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DESIGN`i December 5, 2014 Polygon Northwest Company 109 East 13`h Street Vancouver, WA 98660 Attention: Mr. Fred Gast Report of Geotechnical Engineering Services Bull Mountain Ill 16650 - 16920 SW Bull Mountain Road Tigard, Oregon GeoDesign Project: Polygon-124-01 We are pleased to present our report of geotechnical engineering services for the proposed Bull Mountain Ill residential development located within the urban growth boundary in Tigard, Oregon. The approximately 25-acre site is located southeast of the intersection of SW Bull Mountain Road and SW Roy Rogers Road and is currently occupied by four residences, associated outbuildings, agricultural areas, and vacant land. We appreciate the opportunity to be of service to you. Please contact us if you have questions regarding this report. Sincerely, GeoDesign, Inc. Signed for Scott V. Mills, P.E., G.E. Principal Engineer cc: Mr.Jim Lange, Pacific Community Design (via email only) Mr. Chris Walther, Polygon Northwest Company(via email only) SMD:BAS:kt Attachments One copy submitted(via email only) Document ID:Polygon-124-01-120514-geor.docx ©2014 GeoDesign,Inc. All rights reserved. 15575 SW Sequoia Pkwy,Suite 100 I Portland,OR 97224 1503.968.8787 www.geodesigninc.com TABLE OF CONTENTS PAGE NO. 1.0 INTRODUCTION 1 2.0 PURPOSE AND SCOPE 1 3.0 BACKGROUND 2 4.0 SITE CONDITIONS 2 4.1 Regional Geology 2 4.2 Surface Conditions 3 4.3 Subsurface Conditions 3 5.0 CONCLUSIONS AND RECOMMENDATIONS 4 5.1 General 4 5.2 Site Preparation 5 5.3 Construction Considerations 6 5.4 Trench Excavations 7 5.5 Structural Fill 8 5.6 Drainage Considerations 11 5.7 Permanent Slopes 12 5.8 Shallow Foundations 12 5.9 Floor Slabs 12 5.10 Resistance to Sliding 13 5.11 Retaining Structures 13 5.12 Seismic Considerations 15 5.13 Pavement Design Recommendations 15 6.0 OBSERVATION OF CONSTRUCTION 16 7.0 LIMITATIONS 17 FIGURES Vicinity Map Figure 1 Site Plan Figure 2 APPENDIX Field Explorations A-1 Laboratory Testing A-1 Exploration Key Table A-1 Soil Classification System Table A-2 Test Pit Logs Figures A-1 -A-12 Atterberg Limits Test Results Figure A-13 Summary of Laboratory Data Figure A-14 ACRONYMS G EODESIGN= Polygon-124-01:120514 1.0 INTRODUCTION GeoDesign, Inc. is pleased to present our geotechnical engineering report for the proposed Bull Mountain Ill residential development in Tigard, Oregon. The approximately 25-acre site is located southeast of the intersection of SW Roy Rogers Road and SW Bull Mountain Road with addresses of 16650 through 16920 SW Bull Mountain Road. The site is currently occupied by four residences, associated outbuildings, agricultural areas, and vacant land. Figure 1 shows the site relative to existing topographic and physical features We understand the site will be developed with a mix of detached single-family homes and townhome buildings with associated roads, parks, and open areas. Based on the generally southwest sloping terrain with slope grades of approximately 5 to 10 percent,we assume maximum cuts and fills will range up to approximately 10 feet. We expect the residential structures will be of wood-framed construction. We have assumed foundation loads will be typical of single-family,wood-framed residential construction. Floor slab loading is also expected to be less than approximately 100 psf. For your reference, acronyms used herein are defined at the end of this document. 2.0 PURPOSE AND SCOPE The purpose of our work was to explore site subsurface conditions and provide geotechnical engineering recommendations for use in design and construction of the proposed development. The specific scope of our services is summarized as follows: • Reviewed readily available published geologic data and our in-house files for existing information on subsurface conditions in the site vicinity. • Coordinated and managed the field investigation, including utility checks and scheduling of subcontractors and GeoDesign field staff. • Explored subsurface conditions by excavating 12 test pits to depths ranging between 9.0 and 15.0 feet BGS. • Obtained soil samples for laboratory testing, and maintained a log of encountered soil and groundwater conditions in each exploration. • Completed a laboratory testing program on selected soil samples collected from our explorations. Specifically, we completed the following: • Twenty-six moisture content determinations in general accordance with ASTM D 2216 • Two Atterberg limits determinations in general accordance with ASTM D 4318 • One percent fines determination in general accordance with ASTM D 1 140 • Provided recommendations for site preparation and grading, including demolition, temporary and permanent slopes, fill placement criteria, suitability of on-site soil for fill, subgrade preparation, and recommendations for wet weather construction. • Provided recommendations for excavation and excavation support. • Provided shallow foundation recommendations for the support of the proposed structures, including allowable bearing capacity, estimated settlement, and lateral resistance. • Provided recommendations for use in the design of conventional retaining walls, including backfill and drainage requirements and lateral earth pressures. G EODE$IGN= 1 Polygon-124-01:120514 • Provided recommendations for construction of asphalt pavements for on-site access roads and parking areas, including subbase, base course, and asphalt paving thickness. • Evaluated groundwater conditions at the site. Provided general recommendations for dewatering during construction and subsurface drainage, if required. • Provided recommendations for IBC seismic coefficients. • Prepared this geotechnical engineering report presenting our findings, conclusions, and recommendations. 3.0 BACKGROUND GeoDesign prepared a December 5, 2014 environmental report' for the site. A water supply well was identified for the residence at 16830 SW Bull Mountain Road (on Tax Lot 1300) and another well was reported for the residence at 16880 SW Bull Mountain Road (on Tax Lot 1900). We understand sewage generated by all four of the residences at the site is discharged to on-site septic systems. 