasional sand interbeds (mediumstiff, wet)
Light brown fat clay (stiff, wet)
Grayish brown silty fine to medium sand (mediumdense, wet) (lower alluvium)
Brown fine to medium sand with silt (dense to verydense, wet)
9MC
10%F
11
12AL
13%F
14%F
15
16
17
18
11
12
17
15
11
15
12
13
6
38
7
12
28
40
50
56
60
SM
CL
ML
SM
SP-SM
Sheet 2 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-1 (continued)
Figure A-2
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)35
40
45
50
55
60
65
70
75 Graphic LogGroupClassificationElevation (feet)-5-10-15-20-25-30-35-40
Groundwater observed at approximately9 feet during drilling
21
210
42
257
304
37
60
38
10
Approximately 11 inches hot mix asphalt pavement
Brown fine to coarse gravel with sand and occasionalcobbles (medium dense, moist) (fill)
Gray silty fine to medium sand with gravel (mediumdense, moist)
Gray sandy silt with gravel (very stiff, moist)
Gray silt with sand and occasional gravel (very stiff,moist)
Dark brown fibrous peat (soft, wet) (upper alluvium)
Gray silty fine to medium sand (loose, wet)
Dark brown fibrous peat (soft, wet)
With solid wood, becomes medium stiff
Gray fine to medium sand with silt and occasionalorganic matter (medium dense, wet)
1A
1B
2%F
3
4MC
5%F
6MC
7MC
8%F
18
13
14
15
11
18
15
11
17
22
17
4
6
4
5
19
AC
GP
SM
ML
ML
PT
SM
PT
SP-SM
Notes:
76.5 LSP
KMS Holocene Drilling, Inc.Mud Rotary
Foremost B-58DrillingEquipmentAutohammer140 (lbs) / 30 (in) Drop
WA State Plane NorthNAD83 (feet)1303100184470
33.83NAVD88
Easting (X)Northing (Y)
Start TotalDepth (ft)
Logged By
Checked By
End
Surface Elevation (ft)Vertical Datum
Drilled
HammerData
SystemDatum
Driller DrillingMethod
See "Remarks" section for groundwater observed
2/1/20212/1/2021
Note: See Figure A-1 for explanation of symbols.Coordinates Data Source: Horizontal approximated based on site survey. Vertical approximated based on field survey.
Sheet 1 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-2
Figure A-3
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0
5
10
15
20
25
30
35 Graphic LogGroupClassificationElevation (feet)302520151050
56
17 6
Without organic matter
Brown silty fine to medium sand (loose, wet)
Gray lean clay (medium stiff, wet)
Gray fine sand with silt (dense, wet) (lower alluvium)
9
10A10BMC
11
12%F
13
14
15
16
17
12
12
14
17
16
15
15
16
13
26
5
45
34
34
43
42
36
38
SM
CL
SP-SM
Sheet 2 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-2 (continued)
Figure A-3
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)35
40
45
50
55
60
65
70
75 Graphic LogGroupClassificationElevation (feet)-5-10-15-20-25-30-35-40
Groundwater observed at approximately7½ feet during drilling
AL (LL = 46, PI = 18)
14
49
30
54
434
15
237
39
18
6
Approximately 4 inches hot mix asphalt pavement
Gray-brown silty medium sand with gravel (fill)
Gray silty sand (medium dense, moist)
With organic matter, becomes wet
Brown organic silt (medium stiff, wet) (upper alluvium)
Brownish gray silty sand with organic matter (loose,wet)
Gray silt (very soft, wet)
Brown fibrous peat with solid wood (medium stiff, wet)
Gray fine to coarse sand with silt (medium dense, wet)
Brown amorphous peat (medium stiff, wet)
1
2%F
3
4AMC4B%F
5AL
6MC
7%F
8MC
2
8
15
17
18
14
16
5
27
7
6
2
5
30
7
AC
SM
SM
OL
SM
ML
PT
SP-SM
PT
Notes:
76.5 LSP
KMS Holocene Drilling, Inc.Mud Rotary
Foremost B-58DrillingEquipmentAutohammer140 (lbs) / 30 (in) Drop
WA State Plane NorthNAD83 (feet)1302990183990
34.08NAVD88
Easting (X)Northing (Y)
Start TotalDepth (ft)
Logged By
Checked By
End
Surface Elevation (ft)Vertical Datum
Drilled
HammerData
SystemDatum
Driller DrillingMethod
See "Remarks" section for groundwater observed
2/2/20212/2/2021
Note: See Figure A-1 for explanation of symbols.Coordinates Data Source: Horizontal approximated based on site survey. Vertical approximated based on field survey.
