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RECEIVED KL EIIVEEL DER P?©(- - FEB 2 3 2015 Bright People.Right Solutions. City of Tigard CITY OF TIGARD City DIVISION A•.:rove. Plans February 28, 2011 ByA .& Date Kleinfelder Project No.: 115042 ��jQ Costco Wholesale OFFICE COPY 999 Lake Drive Issaquah, WA 98027 Attn: Mr. David Rodgers, Director of Real Estate Development Subject: Geotechnical Engineering Report Proposed Costco Wholesale Fuel Facility Costco Wholesale Warehouse #111 7855 SW Dartmouth Avenue Tigard, OR 97006 Costco Wholesale Project No. CW-10-0306-03 MulvannyG2 Project No. 10-0322-03 Dear David: This letter transmits one electronic copy (portable document format) of our geotechnical engineering report for the proposed fuel facility addition at the Costco Wholesale Warehouse in Tigard, Oregon. This report was prepared in accordance with our proposal dated December 15, 2010. We appreciate the opportunity to provide geotechnical services to you on this project. Please contact the undersigned at (425) 636-7900 if you have any questions regarding this report, or if we can provide assistance with other aspects of the project. Sincerely, KLEINFELDER �Gtt� Marcus B. Byers, P.E. Senior Geotechnical Engineer Geotechnical Group Manager Attachment: February 28, 2011, Geotechnical Engineering Report 115042/POR11 R021 February 28, 2011 Copyright 2010 Kleinfelder 9200 SW Nimbus Ave., Suite A, Portland, OR 97008 p i 503.644.9447 f 1 503.643.1905 KL E/NPEL DER Bright P.,,, Prepared for: Costco Wholesale 999 Lake Drive Issaquah, WA 98027 Geotechnical Engineering Report Proposed Costco Fuel Facility Costco Wholesale Warehouse #111 7855 SW Dartmouth Avenue Tigard, OR 97006 Costco Wholesale CW-10-0306-03 MulvannyG2 Project No. 10-0322-03 Prepared by: ��- pR°/;:c ev 53850PE OREGON 0, ��qAY ,5•,�0 RSA N wH\.�� .01.4 V40444 kNEY(Al DATE: 461-S0/2-4 t 2-1 Mark Swank, R.G., C.E.G. Ryan White, P.E., G.E. Engineering Geologist Geotechnical Engineer KLEINFELDER WEST, INC. 14710 NE 87th Street Suite 100 Redmond, WA 98052 Phone: (425) 636-7900 Fax: (425) 636-7901 February 28, 2011 Kleinfelder Project No. 115042 Copyright 2011 Kleinfelder All Rights Reserved This document was prepared for use only by the client,only for the purposes stated,and within a reasonable time from issuance. Non-commercial,educational and scientific use of this report by regulatory agencies is regarded as a fair use and not a violation of copyright. Regulatory agencies may make additional copies of this document for internal use.Copies may also be made available to the public as required by law.The reprint must acknowledge the copyright and indicate that permission to reprint has been received. 11 5042/POR11 R021 Page i of iii February 28, 2011 Copyright 2011 Kleinfelder 1 KL EINFELDER Hiiyh. Right Sotut.,n TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY 1 1.0 INTRODUCTION AND SCOPE 2 1.1 GENERAL 2 1.2 PROJECT DESCRIPTION 2 1.3 AUTHORIZATION AND SCOPE OF SERVICES 2 2.0 SITE EXPLORATION AND LABORATORY TESTING 4 2.1 SITE EXPLORATION 4 2.2 LABORATORY TESTING 4 2.3 ANALYTICAL TESTING 4 2.3.1 Corrosion Potential 4 3.0 SITE CONDITIONS 6 3.1 SURFACE CONDITIONS 6 3.2 GENERAL GEOLOGIC CONDITIONS 6 3.3 SUBSURFACE CONDITIONS 6 3.4 GROUNDWATER CONDITIONS 7 4.0 DESIGN RECOMMENDATIONS 8 4.1 FOUNDATION SUPPORT 8 4.2 SEISMIC DESIGN CONSIDERATIONS 8 4.2.1 Seismic Hazards 8 4.2.2 IBC Seismic Design Criteria 9 4.3 ASPHALT AND PORTLAND CEMENT CONCRETE PAVEMENTS 9 4.3.1 Design Assumptions 9 4.3.2 Asphalt Concrete Pavement 10 4.3.3 Asphalt Performance Grade Binder 10 4.3.4 Portland Cement Concrete Pavement 11 4.3.5 Pavement Drains 11 5.0 CONSTRUCTION RECOMMENDATIONS 12 5.1 EARTHWORK 12 5.1.1 Excavation 12 5.1.2 Clearing, Grubbing and Demolition 12 5.1.4 Subgrade Preparation 13 5.1.5 Weather Considerations 13 5.2 STRUCTURAL FILL MATERIALS AND COMPACTION 13 5.3 TEMPORARY EXCAVATIONS AND SLOPES 14 5.4 UTILITY TRENCHES AND EXCAVATIONS 15 6.0 ADDITIONAL SERVICES 16 7.0 LIMITATIONS 17 8.0 REFERENCES 19 115042/POR11 R021 Page ii of iii February 28, 2011 Copyright 2011 Kleinfelder KL E/NFEL DER LIST OF FIGURES FOLLOWING TEXT Figure 1 — Site Location Map Figure 2 — Site Plan LIST OF APPENDICES Appendix A Field Exploration Appendix B Geotechnical Laboratory Testing Appendix C Important Information About Your Geotechnical Engineering Report 1 15042/POR11 R021 Page iii of iii February 28, 2011 Copyright 2011 Kleinfelder KLE/NFELDER &yh[VeoPle Might Solutions EXECUTIVE SUMMARY PROPOSED FUEL FACILITY ADDITION COSTCO WHOLESALE WAREHOUSE #111 TIGARD, OREGON This project involves construction of a new fuel facility at the Tigard Costco Wholesale Warehouse at 7855 SW Dartmouth Avenue in Tigard, Oregon. The facility will consist of three service islands, with three pumps each, a canopy, a kiosk, three 20,000-gallon underground storage tanks (USTs), and one 1,500 gallon Fuel Additive Tank. The USTs will be installed to a maximum depth of 20 feet below the pavement surface. Based on the results of our subsurface exploration and engineering analyses, it is our opinion that the currently proposed location is suitable for the planned development. The following items are key conclusions developed from our study. • Shallow spread footings are appropriate for supporting the planned canopy and fuel islands. • The site is underlain by silt and clay with variable amounts of fine sand. These soils are moisture sensitive and will only be suitable for re-use during dry weather, and may require drying, which is typically not practical at an operational warehouse site. We recommend the contract documents include a unit cost and provision for import of granular structural fill and export of on-site soil. • Performance Grade binder (PG) 64-16 appropriate for the project. • UST excavations will be on the order of 20 feet deep. Groundwater is expected to be present at a depth of approximately 6 1/2 feet and construction dewatering will likely be required. 1 15042/POR1 1 R021 Page 1 of 19 February 28, 2011 Copyright 2011 Kleinfelder LK E/NFEL DER 1.0 INTRODUCTION AND SCOPE 1.1 GENERAL This report presents the results of Kleinfelder's geotechnical engineering study for the design and construction of the proposed fuel facility addition at the Costco Wholesale Warehouse in Tigard, Oregon. The project site is located at 7855 SW Dartmouth Avenue as shown on the Site Location Map, Figure 1. 1.2 PROJECT DESCRIPTION Our understanding of the project is based on conversations with and information provided by David Segal of Barghausen Consulting Engineers, Inc (Barghausen). We understand the project involves constructing a fuel facility at the northeast corner of the site in a portion of the current parking lot, as shown on the Site Plan, Figure 2. The fuel facility will consist of three service islands with a canopy, a kiosk, three 20,000-gallon underground storage tanks (USTs), and one 1,500 Fuel Additive Tank. The USTs will be installed to a maximum depth of 20 feet below the pavement surface. 1.3 AUTHORIZATION AND SCOPE OF SERVICES The purpose of our study was to explore subsurface conditions at the site and provide geotechnical recommendations for design and construction of the proposed fuel facility addition. Our scope of services was consistent with that presented in our proposal dated December 15, 2010, and included: • Field Exploration: Soil and groundwater conditions at the site were explored with four borings. Two borings were advanced to a depth of 41.5 feet within in the footprint of the proposed UST excavations. One of these borings was completed as a 2-inch groundwater monitoring well. Two borings were advanced to a depth of 11.5 feet in the vicinity of the proposed canopy foundations. • Laboratory Testing: Geotechnical laboratory testing included natural moisture content tests, Atterberg limits tests, percent fines, pH and resistivity tests, chloride content, and sulfate/total sulfides content. • Geotechnical Analysis: Engineering analyses were performed as the basis for developing geotechnical design and construction recommendations. 115042/POR11 R021 Page 2 of 19 February 28, 2011 Copyright 2011 Kleinfelder KLEINFELOER (Moto People Right solutions • Geotechnical Report: The results of our study are presented in this geotechnical engineering report. 115042/POR11 R021 Page 3 of 19 February 28, 2011 Copyright 2011 Kleinfelder 1 KLE/NFELDER Bright People.Filth,SOlutiotn. 2.0 SITE EXPLORATION AND LABORATORY TESTING 2.1 SITE EXPLORATION The field exploration program was performed on January 10, 2011, under full-time observation of a Kleinfelder geologist and consisted of advancing four borings (designated B-1 through B-4). Borings B-1 and B-2 were advanced to a depth of 41 .5 feet within in the footprint of the proposed UST excavations utilizing mud rotary drilling techniques. A flush mounted 2-inch monitoring well was installed in boring B-1. Borings B-3 and B-4 were advanced to a depth of 11.5 feet in the vicinity of the proposed canopy foundations utilizing hollow-stem auger drilling techniques. Boring locations are shown on the Site Plan, Figure 2. Explorations were located by measuring distances from existing features and are considered approximate. Additional information on the site exploration program including summary borings logs are presented in Appendix A. 2.2 LABORATORY TESTING Laboratory tests were performed on select soil samples in general accordance with ASTM standards to determine index and engineering properties. Tests included 16 natural moisture contents, 2 Atterberg limits tests, and 2 US No. 200 standard sieve washes (percent fines). The laboratory program also included two corrosivity suites, which include testing pH, resistivity, chloride content, and sulfate/total sulfides content. Laboratory test results are presented on the boring logs in Appendix A and/or in Appendix B. 2.3 ANALYTICAL TESTING 2.3.1 Corrosion Potential Selected samples of the on-site soils encountered were subjected to chemical analysis for the purpose of preliminary corrosion assessment. The samples were tested for pH, resistivity, soluble sulfates and soluble chlorides. The samples were tested in general accordance with EPA methods for pH, soil box resistivity, soluble chlorides, and soluble sulfates. The test results are presented below in the Table 1 , Summary of Corrosion Test Results. 