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HomeMy WebLinkAboutEx06_Geotechnical_Report ________________________________________________ 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. RECEIVED PLANNING DIVISION 07/20/2022 AVanGordon DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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. DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 gene ral 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 i nches 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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. DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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). DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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. DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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. DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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, 2022 Legend: PG-1 PG-2 PG-3 Existing House Garage Retaining Wall DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 SDocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 Appendix A Summary Test Boring Logs DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 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 MAJ OR 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 at time 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 system modified from the Uniform Soil Classification System (USCS). Where necessary laboratory tests have been conducted (as noted in the "Other Tests" column), unit descriptions may include a classification. Please refer to the discussions 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 Tests listed in "Other Tests" column. 50% or more of the coarse fraction retained on the #4 sieve. 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 02/22/16DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 SANDSTONE, dark brown to brown, very fine to fine grained, very thinly bedded to laminated, residual soil, extremely weak rock [Tr - Renton Formation]. 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 with some orange, fine to medium grained, thinly bedded, subarkose, highly weathered/altered, very weak rock [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) sampler driven 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 >> DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 SANDSTONE, dark brown to brown, very fine to fine grained, very thinly bedded to laminated, residual soil, extremely weak rock [Tr - Renton Formation]. 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. Groundwater was 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) sampler driven 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9 SANDSTONE, dark brown to brown, very fine to fine grained, very thinly bedded to laminated, residual soil, extremely weak rock [Tr - Renton Formation]. 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. Groundwater was 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) sampler driven 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 DocuSign Envelope ID: 943BE2E0-EBD6-4605-A0EE-7915BAA4E8A9