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Associated Earth Sciences, Inc.
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Kirkland | Mount Vernon | Tacoma
Subsurface Exploration, Geotechnical Engineering,
and Stormwater Infiltration Feasibility Report
NEW LIFE CHURCH OFFICE BUILDING
Renton, Washington
Prepared For:
RENTON NEW LIFE CHURCH
January 31, 2024
Project No. 20140005E002
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Kirkland | Tacoma | Mount Vernon
425‐827‐7701 | www.aesgeo.com
January 31, 2024
Project No. 20140005E002
Renton New Life Church
15711 152nd Avenue SE
Renton, Washington 98058
Attention: Mr. Cal Carpenter
Subject: Subsurface Exploration, Geotechnical Engineering,
and Stormwater Infiltration Feasibility Report
New Life Church Office Building
15711 152nd Avenue SE
Renton, Washington
Dear Mr. Carpenter:
We are pleased to present the referenced report. This report summarizes the results of our
subsurface exploration, geotechnical engineering, and stormwater infiltration feasibility studies,
and offers recommendations for the design of the project. This report is based on preliminary
architectural, civil, and structural plan sheets; on AESI’s familiarity with subsurface conditions at
the site from our participation in previous projects onsite; and on our discussions with the design
team.
We have enjoyed working with you on this study and are confident that the recommendations
presented in this report will aid in the successful completion of your project. If you should have
any questions, or if we can be of additional help to you, please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Bruce W. Guenzler, L.E.G.
Principal Engineering Geologist
BWG/ld – 20140005E002‐002
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
SUBSURFACE EXPLORATION, GEOTECHNICAL ENGINEERING,
AND STORMWATER INFILTRATION FEASIBILITY REPORT
NEW LIFE CHURCH OFFICE BUILDING
Renton, Washington
Prepared for:
Renton New Life Church
15711 152nd Avenue SE
Renton, Washington 98058
Prepared by:
Associated Earth Sciences, Inc.
911 5th Avenue
Kirkland, Washington 98033
425‐827‐7701
January 31, 2024
Project No. 20140005E002
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Project and Site Conditions
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 1
I. PROJECT AND SITE CONDITIONS
1.0 INTRODUCTION
This report presents the results of our subsurface exploration, geotechnical engineering, and
stormwater infiltration feasibility studies for the proposed new office building at New Life Church
in Renton, Washington. The location of the subject site is shown on the “Vicinity Map,” Figure 1.
The approximate locations of the explorations we relied on to formulate the recommendations
in this report are shown on the “Existing Site and Exploration Plan,” Figure 2. Interpretive
subsurface exploration logs are presented in Appendix A. When project plans have been finalized,
we recommend that the conclusions and recommendations contained in this report be reviewed
and modified, or verified, as necessary.
1.1 Purpose and Scope
The purpose of this study was to provide geotechnical engineering recommendations for design
and construction of the planned new office building using subsurface data from explorations
completed by Associated Earth Sciences, Inc. (AESI) for previous projects onsite. This report
summarizes our fieldwork and offers development recommendations based on our present
understanding of the project.
1.2 Authorization
Our work was completed in accordance with our scope of work letter dated January 22, 2024.
We were authorized to proceed by means of a signed copy of our proposal. This report has been
prepared for the exclusive use of the Renton New Life Church and their agents for specific
application to this project. Within the limitations of scope, schedule, and budget, our services
have been performed in accordance with generally accepted geotechnical engineering and
engineering geology practices in effect in this area at the time our report was prepared. No other
warranty, express or implied, is made.
2.0 PROJECT AND SITE DESCRIPTION
This report was completed with an understanding of the project based on our discussions with
the design team and a review of preliminary civil engineering plan sheets dated April 21, 2023,
preliminary architectural plan sheets dated January 2, 2024, and on undated preliminary
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Project and Site Conditions
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 2
structural engineering sheets. AESI is familiar with the site through our participation in several
previous projects at the existing church in 1998, 2005, 2007, 2014, and 2022.
The project site is the existing New Life Church in Renton, Washington. Current development
includes several existing buildings grouped on the south side of the developed portion of the site,
paved parking areas and a partially‐covered sports court to the north of the building complex,
and grass sports and playfields at the northwest corner of the site. Site improvements also
include a bridge crossing Madson Creek northwest of the building complex, retaining wall
structures to the southwest of the building complex, and a stormwater pond at the northeastern
edge of the parking area. Existing buildings are supported by augercast pile, aggregate pier, and
pin pile foundation systems to mitigate static and seismic settlement risks associated with
relatively weak, saturated, and liquefaction‐susceptible sediments encountered at shallow
depths below the site.
We understand that the current project will include construction of a new 96,664‐square‐foot,
two‐story office building and associated utility work just to the south of the stormwater pond at
the northeast corner of the property. Associated utility work includes the rerouting of the water
main for the site to supply the new building and connecting to the stormwater system.
3.0 SUBSURFACE EXPLORATION
This report relies on subsurface exploration information from our previous studies which includes
three hand‐auger borings, twenty‐three subsurface exploration borings (one completed as a
monitoring well), eighteen exploration pits, and two infiltration test pits completed onsite by
AESI between 1998 and 2022 for design and construction of previous projects onsite. A site‐wide
plan showing all explorations onsite is presented on Figure 2, “Existing Site and Exploration Plan.”
The various types of sediments, as well as the depths where characteristics of the sediments
changed, are indicated on the exploration logs presented in Appendix A. For this report, only logs
of selected explorations applicable to the current study are included in Appendix A. Other
exploration logs are available on request but are not included. The depths indicated on the logs
where conditions changed may represent gradational variations between sediment types in the
field. The locations of our field explorations were determined by approximate measurements
from the known site features shown on the air photograph used as a basis for Figure 2.
The conclusions and recommendations presented in this report are based on the previously
completed explorations onsite in support of earlier projects. The number, locations, and depths
of the explorations were completed within site and budgetary constraints. Because of the nature
of exploratory work below ground, extrapolation of subsurface conditions between field
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Project and Site Conditions
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 3
explorations is necessary. It should be noted that differing subsurface conditions might
sometimes be present due to the random nature of deposition and the alteration of topography
by past grading and/or filling. The nature and extent of any variations between the field
explorations may not become fully evident until construction. If variations are observed at that
time, it may be necessary to re‐evaluate specific recommendations in this report and make
appropriate changes.
4.0 SUBSURFACE CONDITIONS
Subsurface conditions at the project site were inferred from our previous studies at the site,
visual reconnaissance of the site, and review of select applicable geologic literature. The
following sections describe site stratigraphy, regional geology, and observed groundwater.
