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Report (2) h RECEIVED 1SN1 OFFICE COPY G 9750 SW Nimbus venue CITY OF TIGARD Beaverton, OR 97 008-71 7 2 BUILDING DIVISION 503-641-3478 I www.gri.com MEMORANDUM To: Debbie Pearson/ DAY CPM Services, LLC Date:April 23, 2021 GRI Project No.: 5970-M From: A. Wesley Spang, PhD, PE, GE; Nicholas M. Hatch, PE; and Marissa P. Rauthause, PE Re: Additional Geotechnical Investigation Track and Field Light Poles Twality Middle School Tigard, Oregon At your request, GRI completed an additional geotechnical investigation for light pole foundation design at the Twality Middle School track and field in Tigard, Oregon. The approximate location of the Twality Middle School is shown on the Vicinity Map, Figure 1. GRI previously completed two geotechnical investigations for the proposed improvements to Twality Middle School, the results of which were provided to the Tigard-Tualatin School District in our June 28, 2017, report titled "Geotechnical Investigation and Site-Specific Seismic Hazard Evaluation, Twality Middle School, Tigard, Oregon," and our January 26, 2021, report titled "Geotechnical Investigation, Twality Middle School, Track and Field Upgrades, Tigard, Oregon." We understand four new light pole structures will be installed around the upgraded track and field located immediately east of the new school building. Information provided by Cardno, the project civil engineer, indicates the light poles will be 70 feet tall and weigh about 2,200 pounds each. We understand the light poles will be founded on 30-inch-diameter concrete piers. Two poles will be constructed on the western side of the field and two poles will be constructed on the eastern side of the field. The purpose of this investigation was to evaluate subsurface conditions at each light pole location and provide recommendations for founding the new light poles. The investigation included a review of available subsurface and geologic information for the site and surrounding area, subsurface explorations, laboratory testing, and engineering analyses. This memorandum summarizes our findings and provides our recommendations for design and construction of the light pole foundations. SUBSURFACE CONDITIONS General Subsurface materials and conditions at the proposed light pole locations were investigated on April 9, 2021, with four borings, designated B-1 through B-4. The borings were advanced to a depth of about 21.5 feet below existing site grades. The approximate locations of the borings completed for this investigation are shown on Figure 2. Logs of the explorations are provided on GRI PN#5970-M—Twality Middle School Track and Field Light Poles April 23,2021 I GFR. I Figures 1A through 4A. The field and laboratory programs conducted to evaluate the physical engineering properties of the materials encountered in the explorations are described in Appendix A. The terms and symbols used to describe the materials encountered in the explorations are defined in Table 1A and the attached legend. Soils For the purpose of discussion,the materials disclosed by the explorations have been grouped into the following units based on their physical characteristics and engineering properties: 1. PAVEMENT 2. FILL a. Gravel b. Sandy SILT to Silty SAND 3. Sandy SILT to Silty SAND The following paragraphs provide a description of the materials encountered in the explorations completed by GRI for this project and a discussion of the groundwater conditions at the site. 1. PAVEMENT Explorations B-3 and B-4 were advanced through the existing asphalt concrete (AC) pavement track and encountered about 4 inches of AC pavement at the ground surface. The pavement is underlain by about 8 inches of crushed-rock base (CRB) course. 