HomeMy WebLinkAboutR_Geotechnical_Report_170428_V1Geotechnical Engineering Report
Taco Bell No. 312178
4225 NE 4th St
Renton, King County, Washington
April 28, 2017
Terracon Project No. 81175027
Prepared for:
Taco Bell of America, LLC
Irvine, California
Prepared by:
Terracon Consultants, Inc.
Mountlake Terrace, Washington
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ............................................................................................................ i
1.0 INTRODUCTION .............................................................................................................1
2.0 PROJECT INFORMATION .............................................................................................1
2.1 Site Location and Description............................................................................1
2.2 Project Description .............................................................................................2
3.0 SUBSURFACE CONDITIONS ........................................................................................2
3.1 Published Geologic Conditions .........................................................................2
3.2 Soil Conditions ...................................................................................................2
3.3 Groundwater .......................................................................................................3
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ......................................3
4.1 Geotechnical Considerations ............................................................................3
4.2 Earthwork ...........................................................................................................4
4.2.1 Site Preparation ......................................................................................5
4.2.2 Material Types.........................................................................................5
4.2.3 Compaction Requirements ....................................................................5
4.2.4 Grading and Drainage .............................................................................6
4.2.5 Construction Considerations ..................................................................6
4.3 Foundations ........................................................................................................7
4.3.1 Design Recommendations .....................................................................7
4.3.2 Construction Considerations ................................................................8
4.4 Floor Slabs..........................................................................................................9
4.4.1 Design Recommendations .....................................................................9
4.4.2 Construction Considerations ..............................................................10
4.5 Seismic Considerations ................................................................................... 10
4.6 Lateral Earth Pressures.................................................................................... 11
4.7 Pavements ........................................................................................................ 13
4.7.1 Subgrade Preparation ...........................................................................13
4.7.2 Design Considerations ..........................................................................14
4.7.4 Pavement Drainage ...............................................................................17
4.7.5 Pavement Maintenance .........................................................................17
5.0 GENERAL COMMENTS ................................................................................................17
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TABLE OF CONTENTS– continued
APPENDIX A – FIELD EXPLORATION
Exhibit A-1 Site Location Map
Exhibit A-2 Site and Exploration Plan
Exhibit A-3 Field Exploration Description
Exhibits A-4 through A-8 Borings B-1 through B-5
APPENDIX B – LABORATORY TESTING
Exhibit B-1 Laboratory Testing
Exhibit B-2 Grain Size Distribution
APPENDIX C – SUPPORTING DOCUMENTS
Exhibit C-1 General Notes
Exhibit C-2 Unified Soil Classification
Geotechnical Engineering Report
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April 28, 2017 ■Terracon Project No. 81175027
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EXECUTIVE SUMMARY
A geotechnical exploration program has been performed for the proposed Taco Bell No. 312178
located in Renton, Washington. Terracon’s geotechnical scope of services included the
advancement of five soil test borings to approximate depths of 11 to 21 ½ feet below existing site
grades. Based upon the geotechnical conditions encountered in the borings and our current
understanding of the proposed development, the site appears suitable for the proposed
improvements. The following geotechnical considerations were identified as having potential
impacts on the design and construction the proposed project:
n We encountered existing fill soils consisting primarily of loose to medium dense sand and
gravel to depths ranging between approximately 3 and 7 feet beneath the existing ground
surface (bgs) at our exploration locations. The two borings that were conducted within the
proposed footprint of the restaurant structure, B-1 and B-2, encountered fill soils to depths
of 5 and 6 feet bgs, respectively. Undocumented fills present an inherent risk of excessive
total and differential settlement of overlying improvements due to uncertainty as it relates
to quality and consistency. Excessive settlement can cause significant damages and
serviceability issues for overlying structures and improvements. We recommend complete
removal of the existing fill soils in the area of the building pad as a means to substantially
reduce potentially damaging settlements. If a lesser level of risk reduction is desired,
appropriate recommendations can be provided upon request.
n An allowable bearing pressure of 3,000 pounds per square foot (psf) can be used for
shallow foundations bearing on suitable native material. Properly placed structural fill can
provide an allowable bearing pressure of 3,000 psf if placed on a properly prepared
subgrade consisting of suitable native soils.
n The existing fill soils encountered at the boring locations have relatively low fines content and
appear suitable for reuse as structural fill if placed at a moisture content near the optimum
value.
n Groundwater was observed while drilling at depths ranging between approximately 10 and
14 feet below the existing ground surface.
SUMMARY OF RECOMMENDATIONS
DESIGN ITEM RECOMMENDED PARAMETER REPORT PAGE NO.
Allowable Bearing Pressure for Footings:
Spread Footing
Wall Footing
3,000 psf
3,000 psf
7
7
Foundation Type Spread footing 7
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Bearing Materials Structural Fill or Native Gravel
and Sand
5
Passive Lateral Resistance (EFP)(ultimate)300 pcf 8
Coefficient of Friction (allowable)0.35 8
Soil Expansion Potential NA NA
Geologic Hazards:
Liquefaction Potential Low 11
Nearest Fault and Magnitude Seattle Fault Zone, M7.0+11
Fault Type Thrust 11
Seismic Site Class D 11
Near-Source Distance 3 miles 11
Seismic Coefficient,FA 1.000 10
Seismic Coefficient,FV 1.500 10
Subsidence Potential NA NA
Pavement
TI equal to 4.5 Light Traffic 3.0” HMA / 6.0” AB 16
TI equal to 7.0 Heavy Traffic 4.0” HMA /3.0” AB 16
Portland Cement Concrete Pavement 6.0” PCC / 4.0” AB 16
Slabs
Building Floor Slabs On Structural Fill 9
Modulus of Subgrade Reaction 150 psi/in 9
Existing Site Conditions
Existing Fill Varies from 3 –7 ft 1 3
Groundwater Depth or Historical High About 10 to 14 ft at time of drilling 3
Near-Surface Corrosivity Not Evaluated -
Estimated Cut and Fill
Final grades very similar to
existing grades. Temporary
construction cuts for utilities,
infiltration gallery, and to remove
existing fill from the building pad1
4
Existing Underground Structures Utilities, existing foundations -
Existing Aboveground Structures NA NA
Special Notes:
1 Based on conditions at exploration locations, may be greater at other locations
Close monitoring of the construction operations discussed herein will be critical in achieving the
design subgrade support. We therefore recommend that Terracon be retained to monitor this
portion of the work. This summary should be used in conjunction with the entire report for design
purposes. It should be recognized that details were not included or fully developed in this section,
and the report must be read in its entirety for a comprehensive understanding of the items contained
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herein. The section titled GENERAL COMMENTS should be read for an understanding of the report
limitations.
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GEOTECHNICAL ENGINEERING REPORT
TACO BELL NO. 312178
4225 NE 4TH ST
RENTON, WASHINGTON
Terracon Project No. 81175027
April 28, 2017
1.0 INTRODUCTION
This report presents the results of our geotechnical engineering services performed for the proposed
Taco Bell to be located at 4225 NE 4th St. in Renton, Washington. Our geotechnical engineering
scope of services for this project included the advancement of five exploratory soil borings to
depths ranging from approximately 11 to 21½ feet below existing site grades. The purpose of
these services is to provide information and geotechnical engineering recommendations
pertaining to:
n subsurface soil conditions n groundwater conditions
n earthwork n foundation design and construction
n floor slab design and construction n seismic considerations
n lateral earth pressure n pavement design and construction
2.0 PROJECT INFORMATION
2.1 Site Location and Description
ITEM DESCRIPTION
Location 4225 NE 4th St., Renton, King County, Washington
See Exhibit A-1 in Appendix A
Coordinates Latitude: 47.4882° N; Longitude: -122.1618° W
Existing Improvements Asphalt pavement and underground utilities.