4.1 Regional Geologic Map and Information by Others
We reviewed a published geologic map of the project area, Geologic Map of the Renton
Quadrangle, King County, Washington, U.S. Geological Survey (USGS), Geologic Quadrangle Map
GQ‐405, scale 1:24,000, by D.R. Mullineaux (1965). The referenced map indicates that the site is
expected to be underlain at shallow depths by alluvium, specifically sand and gravel of the Cedar
River. Our previous on‐site explorations and interpretations are generally consistent with the
conditions depicted on the referenced published map.
4.2 Stratigraphy
Exploration borings near the current project generally encountered approximately 1 to 9 feet of
existing fill, underlain by alluvial sediments, which were in turn underlain by older Vashon or
pre‐Vashon sediments. The following section presents more detailed subsurface information.
Fill
Existing fill sediments (those not naturally deposited) were encountered in some of our previous
explorations. In previously completed subsurface explorations closest to the current project,
observed thickness of existing fill ranged from approximately 1 to 9 feet below existing parking
lot grade. The fill generally consisted of very loose to medium dense, silty, gravelly, fine sand, to
silty, sandy gravel with fragments of concrete, brick, and other construction materials.
Due to its variable density and organic content, existing fill is not suitable for direct structural
support. Assessment and remedial preparation of existing fill should be completed at the time of
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Project and Site Conditions
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 4
construction below all structures that are not pile‐supported. Excavated existing fill material is
expected to be silty and highly moisture‐sensitive, and will be most economically worked during
dry site and weather conditions. Reuse of excavated existing fill in structural fill applications is
only permitted if explicitly allowed by project specifications, if all deleterious materials are
removed, and if the material is at a moisture content that allows compaction to the specified
level for the intended application. Existing fill is not suitable for infiltration.
Holocene Alluvium
Alluvium is interpreted to be present beneath any fill and/or surfacing materials site wide. The
alluvium encountered in our explorations consisted of very loose to loose, moist, silt ranging to
sand with variable silt and variable organic content and coarse sand and gravel. The fine‐grained
silt/sand was generally thinly bedded to bedded (0.5 centimeters [cm] to 30 cm), with moderately
sharp contacts between beds. These soils are interpreted to be overbank deposits that were
deposited on the floodplain of the Cedar River by sporadic flood events since the most recent
glaciation. Shallow groundwater or fine‐grained deposits are limiting factors for infiltration at the
lower elevation portions of the site. The finer‐grained alluvium layer varies from 5.5 to 15 feet in
thickness and in most explorations is underlain by a gravel layer, interpreted to be Holocene‐age
sand and gravel from the Cedar River.
In earlier phases of our work, loose to medium dense gravel or sandy gravel was encountered
beneath the finer‐grained alluvium soils in the north portion of the site. We interpret this to be
sand and gravel from the Cedar River, deposited within or near the main river channel. Where
encountered, this layer was typically saturated and displayed moderate to heavy groundwater
seepage.
Due to its variable density and potential susceptibility to liquefaction during a seismic event,
Holocene alluvium is not suitable for direct structural support. Due to its increased fines content
at this site, Holocene alluvium is not suitable for stormwater infiltration.
Vashon or Pre‐Vashon Undifferentiated Sediments
Below the Holocene alluvium, our deeper exploration borings encountered dense to very dense,
moist, silty sand with gravel. This material was interpreted to be an older Vashon or
pre‐Vashon‐age deposit that has been glacially consolidated. This material was encountered in
our exploration borings, EB‐1 through EB‐3 and EB‐7 below approximately 30 feet, as well as in
EB‐4 though EB‐6, EB‐8, and EB‐12 through EB‐20 below approximately 15 feet. Our remaining
exploration borings near the current project terminated in the Holocene alluvium.
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Project and Site Conditions
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 5
4.3 Hydrology
During our previous studies, groundwater was observed in most of the exploration locations at
depths varying from approximately 4.5 to 14 feet below the ground surface at the time of
exploration, and is interpreted to represent a shallow water table aquifer. Seepage from
exploration pit sidewalls in the northwest portion of the site was moderate to heavy, and typically
originated from sand or gravel beds within or underlying the siltier alluvium.
A monitoring well was installed in 2014 near the northwest corner of the site; groundwater levels
were monitored for 5 months through one winter season and we observed a seasonal high
groundwater level of approximately 2 feet below ground surface which corresponds to an
elevation of approximately 102 feet.
At the time of our most recent explorations, in August 2022, we observed moderate flows in
Madson Creek, along Maple Valley Highway, at approximately 2 feet below the bank full elevation
of approximately 104 feet. Additionally, we observed that the area surrounding the portion of
Madson Creek which generally runs south to north through the middle of the property was
previously delineated as wetland and wetland vegetation was present.
Ground surface elevations mentioned here and shown on the exploration logs are approximate
and are based on Light Detection and Ranging (LiDAR)‐based topographic maps generated from
the Washington State Plane North Coordinate System FIPS 4601, in the NAD83(HARN)/NAV88
datum. Therefore, groundwater level elevations are also estimates.
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Geologic Hazards and Mitigations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 6
II. GEOLOGIC HAZARDS AND MITIGATIONS
The following discussion of potential geologic hazards is based on the geologic conditions as
observed and discussed herein.
5.0 SLOPE STABILITY HAZARDS AND MITIGATIONS
The Renton Municipal Code (RMC 4.3.050.G.5) defines regulated Steep Slopes as:
“i. Sensitive Slopes: A hillside, or portion thereof, characterized by: (a) an average slope of twenty
five percent (25%) to less than forty percent (40%) as identified in the City of Renton Steep
Slope Atlas or in a method approved by the City; or (b) an average slope of forty percent (40%)
or greater with a vertical rise of less than fifteen feet (15') as identified in the City of Renton
Steep Slope Atlas or in a method approved by the City; (c) abutting an average slope of twenty
five percent (25%) to forty percent (40%) as identified in the City of Renton Steep Slope Atlas
or in a method approved by the City. This definition excludes engineered retaining walls.
ii. Protected Slopes: A hillside, or portion thereof, characterized by an average slope of forty
percent (40%) or greater grade and having a minimum vertical rise of fifteen feet (15') as
identified in the City of Renton Steep Slope Atlas or in a method approved by the City.”
Based on the City of Renton Steep Slope Atlas, the portion of the site to the south of the existing
building complex is classified as a Protected Steep Slope.
The currently proposed new office building, as well as utility work along Maple Valley Highway
are distant from the Protected Steep Slope, with other existing buildings between the slope and
the proposed project. No detailed quantitative assessment of site slopes was completed as part
of this study, and none is warranted, in our opinion.
6.0 SEISMIC HAZARDS AND MITIGATIONS
The following discussion is a general assessment of seismic hazards that is intended to be useful
to the project design team in terms of understanding seismic issues, and to the structural
engineer for design.
