HomeMy WebLinkAboutC_Geotechnical report_220531_v1
________________________________________________
3213 Eastlake Avenue East, Suite B
Seattle, WA 98102
T. (206) 262-0370
F. (206) 262-0374
Geotechnical & Earthquake
Engineering Consultants
May 24, 2022
PanGEO Project No. 22-187
Rick Miller
439 Renton Avenue South
Renton, WA 98057
Subject: Geotechnical Study - Geologic Hazards Evaluation
Proposed Addition
439 Renton Avenue South, Renton, WA
Dear Mr. Miller:
As requested, PanGEO, Inc. completed a geotechnical study to evaluate the geologic
hazard areas mapped at the site for the proposed house addition project. This study was
performed in general accordance with our mutually agreed scope of work outlined in our
proposal dated April 11, 2022. Our service scope included reviewing readily-available
geologic and geotechnical data in the project vicinity, reviewing preliminary design
plans, drilling three test borings, conducting a site reconnaissance, and developing the
recommendations and conclusions presented in this report.
SITE AND PROJECT DESCRIPTION
The project site is located at 439 Renton Avenue South in the City of Renton,
Washington (see Figure 1, Vicinity Map). The subject property is an approximately
15,000 square foot, rectangular-shaped parcel. It is bordered by Renton Avenue South to
the east, and existing residences to the other three sides. The site is currently occupied by
a one-story single-family house with a daylight basement in the east portion of the site. A
concrete paved driveway located on the north side of the house, between the garage and
Renton Avenue South. The layout of the site is shown on Figure 2, Site and Exploration
Plan.
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 2 - PanGEO, Inc.
The existing site grade generally slopes down from southeast to northwest with an
average gradient of about 17 percent according to the city’s COR Maps and King County
iMap. Up to 5-foot-tall concrete retaining walls were along both sides of the driveway
(see Plates 1 and 2, below).
We understand that the proposed project consists of constructing an addition to the north
and west sides of the existing house. The existing building will remain and be remodeled.
The existing deck will be demolished and replaced with a new two-story addition and a
deck. The majority of the site to the west and east of the house will remain as is.
We understand that the property contains landslide hazard, erosion hazard, and sensitive
slope areas as defined by the Renton Municipal Code (RMC). As a result, a geotechnical
study is required by the City to evaluate site stability (RMC 4-3-050F.2).
The conclusions and recommendations outlined in this report are based on our
understanding of the proposed improvements, which is in turn based on the project
information provided to us. If the above project description is substantially different
from your proposed improvements, or if the project scope changes, PanGEO should be
consulted to review the recommendations contained in this study and make
modifications, if needed.
Plate 1. Front view of the house, looking northwest. Plate 2. Rear view of the house, looking southeast.
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 3 - PanGEO, Inc.
SUBSURFACE EXPLORATIONS AND CONDITIONS
GEOLOGY
According to the Geologic Map of the Renton Quadrangle, King County, Washington
(Mullineaux, 1965), the surficial geologic unit at the subject site is mapped as Renton
formation (geologic map unit Tr). Renton formation consists of Eocene-aged sandstone
interbedded with siltstone, claystone, and coal.
TEST BORINGS
Three borings (PG-1 through PG-3) were drilled at the site on April 19, 2022, using a
CAT track drill owned and operated by Geologic Drill Partners of Fall City, Washington
under contract to PanGEO. The borings were drilled to a maximum depth of about 11½
and 16⅓ feet below existing grade. The approximate boring locations were located in the
field by measuring from property corners and site features and are shown on Figure 2.
