HomeMy WebLinkAboutMiscGeotechnical Engineering Report
3616 Lincoln Avenue NE
Renton, Washington
P/N 3345700215
Submitted to:
Encompass Engineering and Surveying
Attn: Timothy Collins
165 NE Juniper St, Suite 201
Issaquah, Washington 98027
Submitted by:
E3RA, Inc.
PO Box44840
Tacoma, Washington 98448
(253) 537-9400
March 20, 2015
Project No. T15023
11 1 \' 9
Ju1,J 2 . 20'1' ,,
TABLE OF CONTENTS
Page No.
1.0 SITE AND PROJECT DESCRIPTION ................................................................................... 1
2.0 EXPLORATORY METHODS ........................................................................................ 2
2.1 Test Pit Procedures ............................................................................................. 2
2.2 Test Hole Procedures............................ . .. 3
3.0 SITE CONDITIONS ................................................................................................................. 3
3.1 Surface Conditions ....................................................................................................... 3
3.2 Soil Conditions ............................................................................................................. 3
3.3 Groundwater Conditions .............................................................................................. 4
3.4 Seismic Conditions ...................................................................................................... 4
3.5 Liquefaction Potential .................................................................................................. 4
3.6 Infiltration Conditions and Infiltration Rate ................................................................... 4
4.0 CONCLUSIONS AND RECOMMENDATIONS ....................................................................... 5
4.1 Site Preparation ........................................................................................................... 6
4.2 Spread Footings.......................................................... . ............................ 8
4.3 Slab-On-Grade Floors .................................................................................................. 9
4.4 Drainage Systems........ . ................................................................................ 9
4.5 Asphalt Pavement .................................................................................................... 10
4.6 Structural Fill . . . ............................................................................................. 11
5.0 RECOMMENDED ADDITIONAL SERVICES ........................................................................ 12
6.0 CLOSURE................................................................................................ . ....... 12
List of Tables
Table 1. Approximate Locations and Depths of Explorations ..
Table 2. Laboratory Test Results for Non-organic Onsite Soils ..................... .
List of Figures
Figure 1. Topographic and Location Map
Figure 2. Site and Exploration Plan
APPENDIX A
Soil Classification Chart and Key to Test Data
Test Pit Log TP-1
Log of Test Hole TH-1
APPENDIXB
Laboratory Testing Results .................. .
. ................ 2
. ................... 5
.... A-1
.... A-2
.... A-3
..B-1 ... 8-4
March 20, 2015
Tl5023
Encompass Engineering and Surveying
165 NE Juniper St, Suite 201
Issaquah, WA 98027
Attention:
Subject:
Timothy Collins
Geotechnical Engineering Report
Tax Parcel -33457002 l 5
Residential Plat
3616 Lincoln Ave NE
Renton, Washington
Dear Mr, Collins:
PO Box 44840
Tacoma, WA 98448
253-537-9400
253-537-9401 Fax
E3RA, Inc. (E3RA) is pleased to submit this report describing the results of our geotechnical engineering
evaluation of the improvements planned for the residential lot located at 3616 Lincoln Ave NE in Renton,
Washington.
This report has been prepared for the exclusive use of Encompass Engineering and Surveying, and their
consultants, for specific application to this project, in accordance with generally accepted geotechnical
engineering practice.
1.0 SITE AND PROJECT DESCRIPTION
The project site consists of a rectangular shaped residential parcel located directly northeast of the intersection
of Lincoln Ave NE and NE 36th Street in Renton, Washington as shown on the enclosed Topographic and
Location Map (Figure I). It is bounded on the west by Lincoln Ave NE, the south by NE 36th Street, the east
by Lincoln Ct NE, and on the north by a residential parcel, encompassing just over a Y, acre.
Visually, the parcel is easily divided into two distinct areas; the west half and east half. Located centrally
within the west half of the property is the existing single family residence; which is wood-framed, two-stories,
and was originally constructed in 1993. Extending to the residence from Lincoln Ave NE is a concrete
driveway, with areas north of the driveway serving as the front lawn, and areas south of the driveway
containing a gravel surfacing that acts as overflow parking/storage. A small shed building is located directly
south of the residence. The east half of the parcel is what would be considered the backyard area and is
entirely contained within a large wooden fence. The north halfofthe east side of the property contains an
athletic court used apparently for basketball or tennis, with nets being erected on either side of the court. The
south half of the east end of the parcel is predominantly occupied by an open grassy lawn. Areas between the
residence and athletic court and/or lawn area are occupied by gravel walkways and landscaping features.
March 20. 2015 E3RA, Inc.
T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
Preliminary plans involve the short-plat of the parcel, with the property being divided east/west into two
residential lots designated Lot l and Lot 2. Lot 1 will contain the existing single family residence, while Lot 2
will contain what currently consists of the athletic court and back lawn area. It is our assumption that a new
residence will be constructed in Lot 2, and we do not know if the existing residence will be demolished or
retained.
2.0 EXPLORATORY METHODS
We explored surface and subsurface conditions at the project site on March 5, 2015. Our exploration program
comprised the following elements:
A surface reconnaissance of the site;
One Test Pit Exploration (designated TP-1) performed in the southwest comer of the site;
One Test Hole Exploration (designated TH-l) performed in the east end of the site;
Two grain size analyses performed on soil samples collected from our subsurface
explorations; and
A review of published geologic and seismologic maps and literature.
Table I summarizes the approximate functional locations and termination depths of our subsurface
explorations, and Figure 2 depicts their approximate relative locations. The following sections describe the
procedures used for excavation of test pits.
TABLE 1
APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS
Termination
Exploration Functional Location Depth
(feet)
TP-1 Southwest corner of the site 11
TH-1 Southeast corner of the site 6
The specific number and locations of our explorations were selected in relation to the existing site features,
under the constraints of surface access, underground utility conflicts, and budget considerations.
It should be realized that the explorations performed and utilized for this evaluation reveal subsurface
conditions only at discrete locations across the project site and that actual conditions in other areas could vary.
Furthermore, the nature and extent of any such variations would not become evident until additional
explorations are performed or until construction activities have begun. If significant variations are observed
at that time, we may need to modify our conclusions and recommendations contained in this report to reflect
the actual site conditions.
2.1 Test Pit Procedures
Our exploratory test pit was excavated with a rubber-tracked excavator owned and operated by an excavation
contractor under subcontract to E3 RA. An engineering geologist from our firm observed the test pit
excavation and logged the subsurlace conditions.
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T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
The enclosed test pit log indicate the vertical sequence of soils and materials encountered in the test pit, based
on our field classifications. Where a soil contact was observed to be gradational or undulating, our log
indicates the average contact depth. We estimated the relative density and consistency of the in-situ soils by
means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the
approximate depths of any sidewall caving or groundwater seepage observed in the test pit. The soils were
classified visually in general accordance with the system described in Figure A-1, which includes a key to the
exploration log. A summary log of the exploration is included as Figure A-2.
Test Hole Procedures
Our exploratory test hole was excavated with a shovel, post hole digger, iron bar, and 3 inch hand auger by an
engineering geologist from E3RA, who also logged the subsurface conditions.
The enclosed test hole log indicates the vertical sequence of soils and materials encountered in the test hole,
based on our field classifications. Where a soil contact was observed to be gradational or undulating, our log
indicates the average contact depth. We estimated the relative density and consistency of the in-situ soils by
means of the excavation characteristics and the stability of the test pit sidewalls. Samples of soils were
collected. Our log also indicates the approximate depths of the samples collected and any sidewall caving or
groundwater seepage observed. The soils were classified visually in general accordance with the system
described in Figure A-1, which includes a key to the exploration log. A summary log of the exploration is
included as Figure A-3.
3.0 SITE CONDITIONS
The following sections present our observations, measurements, findings, and interpretations regarding,
surface, soil, groundwater, seismic, and liquefaction conditions.
Surface Conditions
As previously described, development plans involve the sub-plat of the subject property into two residential
lots designated Lot 1 and Lot 2. Lot 1 or the westernmost lot is predominately level, with only a slight slope
proponent near the western and northern margins of the parcel, towards the west and north, respectively. Lot 2
is also predominately level, containing a slight slope element towards its northern boundary, representing an
elevation change of 3 to 5 feet. The grassy lawn area in the southeast comer of the site was constructed
approximately 2 to 3 feet higher than that of adjacent grades, with concrete steps being constructed along its
northern extent to provide access to the area.
Vegetation on site consists primarily of ornamental lawns, trees and shrubs. Larger growths of trees/shrubs
line the western, southern and eastern margins of the site.
No hydrologic features were observed on site, such as seeps, springs, ponds and streams.
Soil Conditions
Our subsurface explorations encountered relatively consistent soil conditions across the project site. In the
vicinity of test pit exploration TP-1, performed in the southwest comer of the site, we observed that a surface
mantle of 12 inches of pea gravel covers this portion of the project area. The original topsoil horizon was
encountered immediately beneath the gravel surfacing, and is underlain by native, sandy soils. From a depth of
1 Y, to 8Y, feet below existing grade we encountered fine, silty sand in a medium dense in-situ condition, with
the upper 3 Y, feet of these deposits displaying mottling. From 8Y, to 11 feet below grade, the termination depth
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March 20, 2015
T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
for this exploration, soils transitioned to fine sand with silt. Sieve analyses performed on each of these distinct
soil groups indicate that the upper deposits contain a fines (percent silt/clay) content in excess of30 percent,
while the deeper deposits contain a fines content of less than 8 percent.
Test hole exploration TH-1 encountered similar sandy soils with depth, but a thicker, surficial topsoil horizon.
The attached exploration logs provide a detailed description of the soil strata encountered in our subsurface
explorations.
Groundwater Conditions
At the time of our site reconnaissance and subsurface explorations, we did not encounter groundwater in any of
our explorations, which extended to a nominal depth of 11 feet below existing grades. Given the fact that our
subsurface explorations were performed during what is generally considered the wet season (October 1st
through April 301h), we do not anticipate that groundwater levels will rise higher than that which we observed,
nor do we anticipate that groundwater will adversely affect proposed earthwork activities. Groundwater levels
will fluctuate with localized precipitation and geology.
3.4 Seismic Conditions
Based on our analysis of subsurface exploration logs and our review of published geologic maps, we interpret
the onsite soil conditions to generally correspond with site class D, as defined by Table 20.3-1 inASCE 7, per
the 2012 International Building Code (!BC).
Using 2012 IBC information on the USGS Design Summary Report website, Risk Category !/!I/III seismic
parameters for the site are as follows:
S, = 1.437g SMs = 1.437g Sos= 0.958g
S1 = 0.545g SM\= 0.818g SDI= 0.545g
Using the 2012 IBC information, MCEs Response Spectrum Graph on the USGS Design Summary Report
website, Risk Category I/II/III, S,at a period of0.2 seconds is 1.44g and S,at a period of 1.0 seconds is 0.82g.
The Design Response Spectrum Graph from the same website, using the same IBC information and Risk
Category, S,at a period of0.2 seconds is 0.96g and S,at a period of 1.0 seconds is 0.55g.
3.5 Liquefaction Potential
Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by
shear strains, as could result from an earthquake. Research has shown that saturated, loose sands with a fines
(silt and clay) content less than about 20 percent are most susceptible to liquefaction. Our onsite subsurface
explorations did not reveal saturated ( or potentially saturated), loose, silty sand layers or lenses.
3.6 Infiltration Conditions and Infiltration Rate
At the time of report preparation, it is not known whether onsite infiltration will be incorporated into the
project stormwater management plan, nor, ifit is the size, location, or dimensions of new facilities. lf onsite
infiltration is implemented as part of the new development, we offer the following recommendations.
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T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
Based on our field observations and grain size analyses (presented in Table 2, below), two distinct soil stratum
are available on site as medium for possible infiltration. The upper native deposits consist of fine silty sand,
with fines content in excess of30 percent. At a depth of 8Vz feet below existing grade, more readily permeable
sandy soils are encountered with a fines content less than 8 percent.
The results of our soil grain size analyses are presented below, and the attached Soil Gradation Graphs
(Appendix B) display the grain-size distribution of the samples tested.
TABLE2
LABORATORY TEST RESULTS FOR NON-ORGANIC ONSITE SOILS
Soil Sample, Depth % Coarse % Fine % Coarse %Medium %Fine % Fines D10
Gravel Gravel Sand Sand Sand
TP-1, S-1, 3 feet 0 6.4 0.4 2.5 60.3 30.4 -
TP-1, S-3, 9 feet 0 0 0.4 1.1 90.9 7.6 0.08
Preliminary Recommended Infiltration Rate
Specific locations and geometry of infiltration facilities for the project site had not been determined at the time
this report was prepared. Therefore, we have provided a generalized infiltration rate for use in preliminary
design of any future infiltration facilities planned in the site area. If onsite infiltration is implemented.,
infiltration testing is recommended in the vicinity of new facilities at or near their proposed invert elevations.
We determined a preliminary infiltration rate for the project site by comparing the results of our sieve analyses
from test pit exploration TP-1 with Table 3.7, in Volume III of the 2005 DOE Stormwater Management
Manual for Western Washington, located on page 3-76. Using the U.S.D.A. Textural Triangle, the upper soil
deposits are classified as sandy loam and the deeper deposits are classified as sand with corresponding
recommended long-term infiltration rates of0.25 in/hr and 2 in/hr respectively.