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Geologic Hazards and Mitigations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 7
All of Western Washington is at risk of strong seismic events resulting from movement of the
tectonic plates associated with the Cascadia Subduction Zone (CSZ), where the offshore Juan de
Fuca plate subducts beneath the continental North American plate. The site lies within a zone of
strong potential shaking from subduction zone earthquakes associated with the CSZ. The CSZ can
produce earthquakes up to magnitude 9.0, and the recurrence interval is estimated to be on the
order of 500 years. Geologists infer the most recent subduction zone earthquake occurred in
1700 (Goldfinger et al., 2012). Three main types of earthquakes are typically associated with
subduction zone environments: crustal, intraplate, and interplate earthquakes. Seismic records
in the Puget Sound region document a distinct zone of shallow crustal seismicity (e.g., the Seattle
Fault Zone). These shallow fault zones may include surficial expressions of previous seismic
events, such as fault scarps, displaced shorelines, and shallow bedrock exposures. The shallow
fault zones typically extend from the surface to depths ranging from 16 to 19 miles. A deeper
zone of seismicity is associated with the subducting Juan de Fuca plate. Subduction zone seismic
events produce intraplate earthquakes at depths ranging from 25 to 45 miles beneath the Puget
Lowland including the 1949, 7.2‐magnitude event; the 1965, 6.5‐magnitude event; and the 2001,
6.8‐magnitude event and interplate earthquakes at shallow depths near the Washington coast
including the 1700 earthquake, which had a magnitude of approximately 9.0. The 1949
earthquake appears to have been the largest in this region during recorded history and was
centered in the Olympia area. Evaluation of earthquake return rates indicates that an earthquake
of the magnitude between 5.5 and 6.0 is likely within a given 20‐year period.
Generally, there are four types of potential geologic hazards associated with large seismic events:
1) surficial ground rupture, 2) seismically induced landslides or lateral spreading, 3) liquefaction,
and 4) ground motion. The potential for each of these hazards to adversely impact the proposed
project is discussed below.
6.1 Surficial Ground Rupture
Generally, the largest earthquakes that have occurred in the Puget Sound area are sub‐crustal
events with epicenters ranging from 25 to 45 miles in depth. Earthquakes that are generated at
such depths usually do not result in fault rupture at the ground surface. Current research
indicates that surficial ground rupture is possible in areas close to the Tacoma Fault Zone and
Seattle Fault Zone, the closest mapped faults to the project site. Our current understanding of
these fault zones is limited, and it is an active area of research. We reviewed the USGS Interactive
Fault Map web application (https://www.usgs.gov/tools/interactive‐us‐fault‐map, January
2024). The nearest trace of the Seattle Fault Zone is mapped about 2.75 miles northeast of the
site and the nearest trace of the Tacoma Fault Zone is about 11.5 miles southwest of the site.
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Geologic Hazards and Mitigations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 8
Due to the distance from the site to mapped faults, damage to the proposed project as a result
of surface rupture during a seismic event is low, in our opinion.
6.2 Seismically Induced Landslides
When the existing buildings were constructed a quantitative slope stability assessment was
completed for steep slopes adjacent to the south. The existing buildings were provided with a
setback from the steep slope, and a catchment wall to intercept slope debris that may be
generated from shallow surficial landslides. The currently proposed project is in an area distant
from the existing steep slopes. A detailed seismic slope assessment was not completed for the
new building that is currently proposed and none is warranted, in our opinion.
6.3 Liquefaction
Liquefaction is a process through which unconsolidated soil loses strength as a result of
vibrations, such as those which occur during a seismic event. During normal conditions, the
weight of the soil is supported by both grain‐to‐grain contacts and by the fluid pressure within
the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the
grain‐to‐grain contact, increase the pore pressure, and result in a temporary decrease in soil
shear strength. The soil is said to be liquefied when nearly all of the weight of the soil is supported
by pore water pressure alone. Liquefaction can result in deformation of the sediment and
settlement of overlying structures. Areas most susceptible to liquefaction include those areas
underlain by non‐cohesive silt and sand with low relative densities, accompanied by a shallow
water table.
Our previous explorations encountered loose to medium dense, granular alluvial sediments in
the current project area. The nearest exploration borings (EB‐9 to EB‐14) were completed during
July and August 2005. At the time of drilling the alluvial sediments were not observed to be
saturated, and therefore would not be potentially susceptible to liquefaction during a seismic
event. However previous observations onsite indicate that seasonally shallower groundwater is
likely.
We completed a limited liquefaction analysis for the current project using the computer program
Liquefy Pro by Civiltech Software. The analysis was limited in that the 2005 exploration data did
not include laboratory grain‐size analyses, which are one of the inputs for liquefaction analyses.
We also modeled the loose alluvial sediments as saturated, though the alluvial sediments were
not observed to be saturated at the time of exploration. Nevertheless for the sake of estimating
the possible range of liquefaction‐induced settlement that could occur during a design‐level
seismic event we used stratigraphic and Standard Penetration Test (SPT) blow count data from
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Geologic Hazards and Mitigations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 9
EB‐12, estimated soil grain‐size distributions based on visual soil descriptions from EB‐12, and an
estimated depth to groundwater of 4 feet below existing parking lot grade. Under these
conditions the predicted settlement during a design‐level seismic event ranges from
approximately 4 to 9 inches. This settlement estimate should be considered approximate due to
the need to estimate inputs for the analysis, however it does provide a useful benchmark. The
pin piles recommended in this report are expected to be an effective mitigation to limit structural
settlement associated with a design‐level seismic event. It should be noted that any structures
that are not pile‐supported, potentially including the first level slab‐on‐grade floor, could
experience settlement and settlement‐related deformation as a result of liquefaction during an
earthquake.
6.4 Ground Motion/Seismic Site Class (2018 International Building Code)
It is our opinion that earthquake damage to the proposed structure when founded on suitable
bearing strata in accordance with the recommendations contained herein, will likely be caused by
the intensity and acceleration associated with the event. Structural design of the structure should
follow 2018 International Building Code (IBC) standards using Site Class “F” as defined in
Table 20.3‐1 of American Society of Civil Engineers (ASCE) 7‐16 Minimum Design Loads and
Associated Criteria for Buildings and Other Structures. It may be possible to design the new
building in accordance with Site Class “E” if the fundamental period of the new building is less
than 0.5 seconds, in accordance with provisions in ASCE 7‐16. We are available on request to
work with the project structural engineer on seismic design aspects of the new building.
7.0 EROSION HAZARDS AND MITIGATIONS
Sitework around the new building is expected to be minimal as there are no planned grade
changes. Sitework associated with utility work onsite and at the Maple Valley Highway frontage
will be limited to what is needed to install new buried utilities and reroute the existing water
main. All areas disturbed by construction should follow Temporary Erosion and Sedimentation
Control (TESC) procedures per City of Renton standards.