4.0 SITE CONDITIONS 4.1 REGIONAL GEOLOGY The site is located on the western flank of Bull Mountain,which is in the southeastern portion of the Tualatin Basin physiographic province. The Tualatin Basin is a northwest-to southeast- trending structural basin bound by the Portland Hills and Tualatin Mountains to the north and east(respectively)and the Chehalem Mountains and Coast Range to the south and west (respectively). The near-surface geologic unit is mapped by Madin (1990)2 and Schlicker and Deacon (1967)3 as Pleistocene Age (30,000 to 10,000 years before present) loess deposits that correlate to the Portland Hills Silt. The deposits consist of unconsolidated, micaceous, sandy silt and silty clay that was wind-deposited on the Tualatin Basin uplands. The thickness of the loess deposits is not known in the site vicinity; however, it is our opinion that it does not exceed 20 feet in thickness. The western-most portion of the site is mapped near the boundary of fine-grained catastrophic flood deposits from outbursts of Glacial Lake Missoula. The flood deposits generally consist of unconsolidated, fine sand, silt, and clay. The loess and flood deposits unconformably overlie the Miocene Age (16.5 million to 15.5 million years before present) Grande Ronde Basalt member of the Columbia River Basalt Group. Flows of the Columbia River Basalt generally range in thickness from 30 to 60 feet and the upper surface of the basalt typically weathers to a red-brown, sandy clay soil. The Grande 'GeoDesign,Inc.,Phase I Environmental Site Assessment and Limited Surface Soil Evaluation;Bull Mountain III; 16650- 16920 5141 Bull Mountain Road;Tigard,Oregon,dated December 5,2014. GeoDesign Project: Polygon-124-02 2 Madin,Ian P., 1990,Earthquake-Hazard Geology Maps of the Portland Metropolitan Area,Oregon:Text and Map Explanation,Oregon Department of Geology and Mineral Industries,Open-File Report 0-90-2,21 p.,8 plates. Schlicker,Herbert G.,and Deacon,Robert J., 1967,Engineering Geology of the Tualatin Valley Region,Oregon:Oregon Department of Geology and Mineral Industries Bulletin 60, 103 p. C EQDESIGN? 2 Polygon-124-01:120514 Ronde Basalt is one of a series of basalt flows that originated from southeastern Washington and northeastern Oregon and is considered to be the geologic basement unit for the purpose of this report. 4.2 SURFACE CONDITIONS The site is accessible from residential driveways located on SW Bull Mountain Road. The property consists of six tax lots (1300, 1302, 1303,1305, 1900, 2000) bound by residential properties to the east, SW Bull Mountain Road and agricultural land to the north, a vegetated drainage to the south, and SW Roy Rogers Road to the west. The site consists of four single-family residence homes with associated outbuildings located at 16880, 16830, 16780, and 16650 SW Bull Mountain Road and recently tilled, predominantly grass-and weed-vegetated agricultural land. The homes are situated in the northern portion of the site near SW Bull Mountain Road as shown on Figure 2. Fill has been placed to create a flat area below the barn in the southern portion of Tax Lot 1900. The northeast corner of the site (north half of Tax Lot 1303) contains conifer trees left over from a Christmas tree farming operation. A small drainage crosses the southeast corner of the site. In general, topography of the site slopes downward to the southwest. Two smaller areas slope to the northwest, one at the northwest corner of the site near the intersection of SW Roy Rogers Road with SW Bull Mountain Road and a second at the southeast corner of the site near a drainage crossing that corner of the site. Elevations at the site range from 335 feet at the northeast corner of the site down to 255 feet at the southwest corner of the site. 4.3 SUBSURFACE CONDITIONS Our subsurface exploration program consisted of excavating 12 test pits (TP-1 through TP-12) to depths ranging between 9.0 and 15.0 feet BGS. Descriptions of the geotechnical field explorations and laboratory testing and logs of the explorations are provided in the Appendix. Approximate exploration locations are shown on Figure 2. We encountered an approximate 10- to 15-inch-thick tilled zone at the ground surface due to past agricultural activities in most of our explorations. In the vegetated areas, there was an approximately 3-to 6-inch-thick root zone associated with the surface vegetation at the time of our explorations. The subsurface conditions generally consist of silt and clay soil overlying decomposed to weathered basalt. The subsurface soil is described in the following sections. 4.3.1 Undocumented Fill Undocumented fill composed of silt or clay was encountered to depths of 5.5 to 2.0 feet BGS in test pits TP-2 and TP-8, respectively. The silt or clay fill material varies from soft to stiff and brown with varying amounts of sand. Concrete and brick debris was also observed in the fill in TP-8. Laboratory testing indicates that the moisture contents of the silt or clay fill ranged between 23 and 32 percent at the time of our explorations. 4.3.2 Silt and Clay Native silt or clay was encountered in all of the explorations underlying the tilled zone that extends to depths ranging from 8.5 to 15.0 feet BGS. The silt and clay generally is medium stiff to very stiff, becoming stiffer with increasing depth, and brown with varying amounts of sand. Laboratory testing indicates that the moisture contents of the silt and clay ranged between 26 and 33 percent at the time of our explorations. G E0DE5lGN`i 3 Polygon-124-01:120514 4.3.3 Silt,Silty Sand,and Gravel (Decomposed to Weathered Basalt) The silt and clay transitions to decomposed basalt soil consisting of hard silt, dense sand, and dense gravel, which was encountered at depths ranging from 6.0 to 13.5 feet BGS in test pits TP-1, TP-3,TP-6, TP-8, TP-9,TP-10, and TP-12. The hard and dense soil is a matrix containing variable amounts of gravel, sand, silt, clay, cobbles, and boulders. Refusal was encountered in test pits TP-3, TP-6, TP-8, TP-9, TP-10, and TP-12 at depths ranging from 9.0 and 12.5 feet BGS using aJohn Deere 310E backhoe with a toothed bucket. The depth to refusal likely indicates an increase in competent basalt and a decrease in weathering. The depths to decomposed basalt and refusal for the test pits are shown on Figure 2. Laboratory testing indicates that the moisture contents of the variable decomposed basalt soil ranged between 21 and 40 percent at the time of our explorations. 4.3.4 Groundwater Groundwater seepage was observed in five excavations (TP-3, TP-5, TP-6, TP-10, and TP-1 1)at the time of our explorations and was observed between 8.0 and 11.0 feet BGS. Water was also observed at the base of the drainage crossing the southeast corner of the site. Perched groundwater may be present at shallow depths during the wet season or following periods of heavy rainfall. The depth to groundwater may fluctuate in response to seasonal changes, changes in surface topography, and other factors not observed during our explorations. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 GENERAL Based on the results of our explorations, laboratory testing, and analyses, it is our opinion that the site is suitable for the proposed development. The following sections discuss geotechnical design considerations for the proposed development. Decomposed rock was encountered in test pits TP-1,TP-3, TP-6, TP-8, TP-9, TP-10, and TP-12 at depths ranging from 6.0 to 13.5 feet BGS. Refusal was also encountered in test pits TP-3,TP-6, TP-8, TP-9, TP-10, and TP-12 at depths ranging from 9.0 and 12.5 feet BGS using a John Deere 310E backhoe with a toothed bucket. If cuts extend deeper than the depth of refusal in our test pit explorations, less weathered, stronger rock should be anticipated. If encountered, the rock may require blasting and/or the use of a hydraulic rock breaker for excavation. Rock excavation methods may also be required for trenches or smaller excavation areas below the depth of refusal in our test pit explorations or where boulders are encountered in the overlying decomposed basalt. A 10-to 