2. FILL a. GRAVEL Fill consisting of gravel was encountered beneath the pavement section in boring B-4 and extends to a depth of about 5 feet below the track surface. In general, the gravel fill is subrounded to subangular and contains a trace of coarse-grained sand. The relative density of the gravel fill is loose based on a standard penetration test (SPT) N-value. b. Sandy SILT to Silty SAND Fill consisting of silty sand to sandy silt soil was encountered beneath the pavement in boring B-3 and below the gravel fill in boring B-4 and extends to a depth of about 10 feet below the surface of the existing track. In general, the sandy silt and silty sand fill is brown mottled gray, has a variable clay content ranging from trace to some clay, and contains fine-grained sand. Based on SPT N-values,the relative consistency of the sandy silt fill is very soft to medium stiff and the relative density of the silty sand fill is very loose to loose.The natural moisture content of the sandy silt and silty sand fill ranges from 23%to 29%. GRI PN#5970-M-Twality Middle School Track and Field Light Poles 2 April 23,2021 GRO 3. Sandy SILT to Silty SAND Interbedded layers of sandy silt to silty sand were encountered at the ground surface in borings B-1 and B-2 and below the fill in borings B-3 and B-4. The soils are generally brown to yellow- brown and extend to the maximum depth explored of about 21.5 feet. In general, the sandy silt contains fine-to medium-grained sand and trace to some clay,and the silty sand is fine to medium grained. Based on SPT N-values,the relative consistency of the silt is very soft to very stiff and the relative density of the silty sand is loose to medium dense. The natural moisture content of the silty sand to sandy silt soils ranges from 20%to 31%. Groundwater The borings were completed using mud-rotary drilling techniques, which do not allow direct measurement of groundwater levels at the time of drilling. Our review of U.S. Geological Survey (USGS) groundwater data suggests the regional groundwater level at the site typically occurs at depth in the highly fractured, hard basalt that underlies the site. However, our experience in the project vicinity indicates perched groundwater can occur in the fine-grained soils that mantle the site, particularly during the wet winter months or following periods of intense or prolonged precipitation. FINDINGS AND RECOMMENDATIONS General Subsurface explorations completed for this investigation indicate the eastern portion of the track and field is mantled with fill soils, which were likely placed from on-site excavations during mass grading for construction of the track and field. The fill soils extend to a depth of about 10 feet below the ground surface on the eastern edge of the track and field and are underlain by silty sand to sandy silt soils that also mantle the western portion of the track and field. We anticipate perched groundwater may approach the ground surface during the wet winter months or following periods of intense or prolonged precipitation. The primary geotechnical considerations associated with construction of the new light pole foundations include the potential for shallow, perched-groundwater conditions and the presence of fill soils.The following sections of this memorandum provide our geotechnical conclusions and recommendations for use in the design and construction of the four new embedded light pole foundations. Foundation Support General Information provided by Cardno,the project civil engineer, indicates the light poles will be 70 feet tall and weigh about 2,200 pounds each. We understand the light poles will be founded on 30- inch-diameter drilled concrete piers, and we anticipate pier embedment will be controlled by GRI PN#5970-M—Twality Middle School Track and Field Light Poles 3 April 23,2021 GR1 lateral-loading conditions. For this report, the subsurface units and corresponding depths have been generalized based on location and are tabulated in Table 1 below. Table 1:GENERALIZED SUBSURFACE PROFILE Depth Below Existing Site Grades, ft Soil Units B-1 B-2 B-3 B-4 FILL N/E N/E 0 to 10 0 to 10 ,_ 'Sandy SILT to Silty SAND •+ 0 t le1 S 0 to „ ..'