1 15042/POR1 1 R021 Page 4 of 19 February 28, 2011 Copyright 2011 Kleinfelder KL E/NFEL DER &rght People Pight Soluttom Table 1: Summary of Corrosion Test Results Boring Depth pH Sulfate Chloride Resistivity (ft) (Ppm) (ppm) (ohm-cm) B-1 5 - 6.5 6.4 64.9 ND 1 ,600 B-4 5 - 6.5 6.7 ND ND 2,800 ppm de no es pars per mi ion ND-Not Detected Table 2: Corrosivity Classification Resistivity (ohms cm) Corrosivity Category 0 to 1 ,000 Severely corrosive 1 ,000 to 2,000 Corrosive 2,000 to 10,000 Moderately corrosive greater than 10,000 Mildly Corrosive Based on the resistivity results of 2,800 and 1,600 ohms-cm, the soil is expected to be moderately corrosive to corrosive. We recommend that all concrete in contact with the on-site soils contain Type II cement and be placed in accordance with ACI procedures. Type II cement is commonly used throughout the Pacific Northwest. Based on discussions with Barghausen Consulting Engineers, we understand that the underground fuel system components are corrosion resistant and that no unusual measures related to corrosivity are required for the project. 115042/POR1 1 R021 Page 5 of 19 February 28, 2011 Copyright 2011 Kleinfelder I KL E/NFEL DER \�'8,fight P.,pie Righr SSWI0,s 3.0 SITE CONDITIONS 3.1 SURFACE CONDITIONS The proposed fuel facility addition is located in the northeast corner of the existing asphalt surfaced warehouse parking lot. The lot is relatively level with a gentle slope down to the south. The pavement is generally in poor to good condition with some fatigue cracking and rutting observed. Several asphalt patches were observed where the pavement had been repaired. A pavement evaluation was not in our scope of work. We understand that information on past pavement repair projects at the site will be provided to Kleinfelder for review prior to finalization of this report. Detailed site survey information was not available at the time of this report. 3.2 GENERAL GEOLOGIC CONDITIONS Schlicker and Deacon map the site geology as Quaternary Willamette Silt In Engineering Geology of the Tualatin Valley Region (1967). Quaternary Willamette Silt is characterized as bedded silt and fine sand with occasional clay, lenses of pebbly, fine- to medium-grained sand, with locally scattered granite and quartzite cobbles. The unit is approximately 50 feet thick near the center of the Tualatin Valley and thins toward the valley margins. 3.3 SUBSURFACE CONDITIONS Subsurface conditions encountered in our borings included fill over Willamette Silt deposits, which extended to the depths explored. The units are described in the order encountered as follows: Pavement Section: Our borings encountered approximately 3 inches of asphalt pavement and between 4 and 8 inches of aggregate base. The aggregate base was gravel with sand, with N60-values between 7 and 9 blows per foot. Fill: Approximately 4 to 6 feet of fill consisting of clay, sandy clay, silt or silt with sand underlies the pavement section. The consistency of the cohesive clay, sandy clay, and silt was generally medium stiff to stiff, with N60-values between 6 and 13 blows per foot. The relative density of silt with sand was medium dense, with a N60-value of 16 blows per foot. 115042/POR1 1 R021 Page 6 of 19 February 28, 2011 Copyright 2011 Kleinfelder KLE/NFELDER \�/&iyhi Grr,fr Riyht Sor„r. The moisture contents of the clay, sandy clay, and silt were about 30 percent and plasticies were typically low to medium. Willamette Silt: Willamette Silt deposits were encountered beneath the fill in all borings and extended to the total depths explored. Willamette Silt deposits consist of interbedded clay, silt, silt with sand, and silty sand. The consistency of the cohesive clay, sandy clay, and silt was medium stiff to hard, with N60-values between 9 and 52 blows per foot. The relative density of the silt with sand was medium dense to dense, with N60-values of 16 and 29 blows per foot. The blow counts generally increased with depth. Clay, sandy clay, and silt moisture contents were generally between 25 and 45 percent and plasticity ranged from low to high. 3.4 GROUNDWATER CONDITIONS Mud rotary drilling techniques typically obscure the actual depth to groundwater due to the addition of fluids during advancement of the boring. Therefore, groundwater level measurements could not be directly measured using these techniques. A 2-inch piezometer was installed in boring B-1 and measured at 7 feet below top of casing on January 19, 2011 , about one week after installation, and 6 1/2 feet on February 28, 2011 . It should be noted that fluctuations in groundwater level could occur due to variations in rainfall, pumping from wells, utility trench locations and depths, and other factors that were not evident at the time of our investigation. If significant variations in groundwater levels are encountered during construction, it may be necessary for Kleinfelder to review our recommendations presented herein and adjust them as necessary. 1 15042/POR1 1 R021 Page 7 of 19 February 28, 2011 Copyright 2011 Kleinfelder • LK EIA'FELDER Bright People.Night Solution 4.0 DESIGN RECOMMENDATIONS 4.1 FOUNDATION SUPPORT Based on the relatively light loads imposed by the planned fuel islands and canopy, it is our opinion that conventional shallow spread footings founded on properly prepared subgrade are appropriate. We understand that uplift loads often control canopy footing sizes. Therefore, footings should be proportioned for a nominal allowable bearing pressure of 2,000 psf with an allowance for a 1/3 increase in bearing pressure for transient loading conditions such as wind and seismic loads. All footings should be founded at least 18 inches below the lowest adjacent finished exterior grade to provide frost protection. Continuous strip footings should have a minimum width of 2 feet and isolated column footings a minimum width of 3 feet. We estimate that settlement of foundations bearing on properly prepared subgrade will be on the order of one inch or less. Lateral loads can be resisted by an allowable passive pressure against buried portions of the footings equal to that generated by a fluid with an equivalent unit weight of 350 pcf in the fill soil. Sliding resistance between subgrade soils and foundations cast directly on the soil can be evaluated by an allowable coefficient of friction of 0.35. If footings are poured on a minimum 4 inches of compacted crushed rock, then the ultimate coefficient of friction may be increased to 0.50. These values include factors of safety of 2.0 and 1.5 for evaluating passive and sliding resistance, respectively. 4.2 SEISMIC DESIGN CONSIDERATIONS 4.2.1 Seismic Hazards The Canby-Molalla fault is mapped within 1.5 miles of the site and the latest identified movement of this fault is less than 15,000 years ago, which means it is considered to be active. The soil liquefaction hazard at the site is rated high by the generalized map prepared by Oregon Department of Geology and Mineral Industries (DOGAMI). However, our assessment of the liquefaction hazards indicates the potential at the site is low. Soils in the upper approximately 20 feet of the site are generally low to medium plasticity silt to clayey silt. Because the consistency of the soil in the upper 20 feet is 115042/POR11 R021 Page 8 of 19 February 28, 2011 Copyright 2011 Kleinfelder KLE/NFEL DER generally medium stiff to stiff and the plasticity index is generally greater than 12, it is our opinion that the liquefaction hazard for the shallow site soils is low. While liquefaction could occur in isolated layers of granular soils below this depth, it is our opinion that this would not result in a loss of bearing capacity for the canopy footings or present a significant life-safety hazard beyond that due to strong earth shaking associated with the design-level earthquake. 4.2.2 IBC Seismic Design Criteria In accordance with Section 1615 of the 2009-IBC and based on the results of the explorations performed at the site, we recommend use of Site Class of D. 4.3 ASPHALT AND PORTLAND CEMENT CONCRETE PAVEMENTS 4.3.1 Design Assumptions We understand that pavements in the gas station expansion area will consist of heavy duty flexible asphalt and rigid Portland Cement Concrete pavements. Pavement design recommendations were developed using the following traffic loading assumptions provided in the Costco development guidelines as well as site-specific design parameters and our experience on the prior pavement study and recent pavement reconstruction at the site: • A pavement design life of 20 years; • Standard duty pavement will be subject to 6,600 passenger vehicle trips per year (Traffic Index of 5.0); and • Heavy duty pavements will be subject to 30 tractor-trailer truck tips per day (Traffic Index of 7.0). • Subgrade consists of soils with a CBR of 4. • Subgrade will be prepared in accordance with Section 5.1 .4. • Adequate drainage of surface water will be provided. 