4.0 CONCLUSIONS AND RECOMMENDATIONS
Plans call for the sub-plat of an existing residential parcel in Renton, Washington and the construction of a new
single family residence with associated paved surfaces for the driveway and parking. We offer these general
conclusions and recommendations:
Erosion Hazards: Most of the site presents a moderate erosion hazard. Standard erosion
control measures, such as silt fences or mulch berms, temporary protection of bare soils with
plastic, mulch, or other cover, and permanent re-vegetation of bare soils, is recommended.
Erosion control recommendations are made in the Site Preparation section in Section 4.1.
Foundation Options: We recommend conventional spread footings that bear on medium
dense or denser native soils, which are generally found within a few feet of the surface of the
site. Recommendations for spread footings are provided in Section 4.2.
Floor Options: We recommend concrete slab-on-grade floors for the structure.
Recommendations for slab-on-grade floors are included in Section 4.3.
Drainage Considerations: We recommend that perimeter drains be placed around foundation
footings. Recommendations for drainage systems are included in Section 4.4.
Pavement Sections: Native, in-situ soil conditions are amenable to the use of soil-supported
pavements. We recommend a conventional pavement section comprised of an asphalt
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T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
concrete pavement over a crushed rock base course over a properly prepared ( compacted)
subgrade or a granular subbase, depending on subgrade conditions during pavement subgrade
preparation.
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump
truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this
proof-rolling operation should be overexcavated to a depth of 12 inches and replaced with a
suitable structural fill material.
Infiltration Recommendations: If infiltration of site produced stonmwater becomes
incorporated into the new development, we recommend using a preliminary infiltration rate of
0.25 in/hr for the upper, siltier soils, and a rate of 2 in/hr for the lower (those encountered
below 8'1, feet bgs ), sandier soils. If infiltration is implemented, we recommend infiltration
testing in the vicinity ofnew facilities.
The following sections present our specific geotechnical conclusions and recommendations concerning site
preparation, spread footings, slab-on-grade floors, drainage, subgrade walls, temporary shoring, and structural
fill. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard
Plans cited herein refer to WSDOT publications M4 I -10, Standard Specifications for Road, Bridge, and
Municipal Construction, and M2 I-O I, Standard Plans for Road, Bridge, and Municipal Construction,
respectively.
4.1 Site Preparation
Preparation of the project site should involve erosion control, temporary drainage, clearing, stripping, cutting,
filling, excavations, and subgrade compaction.
Erosion Control: Before new construction begins, an appropriate erosion control system should be installed.
This system should collect and filter all surface run off from the construction areas through silt fencing. We
anticipate a system ofbenms and drainage ditches around construction areas will provide an adequate collection
system. Silt fencing fabric should meet the requirements ofWSDOT Standard Specification 9-33.2 Table 3.
In addition, silt fencing should embed a minimum of 6 inches below existing grade. An erosion control system
requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has
shifted above ground surface should be replaced or repaired as soon as they are identified.
As an alternative, mulch-type berms, such as described in the latest Washington Department of Ecology Storm
Water Manual, can be deployed immediately down slope of construction areas until vegetation has been
re-established there.
Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or
near-surface water within the construction zones before stripping begins. Because the selection of an
appropriate drainage system will depend on the water quantity, season, weather conditions, construction
sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the
time of construction. Based on our current understanding of the construction plans, surface and subsurface
conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept
surface water runoff.
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T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
Clearing and Stripping: After surface and near-surface water sources have been controlled, the construction
areas should be cleared and stripped of all sod, topsoil, and root-rich soil. Based on our subsurface
explorations, the organic laden horizon can be upwards of24 inches thick within the project area.
Site Excavations: Based on our explorations, we expect that site excavations will encounter moderately dense
sandy soils which can readily excavated using standard equipment.
Dewatering: Our explorations did not encounter groundwater within their termination depths, nor do we
expect that groundwater will be present in the planned excavations. However, if groundwater is encountered,
we anticipate that an internal system of ditches, sump holes, and pumps will be adequate to temporarily
dewater excavations.
Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be
adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper
than 1 V. H:I V, and should conform to Washington Industrial Safety and Health Act (WISHA) regulations.
Subgrade Compaction: Exposed subgrades for footings, slabs, and floors should be compacted to a firm,
unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils
observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In
contrast, any organic, soft, or pumping soils observed within a subgrade should be overexcavated and replaced
with a suitable structural fill material. Surface compaction of all footing and slab subgrades is recommended,
although surface compaction could become problematic during wet weather conditions or when in situ site
soils become wet.
Site Filling: Our conclusions regarding the reuse of onsite soils and our comments regarding wet-weather
filling are presented subsequently. Regardless of soil type, all fill should be placed and compacted according
to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill
soil should be compacted to a uniform density of at least 95 percent (based on ASTM D-1557).
Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural
fill:
Surficial Organic Soils: The topsoil and root-rich soil that overlies the site is not suitable for
use as structural fill under any circumstances, due to high organic content.
Fine Silty Sand and Fine Sand with Silt: Our subsurface explorations reveal that native soils
on site consist of fine silty sand and fine sand with silt. Each soil type contains a significant
fines proponent (percent si!Vclay), and will be moisture sensitive. Reusing this material type
as structural fill will become increasing difficult in wet weather conditions.
Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term
raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H: IV.
For all soil types, the use of flatter slopes (such as 2Y,H: IV) would further reduce long-term erosion and
facilitate revegetation.
Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the top edge of
all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as
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March 20, 2015 E3RA, Inc.
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soon as feasible, to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could
be annored with quarry spalls or a geosynthetic erosion mat.
Spread Footings
In our opinion, conventional spread footings will provide adequate support for the proposed structure if the
subgrades are properly prepared.
Footing Depths and Widths: For frost and erosion protection, the bases of all exterior footings should bear at
least 18 inches below adjacent outside grades, whereas the bases of interior footings need bear only 12 inches
below the surrounding slab surface level. To reduce post-construction settlements, continuous (wall) and
isolated (column) footings should be at least 18 and 24 inches wide, respectively.
Bearing Subgrades: Footings should bear on medium dense or denser, undisturbed native soils or on properly
compacted structural fill which bears on undisturbed medium dense or very dense native soils. In general,
before footing concrete is placed, any localized zones of loose soils exposed across the footing subgrades
should be compacted to a firm, unyielding condition, and any localized zones of soft, organic, or debris-laden
soils should be overexcavated and replaced with suitable structural fill. We recommend vigorous surface
compaction of footing subgrades to a medium dense or denser condition.
Sub grade Observation: All footing subgrades should consist of firm, unyielding, native soils or structural fill
materials compacted to a density of at least 95 percent (based on ASTM:D-1557). Footings should never be
cast atop loose, soft, or frozen soil, slough, debris, existing uncontrolled fill, or surfaces covered by standing
water.
Bearing Pressures: In our opinion, for static loading, footings that bear on properly prepared subgrades can be
designed for a maximum allowable soil bearing pressure of2,000 pounds per square foot (psf). A one-third
increase in allowable soil bearing capacity may be used for short-term loads created by seismic or wind related
activities.
Footing Settlements: Assuming that structural fill soils are compacted to a medium dense or denser state, we
estimate that total post-construction settlements of properly designed footings bearing on properly prepared
subgrades will not exceed I inch. Differential settlements for comparably loaded elements may approach
one-half of the actual total settlement over horizontal distances of approximately 50 feet.
Footing Backfill: To provide erosion protection and lateral load resistance, we recommend that all footing
excavations be backfilled on both sides of the footings and stemwalls after the concrete has cured. Either
imported structural fill or non-organic onsite soils can be used for this purpose, contingent on suitable moisture
content at the time of placement. Regardless of soil type, all footing backfill soil should be compacted to a
density of at least 90 percent (based on ASTM:D-1557).
Lateral Resistance: Footings that have been properly backfilled as recommended above will resist lateral
movements by means of passive earth pressure and base friction. We recommend using an allowable passive
earth pressure of275 pcf and an allowable base friction coefficient of0.35.
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Slab-On-Grade Floors
In our opinion, soil-supported slab-on-grade floors can be used in the proposed structure if the sub grades are
properly prepared. We offer the following comments and recommendations concerning slab-on-grade floors.
Floor Subbase: Structural fill subbases do not appear to be needed under soil-supported slab-on-grade floors
at the site. However, the final decision regarding the need for subbases should be based on actual subgrade
conditions observed at the time of construction. If a subbase is needed, all subbase fill should be compacted
to a density ofat least 95 percent (based on ASTM:D-1557). All subgrades should be vigorously surface
compacted to a medium dense or denser condition before slab construction begins.
Capillary Break and Vapor Barrier: To retard the upward wicking of groundwater beneath the floor slab, we
recommend that a capillary break be placed over the subgrade. Ideally, this capillary break would consist of a
6-inch-thick layer of pea gravel or other clean, uniform, well-rounded gravel, such as "Gravel Backfill for
Drains" per WSDOT Standard Specification 9-03.12(4), but clean angular gravel can be used if it adequately
prevents capillary wicking. In addition, a layer of plastic sheeting (such as Crosstuff, Visqueen, or Moistop)
should be placed over the capillary break to serve as a vapor barrier. During subsequent casting of the concrete
slab, the contractor should exercise care to avoid puncturing this vapor barrier.
Vertical Deflections: Due to elastic compression of sub grades, soil-supported slab-on-grade floors can deflect
downwards when vertical loads are applied. In our opinion, a subgrade reaction modulus of250 pounds per
cubic inch can be used to estimate such deflections.
4.4 Drainage Systems
In our opinion, the planned structure should be provided with permanent drainage systems to reduce the risk of
future moisture problems. We offer the following recommendations and comments for drainage design and
construction purposes.
Perimeter Drains: We recommend that structures be encircled with a perimeter drain system to collect seepage
water. This drain should consist of a 6-inch-diameter perforated pipe within an envelope of pea gravel or
washed rock, extending at least 6 inches on all sides of the pipe, and the gravel envelope should be wrapped
with filter fabric to reduce the migration of fines from the surrounding soils. Ideally, the drain invert would be
installed no more than 8 inches above the base of the perimeter footings.
Subfloor Drains: Based on the groundwater conditions observed in our site explorations, we do not infer a
need for subtloor drains.
Discharge Considerations: ff possible, all perimeter drains should discharge to a storm sewer system or other
suitable location by gravity flow. Check valves should be installed along any drainpipes that discharge to a
sewer system, to prevent sewage backflow into the drain system. ff gravity flow is not feasible a pump system
is recommended to discharge any water that enters the drainage system.
Runoff Water: Roof-runoff and surface-runoff water should not discharge into the perimeter drain system.
Instead, these sources should discharge into separate tightline pipes and be routed away from the building to a
storm drain or other appropriate location.
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Grading and Capping: Final site grades should slope downward away from the buildings so that runoff water
will flow by gravity to suitable collection points, rather than ponding near the building. fdeally, the area
surrounding the building would be capped with concrete, asphalt, or low-permeability (silty) soils to minimize
or preclude surface-water infiltration.
Asphalt Pavement
We offer the following comments and recommendations for asphalt pavement design and construction.
Subgrade Preparation: Structural fill subbases do not appear to be needed under pavements at the site.
However, the final decision regarding the need for subbases should be based on actual subgrade conditions
observed at the time of construction. If a subbase is needed, all sub base fill should be compacted to a density
of at least 95 percent (based on ASTM:D-1557).
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy
compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be
over excavated to a minimum depth of 12 inches and replaced with a suitable structural fill material. All
structural fill should be compacted according to our recommendations given in the structural fill section.
Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 95 percent
(based on ASTM D-1557), and all soils below 2 feet should be compacted to at least 90 percent.
Pavement Materials: For the base course, we recommend using imported crushed rock, such as "Crushed
Surfacing Top Course" per WSDOT Standard Specification 9-03.9(3). If a subbase course is needed, we
recommend using imported, clean, well-graded sand and gravel such as "Ballast" or "Gravel Borrow" per
WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively.
Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete
pavement over a crushed rock base course. We recommend using the following conventional pavement
sections:
Pavement Course
Asphalt Concrete Pavement
Crushed Rock Base
Granular Fill Subbase (if needed)
Parking Areas
2inches
4inches
6 inches
Minimum Thickness
Access Roads and Areas Subjectto
Truck Traffic
3inches
6 inches
12 inches
Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent
of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted
to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an E3RA representative be
retained to observe the compaction of each course before any overlying layer is placed. For the subbase and
pavement course, compaction is best observed by means of frequent density testing. For the base course,
methodology observations and hand-probing are more appropriate than density testing.
Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described pavement
sections present our minimum recommendations for an average level of performance during a 20-year design
life; therefore, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life
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March 20, 2015
T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
typically assumes that an overlay will be placed after about IO years. Thicker asphalt and/or thicker base and
subbase courses would offer better long-term performance, but would cost more initially; thinner courses
would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be
considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and
higher maintenance costs.
Structural Fill
The term "structural fill" refers to any material placed under foundations, retaining walls, slab-on-grade floors,
sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning
structural fill are presented in the following paragraphs.
Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock,
well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit-run"), and miscellaneous
mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing
the parent materials, are also potentially useful as structural fill in certain applications. Soils used for structural
fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches in
diameter.
Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be placed in
horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a
mechanical compactor.
Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that
structural fill used for various onsite applications be compacted to the following minimum densities:
Fill Application
Footing subgrade and bearing pad
Foundation backfill
Slab-on-grade floor subgrade and subbase
Asphalt pavement base and subbase
Asphalt pavement subgrade (upper 2 feet)
Asphalt pavement subgrade (below 2 feet)
Minimum Compaction
95 percent
90 percent
95 percent
95 percent
95 percent
90 percent
Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill should
be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this
report. The condition of all subgrades should be observed by geotechnical personnel before filling or
construction begins. Also, fill soil compaction should be verified by means ofin-place density tests performed
during fill placement so that adequacy of soil compaction efforts may be evaluated as earthwork progresses.
Soil Moisture Considerations: 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.
For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that
have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve.
11
March 20, 2015 E3RA, Inc
T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineenng Report
5.0 RECOMMENDED ADDITIONAL SERVICES
Because the future performance and integrity of the structural elements will depend largely on proper site
preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced
geotechnical personnel should be considered an integral part of the construction process. Consequently, we
recommend that E3RA be retained to provide the following post-report services:
Provide design plans for temporary basement shoring walls, if needed;
Review all construction plans and specifications to verify that our design criteria presented in
this report have been properly integrated into the design;
Prepare a letter summarizing all review comments (if required);
Check all completed subgrades for footings and slab-on-grade floors before concrete is
poured, in order to verify their bearing capacity; and
Prepare a post-construction letter summarizing all field observations, inspections, and test
results (if required).
6.0 CLOSURE
The conclusions and recolllffiendations presented in this report are based, in part, on the explorations that we
observed for this study; therefore, if variations in the subgrade conditions are observed at a later time, we may
need to modify this report to reflect those changes. Also, because the future performance and integrity of the
project elements depend largely on proper initial site preparation, drainage, and construction procedures.
monitoring and testing by experienced geotechnical personnel should be considered an integral part of the
construction process. E3RA is available to provide geotechnical monitoring of soils throughout construction.
We appreciate the opportunity to be of service on this project. If you have any questions regarding this report
or any aspects of the project, please feel free to contact our office.
Sincerely,
E3RA, Inc.
Zach L. Logan
Staff Geologist
ZLL:JEB:jb
James E. Brigham, P.E.
Principal Engineer
T ACOV2015 JOB FILES1 T 15023 Encompass · Un coin A 11e Geotech\ T! .5023 Encompass Engineering . Lincoln Ave Geotech Report.doc
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TEST PIT LOCATIONS N
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TEST HOLE LOCATIONS ·r TH-1
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E3RA Inc.
PO Box 44840
Tacoma, WA 98448
253-537-9400
253-537-9401 fax
www.e3ra.com
PROJECT: 3616 Lincoln Ave NE
Renton, Washington
SHEET TITLE: Site and Exploration Plan
DESIGNER: CRL JOB NO. T15023
DRAWN BY: CRL SCALE: As Shown
CHECKED BY: JEB FIGURE:2
DATE: Mar. 11, 2015 FILE: T15023.dwg
APPENDIX A
SOIL CLASSIFICATION CHART AND
KEY TO TEST DATA
LOGS OF TEST PITS
~
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6
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MAJOR DIVISIONS
CLEAN GRAVELS
GRAVELS WITH LITTLE OR
NO FINES
MORE THAN HALF
"' . COARSE FRACTION
::::! _[i IS LARGER THAN 0 0 GRAVELS WITH "'0 N0.4SIEVE cg OVER 15% FINES
"' " :;; A
cl! 'a
(!) I
CLEAN SANDS W C
"';,, SANDS WITH LITTLE "' -c3 ~ OR NO FINES u"' MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN
SANDS WITH NO. 4 SIEVE
OVER 15% FINES
TYPICAL NAMES
\1\/Ell GRADED GRAVELS, GRAVEL-SANO MIXTURES
POORLY GRADED GRAVELS. GRAVEL.sAND MIXTURES
GM ~ Ir o SIL lY GRAVELS, POORLY GRADED GRAVEL-sAND-SJLT
MIXTURES
GC
swf ..
SP
CLAYEY GRAVELS. POORLY GRADED GRAVEL-SAND-CLAY
MIXTURES
WELL GRADED SANDS. GRAVELLY SANDS
POORLY GRADED SANDS. GRAVELLY SANDS
-:· .. •
SM ;. :·. SILTY SANDS. POOORLYGRADEDSAND-SILTMIXTURES
SC ri,/ i CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES
ML
INORGANIC SIL TS AND VERY FINE SANDS. ROCK FLOUR.
SIL TY OR CLAYEY FINE SANDS. OR CLAYEY SILTS WITH
• SILTS AND CLAYS Ell f-f--1N_O_R_GA_N_1_c_c_LA_Y_s_o_F_L_o_w_T_O_M_rn_1u_M_P_LAS_T_1c-1TY_. __ -----i u, .~ GRAVELLY CLAYS, S,I\NDYClAYS, SILTY CLAYS, ~ 0 LIQUID LIMIT LESS THAN 50 LEAN CLAYS ag
~ ~ QL 1------....: ORGANICClAYSANDORGANICSILTYCLAYSOFLOW
SLIGHT PLASTICITY
w v --PLASTICITY
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DS
PM
pp
SIL TS AND CLAYS
LIQUID LIMIT GREATER THAN 50
HIGHLY ORGANIC SOILS
Modified California
Split Spoon
Pushed Shelby Tube
Auger Cuttings
Grab Sample
Sample Attempt with No Recovery
Chemical Analysis
Consolidation
Compaction
Direct Shear
Permeability
Pocket Penetrometer
MH
CH
OH
~~
INORGANIC SIL TS, MICACEOUS OR DIATOMACIOUS FINE
SANDY OR SIL TY SOILS, ELASTIC SIL TS
INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SIL TS
Pt ~ ,11, PEAT ANO OTHER HIGHLY ORGANIC SOILS
RV R-Value
SA Sieve Analysis
SW Swell Test
TC Cyclic T riaxial
TX Unconsolidated Undrained Triaxial
N Toivane Shear
UC Unconfined Compression
(1.2) (Shear Strength, ksf)
WA Wash Analysis
(20) (with % Passing No. 200 Sieve)
'Sl. Water Level at Time of Drilling
.Y Water Level after Drilling(with date measured)
SOIL CLASSIFICATION CHART AND KEY TO TEST DATA
Figure A-1
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MAJOR DIVISIONS
CLEAN GRAVELS
GRAVELS WITH LITTLE OR
NO FINES
MORE THAN HALF
"' . COARSE FRACTION
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"'0 NO. 4SIEVE
Q 0 OVER 15% FINES w ~
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CLEAN SANDS W C
"'1 SANDS WITH LITTLE "' -"' ~ OR NO FINES 0 o
u " MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN SANDS WITH N0.4 SIEVE
OVER 15% FINES
TYPICAL NAMES
is·.-:11
GW :·•~ WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES .... ,
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GP ·,:[)~ POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES lb l)
GM ~ i,.., d SIL TY GRAVELS, POORLY GRADED GRAVEL-sANO-Sll T
MIXTURES
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SC it.
CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY
MIXTURES
WELL GRADED SANDS, GRAVELLY SANDS
POORLY GRADED SANDS. GRAVELLY SANDS
SIL TY SANDS, POOORL Y GRADED SAND-SILT MIXTURES
CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES
INORGANIC SILTS ANO VERY FINE SANDS, ROCK FLOUR,
SIL TY OR CLAYEY FINE SANDS, OR CLAYEY SIL TS \MTI,
SLIGHT PLASTICITY
• SIL TS AND CLAYS f-'-1N~O~R-'-GAN-1c_c_LA_Y_s_o_F_Lo_w_T_O_M_E_D_1u_M_P_LAS_T_1c-1TY-. -----,
~ -~ L GRAVELLY CLAYS, SANDYCLAYS,SILTYCLAYS, -•• LIQUID LIMIT LESS THAN 50 LEAN CLAYS i5 0 ~ ~ QL ~ -ORGANIC CLAYS AND ORGANIC SIL TY CLAYS OF LOW
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SILTS AND CLAYS
LIQUID LIMIT GREATER THAN 50
HIGHLY ORGANIC SOILS
Modified California
Splrt Spoon
Pushed Shelby Tube
Auger Cuttings
Grab Sample
Sample Attempt with No Recovery
Chemical Analysis
Consolidation
Compaction
Direct Shear
Penneability
Pocket Penetrometer
MH
CH
OH
INORGANIC SIL TS, MICACEOUS OR DIATOMACIOUS FINE
SANDY OR SIL TY SOILS, ELASTIC SIL TS
INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SIL TS
Pt i!t. -11, PEATANDOTHERHIGHLYORGANICSOILS
RV R-Value
SA Sieve Analysis
SW Swell Test
TC Cyclic Triaxial
TX Unconsolidated Undrained T Jiaxial
TV Torvane Shear
UC Unconfined Compression
(1.2) (Shear Strength, ksf)
WA Wash Analysis
(20) (with % Passing No. 200 Sieve)
'l-Water Level at Time of Drilling
.J: Water Level after Drilling{with date measured)
SOIL CLASSIFICATION CHART AND KEY TO TEST DATA
FigureA-1
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E3RA, Inc. TEST PIT NUMBER TP-1
P.O. Box44840 PAGE 1 OF 1 IE RA, Inc. i Tacoma. WA 98448 Figure A-2
i i Telephone: 253-537-9400
Fax: 253-537-9401
CLIENT EncomQaSS Engineering & Surveving PROJECT NAME 3616 Lincdn Ave NE -
PROJECT NUMBER T15023 PROJECT LOCATION Renton, Washing!pn
DATE STARTED 3/5115 COMPLETED 315115 GROUND ELEVATION TEST PIT SIZE -------·------
EXCAVATION CONTRACTOR DSE GROUND WATER LEVELS: ---·-···---
EXCAVATION METHOD Steel Tracked Excavator AT TIME OF EXCAVATION ----
LOGGED BY ZLL CHECKED BY JEB AT END OF EXCAVATION -
NOTES AFTER EXCAVATION
w a.
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a."' ..., :. ui a. 0 MATERIAL DESCRIPTION w-a?..., 0 a.:::, :::i :. z "' <(
(fJ
0.0
(GP) Gray gravel with sand and trace silt (loose, moist) (Fill)
GP
1.0
SM ! (SM) Dark brown silty sand with some gravel, copious organics, and small root complexes (loose, moist) (Topsoil Horizon)
1.5 -" ~
(SM) Tan mottled fine silty sand (medium dense, moist)
-"
1~--
r GB
S-1 SM
r
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(SM) Tan fine silty sand (medium dense, moist)
-
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8.5 -
! (SP-SM) Tan fine sand with silt (medium dense, moist)
GB 11 S-3 ,,
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---1Q&. SM !
I
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11.0
No caving observed
No groundwater seepage observed
The depths on the test pit logs are based on an average of measurements across the test pit and should be considered
accurate to 0.5 foot.
Bottom of test pit at 11.0 feet.
! E3RA, Inc. I
E3RA Inc. BORING NUMBER TH-1
P.O. Bax 44840 PAGE 1 OF 1
T acorn a. WA 98448 Figure A-3 l__ _j Telephone: 253-537-9400
Fax: 253-537-9401
CLIENT Encomi:1ass Engineering & Survey'ing PROJECT NAME 3616 Lincoln Ave NE
PROJECT NUMBER _I1502~ _ -----------------PROJECT LOCATION RentqriJ__Wash_inoton
DATE ST ART ED 315115 COMPLETED 315115 GROUND ELEVATION HOLE SIZE
DRILLING CONTRACTOR DSE GROUND WATER LEVELS:
DRILLING METHOD Steel Tracked Excavator AT TIME OF DRILLING ------·--
LOGGED BY ZLL CHECKED BY JEB AT END OF DRILLING -
NOTES AFTER DRILLING -
UJ
0. u I ~ffi ui r CJ t= UJ "' u a. 0 MATERIAL DESCRIPTION w-~:, ui c2 ~ Cl 0.:::, :::i :, z CJ "' "' 0
" l lL1..r\ Landscaping bark
------·---------r -SM (SM) Dark brawn silty sand with copious organics (loose, moist) (Topsoil Horizon)
2.0 Large root complexes encountered at 1 foot ~ ----------__ .,-
(SM) Tan fine silty sand (medium dense, moist)
f-.
GB i
S-1 SM
__L
6.0
No caving observed
No groundwater seepage observed
The depths on the test pit logs are based on an average of measurements across the test pit and should be CCN1sidered
accurate to 0.5 foot.
Bottom of borehole at 6.0 feet.