To mitigate the construction site erosion potential, project plans should include implementation
of temporary erosion controls in accordance with local standards of practice. Ultimately, the
success of the TESC plan depends on a proactive approach to project planning and contractor
implementation and maintenance. We recommend the following Best Management Practices
(BMPs) to mitigate erosion hazards and potential for off‐site sediment transport:
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Geologic Hazards and Mitigations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 10
1. Construction activity should be scheduled or phased as much as possible to avoid
earthwork activity during the wet season.
2. The winter performance of a site is dependent on a well‐conceived plan for control of site
erosion and stormwater runoff. The site plan should include ground‐cover measures and
staging areas. The contractor should be prepared to implement and maintain the required
measures to reduce the amount of exposed ground.
3. TESC elements and perimeter flow control should be established prior to the start of
demolition or grading.
4. During the wetter months of the year, or when significant storm events are predicted
during the summer months, the work area should be stabilized so that if showers occur,
it can receive the rainfall without excessive erosion or sediment transport. The required
measures for an area to be “buttoned‐up” will depend on the time of year and the
duration that the area will be left unworked. During the winter months, areas that are to
be left unworked for more than 2 days should be mulched or covered with plastic. During
the summer months, stabilization will usually consist of seal‐rolling the subgrade. Such
measures will aid in the contractor’s ability to get back into a work area after a storm
event. The stabilization process also includes establishing temporary stormwater
conveyance channels through work areas to route runoff to the approved treatment/
discharge facilities.
5. All disturbed areas should be revegetated as soon as possible. If it is outside of the
growing season, the disturbed areas should be covered with mulch. Straw mulch provides
a cost‐effective cover measure and can be made wind‐resistant with the application of a
tackifier after it is placed.
6. Surface runoff and discharge should be controlled during and following development.
Uncontrolled discharge may promote erosion and sediment transport.
7. Soils that are to be reused around the site should be stored in such a manner as to reduce
erosion from the stockpile. Protective measures may include, but are not limited to,
covering stockpiles with plastic sheeting, or the use of silt fences around pile perimeters.
It is our opinion that with the proper implementation of the TESC plan and by field‐adjusting
appropriate erosion mitigation (BMPs) throughout construction, the potential adverse impacts
from erosion hazards on the project may be mitigated.
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geotechnical Engineering,
New Life Church Office Building and Stormwater Infiltration Feasibility Report
Renton, Washington Design Recommendations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 11
III. DESIGN RECOMMENDATIONS
8.0 INTRODUCTION
Our explorations indicate that, from a geotechnical engineering standpoint, the proposed project
is feasible provided the recommendations in this report are incorporated into design and
construction.
The bearing stratum was observed to be covered by loose existing fill and alluvial sediments
ranging up to 34 feet in depth below the existing ground surface. Existing fill and loose native
sediments encountered in our explorations are not suitable for foundation support and warrant
assessment and possible remedial preparation below pavements and other shallow structures
that are not pile‐supported. This report assumes new structural loads for the new building will
be supported by driven pin piles that derive bearing from dense soils below loose fill and alluvial
sediments.
This report provides recommendations for remedial preparation of existing fill and alluvial
sediments below the new building while leaving some of those existing unremediated weak
materials in place below the new floor slab. Relying on existing weak sediments below a floor
slab that is not pile‐supported carries some risk of post‐construction static and seismically
induced settlement, and also offers substantial construction cost savings as compared to
providing pin pile support for floor slabs. If the risk of future floor slab settlement is not
acceptable, new floor slabs should be supported on pin piles.
Stormwater infiltration is not recommended at the site due to shallow groundwater and soils
with a significant fine‐grained component. Stormwater infiltration feasibility is discussed in detail
in Section 15.0.
9.0 SITE PREPARATION
Prior to site work, erosion and surface water control should be established around the perimeter
of work areas in accordance with City of Renton requirements.
9.1 Clearing and Stripping
Existing structures, pavement, buried utilities, vegetation, topsoil, and any other deleterious
materials should be removed where they are located below planned construction areas. We
estimate the stripping depth to generally be 6 inches to 1 foot. Any disturbed soils or depressions,
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Subsurface Exploration, Geologic Hazards, and
New Life Church Office Building Addition Geotechnical Engineering Report
Renton, Washington Design Recommendations
January 31, 2024 ASSOCIATED EARTH SCIENCES, INC.
KAM/ld ‐ 20140005E001‐002 Page 12
such as those that may be caused by demolition activities, below planned final grades should be
compacted with a smooth‐drum, vibratory roller to at least 90 percent of the modified Proctor
maximum dry density, as determined by the ASTM International (ASTM) D‐1557 test procedure,
and to a firm and unyielding surface, then structural fill should be placed to reach planned grades
as discussed under the “Structural Fill” section of this report.
Where existing fill and natural sediments are relatively free of demolition debris and organics
and near their optimum moisture content for compaction, they can be segregated and
considered for reuse as structural fill if allowed by project specifications. Portions of the native
sediments encountered in our explorations contained significant silt fractions and are moisture‐
sensitive; these may be difficult to reuse as structural fill.
9.2 Assessment and Remedial Preparation
Once clearing, stripping, and excavation to planned grade have been completed, structural areas
should be visually assessed and proof‐rolled under the observation of the geotechnical engineer.
Any soft, yielding, excessively organic, or otherwise unsuitable materials warrant remedial action
that should be determined onsite during construction when field conditions are known.
Building Pad Subgrades
The building pad should be prepared by overexcavating 2 feet below the planned base of capillary
break elevation, proof‐rolling and compacting the subgrade, repairing any areas that are yielding,
organic, or otherwise unsuitable for structural support, and placing 2 feet of crushed rock or
crushed concrete fill to act as a working surface. The new structural fill will also provide support
for slab‐on‐grade floors where pin piles are not planned. The risk of potential future floor slab
settlement that results from leaving existing fill and alluvial sediments in place below a floor slab
that is not pile‐supported is discussed further in Section 8.0 above and Section 12.0 below.
Paving and Sidewalk Subgrades
Subgrades for sidewalks, courtyards, asphalt paving, and similar structures should be exposed,
visually assessed, and proof‐rolled. Any soft, yielding, excessively organic or otherwise unsuitable
areas should receive remedial preparation tailored to conditions at the time the work is
completed.
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9.3 Temporary Cut Slopes
In our opinion, stable construction slopes should be the responsibility of the contractor and
should be determined during construction based on the conditions encountered at that time. For
estimating purposes, however, we recommend that temporary, unsupported cut slopes within
unsaturated fill soils or alluvial sediments should be planned at a maximum slope of 1.5H:1V
(Horizontal:Vertical). Temporary cuts into saturated sediments below the groundwater table
should not be attempted.
Temporary cut slopes may need to be adjusted in the field at the time of construction based on
the presence of surface water or perched seepage zones. Groundwater seepage may require
temporary dewatering in the form of pumped sumps or other measures. As is typical with
earthwork operations, some sloughing and raveling may occur, and cut slopes may have to be
adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times.