Sheet 1 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-3
Figure A-4
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0
5
10
15
20
25
30
35 Graphic LogGroupClassificationElevation (feet)302520151050
225
39
171
31
21
45
7
Gray silty fine sand (medium dense, wet)
Gray silt (stiff, wet)
Brown to dark brown fibrous peat (stiff, wet)
Gray lean clay (stiff, wet)
Brown silt with sand (very stiff, wet)
Grayish brown silty fine sand (medium dense, wet)
Gray fine to medium sand with silt (dense, wet) (loweralluvium)
Becomes brownish gray, very dense
9MC
10%F
11
12MC
13MC
14A
14B
15%F
16
17
18
15
18
18
15
16
17
14
11
7
12
9
11
10
19
39
41
65
SM
ML
PT
CL
ML
SM
SP-SM
Sheet 2 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-3 (continued)
Figure A-4
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)35
40
45
50
55
60
65
70
75 Graphic LogGroupClassificationElevation (feet)-5-10-15-20-25-30-35-40
Groundwater observed at approximately8 feet during drilling172
40
17
25
10
Approximately 4 inches hot mix asphalt
Gray fine to coarse gravel with occasional silt and sand(medium dense, moist) (fill)
Brown-gray sandy silt with occasional gravel (very stiff,moist)
Oxidation staining
Gray-brown organic silt with sand and gravel (mediumstiff)
Dark brown fibrous peat (stiff, wet) (upper alluvium)
Dark gray silty fine to medium sand with organic matter(very loose, wet)
Gray fine to coarse sand with silt, gravel and occasionalcobbles (medium dense, wet)
Dark brown fibrous peat (stiff, wet)
1A1B
2
3A3BMC
4
5%F
6
7
8A%F8B
16
15
16
1
10
12
9
9
23
23
7
5
3
26
24
38
AC
GP-GM
ML
ML
PT
SM
SP-SM
PT
Notes:
76.5 LSP
KMS Holocene Drilling, Inc.Mud Rotary
Diedrich D-90DrillingEquipmentAutohammer140 (lbs) / 30 (in) Drop
WA State Plane NorthNAD83 (feet)1303260183940
34.89NAVD88
Easting (X)Northing (Y)
Start TotalDepth (ft)
Logged By
Checked By
End
Surface Elevation (ft)Vertical Datum
Drilled
HammerData
SystemDatum
Driller DrillingMethod
See "Remarks" section for groundwater observed
2/2/20212/2/2021
Note: See Figure A-1 for explanation of symbols.Coordinates Data Source: Horizontal approximated based on site survey. Vertical approximated based on field survey.