Current ground cover Asphalt pavement and landscaping areas.
Existing topography Gentle slopes directed to five on-site stormwater catch basins.
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2.2 Project Description
ITEM DESCRIPTION
Site layout
Taco Bell restaurant structure in northeast quadrant of project site
with surrounding parking and drive-thru areas. Refer to the Site
and Exploration Diagram in Appendix A (Exhibit A-2) for plan view
of proposed layout.
Structures Taco Bell restaurant with an approximately 1,900 square foot
rectangular footprint.
Site grading Minor grading of the site will be required, except for removal of
existing fill soils.
Maximum loads
Interior Columns: 50 kips (assumed)
Wall: 3 kips per lineal foot (assumed)
Floor Slab: 150 psf (assumed)
Pavement Design Criteria
Parking and customer travel lanes
20 year design life
Light Duty Pavement: 50,000 ESAL1 maximum load (assumed)
Heavy Duty Pavement: 100,000 ESAL1 maximum load (assumed)
Concrete pavement for some traffic lanes and dumpster enclosures
1. ESAL = Equivalent 18,000-pound Single-Axle Load.
3.0 SUBSURFACE CONDITIONS
3.1 Published Geologic Conditions
The Geologic Map of the Renton Quadrangle, Washington, GQ-406 (Mullineaux, 1965), indicates
that near-surface deposits at the site are Vashon Stade Glacial Till (Qgt). This unit is described
as ground moraine deposits consisting of a relatively thin cap of ablation till over lodgment till,
both deposited by the Puget lobe of the Cordilleran ice sheet. All five borings agreed with
published conditions.
3.2 Soil Conditions
Soil conditions on the site were explored by advancing five borings to depths ranging between 11
and 21½ feet below existing site grades. Soil descriptions presented in this report are based on
the subsurface conditions encountered at specific exploration locations across the site. Variations
in subsurface conditions may exist between the exploration locations.
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Logs of the borings and a description of the field exploration procedures are presented in Appendix
A. The locations of the explorations on the site are shown on Exhibit A-2 in Appendix A. Stratification
boundaries on the logs represent the approximate locations of changes in soil types; in-situ, the
transition between materials may be gradual. Based on our borings and laboratory testing, a
generalized description of the site soil conditions is presented below.
Stratum
Approximate Depth to
Bottom of Stratum
(feet)
Material Description Consistency/
Density
1 3 – 7 Sand and gravel with variable silt
(FILL)
Loose to medium
dense
2 Full depth of borings Sand and gravel with variable silt
(GLACIAL TILL)
Medium dense to
Very Dense
3.3 Groundwater
Groundwater was observed while drilling at an approximate depth of 10 feet bgs in boring B-4 and
at 14 feet bgs in borings B-1 and B-2. The observed groundwater likely represents a perched
condition in which the vertical infiltration of groundwater is impeded by lower permeability layers
within the glacial till soils.
Groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff,
and water level in nearby bodies of water, as well as other factors not evident at the time the
borings were performed. Therefore, groundwater levels during construction or at other times in
the life of the structure may be higher or lower than the levels indicated on the boring logs.
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION
4.1 Geotechnical Considerations
Based on the information gathered through our subsurface investigation, utilization of conventional
shallow footings for ground support of the proposed improvements appears feasible. Proper
performance of conventional spread footings is contingent on meeting the specifications and
recommendations presented herein
Geotechnical engineering recommendations for foundation systems and other earth-connected
phases of the project are outlined below. The recommendations contained in this report are based
upon the use of data presented in the appendices, engineering analyses, and on our current
understanding of the proposed project.
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ASTM and Washington State Department of Transportation (WSDOT) specification codes cited
herein respectively refer to the current manual published by the American Society of Testing &
Materials and the 2014 edition of the WSDOT Standard Specifications for Road, Bridge, and
Municipal Construction (Publication M41-10).
n The existing fill at our boring locations beneath the proposed building footprint is on the
order of 6 feet in thickness (although locations of thicker fill may be encountered) and
should be completely removed in order to reduce the risk of unforeseen conditions that
may exist within these soils. If left in place, there is inherent risk for the owner that
compressible fill or unsuitable material within or buried by the fill may lead to potentially
damaging total and differential settlement.
n With the exception of boring B-4, the explorations conducted in areas proposed for parking
and drive-through lanes encountered existing fill soils in thicknesses on the order of 3 feet.
If total risk mitigation by way of complete removal and replacement of the existing fill is
undesired beneath proposed paved areas, we recommend scarification, moisture
conditioning, and recompaction of the upper 12-inches of subgrade for support of overlying
pavements in these areas.
If the risk of unforeseen conditions and possible unsuitable or compressible fill is deemed too
great by the owner, several options exist for reducing or eliminating the risk. Removal of the
existing fill and replacement with structural fill is a typical measure for mitigating adverse effects
of unsuitable fill soils. For the purposes of this report, we assume complete removal of the fill and
replacement with structural fill will be limited to the area under the proposed building pad. The
lateral extent of existing fill removal and replacement beyond the building pad footprint should be
at least two-thirds of the depth of excavation at the perimeter footing location. In addition to the
fill soils, any organic-rich soils should be removed and replaced in a similar manner. As an
alternative, we can provide recommendations for partial overexcavation and replacement of the
existing fill beneath the proposed building pad upon request, with the understanding that risk of
poor foundation performance is greater if the existing fill is not completely removed.
4.2 Earthwork
The following sections present recommendations for site preparation, excavation, subgrade
improvements, and placement of structural fill for the project. The recommendations presented
for design and construction of earth-supported elements, including foundations, slabs, and
pavements, are contingent upon following the recommendations outlined in this section.
Earthwork on the project should be observed and evaluated by Terracon. The evaluation of
earthwork should include observation and testing of structural fill, subgrade preparation,
foundation bearing soils, and other geotechnical conditions exposed during the construction of
the project.
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4.2.1 Site Preparation
Preparation for site grading and construction should begin with procedures intended to control
surface water runoff and erosion. Sump pits are often used as an effective method of
concentrating and containing surface water runoff which may, in turn, also prevent off-site
sediment migration and erosion. Site grading plans and practices should consider potential
impacts to adjacent properties and the public right-of-way.
4.2.2 Material Types
The suitability of soils used for structural fill depends primarily on their grain-size distribution and
moisture content when they are placed. As the fines content (that soil fraction passing the U.S.
No. 200 Sieve) increases, soils become more sensitive to small changes in moisture content.
Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted
to a firm, unyielding condition when the moisture content is more than 2 percentage points above
or below optimum. Optimum moisture content is the moisture content at which the maximum dry
density for the material is achieved in the laboratory following ASTM procedures.
Based on the grain-size characteristics of the existing fill encountered at our exploration locations,
the soils appear suitable for reuse as structural fill if placed in accordance with the
recommendations herein. Bulk samples of any excavated material may be obtained by a
Terracon representative during the construction phase for laboratory testing to determine the
suitability for fill applications within the building footprint.
If it becomes necessary to import structural fill we recommend using a well-graded sand and
gravel such as “Ballast” or “Gravel Borrow” per WSDOT: 9-03.9(1) and 9-03.14, respectively. For
combined structural fill and drainage purposes, a relatively clean and uniform angular material
such as “Crushed Surfacing Base Course” per WSDOT: 9-03.9(3) is preferable provided the fines
content is a maximum of 5 percent. Structural fill should consist of approved materials, free of
organic material, debris and particles larger than about 3 inches.