The test borings were drilled using 6-inch outside diameter hollow stem augers. Standard
Penetration Tests (SPT) were performed in the borings at 2½-foot depth intervals using a
standard, 2-inch diameter split-spoon sampler. The sampler was advanced with a 140-
pound drop hammer falling a distance of 30 inches for each strike, in general accordance
with ASTM D-1586, Standard Test Method for Penetration Test and Split Barrel
Sampling of Soils. The number of blows required for each 6-inch increment of sampler
penetration was recorded. The number of blows required to achieve the last 12 inches of
sample penetration is defined as the SPT N-value. The N-value provides an empirical
measure of the relative density of cohesionless soil, or the relative consistency of fine-
grained soils.
A geologist from PanGEO was present during the field explorations to observe the
drilling, assist in sampling, and describe and document the soil samples obtained from the
borings. The soil samples retrieved from the borings were described using the system
outlined on Figure A-1. The summary test boring logs are included in Appendix A as
Figures A-2 through A-4.
SUBSURFACE CONDITIONS
The soil conditions encountered in the test borings completed at the site were generally
consistent. In summary, each test boring encountered native sandstone (bedrock) from
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 4 - PanGEO, Inc.
the surface to the bottoms of exploration. This soil unit extended to at least 16⅓ feet
below existing grade. We interpret this soil unit as the Renton formation mapped at the
site. This unit is weathered to a loose residual soil to a depth of 3 to 7 feet. Please refer to
the summary boring logs (Figures A-2 through A-4) for additional details.
Groundwater was not encountered within the depths of our test borings during drilling. It
should be noted that groundwater elevations and seepage rates are likely to vary
depending on the season, local subsurface conditions, and other factors. Groundwater
levels and seepage rates are normally highest during the winter and early spring.
GEOLOGICALLY HAZARDOUS AREAS EVALUATION
According to the City of Renton COR Maps, the site mapped as landslide and erosion
hazard areas and contains sensitive slopes. However, the site is not mapped within
seismic and coal mine hazard areas. The City’s criteria for the geologic hazard areas and
our assessment of the hazard areas with respect to the planned improvements are
provided in the following sections of this report.
SITE RECONNAISSANCE
We conducted a site reconnaissance on April 12, 2022. During our site visit, we looked
for signs of instabilities such as tension cracks in the ground, hummocky ground surface,
slumping of ground surface, change in vegetation patterns, among others. Based on our
observations, we did not notice any signs of instabilities within the property or its
immediate vicinity. The existing house foundations and retaining walls are observed to be
in a fair condition. Based on the results of our field exploration and the gentle
topography at the site, it is our opinion that the site is currently is stable. It is also our
opinion that the proposed addition, as currently planned, will not decrease the site
stability or adversely impact the subject site and surrounding properties.
LIDAR IMAGE
As part of our study, we reviewed a LiDAR image of the site and its vicinity. A portion
of the LiDAR image is shown in the attached Figure 3. A review of LiDAR image
indicates that the slopes in the immediate vicinity of the site have been highly modified
by previous construction activities. The LiDAR image also shows no signs of landslide
activities on the property or its immediate vicinity. The nearest landslide feature is
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 5 - PanGEO, Inc.
located at least 400 feet east of the site, between Beacon Way South and the Cedar River
(see Figure 3). The slide features at least 400 feet east of the site occur on a different
aspect (east-facing) slope, occur on slopes significantly larger and steeper than those at
the subject site, occur in a different geologic unit, and are largely due to the Cedar River
undercutting the toe of the slopes. In our opinion, the conditions that are causing the
landslides at least 400 feet east of the subject site are not present at the subject site.
SENSITIVE SLOPE REVIEW
According to the City’s definition (RMC 4-3-050G), sites that meet the following criteria
are considered 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.
The existing site grade generally slopes down from southeast to northwest with an
average gradient of about 17 percent according to the city’s COR Maps and King County
iMap. Review of the city’s COR Maps (see Plate 3, next page), the most area of the site
is mapped as a gentle slope (>15% & <=25%) with two localized areas located near the
northwest corner of the house and to the west of the south neighboring house are mapped
as sensitive slopes (>25% & <=40%). However, these two mapped sensitive slopes are
currently a concrete retaining wall and a rockery which were created by previous legal
site grading for the existing development. In our opinion, these two localized areas
should be excluded from the defined sensitive slopes.