• Note: N/E = Not Encountered. The generalized profiles are intended for use in axial and lateral load analyses of the drilled piers and reflect the general subsurface conditions encountered in the borings completed near the planned new light pole locations. It should be understood that subsurface variations between the specified locations exist, which can affect the axial and lateral performances of the drilled piers. If any new light poles are located between the boring locations, the generalized profile in Table 1 that results in the lowest axial and lateral capacities should be used for foundation design. Lateral Loading Lateral structural loads can be resisted by the structural strength of the drilled pier in bending. We anticipate the drilled-pier foundations will be evaluated using the computer software LPILE developed by Ensoft, Inc., of Austin, Texas. For the lateral-load analysis, we assumed the groundwater level occurs deeper than 25 feet below the ground surface. Recommended input parameters for the soil units in the LPILE analyses are provided in Table 2. Table 2:SOIL PROPERTIES FOR LPILE ANALYSIS Soil Properties Soil Unit Soil Type Condition K, pci y, pcf cl)' c, psf eso Static& FILL Silt 30 110 26° 0 0.02 Seismic Static 100 ' 115 32°'ia 0 0 01 ffi Seismic Static Axial Loading The static axial resistances for the drilled piers were analyzed using methods discussed in the Federal Highway Administration (FHWA) Publication FHWA-NHI-10-016, Drilled Shafts: Construction Procedures and LRFD Design Methods. The design methods estimate axial resistance based on given soil parameters and drilled-pier properties. Our analysis assumed the drilled piers would derive their axial resistance from skin-friction and end-bearing resistance. The allowable skin-friction resistances for each soil unit are tabulated in Table 3 below to evaluate axial and uplift capacities. GRI PN#5970-M—Twality Middle School Track and Field Light Poles 4 April 23, 2021 ♦ GRI Table 3:ALLOWABLE STATIC SKIN-FRICTION RESISTANCE VALUES Allowable Static Skin-Friction Soil Unit Resistance, psf FILL 50 Sandy SILT to Silty SAND ILTA to The skin-friction resistance over the top 5 feet of each pier should be neglected. An allowable static end-bearing resistance of 2 kips per square foot (ksf) may be used for piers embedded at least 10 feet below the ground surface in native soil. The allowable static values are based on assumed soil-support properties and provide factors of safety of at least 2 and 3 for skin-friction and end-bearing resistance, respectively. Minimum pier-embedment lengths to achieve the required axial and uplift capacities should be reviewed with lengths necessary to accommodate lateral-loading requirements; however, we anticipate lateral loading will govern the design. Seismic Considerations We anticipate the new light poles will be designed in accordance with the 2019 Oregon Structural Specialty Code (OSSC), which incorporates recommendations for seismic design from the American Society of Civil Engineers (ASCE) document 7-16, Minimum Design Loads for Building and Other Structures (ASCE 7-16). The ASCE 7-16 seismic-hazard levels are based on a Risk- Targeted Maximum Considered Earthquake (MCER) with the intent of including the probability of structural collapse. The ground motions associated with the probabilistic MCER represent a targeted risk level of 1%in 50 years probability of collapse in the direction of maximum horizontal response. In general, these risk-targeted ground motions are developed by applying adjustment factors of directivity and risk coefficients to the 2% probability of exceedance in 50 years,or 2,475- year return-period hazard level. The risk-targeted probabilistic values are also subject to a deterministic limit,which is computed from the models of earthquake sources and ground-motion