APPENDIX B
LABORATORY TESTING RES UL TS
Particle Size Analysis Summary Data
Job Name: 3616 Lincoln Ave NE, Renton Geotech
Job Number: T15023
Tested By: CF
Date: 3/6115
Boring #: TP-1
Sample#: 1
Depth: 3' bgs
JMoisture Content(%) I 24.0°/,1
Sieve Size Percent Size Fraction Percent By
Passing(%) Weight
3.0 in. (75 0) 100.0 Coarse Gravel
1.5 in. 37.5) 100.0 Fine Gravel 6.4
3/4 in. 19.0\ 100.0
318 in. 9.5-mm\ 100.0 Coarse Sand 0.4
No. 4 4.75-mm\ 93.6 Medium Sand 2.5
No. 10 (2.00-mm) 93.2 Fine Sand 60.3
No. 20 i.850-mm\ 92.2
No. 40 (.425-mm) 90.7 Fines 30.4
No. 60 i.250-mm\ 86.6 Total 100.0
No. 100 i.150-mm\ 67.5
No. 200 i.075-mm\ 30.4
LL
Pl
D10
D30
D60 0.13
Cc
Cu
ASTM Classification
r Group Name Light-brown silty sand
Symbol (SM) (med. dense, moist)
E3RA Figure 8-1
Soil Classification Data Sheet
Sample Distribution
U.S. Standard Sieve Sizes
, .. 1.5" 3/4" 3/8" 4 10
-+-Sample Distribution
20 40 60 100 200
I I I I I I I I I I I
100 ' I
··-----
I
~~
90 --
~ '
I i
80 '
-
70 --\ ' \ i
I
' I
"' C 60 ' "iii \ "' : ..
' D. 50 T --i C .. i I I:! 40 -
I .. I ' D. I I
-30
'
--
I I I I I
I I I 20 -I --
I I
!
10
I I
'
' I
i o I I i I
1000 100 10 1 0.1 0.01 0.001
Particle Size (mm)
E3RA Sample Distribution Job Name: 3616 Lincoln Ave NE, Renton Ge Sample#: 1
Job Number: T15023 Date: 3/6/15
Figure: B-2 Tested Bv: CF Deoth: 3' bas
EXPioration #: TP-1
• I I •
Particle Size Analysis Summary Data
Job Name: 3616 Lincoln Ave NE, Renton Geotech
Job Number: T15023
Tested By: CF
Date: 3/6/15
Boring #: TP-1
Sample#: 3
Depth: 9' bgs
I Moisture Content{%) I 23.6%1
Sieve Size Percent Size Fraction Percent By
Passing(%) Weight
3.0 in. 75.0) 100.0 Coarse Gravel
1.5 in. 37.5) 100.0 Fine Gravel
3/4 in. 19.0) 100.0
3/8 in. 9.5-mm) 100.0 Coarse Sand 0.4
No. 41 4.75-mm) 100.0 Medium Sand 1.1
No. 10 (2.00-mm) 99.6 Fine Sand 90.9
No. 20 1.850-mml 99.2
No. 40 (.425-mm) 98.5 Fines 7.6
No. 60 /.250-mm) 85.0 Total 100.0
No. 100 /.150-mml 41.2
No. 200 (.075-mml 7.6
LL
Pl
D10 0.08
D30 0.12
060 0.19
Cc 0.96
Cu 2.37
ASTM aassification
r Group Name Light-brown poorly graded sand with silt
Symbol (SP-SM) (med. dense, moist)
E3RA Figure B-3
Soil Classification Data Sheet
Sample Distribution
U.S. Standard Sieve Sizes
3" 1.5" 3/4" 3/8" 4 10
-+-Sample Distribution
20 40 60 100 200
I I I I I I I I I I I
100 -
/ r
I ~l '
90
\
---
I I i ! ' 80 i ' ---
\ i
' I
70
I
'
I
Cl)
60 C
"iii I\ "' ..
'
Q. 50 ~ I \
~ -I ·. C
Cl) I !:! 40 \ Cl)
' Q.
' 30 ' I ~ ~-
\
---
i i !
20 ----
I
I I
10 . r
0 j I i I -
1000 100 10 1 0.1 0.01 0 001
Particle Size (mm)
E3RA Sample Distribution Job Name: 3616 Lincoln Ave NE, Renton Ge, Samole#: 3
Job Number: T15023 Date: 316115
Figure: 8-4 Tested Bv: CF Deoth: 9' bas
Exe lo ration #: TP-1
•
Encompass f\
ENGINEERING & SUtVEYING ;,;_,,,,,,;
Preliminary Technical Information Report
for
Lincoln Short Plat
3616 Lincoln Ave NE
Renton, WA 98056
Jan 22, 2015
Encompass Engineering Job No. 14694
Prepared For
Highland Real Estate LLC.
4865 Lakehurst Lane SE
Bellevue, WA 98006
Western Washington Division Eastern Washington Division
165 NE Juniper St., Ste 201, Issaquah, WA 98027 108 East 2"• Street, Cle Elum, WA 98922
Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419
www.EncompassES.net
SECTION I:
SECTION II:
SECTION III:
SECTION IV:
SECTIONV:
SECTION VI:
SECTION VII:
SECTION VIII:
SECTION IX:
SECTIONX:
TABLE OF CONTENTS
PROJECT OVERVIEW
CONDITIONS AND REQUIREMENTS SUMMARY
OFF-SITE ANALYSIS
FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS
AND DESIGN
CONVEYANCE SYSTEM ANALYSIS AND DESIGN
SPECIAL REPORTS AND STUDIES
OTHER PERMITS-NA
ESC ANALYSIS AND DESIGN
BOND QUANTITIES, FACILITY SUMMARIES, AND
DECLARATION OF COVENANT-NIA
OPERATIONS AND MAINTENANCE MANUAL-NIA
SECTION 1
PROJECT OVERVIEW
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Site Address:
King County Tax Parcel:
Project Overview
3616 Lincoln Ave NE, Renton WA, 98056
334570-0215
This project involves development of a 22,587 SF parcel into two single-family residential lots.
The existing parcel has an existing house, a sport court, a shed and the remaining area is covered
with several mature trees with lawn. The site generally slopes down to northwest at
approximately 5%.
Per the SCS Soil maps, the site is underlain with Alderwood, gravelly sandy loam, AgC.
-See attached geotechnical report.
Downstream Drainage
The project site drains to northwest in form of sheet flow. Level 1 Downstream Analysis was
conducted on Jan 07, 2015, and this information is presented in Section 3 of this TIR.
Proposed Drainage Controls
This project is a single family residential subdivision. Based on the analysis of the existing and
future propose improvements, the total impervious area for this project exceeds 2,000 square
feet, but it does not exceed a total of 10,000 square feet of impervious surfaces, and therefore it
is subject to Small Project Drainage Review. Basic Bl\1Ps will provide the required flow control.
Refer to Section 4 of this TIR for additional information regarding the Flow Control and Water
Quality BMPs.
King County Department of Development and Environmental Services
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER
Project Owner Highland Real Estate LLC
Address 4865 Lakehurst Lane SE
Bellevue, WA 98006
Phone 206-226-5354
Project Engineer Tom Redding
Company Encompass Engineering
Address/Phone 425-392-0250
Part 3 TYPE OF PERMIT
APPLICATION
X Subdivision
D Short Subdivision
D Grading
D Commercial
D Other ________ _
Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Name Lincoln Short Plat
Location
Township _24 ____ _
Range 05. ____ _
...... NE ....... Section ___ 32. ___ _
SITE ADDRESS: 3616 Lincoln Ave NE
Renton, WA 98056
Part 4 OTHER REVIEWS AND PERMITS
D DFW HPA D Shoreline Management
D COE 404 D Rockery
D DOE Dam Safety D Structural Vaults
D FEMA Floodplain D Other
0 COE Wetlands
Part 5 SITE COMMUNITY AND DRAINAGE BASIN
Community
Newcastle
Drainage Basin
______ .East Lake Washington -Bellevue South and May Creek
Part 6 SITE CHARACTERISTICS
D River D Floodplain
D Wetlands
D Stream D Seeps/Springs
D Critical Stream Reach D High Groundwater Table
D Depressions/Swales D Groundwater Recharge
D Lake X Other N/A -
D Steep Slopes
Part? SOILS
Soil Type
AgC
Slopes
5%±
D Additional Sheets Attached
Part 8 DEVELOPMENT LIMITATIONS
REFERENCE
D Ch. 4 -Downstream Analysis
0
D
D
D
D
D Additional Sheets Attached
Part 9 ESC REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
D Sedimentation Facilities
X Stabilized Construction Entrance
X Perimeter Runoff Control
D Clearing and Grading Restrictions
X Cover Practices
X Construction Sequence
D Other
Erosion Potential
LOW
Erosive Velcoties
LIMITATION/SITE CONSTRAINT
LEVEL 1/NO CONSTRAINT
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
X Stabilize Exposed Surface
D Remove and Restore Temporary ESC Facilities
X Clean and Remove All Silt and Debris
D Ensure Operation of Permanent Facilities
D Flag Limits of SAO and open space
preservation areas
D Other
Part 10 SURFACE WATER SYSTEM
D Grass Lined [] Tank LJ Infiltration Method of Analysis
Channel D Vault D Depression
!1 Pipe System Compensation/Mitigati L... D 1-Energy Dissapator cJ Flow Dispersal on of Eliminated Site D Open Channel D D Storage Wetland Waiver
11 Dry Pond D D Stream Regional
D Wet Pond Detention
Brief Description of System Operation _Basic Infiltration
__ Tightline To Existing City Storm System
Facility Related Site Limitations
Reference Facility Limitation
Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS
D Cast in Place Vault D Drainage Easement
D Retaining Wall D Access Easement
D Rockery > 4' High D Native Growth Protection Easement
D Structural on Steep Slope D Tract
D Other D Other
Part 13 SIGNATURE OF PROFESSIONAL ENGINEER
I or a civil engineer under my supervision my supervision have visited the site. Actual site
conditions as observed were incorporated into this worksheet and the attachments. To the best of
my knowledge the information provided here is accurate.
Sianed/Date
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VICINITY MAP
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2009 KC SWDM Core Requirements
Section 1.2.1 Core Requirement #1: Discharge at the natural location
• The proposed on-site drainage will be tightlined from the project site infiltration
BMPs into the existing storm drainage system in Lincoln Ave NE.
Section 1.2.2 Core Requirement #2: Offeite Analysis
• An offsite drainage analysis is provided in this Preliminary TIR.
Section 1.2.3 Core Requirement #3: Flow Control
• Analysis shows the BMPs will provide the required flow control.
Section 1.2.4 Core Requirement #4: Conveyance System
• The proposed project site will produce less than 10,000 square feet of impervious
surfaces and therefore it falls under the Small Project Drainage requirements. Flow
Control BMPs will be provided for future residence under a separate building permit.
Section 1.2.5 Core Requirement #5: Erosion and Sediment Control
• A temporary erosion control plan will provide BMPs to be implemented during
construction.
Section 1.2.6 Core Requirement #6: Maintenance and Operations
• A maintenance and operations manual will be provided in the TIR as determined with
City review of the final engineering plans/design.
Section 1.2. 7 Core Requirement #7: Financial Guarantees and Liability
• The developer will arrange for any financial guarantees and liabilities required by the
permit.
Section 1.2.8 Core Requirement #8: Water Quality
• There will be less than 5,000 sq-ft of new PGIS so water quality measures are not
needed.
2009 KC SWDM Special Requirements
Section 1.3.1 Special Requirement #1: Other Adopted Area-Specific Requirements
• NIA
Section 1.3.2 Special Requirement #2: Floodplain/Floodway Delineation
• NI A there are no FEMA floodplains/floodways in the area
Section 1.3.3 Special Requirement #3: Flood Protection Facilities
• NIA
Section 1.3.4 Special Requirement #4: Source Control
• Source control is not required for this project.
Section 1.3.5 Special Requirement #5: Oil Control
• NI A Oil control is not required for this project.
SECTION2
CONDITIONS AND REQUIREMENTS SUMMARY
SECTION3
OFF-SITE ANALYSIS
Project Overview
This project involves development of a 22,587 SF parcel into two single-family residential lots.
The existing parcel has an existing house, a sport court, a shed and the remaining area is covered
with several mature trees with lawn. The site slopes down to northwest at approximately 5%.
Per the SCS Soil maps, the site is underlain with Alderwood, gravelly sandy loam, AgC.
-See attached geotechnical report.
Downstream Drainage
Level 1 downstream analysis for this project was conducted on Jan 07, 2015. The weather on the
day of the site visit was cloudy with the temperature of approximately 45°F.
Runoff from the existing site generally sheet flows northwest and drains into an existing ditch
with 3:1 side slopes located along the east side of the Lincoln Ave NE at point A. From there
flow drains north through a 12-inch pipe and enters into another ditch with 3:1 side slopes
located at point 8. From there flow continues north through a 12-inch pipe and enters into a
ditch, then into a CB located at point C for a total of approximately 200-feet downstream from
the project site. From there, flow continues north though an 18-inch pipe and enters into a CB
located at point D for a total of 270-feet downstream from the project site. From there flow
continues north through an 18-inch pipe and enters into a CB located at point E for a total of
270-feet downstream from the project site. From there, flow continues north through pipes along
the east side of Lincoln Ave NE and enters into CB's at points F,G,H,I,J,K, and L for a total of
approximately 1,070-feet downstream from the project site. From the CB at point L flow crosses
the Lincoln Ave NE to west through an 18-inch pipe and drains into a vegetated ditch located at
point M. From there, flow continues north through the ditch and drains into 30-inch pipe at point
N for a total of 1,260-feet downstream from the project site. From there, flow continues north
through the pipe and crosses the NE 40th St and drains into a CB located at point O for a total of
1,350-feet downstream from the project site. From there, flow continues north through a 30-inch
pipe and outfall into a heavy vegetated channel at point P well beyond Y. mile downstream from
the project site, and eventually runoff discharges into the Lake Washington.