15-inch-thick tilled zone was observed in the explorations at the site. Proper stripping operations will likely remove some of the tilled zone. The tilled zone not already removed from cuts and site stripping will need to be removed or stabilized. Scarification and compaction of the tilled zone will likely not be possible unless completed during the summer dry period. Removal and replacement of the tilled zone with granular material or cement amendment will be necessary if stabilization is not possible. The silt at the site is sensitive to small changes in moisture content and difficult, if not impossible, to adequately compact during wet weather or when the moisture content of the soil G EO DESIGN= 4 Polygon-124-01:120514 is more than a couple of percent above the optimum required for compaction. As discussed in the following sections, the moisture content of the soil is above that required for compaction, and drying will be required for use as structural fill. Our specific recommendations for site development are presented in the following sections of this report. There are existing water wells and septic systems associated with the residences at the site. Water supply wells and septic systems on the site should be abandoned in accordance with state and local regulations prior to site development. Variable undocumented fill was encountered in test pits TP-2 and TP-8 to depths of 5.5 and 2.0 feet BGS, respectively. The fill encountered in test pit TP-2 was placed to create a terraced flat area south of the barn in Tax Lot 1900. There may also be other small areas of undocumented fill associated with the current residential dwellings at the site. Undocumented fill will provide inadequate support for structures and should be removed and replaced or improved in structural areas as recommended in the "Site Preparation" section of this report. 5.2 SITE PREPARATION 5.2.1 Demolition We anticipate the existing residences and other structures will be demolished as part of the site preparation activities. Demolition includes complete removal of existing site improvements within 5 feet of areas to receive new pavements, buildings, retaining walls, or engineered fills. Underground vaults, tanks, manholes, and other subsurface structures should be removed in areas of new improvements. Utility lines should be completely removed. Existing basements, crawl spaces, or other voids resulting from removal of existing improvements should be backfilled with compacted structural fill, as discussed in the "Structural Fill" section of this report. The bottom of such excavations should be excavated to expose a firm subgrade before filling and their sides sloped at a minimum of 1 H:1 V to allow for more uniform compaction at the edges of the excavations. We recommend the water wells on the property be decommissioned in accordance with OWRD regulations. In addition, the septic tanks should be pumped out, removed, and disposed properly. Septic leach fields (if present) should also be excavated and disposed properly. Resulting excavations should be backfilled with structural fill. 52.2 Grubbing and Stripping Trees should be removed from all proposed building, pavement, and sidewalk areas. In addition, root balls should be grubbed out to the depth of the roots, which could exceed 3 feet BGS. Depending on the methods used to remove the root balls, considerable disturbance and loosening of the subgrade could occur during site grubbing. We recommend that soil disturbed during grubbing operations be removed to expose firm, undisturbed subgrade. The resulting excavations should be backfilled with structural fill. The existing root zone should be stripped and removed from the site in all proposed building and pavement areas and for a 5-foot margin around such areas. The depth of stripping will depend on the vegetation; however,we expect the average depth of stripping will be approximately 3 to 4 inches. Greater stripping depths may be required to remove localized G EO DESIGN? 5 Polygon-124-01:120514 zones of loose or organic soil, and the actual stripping depth should be based on field observations at the time of construction. Stripped material should be transported off site for disposal or used in landscaped areas. 52.3 Tilled and Topsoil Zone Material Preparation A 10-to 15-inch-thick tilled zone was observed at the site. Tilled zones typically consist of disturbed, loose soil and contain slightly higher organic contents. The tilled soil generally exhibits low strength and does not provide adequate subgrade support for foundation elements or pavements. Proper stripping operations will likely remove some of the tilled zone. The remaining tilled zone will need to be removed or stabilized in proposed fill areas and in cut areas where cuts are less than the thickness of the tilled zone. Stabilization options include scarifying and compacting or cement amendment. All fill or cement-amended soil should be completed as recommended in the "Structural Fill" section of this report. Because of the moisture-sensitive nature of the on-site soil, scarification and compaction of the tilled zone material should be completed during the summer dry period. Removal and replacement of the tilled zone material with granular material or cement amendment will be necessary if the work is scheduled during wet conditions. 52.4 Subgrade Evaluation Proof rolling should be conducted after site preparation and mass grading activities have been completed. The subgrade should be proof rolled with a fully loaded dump truck or similar heavy, rubber-tired construction equipment to identify soft, loose, or unsuitable areas. A member of our geotechnical staff should observe proof rolling to evaluate yielding of the ground surface. Soft or loose zones identified during proof rolling should be excavated and replaced with compacted structural fill. Areas that appear too wet or soft to support proof rolling equipment should be prepared in accordance with recommendations for wet weather construction provided in the "Construction Considerations" section of this report. 