1 15042/POR1 1 R021 Page 9 of 19 February 28, 2011 Copyright 2011 Kleinfelder 6;LEINFELDER \\ ''Bright People Pigh,Solo,io,n 4.3.2 Asphalt Concrete Pavement Asphalt concrete pavement, also referred to as Hot Mix Asphalt (HMA), was designed in accordance with the Asphalt Institute Manual Series MS-1 . All HWA should be designed, prepared and placed in accordance with the most recent edition of the Costco Wholesale Master Specifications. Heavy Construction traffic on asphalt concrete pavements may exceed the design load and will potentially damage or shorten the life of the pavements. Therefore, we recommend the contractor take appropriate measures to protect the existing and new pavement during construction. The recommended flexible pavement sections are presented in Table 1. Table 3: Recommended Flexible Pavement Sections Layer Thickness (Inches) Component Standard Duty Heavy Duty Hot Mix Asphalt 3 4 Crush Rock Base 8 12 Crush rock base should conform to Oregon Standard Specifications section 02630. If required, imported granular subbase should conform to Oregon Standard Specifications section 00641 .10(b). The thickness of crushed rock base recommended for the flexible pavement sections has been increased based on the thickness of base rock observed on site in our explorations. 4.3.3 Asphalt Performance Grade Binder Performance Grade binder (PG) 64-16 is appropriate for the project. Binder selection was performed in accordance with Costco Wholesale Specifications Section 02741 . Air temperature data for the five data stations nearest the project site was averaged and the PG was selected using the FHWA program LTTPBind Version 3.1. The high-end temperature rating was selected as one grade higher that the 98% reliability binder and the low-end temperature was selected to provide a reliability of at least 90%. 1 15042/POR1 1 R021 Page 10 of 19 February 28, 2011 Copyright 2011 Kleinfelder rKL E/NFEL DER \� l' Bright People.Right So lution, 4.3.4 Portland Cement Concrete Pavement Portland Cement Concrete Pavement (PCC) was designed in accordance with the Portland Cement Association Thickness Design for Concrete Pavements. Prior to placement of PCC, the subgrade should be prepared in accordance with Section 5.1 .4. The recommended rigid pavement sections are presented in Table 2. Table 4: Recommended Rigid Pavement Sections Layer Thickness (Inches) Component — - - - - - Standard Duty ! Heavy Duty PCC 5 6 Crush Rock Base 6 6 Crushed rock base should conform to Oregon Standard Specifications section 02630. If required, imported granular subbase should conform to Oregon Standard Specifications section 00641 .10(b). These pavement sections are applicable for pavements with aggregate interlock joints and edge support. The concrete should possess a minimum modulus of rupture of 600 pounds per square inch (psi) and the mix should be designed in accordance with the PCA manual. We recommend that PCC pavements be reinforced with a welded wire or an approved equivalent. The structural engineer should perform final reinforcement design. Longitudinal and transverse joint spacing should not exceed 12 feet and 15 feet, respectively. Joint details should conform to PCA guidelines. Expansion joints in concrete slabs should be sealed with petroleum resistant sealant to prevent minor releases from impacting subsurface soil. 4.3.5 Pavement Drains Due to the presence of silty / clayey subgrade soils and their relatively poor drainage characteristics, we recommend that radial pavement drains be installed in the area of the proposed new pavements. 115042/POR11 R021 Page 11 of 19 February 28, 2011 Copyright 2011 Kleinfelder LK E/NFEL DER &nthe People.Right Solutions 5.0 CONSTRUCTION RECOMMENDATIONS 5.1 EARTHWORK 5.1.1 Excavation Excavation of the on-site soils can generally be performed with conventional earthmoving equipment such as dozers, scrapers, and excavators. 5.1.2 Clearing, Grubbing and Demolition Prior to site grading existing pavements and curb should be demolished. Irrigation and utility systems should be abandoned in accordance with the Plans and Specifications. Asphalt and concrete pavements can be recycled for use as base course provided they comply with the required gradation specifications. Following demolition, all vegetation and any trash or remaining debris should be removed and properly disposed of offsite. 5.1.3 Shoring and Dewatering It is our understanding that the underground storage tank excavation will extend to a depth of approximately 18 to 20 feet below the existing ground surface. Shoring requirements will be based on work area limitations. We observed groundwater at a depth of approximately 7 feet in the piezometer about one week after completion of our exploration program. Groundwater was measured at a depth of 6 1/2 feet on February 28, 2011 (refer to Section 3.4). Based on this, we anticipate that construction dewatering will be required. Due to the relatively low permeability subsurface materials, seepage may be relatively slow but persistent. However, some areas of significant seepage may be encountered in isolated sand layers that are often present in Willamette Silts. Where dewatering systems are installed, well points may be appropriate. A dewatering plan is the responsibility of the excavation contractor. Shoring and dewatering plans should be submitted to Kleinfelder for review before the system is installed. In addition, the contractor should obtain necessary discharge permits for the pumped water and perform any required water-quality testing. 115042/POR11 R021 Page 12 of 19 February 28, 2011 Copyright 2011 Kleinfelder (17:LEINFELDER edyni P.opi.rt;yn,xm,noo, 5.1.4 Subgrade Preparation After excavations have been completed to the planned subgrade elevations, including footing excavations, and before placing fill, the entire exposed subgrade should be evaluated by a Kleinfelder representative. If appropriate, based on site and excavation constraints, the subgrade should be proof-rolled with two passes of a fully-loaded dump truck or water truck. At a minimum, the subgrade should be evaluated by hand probing. Any soft, yielding or unsuitable areas identified by the Kleinfelder representative should be over-excavated to the depth determined by the geotechnical engineer and replaced with compacted structural fill. Following over-excavation and prior to placement of structural fill, the subgrade should be covered with a woven geotextile fabric such as Mirafi 500X or an approved equivalent. 5.1.5 Weather Considerations The on-site soils generally consist of fine-grained silt and clay that is highly susceptible to moisture. These soils are only suitable for use as structural fill during dry weather and be impractical for use during wet conditions. If major earthwork is planned during the drier summer months, use of imported soils may not be required. However, we recommend that a unit cost for import of granular structural fill and export of on-site soils be included in the contract documents. During wet conditions, the contractor should take measures to protect the exposed subgrade and limit construction traffic. It may be expedient to excavate the subgrade with a tracked excavator working off of the existing pavement, and keep all construction traffic off exposed subgrades. These measures could include, but are not limited to, placing a layer of crushed rock on the exposed subgrade, or covering the exposed subgrade with a plastic tarp. If additional over-excavation is required because the subgrade was not protected, the cost of such additional work should be borne by the contractor. 5.2 STRUCTURAL FILL MATERIALS AND COMPACTION Material placed below structures or pavements should be considered structural fill. Structural fill should consist of well-graded material free of organics or other deleterious material and have a maximum particle size of 6 inches. Subsurface conditions consist 115042/POR11 R021 Page 13 of 19 February 28, 2011 Copyright 2011 Kleinfelder KL E/NFEL DER of silt to clay. These soils will only be suitable for use as structural fill during dry weather and may require either drying or amendment with lime or cement. Imported granular structural fill should angular, crushed gravel conforming to Oregon Standard Specifications section 00641.10(b).and have less than 5 percent passing the No. 200 sieve (wet sieve analysis). Granular soil becomes increasingly sensitive to small changes in moisture content and compaction becomes more difficult to achieve with increasing fines (such as silt and clay). Granular soils containing more than about 5 percent fines cannot be adequately compacted when the water content is significantly greater (or significantly less) than the optimum moisture content. The contractor should submit samples of earthwork materials proposed for use during construction to the geotechnical engineer for evaluation and approval prior to use. Samples should be submitted at least one week prior to their use to allow the contractor to identify alternative sources if the material proves unsatisfactory. Structural fill should be moisture conditioned to within 2 percent of the optimum moisture content prior to compaction and should be placed in maximum 8-inch thick lifts. All structural fill should be compacted to a dense and unyielding condition and to a minimum of 95 percent of the modified Proctor maximum dry density as determined per ASTM D1557. 