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 6 - PanGEO, Inc.
LANDSLIDE HAZARD REVIEW
According to the City’s definition (RMC 4-3-050G), sites that meet the following criteria
are considered Medium Landslide Hazard Areas:
Areas with slopes between fifteen percent (15%) and forty percent (40%) and
underlain by soils that consist largely of sand, gravel or glacial till.
Based on our review of the City of Renton COR Maps, the site is mapped as a Medium
Landslide Hazard area. Review of the site topography and results of our subsurface
explorations the site has an average gradient of about 17% and is underlain by sandstone
(bedrock). Although the site gradient is between 15% and 40%, our borings did not
encounter sand, gravel, or glacial till. As such, in our opinion, the site does not meet the
Medium Landslide Hazard defined by RMC.
According to the Geologic Map of the Renton Quadrangle, King County, Washington
(Mullineaux, 1965), the site and its vicinity is underlain by Renton formation (geologic
map unit Tr). Renton formation typically consists of Eocene-aged sandstone interbedded
Plate 3. City of Renton slope mapping near project site (credit COR Maps).
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 7 - PanGEO, Inc.
with siltstone, claystone, and coal. The sandstone and siltstone generally exhibit very
dense and hard properties. Typically, landslide does not occur in Renton formation due to
its geologic settings.
Based on our review of the site geology and LiDAR image, and our observations made
during our site reconnaissance, it is our opinion that the site is stable in its current
configuration, and the risk of landslide is low. The proposed addition may be constructed
as planned and will not impact the stability of the site
EROSION HAZARD REVIEW
According to the City’s definition (RMC 4-3-050G), sites that meet the following criteria
are considered High Erosion Hazard:
Areas with soils characterized by the Natural Resource Conservation Service
(formerly U.S. Soil Conservation Service) as having severe or very severe erosion
potential, and a slope more than fifteen percent (15%).
Based on our review of the City of Renton COR Maps, the site is mapped as a High
Erosion Hazard area. We further researched the USDA Natural Resource Conservation
Service (NRSC) Soil Survey for surficial soil information. Review of the soil maps on the
Web Soil Survey indicates the site is underlain by Beausite gravelly sandy loam, 15 to 30
percent slopes (Map Unit BeD). The Beausite gravelly sandy loam, 15 to 30 percent
slopes material is described as having a severe erosion hazard when disturbed and left
unprotected.
However, based on the actual soil conditions (sandstone) encountered in the borings and
the site topography, it is our opinion that the erosion hazard at the site is considered low,
and can be effectively mitigated with the best management practice (BMPs) during
construction and with properly designed and implemented landscaping for permanent
erosion control. During construction, the temporary erosion hazard can also be effectively
managed with an appropriate erosion and sediment control plan, including but not limited
to installing a silt fence at the construction perimeter, placing quarry spalls or hay bales at
the disturbed and traffic areas, covering stockpiled soil or cut slopes with plastic sheets,
constructing a temporary drainage pond to control surface runoff and sediment trap,
placing rocks at the construction entrance, etc.
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 8 - PanGEO, Inc.
Permanent erosion control measures should be applied to the disturbed areas as soon as
feasible. These measures may include but not limited to planting and hydroseeding. The
use of permanent erosion control mat may also be considered in conjunction with
planting/hydroseeding to protect the soils from erosion.
CONCLUSIONS
In summary, our test borings completed at the site encountered competent sandstone
(Renton formation) at shallow depths, and a review of LiDAR image indicates no
landslide activities within about 400 feet of the site. It is our opinion that the proposed
addition may be constructed as planned and would not compromise the site stability.