propagation that form the basis of the 2014 USGS National Seismic Hazard Maps (NSHMs). The ASCE methodology uses two bedrock spectral response parameters, Ss and Si,corresponding to periods around 0.2 second and 1.0 second to develop the MCER response spectrum. To establish the ground-surface MCER spectrum, these bedrock spectral parameters are adjusted for site class using the short- and long-period site coefficients, Fa and F,,, in accordance with Section 11.4.3 of ASCE 7-16, which includes new seismic site coefficients to adjust the mapped values for soil properties. The Ss and Si parameters for the site located at the approximate latitude and longitude coordinates of 45.4141° N and 122.7738°W, are 0.85 g and 0.39 g, respectively, for Site Class B/C, or bedrock conditions. Based on the results of our subsurface investigation,we recommend using Site Class D to evaluate seismic design of the new light poles. Site coefficients Fa and F„of 1.16 and 1.91, respectively, were used to develop the Site Class D MCER-level spectrum in accordance GRI PN#5970-M—Twality Middle School Track and Field Light Poles 5 April 23,2021 G R ! I with Section 11.4 of ASCE 7-16. However, Section 11.4.8 of ASCE 7-16 requires a ground-motion hazard analysis be completed for structures on Site Class D sites to determine the F„ coefficient when the Si parameter is greater than or equal to 0.2 g. The code provides an exception that waives the ground-motion hazard analysis if the seismic-response coefficient, Cs, is determined in accordance with Section 11.4.8, Exception 2, of ASCE 7-16.We anticipate the response coefficient will be developed as discussed above; therefore, the code-based, Site Class D, ground-surface, MCER response spectrum is appropriate for design of the new poles. The design-level response spectrum is calculated as two thirds of the ground-surface MCER spectrum. The MCER-level and design-level response spectra coefficients are provided below in Table 4. Table 4:RECOMMENDED SEISMIC DESIGN PARAMETERS(2019 OSSC/ASCE 7-16) Seismic Parameter Recommended Value Site Class D MCER Spectral Response Acceleration •• i 0.99 g Parameter at Short Periods,SMs MCER Spectral Response Acceleration 0.74 g Parameter at 1.0-Sec Period, SMi Design Spectral Response Acceleration 1' r Parameter at Short Periods, Sos tt 4 I Design Spectral Response Acceleration 0.50 g Parameter at 1.0-Sec Period,Sol In terms of potential seismic-related hazards in the area,we anticipate there is a risk of liquefaction and minor cyclic softening of the silt and sand layers, respectively, below the groundwater level at the site. Based on the results of our previous investigation of the new Twality Middle School, we anticipate dynamic settlement due to liquefaction and cyclic softening could result in settlements on the order of about 1 inch at the light pole locations. However, based on the crust thickness and depth of the anticipated liquefaction/cyclic softening, we anticipate the risk of significant bearing capacity reduction and/or ground manifestation of the seismically induced settlement is low during a code-based earthquake. The risk of damage by tsunami and/or seiche at the site is absent. The inferred location of the Canby-Molalla Fault borders the southwestern corner of the site (Personius et al., 2003); however,the USGS does not consider the Canby-Molalla Fault to be an active, contributing source in their Probabilistic Seismic Hazard Analysis (PSHA). The USGS considers the Portland Hills Fault, located about 12 kilometers northeast of the site, to be the closest crustal fault source contributing to the overall seismic hazard at the site. Unless occurring on a previously unmapped or unknown fault, the risk of fault rupture at the site is low. GRI PN#5970-M—Twality Middle School Track and Field Light Poles 6 April 23, 2021 G ' RI LIMITATIONS This memorandum should be considered an addendum to our June 28, 2017, and