5.3 TEMPORARY EXCAVATIONS AND SLOPES All excavations and slopes must comply with applicable local, state, and federal safety regulations including the current OSHA Excavation and Trench Safety Standards. Construction site safety is the sole responsibility of the Contractor, who shall also be solely responsible for the means, methods, and sequencing of construction operations. We are providing soil type information solely as a service to our client for planning purposes. Under no circumstances should the information be interpreted to mean that Kleinfelder is assuming responsibility for construction site safety or the Contractor's activities; such responsibility is not being implied and should not be inferred. The existing soils are classified as Type C and excavations in these materials should be inclined no steeper than 1 Y H:1 V per the OSHA technical manual. Heavy construction equipment, building materials, excavated soil, and vehicular traffic should not be 115042/POR11 R021 Page 14 of 19 February 28, 2011 Copyright 2011 Kleinfelder igipiimerz (K1E/NA-ELDER \�'&iyht ieop/e Righ,Solution. allowed near the top of any excavation. Where the stability of adjoining buildings, walls, or other structures is endangered by excavation operations, support systems such as shoring, bracing, or underpinning may be required to provide structural stability and to protect personnel working within the excavation. Earth retention, bracing, or underpinning required for the project (if any) should be designed by a professional engineer registered in the State of Oregon. Excavations below the groundwater table will require flatter slopes or shoring. Temporary excavations and slopes should be protected from the elements by covering with plastic sheeting or some other similar impermeable material. Sheeting sections should overlap by at least 12 inches and be tightly secured with sandbags, tires, staking, or other means to prevent wind from exposing the soils under the sheeting. 5.4 UTILITY TRENCHES AND EXCAVATIONS The contractor should be responsible for the safety of personnel working in utility trenches. We recommend all utility trenches and excavations are supported in accordance with state and federal safety regulations and as discussed in Section 5.3. Trench and excavation backfill should be placed and compacted as described in Section 5.2. Pipe bedding material should conform to the manufacturers' recommendations. Particular care should be taken to make sure bedding or fill material is properly compacted in place to provide adequate support to the pipe. Jetting or flooding is not a substitute for mechanical compaction and should not be allowed. 115042/POR11 R021 Page 15 of 19 February 28, 2011 Copyright 2011 Kleinfelder LK E/NFELOER ``�/Soght People.Right Solutiom 6.0 ADDITIONAL SERVICES The recommendations made in this report are based on the assumption that an adequate program of tests and observations will be made during construction to observe and document compliance. Testing and observations performed during construction should include, but not necessarily be limited to, the following: • Observations and testing during site preparation, earthwork, structural fill, and pavement section placement; • Testing and inspection of concrete and structural steel; and • Consultation as may be required during construction. We further recommend that project plans and specifications be reviewed by Kleinfelder to verify compatibility with our conclusions and recommendations. Also, Kleinfelder retains fully accredited and certified laboratory and inspection personnel, who are available for this project's testing and inspection needs. Information concerning the scope and cost for these services can be obtained from our office. 115042/POR11 R021 Page 16 of 19 February 28, 2011 Copyright 2011 Kleinfelder KL E/NFEL DER \�l dryli Vwi,le Hiynt Sale,i<.ii• 7.0 LIMITATIONS Recommendations contained in this report are based on the field explorations and our understanding of the proposed project. The investigation was performed using a mutually agreed upon scope of services. It is our opinion that this study was a cost-effective method to explore the subject site and evaluate the potential geotechnical concerns. The soils data used in the preparation of this report were obtained from exploratory borings and cone penetration tests completed for this study. It is possible that variations in soil and groundwater conditions exist between the points explored. The nature and extent of these variations may not be evident until construction occurs. If soil or groundwater conditions are encountered at this site that are different from those described in this report, our firm should be immediately notified so that we may make any necessary revisions to our recommendations. In addition, if the scope of the proposed project, locations of facilities, or design building loads change from the descriptions given in this report, our firm should be notified. The scope of our services does not include services related to construction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. This report has been prepared for use in design for development of the subject property by Costco Wholesale and their design consultants in accordance with the generally accepted standards of practice at the time the report was written. No warranty, express or implied, is made. This report may be used only by Costco Wholesale and their design consultants and only for the purposes stated within a reasonable time from its issuance, but in no event should this time exceed 24 months from the date of the report. Land or facility use, site conditions (both on- and off-site), regulations, advances in man's understanding of applied science, and/or other factors may change over time and could materially affect our findings and may require additional work. Therefore, this report should not be relied upon after 24 months from its issue. Kleinfelder should be notified if the project is delayed by more than 24 months from the date of this report so that a review of site 115042/POR11 R021 Page 17 of 19 February 28, 2011 Copyright 2011 Kleinfelder (KLEINFELDER conditions can be made, and recommendations revised if appropriate. Any party other than Costco Wholesale or their design consultants who wishes to use this report, shall notify Kleinfelder of such intended use. Based on the intended use of the report, Kleinfelder may require that additional work be performed and that an updated report be issued. It is the responsibility of Costco Wholesale to see that all parties to the 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. Further guidelines and information on this geotechnical report can be found in the ASFE publication entitled Important Information About Your Geotechnical Engineering Report, which is included for your reference in Appendix C of this report. 1 15042/POR1 1 R021 Page 18 of 19 February 28, 2011 Copyright 2011 Kleinfelder (KLEINFELDEW 8.0 REFERENCES 2006 International Building Code, International Code Council and 2007 State of Oregon Updates. Oregon Standard Specifications for Construction, 2008. Schlicker, H.G., Deacon, R.J., 1967, Engineering geology of the Tualatin Valley region, Oregon: Oregon Dept. Geology and Mineral Industries Bull. 60, 103 p. 1 15042/POR1 1 R021 Page 19 of 19 February 28, 2011 Copyright 2011 Kleinfelder Figures s — iL_ i ` - 2LANDAU SW LANDAU _ \ SW LOCUST— Metzger SW LOCUST d SW LOC� it O uf.P 5W F .r , ��#<'n ' _ J __ $1Y YAPLEL EAF SW OAK ll = ,tl SW aAx SW OAK in ti1.- hhh 1 1 SW NNE -1 'FPI IIR creek k 7'hr> /� z �., •� ��,217 - __-.__ �_._. 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FUEL FACILITY ADDITION Q Q I- N„„..................- FILE NAME: Q Q a www.kleinfelder.com 115042F1 dw 7850 SW DARTMOUTH STREET 9 TIGARD,OREGON V / {%l •M M { w )°a 434' 1 LEGEND, , _ I I �/ .xN B-4 O KLEINFELDER BORING LOCATION ;M a e> hi 'Lull \ I , , , • 1111111I1 ILA ` �� d aeu x * C Ai.. = j r 1 I � I 111 '� �i�� 90 RECEIVING / ffr ■ �, EXIST.TIRE CENTER a y II 11 II .� 'c I H . I II �!� v ��9� 1 D , ,I' o I I I �I I II In ∎� 7I � I I I I \•..A .% / a \ 33,' -1 ' l iI' ' � 1 l l l l l II I1111.11111111 .'l l l l l l /y� y c � . m t ; � _I -�,Pit l l I r► - _ . -- -_ _ _B-1 B 4 • 4 4 i C 4 o -- _ -- -- -- —� — „� T�� �_ I Lam. !-r , � , \ _ — �� -- -- 1 1�0'�_1_ ( , ct V — I B-3 ����►� 1 ' . 1/111/11 U l l ' 1 F_ I I l I l�llll l I l 11�( - ' 1 0 20 SCALE 80 DARTMOUTH ROAD o (in feet) o �' – - 1 INCH = 80 FT. � r-7 . F-vuQRK PROJECT NO. 115042 SITE PLAN DRAWN: 01111 KLEINFELDER CHECK D nK FIGURE '+*��� CHECKED BY: RW TIGARD COSTCO •,.................„ T1 �• FUEL FACILITY ADDITION A FILE NAME: 7850 SW DARTMOUTH STREET L ••^-x»=-,..-=.:-.....--.:J7.--7.----_:.....-=-=^ �++• www.xk�nimaer can 115042F2.dwg TIGARD,OREGON �R y�, Sri� roc +R 2 A' y4. h,.