Because the landslide hazard, erosion hazard, and sensitive slope are mapped on the
project site, the City requires a geotechnical study to evaluate site stability. The study
shall be performed to meet the City’s requirements outlined in RMC4-3-050F.2. The
required study shall demonstrate the following criteria can be met:
a. The proposal will not increase the threat of the geological hazard to adjacent or
abutting properties beyond pre-development conditions; and
b. The proposal will not adversely impact other critical areas; and
c. The development can be safely accommodated on the site.
Based on the subsurface conditions at the site and results of our geotechnical study, it is
our opinion that the proposed project meets the criteria above.
CLOSURE
We have prepared this report for Mr. Rick Miller and the project design team.
Recommendations contained in this report are based on a site reconnaissance, a
subsurface exploration program, review of pertinent subsurface information, and our
understanding of the project. The study was performed using a mutually agreed-upon
scope of work.
Variations in soil conditions may exist between the locations of the explorations and the
actual conditions underlying the site. The nature and extent of soil variations may not be
evident until construction occurs. If any soil conditions are encountered at the site that
are different from those described in this report, we should be notified immediately to
review the applicability of our recommendations. Additionally, we should also be
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 9 - PanGEO, Inc.
notified to review the applicability of our recommendations if there are any changes in
the project scope.
The scope of our work does not include services related to construction safety
precautions. Our recommendations are not intended to direct the contractors’ methods,
techniques, sequences or procedures, except as specifically described in our report for
consideration in design. Additionally, the scope of our work specifically excludes the
assessment of environmental characteristics, particularly those involving hazardous
substances. We are not mold consultants nor are our recommendations to be interpreted
as being preventative of mold development. A mold specialist should be consulted for all
mold-related issues.
This report has been prepared for planning and design purposes for specific application to
the proposed project in accordance with the generally accepted standards of local practice
at the time this report was written. No warranty, express or implied, is made.
This report may be used only by the client and for the purposes stated, within a
reasonable time from its issuance. Land use, site conditions (both off and on-site), or
other factors including advances in our understanding of applied science, may change
over time and could materially affect our findings. Therefore, this report should not be
relied upon after 24 months from its issuance. PanGEO should be notified if the project
is delayed by more than 24 months from the date of this report so that we may review the
applicability of our conclusions considering the time lapse.
It is the client’s responsibility to see that all parties to this project, including the designer,
contractor, subcontractors, etc., are made aware of this report in its entirety. The use of
information contained in this report for bidding purposes should be done at the
contractor’s option and risk. Any party other than the client who wishes to use this report
shall notify PanGEO of such intended use and for permission to copy this report. Based
on the intended use of the report, PanGEO may require that additional work be performed
and that an updated report be reissued. Noncompliance with any of these requirements
will release PanGEO from any liability resulting from the use this report.
We appreciate the opportunity to be of service. Should you have any questions, please do
not hesitate to call.
Sincerely,
PanGEO, Inc.
Geotechnical Study - Geologic Hazards Evaluation
439 Renton Ave S, Renton, WA
May 24, 2022
22-187 439 Renton Ave S Rpt - 10 - PanGEO, Inc.
05/24/2022
Bart Weitering, G.I.T. Chien-Lin (Johnny) Chen, P.E.
Project Geologist Senior Geotechnical Engineer
Attachments:
Figure 1. Vicinity Map
Figure 2. Site and Exploration Plan
Figure 3. LiDAR Map
Appendix A Summary Test Boring Logs
Figure A-1 Terms and Symbols for Boring and Test Pit Logs
Figure A-2 Log of Test Boring PG-1
Figure A-3 Log of Test Boring PG-2
Figure A-4 Log of Test Boring PG-3
Figure No.Project No.22-187
Proposed Addition
439 Renton Avenue South
Renton, Washington
1file.grf w/ file.dat 5/20/22 (12:47:44) BWBase Map: ESRI Topographic
VICINITY MAP
Approx. Scale:
Not to Scale
NORTH
Project Site
Lake
Washington
Puget
Sound
Green Lake
Project No.Figure No.