5.2.5 Test Pit Locations The test pit excavations were backfilled using the relatively minimal compactive effort of the hoe bucket; therefore, soft spots can be expected at these locations. We recommend that the relatively uncompacted soil be removed from the test pits to a depth of 3 feet below finished subgrade. If a test pit is located within 10 feet of a footing, we recommend full-depth removal of the uncompacted soil. The resulting excavation should be brought back to grade with structural fill. 5.3 CONSTRUCTION CONSIDERATIONS Fine-grained soil present on this site is easily disturbed during the wet season. If not carefully executed, site preparation, utility trench work, and roadway excavation can create extensive soft areas and significant repair costs can result. Earthwork planning should include considerations for minimizing subgrade disturbance. If construction occurs during the wet season, or if the moisture content of the surficial soil is more than a couple percentage points above the optimum, site stripping and cutting may need to be accomplished using track-mounted equipment, loading removed material into trucks supported on granular haul roads. C EO DESIGN= 6 Polygon-124-01:120514 The thickness of the granular material for haul roads and staging areas will depend on the amount and type of construction traffic. Generally, a 12-to 18-inch-thick mat of granular material is sufficient for light staging areas and the basic building pad but is generally not expected to be adequate to support heavy equipment or truck traffic. The granular mat for haul roads and areas with repeated heavy construction traffic typically needs to be increased to between 18 to 24 inches. The actual thickness of haul roads and staging areas should be based on the contractor's approach to site development and the amount and type of construction traffic. The imported granular material should meet the requirements provided in the "Structural Fill" section of this report. Stabilization material may be used as a substitute provided at least the top 4 inches of material consists of imported granular material. The requirements for stabilization material are provided in the "Structural Fill" section of this report. In addition, we recommend a separation geotextile meeting the requirements in the "Structural Fill" section of this report be placed as a barrier between silty subgrade material and imported granular material in areas of repeated construction traffic. As an alternative to placing 12 to 24 inches of granular material, the subgrade can be stabilized using cement amendment. If this approach is used, the thickness of granular material in staging areas and along haul roads can be reduced to 4 inches. This recommendation is based on an assumed minimum unconfined compressive strength of 100 psi and a treatment depth of 12 inches for staging areas and 16 inches for haul roads. Cement amendment is further addressed in the "Structural Fill" section of this report 5.4 TRENCH EXCAVATIONS 5.4.1 Trench Cuts and Shoring Native soil encountered in our test pit explorations generally consists of silt. However, basalt cobbles and boulders may be encountered in the silt, and basalt bedrock may be encountered in excavations at the site. If encountered, basalt bedrock or basalt boulders will result in difficult trench excavations and may require special equipment and procedures for removal. If difficult excavations are encountered, trenches may also be wider than anticipated, increasing the amount of backfill material required. Trench cuts should stand vertical to a depth of approximately 4 feet provided groundwater seepage does not occur. Open excavation techniques may be used to excavate trenches with depths between 4 and 10 feet BGS provided the walls of the excavation are cut at a slope of 1.5H:1 V and groundwater seepage is not present. Sloughing and caving will likely occur if the excavation extends below the groundwater table or if seepage is present. The walls of the trench should be flattened or braced for stability and the area dewatered if seepage is encountered. Use of a trench box or other approved temporary shoring is recommended for cuts below the water table. If shoring is used, we recommend that the type and design of the shoring system be the responsibility of the contractor, who is in the best position to choose a system that fits the overall plan of operation. 5.4.2 Dewatering We anticipate that a sump located within the trench excavation likely will be sufficient to remove the accumulated water, depending on the amount and persistence of water seepage and the length of time the trench is left open. Flow rates for dewatering are likely to vary depending on G EO DESIGN= 7 Polygon-124-01:120514 location, soil type, and the season during which the excavation occurs. The dewatering systems should be capable of adapting to variable flows. If groundwater and fine-grained soil are present in the base of the utility trench excavation, we recommend over-excavating the trench by 12 to 18 inches and placing trench stabilization material in the base. 5.4.3 Safety All excavations should be made in accordance with applicable OSHA and state regulations. While we have described certain approaches to utility trench excavations in the foregoing discussion, the contractor should be responsible for selecting the excavation and dewatering methods, monitoring the trench excavations for safety, and providing shoring as required to protect personnel and adjacent areas. 5.5 STRUCTURAL FILL 5.5.1 General Structural fill includes fill beneath foundations, slabs, pavements, other areas intended to support structures, or within the influence zones of structures. Fill should only be placed over a subgrade that has been prepared in conformance with the "Site Preparation" section of this report. All material used as structural fill should be free of organic matter or other unsuitable material. The material should meet the specifications provided in OSSC 00330 (Earthwork). All structural fill should have a maximum particle size of 4 inches and contain no frozen, organic, or other deleterious material. A brief characterization of some of the acceptable material and our recommendations for its use as structural fill is provided below. 5.5.2 On-Site Material Near-surface soil at the site consists primarily of silt and clay. This soil can be used for structural fill provided it can be adequately moisture conditioned and meets the requirements provided in OSSC 00330.12 (Borrow Material). The site soil is sensitive to small changes in moisture content and is highly susceptible to disturbance when wet. Use of the on-site material as structural fill will not be possible during the wet season, which typically extends from mid-October to late May. If construction is planned for the wet season, then careful consideration of the construction methods and schedule should be made to reduce over-excavation of disturbed site soil. Laboratory testing indicates that the moisture content of the on-site material (at the time of our explorations) is greater than the anticipated optimum moisture content required for adequate compaction. It is likely that even during the dry season, drying will be required to achieve adequate compaction. We recommend using imported granular material for structural fill or cement amending soil if the on-site material cannot be properly moisture conditioned. When used as structural fill, the on-site soil should be placed in lifts with a maximum uncompacted thickness of 8 inches. The silt should be compacted to not less than 92 percent of the maximum dry density, as determined by ASTM D 1557. 