• ,• Appendix A Field Explorations 1JIff KL EINFELDER B"ghl People.B■ghl Solutions APPENDIX A FIELD EXPLORATIONS General Kleinfelder advanced four borings (designated B-1 through B-4) on January 10, 2011 , to evaluate subsurface conditions at the site. The general locations of the explorations are shown on the Site Plan, Figure 2. The following paragraphs discuss the procedures used to advance the borings, collect samples, and other field techniques in detail. Unless otherwise noted, all soil sampling and classification procedures follow local engineering practices in general accordance with relevant ASTM procedures. "General accordance" means that certain local and common drilling and descriptive practices and methodologies have been followed. Borings Drilling: A Kleinfelder (geologist / geotechnical engineer) observed Subsurface Technologies, Inc. of North Plains, Oregon advance four borings, designated B-1 through B-4, to depths of 111/2 to 411/2 feet below ground surface using hollow-stem auger and mud rotary drilling techniques. Borings B-2 through B-4 were abandoned in accordance with Oregon Water Resources Department requirements by backfilling with bentonite chips and capping with asphalt cold patch. A 2-inch groundwater monitoring well was installed in boring B-1 . Kleinfelder located the borings, maintained a log of the subsurface conditions and materials encountered, collected soil samples and visually classified soils encountered in the field. Recorded information included consistency, color, relative moisture, degree of plasticity, and other distinguishing characteristics of the soils. Sampling: A Kleinfelder (geotechnical engineer / geologist) collected representative disturbed samples from the materials encountered in the borings, examined the soil samples and placed them in plastic bags for further examination and physical testing in our laboratory. We obtained disturbed soil samples in the borings at selected depth intervals using a standard two-inch outer diameter (O.D.) split-spoon sampler and sampling procedures prescribed for the Standard Penetration Test (SPT; ASTM 1586). The sampler is driven 115042/POR1 1 R021 Page A-1 February 28, 2011 Copyright 2011 Kleinfelder • KL E/NFELOER tlr.yhr People R!y/rf k>>iitons 18 inches into the soil using a 140-pound hammer dropped 30 inches. The number of blows required to drive the sampler the last 12 inches is defined as the standard penetration resistance (or N-value). The N-value provides a measure of the relative density of granular soils such as sand and gravel, and the consistency of cohesive soils such as silt, clay and clayey silt. N-values obtained with the three-inch sampler are adjusted to correlate to SPT N-values. The SPT at each of the borings was driven using an automatic trip hammer. The automatic trip hammer has a higher efficiency rating than the standard rope and cathead to lift the hammer. As a result the N-values (blow counts) using the automatic trip hammer are lower than the standard NbO-values (i.e., manual hammer and cathead values shown on the boring logs). The efficiency of the manual hammer is typically assumed to be 60 percent and the automatic trip hammer is about 80 percent. Boring Logs Figure A-1 explains information and symbols presented on the boring logs (Figures A-2 through A-5). The logs show the various types of materials encountered and the depths where the materials and/or characteristics of these materials changed, although the changes may be gradual. We show the sample type and identification number, groundwater level, field strength data, and most laboratory results on each log. Material Descriptions We visually classified soil samples in the field, including consistency, color, relative moisture, degree of plasticity, and other distinguishing characteristics of the samples. Afterwards, we observed the samples in the laboratory, performed various standard classification tests, and modified the field classifications where necessary. The terminology used in the soil classifications are defined in Table Al. Groundwater Mud rotary drilling techniques typically obscure the depth to groundwater during boring advancement. Therefore, water level measurements were not obtained in the open boreholes. However, a 2-inch monitoring well was installed in boring B-1. We measured the groundwater in the well at a depth of about 7 feet bgs on January 19, 2011 and at a depth of 6.7 feet on February 28, 2011. 115042/POR11 R021 Page A-2 February 28, 2011 Copyright 2011 Kleinfelder • r:LE/NFELDER th ybr People Rlghr srr.,a,n Groundwater levels can fluctuate due to variations in rainfall, irrigation, pumping from wells, utility trench locations and depths, and other factors that were not evident at the time of our investigation. It may be necessary for Kleinfelder to review our recommendations presented herein and adjust them as necessary. In addition, the depth to groundwater should be anticipated to become shallower during the wet seasons (winter and spring). 115042/POR11 R021 Page A-3 February 28, 2011 Copyright 2011 Kleinfelder yf iMh ila?. • - • Table Al Terminology Used to Describe Soil Soil Descriptions Soils exist in mixtures with varying proportions of components. The predominant soil, i.e., greater than 50 percent based upon total dry weight, is the primary soil type and is capitalized in our log descriptions, e.g., SAND, GRAVEL, SILT or CLAY. Lesser percentages of other constituents in the soil mixture are indicated by use of modifier words in general accordance with the Visual-Manual Procedure (ASTM D2488- 93). "General Accordance" means that certain local and common descriptive practices have been followed. In accordance with ASTM D2488, group symbols (such as GP or CH) are applied on that portion of the soil passing the 3-inch (75mm) sieve based upon visual examination. The following describes the use of soil names and modifying terms used to describe fine-and coarse-grained soils. Fine-Grained Soils (More than 50%fines passing 0.074 mm,#200 sieve) The primary soil type, i.e. SILT or CLAY is designated through visual — manual procedures to evaluate soil toughness, dilatency, dry strength, and plasticity. The following describes the terminology used to describe fine-grained soils, and varies from ASTM 2488 terminology in the use of some common terms Plasticity Plasticity Prima( soil NAME, ad'ective and s mbols _ Description Index (PI) ORGANIC SILT CLAY SILT & CLAY ML & MH CL & CH OL&OH SILT Organic SILT Non-plastic 0 - 3 SILT Organic SILT Low plasticity 4 - 10 Clayey SILT Silty CLAY Organic clayey SILT Medium Plasticity >10—20 Clayey SILT CLAY Organic silty CLAY High Plasticity >20—40 Clayey SILT CLAY Organic CLAY Very Plastic >40 Modifying terms describing secondary constituents, estimated to 5 percent increments, are applied as follows: Description % Composition Trace sand,trace gravel 5%- 10% With sand; with gravel 15% -25% Sandy, or gravelly 30% -45% Borderline Symbols, for example CH/MH, are used where soils are not distinctly in one category or where variable soil units contain more than one soil type. Dual Symbols, for example CL-ML, are used where two symbols are required in accordance with ASTM D2488. Soil Consistency. Consistency terms are applied to fine-grained, plastic soils (i.e., PI >4). Descriptive terms are based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586-84, as follows. Consistency Term SPT N-value Unconfined Compressive Strength Tons/sq.ft. kPa Very soft Less than 2 Less than 0.25 Less than 24 Soft 2 -4 0.25 - 0.5 24 -48 Medium stiff 5 -8 0.5 - 1.0 48—96 Stiff 9- 15 1.0 - 2.0 96— 192 Very stiff 16 - 30 2.0 - 4.0 192 — 383 Hard Over 30 Over 4.0 Over 383 Note: For SILT with low to non-plastic behavior, (i.e., PI <4) a relative density description is applied. Page 1 of 2 TABLE Al Table Al (Continued) Terminology Used to Describe Soil Coarse - Grained Soils (less than 50% fines) Coarse-grained soil descriptions, i.e., SAND or GRAVEL, are based on that portion of materials passing a 3-inch (75mm) sieve. Coarse-grained soil group symbols are applied in accordance with ASTM D2488 based upon the degree of grading, or distribution of grain sizes of the soil. For example, well graded sand containing a wide range of grain sizes is designated SW; poorly graded gravel, GP, contains high percentages of only certain grain sizes. Terms applied to grain sizes follow. Particle Diameter Inches Millimeters Sand (S) 0.003 - 0.19 0.075-4.8 Gravel (G) 0.19 -3.0 4.8 - 75 Additional Constituents Cobble 3.0 - 12 75 - 300 Boulder 12 - 120 300 - 3050 Rock Block >120 >3050 The primary soil type is capitalized, and the amount of fines in the soil are described as indicated by the following examples. Other soil mixtures will provide similar descriptive names. Example: Coarse-Grained Soil Descriptions with Fines 10% fines 5% fines (Dual Symbols) 15% to 45% fines GRAVEL with trace silt: GW or GP GRAVEL with silt, GW-GM Silty GRAVEL: GM SAND with trace clay: SW or SP SAND with clay, SP-SC Silty SAND: SM Additional descriptive terminology applied to coarse-grained soils follow. Coarse-Grained Soil Containing Secondary Constituents Clean < 5% fines With sand or with gravel 15% - 25% sand or gravel Sandy or gravelly 30% - 45% sand or gravel With cobbles; with boulders Any amount cobbles or boulders. Additional terms may be used to describe amount including abundant, scattered. Cobble and boulder deposits may include a description of the matrix soils, as defined above. Relative Density terms are applied to granular, non-plastic soils based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586-84. Relative Density Term SPT N-value Very loose 0 -4 Loose 4 - 10 Medium dense 10 - 30 Dense 30 - 50 Very dense > 50 Page 2 of 2 TABLE Al LOG SYMBOLS ■ - -_- � BULK/BAG SAMPLE SOLID PIPE ∎ - - BACKFILLED WITH CEMENT GROUT ..∎ MODIFIED CALIFORNIA de d amleteAMPLER I OD PIP BACKFILLED WITH BENTONITE MATERIAL l CALIFORNIA SAMPLER SOLID PIPE (3 inch outside diameter) BACKFILLED WITH PEA GRAVEL I STANDARD PENETRATION SLOTTED PIPE SPLIT SPOON SAMPLER BACKFILLED WITH PEA GRAVEL 1,, (2 inch outside diameter) L L{L SHELBY TUBE NO ® BACKFILLED WITH BENTONITE MATERIAL r F: j CONTINUOUS CORE NO PIPE L 1 1 BACKFILLED WITH SAND V WATER LEVEL (level where first encountered) NO PIPE Y. WATER LEVEL == BACKFILLED WITH NATIVE SOIL (level after completion) PERCENT FINER El EXPANSION INDEX -4 THAN THE NO 4 SIEVE (UBC STANDARD 29-2) (ASTM Test Method C 136) COL COLLAPSE POTENTIAL PERCENT FINER N -200 THAN THE NO.200 SIEVE (ASTM Test Method C 117) i UC UNCONFINED COMPRESSION v- (ASTM Test Method D 2166) in LL LIQUID LIMIT (ASTM Test Method D 4318) m MC MOISTURE CONTENT 0 (ASTM Test Method D 2216) w cn w PLASTICITY INDEX w PI (ASTM Test Method D 4318) cc fn GENERAL NOTES w 1.Lines separating strata on the logs represent approximate boundaries only. Actual transitions may be gradual. rc 0 a ce o o 2.No warranty is provided as to the continuity of soil conditions between individual sample locations. 