There were no obvious downstream drainage problems have been identified during this Level I
Downstream analysis. We understand that there are flooding issues beyond this Y, mile
downstream.
Please refer to the end of this section for downstream drainage map and photos.
DOWNSTREAM DRAINAGE MAP
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Renton
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Oat&: 1[7/2015 SOurce: ,(ng COunty iMAP -Property lr,tQfffl8tion (http:llwwwmetrokc.gav/GISJIMAPJ
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Photo 1: Ditch at point A
Photo 3: Ditch at point M
P hoto 2 : CB at point C
Photo 4 : Runoff discharges to a vegetated channel
at point P
SECTION 4
FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS
AND DESIGN
Drainage Design
The project consists of subdividing the existing 22,587 SF parcel into two (2) lots. It is proposed
to construct less than I 0,000 SF of total impervious surface, and therefore it is subject to Small
Project Drainage Review.
The total impervious surfaces for existing lot that will remain is less than 4,000 SF, and the
proposed new lot will create a total of approximately 4,000 SF of impervious surfaces.
Final design will be provided with the final engineering design/plan set. It is proposed that Basic
BMPs to be implemented for Flow Control based on the KCRTS analysis.
Water Quality BMPs
Water quality design is not required, because the total proposed impervious surfaces for new
project site will be less than 5,000 square feet.
KCRTS Analysis
Existing Conditions
Total Parcel area: 0.52 acres.
~ AiEx= 0
~ ApEx = 22,587 sq-ft= 0.52 acres till forest
~ Rainfall Regional Scale Factor= Seatac 1.0
Using KCRTS (see printout)
~ Q100-Ex = 0.42 CFS
Developed Conditions
Total Parcel area: 0.52 acres.
Total impervious area:
~ AioEv = 8,000 sq-ft= 0.18 acres ( includes existing and proposed impervious surfaces)
Total pervious area:
~ ApoEv = 0.34 acres till grass (Lawn)
Per 2009 KCSWDM Table 1.2.3.C Flow Control BMP Sizing Credits
Basic Dispersion/infiltration is modeled as 50% impervious and 50% grass
(Considering the total impervious/2=> {8,000+2=4,000 SF}
~ adjusted AioEv = 0.09 acres impervious surfaces
~ adjusted ApoEv = 0.09 acres till grass
~
Therefore: . •.
KCRTS inputs:
~ ApoEv = 0.43 acres till grass (Lawn)
~ AioEv = 0.09 acres impervious
Using KCRTS (see printout)
~ Q100-DEV= 0.133 CFS
L'i.Q100-Q100-0Ev -Q100-Ex= 0.133 -0.042 = .091 CFS
,/ AQ100< 0.1 CFS=> Detention is not required
BAIMA & HOLMBERG, INC.
100 Front Steet South
ISSAQUAH, WASHINGTON 98027 -3817
(425) 392-0250 FAX (425) 391-3055
SHEETNO. _________ OF ______ _
CALCULATEDBY ________ DATE ______ _
CHECKEOBY _________ DATE ______ _
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Flow Frequency Analysis
Time Series File:14694u.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--------Flow Frequency Analysis-------
Flow Rate Rank Time of Peak --
(CFS)
0.033 2 2/09/01 18:00
0.009 7 1/06/02 3:00
0.024 4 2/28/03 3:00
0.001 8 3/24/04 21:00
0.015 6 1/05/05 8:00
0.025 3 1/18/06 20:00
o. 021 5 11/24/06 4:00
0.042 1 1/09/08 9:00
Computed Peaks
KCRTS Developed Conditions Peaks
Flow Frequency Analysis
Time Series File:14694d.tsf
Project Location:Sea-Tac
Peaks Rank Return Prob
(CFS) Period
0.042 1 100.00 0 . 9 9 0 Clioo-ex
0.033 2 25.00 0. 960
0.025 3 10.00 0.900
0.024 4 5.00 0.800
o .021 5 3.00 0.667
0.015 6 2.00 0.500
0.009 7 1. 30 0.231
0.001 8 1.10 0.091
0.039 50.00 0. 98 0
---Annual Peak Flow Rates--------Flow Frequency Analysis-------
Flow Rate Rank Time of Peak --Peaks Rank Return Prob
(CFS) (CFS) Period
0.060 4 2/09/01 2:00 0.133 1 100.00 0 . 9 9 0 Clioo-oev
0.039 7 1/05/02 16:00 0.075 2 25.00 o. 960
0.075 2 2/27/03 7:00 0.063 3 10.00 0.900
0.030 8 8/26/04 2:00 0.060 4 5.00 0.800
0.039 6 10/28/04 16:00 0.058 5 3.00 0.667
0.063 3 1/18/06 16:00 0.039 6 2.00 0.500
0.058 5 11/24/06 3:00 0.039 7 1. 30 0.231
0 .133 1 1/09/08 6:00 0.030 8 1.10 0.091
Computed Peaks 0.114 50.00 0.980
l1Q100 -Q100 DEV -Q100 EX = 0 .133 -0. 042 = 0. 091 < .1 CFS
SHOISM:!111
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SECTION 5
CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Conveyance Analysis
Since the storm drain system is private systems serving regular single family residential facility,
conveyance system analysis is not required. The proposed pipes does not exceed 4 inch and 6
inch.
SECTION6
SPECIAL REPORTS AND STUDIES
Geotechnical Engineering Report
3616 Lincoln Avenue NE
Renton, Washington
P/N 3345700215
Submitted to:
Encompass Engineering and Surveying
Attn: Timothy Collins
165 NE Juniper St, Suite 201
Issaquah, Washington 98027
Submitted by:
E3RA, Inc.
PO Box44840
Tacoma, Washington 98448
(253) 537-9400
March 20, 2015
Project No. T15023
TABLE OF CONTENTS
Page No.
1.0 SITE AND PROJECT DESCRIPTION ................................................................................... 1
2.0 EXPLORATORY METHODS..................... .. ............................................ 2
2.1 Test Pit Procedures ..................................................................................................... 2
2.2 Test Hole Procedures .................................................................................................. 3
3.0 SITE CONDITIONS ................................................................................................................. 3
3.1 Surface Conditions ....................................................................................................... 3
3.2 Soil Conditions ........................................................................................................... 3
3.3 Groundwater Conditions .............................................................................................. 4
3.4 Seismic Conditions ...................................................................................................... 4
3.5 Liquefaction Potential .............................. .. .................................... 4
3 6 Infiltration Conditions and Infiltration Rate ................................................................. 4
4.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................................... 5
4.1 Site Preparation ....................................................................................................... 6
4.2 Spread Footings ........................................................................................................ 8
4.3 Slab-On-Grade Floors ................................................................................................ 9
4.4 Drainage Systems ........................................................................................................ 9
4.5 Asphalt Pavement.. .............................................................................................. 10
4.6 Structural Fill......................................................... .. ............................. 11
5.0 RECOMMENDED ADDITIONAL SERVICES ........................................................................ 12
6.0 CLOSURE ............................................................................................................................ 12
List of Tables
Table 1. Approximate Locations and Depths of Explorations ....
Table 2. Laboratory Test Results for Non-organic Onsite Soils
List of Figures
Figure 1. Topographic and Location Map
Figure 2. Site and Exploration Plan
APPENDIX A
Soil Classification Chart and Key to Test Data ..
Test Pit Log TP-1
Log of Test Hole TH-1
APPENDIXB
Laboratory Testing Results
. .......... 2
.................. 5
. ............... A-1
....... A-2
... A-3
......... 8-1 ... 8-4
March 20, 2015
Tl5023
Encompass Engineering and Surveying
165 NE Juniper St, Suite 201
Issaquah, WA 98027
Attention:
Subject:
Timothy Collins
Geotechnical Engineering Report
Tax Parcel -3345700215
Residential Plat
3616 Lincoln Ave NE
Renton, Washington
Dear Mr. Collins:
PO Box 44840
Tacoma, WA 98448
253-537-9400
253-537-9401 Fax
E3RA, Inc. (E3RA) is pleased to submit this report describing the results of our geotechnical engineering
evaluation of the improvements planned for the residential lot located at 3616 Lincoln Ave NE in Renton,
Washington.
This report has been prepared for the exclusive use of Encompass Engineering and Surveying, and their
consultants, for specific application to this project, in accordance with generally accepted geotechnical
engineering practice.
1.0 SITE AND PROJECT DESCRIPTION
The project site consists of a rectangular shaped residential parcel located directly northeast of the intersection
of Lincoln Ave NE and NE 36th Street in Renton, Washington as shown on the enclosed Topographic and
Location Map (Figure I). It is bounded on the west by Lincoln Ave NE, the south by NE 36th Street, the east
by Lincoln Ct NE, and on the north by a residential parcel, encompassing just over a Y, acre.
Visually, the parcel is easily divided into two distinct areas; the west half and east half. Located centrally
within the west half of the property is the existing single family residence; which is wood-framed, two-stories,
and was originally constructed in 1993. Extending to the residence from Lincoln Ave NE is a concrete
driveway, with areas north of the driveway serving as the front lawn, and areas south of the driveway
containing a gravel surfacing that acts as overflow parking/storage. A small shed building is located directly
south of the residence. The east half of the parcel is what would be considered the backyard area and is
entirely contained within a large wooden fence. The north half of the east side of the property contains an
athletic court used apparently for basketball or tennis, with nets being erected on either side of the court. The
south half of the east end of the parcel is predominantly occupied by an open grassy lawn. Areas between the
residence and athletic court and/or lawn area are occupied by gravel walkways and landscaping features.
March 20, 2015
T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
Preliminary plans involve the short-plat of the parcel, with the property being divided east/west into two
residential lots designated Lot I and Lot 2. Lot 1 will contain the existing single family residence, while Lot 2
will contain what currently consists of the athletic court and back lawn area. It is our assumption that a new
residence will be constructed in Lot 2, and we do not know if the existing residence will be demolished or
retained.
2.0 EXPLORATORY METHODS
We explored surface and subsurface conditions at the project site on March 5, 20 l 5. Our exploration program
comprised the following elements:
A surface reconnaissance of the site;
One Test Pit Exploration (designated TP-l) performed in the southwest comer of the site;
One Test Hole Exploration (designated TH-I) performed in the east end of the site;
Two grain size analyses performed on soil samples collected from our subsurface
explorations; and
A review of published geologic and seismologic maps and literature.
Table l summarizes the approximate functional locations and termination depths of our subsurface
explorations, and Figure 2 depicts their approximate relative locations. The following sections describe the
procedures used for excavation of test pits.
TABLE 1
APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS
Termination
Exploration Functional Location Depth
(feet)
TP-1 Southwest comer of the site 11
TH-1 Southeast comer of the site 6
The specific number and locations of our explorations were selected in relation to the existing site features,
under the constraints of surface access, underground utility conflicts, and budget considerations.
ft should be realized that the explorations performed and utilized for this evaluation reveal subsurface
conditions only at discrete locations across the project site and that actual conditions in other areas could vary.
Furthermore, the nature and extent of any such variations would not become evident until additional
explorations are performed or until construction activities have begun. If significant variations are observed
at that time, we may need to modify our conclusions and recommendations contained in this report to reflect
the actual site conditions.
Test Pit Procedures
Our exploratory test pit was excavated with a rubber-tracked excavator owned and operated by an excavation
contractor under subcontract to E3RA. An engineering geologist from our firm observed the test pit
excavation and logged the subsurface conditions.
2
March 20, 2015 E3RA, Inc.
T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
The enclosed test pit log indicate the vertical sequence of soils and materials encountered in the test pit, based
on our field classifications. Where a soil contact was observed to be gradational or undulating, our log
indicates the average contact depth. We estimated the relative density and consistency of the in-situ soils by
means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the
approximate depths of any sidewall caving or groundwater seepage observed in the test pit. The soils were
classified visually in general accordance with the system described in Figure A-1, which includes a key to the
exploration log. A summary log of the exploration is included as Figure A-2.
Test Hole Procedures
Our exploratory test hole was excavated with a shovel, post hole digger, iron bar, and 3 inch hand auger by an
engineering geologist from EJRA, who also logged the subsurface conditions.
The enclosed test hole log indicates the vertical sequence of soils and materials encountered in the test hole,
based on our field classifications. Where a soil contact was observed to be gradational or undulating, our log
indicates the average contact depth. We estimated the relative density and consistency of the in-situ soils by
means of the excavation characteristics and the stability of the test pit sidewalls. Samples of soils were
collected. Our log also indicates the approximate depths of the samples collected and any sidewall caving or
groundwater seepage observed. The soils were classified visually in general accordance with the system
described in Figure A-1, which includes a key to the exploration log. A summary log of the exploration is
included as Figure A-3.
3,0 SITE CONDITIONS
The following sections present our observations, measurements, findings, and interpretations regarding,
surface, soil, groundwater, seismic, and liquefaction conditions.