4.2.3 Compaction Requirements
Structural fill materials should be placed in horizontal lifts not exceeding about 8 inches in loose
thickness. We recommend that each lift then be thoroughly compacted with a mechanical
compactor to a uniform density of at least 95 percent, based on the modified Proctor test (ASTM
D 1557). Where light compaction equipment is used, as is typical within a few feet of retaining
walls and in utility trenches, the lift thickness may need to be reduced to achieve the desired
degree of compaction. Excavated soils that will be reused as structural fill should be protected
from rain and other factors to aid in preventing an increase in moisture content. Moisture contents
at the time of compaction should be within 2 percent of the optimum moisture content.
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4.2.4 Grading and Drainage
Adequate positive drainage of exposed subgrades should be provided during construction and
maintained throughout the life of the development to prevent an increase in moisture content of
the foundation and pavement subgrades and excavation backfill materials. Surface water
drainage should be controlled to prevent undermining of fill slopes and structures during and after
construction.
Roof gutters and downspouts should be routed into tightline pipes that discharge into a municipal
storm drain or other suitable location. Splash-blocks should also be considered below hose bibs
and water spigots.
4.2.5 Construction Considerations
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment. Although not encountered in our explorations, cobbles and
boulders may be present and should be anticipated.
Upon completion of filling and grading, care should be taken to maintain the subgrade moisture
content prior to construction of floor slabs and pavements. Construction traffic over the completed
subgrade should be avoided to the extent practical. The site should also be graded to prevent
ponding of surface water on the prepared subgrades or in excavations. If the subgrade should
become frozen, desiccated, saturated, or disturbed, the affected material should be removed or
these materials should be scarified, moisture conditioned, and recompacted prior to floor slab and
pavement construction and observed by Terracon.
Construction staging should provide drainage of surface water and precipitation away from the
building and pavement areas. Any water that collects over or adjacent to construction areas
should be promptly removed, along with any softened or disturbed soils. Surface water control in
the form of sloping surfaces, drainage ditches and trenches, and sump pits and pumps will be
important to avoid ponding and associated delays due to precipitation and seepage.
Groundwater was encountered at depths of 10 to 14 feet during our exploration in the borings that
extended to sufficient depth. Based on our understanding of the proposed development, we do
not expect groundwater to affect construction. If groundwater is encountered during construction,
some form of temporary dewatering may be required. Conventional dewatering methods, such as
pumping from sump pits, should likely be adequate for temporary removal of groundwater
encountered during excavation at the site.
Temporary excavations will probably be required during grading operations. The grading
contractor, by his contract, is usually responsible for designing and constructing stable, temporary
excavations and should shore, slope or bench the sides of the excavations as required to maintain
stability of both the excavation sides and bottom. All excavations should comply with applicable
local, state and federal safety regulations, including the current Occupational Health and Safety
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Administration (OSHA) Excavation and Trench Safety Standards. All excavations should be
sloped or braced as required by OSHA regulations to provide stability and safe working
conditions.
Construction site safety is the sole responsibility of the contractor who controls the means,
methods and sequencing of construction operations. Under no circumstances shall the
information provided herein be interpreted to mean that Terracon is assuming any responsibility
for construction site safety or the contractor's activities; such responsibility shall neither be implied
nor inferred.
4.3 Foundations
The site appears to be generally suitable for spread footings. Our on-site explorations
encountered approximately 3 to 7 feet of previously placed, undocumented fill (or probable fill) in
a loose to medium dense condition. Undocumented fill can be unpredictable by nature and can
contain deleterious materials that could degrade over time and cause settlement under the
building structure. To reduce the risk of excessive settlement, we recommend complete removal
of existing fill beneath the proposed building pad and replacement with compacted structural fill.
The lateral extent of existing fill removal and replacement for the building pad should be at least
two-thirds of the depth of excavation beyond the building pad footprint at the perimeter footing
location.
All overexcavated areas and excavations resulting from removal of the existing structures or
utilities on the site should be backfilled with structural fill in accordance with the relevant sections
of this report. In our opinion, after these overexcavations are completed, the proposed building
can be supported by a shallow, spread footing foundation system bearing on compacted structural
fill extending to suitable native soils. Design recommendations for shallow foundations for the
proposed structures are presented in the following paragraphs.
4.3.1 Design Recommendations
DESCRIPTION Column Wall
Net allowable bearing pressure for spread
footings bearing on dense to very dense
native soils
3,000 psf 3,000 psf
Net allowable bearing pressure for spread
footings bearing on structural fill extending to
dense to very dense native soils
3,000 psf 3,000 psf
Minimum dimensions 24 inches 18 inches
Minimum embedment below finished exterior
grade for perimeter footings 1 18 inches 18 inches
Minimum embedment below finished floor
grade for interior footings 12 inches 12 inches
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Approximate total settlement 2 <1 inch <1 inch
Estimated differential settlement 2 <½ inch between
columns <½ inch over 40 feet
Allowable coefficient of sliding friction3 0.35
Allowable passive pressure (Equivalent Fluid)3 300 pcf
1. For frost protection and to reduce the effects of seasonal moisture variations in the subgrade soils.
2. The foundation settlement will depend upon the variations within the subsurface soil profile, the
structural loading conditions, the embedment depth of the footings, the thickness of compacted fill,
and the quality of the earthwork operations.
3. Includes a factor of safety of 1.5
The allowable foundation bearing pressures apply to dead loads plus design live load conditions.
The design bearing pressure may be increased by one-third when considering dynamic loads that
include wind or seismic conditions. The weight of the foundation concrete below grade may be
neglected in dead load computations.
Footings, foundations, and masonry walls should be reinforced as necessary to reduce the
potential for distress caused by differential foundation movement. The use of joints at openings
or other discontinuities in masonry walls is recommended.
Foundation excavations should be observed by a Terracon representative. If the soil conditions
encountered differ from those presented in this report, supplemental recommendations will be
required.
We recommend that the building be encircled with a perimeter foundation drain to collect exterior
seepage water. This drain should consist of a 4-inch-diameter perforated pipe within an envelope
of pea gravel or washed rock, extending at least 6 inches on all sides of the pipe. The gravel
envelope should be wrapped with filter fabric (such as Mirafi 140N) to reduce the migration of
fines from the surrounding soils. The drain invert should be installed no more than 8 inches above
or below the base of the perimeter footings. The perimeter foundation drain should not be
connected to roof downspout drains and should be constructed to discharge into the site storm
water system or other appropriate outlet.
4.3.2 Construction Considerations
Even after the building subgrades are overexcavated and replaced with structural fill soils, as
recommended above, localized zones of unsuitable soils might be encountered in footing
excavations. In this case, the excavations should be extended deeper to suitable soils.
Overexcavation below footings should extend laterally beyond all edges of the footings at least 8
inches per foot of overexcavation depth below footing base elevation. The overexcavation should
then be backfilled up to the footing base elevation with well-graded granular material placed in
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lifts of 8 inches or less in loose thickness and compacted to at least 95 percent of the material's
maximum modified Proctor dry density (ASTM D-1557). The overexcavation and backfill
procedure is described in the figure below.
NOTE: Excavation shown vertical for convenience; excavations should be sloped as necessary for safety.
4.4 Floor Slabs
We recommend complete removal of existing fill encountered below the proposed building floor
slab, as described above for the foundation subgrades. Removed soils should be replaced with
structural fill placed and compacted in accordance with the Earthwork section of this report. A
subgrade prepared and tested as recommended in this report should provide adequate support
for lightly loaded floor slabs.
4.4.1 Design Recommendations
DESCRIPTION RECOMMENDATION
Interior floor system Slab-on-grade concrete.
Floor slab support Structural fill placed and compacted in accordance with the
Earthwork section of this report.