January 26, 2021, reports for projects on the Twality Middle School campus and are subject to the limitations stated therein. Please contact the undersigned if you have any questions or need any additional information. Please contact the undersigned if you have any questions. Submitted for GRI, ��R�O PROPe, �G N f , /O ct� 18281 9 9 41,6'SLE Y SQPaG Expires 06-2022 /4/1."'" Y A. Wesley Spang, Ph.D, PE, GE Nicholas M. Hatch, P Marissa P. Rauthause, PE Principal Senior Engineer Project Engineer This document has been submitted electronically. References American Society of Civil Engineers, 2016, ASCE 7-16, Minimum design loads for buildings and other structures, Draft Copy,ASCE, Reston,Virginia. Madin,I.P., 1990, Earthquake-hazard geology maps of the Portland metropolitan area:Oregon Department of Geology and Mineral Studies,Open-File Report 90-02. Personius, S. F., Dart, R. L., Bradley, Lee-Ann, and Haller, K. M., 2003, Map and data for Quaternary faults and folds in Oregon:U.S.Geological Survey Open-File Report 03-095. U.S. Geological Survey (USGS), Unified hazard tool, Conterminous U.S. 2014(v4.0x), accessed 04/14/21 from USGS website:https://earthquake.usgs.gov/hazards/interactive/. USGS, 2018, U.S. Seismic Design Maps lookup by latitude, longitude, accessed 04/14/2021 from USGS website: https://earthquake.usgs.gov/designmaps/us/application.php TWALITY MS LIGHT POLES GEOTECH MEMO GRI PN #5970-M—Twality Middle School Track and Field Light Poles 7 April 23, 2021 --,. }J (I I oyk �- ��A .A I r..,_`_-may I A Q n .......:::::.... f / \ • • t B-1 / mu 4/1 44 / I �?` . /I Id 1 f11 I` .I J // /. ., /. ��� �.. ',cs r 'mot; � � I v ' B 3 r RE FIELD p / uoftracPou p 0 1TX:4t31DDLE SCHOOL /'- / ! O I 1 1 e 7 / r 1 / p 1 1 r /� O\ / •i r r 1 r am. Ate, �� ,/ / /: /j „ r r tr 1 \ fr BORING COMPLETED BY GRI f / (APRIL 9,2021) (440: /;-, ,�s ittiOgi , /, 7 C • r A,AAtte / ,!,\\ � / SITE PLAN FROM FILE BY CARDNO,2021 44,4#4,1G�1 k // �� pia� �V A Off/+�� � ✓ ! / .4,f41,,,,A,,wit* mil O 1 t 0 1 N 1= i ,;( 1 a 1 I , lii�� B-4 / �� / 0 60 120 FT wweEcRICAL / a I �, •L c0 I 1 , erg. © (t) ��- 0J f` 1 Itltro f ;O _ ---- T TIGARD TUALATIN SCHOOL DISTRICT iiip I • 1 ( ' (VT K11 TWALITY MIDDLE SCHOOL TRACK AND FIELD �P : J'esm�y [ 1 \ - LIGHT POLES . o \ .,./ 0VI, I v0R'� SITE PLAN td.; I. a rt::rstmu�ae�a�ra�aaaear®ga a ,. �. "1 fiti f t F•r rs� g ..., s ss r �ss ` APR.2021 JOB NO.5970-M FIG. 2 G RD APPENDIX A Field Explorations and Laboratory Testing GRI PN#5970-M—Twality Middle School Track and Field Light Poles April 23, 2021 G nn TT APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING FIELD EXPLORATIONS Subsurface materials and conditions at each of the four light pole locations were investigated on April 9, 2021, with four borings, designated B-1 through B-4. The approximate locations of the borings completed for this investigation are shown on Figure 2. Logs of the explorations are provided on Figures 1 A through 4A.The field-exploration work was coordinated and documented by an experienced member of GRI's geotechnical engineer staff, who maintained a log of the materials and conditions disclosed during the course of work. Borings B-1 through B-4 were advanced to a depth of about 21.5 feet below existing site grades. The borings were completed with mud-rotary drilling techniques using a Geoprobe 7822 DT track- mounted drill rig provided and operated by Western States Soil Conservation, Inc., of Hubbard, Oregon. Disturbed samples of soil were typically obtained from the borings at 2.5-foot intervals of depth in the upper 15 feet and at 5-foot intervals below this depth. Standard penetration tests (SPTs) were conducted at the time of sampling by driving the sampler into the soil a distance of 18 inches using a 140-pound hammer dropped 30 inches. The number of blows required to drive the standard split-spoon sampler the last 12 inches is known as the Standard Penetration Resistance, or