Surface Conditions
As previously described, development plans involve the sub-plat of the subject property into two residential
lots designated Lot I and Lot 2. Lot 1 or the westernmost lot is predominately level, with only a slight slope
proponent near the western and northern margins of the parcel, towards the west and north, respectively. Lot 2
is also predominately level, containing a slight slope element towards its northern boundary, representing an
elevation change of 3 to 5 feet. The grassy lawn area in the southeast comer of the site was constructed
approximately 2 to 3 feet higher than that of adjacent grades, with concrete steps being constructed along its
northern extent to provide access to the area.
Vegetation on site consists primarily of ornamental lawns, trees and shrubs. Larger growths of trees/shrubs
line the western, southern and eastern margins of the site.
No hydrologic features were observed on site, such as seeps, springs, ponds and streams.
Soil Conditions
Our subsurface explorations encountered relatively consistent soil conditions across the project site. In the
vicinity of test pit exploration TP-1, performed in the southwest comer of the site, we observed that a surface
mantle of 12 inches of pea gravel covers this portion of the project area. The original topsoil horizon was
encountered immediately beneath the gravel surfacing, and is underlain by native, sandy soils. From a depth of
l V, to 8 1
/, feet below existing grade we encountered fine, silty sand in a medium dense in-situ condition, with
the upper 3 Y, feet of these deposits displaying mottling. From SY, to 11 feet below grade, the termination depth
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T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
for this exploration, soils transitioned to fine sand with silt. Sieve analyses performed on each of these distinct
soil groups indicate that the upper deposits contain a fines (percent silt'clay) content in excess of JO percent,
while the deeper deposits contain a fines content of less than 8 percent.
Test hole exploration TH-I encountered similar sandy soils with depth, but a thicker, surficial topsoil horizon.
The attached exploration logs provide a detailed description of the soil strata encountered in our subsurface
explorations.
Groundwater Conditions
At the time of our site reconnaissance and subsurface explorations, we did not encounter groundwater in any of
our explorations, which extended to a nominal depth of 11 feet below existing grades. Given the fact that our
subsurface explorations were performed during what is generally considered the wet season (October !st
through April JOlh), we do not anticipate that groundwater levels will rise higher than that which we observed,
nor do we anticipate that groundwater will adversely affect proposed earthwork activities. Groundwater levels
will fluctuate with localized precipitation and geology.
Seismic Conditions
Based on our analysis of subsurface exploration logs and our review of published geologic maps, we interpret
the onsite soil conditions to generally correspond with site class D, as defined by Table 20.3-1 inASCE 7, per
the 2012 International Building Code (!BC).
Using 2012 !BC information on the USGS Design Summary Report website, Risk Category I/II/III seismic
parameters for the site are as follows:
S, = 1.437g SMs = 1.437g Sos= 0.958g
S1 = 0.545g SM1 = 0.818g Soi= 0.545g
Using the 2012 !BC information, MCER Response Spectrum Graph on the USGS Design Summary Report
website, Risk Category I/II/III, S,at a period of0.2 seconds is 1.44g and S,at a period of 1.0 seconds is 0.82g.
The Design Response Spectrum Graph from the same website, using the same !BC information and Risk
Category, S,at a period of0.2 seconds is 0.96g and S,at a period of 1.0 seconds is 0.55g.
Liguefaction Potential
Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by
shear strains, as could result from an earthquake. Research has shown that saturated, loose sands with a fines
(silt and clay) content less than about 20 percent are most susceptible to liquefaction. Our onsite subsurface
explorations did not reveal saturated (or potentially saturated), loose, silty sand layers or lenses.
Infiltration Conditions and Infiltration Rate
At the time of report preparation, it is not known whether onsite infiltration will be incorporated into the
project storm water management plan, nor, if it is the size, location, or dimensions of new facilities. If onsite
infiltration is implemented as part of the new development, we offer the following recommendations.
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T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
Based on our field observations and grain size analyses (presented in Table 2, below), two distinct soil stratum
are available on site as medium for possible infiltration. The upper native deposits consist of fine silty sand,
with fines content in excess of30 percent. At a depth of8Y, feet below existing grade, more readily penneable
sandy soils are encountered with a fines content less than 8 percent.
The results of our soil grain size analyses are presented below, and the attached Soil Gradation Graphs
(Appendix B) display the grain-size distribution of the samples tested.
TABLE2
LABORATORY TEST RESULTS FOR NON-ORGANIC ONSITE SOILS
Soil Sample, Depth % Coarse % Fine % Coarse %Medium % Fine % Fines D10 Gravel Gravel Sand Sand Sand
TP-1, S-1, 3 feet 0 6.4 0.4 2.5 60.3 30.4 -
TP-1. S-3, 9 feet 0 0 0.4 1.1 90.9 7.6 0.08
Preliminary Recommended Infiltration Rate
Specific locations and geometry of infiltration facilities for the project site had not been detennined at the time
this report was prepared. Therefore, we have provided a generalized infiltration rate for use in preliminary
design of any future infiltration facilities planned in the site area. If onsite infiltration is implemented,
infiltration testing is recommended in the vicinity of new facilities at or near their proposed invert elevations.
We detennined a preliminary infiltration rate for the project site by comparing the results of our sieve analyses
from test pit exploration TP-1 with Table 3.7, in Volume III of the 2005 DOE Stormwater Management
Manual for Western Washington, located on page 3-76. Using the U.S.D.A. Textural Triangle, the upper soil
deposits are classified as sandy loam and the deeper deposits are classified as sand with corresponding
recommended long-tenn infiltration rates of0.25 in/hr and 2 in/hr respectively.
4.0 CONCLUSIONS AND RECOMMENDATIONS
Plans call for the sub-plat of an existing residential parcel in Renton, Washington and the construction of a new
single family residence with associated paved surfaces for the driveway and parking. We offer these general
conclusions and recommendations:
Erosion Hazards: Most of the site presents a moderate erosion hazard. Standard erosion
control measures, such as silt fences or mulch benns, temporary protection of bare soils with
plastic, mulch, or other cover, and pennanent re-vegetation of bare soils, is recommended.
Erosion control recommendations are made in the Site Preparation section in Section 4.1.
Foundation Options: We recommend conventional spread footings that bear on medium
dense or denser native soils, which are generally found within a few feet of the surface of the
site. Recommendations for spread footings are provided in Section 4.2.
Floor Options: We recommend concrete slab-on-grade floors for the structure.
Recommendations for slab-on-grade floors are included in Section 4.3.
Drainage Considerations: We recommend that perimeter drains be placed around foundation
footings. Recommendations for drainage systems are included in Section 4.4.
Pavement Sections: Native, in-situ soil conditions are amenable to the use of soil-supported
pavements. We recommend a conventional pavement section comprised of an asphalt
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concrete pavement over a crushed rock base course over a properly prepared ( compacted)
subgrade or a granular subbase, depending on subgrade conditions during pavement subgrade
preparation.
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump
truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this
proof-rolling operation should be overexcavated to a depth of 12 inches and replaced with a
suitable structural fill material.
Infiltration Recommendations: If infiltration of site produced stormwater becomes
incorporated into the new development, we recommend using a preliminary infiltration rate of
0.25 in/hr for the upper, siltier soils, and a rate of 2 in/hr for the lower (those encountered
below 8Y, feet bgs), sandier soils. If infiltration is implemented, we recommend infiltration
testing in the vicinity ofnew facilities.
The following sections present our specific geotechnical conclusions and recommendations concerning site
preparation, spread footings, slab-on-grade floors, drainage, subgrade walls, temporary shoring, and structural
fill. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard
Plans cited herein refer to WSDOT publications M4 I-10, Standard Specifications for Road, Bridge, and
Municipal Construction, and M21-0I, Standard Plans for Road, Bridge, and Municipal Construction,
respectively.
Site Preparation
Preparation of the project site should involve erosion control, temporary drainage, clearing, stripping, cutting,
filling, excavations, and subgrade compaction.
Erosion Control: Before new construction begins, an appropriate erosion control system should be installed.
This system should collect and filter all surface run off from the construction areas through silt fencing. We
anticipate a system of berms and drainage ditches around construction areas will provide an adequate collection
system. Silt fencing fabric should meet the requirements ofWSDOT Standard Specification 9-33.2 Table 3.
In addition, silt fencing should embed a minimum of 6 inches below existing grade. An erosion control system
requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has
shifted above ground surface should be replaced or repaired as soon as they are identified.
As an alternative, mulch-type berms, such as described in the latest Washington Department ofEcology Storm
Water Manual, can be deployed immediately down slope of construction areas until vegetation has been
re-established there.
Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or
near-surface water within the construction zones before stripping begins. Because the selection of an
appropriate drainage system will depend on the water quantity, season, weather conditions, construction
sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the
time of construction. Based on our current understanding of the construction plans, surface and subsurface
conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept
surface water runoff.
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Clearing and Stripping: After surface and near-surface water sources have been controlled, the construction
areas should be cleared and stripped of all sod, topsoil, and root-rich soil. Based on our subsurface
explorations, the organic laden horizon can be upwards of 24 inches thick within the project area.
Site Excavations: Based on our explorations, we expect that site excavations will encounter moderately dense
sandy soils which can readily excavated using standard equipment.
Dewatering: Our explorations did not encounter groundwater within their termination depths, nor do we
expect that groundwater will be present in the planned excavations. However, if groundwater is encountered,
we anticipate that an internal system of ditches, sump holes, and pumps will be adequate to temporarily
dewater excavations.
Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be
adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper
than I Y, H: 1 V, and should conform to Washington Industrial Safety and Health Act (WISHA) regulations.
Subgrade Compaction: Exposed subgrades for footings, slabs, and floors should be compacted to a firm,
unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils
observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In
contrast, any organic, soft, or pumping soils observed within a subgrade should be overexcavated and replaced
with a suitable structural fill material. Surface compaction ofall footing and slab subgrades is recommended,
although surface compaction could become problematic during wet weather conditions or when in situ site
soils become wet.
Site Filling: Our conclusions regarding the reuse of onsite soils and our comments regarding wet-weather
filling are presented subsequently. Regardless of soil type, all fill should be placed and compacted according
to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill
soil should be compacted to a uniform density of at least 95 percent (based on ASTM 0-1557).
Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural
fill:
Surficial Organic Soils: The topsoil and root-rich soil that overlies the site is not suitable for
use as structural fill under any circumstances, due to high organic content.
Fine Silty Sand and Fine Sand with Silt: Our subsurface explorations reveal that native soils
on site consist of fine silty sand and fine sand with silt. Each soil type contains a significant
fines proponent (percent si!Vclay), and will be moisture sensitive. Reusing this material type
as structural fill will become increasing difficult in wet weather conditions.
Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term
raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H: IV.
For all soil types, the use of flatter slopes (such as 2Y,H: IV) would further reduce long-term erosion and
facilitate revegetation.
Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the top edge of
all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as
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T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
soon as foasible, to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could
be armored with quarry spalls or a geosynthetic erosion mat.
Spread Footings
In our opinion, conventional spread footings will provide adequate support for the proposed structure if the
subgrades are properly prepared.
Footing Depths and Widths: For frost and erosion protection, the bases ofall exterior footings should bear at
least l 8 inches below adjacent outside grades, whereas the bases of interior footings need bear only 12 inches
below the surrounding slab surface level. To reduce post-construction settlements, continuous (wall) and
isolated (column) footings should be at least 18 and 24 inches wide, respectively.
Bearing Subgrades: Footings should bear on medium dense or denser, undisturbed native soils oron properly
compacted structural fill which bears on undisturbed medium dense or very dense native soils. In general,
before footing concrete is placed, any localized zones of loose soils exposed across the footing subgrades
should be compacted to a firm, unyielding condition, and any localized zones of soft, organic, or debris-laden
soils should be overexcavated and replaced with suitable structural fill. We recommend vigorous surface
compaction of footing subgrades to a medium dense or denser condition.
Subgrade Observation: All footing subgrades should consist of firm, unyielding, native soils or structural fill
materials compacted to a density of at least 95 percent (based on ASTM:D-1557). Footings should never be
cast atop loose, soft, or frozen soil, slough, debris, existing uncontrolled fill, or surfaces covered by standing
water.
Bearing Pressures: In our opinion, for static loading, footings that bear on properly prepared subgrades can be
designed for a ma~imum allowable soil bearing pressure of2,000 pounds per square foot (psf). A one-third
increase in allowable soil bearing capacity may be used for short-term loads created by seismic or wind related
activities.
Footing Settlements: Assuming that structural fill soils are compacted to a medium dense or denser state, we
estimate that total post-construction settlements of properly designed footings bearing on properly prepared
subgrades will not exceed I inch. Differential settlements for comparably loaded elements may approach
one-half of the actual total settlement over horizontal distances of approximately 50 feet.
Footing Backfill: To provide erosion protection and lateral load resistance, we recommend that all footing
excavations be backfilled on both sides of the footings and stemwalls after the concrete has cured. Either
imported structural fill or non-organic onsite soils can be used for this purpose, contingent on suitable moisture
content at the time of placement. Regardless of soil type, all footing backfill soil should be compacted to a
density of at least 90 percent (based on ASTM:D-1557).
Lateral Resistance: Footings that have been properly backfilled as recommended above will resist lateral
movements by means of passive earth pressure and base friction. We recommend using an allowable passive
earth pressure of275 pcfand an allowable base friction coefficient of0.35.