Proposed Addition
439 Renton Avenue South
Renton, Washington
SITE AND EXPLORATION PLAN
22-187 2
Approx. Test Boring Location
Approx. Proposed Addition Footprint
Approx. Scale
1" = 20'
Base map modified from Sheet A0.0 SITE/INFO by Brett Wiemann Design, LLC dated January 12, 2022Legend:
PG-1
PG-2
PG-3
Existing House
Garage
Retaining Wall
Figure No.Project No.22-187
Proposed Addition
439 Renton Avenue South
Renton, Washington
3
LiDAR Map
Note: Base map modified from PSLC King County 2016-2017 LiDAR
Final Technical Data Report by Quantum Spatial dated June 23, 2017
Approx. Scale
1" = 300'Approx. Site Boundary
Legend:
PIT-1 Interstate 5Renton Ave SBe
a
c
o
n
W
a
y
S
S 4th Street
Cedar Ave SMill Ave SS 3rd StreetCedar
River
Grant Ave S
Appendix A
Summary Test Boring Logs
MOISTURE CONTENT
2-inch OD Split Spoon, SPT
(140-lb. hammer, 30" drop)
3.25-inch OD Spilt Spoon
(300-lb hammer, 30" drop)
Non-standard penetration
test (see boring log for details)
Thin wall (Shelby) tube
Grab
Rock core
Vane Shear
Dusty, dry to the touch
Damp but no visible water
Visible free water
Terms and Symbols for
Boring and Test Pit Logs
Density
SILT / CLAY
GRAVEL (<5% fines)
GRAVEL (>12% fines)
SAND (<5% fines)
SAND (>12% fines)
Liquid Limit < 50
Liquid Limit > 50
Breaks along defined planes
Fracture planes that are polished or glossy
Angular soil lumps that resist breakdown
Soil that is broken and mixed
Less than one per foot
More than one per foot
Angle between bedding plane and a planenormal to core axis
Very Loose
Loose
Med. Dense
Dense
Very Dense
SPT
N-values
Approx. Undrained Shear
Strength (psf)
<4
4 to 10
10 to 30
30 to 50
>50
<2
2 to 4
4 to 8
8 to 15
15 to 30
>30
Units of material distinguished by color and/orcomposition from material units above and below
Layers of soil typically 0.05 to 1mm thick, max. 1 cm
Layer of soil that pinches out laterally
Alternating layers of differing soil material
Erratic, discontinuous deposit of limited extent
Soil with uniform color and composition throughout
Approx. Relative
Density (%)
Gravel
Layered:
Laminated:
Lens:
Interlayered:
Pocket:
Homogeneous:
Highly Organic Soils
#4 to #10 sieve (4.5 to 2.0 mm)
#10 to #40 sieve (2.0 to 0.42 mm)
#40 to #200 sieve (0.42 to 0.074 mm)
0.074 to 0.002 mm
<0.002 mm
UNIFIED SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS GROUP DESCRIPTIONS
Notes:
MONITORING WELL
SPT
N-values
<15
15 - 35
35 - 65
65 - 85
85 - 100
GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
TEST SYMBOLS
50%or more passing #200 sieve
Groundwater Level attime of drilling (ATD)Static Groundwater Level
Cement / Concrete Seal
Bentonite grout / seal
Silica sand backfill
Slotted tip
Slough
<250
250 - 500
500 - 1000
1000 - 2000
2000 - 4000
>4000
RELATIVE DENSITY / CONSISTENCY
Fissured:
Slickensided:
Blocky:
Disrupted:
Scattered:
Numerous:
BCN:
COMPONENT DEFINITIONS
Dry
Moist
Wet
1. Soil exploration logs contain material descriptions based on visual observation and field tests using a systemmodified from the Uniform Soil Classification System (USCS). Where necessary laboratory tests have beenconducted (as noted in the "Other Tests" column), unit descriptions may include a classification. Please refer to thediscussions in the report text for a more complete description of the subsurface conditions.