5.5.3 Imported Granular Material Imported granular material used for structural fill should be pit-or quarry-run rock, crushed rock, or crushed gravel and sand and should meet the requirements set forth in OSSC 00330.14 (Selected Granular Backfill)and OSSC 00330.15 (Selected Stone Backfill). Imported granular G EODESIGNY 8 Polygon-124-01:120514 material should be fairly well graded between coarse and fine material, have less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve, and have at least two mechanically fractured faces. When used as structural fill, imported granular material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.5.4 Floor Slab Base Rock Imported granular material placed beneath building floor slabs should be clean, crushed rock or crushed gravel and sand that is fairly well graded between coarse and fine. The granular material should have a maximum particle size of 1%2 inches, have less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve, have at least two mechanically fractured faces, and meet the requirements of OSSC 00641 (Aggregate Subbase, Base, and Shoulders). The imported granular material should be placed in one lift and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.5.5 Pavement Base Rock Imported granular material used as base rock for pavements should consist of%- or 1%2-inch- minus material meeting the requirements in OSSC 00641 (Aggregate Subbase, Base, and Shoulders),with the exception that the aggregate should have less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve and at least two mechanically fractured faces. The imported granular material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.5.6 Trench Backfill Material Trench backfill for the utility pipe base and pipe zone should consist of crushed, well-graded, granular material with a maximum particle size of 1 inch and less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve and should meet OSSC 00405.14 (Trench Backfill, Class B). The material should be free of roots, organic matter, and other unsuitable material. Backfill for the pipe base and pipe zone should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D 1557, or as recommended by the pipe manufacturer. Within building, pavement, and other structural areas, trench backfill placed above the pipe zone should consist of imported granular material as specified above. The backfill should be compacted to at least 92 percent of the maximum dry density, as determined by ASTM D 1557, at depths greater than 2 feet below the finished subgrade and 95 percent of the maximum dry density, as determined by ASTM D 1557, within 2 feet of finished subgrade. In all other areas, trench backfill above the pipe zone should be compacted to at least 92 percent of the maximum dry density, as determined by ASTM D 1557. 5.5.7 Stabilization Material Stabilization material should consist of pit-or quarry-run rock, crushed rock, or crushed gravel and sand and should meet the requirements set forth in OSSC 00330.14 (Selected Granular G EoDESIGN= 9 Polygon-124-01:120514 Backfill) and OSSC 00330.15 (Selected Stone Backfill), consist of 4-to 6-inch-minus material, have less than 5 percent by dry weight passing the U.S. Standard No. 4 Sieve, and have at least two mechanically fractured faces. The material should be free of organic matter and other deleterious material. Stabilization material should be placed in one lift and compacted to a firm condition. 5.5.8 Drain Rock Drain rock should consist of angular, granular material with a maximum particle size of 2 inches and should meet OSSC 00430.11 (Granular Drain Backfill Material). The material should be free of roots, organic matter, and other unsuitable material and have less than 2 percent by dry weight passing the U.S. Standard No. 200 Sieve (washed analysis). 5.5.9 Recycled Material AC, conventional concrete, and oversized rock may be used as fill if they are processed to meet the requirements for their intended use and do not pose an environmental concern. Processing includes crushing and screening, grinding in place, or other methods to meet the requirements for structural fill as described above. The processed material should be fairly well graded and not contain metal, organic, or other deleterious material. The processed material may be mixed with on-site soil or imported fill to assist in achieving the gradation requirements. Processed recycled fill should have a maximum particle size of 4 inches. Recycled granular fill material is generally not suitable for the top 4 inches of pavement base rock or floor slab base rock. We also caution that excavation through recycled material that is placed as structural fill may be difficult. In addition, these excavations may also be prone to raveling and caving. 5.5.10 Geotextile Fabric 5.5.10.1 Separate Geotextile Fabric A separation geotextile fabric can be placed as a barrier between silty subgrade and granular material in staging areas, haul road areas, or in areas of repeated construction traffic. The subgrade geotextile should meet the requirements in OSSC 02320 (Geosynthetics) for subgrade geotextiles and be installed in conformance with OSSC 00350 (Geosynthetic Installation). 5.5.10.2 Drainage Geotextile Fabric Drain rock, and other granular material used for subsurface drains, should be wrapped in a geotextile fabric that meets the specifications provided in OSSC 00350 (Geosynthetic Installation) and OSSC 02320 (Geosynthetics) for drainage geotextiles and be installed in conformance with OSSC 00350 (Geosynthetic Installation). 5.5.11 Soil Amendment As an alternative to the use of imported granular material, an experienced contractor may be able to amend the on-site soil with portland cement to obtain suitable support properties. It is generally less costly to amend on-site soil than to remove and replace soft soil with granular material. Successful use of soil amendment depends on the use of correct mixing techniques, soil moisture content, and amendment quantities. Soil amending should be conducted in accordance with OSSC 00344 (Treated Subgrade). G EO DESIGN= 10 Polygon-124-01:120514 Specific recommendations, based on exposed site conditions, for soil amending can be provided if necessary. However, for preliminary design purposes, we recommend a target strength for cement-amended soils of 80 psi. The amount of cement used to achieve this target generally varies with moisture content and soil type. It is difficult to predict field performance of soil to cement amendment due to variability in soil response, and we recommend laboratory testing to confirm expectations. Generally, 4 percent cement by weight of dry soil can be used when the soil moisture content does not exceed approximately 20 percent. If the soil moisture content is in the range of 20 to 35 percent, 5 to 7 percent by weight of dry soil is recommended. The amount of cement added to the soil may need to be adjusted based on field observations and performance. Moreover, depending on the time of year and moisture content levels during amendment,water may need to be applied during tilling to appropriately condition the soil moisture content. The amount of cement used during treatment should be based on an assumed soil dry unit weight of 100 pcf. Typically, a minimum curing of four days is required between treatment and construction traffic access. The amended surface should be protected from abrasion by placing a minimum of 4 inches crushed rock. The crushed rock may typically become contaminated with soil during construction. Contaminated base rock should be removed and replaced with clean rock in pavement areas such that the minimum thickness of free-draining base at the surface is 4 inches. Portland cement-amended soil is hard and has low permeability. Therefore, this soil does not drain well, nor is it suitable for planting. Future planted areas should not be cement amended (if practical) or accommodations should be planned for drainage and planting. 