1 oo 3.Logs represent general soil conditions observed at the point of exploration on the date indicated. a 1- w a4.In general, Unified Soil Classification System designations presented on the logs were evaluated by visual methods only. 0 Therefore,actual designations(based on laboratory tests)may vary. a ce 0 U Project Number: 115042 Plate o ��� - LOG KEY O Date: 01-10-11 Y KL E/NFEL DER Entry By: MWS w Bright People.Right Solutions. �-� Checked By: RKW Tigard Costco Fuel Facility Addition File Name: (sheet 1 of 2) z Copynght Kleinfelder.Inc.2007 UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM 2487) MAJOR DIVISIONS GRAPHIC TYPICAL LOG DESCRIPTIONS CLEAN GRAVELS CuN4 and WELL-GRADED GRAVELS,GRAVEL-SAND uCF3 •II GW MIXTURES WITH LITTLE OR NO FINES WITH<5% FINES Cu�4and/or u POORLY-GRADED GRAVELS,GRAVEL-SAND 1>Cc�3 r�'' GP MIXTURES WITH LITTLE OR NO FINES Cuk4 and r''GW-GM WELL-GRADED L MIXTURES DH RA LE FINERAVEL-SAND 1<C3 WELL-GRADED GRAVELS,GRAVEL-SAND GRAVELS GW-GC MIXTURES WITH LITTLE CLAY FINES GRAVELS WITH 5 to 12% i FINES POORLY-GRADED GRAVELS, RAVELSAND (More than half of �� « ' GP-GM MIXTURES W ITH LITTLE FINES Ulan POORLY-GRADED GRAVELS,GRAVEL-SAND is larger coarse 1�c>3 •kit!)% GP-GC MIXTURES WITH LITTLE CLAY FINES the#4 sieve) I1., GM SILTY GRAVELS,GRAVEL-SILT-SAND MIXTURES GRAVELS WITH>12% Pj GC CLAYEY GRAVELS,GRAVEL-SAND-CLAY MIXTURES FINES .t4r, COARSE rat GC-GM CLAYIXTURES EY GRAVELS,GRAVEL-SAND-CLAY-SILT 1 �' M GRAINED — SOILS CLEAN SANDS 1 Cu and SW WEL-GQED SANDS,SAND-GRAVEL MIXTURES WITH LITTLE OR NO FINES (More than half WITH<5% ' ( FINES Cu.6 and/or• .,• POORLY-GRADED SANDS,SAND-GRAVEL MIXTURES of material 1�Cc'3 SP WITH LITTLE ORE NO FINES is larger than the#200 sieve) : SW-SM WELL-GRADED SANDS,SAND-GRAVEL MIXTURES WITH Cu'6 and LITTLE FINES SANDS 1sC3 WELL-GRADED SANDS,SAND-GRAVEL MIXTURES WITH (More than half of SANDS WITH SW-SC LITTLE CLAY FINES coarse fraction 5 to 12%FINES ' S P-SM POORLY-GRADED ED SANDS,SAND-GRAVEL MIXTURES is smaller than Cu<6 and/or '• . the#4 sieve) 1>Cc.3 SP-SC POORLY-GRADED SANDS,SAND-GRAVEL MIXTURES WITH LITTLE CLAY FINES SM SILTY SANDS,SAND-GRAVEL-SILT MIXTURES 0. SANDS W ITH SC CLAYEY SANDS,SAND-GRAVEL-CLAY MIXTURES o g >12%FINES i SC-SM CLAYEY SANDS,SAND-SILT-CLAY MIXTURES m J INORGANIC SILTS AND VERY FINE SANDS,SILTY OR ro ML CLAYEY FINE SANDS,SILTS WITH SLIGHT PLASTICITY, re INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, °° FINE SILTS AND CLAYS CL GRAVELLY CLAYS,SANDY CLAYS,SILTY CLAYS,LEAN E GRAINED CLAYS u) SOILS (Liquid limit less than 50) CL-ML INORGANIC CLAYS-SILTS OF LOW PLASTICITY, i GRAVELLY CLAYS,SANDY CLAYS,SILTY CLAYS,LEAN Co CLAYS re - OL ORGANIC SILTS&ORGANIC SILTY CLAYS OF LOW o PLASTICITY El (More than half INORGANIC SILTS,MICACEOUS OR DIATOMACEOUS FINE Z of material M H w is smaller than SAND OR ANI SILT x the#200 sieve) SILTS AND CLAYS r- CH INORGANIC CLAYS OF HIGH PLASTICITY,FAT CLAYS 0 o (Liquid limit greater than 50) a OH I ORGANIC CLAYS&ORGANIC SILTS OF MEDIUM-TO-HIGH IT PLASTICITY F ¢4 a_ Project Number: 115042 UNIFIED SOIL CLASSIFICATION Plate o � SYSTEM (ASTM D2487) o Date: 01-10-11 KL EINFEL DER Entry By: MWS A-1 co N Bright People.Right Solutions. o \, Checked By: RKW Tigard Costco Fuel Facility Addition �� File Name: (sheet 2 of 2) D, CopyngM IOentelder,Inc.2010 INS :1 s w ti. .-',-.'W.4-707.: -'::;•:'..:.,::..,,,.:',....,.,„,.,',::.. .3. Boring Number:B-1 Location:Tigard,OR Drilling Method:Mud Rotary Boring Total Depth:41.5 ft Coordinates(X/Y,Lat/Long): ft/ ft Drilling Equipment:Diedrich D-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11 /01-10-11 Top of Boring Elevation: Bit SIze/Type:6-inch/Tricone Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point:Top of Casing Depth to Groundwater Initial/Time:7.0 ft/ January 19,2011 Hammer Drop/Weight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater FinaVTime:6.7 ft/ February 28,2011 Angle From Horizontal/Bearing:90° Field Soil Description&Classification Laboratory The report and log key are an integral part of these logs. All data and interpretations in this log are subject to those 1. E. stated explanations and limitations. i ^ ,Q t Fj _ E g m N. - Y sr i i & k J 8 r old Da C t • - t. — s . ; . s o Other Tests c� 8 r�i I 03 d < Description ° �N qS Field Notes i v 4 a a 3 o da a3e it 2 3 inches of ASPHALT CONCRETE J flush mount— CL AGGREGATE BASE:(4 inches) -I F S-1 3 CLAY With Sand(CL):drown,moist MD 4 10 0 2 I �: 22 41 72 gd S-2 3 . FILL 4 . 5 2 �! ML SILT(ML):yellowish brown,moist F Lp 35 I p S-3 3 2-inch diameter- • 4 PVC 6 S-4 8 11 10 6 WILLAMETTE SILT 31 ii S-5 9 a 11 - a. CL CLAY(CL):gray,moist F-H Mp backfilled with m7 bentonite el ¢° 11 COit • S7 15 17 26 r 0 C7 / ML SILT(ML): Np-Lp 7 ( ):gray,moist F-H N w S-8 17 z 22 II le I- O 6 41 ci S-9 8 co w 12 a cc o ¢ o o Project Number: 115042 Plate 1 BORING LOG B-1 Date: 01-10-11 t of 2 0 Z KLE/NFELDER Entry By: MWS A-2 E Bright People.Right Solutions. Checked By: RKW Tigard Costco Fuel Facility Addition o File Name: Boring Number:B-1 Location:Tigard,OR Drilling Method:Mud Rotary Boring Total Depth:41.5 ft Coordinates()UY,LatlLong): ft/ ft Drilling Equipment:Diedrich D-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11 /01-10-11 Top of Boring Elevation: Bit Size/Type:6-inch/Tricone Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point:Top of Casing Depth to Groundwater Initial/Time:7.0 ft/January 19,2011 Hammer Drop/Weight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater FinalTime:6.7 ft/February 28,2011 Angle From HorizontalBearing:90° Field Soil Description&Classification Laboratory The report and log key are an integral part of these logs. t. E All data and interpretations in this log are subject to those , e a c r stated explanations and limitations. e r 4 5 � c c ea ` E m c r E vg i m a %r E. I; o & a 0 to Etc A' g' Zi .. wY `o n a Y . >b z '0 Ed cy Other Tests co I 3 a m w n•— m d m d a Description u Q CO CO 3 c ez Rue Field Notes ; v ML ,SILT(ML):brown,moist H Lp 7 S-10 10 17 WILLAMETTE SILT • - sand 10/80-#•: •. % CH CLAY(CH):reddish brown with gray,moist H Hp 5 j � S-11 9 15 j 0/ • N0.01-inch well screen slot size - Z _ . ._ ML SILT With Sand(ML):dark gray,moist.fine Md Np c? sand to medium sand N • • ar, 4 • • S-12 7 m 7 o e . Y a 1 m F to - —. . H z w 4 ' 43 r• 1 w S-13 6 1.fier z 6 Li ) Y Boring completed at a depth of 41.5 ft below — i- existing site grade. 0 co o — t- co w S cc 0 Project Number: 115042 ' Plate $ \ Date: 01-10-11 BORING LOG B-1 2 of 2 z• ( KLEINFELOER Entry By: MWS A M-2 ccBright People.Right Solutions. Checked By: RKW Tigard Costco Fuel Facility Addition gFile Name: ..>'r ;.te 4, .' -! /4 a - i y, tk .: 'am -;-*::,4i....4.•.0•Boring Number:B-2 Location:Tigard,OR Drilling Method:Mud Rotary Boring Total Depth:41.5 ft Coordinates(XN,LatlLong): ft/ ft Drilling Equipment Diedrich D-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11/01-10-11 Top of Boring Elevation: Bit Size/Type:6-inch/Tricone Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point: Depth to Groundwater Initial/Time: Hammer Drop/Weight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater FinaUTime: Angle From Horizontal/Bearing:90° Field Soil Description&Classification Laboratory aThe report and log key are an integral part of these logs.All data and interpretations in this log are subject to those stated explanations and E.N limitations. Z' C -;',E, C m L 9 .cm.. °E i o� : E c� c E c 3 X > 3 d m e 2:` m m n n _ °-" E is u ' V c c m cy Other Tests n 2 T a' ao and g E E r c m a � � h rn a m d 0 < Description 1,8.. d a 3 3 o as as Field Notes -- 3 inches of ASPHALT CONCRETE , - r CL AGGREGATE BASE:(4 inches) F M CLAY(CL):brown with reddish brown,moist p 2 29 S1 5. FILL 1 S2 4 6 IML SILT(ML):grayish brown,moist F Lp-Mp 3 34 S3 2 5 ML SILT(ML):brown,moist F Lp 10 I 5 - ° S-4 7 a 11 - a. t7 _ N E r 6 WILLAMETTE SILT 32 m S5 8 0 13 rr dI 1 7 o 9 0 y 11 f (7 I - w 5 % CL CLAY(CL):dark gray to greenish gray,moist F-H Mp 20 37 31 LL S-7 5 Z 1 7 F1 ! o - El. 1 c o Project Number: 115042 Plate 0 BORING LOG B-2 \ Date: 01-10-11 10f 2 O z ' KL EINFEL DER Entry By: MWS A/+�-3 Fe Bright People.Right Solutions. �7 oo Checked By: RKW Tigard Costco Fuel Facility Addition o File Name: in .1 .0 ` �rms's a► .. .w Boring Number B-2 Location:Tigard,OR Drilling Method:Mud Rotary Boring Total Depth:41.5 ft Coordinates()UY,LatlLong): ft/ ft Drilling Equipment:Diedrich D-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11/01-10-11 Top of Boring Elevation: Bit Size/Type:6-inch/Tricone Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point: ' Depth to Groundwater Initial/fime: Hammer Drop/Weight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater Final/Time: Angle From Horizontal/Bearing:90° Field Soil Description&Classification Laboratory a The report and log key are an integral part of these logs.Al!data and E interpretations in this log are subject to those stated explanations and o limitations. Z' ce 2 e M m c c or at S E m g+ rp v «_ m 'r'° E E • " ° . E T • v m c a m H Other Tests E a a A aH ac. and o ff in m d 0 Description 3 a a a 3 o as au Field Notes t ' ML SILT With Said(ML):dark gray,moist,fine sand D Np • 25- 8 ti 40 S-9 10 '.