SPT N-value. Samples obtained from the borings were placed in airtight jars and returned to our laboratory for further classification and testing. Logs of the borings are provided on Figures 1A through 4A. Each log presents a summary of the various types of materials encountered in the boring and notes the depths at which the materials and/or characteristics of the materials change. To the right of the summary, the numbers and types of samples are indicated. Farther to the right, SPT N-values are shown graphically, along with the natural moisture contents and percent passing the No. 200 sieve, where applicable. The terms and symbols used to describe the materials encountered in the borings are defined in Table 1A and the attached legend. LABORATORY TESTING General The samples obtained from the borings were examined in our laboratory, where the physical characteristics of the samples were noted and the field classifications modified where necessary. At the time of classification, the natural moisture content of each sample was determined. Additional testing included grain-size analyses. A summary of the laboratory test results is provided in Table 2A. The following sections describe the testing program in more detail. GRI PN#5970-M -Twality Middle School Track and Field Light Poles Page A-1 April 23, 2021 GRO Natural Moisture Content Natural moisture content determinations were made in conformance with ASTM International D2216.The results are summarized on Figures 1A through 4A and in Table 2A. Grain-Size Analysis Washed-Sieve Method To assist in classification of the soils, samples of known dry weight were washed over a No. 200 sieve.The material retained on the sieve was oven-dried and weighed.The percentage of material passing the No. 200 sieve was then calculated.The results are summarized on Figures 1 A through 4A and in Table 2A. GRI PN#5970-M—Twality Middle School Track and Field Light Poles Page A-2 April 23, 2021 GRO Table 1A GUIDELINES FOR CLASSIFICATION OF SOIL Description of Relative Density for Granular Soil Standard Penetration Resistance, Relative Density (N-values) blows/ft Very Loose 0-4 Loose 4- 10 Medium Dense 10-30 Dense 30-50 Very Dense over 50 Description of Consistency for Fine-Grained (Cohesive) Soils Standard Penetration Torvane or Resistance(N-values), Undrained Shear Consistency blows/ft Strength,tsf Very Soft 0- 2 less than 0.125 Soft 2-4 0.125 -0.25 Medium Stiff 4- 8 0.25 - 0.50 Stiff 8- 15 0.50- 1.0 Very Stiff 15 - 30 1.0-2.0 Hard over 30 over 2.0 Grain-Size Classification Modifier for Subclassification Boulders: Primary Constituent Primary Constituent >12 in. SAND or GRAVEL SILT or CLAY Cobbles: Adjective Percentage of Other Material(By Weight) 3-12 in. trace: 5- 15 (sand, gravel) 5- 15(sand, gravel) Gravel: 1/4 -3/4 in.(fine) some: 15 - 30(sand,gravel) 15-30(sand, gravel) 3/4 - 3 in. (coarse) sandy,gravelly: 30- 50(sand,gravel) 30 - 50(sand, gravel) Sand: No.200 - No.40 sieve(fine) trace: <5 (silt,clay) Relationship of clay No.40- No. 10 sieve(medium) some: 5- 12 (silt, clay) and silt determined by No. 10- No.4 sieve(coarse) plasticity index test silty,clayey: 12-50(silt,clay) Silt/Clay: Pass No.200 sieve GRI PN#5970-M—Twality Middle School Track and Field Light Poles April 23,2021 Table 2A SUMMARY OF LABORATORY RESULTS Sample Information Atterberq Limits Moisture Dry Unit Liquid Plasticity Fines Location Sample Depth,ft Elevation,ft Content,% Weight, pcf Limit,% Index,% Content,% Soil Type B-1 5-1 2.5 -- 23 -- -- -- -- Sandy SILT S-2 5.0 -- 30 -- -- -- 51 Sandy SILT S-3 7.5 -- 31 -- -- -- -- Silty SAND S-4 10.0 -- 28 -- -- -- 42 Silty SAND S-5 12.5 -- 21 -- -- -- -- Silty SAND S-6 15.0 -- 22 -- -- -- -- Silty SAND S-7 20.0 -- 27 -- -- -- 59 Sandy SILT 8-2 S-1 2.5 -- 31 -- -- -- -- Sandy SILT S-2 5.0 -- 27 -- -- -- -- Sandy SILT S-3 7.5 -- 28 -- -- -- 43 Silty SAND S-4 10.0 -- 21 -- -- -- -- Silty SAND 1 S-5 12.5 -- 22 -- -- -- -- Silty