Base course/capillary break 4-inch compacted layer of free draining (less than 5 percent
passing the U.S. No. 200 sieve), uniform gravel
Modulus of subgrade reaction 150 pounds per square inch per in (psi/in) for point loading
conditions
1. Floor slabs should be structurally independent of any building footings or walls to reduce floor slab
cracking caused by differential movements between the slab and foundation. Narrower, turned-
down slab-on-grade foundations may be utilized at the approval of the structural engineer. The
slabs should be appropriately reinforced to support the proposed loads.
2. The base course serves as a capillary break layer, a drainage layer, a leveling layer, and a bearing
layer.
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We recommend subgrades be maintained at the proper moisture condition until floor slabs are
constructed. If the subgrade should become desiccated prior to construction of floor slabs, the
affected material should be removed or the materials scarified, moistened, and recompacted.
Upon completion of grading operations in the building areas, care should be taken to maintain the
recommended subgrade moisture content and density prior to construction of the building floor
slabs.
Where appropriate, saw-cut control joints should be placed in the slab to help control the location
and extent of cracking. For additional recommendations refer to the ACI Design Manual.
The use of a vapor retarder or barrier should be considered beneath concrete slab-on-grade floors
that will be covered with wood, tile, carpet or other moisture-sensitive or impervious coverings, or
when the slab will support equipment sensitive to moisture. When conditions warrant the use of
a vapor retarder, the slab designer and slab contractor should refer to ACI 302 and ACI 360 for
procedures and cautions regarding the use and placement of a vapor retarder/barrier.
4.4.2 Construction Considerations
On most project sites, the site grading is generally accomplished early in the construction phase.
However as construction proceeds, the subgrade may be disturbed due to utility excavations,
construction traffic, desiccation, rainfall, etc. As a result, the floor slab subgrade may not be suitable
for placement of the base course and concrete slab, and corrective action may be required.
All floor slab subgrade areas should be moisture conditioned and properly compacted to the
recommendations in this report and then thoroughly proofrolled with a loaded tandem-axle dump
truck or similar equipment prior to final grading and placement of the base course. Particular
attention should be paid to high traffic areas that were rutted and disturbed earlier and to areas
where backfilled trenches are located. Areas where unsuitable conditions are located should be
repaired by removing and replacing the affected material with properly compacted structural fill.
4.5 Seismic Considerations
DESCRIPTION VALUE
2015 International Building Code Site
Classification (IBC)1 D2
Site Latitude 47.4882° N
Site Longitude -122.1618° W
Ss Spectral Acceleration for a Short Period for
Site Class B 1.402g
S1Spectral Acceleration for a 1-Second Period
for Site Class B 0.526g
Fa Site Coefficient for a Short Period 1.000
FvSite Coefficient for a 1-Second Period 1.500
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DESCRIPTION VALUE
1 In general accordance with the 2015 International Building Code,and Table 20.3-1 of ASCE 7 –Chapter 20.Site Class is based
on the average characteristics of the upper 100 feet of the subsurface profile.
2 The 2015 International Building Code (IBC) and ASCE Publication 7 requires a site soil profile determination extending to a
depth of 100 feet for seismic site classification. The current scope was limited to explorations to a maximum depth of 21½ feet.
This seismic site class definition is based on the assumption that dense glacial till or better materials extend below the bottom of our
exploration.
We reviewed the USGS Earthquake Hazards Program Quaternary Faults and Folds Database
available online (http://earthquake.usgs.gov/hazards/qfaults/map/hazfault2014.html). The
nearest fault to the project site is the Seattle fault zone approximately 3 miles north of the project
site. The fault has a thrust sense of movement with an estimated upper bound moment magnitude
on the order of M7.0. According to this source, the fault has been mapped with south striking
features, and is in the slip rate category of between 0.2 and 1 mm/year. Based on the information
described above, we estimate that the risk associated with surface rupture at the site is low.
As part of our services, we conducted a preliminary evaluation of the risk of liquefaction at this
site. Based on our understanding of groundwater and geology at the site, it is our opinion that
the risk of liquefaction at the site is low because the native sandy gravels and gravelly sands are
dense to very dense. Therefore, the potential for seismic-related settlement above acceptable
values is also considered low, and possible seismic settlement is considered negligible provided
the existing fill soils are removed under the building pad.
4.6 Lateral Earth Pressures
The lateral earth pressure recommendations herein are applicable to the design of rigid retaining
walls subject to slight rotation, such as cantilever, or gravity type concrete walls. These
recommendations are not applicable to the design of modular block, geogrid-reinforced backfill walls
or rockeries.
Reinforced concrete walls with unbalanced backfill levels on opposite sides should be designed
for earth pressures at least equal to those indicated in the following table. Earth pressures will be
influenced by structural design of the walls, conditions of wall restraint, methods of construction
and/or compaction, and the strength of the materials being restrained. Two wall restraint
conditions are shown. “Active” earth pressure is commonly used for design of free-standing
cantilever retaining walls and assumes some wall deflection. The "at rest" condition assumes no
wall deflection. The recommended design lateral earth pressures do not include a factor of safety
and do not provide for possible hydrostatic pressure on the walls.
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 12
EARTH
PRESSURE
CONDITIONS
EARTH PRESSURE
COEFFICIENT
EQUIVALENT
FLUID DENSITY
(pcf)
SURCHARGE
PRESSURE, p1
(psf)
EARTH
PRESSURE, p2
(psf)
Active (Ka)0.28 35 (0.28)S (35)H
At-Rest (Ko)0.44 55 (0.44)S (55)H
Passive (Kp)3.54 300 ------
Applicable conditions to the above include:
n For active earth pressure, wall must rotate about base, with top lateral movements of about
0.002 H to 0.004 H, where H is wall height
n For passive earth pressure to develop, wall must move horizontally to mobilize resistance,
therefore a factor of safety of 1.5 has been applied to reduce required motions
n Uniform surcharge, where S is surcharge pressure in psf
n Wall backfill weight a maximum of 125 pcf
n Horizontal finished grade compacted to 95 percent of modified Proctor maximum dry density
n Loading from heavy compaction equipment not included
n No hydrostatic pressures acting on wall
n No dynamic loading
n No safety factor included in active or at-rest soil parameters
n Ignore passive pressure in frost zone
To account for increased lateral pressures on foundation and retaining walls due to earthquake
motions, we recommend uniformly distributed pressures of 7H and 12H in pounds per square foot
(rectangular distribution) to be applied to yielding and non-yielding walls, respectively. These
pressures are in addition to the static pressures presented above.
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 13
Backfill placed against walls should consist of granular structural fill. For these pressures to be valid,
the structural fill must extend out from the base of the wall at an angle of at least 45 and 60 degrees
from vertical for the active and passive cases, respectively. To calculate the resistance to sliding, a
value of 0.5 should be used as the ultimate coefficient of friction between the footing and the
underlying soil.
To aid in reducing the potential for hydrostatic pressure behind walls, we recommend placing a
gravel curtain drain against the back of the wall, with a perforated collection pipe leading to a
reliable discharge. The gravel curtain drain should be separated from the silty site soils with a
Mirafi 140N filter fabric, or equivalent. If adequate drainage is not possible, then combined
hydrostatic and lateral earth pressures should be calculated for granular backfill using an
equivalent fluid weighing 80 and 90 pcf for active and at-rest conditions, respectively. These
pressures do not include the influence of surcharge, equipment or floor loading, which should be
added where appropriate. Heavy equipment should not operate within a distance closer than the
exposed height of retaining walls to prevent lateral pressures more than those provided.