If steeper or deeper cuts are required, then temporary shoring may be necessary.
9.4 Drainage
Significant groundwater was observed at the time of our previous explorations. Depending upon
the time of year that construction is performed, seepage may be encountered in excavations.
Therefore, prior to site work and construction, the contractor should be prepared to provide
temporary drainage and subgrade protection, as necessary.
9.5 Site Disturbance
The existing fill soils and native sediments contain a significant percentage of fine‐grained
material, which makes them moisture‐sensitive and subject to disturbance when wet. The
contractor must use care during site preparation and excavation operations so that the
underlying soils are not softened, particularly during wet weather conditions. Because of the
moisture‐sensitive nature of the soils, we anticipate that wet weather construction would
significantly increase the earthwork costs over dry weather construction.
9.6 Winter Construction
The existing fill material and portions of the native soils contain substantial silt and are considered
highly moisture‐sensitive. Soils excavated onsite will likely require drying during favorable dry
weather conditions to allow their reuse in structural fill applications. Care should be taken to seal
all earthwork areas during mass grading at the end of each workday by grading all surfaces to
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drain and sealing them with a smooth‐drum roller. Stockpiled soils that will be reused in
structural fill applications should be covered whenever rain is possible.
If winter construction is expected, crushed rock fill should be used to provide construction staging
areas where exposed soil is present. The stripped subgrade should be observed by
the geotechnical engineer, and should then be covered with a geotextile fabric, such as
Mirafi 500X or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer
at least 10 inches thick in areas where construction equipment will be used.
9.7 Frozen Subgrades
If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to
thaw, and then be recompacted prior to placing subsequent lifts of structural fill. Alternatively,
the frozen material could be stripped from the subgrade to reveal unfrozen soil prior to placing
subsequent lifts of fill. The frozen soil should not be reused as structural fill until allowed to thaw
and adjusted to the proper moisture content, which may not be possible during winter months.
10.0 STRUCTURAL FILL
Structural fill should be placed and compacted according to the recommendations presented in
this section and requirements included in project specifications. Fill material selection, fill
placement, and compaction should be completed in accordance with City of Renton standards
for work in the right‐of‐way. All references to structural fill in this report refer to subgrade
preparation, fill type, placement, and compaction of materials, as discussed in this section. If a
percentage of compaction is specified under another section of this report, the value given in
that section should be used.
10.1 Subgrade Compaction
After overexcavation/stripping has been performed to the satisfaction of the geotechnical
engineer or engineering geologist, the upper 12 inches of exposed ground should be
recompacted to a firm and unyielding condition. If the subgrade contains too much moisture,
suitable recompaction may be difficult or impossible to attain and should probably not be
attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed rock
or quarry spalls to act as a capillary break between the new fill and the wet subgrade. Where the
exposed ground remains soft and further overexcavation is impractical, placement of an
engineering stabilization fabric may be necessary to prevent contamination of the free‐draining
layer by silt migration from below. After recompaction of the exposed ground is tested and
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approved, or a free‐draining rock course is laid, structural fill may be placed to attain desired
grades.
10.2 Structural Fill Compaction
Structural fill is defined as non‐organic soil, acceptable to the geotechnical engineer, placed in
maximum 8‐inch loose lifts, with each lift being compacted to at least 95 percent of the modified
Proctor maximum dry density using ASTM D‐1557 as the standard. The top of the compacted fill
should extend horizontally a minimum distance of 3 feet beyond footings before sloping down at
an angle no steeper than 2H:1V. Fill slopes should either be overbuilt and trimmed back to final
grade or surface‐compacted to the specified density. In the case of roadway and utility trench
filling, the backfill should be placed and compacted in accordance with City of Renton standards.
10.3 Moisture‐Sensitive Fill
Soils in which the amount of fine‐grained material (smaller than the No. 200 sieve) is greater than
approximately 5 percent (measured on the minus No. 4 sieve size) should be considered
moisture‐sensitive. Use of moisture‐sensitive soil in structural fills is not recommended during
the winter months or under wet site and weather conditions. Most of the on‐site soils are
moisture‐sensitive and have natural moisture contents over optimum for compaction and will
likely require moisture‐conditioning before use as structural fill. If, at the time of construction,
the moisture content of the on‐site soil remains above the optimum level to achieve suitable
compaction, it should be moisture‐conditioned prior to use as structural fill. This could be
achieved by either adding water if the soil is too dry, or aerating the soil during periods of warm,
dry weather if the soil is too wet.
Construction equipment traversing the site when the silty fill and natural sediments are very
moist or wet can cause considerable disturbance. If fill is placed during wet weather or if proper
compaction of the on‐site soil cannot be attained, a select import material consisting of a clean,
free‐draining gravel and/or sand should be used. Free‐draining fill consists of non‐organic soil
with the amount of fine‐grained material limited to 5 percent by weight when measured on the
minus No. 4 sieve fraction and at least 30 percent retained on the No. 4 sieve. City of Seattle
Mineral Aggregate Type 17 (City of Seattle Standard Specifications for Road, Bridge, and
Municipal Construction, 2023 Edition 9‐03.14) is one example of a suitable import aggregate
specification.
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10.4 Structural Fill Testing
The contractor should note that any proposed fill soils must be evaluated by AESI prior to their
use in fills. This would involve providing us with a sample of the material at least 3 business days
in advance to perform a Proctor test to determine its field compaction standard.
A representative from our firm should observe the subgrades and be present during placement
of structural fill to observe and document the work and perform a representative number of
in‐place density tests. In this way, the adequacy of the earthwork may be evaluated as filling
progresses and any problem areas may be corrected at that time. It is important to understand
that taking random compaction tests on a part‐time basis will not assure uniformity or acceptable
performance of a fill. As such, we are available to aid the owner in developing a suitable
monitoring and testing frequency. Such testing and observation may be required by the
governing municipality.
11.0 FOUNDATIONS
The suitable bearing stratum below the location of the proposed building is mantled by a layer
of variable thicknesses of very loose to medium dense undocumented fill and native alluvial
deposits. The existing fill and alluvial sediments are up to approximately 34 feet deep and are
potentially susceptible to static settlement as well as liquefaction‐related settlement during a
seismic event. Subsurface conditions warrant the use of settlement mitigation strategies. At the
time this report was written, the owner and design team elected to include driven pin piles for
support of new structural loads associated with the proposed new building.