SAND S-6 15.0 -- 22 -- -- -- 36 Silty SAND S-7 20.0 -- 28 -- -- -- -- Silty SAND B-3 S-1 2.5 -- 24 -- -- -- 50 FILL S-2 5.0 -- 29 -- -- -- -- FILL S-3 7.5 -- 24 -- -- -- -- FILL S-4 10.0 -- 21 -- -- -- -- Silty SAND 5-5 12.5 -- 24 -- -- -- 36 Silty SAND S-6 15.0 -- 24 -- -- -- 38 Silty SAND ! S-7 20.0 -- 20 -- -- -- -- Silty SAND 1 B-4 S-2 5.0 -- 27 -- -- -- 56 FILL S-3 7.5 -- 23 -- -- -- 54 FILL S-4 10.0 -- 25 -- -- -- -- Sandy SILT 5-5 12.5 -- 24 -- -- -- 51 Sandy SILT S-6 15.0 -- 27 -- -- -- -- Silty SAND S-7 20.0 -- 23 -- -- -- 22 Silty SAND G1 `g Page 1 of 1 BORING AND TEST PIT LOG LEGEND SOIL SYMBOLS SAMPLER SYMBOLS Symbol Typical Description Symbol Sampler Description > ;a 2.0 in.O.D.split-spoon sampler and Standard LANDSCAPE MATERIALS I Penetration Test with recovery(ASTM D1586) FILL I. Shelby tube sampler with recovery (ASTM D1587) p GRAVEL;clean to some silt,clay,and sand 11 3.0 in.O.D.split-spoon sampler with recovery (ASTM D3550) ,: Sandy GRAVEL;clean to some silt and clay El Grab Sample ISilty GRAVEL;up to some clay and sand Rock core sample interval AClayey GRAVEL;up to some silt and sand 1 Sonic core sample interval :�xi.;•. SAND;clean to some silt,clay,and gravel Push probe sample interval El Gravelly SAND;clean to some silt and clay INSTALLATION SYMBOLS ftSilty SAND;up to some clay and gravel Symbol Symbol Description Clayey SAND;up to some silt and gravel EtFlush-mount monument set in concrete ® SILT;up to some clay,sand,and gravel I Concrete,well casing shown where applicable III claysa nd SILT;up to some and sa d ' Bentonite seal,well casing shown if applicable Sandy SILT;up to some clay and gravel _ Filter pack,machine-slotted well casing shown where applicable i PIP Clayey SILT;up to some sand and gravel I applicable Grout, vibrating-wire transducer cable shown where ® CLAY;up to some silt,sand,and gravel • Vibrating-wire pressure transducer rfi Gravelly CLAY;up to some silt and sand I 1-in.-diameter solid PVC Sandy CLAY;up to some silt and gravel 1-in.-diameter hand-slotted PVC WISilty CLAY;up to some sand and gravel Grout,inclinometer casing shown where applicable w nr PEAT FIELD MEASUREMENTS BEDROCK SYMBOLS Symbol Typical Description Symbol Typical Description a Groundwater level during drilling and date c measured +++ BASALT t Groundwater level after drilling and date 1- measured a LLI MUDSTONE j Rock/sonic core or push probe recovery(%) w = SILTSTONE Rock quality designation(RQD,%) U o SANDSTONE a U' z SURFACE MATERIAL SYMBOLS w a Symbol Typical Description a a ■ Asphalt concrete PAVEMENT W ■ Portland cement concrete PAVEMENT a z Z m Crushed rock BASE COURSE 0 m It ♦ BLOWS PER FOOT p CLASSIFICATION OF MATERIAL S o a z • MOISTURE CONTENT,% - - — 3 w o ❑ FINES CONTENT,% a i_ ¢ a a �r LIQUID LIMIT,% COMMENTS AND rL 2 a_ o PLASTIC LIMIT,% ADDITIONAL TESTS o o Surface Elevation:Not Available o z CO CO m 0 50 100 Sandy SILT,brown,soft,fine-to medium-grained —. • sand,3-to 6-inch-thick heavily-rooted zone at ground surface • t . s-t 1 ii 1 —mottled rust at 5.0 ft 0 3 1 S2 ❑ 2 I_ 1 . — Silty SAND,brawn,loose to medium dense,fine-to 75 T 2 9 I medium-grained sand s 3 1 5 V 10-7- . 3 10 I " S-4 1 4 . 6 S-5 I3 10 5 • 4 5 I tt 15- S-6 1 6 t♦ ! 4 I _ si ;.i — I 20-1" 20.0 2 9� I Sandy SILT,trace clay,brown,stiff,fine-to sa T 3 —.•. medium-grained sand i 6 p — (4/9/2021) 21.5 25— ' N N Q — ❑ — 0 ui F — m 30— u, r r E w 61 p , •• 35— m a C7 — CD O — O z — E O rn — E cI—40 0 0.5 1.0 Logged By:T.Wilcox Drilled by:Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF Date Started:4/9/21 GPS Coordinates: 45.4145642'N -122.7739166°W(WGS 84) ■ UNDRAINED SHEAR STRENGTH,TSF Drilling Method: Mud Rotary Hammer Type:Auto Hammer Equipment: Geoprobe 7822 DT Weight:140 lb G R I BORING B-1 Hole Diameter. 