Sheet 1 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-4
Figure A-5
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0
5
10
15
20
25
30
35 Graphic LogGroupClassificationElevation (feet)302520151050
AL (LL = 26, PI = 11)
88
37
27
17
64
6
Gray sandy silt with interbedded peat layers (stiff, wet)
Gray lean clay (very stiff, wet)
Becomes brown, stiff
Gray silty fine to medium sand (medium dense, wet)
Gray fine to coarse sand with silt (dense to very dense,wet) (lower alluvium)
Gray sandy silt with gravel (hard, wet)
9MC
10%F
11AL
12
13
14%F
15
16A
16B16C
17
13
16
9
18
5
16
15
17
18
12
12
19
13
17
45
44
78
40
ML
CL
SM
SP-SM
ML
Sheet 2 of 2Project Number:
Project Location:
Project:
24939-001-00
Log of Boring B-4 (continued)
Figure A-5
800 Garden Development
Renton, Washington
Date:3/4/21 Path:W:\PROJECTS\24\24939001\GINT\2493900100.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWREMARKS
MoistureContent (%)FinesContent (%)FIELD DATA
MATERIALDESCRIPTION
Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)35
40
45
50
55
60
65
70
75 Graphic LogGroupClassificationElevation (feet)-5-10-15-20-25-30-35-40
CPT_01
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/5/2021 8:25:49 AMPREDRILL: 4.5 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 75.295 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-6
CPT-02
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/3/2021 11:15:00 AMPREDRILL: 4.5 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 65.617 ft
Depth
(ft)
Tip COR
(tsf)
0 7000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-7
CPT-03A
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/3/2021 9:27:58 AMPREDRILL: 3.0 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 75.295 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-8
CPT-04
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/3/2021 2:13:48 PMPREDRILL: 4.5 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 75.459 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-9
CPT-05
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/3/2021 3:42:32 PMPREDRILL: 4.5 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 48.720 ft
Depth
(ft)
Tip COR
(tsf)
0 8000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
09
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-10
CPT_06
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/5/2021 1:05:08 PMPREDRILL: 2.0 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 41.339 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-11
CPT-07
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/3/2021 12:29:51 PMPREDRILL: 4.5 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 65.289 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
Sleeve Stress
(tsf)
08
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 160
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Figure A-12
sCPT_08
CPT CONTRACTOR: In Situ Engineering
CUSTOMER: GeoEngineers INCLOCATION: RentonJOB NUMBER: 24939-001-00COMMENT: 800 Garden DevelopmentCOMMENT:
OPERATOR: Okbay
CONE ID: DDG1369TEST DATE: 2/5/2021 10:09:11 AMPREDRILL: 2 ft BACKFILL: 20% Grout & Bentonite ChipsSURFACE PATCH: Cold Patch
TOTAL DEPTH: 91.699 ft
Depth
(ft)
Tip COR
(tsf)
0 6000
10
20
30
40
50
60
70
80
90
100
F.Ratio
(%)
0 10
Pore Pressure
(psi)
-20 140
SBT FR
(RC 1983)
1 sensitive fine grained
2 organic material
3 clay
4 silty clay to clay
5 clayey silt to silty clay
6 sandy silt to clayey silt
7 silty sand to sandy silt
8 sand to silty sand
9 sand
10 gravelly sand to sand
11 very stiff fine grained (*)
12 sand to clayey sand (*)
*SBT/SPT CORRELATION: UBC-1983
0 12
SPT
(blows/ft)
0 100
Seismic Velocity
(ft/s)
0 1400
Figure A-13
APPENDIX B Laboratory Testing
March 10, 2022 | Page B-1 File No. 24939-001-00
APPENDIX B
LABORATORY TESTING
Soil samples obtained from the borings were transported to our laboratory and examined to confirm or
modify field classifications, as well as to evaluate index properties of the soil samples. Representative
samples were selected for laboratory testing consisting of moisture content, fines content, Atterberg limits
and sieve analyses. The tests were performed in general accordance with test methods of ASTM
International (ASTM) or other applicable procedures.
Moisture Content
Moisture content tests of selected samples were completed in general accordance with ASTM D 2216. The
results of these tests are presented on the exploration logs in Appendix A at the depths at which the
samples were obtained.
Percent Fines Determination
Selected samples were “washed” through the U.S. No. 200-mesh sieve to estimate the relative percentages
of coarse- and fine-grained particles in the soil. The tests were conducted in general accordance with
ASTM D 1140. The percent passing value represents the percentage by weight of the sample finer than the
U.S. No. 200 sieve. These tests were conducted to verify field descriptions and to estimate the fines content
for analysis purposes. The test results are shown on the exploration logs at the respective sample depths.
Atterberg Limits
Atterberg limit tests were completed for selected soil samples. The tests were used to classify the soil as
well as to aid in evaluating index properties and consolidation characteristics of the fine-grained soil
deposits. The liquid limit and the plastic limit were obtained in general accordance with ASTM D 4318.
The results of the Atterberg limits are summarized in Figure B-1.