4.7 Pavements
Explorations in the areas of proposed paved parking lots and drive lanes encountered fill soils to a
depth of approximately 3 to 7 feet below existing site grades, although locations of deeper fill may
exist. Provided the owner is willing to accept the risk of unpredictable settlement response of the
existing fill under pavement sections, the existing fill may provide reasonable support for
pavements. However, we recommend limiting risk mitigation measures by removal of the existing
pavement section down to the planned subgrade elevation, followed by scarification, moisture
conditioning, and recompaction of the underlying 12-inches of fill. Unsuitable fill exposed during
this process should be overexcavated and backfilled with compacted structural fill. Based on the
results of our explorations, existing fill soils are generally in a loose to medium dense condition and
represent a low to moderate risk of excessive settlements due to traffic loading after completion of
the recommended improvements, though areas of unsuitable or compressible fill may be present
within the fill areas that were not observed in our explorations.
4.7.1 Subgrade Preparation
On most project sites, the site grading is accomplished relatively early in the construction phase.
Fills are placed and compacted in a uniform manner. However, as construction proceeds,
excavations are made into these areas, rainfall and surface water saturates some areas, heavy
traffic from concrete trucks and other construction vehicles disturbs the subgrade, and many surface
irregularities are filled in with loose soils to temporarily improve trafficability. As a result, the
pavement subgrades, initially prepared early in the project, should be carefully evaluated as the
time for pavement construction approaches.
We recommend that the moisture content and density of the top 12 inches of the subgrade be
evaluated and that the pavement subgrades be proofrolled within two days prior to commencement
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 14
of actual paving operations. Areas not in compliance with the required ranges of moisture or density
should be moisture conditioned and recompacted. Particular attention should be paid to high traffic
areas that were rutted and disturbed earlier and to areas where backfilled trenches are located.
Areas where unsuitable conditions are located should be repaired by removing and replacing the
materials with properly compacted structural fills. If a significant precipitation event occurs after the
evaluation or if the surface becomes disturbed, the subgrade should be reviewed by qualified
personnel immediately prior to paving. The subgrade should be in its finished form at the time of
the final review.
4.7.2 Design Considerations
We anticipate that traffic loads will be produced primarily by automobile traffic and by occasional
delivery and trash-removal trucks. The thickness of pavements subjected to heavy truck traffic
should be determined using expected traffic volumes, vehicle types, and vehicle loads and should
be in accordance with local, city or county ordinances.
Pavement thickness were determined using AASHTO methods based on assumed values of
maximum ESAL loading of 50,000 (ESAL = equivalent 18-kip single axle load) for standard duty car
and parking areas over a 20-year design life. For heavy duty truck traffic areas, we used an
assumed traffic loading of 100,000 ESALs for use in our analysis.
The minimum pavement sections were determined based on the laboratory test results and post-
construction traffic loading conditions. These pavement sections do not account for heavy
construction traffic during development. A partially constructed structural section may be
subjected to heavy construction traffic that can result in pavement deterioration and premature
failure. Our experience indicates that this pavement construction practice can result in pavements
that will not perform as intended. Considering this information, several alternatives are available
to mitigate the impact of heavy construction traffic on the pavement construction. These include
using thicker sections to account for the construction traffic; using some method of soil
stabilization to improve the support characteristics of the pavement subgrade; routing heavy
construction traffic around paved areas; or delaying paving operations until as near the end of
construction as is feasible.
Pavement performance is affected by its surroundings. In addition to providing preventive
maintenance, the civil engineer should consider the following recommendations in the design and
layout of pavements:
n Final grade adjacent to parking lots and drives should slope down from pavement edges at a
minimum 2%;
n The subgrade and the pavement surface should have a minimum ¼ inch per foot slope to
promote proper surface drainage;
n Install pavement drainage surrounding areas anticipated for frequent wetting (e.g., landscaping
areas, etc.);
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 15
n Install joint sealant and seal cracks immediately;
n Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to
subgrade soils, and;
n Place compacted, low permeability backfill against the exterior side of curb and gutter
Our scope did not include collecting a bulk sample and determining the California Bearing Ratio
(CBR). Our pavement design was conducted using an assumed CBR value of 10 percent and
assuming that the upper foot of the pavement subgrade is thoroughly compacted to at least 95
percent of the modified Proctor density within 2 percent of its optimum moisture, as recommended
in the earthwork section of this report.
4.7.3 Estimates of Minimum Pavement Thickness
The minimum pavement component thicknesses listed below should be used as a guide for
pavement sections at the site for the traffic classifications stated herein. These recommendations
assume a 20-year pavement design life. If pavement frequencies or loads will be different than
that assumed, Terracon should be contacted and allowed to review these pavement sections.
The minimum pavement thickness is governed by the Yum Standard Site Paving Plan provided
to Terracon on January 20, 2015.
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 16
MINIMUM STANDARD-DUTY PAVEMENT SECTION FOR CAR-ONLY AREAS
Layer Thickness
(inches)
Compaction/Material
Specification
Compacted Structural Fill
or Subgrade -95% of Modified Proctor MDD, -2 to
+2% OMC
Crushed Aggregate Base 6 WSDOT: 9-03.9(3) Base Course
Asphalt Surface Course 3 WSDOT: 9-03.8(2) ¾-inch HMA
WSDOT: 9-03.8(6) ¾-inch Aggregate
Total Pavement Section 9
MINIMUM HEAVY DUTY-PAVEMENT SECTION FOR TRUCK AREAS
Layer Thickness
(inches)
Compaction/Material
Specification
Compacted Structural Fill
or Subgrade -95% of Modified Proctor MDD, -2 to
+2% OMC
Crushed Aggregate Base 6 WSDOT: 9-03.9(3) Base Course
Asphalt Surface Course 4 WSDOT: 9-03.8(2) ¾-inch HMA
WSDOT: 9-03.8(6) ¾-inch Aggregate
Total Pavement Section 10
The abbreviations MDD, OMC, and HMA in the tables above refer to Maximum Dry Density, Optimum Moisture
Content, and Hot Mix Asphalt, respectively.
The graded crushed aggregate base should be compacted to a minimum of 95 percent of the
material’s modified Proctor (ASTM D-1557, Method C) maximum dry density. Where base course
thickness exceeds 8 inches, the material should be placed and compacted in two or more lifts of
equal thickness.
We recommend that a Portland cement concrete pavement (PCC) be utilized in entrance and exit
sections, dumpster pads, drive-thru, or other areas where extensive wheel maneuvering or
repeated loading are expected. The dumpster pad should be large enough to support the wheels
of the truck which will bear the load of the dumpster. We recommend a minimum of 6 inches of
CCP underlain by 4 inches of crushed aggregate base. Although not required for structural
support, the base course layer is recommended to help reduce potential for slab curl, shrinkage
cracking, and subgrade “pumping” through joints. Proper joint spacing will also be required to
prevent excessive slab curling and shrinkage cracking. All joints should be sealed to prevent
entry of foreign material and dowelled where necessary for load transfer.
Portland cement concrete should be designed with proper air-entrainment and have a minimum
compressive strength of 4,000 psi after 28 days of laboratory curing. Adequate reinforcement and
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 17
number of longitudinal and transverse control joints should be placed in the rigid pavement in
accordance with ACI requirements. The joints should be sealed as soon as possible (in
accordance with sealant manufacturer’s instructions) to minimize water infiltration into the soil.
4.7.4 Pavement Drainage
Pavements should be sloped to provide rapid drainage of surface water. Water allowed to pond on
or adjacent to the pavements could saturate the subgrade and contribute to premature pavement
deterioration. In addition, the pavement subgrade should be graded to provide positive drainage
within the crushed aggregate base section.