5.6 DRAINAGE CONSIDERATIONS 5.6.1 Site Drainage We recommend that all roof drains be connected to a tightline leading to storm drain facilities. Pavement surfaces and open space areas should be sloped such that surface water runoff is collected and routed to suitable discharge points. We also recommend that ground surfaces adjacent to buildings be sloped away from the buildings to facilitate drainage away from the buildings. 5.6.2 Foundation Drains We recommend using foundation drains around the perimeter of buildings if floor slabs are constructed more than 3 feet below the existing grade or if slab-on-grade flooring is sensitive to moisture. The foundation drains should be installed at least 2 feet below the finished floor grade, constructed at a minimum slope of approximately Y2 percent, and routed to a suitable discharge (e.g., connected to the storm drain system). The foundation drains should consist of 4-inch-diameter, perforated drainpipe embedded in a minimum 2-foot-wide zone of drain rock. The drain rock should be wrapped in a drainage geotextile fabric meeting the requirements in the "Structural Fill" section of this report. Foundation drains for embedded walls should be constructed as recommended in the "Retaining Structures" section of this report. G EO DESIGNY 11 Polygon-124-01:120514 5.7 PERMANENT SLOPES Permanent slopes for soil should not exceed 2H:1 V. Footings, buildings, access roads, and pavements should be located at least 5 feet horizontally from the slope face. The slopes should be planted with appropriate vegetation as soon as possible after grading to provide protection against erosion. Surface water runoff should be collected and directed away from slopes to prevent water from running down the face of the slope. 5.8 SHALLOW FOUNDATIONS Based on the results of our explorations and laboratory testing, it is our opinion that foundation loads of the relatively light,wood-framed structures can be supported on shallow foundations bearing on firm, undisturbed native soil or structural fill bearing on this material. Preliminary design recommendations for foundations are presented below; however,we should be given the opportunity to review these recommendations once the types and locations of proposed structures are determined. Footings can be proportioned for an allowable soil bearing pressure of 2,000 psf. A higher value may be possible depending on the grading plan. The allowable bearing pressure is a net bearing pressure; the weight of the footing and overlying backfill can be ignored in calculating footing size. The allowable bearing pressure applies to the total of dead plus long-term live loads and may be doubled for short-term loads such as those resulting from wind or seismic forces. Continuous wall and spread footings should be at least 18 and 24 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the lowest adjacent final grade. The bottom of interior footings should be placed at least 12 inches below the base of the floor slab. For foundations designed in accordance with the recommendations provided above, total post- construction settlement is expected to be less than 1 inch and differential settlement between adjacent foundation elements is expected to be less than Y2 inch given the anticipated building loads. In wet weather,we recommend placing a sufficient amount of crushed rock(typically 2 to 4 inches)to prevent disturbance to the foundation subgrades. The contractor is responsible for the construction sequencing and methodology for footing excavation and construction. Consequently, the actual amount of rock placed to protect foundation subgrades from disturbance in wet weather should be selected by the contractor. Rock used to protect the subgrades during wet weather should cover the foundation bearing surfaces and be compacted until "well-keyed." Any foundation subgrade soil that is disturbed should be removed prior to the placement of crushed rock and/or pouring of the foundations. 5.9 FLOOR SLABS Satisfactory subgrade support for building floor slabs supporting floor loads of up to 100 psf can be obtained on the existing undisturbed native soil or on structural fill. A minimum 6-inch-thick layer of imported granular material should be placed and compacted over the prepared subgrade to assist as a capillary break. The floor slab base rock should be crushed rock or crushed gravel and sand meeting the requirements outlined in the "Structural Fill" section of this report. The imported granular material should be placed in one lift and compacted to not less than G EODESIGN= 12 Polygon-124-01:120514 95 percent of the maximum dry density, as determined by ASTM D 1557. Floor slab base rock contaminated with excessive fines (greater than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve) should be replaced. Settlement of floor slabs supporting the anticipated design loads and constructed as recommended is not expected to exceed approximately Y2 inch. Flooring manufacturers often require vapor barriers to protect flooring and flooring adhesives. Many flooring manufacturers will warrant their product only if a vapor barrier is installed according to their recommendations. Selection and design of an appropriate vapor barrier, if needed, should be based on discussions among members of the design team. We can provide additional information to assist you with your decision. 5.10 RESISTANCE TO SLIDING Lateral loads on footings can be resisted by passive earth pressure on the sides of the structures and by friction on the base of the footings. Our analysis indicates that the available passive earth pressure for footings confined by structural fill or footings constructed in direct contact with the undisturbed native soil or structural fill is 350 pcf. Typically, the movement required to develop the available passive resistance may be relatively large; therefore,we recommend using a reduced passive pressure of 250 pcf. Adjacent floor slabs, pavements, or the upper 12-inch depth of adjacent unpaved areas should not be considered when calculating passive resistance. A coefficient of friction equal to 0.35 may be used when calculating resistance to sliding. The passive earth pressure and friction components may be combined, provided that the passive component does not exceed two-thirds of the total. 5.11 RETAINING STRUCTURES 5.11.1 Assumptions Our retaining wall design recommendations are based on the following assumptions: (1)the walls consist of conventional, cantilevered retaining walls, (2)the walls are less than 12 feet in height, (3)the backfill is drained and consists of imported granular material, and (4)the backfill has a slope flatter than 4H:1 V. Re-evaluation of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. 