Note: This report may not be reproduced, except in full, without written approval of GeoEngineers, Inc. Test results are applicable only to
the specific sample on which they were performed, and should not be interpreted as representative of any other samples obtained
at other times, depths or locations, or generated by separate operations or processes. The liquid limit and plasticity index were
obtained in general accordance with ASTM D 4318. GeoEngineers 17425 NE Union Hill Road Ste 250, Redmond, WA 98052 Figure B-1
Atterberg Limits Test Results
800 Garden Development
Renton, Washington
24939-001-00 Date Exported: 02.23.2021Symbol
Boring
Number
Depth
(feet)
Moisture
Content
(%)
Liquid
Limit
(%)
Plasticity
Index
(%)Soil Description
BH-1
BH-1
BH-3
BH-4
25
50
15
45
62
51
54
27
65
52
46
26
19
27
18
11
Elastic silt (MH)
Fat clay (CH)
Silt (ML)
Lean clay (CL)
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100PLASTICITY INDEX LIQUID LIMIT
PLASTICITY CHART
CL-ML ML or OL
CL or OL
OH or MH
CH or OH
APPENDIX C Boring Logs from Previous Studies
March 10, 2022 | Page C-1 File No. 24939-001-00
APPENDIX C
EXPLORATIONS FROM PREVIOUS STUDIES
Appendix C includes boring logs from the following previous studies completed at and in the vicinity of the
project site:
■ The logs of 20 borings (B-1 through B-20) completed in 2001 by Kleinfelder, Inc.
■ The logs of three borings (B-2, B-6, and B-7) completed in 2006 by GeoEngineers, Inc.
The approximate locations of these explorations are shown in Figure 2.
2½ inches asphalt concrete
Brown silty fine to coarse sand with gravel (wet) (fill)
Gray silty fine to medium sand with gravel (dense,
moist)
Grades to loose, wet
Dark brown peat with lenses of gray silty fine to
medium sand (medium stiff, wet) (upper alluvialdeposits)
Gray silty fine sand with thin lenses of peat (very looseto loose, wet)
Brown organic silt with thin lenses of gray fine tomedium sand with silt (medium stiff, wet)
Gray silty fine to medium sand with thin lenses oforganic silt (medium dense, wet)
Organic silt (medium stiff, wet)
Dark brown peat (medium stiff, wet)
pH = 7.0
pH = 7.4
OC = 20%
AL; OC = 9%
%F = 16
pH = 4.6
12
18
18
18
18
18
18
18
AC
SM
SM
PT
SM
OH
SM
OL
PT
31
4
6
4
4
5
11
6
9
1
2
3
4
5
6
7
8
9
10
9
8
125
92
40
157 Dry UnitWeight, lbs/ft3MATERIAL DESCRIPTION
MoistureContent %OTHER TESTS
AND NOTES
SAMPLES
Depth feetIntervalBlows/footWater LevelSub-SampleSample NumberGroupSymbolGraphicLogRecovered (in)Elevation feetGeologic Drill
LCF
Drilling
Method
140 lb hammer/30 in drop
rope and cathead
Drilling
Equipment
Deeprock XL Trailer-mounted
Drill Rig
Checked
ByDate(s)
Drilled
30
Drilling
Contractor
Logged
By
Hammer
Data
Datum/
System
Easting(x):
Northing(y):
Hollow-stem Auger
Auger
Data
SPT
Surface
Elevation (ft)
Sampling
Methods
01/03/06 KGO
Vertical
Datum
26Groundwater
Elevation (ft)Total
Depth (ft)80
3.75-inch ID
Note: See Figure A-1 for explanation of symbols.