11.1 Pin Piles
Pin piles should be installed by a local contractor with demonstrated expertise in pin pile
installations. For planning purposes we recommend designing with 3‐inch‐diameter driven pin
piles with an allowable axial compressive capacity of 6 tons. Pin piles should not be relied on for
lateral or uplift loading. We recommend that we be allowed to agree on mutually acceptable
driving resistance criteria with the pile contractor selected for the project, and that the agreed‐on
driving criteria be verified by at least one load test. Load testing of pin piles may be required by
the City as a condition of permitting. The test may be completed on a production pile or on a pile
installed only for testing provided that materials and procedures are the same for both. Load
testing should be done in axial compression and in accordance with current codes and
requirements.
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The structural engineer should provide pile spacing, locations, splicing details, foundation
connection details, and any other structural design recommendations that are needed.
Pin pile materials and equipment capable of achieving the needed compressive capacity are not
standardized. Different contractors will have different pipe materials, different driving
equipment, and different driving refusal criteria to meet the design capacity. We should be
allowed to review the specific materials and procedures the contractor proposes to use before
they mobilize onsite.
In general, pin piles are installed with an air or hydraulic impact hammer until the specified
refusal criteria are met. Pile lengths are difficult to estimate in advance. During previous pin pile
installations onsite, driving depths ranged from approximately 20 to 45 feet, with most piles
reaching depths of approximately 40 feet. If multiple pipe sections are required, the pipes should
be joined with an extension pin inside the pipe, and/or a sleeve on the outside. If uplift loads are
expected to be placed on the piles at any time, the connections should also be securely welded
to prevent pipe separation at joints.
We recommend that we be allowed to observe the installation of pin piles. We would observe
materials, equipment, and procedures, and confirm refusal for each pile. We recommend that
we be allowed to observe pin pile installation full time to verify installation methods, driving
resistance, load testing, embedment depths, and other aspects of the project. The purpose of
our observations is to confirm that the conditions observed in our explorations and assumed in
preparation of our recommendations are consistent with those encountered at the time of
construction, and to confirm that the materials, procedures, and refusal criteria are consistent
with those we assumed while formulating our recommendations contained in this report.
12.0 FLOOR SUPPORT
Two alternatives are available for support of slab‐on‐grade floors. Supporting floor slabs with pin
piles will increase the number of pin piles and increase pin piles system costs, but will provide
tighter control of future floor slab settlement potential. If some risk of future floor slab
settlement can be tolerated, the upper 2 feet of soils below the floor slab could consist of crushed
rock fill compacted to at least 95 percent of ASTM D‐1557 as recommended in the
“Site Preparation” section of this report. The approach of leaving existing fill in place capped by
2 feet of crushed rock fill below floor slabs may result in larger than typical post‐construction
settlements at a substantial cost savings as compared to providing pin piles for improvement of
soils below new floors. We are available to answer questions related to alternative floor support
options on request.
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Regardless of support method, the floor slab should be cast atop a minimum of 4 inches of
washed pea gravel or washed crushed rock to act as a capillary break where moisture migration
through the slabs is to be controlled. The capillary break material should be overlain by a
10‐mil‐thick vapor barrier material prior to concrete placement.
13.0 PAVEMENT AND SIDEWALK RECOMMENDATIONS
The pavement sections included in this report section are for asphalt cement concrete driveway
and parking areas onsite, and are not applicable to public streets.
On‐site pavement and sidewalk areas should be prepared in accordance with the “Site
Preparation” section of this report. If the stripped native soil or existing fill pavement subgrade
can be compacted to 95 percent of ASTM D‐1557 and is firm and unyielding, no additional
overexcavation is required. Soft or yielding areas should be overexcavated to provide a suitable
subgrade and backfilled with structural fill.
New paving may include areas subject only to light traffic loads from passenger vehicles driving
and parking, and may also include areas subject to heavier loading from vehicles that may include
buses, fire trucks, food service trucks, and garbage trucks. In light traffic areas, we recommend a
pavement section consisting of 3 inches of hot‐mix asphalt (HMA) underlain by 4 inches of
crushed surfacing base course. In heavy traffic areas, a minimum pavement section consisting of
4 inches of HMA underlain by 2 inches of crushed surfacing top course and 4 inches of crushed
surfacing base course is recommended. The crushed rock will provide improved and consistent
drainage, which will extend the service life of paved areas. The crushed rock courses must be
compacted to 95 percent of the maximum density, as determined by ASTM D‐1557. All paving
materials should meet gradation criteria contained in the current Washington State Department
of Transportation (WSDOT) Standard Specifications.
14.0 DRAINAGE CONSIDERATIONS
The sediments underlying the site contain significant amounts of silt and are considered to be
highly moisture‐sensitive. Traffic from vehicles and construction equipment across these
sediments when they are very moist or wet will result in disturbance of the otherwise firm
stratum and result in increased cost. Therefore, prior to site work and construction, the
contractor should be prepared to provide drainage and subgrade protection, as necessary.
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14.1 Foundation Drains
All perimeter footings should be provided with a drain at the footing or subgrade elevation.
Drains should consist of rigid, perforated, PVC pipe surrounded by washed gravel. The level of
the perforations in the pipe should be set at the bottom of the footing, and the perforations
should be located on the lower portion of the pipe. The drains should be constructed with
sufficient gradient to allow gravity discharge away from the structures.
Roof and surface runoff should not discharge into the footing drain system but should be handled
by a separate drain. No drainage should be permitted to discharge on or near slopes.
14.2 Roof and Runoff Drains
Exterior grades adjacent to walls should be sloped downward away from these structures to
achieve surface drainage. Final exterior grades should promote free and positive drainage away
from the building at all times. Water must not be allowed to pond or to collect adjacent to the
foundation or within the immediate building area. It is recommended that a gradient of at least
3 percent for a minimum distance of 10 feet from the building perimeter be provided, except in
paved locations. In paved locations, a minimum gradient of 1 percent should be provided unless
provisions are included for collection and disposal of surface water adjacent to the structures.
Runoff water from impervious surfaces should be collected by a rigid storm drain system that
discharges into the site stormwater system. To minimize erosion, stormwater discharge or
concentrated runoff should not be allowed to flow down any steep slopes.
14.3 Dewatering Considerations
Due to the presence of groundwater within our explorations, we anticipate that some dewatering
will be required during construction, especially in areas of deeper excavations such as utility
trenches. The contractor should be prepared to provide drainage and subgrade protection, as
necessary.
15.0 SHALLOW INFILTRATION FEASIBILITY
In our opinion, based on data included in this report including site reconnaissance, research of
design documents from previous projects onsite, subsurface exploration, and geologic
interpretations, the existing fill soils underlying and adjacent to the proposed improvements are
not a suitable receptor horizon for stormwater infiltration based on random grain size and debris.