5.112 Wall Design Parameters For unrestrained retaining walls, an active pressure of 35 pcf equivalent fluid pressure should be used for design. For embedded building walls, a superimposed seismic lateral force should be calculated based on a dynamic force of 6H2 pounds per lineal foot of wall (where H is the height of the wall in feet). The load should be applied as a distributed load with the centroid located at a distance of 0.6H from the base of the wall. Where retaining walls (such as basement stem walls) are restrained from rotation prior to being backfilled, a pressure of 55 pcf equivalent fluid pressure should be used for design. If surcharges (e.g., retained slopes, building foundations, vehicles, steep slopes, terraced walls, etc.)are located within a horizontal distance from the back of a wall equal to the height of the CEO DESIGN= 13 Polygon-124-01:120514 wall, then additional pressures will need to be accounted for in the wall design. Our office should be contacted for appropriate wall surcharges based on the actual magnitude and configuration of the applied loads. The base of the wall footing excavations should extend a minimum of 18 inches below the lowest adjacent grade. The wall footings should be designed in accordance with the guidelines provided in the appropriate portion of the "Shallow Foundations" section of this report. 5.11.3 Wall Drainage and Backfill The above design parameters have been provided assuming that drains will be installed behind the walls to prevent buildup of hydrostatic pressures. If a drainage system is not installed, then our office should be contacted for revised design forces. Backfill material placed behind retaining walls and extending a horizontal distance of%H (where H is the height of the retaining wall) should consist of imported granular material meeting the requirements described in the "Structural Fill" section of this report. Alternatively, the native soil can be used as backfill material provided a minimum 2-foot-wide column of angular drain rock wrapped in a drainage geotextile is placed against the wall and the native soil can be adequately moisture conditioned for compaction. The rock column should extend from the perforated drainpipe or foundation drains to within approximately 1 foot of the ground surface. The angular drain rock and drainage geotextile for walls should meet the requirements provided in the "Structural Fill" section of this report. Perforated collector pipes should be placed at the base of the granular backfill behind the walls. The pipe should be embedded in a minimum 2-foot-wide zone of angular drain rock wrapped in a drainage geotextile fabric. The collector pipes should discharge at an appropriate location away from the base of the wall. Unless measures are taken to prevent backflow into the wall's drainage system, the discharge pipe should not be tied directly into stormwater drain systems. Backfill should be placed and compacted as recommended for structural fill, with the exception of backfill placed immediately adjacent to walls. Backfill adjacent to walls should be compacted to a lesser standard to reduce the potential for compaction-induced earth pressures on the walls. Backfill located within a horizontal distance of 3 feet from the retaining walls should be compacted to approximately 90 percent of the maximum dry density, as determined by ASTM D 1557. Backfill placed within 3 feet of the wall should be compacted in lifts less than 6 inches thick using hand-operated tamping equipment(such as a jumping jack or vibratory plate compactor). If flatwork(such as slabs, sidewalk, or pavement)will be placed adjacent to the wall, we recommend that the upper 2 feet of fill be compacted to 95 percent of the maximum dry density, as determined by ASTM D 1557. Settlement of up to 1 percent of the wall height commonly occurs immediately adjacent to the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend that construction of flatwork adjacent to retaining walls be postponed at least four weeks after construction, unless survey data indicates that settlement is complete prior to that time. �i EO DESIGN= 14 Polygon-124-01:120514 5.12 SEISMIC CONSIDERATIONS Based on our investigation, it is our opinion that the site is unlikely to be affected by seismic hazards (such as liquefaction, ground settlement, or ground rupture). Seismic design criteria in accordance with the 2012 IBC are summarized in Table 1. Table 1. Seismic Design Parameters Parameter Short Period 1 Second Period (TS=0.2 second) (T1 = 1.0 second) MCE Spectral Acceleration, S SS= 0.95 g S, =0.42 g Seismic Site Class D Site Coefficient, F Fa= 1.12 F = 1.58 Adjusted Spectral Acceleration, SM SMs= 1.07 g SM, = 0.67 g Design Spectral Response S�= 0.71 g Spy = 0.45 g Acceleration Parameters, Sp Design Spectral PGA 0.28 g Liquefaction is caused by a rapid increase in pore water pressure that reduces the effective stress between soil particles to near zero. Granular soil, which relies on interparticle friction for strength, is susceptible to liquefaction until the excess pore pressures can dissipate. In general, loose, saturated sand soil with low silt and clay content is the most susceptible to liquefaction. Saturated silty soil with low or no plasticity is moderately susceptible to liquefaction under relatively higher levels of ground shaking. Based on the silt and clay soil and depth to groundwater at the site, it is our opinion that the risk of liquefaction under design levels of ground shaking is low at this site. 5.13 PAVEMENT DESIGN RECOMMENDATIONS New pavement should be constructed on competent subgrade or new engineered fill prepared in conformance with the "Site Preparation"and "Structural Fill" sections of this report. We do not have specific information on the frequency and type of vehicles expected at the site. Based on our experience with similar projects,we anticipate that traffic will likely consist of no more than 10 trucks (two to three axles) per day. If the traffic scenario and the following design assumptions are incorrect, please contact us for revised pavement recommendations. Our pavement recommendations are based on the following assumptions: • A resilient modulus of 20,000 psi was estimated for the aggregate base. • A resilient modulus of 3,700 psi was estimated for the subgrade. • Initial and terminal serviceability indices of 4.2 and 2.5, respectively. • Reliability and standard deviations of 75 percent and 0.45, respectively. • Structural coefficients of 0.42 and 0.14 for the asphalt and aggregate base, respectively. G EODESIGNZ 15 Polygon-124-01:120514 • The design life of the pavement is 20 years. Zero growth over the design life. • Trucks will have two to three axles. If any of these assumptions vary from project design values, our office should be contacted with the appropriate information so that the pavement designs can be revised. Our pavement design recommendations and assumed traffic scenarios are summarized in Table 2. The design team should select the most appropriate design traffic level. This may vary for different roads within the development. Table 2. Pavement Section Thickness Pavement Section Pavement Section Traffic Levels Thicknesses on Thicknesses on On-Site Subgrade' Cement-Amended Subgrade2 (inches) (inches) Cars/Day Trucks/Day AC Base Rock AC Base Rock 250 0 2.5 8.0 2.5 4.0 250 5 3.0 8.0 3.0 4.0 250 10 3.0 10.0 3.0 4.0 1. All thicknesses are intended to be the minimum acceptable values. 