30
25
20
15
10
5
0
-5
0
5
10
15
20
25
30
35
Sheet 1 of 3
LOG OF BORING B-3
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-4
V6_GTBORING P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
Gray silty fine sand with thin lenses of organic matter
(loose, wet)
Gray fine sand with lenses of organic silt (loose, wet)
(soft, wet)
Gray fine to medium sand (medium dense, moist)
Gray fine to medium sand with silt and thin lenses of
organic silt (medium dense, wet)
Gray fine to medium sand with silt (medium dense tovery dense, wet) (lower alluvial deposits)
%F = 11
12
18
18
18
18
18
18
18
SM
OL/PT
SP
SP-SM
SP-SM
10
6
20
25
20
34
53
49
11
12
13
14
15
16
17
18
19
39 Dry UnitWeight, lbs/ft3MATERIAL DESCRIPTION
MoistureContent %OTHER TESTS
AND NOTES
SAMPLES
Depth feetIntervalBlows/footWater LevelSub-SampleSample NumberGroupSymbolGraphicLogRecovered (in)Elevation feet-5
-10
-15
-20
-25
-30
-35
-40
-45
35
40
45
50
55
60
65
70
75
Sheet 2 of 3
LOG OF BORING B-3 (continued)
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-4
V6_GTBORING P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
18 46 Dry UnitWeight, lbs/ft3MATERIAL DESCRIPTION
MoistureContent %OTHER TESTS
AND NOTES
SAMPLES
Depth feetIntervalBlows/footWater LevelSub-SampleSample NumberGroupSymbolGraphicLogRecovered (in)Elevation feet-50
-55
-60
-65
-70
-75
-80
-85
-90
80
85
90
95
100
105
110
115
120
Sheet 3 of 3
LOG OF BORING B-3 (continued)
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-4
V6_GTBORING P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
2 inches asphalt concrete
Brown silty fine to medium sand with occasional gravel(medium dense to dense, moist) (fill)
SA; pH = 6.6
Gray silty fine sand with trace organic matter (medium
dense, wet) (upper alluvial deposits)
Groundwater measured on 01/03/06
Concretesurface seal
Bentonite
seal
1-inch
Schedule 80
PVC wellcasing
10-20 sand
backfill
1-inch
Schedule 80PVC screen,
0.020-inchslot width
11
10
AC
SM
SM
18
18
18
12
29
42
37
10
11
1
2
3
4
5
6
WELL
CONSTRUCTION
MATERIAL DESCRIPTION
Elevation feetDry UnitWeight, lbs/ft3MoistureContent %Sub-SampleSample NumberDepth feetBlows/footIntervalGraphic LogGroupSymbolRecovered (in)SAMPLES
Geologic Drill
LCF
3.75-inch ID
Drilling
Method
140 lb hammer/30 in drop
rope and cathead
Drilling
Equipment
Deeprock XL Trailer-mounted
Drill Rig
Checked
ByDate(s)
Drilled
Drilling
Contractor
Logged
By
Hammer
Data
Hollow-stem Auger SPT
Auger
Data
Sampling
Methods
01/03/06 KGO
Datum/
System
Easting(x):
Northing(y):
Vertical
Datum
32Total Exploration
Depth (ft)16.5 Ground Surface
Elevation (ft)
Groundwater
Elevation (ft)23.5
Steel surface
monument
Note: See Figure A-1 for explanation of symbols.
0
5
10
15
20
25
30
35
30
25
20
15
10
5
0
Sheet 1 of 1
LOG OF BORING B-4
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-5
V6_GTWELL P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
1½ inches asphalt concrete
Gray silty fine to medium sand with gravel (mediumdense, moist) (fill)
pH = 6.6
Grades to loose
Brown silty fine to medium sand with gravel and organicmatter (loose, wet) (upper alluvial deposits)
Dark brown peat (soft, wet)Gray sandy silt (soft to medium stiff, wet)
Gray fine sand with silt and organic matter (loose, wet)
Groundwater measured on 01/03/06
Concretesurface seal
Bentonite
seal
1-inch
Schedule 80
PVC wellcasing
10-20 sand
backfill
1-inch
Schedule 80PVC screen,
0.020-inchslot width
15
18
95
AC
SM
SM
PT
ML
SP-SM
12
18
12
18
10
14
11
4
4
6
1
2
3
4
5
6
WELL
CONSTRUCTION
MATERIAL DESCRIPTION
Elevation feetDry UnitWeight, lbs/ft3MoistureContent %Sub-SampleSample NumberDepth feetBlows/footIntervalGraphic LogGroupSymbolRecovered (in)SAMPLES
Geologic Drill
LCF
3.75-inch ID
Drilling
Method
140 lb hammer/30 in drop
rope and cathead
Drilling
Equipment
Deeprock XL Trailer-mounted
Drill Rig
Checked
ByDate(s)
Drilled
Drilling
Contractor
Logged
By
Hammer
Data
Hollow-stem Auger SPT
Auger
Data
Sampling
Methods
01/03/06 KGO
Datum/
System
Easting(x):
Northing(y):
Vertical
Datum
32.5Total Exploration
Depth (ft)16.5 Ground Surface
Elevation (ft)
Groundwater
Elevation (ft)25
Steel surface
monument
Note: See Figure A-1 for explanation of symbols.