We recommend drainage be included at the bottom of the crushed aggregate base layer at the
storm structures to aid in removing water that may enter this layer. Drainage could consist of small
diameter weep holes excavated around the perimeter of the storm structures. The weep holes
should be excavated at the elevation of the crushed aggregate base and soil interface. The
excavation should be covered with crushed aggregate which is encompassed in Mirafi 140NL or
approved equivalent which will aid in reducing fines from entering the storm system.
4.7.5 Pavement Maintenance
The pavement sections provided in this report represent minimum recommended thicknesses.
Therefore preventive maintenance should be planned and provided for through an on-going
pavement management program. Preventive maintenance activities are intended to slow the rate
of pavement deterioration, and to preserve the pavement investment. Preventive maintenance
consists of both localized maintenance (e.g., crack and joint sealing and patching) and global
maintenance (e.g., surface sealing). Preventive maintenance is usually the first priority when
implementing a planned pavement maintenance program and provides the highest return on
investment for pavements. Prior to implementing any maintenance, additional engineering
observation is recommended to determine the type and extent of preventive maintenance. Even
with periodic maintenance, some movements and related cracking may still occur and repairs may
be required.
5.0 GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so comments can
be made regarding interpretation and implementation of our geotechnical recommendations in the
design and specifications. Terracon also should be retained to provide observation and testing
services during grading, excavation, foundation construction and other earth-related construction
phases of the project.
The analysis and recommendations presented in this report are based upon the data obtained
from the borings performed at the indicated locations and from other information discussed in this
report. This report does not reflect variations that may occur between borings, across the site, or
due to the modifying effects of construction or weather. The nature and extent of such variations
Geotechnical Engineering Report
Taco Bell #312178 ■Renton, Washington
April 28, 2017■Terracon Project No. 81175027
Responsive ■Resourceful ■Reliable 18
may not become evident until during or after construction. If variations appear, we should be
immediately notified so that further evaluation and supplemental recommendations can be
provided.
The scope of services for this project does not include either specifically or by implication any
environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or
prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the
potential for such contamination or pollution, other studies should be undertaken.
This report has been prepared for the exclusive use of Taco Bell of America, LLC for specific
application to the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranties, either express or implied, are intended or
made. Site safety, excavation support, and dewatering requirements are the responsibility of
others. In the event that changes in the nature, design, or location of the project as outlined in
this report are planned, the conclusions and recommendations contained in this report shall not
be considered valid unless Terracon reviews the changes and either verifies or modifies the
conclusions of this report in writing.
APPENDIX A
FIELD EXPLORATION
N
Project Mngr:
Approved By:
Checked By:
Drawn By:
Project No.
Scale:
Date:
File No.
EXHIBIT
Consulting Engineers and Scientists
21905 64th Avenue W., Ste 100 Mountlake Terrace, WA 98043
FAX. (425) 771-3549PH. (425) 771-3304
SITE AND EXPLORATION PLAN
Renton Taco Bell #312178
4225 NE 4th St
Renton, Washington A-1
81175027
AS SHOWN
Exhibit A-1.dwg
April 2017
BCO
BCO
RWS
DAB
Basemap PDF file provided by Google Maps and modified by Terracon.
Map data 2016 Google
APPROXIMATE SITE
LOCATION
LEGEND:
N
Project Mngr:
Approved By:
Checked By:
Drawn By:
Project No.
Scale:
Date:
File No.
EXHIBIT
Consulting Engineers and Scientists
21905 64th Avenue W., Ste 100 Mountlake Terrace, WA 98043
FAX. (425) 771-3549PH. (425) 771-3304
SITE AND EXPLORATION PLAN
Renton Taco Bell #312178
4225 NE 4th St
Renton, Washington A-2
81175027
AS SHOWN
Exhibit A-2.dwg
April 2017
BCO
BCO
RWS
DAB
Basemap PDF file provided by Client and modified by Terracon.
Map data 2016 Google
BORING NUMBER AND
APPROXIMATE LOCATION
LEGEND:
B-1
B-5
B-4
B-3
B-1
B-2
SCALE IN FEET
040 10 4020
5-5-6
N=11
6-8-11N=19
N=50/6"
13-8-11N=19
14, 50/6"
N=50/6"
18, 50/5"N=50/6"
5.0
14.0
20.9
POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), brown, medium dense,moist (FILL)
SANDY GRAVEL WITH SILT (GP-GM), brown to orange, medium dense, weathered, moist(GLACIAL TILL)
hammer likely driving on large gravel or cobble
trace silt, moist to wet
SILTY GRAVELLY SAND (SM), gray-brown, very dense, fresh, wet
Boring Terminated at 20.9 Feet
7
3
5
6GRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175027.GPJ TERRACON_DATATEMPLATE.GDT 4/28/17FIELD TESTRESULTSDEPTH
LOCATION
Latitude: 47.488755° Longitude: -122.161182°
See Exhibit A-2
PERCENT FINESWATERCONTENT (%)SAMPLE TYPEWATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15
20
4225 NE 4th St.
Renton, WA
SITE:
Page 1 of 1
Advancement Method:Hollow Stem Auger
Abandonment Method:Backfilled with Auger Cuttings and/or Bentonite
Notes:
Project No.: 81175027
Drill Rig: D-120
Boring Started: 3/30/2017
BORING LOG NO. B-1
Taco Bell of America, LLCCLIENT:1 Glen Bell Way MD #534
Driller: Holocene
Boring Completed: 3/30/2017
Exhibit:
Pulcheon, Steve
A-3
See Exhibit A-3 for description of fieldprocedures.
See Appendix B for description of laboratoryprocedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.Elevations measured in the field
PROJECT: Taco Bell Site #312178 Renton
21905 64th Ave W Ste 100Mountlake Terrace, WA
While drilling
WATER LEVEL OBSERVATIONS
3-5-4
N=9
5-5-19N=24
11-25-32
N=57
25-30-41N=71
N=50/5"
18, 50/5"N=50/5"
6.0
20.9
SANDY GRAVEL (GP), trace silt, brown, loose, moist(FILL)
SANDY GRAVEL WITH SILT (GP), gray-brown, very dense, moist(GLACIAL TILL)
becomes wet
Boring Terminated at 20.9 Feet
45
14GRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175027.GPJ TERRACON_DATATEMPLATE.GDT 4/28/17FIELD TESTRESULTSDEPTH
LOCATION
Latitude: 47.488387° Longitude: -122.16186°
See Exhibit A-2
PERCENT FINESWATERCONTENT (%)SAMPLE TYPEWATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15
20
4225 NE 4th St.
Renton, WA
SITE:
Page 1 of 1
Advancement Method:Hollow Stem Auger
Abandonment Method:Backfilled with Auger Cuttings and/or Bentonite
Notes:
Project No.: 81175027
Drill Rig: D-120
Boring Started: 3/30/2017
BORING LOG NO. B-2
Taco Bell of America, LLCCLIENT:1 Glen Bell Way MD #534
Driller: Holocene
Boring Completed: 3/30/2017
Exhibit:
Pulcheon, Steve
A-4
See Exhibit A-3 for description of fieldprocedures.