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4.3 Slab-On-Grade Floors
In our opinion, soil-supported slab-on-grade floors can be used in the proposed structure if the subgrades are
properly prepared. We offer the following comments and recommendations concerning slab-on-grade floors.
Floor Subbase: Structural fill subbases do not appear to be needed under soil-supported slab-on-grade floors
at the site. However, the final decision regarding the need for subbases should be based on actual subgrade
conditions observed at the time of construction. If a subbase is needed, all subbase fill should be compacted
to a density of at least 95 percent (based on ASTM:D-1557). AU subgrades should be vigorously surface
compacted to a medium dense or denser condition before slab construction begins.
Capillarv Break and Vapor Barrier: To retard the upward wicking of groundwater beneath the floor slab, we
recommend that a capillary break be placed over the subgrade. Ideally, this capillary break would consist ofa
6-inch-thick layer of pea gravel or other clean, uniform, well-rounded gravel, such as "Gravel Backfill for
Drains" per WSDOT Standard Specification 9-03.12( 4 ), but clean angular gravel can be used if it adequately
prevents capillary wicking. In addition, a layer of plastic sheeting (such as Crosstuff, Visqueen, or Moistop)
should be placed over the capillary break to serve as a vapor barrier. During subsequent casting of the concrete
slab, the contractor should exercise care to avoid puncturing this vapor barrier.
Vertical Deflections: Due to elastic compression of subgrades, soil-supported slab-on-grade floors can deflect
downwards when vertical loads are applied. In our opinion, a subgrade reaction modulus of 250 pounds per
cubic inch can be used to estimate such deflections.
4.4 Drainage Systems
In our opinion, the planned structure should be provided with permanent drainage systems to reduce the risk of
future moisture problems. We offer the following recommendations and comments for drainage design and
construction purposes.
Perimeter Drains: We recommend that structures be encircled with a perimeter drain system to collect seepage
water. This drain should consist of a 6-inch-diameter perforated pipe within an envelope of pea gravel or
washed rock, extending at least 6 inches on all sides of the pipe, and the gravel envelope should be wrapped
with filter fabric to reduce the migration of fines from the surrounding soils. Ideally, the drain invert would be
installed no more than 8 inches above the base of the perimeter footings.
Subfloor Drains: Based on the groundwater conditions observed in our site explorations, we do not infer a
need for subfloor drains.
Discharge Considerations: If possible, all perimeter drains should discharge to a storm sewer system or other
suitable location by gravity flow. Check valves should be installed along any drainpipes that discharge to a
sewer system, to prevent sewage backflow into the drain system. If gravity flow is not feasible a pump system
is recommended to discharge any water that enters the drainage system.
Runoff Water: Roof-runoff and surface-runoff water should not discharge into the perimeter drain system.
Instead, these sources should discharge into separate tightline pipes and be routed away from the building to a
storm drain or other appropriate location.
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Grading and Capping: Final site grades should slope downward away from the buildings so that runoff water
will flow by gravity to suitable collection points, rather than ponding near the building. [deally, the area
surrounding the building would be capped with concrete, asphalt, or low-permeability (silty) soils to minimize
or preclude surface-water infiltration.
4.5 Asphalt Pavement
We offer the following comments and recommendations for asphalt pavement design and construction.
Subgrade Preparation: Structural fill subbases do not appear to be needed under pavements at the site.
However, the final decision regarding the need for sub bases should be based on actual subgrade conditions
observed at the time of construction. If a subbase is needed, all subbase fill shou[d be compacted to a density
ofat least 95 percent (based on ASTM:D-1557).
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy
compactor. Any localized zones of yielding subgrade disclosed during this proof-ro[]ing operation should be
over excavated to a minimum depth of 12 inches and replaced with a suitable structural fill material. All
structural fill should be compacted according to our recommendations given in the structural fill section.
Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 95 percent
(based on ASTM D-l 557), and all soils below 2 feet should be compacted to at least 90 percent.
Pavement Materials: For the base course, we recommend using imported crushed rock, such as "Crushed
Surfacing Top Course" per WSDOT Standard Specification 9-03.9(3). If a subbase course is needed, we
recommend using imported, clean, well-graded sand and gravel such as "Ballast" or "Gravel Borrow" per
WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively.
Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete
pavement over a crushed rock base course. We recommend using the following conventional pavement
sections:
Pavement Course
Asphalt Concrete Pavement
Crushed Rock Base
Granular Fill Subbase (if needed)
Parking Areas
2 inches
4 inches
6inches
Minimum Thickness
Access Roads and Areas Subject to
Truck Traffic
3inches
6 inches
12 inches
Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent
of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted
to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an E3RA representative be
retained to observe the compaction of each course before any overlying layer is placed. For the subbase and
pavement course, compaction is best observed by means of frequent density testing. For the base course,
methodology observations and hand-probing are more appropriate than density testing.
Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described pavement
sections present our minimum recommendations for an average level of performance during a 20-year design
life; therefore, an average level of maintenance will likely be required. Furthermore, a20-yearpavement life
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T15023 I Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
typically assumes that an overlay will be placed after about 10 years. Thicker asphalt and/or thicker base and
subbase courses would offer better long-term performance, but would cost more initially; thinner courses
would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be
considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and
higher maintenance costs.
4.6 Structural Fill
The term "structural fill" refers to any material placed under foundations, retaining walls, slab-on-grade floors,
sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning
structural fill are presented in the following paragraphs.
Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock,
well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit-run"), and miscellaneous
mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing
the parent materials, are also potentially useful as structural fill in certain applications. Soils used for structural
fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches in
diameter.
Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be placed in
horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a
mechanical compactor.
Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that
structural fill used for various onsite applications be compacted to the following minimum densities:
Fill Application
Footing subgrade and bearing pad
Foundation backfill
Slab-on-grade floor subgrade and subbase
Asphalt pavement base and subbase
Asphalt pavement subgrade (upper 2 feet)
Asphalt pavement subgrade (below 2 feet)
Minimum Compaction
95 percent
90 percent
95 percent
95 percent
95 percent
• 90 percent
Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill should
be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this
report. The condition of all subgrades should be observed by geotechnical personnel before filling or
construction begins. Also, fill soil compaction should be verified by means ofin-place density tests performed
during fill placement so that adequacy of soil compaction efforts may be evaluated as earthwork progresses.
Soil Moisture Considerations: 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.
For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that
have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve.
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March 20, 2015 E3RA, Inc.
T15023 / Encompass Engineering -Lincoln Ave Geotechnical Engineering Report
5.0 RECO!VIMENDED ADDITIONAL SERVICES
Because the future performance and integrity of the structural elements will depend largely on proper site
preparation. drainage, fill placement, and construction procedures, monitoring and testing by experienced
geotechnical personnel should be considered an integral part of the construction process. Consequently, we
recommend that E3RA be retained to provide the following post-report services:
Provide design plans for temporary basement shoring walls, if needed;
Review all construction plans and specifications to verify that our design criteria presented in
this report have been properly integrated into the design;
Prepare a letter summarizing all review comments (ifrequired);
Check all completed subgrades for footings and slab-on-grade floors before concrete is
poured. in order to verify their bearing capacity; and
Prepare a post-construction letter summarizing all field observations, inspections, and test
results (if required).
6.0 CLOSURE
The conclusions and recommendations presented in this report are based, in part, on the explorations that we
observed for this study; therefore, if variations in the subgrade conditions are observed at a later time, we may
need to modify this report to reflect those cilanges. Also, because the future performance and integrity of the
project elements depend largely on proper initial site preparation, drainage, and construction procedures,
monitoring and testing by experienced geotechnical personnel should be considered an integral part of the
construction process. E3RA is available to provide geotechnical monitoring of soils throughout construction.
We appreciate the opportunity to be of service on this project. If you have any questions regarding this report
or any aspects of the project, please feel free to contact our office.
Sincerely,
E3RA, Inc.
Zach L. Logan
Staff Geologist
ZLL;JEB:jb
James E. Brigham, P.E.
Principal Engineer
T ACOZ:i2015 JOB F[LES\Tt5023 Encompass -Lincoln Ave Geotech,TJ5023 Encompass Engineering -Lincoln Ave Geotech Report.doc
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BOUNDARY AND TOPOGRAPHY ARE BASED ON
MAPPING PROVIDED TO E3RA AND OBSERVATIONS
MADE IN THE FIELD. THE INFORMATION SHOWN DOES
NOT CONSTITUTE A FIELD SURVEY BY E3RA.
TEST HCLE LCCATICNS
TH-1
0
I
WJ' Tacoma, WA 98448
253-537-9400
253-537-9401 fax
www.e3ra.com
PROJECT: 3616 Lincoln Ave NE
Renton, Washington
SHEET TITLE: Site and Ex:ploration Plan
DESIGNER: CRL JOB NO.T15023
DRAWN BY: CRL SCALE: As Shown
CHECKED BY JEB FIGURE:2
DATE: Mar.11, 2015 FILE: T15023.dw_R
APPENDIX A
SOIL CLASSIFICATION CHART AND
KEY TO TEST DATA
LOGS OF TEST PITS
<L
" ~ s
<g
~ z a
8 z z
!
<
0
'11 • > ~ • i5 • '" 0
0 al
UJ " z ,
~ " <!l r
UJ C
'" l" 0: -" ~ 0 O
() :;
~ ~ ·en
i5 0 ~~
UJ V
MAJOR DIVISIONS
I
CLEAN GRAVELS
GRAVELS WITH LITTLE OR
NO FINES
MORE THAN HALF
COARSE FRACTION
IS LARGER THAN
N0.4SIEVE GRAVELS WITH
OVER 15% FINES
CLEAN SANOS
SANDS WITH LITTLE
ORNO FINES
MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN
SANDS WITH N0.4SIEVE
OVER 15% FINES
SILTS AND CLAYS
LIQUID LIMIT LESS THAN 50
TYPICAL NAMES
19_-:1
GW ·,.1•· WELL GRADED GRAVELS. GRAVEL·SANO MIXTURES ~:-~:
i:t--:'\
GP ·,.e,~ POORLY GRADED GRAVELS. GRAVEL-SAND MIXTURES
;o·.t):
GM
GC
•·. SW:-
~ ....
· ..
SM.::.· .. ·-: •··.
SC
ML
SIL TY GRAVELS. POORLY GRADED GRAVEL-SAND-SILT
MIXTURES
CLAYEY GRAVELS. POORLY GRADED GRAVEL-SAN~LAY
MIXTURES
WELL GRADED SANDS. GRAVELLY SANOS
POORLY GRADED SANDS, GRAVELLY SANOS
SIL TY SANOS, POOORLY GRADED SANO-SILT MIXTURES
CLAYEY SANOS, POORLY GRADED SAND-CLAY MIXTURES
INORGANIC SIL TS AND VERY FINE SANDS, ROCK FLOUR.
SIL TY OR CLAYEY FINE SANDS. OR CLAYEY SILTS WITH
SLIGHT PLASTICITY Ell~ l-
-=IN=O.::.R.:.GAN=.:.IC-=C-LA_Y_S_O_F_L_O_w_T_O_M_E_D_IU_M_P_LA_s_n_c_1TY_. __ ---I GRAVELL Y CLAYS, SANDY CLAYS, SIL TY CLAYS,
LEAN CLAYS
QL 1--_: ORGANIC CIAYSANO ORGANIC SIL TY CLAYS OF LOW
PLASTICITY
z~r----------------~~~~nff--------------------~ ;j'! ii INORGANIC SILTS. MICACEOUS OR DIATOMACIOUS FINE
e> ~ SANDY OR SILTY SOILS, ELASTIC SILTS UJ £
z • SIL TS AND CLAYS
U:: ~ INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
LIQUID LIMIT GREATER THAN 50
HIGHLY ORGANIC SOILS
B Modified California
IS] Split Spoon • Pushed Shelby Tube
[I] Auger Cuttings
~ Grab Sample • Sample Attempt with No Recovery
CA Chemical Analysis
CN Consolidation
CP Compaction
OS Direct Shear
PM Permeability
pp Pocket Penetrometer
OH ~ ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ffi ORGANIC SIL TS
pt !i. ,,1/ PEATANDOTHERHIGHLYORGANICSOILS
RV R-Value
SA Sieve Analysis
SW Swell Test
TC Cyclic Triaxial
TX Unconsolidated Undrained Triaxial
TV Torvane Shear
UC Unconfined Compression
(1.2) (Shear Strength, ksf)
WA Wash Analysis
(20) (with % Passing No. 200 Sieve)
'if_ Water Level at Time of Drilling
.J_ Water Level after OriUing(with date measured)
SOIL CLASSIFICATION CHART AND KEY TO TEST DATA
FigureA-1
s'----------------------------------------------------"
~
" ;
w
~
~
" §
z z z
~
0
U) • ~ ~ 0 ·a
U) 0
" al w " ., ' ;i; ;.
CJ I
W C
"' Jg "' -.,: ~ 0 o
u "
B
IS] • Ill
~ • CA
CN
CP
OS
PM
pp
MAJOR DIVISIONS
!