� 14 ` WILLAMETTE SILT J ti ML SILT(ML):grayish brown,moist F Lp 8 S-10 7 8 a a n. ML SILT(ML):brown,moist D Np LI of 9 33 m S-11 14 o 20 e cc a m ML SILT With Sand(ML):gray,moist,fine sand Md Np z ', C 0 8 w S-12 13 15 w Y Depth to groundwater obscured by mud rotary drilling techniques;therefore,no groundwater level reported. cal Boring completed at a depth of 41.5 ft below existing 0. site grade. 1- ui r w O a ix S Project Number: 115042 ' Plate $ /-- BORING LOG B-2 Date: 01-10-11 2 of 2 o o - KL KLEINFELDER Entry By: MWS A-3 o Bright People.Right Solutions. Checked By: RKW Tigard Costco Fuel Facility Addition ro o File Name: • 1 �u . •{d xf 1 Boring Number:B-3 Location:Tigard,OR Drilling Method:Hollow-stem auger Boring Total Depth:11.5 ft Coordinates()(/Y,Lat/Long): ft/ ft Drilling Equipment:Diedrich 0-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11/01-10-11 Top of Boring Elevation: Bit Size/Type:8-inch/Cutting Head Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point: Depth to Groundwater Initial/Time: Hammer Drop/Weight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater Final/Time: Angle From Horizontal/Bearing:90° Field Soil Description&Classification Laboratory The report and log key are an integral part of these logs.All data and interpretations in this log are subject to those stated explanations and oG limitations. ' N C �.m ... m DI = z' ro E �� E c 3 X a c L m . n n t •p W u u ' - c 5 m ac Other Tests ra m m .Ea o vii o ° m w w ` my 6o and o ff rn m d CD a Description L� I a 3 c aa� a Fieid Notes — 3 inches of ASPHALT CONCRETE i < AGGREGATE BASE:(8 inches) ML SILT With Sand(ML):dark brown,moist F Lp 3 I FILL 28 S-1 2 2 ML SST With Sand(ML):brown,moist,fine sand Md Np 3 71 S-2 6 7 • WILLAMETTE SILT 3 ML SILT(ML):brown,moist F Np-Lp 32 S-3 2 4 10 1 ° S-4 2 2 Groundwater not encountered at time of drilling. Boring completed at a depth of 11.5 ft below existing site grade. e rr r 1S ❑ H N z z 3 cc w W z Z W . H co• 20. ❑ fn W QH o O cc Project Number 115042 Plate Date: 01-10-11 BORING LOG B-3 1 of 1 o z KL EINFEL DER Entry By: MWS A-4 Bright People.Right Solutions. Checked By: RKW Tigard Costco Fuel Facility Addition o File Name: .r:i y, a' "4".4.,.:...". C4 ` ':,.'• .. . ' r . Y ''"5'..74.' •,:',r Y's s I Sis. .q.b Boring Number B-4 Location:Tigard,OR Drilling Method:Hollow-stem auger Boring Total Depth:11.5 ft Coordinates(X/Y,LatLong): ft/ ft Drilling Equipment Diedrich D-50 Depth to Rock:No Rock was Encountered Datum/Coordinate System: Drilling Company:Subsurface Technologies Date Begin/End:01-10-11/01-10-11 Top of Boring Elevation: Bit Size/Type:8-inch/Cutting Head Surface Conditions:Asphalt Concrete Coordinate Data Source: Hammer Type/Method:Auto-Trip WL Measurement Point: Depth to Groundwater Initial/Time: Hammer DroplWeight:30 in./140 lbs. Logged By:M.Swank Depth to Groundwater Final/Time: Angle From HorizontalBearing:90° Field Soil Description&Classification Laboratory The report and log key are an integral part of these logs.At data and C E interpretations in this log are subject to those stated explanations and .7., a E. C limitations. co 2 c S " F,.. c rn e m d e S uc c r :: °' r d T �j y J E C« E C 3 r. y y k ti fq ea C J, J V .L" co W pyN I t m E a u v E d CU) Other Tests 1. E E ' ' n c a W w _ m ph mo and d l A m d a Description ° °' r m `O^' Field Notes o f rn c�a s a � 3 o rs� aae 5 3 inches of ASPHALT CONCRETE _ I S-1 2 AGGREGATE BASE:(6 inches) 3 I. ;1: ML SILT With Sand(ML):brown,moist,fine sand Md Np I. • ., 4 FILL ' S-2 6 ,•' 6 ML SILT(ML):brown,moist F Np-lp S - 3 29 S-3 2 _ 2 WILLAMETTE SILT S 4 3 j CL CLAY(CL):dark gray,moist F Mp - 4 %/ 1 1 28 e a S5 5 _ aGroundwater not encountered at time of drilling. N Boring completed at a depth of 11.5 ft below existing g site grade. m J LI O - cc } a 15 m - _ V) Z o cc W 9 - - W z Z W - J Y I- CI 20 LI 1-) QF Ko h coy Project Number: 115042 j Plate $ /�� BORING LOG B-4 Date: 01-10-11 1 of 1 o ! KL E/NFEL OER Entry By: MWS Z A-5 R Bright People.Right Solutions. co Checked By: RKW Tigard Costco Fuel Facility Addition o File Name: u), . a.. yr .•;=•444}',.4.,, ' - r 1 'J .V ,T+ A -e4 i.-F a �. f i w . • Appendix B Laboratory g • n • KL E/NFEL DER Biyhl People Right SOlulgnt APPENDIX B GEOTECHNICAL LABORATORY TESTING General Laboratory tests were conducted on selected representative soil samples to better identify the soil classification of the units encountered and to evaluate the material's general physical properties and engineering characteristics. A brief description of the tests performed for this study is provided below. The results of laboratory tests performed on specific samples are provided at the appropriate sample depths on the individual boring logs. However, it is important to note that these test results may not accurately represent in situ soil conditions. Our recommendations are based on our interpretation of these test results and their use in guiding our engineering judgment. In accordance with your requirements, the soil samples for this project will be retained a period of 3 months following completion of this report, or until the foundation installation is complete, unless we are otherwise directed in writing. Visual Manual Soil Classification Soil samples were visually examined in the field by our representative at the time they were obtained. They were subsequently packaged and returned to our laboratory where they were reexamined and the original description checked and verified or modified. With the help of information obtained from the other classification tests, described below, the samples were described in general accordance with the Unified Classification System, ASTM Standard D2487. The resulting descriptions are provided at the appropriate locations on the individual boring logs, located in Appendix A, and are qualitative only. Moisture Content Moisture content tests were performed on 16 samples obtained from the borings. The purpose of these tests is to approximately ascertain the in-place moisture content of the soil sample at the time it was collected. The moisture content is determined in general accordance with ASTM Standard D2216. The results of these tests are presented at the appropriate sample depths on the boring logs. 115042/POR11 R021 Page B-1 February 28, 2011 Copyright 2011 Kleinfelder LK EINFELOER &iyht People Riyht Sotot;,,. Atterberg Limits Two Atterberg limits were determined on selected samples for the purpose of classifying fine-grained soils into various groups for correlation. The results of the Atterberg limits tests, which included liquid and plastic limits, are plotted on the Plasticity Chart on Figure B-2, and on the log of the borings in Appendix A. Grain-size Distribution The grain-size distribution was performed on two samples in general accordance with ASTM Standard D422 to determine the amount of material passing the U.S. Standard No. 200 size sieve (material less than 0.075 mm). The information from this analysis allows us to provide a detailed description and classification of the subsurface materials and helps us understand soil reactions to conditions such as loading and potential liquefaction. 115042/POR11 R021 Page B-2 February 28, 2011 Copyright 2011 Kleinfelder SIEVE SIZE 6" 3" 1-1/2" 3/4" 3/8" #4 #8#10 #16 #30 #40 #50 #100 #200 100 : i : i - I_ i 90 . 80 : 70 a • I _ I: f. 20— 10 . 0 •• 100 10 1 0.1 PARTICLE SIZE IN MILLIMETERS • COBBLE GRAVEL SAND coarse fine coarse medium fine a aN lli d LEGEND: SOURCE DEPTH COBBLE GRAVEL SAND FINES D60 D10 Cu Cc DESCRIPTION o (ft) (%) (%) (%) (%) (mm) (mm) 5 • B-1 2.5 0 0 0 72 LEAN CLAY with SAND $ (CL) f y m B-3 5.0 0 0 0 71 SILT(ML)with SAND cc a cc m J O L-- N H Z co LE w O J w L.L. z W J Y I- 0 O 0 i- v) w Project Number: 115042 Figure GRAIN SIZE ANALYSES LL c.--/'---.-- Date: 02-07-11 z KLEINFELDER Entry By: MWS Y B-1 w Bright People.Right Solutions. W Checked By: RKW Tigard Costco Fuel Facility Addition 1 File Name: f74.A.. 60 70 80 90 10 GROUP UNIFIED SOIL CLASSIFICATION SYMBOL FINE GRAINED SOIL GROUPS / Organic silts and organic silty // Z OI' clays of low plasticity / Inorganic clayey silts to very r // U.LINE A-UNE O 1414 fine sands of slight plasticity // Z LL Inorganic clays of low // Jto moderate plasticity / a Organic clays of moderate to high / Wplasticity,organic silts % CH imo Inorganic silts and /a� clayey silts / 40 1 Inorganic clays of - a 1‘"F9 high plasticity / / K / W O I / _ / , — — 30 1 Ill ar t ci J • // i0 a f m — - 20 N / / / / 10 I /. _- 10 / I I* ir II I I 0 N 10 20 30 40 50 60 70 80 90 100 V O in LIQUID LIMIT(LL) 0 J r7 r O LEGEND: SOURCE DEPTH(ft) LL PL PI DESCRIPTION • B-1 2.5 41 19 22 LEAN CLAY with SAND(CL) • co 2 I B-2 17.5 37 17 20 CLAY(CL) m FNF cc W 0 J W LL Z w J Y ,— 0 (7 0 1- ro cc w 0 J u. Project Number: 115042 Figure W ^ PLASTICITY CHART Y , \ Date: 02-07-11 cc KL E/NFEL DER Entry By: MWS B-2 W Bright People.Right Solutions. Checked By: RKW Tigard Costco Fuel Facility Addition a / File Name: •• KL EINFEL DER Srtghl People.Riyhl Solobon,. APPENDIX C IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT 115042/POR11 R021 Page C-1 February 28, 2011 Copyright 2011 Kleinfelder o Important Information About Your Geotechnical Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes The following information is provided to help you manage your risks. Geotechnical Services Are Performed for •elevation,configuration,location,orientation,or weight of the Specific Purposes, Persons, and Projects proposed structure, Geotechnical engineers structure their services to meet the specific needs of •composition of the design team,or their clients.A geotechnical engineering study conducted for a civil engineer • project ownership. may not fulfill the needs of a construction contractor or even another