2. The graphic symbols given above are not inclusive of all symbols that may appear on the borehole logs.Other symbols may be used where field observations indicated mixed soil constituents or dual constituent materials.
COMPONENT SIZE / SIEVE RANGE COMPONENT SIZE / SIEVE RANGE
SYMBOLS
Sample/In Situ test types and intervals
Silt and Clay
Consistency
SAND / GRAVEL
Very Soft
Soft
Med. Stiff
Stiff
Very Stiff
Hard
Phone: 206.262.0370
Bottom of BoringBoulder:
Cobbles:
Gravel
Coarse Gravel:
Fine Gravel:
Sand
Coarse Sand:
Medium Sand:
Fine Sand:
Silt
Clay
> 12 inches
3 to 12 inches
3 to 3/4 inches
3/4 inches to #4 sieve
Figure A-1
Atterberg Limit Test
Compaction Tests
Consolidation
Dry Density
Direct Shear
Fines Content
Grain Size
Permeability
Pocket Penetrometer
R-value
Specific Gravity
Torvane
Triaxial Compression
Unconfined Compression
Sand
50% or more of the coarse
fraction passing the #4 sieve.
Use dual symbols (eg. SP-SM)for 5% to 12% fines.
for In Situ and Laboratory Testslisted in "Other Tests" column.
50% or more of the coarsefraction retained on the #4sieve. Use dual symbols (eg.GP-GM) for 5% to 12% fines.
DESCRIPTIONS OF SOIL STRUCTURES
Well-graded GRAVEL
Poorly-graded GRAVEL
Silty GRAVEL
Clayey GRAVEL
Well-graded SAND
Poorly-graded SAND
Silty SAND
Clayey SAND
SILT
Lean CLAY
Organic SILT or CLAY
Elastic SILT
Fat CLAY
Organic SILT or CLAY
PEAT
ATT
Comp
Con
DD
DS
%F
GS
Perm
PP
R
SG
TV
TXC
UCC
LOG KEY 16-056_LOGS.GPJ PANGEO.GDT 02/22/16
SANDSTONE, dark brown to brown, very fine to fine grained, very thinly
bedded to laminated, residual soil, extremely weak rock [Tr - RentonFormation].
SANDSTONE, orange and very light gray, fine to medium grained, thinlybedded, subarkose, completely weathered/altered, extremely weak rock [Tr- Renton Formation].
SANDSTONE, white to very light gray with some orange, fine to medium
grained, thinly bedded, subarkose, highly weathered/altered, very weakrock [Tr - Renton Formation].
Boring terminated at about 16.3 feet below ground surface. Groundwater
was not observed during drilling.
S-1
S-2
S-3
S-4
S-5
3
4
3
2
2
2
8
7
18
16
20
25
12
35
50/4
Surface Elevation:
Top of Casing Elev.:
Drilling Method:
Sampling Method:
MATERIAL DESCRIPTION
Figure A-2Other TestsRemarks: Boring drilled using a Bobcat track drill rig. Standard penetration test (SPT) samplerdriven with a 140 lb. safety hammer. Hammer operated with a rope and cathead mechanism.
Surface elevation estimated from Sheet A0.0 SITE/INFO by Brett Wiemann Design, LLC dated
January 12, 2022.
0
2
4
6
8
10
12
14
16
18
20
The stratification lines represent approximate boundaries. The transition may be gradual.Sample No.LOG OF TEST BORING PG-1
Completion Depth:
Date Borehole Started:
Date Borehole Completed:
Logged By:
Drilling Company:Depth, (ft)Miller Residence - Proposed Addition
22-187
439 Renton Ave S, Renton, WA
Northing: 47.4767, Easting: -122.2008
16.3ft
4/19/22
4/19/22
B. Weitering
Geologic Drill Partners
Sheet 1 of 1
Project:
Job Number:
Location:
Coordinates:SymbolSample TypeBlows / 6 in.240.0ft
N/A
HSA
SPT
0 100
Moisture LL
N-Value
50
PL
RQD Recovery
>>
SANDSTONE, dark brown to brown, very fine to fine grained, very thinly
bedded to laminated, residual soil, extremely weak rock [Tr - RentonFormation].