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Other limitations on infiltration include shallow depth to groundwater. Our previous explorations
on portions of the site farther from the frontage to Maple Valley Highway encountered native
alluvial sediments at relatively shallow depths that were observed to be seasonally saturated at
near‐surface elevations and wetland conditions exist in portions of the site bordering Madson
Creek. We did not encounter any groundwater in our more recent explorations; however, at the
time of these explorations (August 18, 2022) groundwater was actively flowing in Madson Creek
adjacent to the frontage to Maple Valley Highway, at an elevation approximately 5 feet below
the ground surface elevation of our explorations. Our recent explorations were completed at a
time of year when groundwater elevations are expected to be near their lowest seasonal
elevations.
Due to the observed shallow groundwater conditions and existing fill, shallow infiltration is not
feasible, in our opinion, using conventional shallow infiltration strategies such as infiltration
trenches, infiltrating bioretention areas, or permeable pavements. Full or basic dispersion
stormwater BMPs as well as the use of soil amendments for post‐construction soil quality and
depth mitigation are, in our opinion, feasible from a geotechnical standpoint.
16.0 PROJECT DESIGN AND CONSTRUCTION MONITORING
We are available to provide additional geotechnical consultation as the project design develops
and possibly changes from that which this report is based. In this way, our earthwork and
foundation recommendations may be properly interpreted and implemented in the design. The
City may require a plan review by the geotechnical engineer as a condition of permitting.
The City may also require geotechnical special inspections during construction and preparation
of a final summary letter when construction is complete. We are available to provide
geotechnical engineering and monitoring services during construction. The integrity of the
earthwork and foundations, including pin piles, depends on proper site preparation and
construction procedures. In addition, engineering decisions may have to be made in the field in
the event that variations in subsurface conditions become apparent. Construction monitoring
services are not part of this current scope of work. If these services are desired, please let us
know, and we will prepare a cost proposal for the additional scope.
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17.0 CLOSURE
We have enjoyed working with you on this study and are confident these recommendations will
aid in the successful completion of your project. If you should have any questions or require
further assistance, please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Kristen A. Marohl, L.G.
Senior Staff Geologist
______________________________
Bruce W. Guenzler, L.E.G. Kurt D. Merriman, P.E.
Principal Engineering Geologist Senior Principal Engineer
Attachments: Figure 1: Vicinity Map
Figure 2: Existing Site and Exploration Plan
Appendix A: Exploration Logs
Kurt D.
Merriman, P.E.
Digitally signed by
Kurt D. Merriman, P.E.
Date: 2024.01.31
16:17:23 -08'00'
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
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COUNTY LOCALE LOCATION
PROJECT NO.DATE FIGURE
11/2420140005E002
RENTON NEW LIFE CHURCH
RENTON, WASHINGTON
VICINITY MAP
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PROJECT NO.DATE FIGURE
±
21/2420140005E002
RENTON NEW LIFE CHURCH
RENTON, WASHINGTON
EXISTING SITE AND
EXPLORATION PLAN
DATA SOURCES/REFERENCES:
KING COUNTY: ROADS (5/23), TRAILS (9/22), STREAMS (9/21),
PARCELS (4/23), CITY BOUNDARY (5/23).
EAGLEVIEW TECHNOLOGIES, INC.: AERIAL IMAGERY (2021).
WA DNR LIDAR: KING_COUNTY_WEST_2021, ACQUIRED 4/21, 1.5'
CELL SIZE. CONTOURS DERIVED FROM LIDAR.
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EP-18
HB-1HB-2HB-3
LEGEND
SITE
!(HAND BORING, 2022
MONITORING WELL, 2014
")EXPLORATION PIT, 2014
%,INFILTRATION TEST, 2014
!(EXPLORATION BORING, 2007
!(EXPLORATION BORING, 2005
!(EXPLORATION BORING, 1998
PROPOSED OFFICE BUILDING FOOTPRINT
TRAIL
PARCEL
CITY BOUNDARY
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
APPENDIX A
Exploration Logs
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
Classifications of soils in this report are based on visual field and/or laboratory observations,
which include density/consistency, moisture condition, grain size, and plasticity estimates
and should not be construed to imply field or laboratory testing unless presented herein.
Visual-manual and/or laboratory classification methods of ASTM D-2487 and D-2488 were
used as an identification guide for the Unified Soil Classification System.
OH
PT
CH
OL
MH
CL
ML
SM
SC
GW
SP
GC
SW
GM
GP
Well-graded gravel
and gravel with sand,
little to no fines
Poorly-graded gravel
and gravel with sand,
little to no fines
Clayey gravel
and clayey gravel
with sand
Silty gravel and silty
gravel with sand
Well-graded sand
and sand with gravel,
little to no fines
Poorly-graded sand
and sand with gravel,
little to no fines
Clayey sand and
clayey sand with
gravel
Organic clay or silt
of low plasticity
Organic clay or silt of
medium to high
plasticity
Peat, muck and other
highly organic soils
Silty sand and
silty sand with
gravel
Silt, sandy silt, gravelly
silt, silt with sand or
gravel
Clay of low to medium
plasticity; silty, sandy, or
gravelly clay, lean clay
Elastic silt, clayey silt,
silt with micaceous
or diatomaceous fine
sand or silt
Clay of high
plasticity, sandy or
gravelly clay, fat clay
with sand or gravel
(1
)
Hi
g
h
l
y
Or
g
a
n
i
c
So
i
l
s
Fi
n
e
-
G
r
a
i
n
e
d
S
o
i
l
s
-
5
0
%
o
r
M
o
r
e
P
a
s
s
e
s
N
o
.
2
0
0
S
i
e
v
e
(1
)
Co
a
r
s
e
-
G
r
a
i
n
e
d
S
o
i
l
s
-
M
o
r
e
t
h
a
n
5
0
%
R
e
t
a
i
n
e
d
o
n
N
o
.
2
0
0
S
i
e
v
e
Gr
a
v
e
l
s
-
M
o
r
e
t
h
a
n
5
0
%
o
f
C
o
a
r
s
e
F
r
a
c
t
i
o
n
Re
t
a
i
n
e
d
o
n
N
o
.
4
S
i
e
v
e
12
%
F
i
n
e
s
5%
F
i
n
e
s
Sa
n
d
s
-
5
0
%
o
r
M
o
r
e
o
f
C
o
a
r
s
e
F
r
a
c
t
i
o
n
Pa
s
s
e
s
N
o
.