4 in. Drop:30 in. I Note:See Legend for Explanation of Symbds Energy Ratio: APR.2021 JOB NO.5970-M FIG.1A z w ♦ BLOWS PER FOOT p o CLASSIFICATION OF MATERIAL 2, o n- z • MOISTURE CONTENT,°k LL v g w o ❑ FINES CONTENT,% 1- i ,_ ¢ a a j--r LIQUID LIMIT,% COMMENTS AND as L a a o PLASTIC LIMIT,% ADDITIONAL TESTS o co Surface Elevation:Not Available 0 ? co co co 0 60 100 Sandy SILT,trace clay,very soft to soft,brown,fine- -. to medium-grained sand,3-to 6-inch-thick heavily-rooted zone at ground surface . . . oa S-1I 0 ♦ . _ 0 r t 1 02 - • S-2 I 0 IF 2 I — 1 z5 Si — ?. Silty SAND,trace clay,brown,loose,fine-to s a T 4 —e ♦ L medium-grained sand 1 4 10— : 3 _14 1 —medium dense below 10.0 ft T 7 j i T 7 1. .y:fir:: .. S5 I 3 7 _14 7 I 1 . . . 15— `. _: --loose 2 _;.:.....•:.-.: S-6 I 2 4 ❑ 5 1 I 20—: i 2 g 1 21.5 4 — (419/2021) 25— I ' N — h V _ 1— a — 05 W F - m 30— w re W — Q , . 35— F) a a U' z — Q it (5-40 D 0.5 1.0 Logged By:T.Wilcox Drilled by:Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF • Date Started:4/9/21 GPS Coordinates: 45.4137275°N -122.7744635°W(WGS 81) UNDRAINED SHEAR STRENGTH,TSF Drilling Method: Mud Rotary Hammer Type:Auto Hammer Equipment: Gecprobe 7822 DT Weight:140 lb G R D Hole Diameter. 4 in. Drop:30 in. BORING B-2 Note:See Legend for Explanation of Symbols Energy Ratio: APR.2021 JOB NO.5970-M FIG.2A V N. z w A BLOWS PER FOOT O CLASSIFICATION OF MATERIAL o o a z • MOISTURE CONTENT,% u- v 1- g W LIJ o ❑ FINES CONTENT, J J J C) trLIQUID LIMIT,% COMMENTS AND a d w (r) ¢ ¢ o PLASTIC LIMIT,% ADDITIONAL TESTS o o Surface Elevation:Not Available o z co co in 0 50 100 w l Asphalt concrete PAVEMENT(4 in.)over crushed t rock BASE COURSE(8 in.) / 1.0 Silty SAND to sandy SILT,trace clay,brown mottled gray,very loose to loose,to very soft to medium stiff, 2 5 fine-to medium-grained sand(Fill) s-1 I 3 ♦ AO 0 2 S-2I04T • 2 I 5-3I 14 10 ;. °. SiltySAND,trace day,yellow-brown,loose,fine-to 10.0 4 7 I — > medium-grained sand 4 . •' _ 1 —brown below 12.5 ft 2 7 L S-5 1 3 • ❑ 4 15—. 3 6 S-6 13 . + D . . 3 I , _ I 20—.:.!: 7 —yellow-brown at 20.0 ft 3 + S-7 I 4 A 21.5 3 _ - (4/9/2021) - - 25— N — . . h V a a LU I- — J — • 30 w . . a a s o — w — O Z 35- m . a c� — J O 1111 K m _ "-40 0 0.5 1.0 Logged By:T.Wlcox Drilled by:Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF Date Started:4/9121 GPS Coordinates: 45.4143107°N -122.7730379°W(WGS 84) ■ UNDRAINED SHEAR STRENGTH,TSF Drilling Method: Mud Rotary Hammer Type:Auto Hammer Equipment: 4 7822 DT Weight:Drop 130 in. BORING B-3 Hole Diameter. 4 in. Drop:30 in. Note:See Legend for Explanation of Symbds Energy Ratio: APR.2021 JOB NO.5970-M FIG.3A z w A BLOWS PER FOOT CLASSIFICATION OF MATERIAL o a ~ 0 o z • MOISTURE CONTENT,% LL 0 LL S w w o 0 FINES CONTENT,% 52 5 1--1—LIQUID LIMIT,% COMMENTS AND d Lu u¢', a a o PLASTIC LIMIT,% ADDITIONAL TESTS 0 co Surface Elevation:Nat Available 0 z a) co m 0 50 100 o� Asphalt Concrete PAVEMENT(4 in.)over crushed — .,,3,.,:1 rock BASE COURSE(8 in.) 11A • GRAVEL,trace sand,gray,loose,subrounded to subangular(Fill) 3 s S-1I 2 3 °:: Sandy SILT,trace to some day,brown mottled gray, 5'0 2 "' medium stiff,fine-to medium-grained sand(Fill) S-2 4 Q —soft to medium stiff at7.5ff 1 4 I .::::I. ° S-3 I 8 • ❑. _ . I 10 '••' Sandy SILT,trace to some clay,yellow-brown,stiff, 10'0 3 _10 —. fine-to medium-grained sand s4 s f --mottled gray,very stiff at 12.5 ft ss I s 1I a 0 s Wi 15t. . 15.0 Silty SAND,yellow brown,loose,fine-to T 3 e — i medium-grained sand �0 1 4 ' ' t t 20 ` ' —loose to medium dense at 20.0 ft 3 10 1 5-7 15 . 21.5 5 — (4/912021) 1 i , 25— i Cl L. -4- — ❑ — . a w r — m 30— 1 w r o w _ w _ 35— F a p _ J c z — c7 o an _ re c5—40 0 0.5 1.0 Logged By:T.Wlcox Drilled by:Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF Date Started:4/9/21 GPS Coordinates: 45.4135244°N -122.7736115°W(WGS 81) • UNDRAINED SHEAR STRENGTH,TSF Drilling Method: Mud Rotary Hammer Type:Auto Hammer Equipment: Geoprobe 7822 DT Weight:140 lb GR Hole Diameter. 4 in. Drop:30 in. BORING B-4 Note:See Legend for Explanation of Symbols Energy Ratio: APR.2021 JOB NO.5970-M FIG.4A