SANDSTONE, orange and very light gray, fine to medium grained, thinly
bedded, subarkose, completely weathered/altered, extremely weak rock [Tr- Renton Formation].
SANDSTONE, white to very light gray and orange, fine to medium grained,thinly bedded, subarkose, highly weathered/altered, very weak rock [Tr -
Renton Formation].
Boring terminated at about 11.5 feet below ground surface. Groundwaterwas not observed during drilling.
S-1
S-2
S-3
S-4
2
5
9
17
21
24
14
20
24
17
24
35
Surface Elevation:
Top of Casing Elev.:
Drilling Method:
Sampling Method:
MATERIAL DESCRIPTION
Figure A-3Other TestsRemarks: Boring drilled using a Bobcat track drill rig. Standard penetration test (SPT) samplerdriven with a 140 lb. safety hammer. Hammer operated with a rope and cathead mechanism.
Surface elevation estimated from Sheet A0.0 SITE/INFO by Brett Wiemann Design, LLC dated
January 12, 2022.
0
2
4
6
8
10
12
14
16
18
20
The stratification lines represent approximate boundaries. The transition may be gradual.Sample No.LOG OF TEST BORING PG-2
Completion Depth:
Date Borehole Started:
Date Borehole Completed:
Logged By:
Drilling Company:Depth, (ft)Miller Residence - Proposed Addition
22-187
439 Renton Ave S, Renton, WA
Northing: 47.47655, Easting: -122.20085
11.5ft
4/19/22
4/19/22
B. Weitering
Geologic Drill Partners
Sheet 1 of 1
Project:
Job Number:
Location:
Coordinates:SymbolSample TypeBlows / 6 in.248.0ft
N/A
HSA
SPT
0 100
Moisture LL
N-Value
50
PL
RQD Recovery
SANDSTONE, dark brown to brown, very fine to fine grained, very thinly
bedded to laminated, residual soil, extremely weak rock [Tr - RentonFormation].
SANDSTONE, orange and very light gray, fine to medium grained, thinly
bedded, subarkose, completely weathered/altered, extremely weak rock [Tr- Renton Formation].
Boring terminated at about 11.5 feet below ground surface. Groundwaterwas not observed during drilling.
S-1
S-2
S-3
S-4
4
10
17
10
20
31
20
22
30
16
20
33
Surface Elevation:
Top of Casing Elev.:
Drilling Method:
Sampling Method:
MATERIAL DESCRIPTION
Figure A-4Other TestsRemarks: Boring drilled using a Bobcat track drill rig. Standard penetration test (SPT) samplerdriven with a 140 lb. safety hammer. Hammer operated with a rope and cathead mechanism.
Surface elevation estimated from Sheet A0.0 SITE/INFO by Brett Wiemann Design, LLC dated
January 12, 2022.
0
2
4
6
8
10
12
14
16
18
20
The stratification lines represent approximate boundaries. The transition may be gradual.Sample No.LOG OF TEST BORING PG-3
Completion Depth:
Date Borehole Started:
Date Borehole Completed:
Logged By:
Drilling Company:Depth, (ft)Miller Residence - Proposed Addition
22-187
439 Renton Ave S, Renton, WA
Northing: 47.47665, Easting: -122.201
11.5ft
4/19/22
4/19/22
B. Weitering
Geologic Drill Partners
Sheet 1 of 1
Project:
Job Number:
Location:
Coordinates:SymbolSample TypeBlows / 6 in.230.0ft
N/A
HSA
SPT
0 100
Moisture LL
N-Value
50
PL
RQD Recovery