0
5
10
15
20
25
30
35
30
25
20
15
10
5
0
Sheet 1 of 1
LOG OF BORING B-5
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-6
V6_GTWELL P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
1¾ inches asphalt concrete
1 inch base courseGray sandy silt with occasional gravel (very stiff to
hard, moist) (fill)
Gray silty fine to medium sand with gravel and
occasional wood debris (dense, wet) (fill)
Dark brown peat (medium stiff to stiff, moist) (upper
alluvial deposits)
Gray silty fine sand (loose, moist)
SA; pH = 7.7
OC = 15%
12
12
12
12
12
AC
GP
SM/ML
SM
PT
SM
37
32
36
35
9
1
2
3
4
5
6
13
15
13
81 Dry UnitWeight, lbs/ft3MATERIAL DESCRIPTION
MoistureContent %OTHER TESTS
AND NOTES
SAMPLES
Depth feetIntervalBlows/footWater LevelSub-SampleSample NumberGroupSymbolGraphicLogRecovered (in)Elevation feetGeologic Drill
LCF
Drilling
Method
140 lb hammer/30 in drop
rope and cathead
Drilling
Equipment
Deeprock XL Trailer-mounted
Drill Rig
Checked
ByDate(s)
Drilled
35
Drilling
Contractor
Logged
By
Hammer
Data
Datum/
System
Easting(x):
Northing(y):
Hollow-stem Auger
Auger
Data
SPT
Surface
Elevation (ft)
Sampling
Methods
01/03/06 KGO
Vertical
Datum
34.25Groundwater
Elevation (ft)Total
Depth (ft)16.5
3.75-inch ID
Note: See Figure A-1 for explanation of symbols.
35
30
25
20
15
10
5
0
0
5
10
15
20
25
30
35
Sheet 1 of 1
LOG OF BORING B-6
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-7
V6_GTBORING P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
1¾ inches asphalt concrete
1 inch base courseBrownish gray silty fine to medium sand with gravel
(medium dense to dense, moist) (fill)
pH = 7.7
pH = 6.0
Dark brown peat (medium stiff, moist) (upper alluvial
deposits)
Gray silty fine sand (loose, moist)
Gray fine sand with silt and thin lenses of organic matter
(loose, wet)
Groundwater measured on 01/03/06
Concrete
surface seal
Bentonite
seal
1-inchSchedule 80
PVC wellcasing
10-20 sand
backfill
1-inchSchedule 80
PVC screen,0.020-inch
slot width
14
19
276
AC
GP
SM
PT
SM
SP-SM
10
2
18
18
18
27
43
13
8
5
1
2
3
4
5
6
WELL
CONSTRUCTION
MATERIAL DESCRIPTION
Elevation feetDry UnitWeight, lbs/ft3MoistureContent %Sub-SampleSample NumberDepth feetBlows/footIntervalGraphic LogGroupSymbolRecovered (in)SAMPLES
Geologic Drill
LCF
3.75-inch ID
Drilling
Method
140 lb hammer/30 in drop
rope and cathead
Drilling
Equipment
Deeprock XL Trailer-mounted
Drill Rig
Checked
ByDate(s)
Drilled
Drilling
Contractor
Logged
By
Hammer
Data
Hollow-stem Auger SPT
Auger
Data
Sampling
Methods
01/03/06 KGO
Datum/
System
Easting(x):
Northing(y):
Vertical
Datum
33Total Exploration
Depth (ft)16.5 Ground Surface
Elevation (ft)
Groundwater
Elevation (ft)25.5
Steel surface
monument
Note: See Figure A-1 for explanation of symbols.
0
5
10
15
20
25
30
35
30
25
20
15
10
5
0
Sheet 1 of 1
LOG OF BORING B-7
Project:
Project Location:
Project Number:
Renton, Washington
Lowe's of Renton
8335-003-00 Figure A-8
V6_GTWELL P:\8\8335003\00\FINALS\833500300.GPJ GEIV6_1.GDT 1/26/06
APPENDIX D Report Limitations and Guidelines for Use
March 10, 2022 | Page D-1 File No. 24939-001-00
APPENDIX D
REPORT LIMITATIONS AND GUIDELINES FOR USE1
This appendix provides information to help you manage your risks with respect to the use of this report.