See Appendix B for description of laboratoryprocedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.Elevations measured in the field
PROJECT: Taco Bell Site #312178 Renton
21905 64th Ave W Ste 100Mountlake Terrace, WA
While drilling
WATER LEVEL OBSERVATIONS
18, 50/5"N=50/5"
13-18-30N=48
11-17-23
N=40
18-20-19N=39
3.5
11.5
SANDY GRAVEL (GP), trace silt, brown, loose, moist(FILL)
GRAVELLY SAND (SP), trace silt, gray-brown, dense, weathered, moist
(GLACIAL TILL)
Boring Terminated at 11.5 FeetGRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175027.GPJ TERRACON_DATATEMPLATE.GDT 4/28/17FIELD TESTRESULTSDEPTH
LOCATION
Latitude: 47.488222° Longitude: -122.161758°
See Exhibit A-2
PERCENT FINESWATERCONTENT (%)SAMPLE TYPEWATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
4225 NE 4th St.
Renton, WA
SITE:
Page 1 of 1
Advancement Method:Hollow Stem Auger
Abandonment Method:Backfilled with Auger Cuttings and/or Bentonite
Notes:
Project No.: 81175027
Drill Rig: D-120
Boring Started: 3/30/2017
BORING LOG NO. B-3
Taco Bell of America, LLCCLIENT:1 Glen Bell Way MD #534
Driller: Holocene
Boring Completed: 3/30/2017
Exhibit:
Pulcheon, Steve
A-5
See Exhibit A-3 for description of fieldprocedures.
See Appendix B for description of laboratoryprocedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.Elevations measured in the field
PROJECT: Taco Bell Site #312178 Renton
21905 64th Ave W Ste 100Mountlake Terrace, WA
Groundwater not encountered
WATER LEVEL OBSERVATIONS
18,25,50/2"N=75/8"
9-13-8N=21
8-24-32
N=56
18,50/6"
N=50/6"
7.0
11.0
SANDY GRAVEL WITH SILT (GP-GM), brown, medium dense to dense, moist, blowcountslikely overstated (FILL)
GRAVELLY SAND WITH SILT (SP-SM), gray-brown, very dense, moist to wet
(GLACIAL TILL)
Boring Terminated at 11 Feet
6GRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175027.GPJ TERRACON_DATATEMPLATE.GDT 4/28/17FIELD TESTRESULTSDEPTH
LOCATION
Latitude: 47.4881° Longitude: -122.16213°
See Exhibit A-2
PERCENT FINESWATERCONTENT (%)SAMPLE TYPEWATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
4225 NE 4th St.
Renton, WA
SITE:
Page 1 of 1
Advancement Method:Hollow Stem Auger
Abandonment Method:Backfilled with Auger Cuttings and/or Bentonite
Notes:
Project No.: 81175027
Drill Rig: D-120
Boring Started: 3/30/2017
BORING LOG NO. B-4
Taco Bell of America, LLCCLIENT:1 Glen Bell Way MD #534
Driller: Holocene
Boring Completed: 3/30/2017
Exhibit:
Pulcheon, Steve
A-6
See Exhibit A-3 for description of fieldprocedures.
See Appendix B for description of laboratoryprocedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.Elevations measured in the field
PROJECT: Taco Bell Site #312178 Renton
21905 64th Ave W Ste 100Mountlake Terrace, WA
While drilling
WATER LEVEL OBSERVATIONS
8-22-30
N=52
N=50/6"
8-18-32
N=50
8,50/5"
1.0
3.0
8.0
10.9
POORLY GRADED GRAVEL (GP), gray, drain rock from stockpile, dry(FILL)
GRAVELLY SAND (SP), trace silt, dark gray-brown, medium dense to dense, blowcounts
likely overstated
GRAVELLY SAND WITH SILT (SP-SM), gray-brown, very dense, weathered, moist to wet
(GLACIAL TILL)
SANDY GRAVEL WITH SILT (GP-GM), gray-brown, very dense, fresh, wet
Boring Terminated at 10.9 Feet
611GRAPHIC LOGHammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175027.GPJ TERRACON_DATATEMPLATE.GDT 4/28/17FIELD TESTRESULTSDEPTH
LOCATION
Latitude: 47.488201° Longitude: -122.162324°
See Exhibit A-2
PERCENT FINESWATERCONTENT (%)SAMPLE TYPEWATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
4225 NE 4th St.
Renton, WA
SITE:
Page 1 of 1
Advancement Method:Hollow Stem Auger
Abandonment Method:Backfilled with Auger Cuttings and/or Bentonite
Notes:
Project No.: 81175027
Drill Rig: D-120
Boring Started: 3/30/2017
BORING LOG NO. B-5
Taco Bell of America, LLCCLIENT:1 Glen Bell Way MD #534
Driller: Holocene
Boring Completed: 3/30/2017
Exhibit:
Pulcheon, Steve
A-7
See Exhibit A-3 for description of fieldprocedures.
See Appendix B for description of laboratoryprocedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.Elevations measured in the field
PROJECT: Taco Bell Site #312178 Renton
21905 64th Ave W Ste 100Mountlake Terrace, WA
Groundwater not encountered
WATER LEVEL OBSERVATIONS
Responsive ■Resourceful ■Reliable Exhibit A-4
Field Exploration Description
The subsurface exploration consisted of drilling and sampling five (5) borings at the site to depths
ranging from about 11 to 21½ feet below existing grade. The boring locations were laid out by
Terracon personnel and distances to existing site features determined with a measuring wheel.
The locations of the borings should be considered accurate only to the degree implied by the
means and methods used to define them.
The borings were drilled with a truck-mounted drill rig using hollow stem augers to advance the
boreholes. Representative soil samples were obtained by the split-barrel sampling procedure at
2½ to 5-foot intervals. In the standard penetration test (SPT) split-barrel sampling procedure, the
number of blows required to advance a standard 2-inch O.D. split-barrel sampler the last 12
inches of the typical total 18-inch penetration by means of a 140-pound hammer with a free fall of
30 inches, is the standard penetration resistance value (N). These values are indicted on the
borings logs at the depths of occurrence. This value is used to estimate the in-situ relative density
of cohesionless soils and the consistency of cohesive soils. The sampling depths and penetration
distance, plus the standard penetration resistance values, are shown on the boring logs. The
samples were sealed and taken to the laboratory for testing and classification.
An automatic SPT hammer was used to advance the split-barrel sampler in the borings performed
on this site. A greater efficiency is typically achieved with the automatic hammer compared to the
conventional safety hammer operated with a cathead and rope. Published correlations between
the SPT values and soil properties are based on the lower efficiency cathead and rope method.
This higher efficiency affects the standard penetration resistance blow count (N) value by
increasing the penetration per hammer blow over what would obtained using the cathead and
rope method. The effect of the automatic hammer's efficiency has been considered in the
interpretation and analysis of the subsurface information for this report.
Field logs of each boring were prepared by the geologist on site. These logs included visual
classifications of the materials encountered during drilling as well as the geologist’s interpretation
of the subsurface conditions between samples. Final boring logs included with this report
represent an interpretation of the field logs and include modifications based on laboratory
observation and tests of the samples. Samples were screened in the field using a Photoionization
Detector (PID) and elevated values (> 10 ppm) were not encountered.
The samples were classified in the laboratory based on visual observation, texture and plasticity.
The descriptions of the soils indicated on the boring logs are in general accordance with the
enclosed General Notes and the Unified Soil Classification System contained in Appendix C.
Estimated group symbols according to the Unified Soil Classification System are given on the
boring logs. A brief description of this classification system is attached to this report.
APPENDIX B
LABORATORY TESTING
Geotechnical Engineering Report
Taco Bell #312178 ■Auburn, Washington
April 28, 2017■Terracon Project No. 81145070
Responsive ■Resourceful ■Reliable Exhibit B-1
Laboratory Testing
As part of the testing program, all samples were examined in the laboratory by experienced
personnel and classified in accordance with the attached General Notes and the Unified Soil
Classification System based on the texture and plasticity of the soils. The group symbol for the
Unified Soil Classification System is shown in the appropriate column on the boring logs and a
brief description of the classification system is included with this report in the Appendix.
At that time, the field descriptions were confirmed or modified as necessary and an applicable
laboratory testing program was formulated to assess index properties of the subsurface materials.