civil engineer.Because each geotechnical engineering study is unique,each geo- As a general rule, always inform your geotechnical engineer of project technical engineering report is unique,prepared solely for the client.No one changes-even minor ones -and request an assessment of their impact. except you should rely on your geotechnical engineering report without first Geotechnical engineers cannot accept responsibility or liability for problems conferring with the geotechnical engineer who prepared it.And no one-not that occur because their reports do not consider developments of which they even you-should apply the report for any purpose or project except the one were not informed. originally contemplated. Subsurface Conditions Can Change Read the Full Report A geotechnical engineering report is based on conditions that existed at the Serious problems have occurred because those relying on a geotechnical time the study was performed. Do not rely on a geotechnical engineering engineering report did not read it all.Do not rely on an executive summary. report whose adequacy may have been affected by:the passage of time;by Do not read selected elements only. man-made events,such as construction on or adjacent to the site;or by natu- ral events,such as floods,earthquakes,or groundwater fluctuations.Always A Geotechnical Engineering Report Is Based on contact the geotechnical engineer before applying the report to determine if it A Unique Set of Project-Specific Factors is still reliable.A minor amount of additional testing or analysis could prevent Geotechnical engineers consider a number of unique,project-specific factors major problems. when establishing the scope of a study.Typical factors include:the client's goals,objectives,and risk management preferences;the general nature of the Most Geotechnical Findings Are Professional structure involved, its size,and configuration;the location of the structure Opinions on the site;and other planned or existing site improvements,such as access Site exploration identifies subsurface conditions only at those points where roads,parking lots,and underground utilities.Unless the geotechnical engi- subsurface tests are conducted or samples are taken.Geotechnical engineers neer who conducted the study specifically indicates otherwise,do not rely on review field and laboratory data and then apply their professional judgment a geotechnical engineering report that was: to render an opinion about subsurface conditions throughout the site.Actual •not prepared for you, subsurface conditions may differ-sometimes significantly from those indi- •not prepared for your project, cated in your report.Retaining the geotechnical engineer who developed your •not prepared for the specific site explored,or report to provide construction observation is the most effective method of •completed before important project changes were made. managing the risks associated with unanticipated conditions. Typical changes that can erode the reliability of an existing geotechnical A Report's Recommendations Are Not Final engineering report include those that affect: Do not overrely on the construction recommendations included in your re- •the function of the proposed structure,as when it's changed from a port. Those recommendations are not final,because geotechnical engineers parking garage to an office building,or from alight industrial plant develop them principally from judgment and opinion.Geotechnical engineers to a refrigerated warehouse, can finalize their recommendations only by observing actual e . subsurface conditions revealed during construction.The geotechnical engi- to disappointments, claims,and disputes.To help reduce the risk of such neer who developed your report cannot assume responsibility or liability for outcomes,geotechnical engineers commonly include a variety of explanatory the report's recommendations if that engineer does not perform construction provisions in their reports. Sometimes labeled limitations" many of these observation. provisions indicate where geotechnical engineers' responsibilities begin and end,to help others recognize their own responsibilities and risks.Read A Geotechnical Engineering Report Is Subject to these provisions closely.Ask questions.Your geotechnical engineer should Misinterpretation respond fully and frankly. Other design team members' misinterpretation of geotechnical engineer- ing reports has resulted in costly problems. Lower that risk by having your Geoenvironmental Concerns Are Not Covered geotechnical engineer confer with appropriate members of the design team The equipment,techniques, and personnel used to perform a geoenviron- after submitting the report.Also retain your geotechnical engineer to review mental study differ significantly from those used to perform a geotechnical pertinent elements of the design team's plans and specifications.Contractors study.For that reason,a geotechnical engineering report does not usually re- can also misinterpret a geotechnical engineering report.Reduce that risk by late any geoenvironmental findings,conclusions,or recommendations;e.g., having your geotechnical engineer participate in prebid and preconstruction about the likelihood of encountering underground storage tanks or regulated conferences,and by providing construction observation. contaminants. Unanticipated environmental problems have led to numerous project failures.If you have not yet obtained your own geoenvironmental in- , Do Not Redraw the Engineer's Logs formation,ask your geotechnical consultant for risk management guidance. Geotechnical engineers prepare final boring and testing logs based upon Do not rely on an environmental report prepared for someone else. their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering report should Obtain Professional Assistance To Deal with Mold never be redrawn for inclusion in architectural or other design drawings. Diverse strategies can be applied during building design,construction,op- Only photographic or electronic reproduction is acceptable, but recognize eration,and maintenance to prevent significant amounts of mold from grow- that separating logs from the report can elevate risk. ing on indoor surfaces.To be effective,all such strategies should be devised for the express purpose of mold prevention,integrated into a comprehensive Give Contractors a Complete Report and plan,and executed with diligent oversight by a professional mold prevention Guidance consultant. Because just a small amount of water or moisture can lead to Some owners and design professionals mistakenly believe they can make the development of severe mold infestations,a number of mold prevention contractors liable for unanticipated subsurface conditions by limiting what strategies focus on keeping building surfaces dry.While groundwater,wa- they provide for bid preparation.To help prevent costly problems,give con- ter infiltration,and similar issues may have been addressed as part of the tractors the complete geotechnical engineering report,butpreface it with a geotechnical engineering study whose findings are conveyed in-this report, clearly written letter of transmittal.In that letter,advise contractors that the the geotechnical engineer in charge of this project is not a mold prevention report was not prepared for purposes of bid development and that the report's consultant: none of the services performed in connection with accuracy is limited;encourage them to confer with the geotechnical engineer the geotechnical engineer's study were designed or conducted who prepared the report(a modest fee may be required)and/or to conduct ad- for the purpose of mold prevention.Proper implementation of ditional study to obtain the specific types of information they need or prefer. the recommendations conveyed in this report will not of itself A prebid conference can also be valuable.Be sure contractors have sufficient be sufficient to prevent mold from growing in or on the struc- time to perform additional study.Only then might you be in a position to give lure involved. contractors the best information available to you,while requiring them to at least share some of the financial responsibilities stemming from unantici- Rely on Your ASFE-Member Geotechnical pated conditions. Engineer For Additional Assistance Membership in ASFE/The Best People on Earth exposes geotechnical engi- Read Responsibility Provisions Closely neers to a wide array of risk management techniques that can be of genuine Some clients,design professionals,and contractors do not recognize that benefit for everyone involved with a construction project. Confer with your geotechnical engineering is far less exact than other engineering disciplines. ASFE-member geotechnical engineer for more information. This lack of understanding has created unrealistic expectations that have led ASFE ire Best People II Earth 8811 Colesville Road/Suite G106,Silver Spring,MD 20910 Telephone:'301/565-2733 Facsimile:301/589-2017 e-mail:info @asfe.org www.asfe.org Copyright 2004 by ASFE,Inc.Duplication,reproduction,or copying of this document,in whole or in part,by any means whatsoever,is strictly prohibited,except with ASFE specific written permission.Excerpting,quoting,or otherwise extracting wording from this document is permitted only with the express written permission of ASFE,and only for purposes of scholarly research or book review.Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report.Any other firm, individual,or other entity that so uses this document without being anASFE member could be committing negligent or intentional(fraudulent)misrepresentation. IIGER06045.0M