Geotechnical Services Are Performed for Specific Purposes, Persons and Projects
This report has been prepared for the exclusive use of Bay West Development Holdings, LLC and other
project team members for the proposed 800 Garden Mixed-use Development in Renton, Washington. This
report is not intended for use by others, and the information contained herein is not applicable to other
sites.
GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical
or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction
contractor or even another civil engineer or architect that are involved in the same project. Because each
geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique,
prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our
Client. No other party may rely on the product of our services unless we agree in advance to such reliance
in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third
parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of
scope, schedule and budget, our services have been executed in accordance with our Agreement with the
Client and generally accepted geotechnical practices in this area at the time this report was prepared. This
report should not be applied for any purpose or project except the one originally contemplated.
A Geotechnical Engineering or Geologic Report Is Based on a Unique Set of Project-specific
Factors
This report has been prepared for the proposed 800 Garden Mixed-Use Development located in
Renton, Washington. GeoEngineers considered a number of unique, project-specific factors when
establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates
otherwise, do not rely on this report if it was:
■ Not prepared for you,
■ Not prepared for your project,
■ Not prepared for the specific site explored, or
■ Completed before important project changes were made.
For example, changes that can affect the applicability of this report include those that affect:
■ The function of the proposed structure;
■ Elevation, configuration, location, orientation or weight of the proposed structure;
1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org.
March 10, 2022 | Page D-2 File No. 24939-001-00
■ Composition of the design team; or
■ Project ownership.
If important changes are made after the date of this report, GeoEngineers should be given the opportunity
to review our interpretations and recommendations and provide written modifications or confirmation, as
appropriate.
Subsurface Conditions Can Change
This geotechnical or geologic report is based on conditions that existed at the time the study was performed.
The findings and conclusions of this report may be affected by the passage of time, by manmade events
such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope
instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to determine
if it remains applicable.
Most Geotechnical and Geologic Findings Are Professional Opinions
Our interpretations of subsurface conditions are based on field observations from widely spaced sampling
locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface
tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then
applied our professional judgment to render an opinion about subsurface conditions throughout the site.
Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our
report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions.
Geotechnical Engineering Report Recommendations Are Not Final
Do not over-rely on the preliminary construction recommendations included in this report. These
recommendations are not final, because they were developed principally from GeoEngineers’ professional
judgment and opinion. GeoEngineers’ recommendations can be finalized only by observing actual
subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability
for this report's recommendations if we do not perform construction observation.
Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to
confirm that the conditions encountered are consistent with those indicated by the explorations, to provide
recommendations for design changes should the conditions revealed during the work differ from those
anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our
recommendations. Retaining GeoEngineers for construction observation for this project is the most
effective method of managing the risks associated with unanticipated conditions.
A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation
Misinterpretation of this report by other design team members can result in costly problems. You could
lower that risk by having GeoEngineers confer with appropriate members of the design team after
submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans
and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce
that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing
construction observation.
March 10, 2022 | Page D-3 File No. 24939-001-00
Do Not Redraw the Exploration Logs
Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation
of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical
engineering or geologic report should never be redrawn for inclusion in architectural or other design
drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs
from the report can elevate risk.
Give Contractors a Complete Report and Guidance
Some owners and design professionals believe they can make contractors liable for unanticipated
subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems,
give contractors the complete geotechnical engineering or geologic report, but preface it with a
clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for
purposes of bid development and that the report's accuracy is limited; encourage them to confer with
GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or
prefer. A pre-bid conference can also be valuable. Be sure contractors have sufficient time to perform
additional study. Only then might an owner be in a position to give contractors the best information
available, while requiring them to at least share the financial responsibilities stemming from unanticipated
conditions. Further, a contingency for unanticipated conditions should be included in your project budget
and schedule.
Contractors Are Responsible for Site Safety on Their Own Construction Projects
Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods,
schedule or management of the work site. The contractor is solely responsible for job site safety and for
managing construction operations to minimize risks to on-site personnel and to adjacent properties.