4
S
i
e
v
e
Si
l
t
s
a
n
d
C
l
a
y
s
Li
q
u
i
d
L
i
m
i
t
L
e
s
s
t
h
a
n
5
0
Si
l
t
s
a
n
d
C
l
a
y
s
Li
q
u
i
d
L
i
m
i
t
5
0
o
r
M
o
r
e
(1
)
(1
)
12
%
F
i
n
e
s
5%
F
i
n
e
s
(2
)
(2
)
(2
)
(2
)
Terms Describing Relative
Density and Consistency
Estimated Percentage Moisture Content
Percentage by Weight
<5
5 to <12
12 to <30
30 to <50
Component Definitions
Component
Trace
Some
Modifier
(silty, sandy, gravelly)
Very modifier
(silty, sandy, gravelly)
Size Range and Sieve Number
Larger than 12"
Descriptive Term
Smaller than No. 200 (0.075 mm)
3" to 12"
Coarse-
Grained Soils
Fine-
Grained Soils
Density
Very Loose
Loose
Medium Dense
Dense
Very Dense
SPT blows/foot
0 to 4
4 to 10
10 to 30
30 to 50
>50
(3)
0 to 2
2 to 4
4 to 8
8 to 15
15 to 30
>30
Consistency
Very Soft
Soft
Medium Stiff
Stiff
Very Stiff
Hard
SPT blows/foot(3)
Test Symbols
No. 4 (4.75 mm) to No. 200 (0.075 mm)
Boulders
Silt and Clay
Gravel
Coarse Gravel
Fine Gravel
Cobbles
Sand
Coarse Sand
Medium Sand
Fine Sand
Dry - Absence of moisture,
dusty, dry to the touch
Slightly Moist - Perceptible
moisture
Moist - Damp but no visible
water
Very Moist - Water visible but
not free draining
Wet - Visible free water, usually
from below water table
G = Grain Size
M = Moisture Content
A = Atterberg Limits
C = Chemical
DD = Dry Density
K = Permeability
No. 4 (4.75 mm) to No. 10 (2.00 mm)
No. 10 (2.00 mm) to No. 40 (0.425 mm)
No. 40 (0.425 mm) to No. 200 (0.075 mm)
3" to No. 4 (4.75 mm)
3" to 3/4"
3/4" to No. 4 (4.75 mm)
Symbols
Sampler Type and Description
Blows/6" or portion of 6"15
10
20
California Sampler
Ring Sampler
Continuous Sampling
Grab Sample
Portion not recovered
Split-Spoon Sampler (SPT)
Cement grout
surface seal
Bentonite seal
Filter pack with
blank casing
section
Screened casing
or Hydrotip with
filter pack
End cap
ATD
At time
of drilling
Static water
level (date)
(1)Percentage by dry weight
(2)Combined USCS symbols used for fines between 5% and 12%
(3)(SPT) Standard Penetration Test (ASTM D-1586)
(4)In General Accordance with Standard Practice for Description
and Identification of Soils (ASTM D-2488)
Groundwater
depth
i n c o r p o r a t e d
e a r t h s c i e n c e s
a s s o c i a t e d
EXPLORATION LOG KEY FIGURE:
A1Bl
o
c
k
s
\
d
w
g
\
l
o
g
_
k
e
y
2
0
2
2
.
d
w
g
L
A
Y
O
U
T
:
L
a
y
o
u
t
5
-
2
0
2
2
L
o
g
d
r
a
f
t
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
0
2.5
5
7.5
10
12.5
15
17.5
1
2
Grass/Fill
Dense, slightly moist, brown, gravelly, silty, fine SAND to silty, sandy,
GRAVEL; unsorted; contains concrete fragments and trash (SM-GM)
As above.
No groundwater encountered.
Associated Earth Sciences, Inc.
Exploration Boring HA-1
Renton New Life Church 1
Renton, WA Start Date:8/18/22 Logged By:KAM
20140005E001 Ending Date:8/18/22 Approved By:JHS
Driller/Equipment:Hand Auger Total Depth (ft):2.5
Hammer Weight/Drop:N/A Ground Surface Elevation (ft):»107
Hole Diameter (in):6 Datum:NAVD88
Groundwater Depth ATD (ft):N/A Groundwater Depth Post Drilling (ft) (Date): N/A ()
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Sa
m
p
l
e
%
R
e
c
o
v
e
r
y
Gr
a
p
h
i
c
Sy
m
b
o
l
Description
Wa
t
e
r
L
e
v
e
l
Bl
o
w
s
/
6
"
Blows/Foot
1
0
2
0
3
0
4
0
5
0
+
Ot
h
e
r
T
e
s
t
s
20
1
4
0
0
0
5
E
0
0
1
8/
2
6
/
2
0
2
2
Sheet: 1 of 1
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
0
2.5
5
7.5
10
12.5
15
17.5
1 Grass/Fill
Dense, slightly moist, brown, gravelly, silty, fine SAND to silty, sandy,
GRAVEL; contains fragments of concrete; unsorted (SM-GM).
No groundwater encountered.
Associated Earth Sciences, Inc.
Exploration Boring HA-2
Renton New Life Church 1
Renton, WA Start Date:8/18/22 Logged By:KAM
20140005E001 Ending Date:8/18/22 Approved By:JHS
Driller/Equipment:Hand Auger Total Depth (ft):2
Hammer Weight/Drop:N/A Ground Surface Elevation (ft):»107
Hole Diameter (in):6 Datum:NAVD88
Groundwater Depth ATD (ft):N/A Groundwater Depth Post Drilling (ft) (Date): N/A ()
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Sa
m
p
l
e
%
R
e
c
o
v
e
r
y
Gr
a
p
h
i
c
Sy
m
b
o
l
Description
Wa
t
e
r
L
e
v
e
l
Bl
o
w
s
/
6
"
Blows/Foot
1
0
2
0
3
0
4
0
5
0
+
Ot
h
e
r
T
e
s
t
s
20
1
4
0
0
0
5
E
0
0
1
8/
2
6
/
2
0
2
2
Sheet: 1 of 1
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
0
2.5
5
7.5
10
12.5
15
17.5
1
2
Grass/Fill
Dense, slightly moist, dark brown, gravelly, silty, fine SAND to silty, sandy,
GRAVEL; unsorted; contains concrete fragments and debris (SM-GM).
Becomes moist.
No groundwater encountered.
Associated Earth Sciences, Inc.
Exploration Boring HA-3
Renton New Life Church 1
Renton, WA Start Date:8/18/22 Logged By:KAM
20140005E001 Ending Date:8/18/22 Approved By:JHS
Driller/Equipment:Hand Auger Total Depth (ft):2
Hammer Weight/Drop:N/A Ground Surface Elevation (ft):»106
Hole Diameter (in):6 Datum:NAVD88
Groundwater Depth ATD (ft):N/A Groundwater Depth Post Drilling (ft) (Date): N/A ()
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Sa
m
p
l
e
%
R
e
c
o
v
e
r
y
Gr
a
p
h
i
c
Sy
m
b
o
l
Description
Wa
t
e
r
L
e
v
e
l
Bl
o
w
s
/
6
"
Blows/Foot
1
0
2
0
3
0
4
0
5
0
+
Ot
h
e
r
T
e
s
t
s
20
1
4
0
0
0
5
E
0
0
1
8/
2
6
/
2
0
2
2
Sheet: 1 of 1
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A
DocuSign Envelope ID: 8DC95E5E-DFD2-4FC3-AECA-A837B4E4B02A