Laboratory tests were conducted on selected soil samples and the test results are presented in
this appendix. The laboratory test results were used for the geotechnical engineering analyses,
and the development of foundation and earthwork recommendations. Laboratory tests were
performed in general accordance with the applicable ASTM, local or other accepted standards.
Laboratory testing of selected soil samples consisted of the following tests:
n Moisture Content Determinations (ASTM D2216)
n Grain Size Distribution (ASTM D422)
Procedural standards noted above are for reference to methodology in general. In some cases
variations to methods are applied as a result of local practice or professional judgment.
This appendix presents the results of the grain size distribution testing and the boring logs in
Appendix A contain the moisture content determination results.
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
B-1
B-1
B-2
B-5
1.627
2.861
1.318
0.791
7.436
8.608
5.725
4.155
25
25
25
19
6 16 20 30 40 501.5 2006810
52.5
60.8
45.7
37.5
0.173
0.586
0.329
0.154
14
LL PL PI
413/4 1/2 60
fine
B-1
B-1
B-2
B-5
43.09
14.68
17.40
26.94
GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTcoarse fine
HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
2.06
1.62
0.92
0.98
D100
Cc Cu
SILT OR CLAY
4
%Sand%GravelD30D10
5 - 6.5
10 - 11.5
7.5 - 9
2.5 - 4
3/8 3 10014032
COBBLES GRAVEL SAND
40.3
36.1
50.3
56.4
D60
coarse medium
Boring ID Depth
Boring ID Depth
GRAIN SIZE DISTRIBUTION
5 - 6.5
10 - 11.5
7.5 - 9
2.5 - 4
ASTM D422 / ASTM C136
WC (%)USCS Classification
WELL-GRADED GRAVEL with SAND and SILT (GW-GM)
WELL-GRADED GRAVEL with SAND (GW)
POORLY GRADED SAND with GRAVEL (SP)
POORLY GRADED SAND with GRAVEL (SP)
%Fines%Silt
7.2
3.1
4.0
6.2
%Clay
PROJECT NUMBER: 81175027PROJECT: Taco Bell Site #312178 Renton
SITE: 4225 NE 4th St. Renton, WA CLIENT: Taco Bell of America, LLC 1 Glen Bell Way MD #534
EXHIBIT: B-2
21905 64th Ave W Ste 100Mountlake Terrace, WA
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 81175027.GPJ TERRACON2015.GDT 4/24/17
Responsive ■Resourceful ■Reliable Exhibit A-4
APPENDIX C
SUPPORTING DOCUMENTS
Exhibit C-1
GENERAL NOTES
DRILLING & SAMPLING SYMBOLS:
SS:Split Spoon – 1-3/8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger
ST:Thin-Walled Tube - 3" O.D., unless otherwise noted PA: Power Auger
RS:Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger
DB:Diamond Bit Coring - 4", N, B RB: Rock Bit
BS:Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary
The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch
penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”.
WATER LEVEL MEASUREMENT SYMBOLS:
WL:Water Level WS:While Sampling N/E: Not Encountered
WCI: Wet Cave in WD:While Drilling
DCI:Dry Cave in BCR:Before Casing Removal
AB:After Boring ACR:After Casing Removal
Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other
times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In
low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations.
DESCRIPTIVE SOIL CLASSIFICATION:Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils
have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand.
Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are
plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may
be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the
basis of their in-place relative density and fine-grained soils on the basis of their consistency.
CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS
Unconfined
Compressive
Strength, Qu, psf
Standard Penetration
or N-value (SS)
Blows/Ft.
Consistency
Standard Penetration
or N-value (SS)
Blows/Ft.
Ring Sampler (RS)
Blows/Ft.Relative Density
< 500 0-1 Very Soft 0 – 3 0-6 Very Loose
500 – 1,000 2-3 Soft 4 – 9 7-18 Loose
1,001 – 2,000 4-6 Medium Stiff 10 – 29 19-58 Medium Dense
2,001 – 4,000 7-12 Stiff 30 – 49 59-98 Dense
4,001 – 8,000 13-26 Very Stiff 50+99+Very Dense
8,000+26+Hard
RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY
Descriptive Term(s)of other
Constituents
Percent of
Dry Weight
Major Component
of Sample Particle Size
Trace < 15 Boulders Over 12 in. (300mm)
With 15 – 30 Cobbles 12 in. to 3 in. (300mm to 75 mm)
Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm)
Sand
Silt or Clay
#4 to #200 sieve (4.75mm to 0.075mm)
Passing #200 Sieve (0.075mm)
RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION
Descriptive Term(s) of other
Constituents
Percent of
Dry Weight Term Plasticity
Index
Trace < 5 Non-plastic 0
With 5 – 12 Low 1-10
Modifier > 12 Medium 11-30
High 30+
Exhibit C-2
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A
Soil Classification
Group
Symbol Group Name B
Coarse Grained Soils:
More than 50% retained on
No. 200 sieve
Gravels:
More than 50% of
coarse fraction retained
on No. 4 sieve
Clean Gravels:
Less than 5% fines C
Cu ‡ 4 and 1 £ Cc £ 3 E GW Well-graded gravel F
Cu < 4 and/or 1 > Cc > 3 E GP Poorly graded gravel F
Gravels with Fines:
More than 12% fines C
Fines classify as ML or MH GM Silty gravel F,G,H
Fines classify as CL or CH GC Clayey gravel F,G,H
Sands:
50% or more of coarse
fraction passes No. 4
sieve
Clean Sands:
Less than 5% fines D
Cu ‡ 6 and 1 £ Cc £ 3 E SW Well-graded sand I
Cu < 6 and/or 1 > Cc > 3 E SP Poorly graded sand I
Sands with Fines:
More than 12% fines D
Fines classify as ML or MH SM Silty sand G,H,I
Fines classify as CL or CH SC Clayey sand G,H,I
Fine-Grained Soils:
50% or more passes the
No. 200 sieve
Silts and Clays:
Liquid limit less than 50
Inorganic:PI > 7 and plots on or above “A” line J CL Lean clay K,L,M
PI < 4 or plots below “A” line J ML Silt K,L,M
Organic:Liquid limit - oven dried < 0.75 OL Organic clay K,L,M,N
Liquid limit - not dried Organic silt K,L,M,O
Silts and Clays:
Liquid limit 50 or more
Inorganic:PI plots on or above “A” line CH Fat clay K,L,M
PI plots below “A” line MH Elastic Silt K,L,M
Organic:Liquid limit - oven dried < 0.75 OH Organic clay K,L,M,P
Liquid limit - not dried Organic silt K,L,M,Q
Highly organic soils:Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-in. (75-mm) sieveBIf field sample contained cobbles or boulders, or both, add “with
cobbles or boulders, or both” to group name.
C Gravels with 5 to 12% fines require dual symbols: GW-GM well-
graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly
graded gravel with silt, GP-GC poorly graded gravel with clay.D Sands with 5 to 12% fines require dual symbols: SW-SM well-
graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly
graded sand with silt, SP-SC poorly graded sand with clay
E Cu = D60/D10 Cc =6010
2
30
DxD
)(D
F If soil contains ‡ 15% sand, add “with sand” to group name.G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.
H If fines are organic, add “with organic fines” to group name.
I If soil contains ‡ 15% gravel, add “with gravel” to group name.
J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.K If soil contains 15 to 29% plus No. 200, add “with sand” or “with
gravel,” whichever is predominant.
L If soil contains ‡ 30% plus No. 200 predominantly sand, add
“sandy” to group name.
M If soil contains ‡ 30% plus No. 200, predominantly gravel, add
“gravelly” to group name.
N PI ‡ 4 and plots on or above “A” line.
O PI < 4 or plots below “A” line.
P PI plots on or above “A” line.
Q PI plots below “A” line.