Read These Provisions Closely
Some clients, design professionals and contractors may not recognize that the geoscience practices
(geotechnical engineering or geology) are far less exact than other engineering and natural science
disciplines. This lack of understanding can create unrealistic expectations that could lead to
disappointments, claims and disputes. GeoEngineers includes these explanatory “limitations” provisions in
our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these “Report
Limitations and Guidelines for Use” apply to your project or site.
Geotechnical, Geologic and Environmental Reports Should Not Be Interchanged
The equipment, techniques and personnel used to perform an environmental study differ significantly from
those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical
engineering or geologic report does not usually relate any environmental findings, conclusions or
recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated
contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns
regarding a specific project.
March 10, 2022 | Page D-4 File No. 24939-001-00
Biological Pollutants
GeoEngineers’ Scope of Work specifically excludes the investigation, detection, prevention or assessment
of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations,
recommendations, findings, or conclusions regarding the detecting, assessing, preventing or abating of
Biological Pollutants and no conclusions or inferences should be drawn regarding Biological Pollutants, as
they may relate to this project. The term “Biological Pollutants” includes, but is not limited to, molds, fungi,
spores, bacteria, and viruses, and/or any of their byproducts.
If Client desires these specialized services, they should be obtained from a consultant who offers services
in this specialized field.
800 Garden – Bay West
Appendix D
Appendix D
Project Plans
(Note: The plans included with this report are for reference only and are not scalable. For a complete full-size
set of plans, refer to the permit submittal.)
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
CIVIL COVER SHEET
800 GARDEN
800 GARDEN AVENUE NORTH, RENTON, WA 98057
SECTION 8, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M.
STOPSTOPSTOPSTOP
NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
STOPSTOP·
·
·
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
GENERALIZED UTILITY PLAN
STOPNO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
·
·
·
·
·
·
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
GENERALIZED UTILITY PLAN
STOPSTOPSTOPSTOP
NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
STOPSTOP1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
GRADING, PAVING, & DRAINAGE PLAN
≥
STOPNO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE NO PARKING FIRE LANE
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
GRADING, PAVING, & DRAINAGE PLAN
≥
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
800 GARDEN800 GARDENLAND USE PERMIT APPLICATION
RENTON, WA 98057
800 GARDEN AVE N
Call 811
two business days
before you dig
R
NOT FOR CONSTRUCTION
PRELIMINARY
TYPICAL SECTIONS
800 Garden – Bay West
Appendix E
Appendix E
Correspondence
From: Nathan Janders <NJanders@Rentonwa.gov>
Sent: Monday, March 14, 2022 1:16 PM
To: Cate Kraska
Cc: Thaddeus Egging; Michael Clark
Subject: RE: PRE21-000415 - Flow Control
Hi Cate,
I am not aware of any capacity issues and think that a direct discharge would be viable here.
However, I would also urge you to consider looking at the exceptions under section “A. Peak
Rate Flow Control Standard Areas” as I believe that the project will likely have very close to the
same, if not less, impervious coverage as the current site and therefore would likely result in less
then a 0.15 CFS increase in runoff.
Regards,
NATHAN JANDERS, P.E., Civil Engineer III
City of Renton | CED | Planning Division
1055 S Grady Way | 6th Floor | Renton, WA 98057
Virtual Permit Center | Online Applications and Inspections
(425) 430-7382 | NJanders@rentonwa.gov
From: Cate Kraska <Cate.Kraska@kpff.com>
Sent: Friday, March 11, 2022 8:20 AM
To: Nathan Janders <NJanders@Rentonwa.gov>
Cc: Thaddeus Egging <Thaddeus.Egging@kpff.com>; Michael Clark <Michael.Clark@kpff.com>
Subject: PRE21-000415 - Flow Control
Hi Nathan –
We’d like to confirm our understanding of flow control requirements for the redevelopment at
800 Garden Ave N. It appears the project falls under the direct discharge exemption because it
discharges to Johns Creek downstream of I-405. Do you know of any capacity issues in the
system that would not allow the project to apply the direct discharge exemption? Would you
agree with our understanding of flow control requirements for the project?
Thanks!
Cate Kraska She / Her / Hers
Civil Design Engineer
O 206.622.5822 D 206.926.0505
1601 Fifth Avenue, Suite 1600
Seattle, WA 98101
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