' CLEAN GRAVELS
GRAVELS WITH LITTLE OR
NO FINES
MORE THAN HALF
COARSE FRACTION
IS LARGER THAN
GRAVELS WITH N0.4SIEVE
OVER 15% FINES
CLEAN SANDS
SANDS WITH LITTLE
ORNO FINES
MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN
SANDS WITH N0.4SIEVE
OVER 15% FINES
SIL TS AND CLAYS
LIQUID LIMIT LESS THAN 50
SILTS AND CLAYS
LIQUID LIMIT GREATER THAN 50
HIGHLY ORGANIC SOILS
Modified California
Split Spoon
Pushed Shelby Tube
Auger Cuttings
Grab Sample
Sample Attempt with No Recovery
Chemical Analysis
Consolidation
Compaction
Direct Shear
Penneability
Pocket Penetrometer
TYPICAL NAMES
WELL GRADED GRAVELS, GRAVEL-SANO MIXTURES
0""'<·1·
GP )SD:
e·.~.
POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES
SIL TY GRAVELS, POORLY GRADED GRAVEL-SAND-SILT
MIXTURES
GC , , CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY
"I MIXTURES
WELL GRADED SANDS, GRAVELLY SANOS
SP I:/ :. :. POORLY GRADED SANDS, GRAVELLY SANOS
SM :··: ·: SILTY SANDS, POOORLYGRADEDSANO-SILTMIXTURES
SC ~ ·i CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES ,,
INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR,
ML SIL TY OR CLAYEY FINE SANOS, DR CLAYEY SIL TS WTH
SLIGHT PLASTICITY
INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,
GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS,
LEAN CLAYS
OL ~ -ORGANICCLAYSANDORGANICSILTYCLAYSOFLOW
PLASTICITY
MH
CH
OH
INORG.8.NIC SIL TS, MICACEOUS OR DIATOMACIOUS FINE
SANDY OR SIL TY SOILS, ELASTIC SILTS
INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY.
ORGANIC SILTS
pt ~ ~' 1/ PEAT AND OTHER HIGHLY ORGANIC SOILS
RV R-Value
SA Sieve Analysis
SW Swell Test
TC Cyclic Triaxial
TX Unconsolidated Undrained Triaxial
TV Torvane Shear
UC Unconfined Compression
(1.2) {Shear Strength, ksf)
WA Wash Analysis
(20) (with % Passing No. 200 Sieve)
'5l. Water Level at Time of Drilling
:t: Water Level after Drilling(with date measured)
SOIL CLASSIFICATION CHART AND KEY TO TEST DATA
Figure A-1
"'----------------------------------------------------'
E3RA, Inc. TEST PIT NUMBER TP-1
j E3 RA, Inc. j
P.O. Box44840
PAGE 1 OF 1 Tacoma, WA 98448 Figure A-2 Telephone: 253-537-9400
t. Fax: 253-537-9401
CLIENT Encom~ss Engineering & Su_rveyi_n_g_ PROJECT NAME 3616 Lincoln Ave_NE ··--
PROJECT NUMBER T15023 PROJECT LOCATION Renton_, Washinmon ---
DATE ST ART ED 3/5/15 COMPLETED J/5/15 GROUND ELEVATION TEST PIT SIZE
EXCAVATION CONTRACTOR DSE GROUND WATER LEVELS:
EXCAVATION METHOD Steef Tracked Excavator AT TIME OF EXCAVATION
LOGGED BY Zll CHECKED BY _.J_EB AT END OF EXCAVATION -
NOTES AFTER EXCAVATION
UJ a. 0 :,: /: ffi ui 'i: CJ >--UJ "' (,) a."' ...,::; a. 0 MATERIAL DESCRIPTION UJ-"' c2..., 0 a. ::, ::i ::ez CJ <(
"' 0.0
§~ E
(GP) Gray gravel with sand and trace silt (loose, moist) (Fill)
. GP
w
~ 1.0 ~---
r SM i (SM) Dark brown silty sand with some gravel, copious organics, and small root complexes (loose, moist) (Topsoil Horizon)
~ 1.5 w ~ r (SM) Tan mottled fine silty sand (medium dense, moist) 0 z < r
~~
~ w
GB ~c
N S-1 0 SM • ~ -
u w r
0 w ~c .
w > ;J:.D_ ~ ~.
0 (SM) Tan fine silty sand (medium dense. moist)
u z -: GB L
S-2 '
C -
SM
wC
~
--~-8.5
GB
(SP-SM) Tan fine sand with silt (medium dense, moist)
S-3
SP-
_J_Q,Q_ SM
L
: I I , 1.0
No caving observed
No groundwater seepage observed
The depths on the test pit logs are based on an average of measurements across the test pit and should be considered
accurate ta 0.5 foot.
Bottom of test pit at 11.0 feet.
' i
E3RA, Inc. BORING NUMBER TH-1
I I P.O. Box44840 PAGE 1 OF 1 ,E'RA, Inc. Tacoma, WA 98448 Figure A-3
Telephone: 253-537-9400
----' Fax: 253-537-9401
CLIENT E_,:i_com_R._~s Engineering & Surveying PROJECT NAME 3616 Lincoln Ave NE ---
PROJECT NUMBER T15023 PROJECT LOCATION Renton, WashinQ!on
DATE STARTED 3/5/15 COMPLETED 3/5/15 GROUND ELEVATION HOLE SIZE
DRILLING CONTRACTOR DSE GROUND WATER LEVELS:
DRILLING METHOD Steel Tracked Excavator AT TIME OF DRILLING -
LOGGED BY ZLL CHECKED BY JEB AT END OF DRILLING --
NOTES AFTER DRILLING -.
w a_
:c ~ffi ui ,!
f--w"' u :c '-'
a_ "' -" :a; ui a_ 0 MATERIAL DESCRIPTION w-~-" " a.:, ::i ~z '-'
(I)
0
' '1..3_n Landscaping bark
~ ..
0 SM (SM) Dark brown silty sand with copious organics (loose. moist) (Topsoil Horizon)
w
--2.0 Large root complexes encountered at 1 foot ~L --0 ------
I {SM) Tan fine silty sand (medium dense, moist)
sL .
" GB w
" S-1 SM 0
~~
" j a:
" "
~
~
'C u w
" 0 w
0
w > <
3
8 z :a
6.0
No caving observed
No groundwater seepage observed
The depths on the test pit logs are based on an average of measurements across the test pit and should be considered
accurate to 0.5 foot.
Bottom of borehole at 6.0 feet.
APPENDIX B
LABO RA TORY TESTING RES UL TS
Particle Size Analysis Summary Data
Job Name: 3616 Lincoln Ave NE, Renton Geotech
Job Number: T15023
Tested By: CF
Date: 316115
Boring #: TP-1
Sample#: 1
Depth: 3' bgs
!Moisture Content(%) I 24.0%1
Sieve Size Percent Size Fraction Percent By
Passing(%) Weight
3.0 in. 75.0 100.0 Coarse Gravel
1.5 in. 37.5 100.0 Fine Gravel 6.4
314 in. 19.0 100.0
3/8 in. 9.5-mm) 100.0 Coarse Sand 0.4
No. 4 /4.75-mm) 93.6 Medium Sand 2.5
No. 10 /2.00-mm\ 93.2 Fine Sand 60.3
No. 20 (.850-mml 92.2
No. 40 (.425-mm) 90.7 Fines 30.4
No. 60 f.250-mm\ 86.6 Total 100.0
No. 100 (.150-mm) 67.5
No. 200 (.075-mm) 30.4
LL
Pl
D10
D30
D60 0.13
Cc
Cu
ASTM Oassification
[ Group Name Light-brown silty sand
Symbol (SM) (med. dense, moist)
E3RA Figure 8-1
Soil Classification Data Sheet
Sample Distribution
U.S. Standard Sieve Sizes
3" 1.5" 3/4"
-+-Sample Distribution
318'' 4 10 20 40 60 100 200
I I I I I I I I I I I
100 .
·1 ,. l " ' . .
90 . -I.-.--------·
I I\ i ' 80 ! --.
. \ ! !
70 ' ! I \ ~
!
,
! ! !
Cl)
C 60 ' ~-
\
-. -!~ ~--·-
·m ! . .. i I I D. 50 i ---,-! -C ' I .. i
1--
I ! ~ 40 -
'
---..
'1
I D.
30 j I .,
20 I I r
' I I
I
i
I
10
~u-
I iJ I
!
I 'i 0 . -~
1000 100 10 1 0.1 0.01 0.001
Particle Size (mm)
E3RA Sample Distribution Job Name: 3616 Lincoln Ave NE, Renton Ge, Samole #: 1
Job Number: T15023 Date: 3/6/15
Figure: B-2 Tested Bv: CF Deoth: 3' bas
Exoloration #: TP-1
Particle Size Analysis Summary Data
Job Name: 3616 Lincoln Ave NE, Renton Geotech
Job Number: T15023
Tested By: CF
Date: 3/6/15
Boring #: TP-1
Sample#: 3
Depth: 9' bgs
I Moisture Content(%) I 23.6%1
Sieve Size Percent Size Fraction Percent By
Passing(%) Weight
3.0 in. (75.0) 100.0 Coarse Gravel
1.5 in. (37.5) 100.0 Fine Gravel
3/4 in. /19.0) 100.0
3/8 in. /9.5-mml 100.0 Coarse Sand 0.4
No. 4 (4. 75-mml 100.0 Medium Sand 1.1
No. 10 (2.00-mml 99.6 Fine Sand 90.9
No. 20 (.850-mm) 99.2
No. 40 (.425-mm) 98.5 Fines 7.6
No. 60 1.250-mm) 85.0 Total 100.0
No. 100 L 150-mm\ 41.2
No. 200 (.075-mml 7.6
LL
Pl
D10 0.08
D30 0.12
D60 0.19
Cc 0.96
Cu 2.37
A5TM Oassification
r Group Name Light-brown poorly graded sand with silt
Symbol (SP-SM) (med. dense, moist)
--
E3RA Figure B-3
Soil Classification Data Sheet
Sample Distribution
U.S. Standard Sieve Sizes
" " -+-Sample Distribution 3 1.5" 3/4 318" 4 10 20 40 60 100 200
I I I I I I I I I I I
100 I I ·1 [.-~~I~' 1 I j I \I i
90 , I --
I I ,
80 -f--' ----H----++++-+-------
! I !
I I !
ro , -i I I
C) . I
.5 60 i · ---= , I
.. I I I o. 50 --· +-H-+-+-+-+--+----+ -'
; I I I
i:? 40 i 1,~•f----t+--+-+-I
if : I I I I \
30 : I ,
I \ 1 ~· ---1
20 ----
: i
10 I ,
o I [ I! ~ u
1000 100 10 1 0.1 0.01 0.001
Particle Size (mm)
E 3 RA Sample Distribution Job Name: 3616 Lincoln Ave NE, Renton Ge Samele#: 3
Job Number: T15023 Date: 3/6/15
Figure: 8-4 Tested By: CF Depth: 9' bQs
Exploration #: TP-1
SECTION?
OTHER PERMITS
SECTIONS
ESC ANALYSIS AND DESIGN
TESCBMPs
The potential for erosion within the site will be mitigated by use of erosion control measures
during clearing, grading, and site development activities. Filter fences will be installed along the
downhill perimeter of the site to protect adjacent properties from sediment-laden water. A
rocked construction entrance will be installed at the entrance to the site to protect mud from
entering the paved roadway. Stockpiles and exposed disturbed areas will be covered to protect
from erosion and sediment runoff.
SECTION9
BOND QUANTITIES, FACILITY SUMMARIES, AND
DECLARATION OF COVENANT
Bond Quantities
To be determine prior to final engineering approval.
Facility Summaries
Not applicable.
Declaration of Covenant
Not applicable to tbis project.
SECTION 10
OPERATIONS AND MAINTENANCE MANUAL
Operations and Maintenance Instructions Flow Control BMPs
Your property contains a storm water management flow control BMP (best management practice)
called "limited infiltration," which was installed to mitigate the stormwater quantity and quality
impacts of some or all of the impervious surfaces on your property. Limited infiltration is a
method of soaking runoff from impervious area (such as paved areas and roofs) into the ground.
Infiltration devices, such as gravel filled trenches, drywells, and ground surface depressions,
facilitate this process by putting runoff in direct contact with the soil and holding the runoff long
enough to soak most of it into the ground. To be successful, the soil condition around the
infiltration device must be able to soak water into the ground for a reasonable number of years.
The infiltration devices used on your property include the following as indicated on the flow
control BMP site plan: n gravel filled trenches, D drywells. The size, placement, and
composition of these devices as depicted by the flow control BMP site plan and design details
must be maintained and may not be changed without written approval either from the King
County Water and Land Resources Division or through a future development permit from King
County.
Infiltration devices must be inspected annually and after major storm events to identify and
repair any physical defects. Maintenance and operation of the system should focus on ensuring
the system's viability by preventing sediment-laden flows from entering the device. Excessive
sedimentation will result in a plugged or non-functioning facility. If the infiltration device has a
catch basin, sediment accumulation must be removed on a yearly basis or more frequently if
necessary. Prolonged ponding around or atop a device may indicate a plugged facility. If the
device becomes plugged, it must be replaced. Keeping the areas that drain to infiltration devices
well swept and clean will enhance the longevity of these devices. For roofs, frequent cleaning of
gutters will reduce sediment loads to these devices.
Operations and Maintenance for Water Quality BMPs
Water quality design is not required, because the total proposed impervious surfaces for new
project site will be less than 5,000 square feet.
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