2. Compressive strength of cement-amended soil should be at least 100 psi. The AC should be Level 2, 'A-inch, dense MHMAC according to OSSC 00744 (Minor Hot Mixed Asphalt Concrete)and compacted to 91 percent of the maximum specific gravity of the mix, as determined by AASHTO T 209. Minimum lift thickness for%-inch MHMAC is 2.0 inches. Asphalt binder should be performance graded and conform to PG 64-22. The aggregate base should meet the specifications and be placed as recommended for pavement base rock in the "Structural Fill" section of this report. Aggregate base contaminated with soil during construction should be removed and replaced before paving. The design is for planned traffic and is not intended for heavy construction traffic. If heavy construction traffic will be allowed on newly installed asphalt, we can be contacted to provide recommended sections that include the anticipated construction loading. 6.0 OBSERVATION OF CONSTRUCTION Satisfactory earthwork and foundation performance depends to a large degree on the quality of construction. Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect whether subsurface conditions change significantly from those anticipated. In addition, sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. C EO DESIGN= 16 Polygon-124-01:120514 7.0 LIMITATIONS We have prepared this report for use by Polygon Northwest Company and members of their design and construction teams for the proposed project. The data and report can be used for estimating purposes, but our report, conclusions, and interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Soil explorations indicate soil conditions only at specific locations and only to the depths penetrated. The soil explorations do not necessarily reflect soil strata or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during the course of excavation and construction, re-evaluation will be necessary. The site development plans and design details were not finalized at the time this report was prepared. When the design has been finalized and if there are changes in the site grades or location, configuration, design loads, or type of construction for the buildings, the conclusions and recommendations presented may not be applicable. If design changes are made,we should be retained to review our conclusions and recommendations and to provide a written evaluation or modification. 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. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with the generally accepted practices in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. ♦ ♦ ♦ G EODESIGNi 17 Polygon-124-01:120514 We appreciate the opportunity to be of continued service to you. Please call if you have questions concerning this report or if we can provide additional services. Sincerely, ��vkEp PR Opp G e .,,_Inc. t 4�� e<, 4)1 NFF,Asoy /� )7 -1 _ At63114PE T. OFI=GON 'r ZOO awn M. Dimke, P.E., G.E. s '°n 14, Associate Engineer '74wN 0\Mi- J� EXPIRES: 12/31/15 Signed for Scott V. Mills, P.E., G.E. Principal Engineer Ci EODESIGN? 18 Polygon-124-01:120514 N W CC z V cc Printed By:aday I Print Date:12/3/2014 8:12:02 AM File Name: J:\M-R\Polygon\Polygon-124\Polygon-124-01\Figures\CAD\Polygon-124-01-VM01.dwg I Layout:FIGURE 1 I r, x 0 mn � , Adm —I _ -a � ' 10 -1m C") O > p 0 oZ ®mp t�,: � a C] � o INC Z ., D Pa m O 7O 3 T v 0 p m3 �� w m Z , rk, m 7� F A N N " 4� P r ✓ • 5 �pb CKyy, 34� 6 O.', __ _ '_ _ ---_ _SW„Roy Rogers -Rd w ' w f 1. � r E t. z , l I ' o O > _ -I j— < 3 m E �O i .. ' z -_- " ` O o Z X O , i m -oo r- ��� 0 ; _ A \"' X 0 Z W a a Q APPENDIX FIELD EXPLORATIONS GENERAL We explored subsurface conditions in the project area by excavating 12 test pits (TP-1 through TP-12)to depths ranging between 9.0 and 15.0 feet BGS at the approximate locations shown on Figure 2. Excavation services were provided by Dan J. Fischer Excavating, Inc. using a John Deere 310e backhoe on November 12, 2014. A member of our geotechnical staff observed the explorations. Exploration logs are included in this appendix. Except for test pit TP-8, the locations of the explorations were surveyed by Pacific Community Design. The location of test pit TP-8 was estimated by pacing from existing site features. Elevations on the exploration logs were interpreted from the topographic contours shown on Figure 2. This information should be considered accurate to the degree implied by the methods used. SOIL SAMPLING Representative grab samples of the soil observed in the test pit explorations were obtained from the walls and/or base of the test pits using the excavator bucket. SOIL CLASSIFICATION The soil samples were classified in accordance with the "Exploration Key" (Table A-1)and "Soil Classification System"(Table A-2), which are included in this appendix. The logs indicate the depths at which the soils or their characteristics change, although the change could be gradual. If the change occurred between sample locations, the depth was interpreted. Classifications and sampling intervals are presented on the exploration logs included in this appendix. LABORATORY TESTING CLASSIFICATION The soil samples were classified in the laboratory to confirm field classifications. The laboratory classifications are presented on the exploration logs if those classifications differed from the field classifications. MOISTURE CONTENT We determined the natural moisture content of selected soil samples in general accordance with ASTM D 2216. The natural moisture content is a ratio of the weight of the water to the dry weight of soil in a test sample and is expressed as a percentage. The moisture contents are presented in this appendix. ATTERBERG LIMITS The plastic limit and liquid limit(Atterberg limits)of selected soil samples were determined in accordance with ASTM D 4318. The Atterberg limits and the plasticity index were completed to aid in the classification of the soil. Results of the Atterberg limits testing are presented in this appendix. G Eo DESIGNS A-1 Polygon-124-01:120514 GRAIN-SIZE TESTING Fines content determinations were completed on selected samples in general accordance with ASTM D 1140 (percent passing the U.S. Standard No. 200 Sieve). The results of the fines content determinations are presented in this appendix. G EODESIGN= A-2 Polygon-124-01:120514 SYMBOL SAMPLING DESCRIPTION ill Location of sample obtained in general accordance with ASTM D 1586 Standard Penetration Test with recovery Location of sample obtained using thin-wall Shelby tube or Geoprobe® sampler in general accordance with ASTM D 1587 with recovery Location of sample obtained using Dames & Moore sampler and 300-pound hammer or pushed with recovery Location of sample obtained using Dames & Moore and 140-pound hammer or pushed with recovery N Location of sample obtained using 3-inch-O.D. California split-spoon sampler and 140-pound hammer NLocation of grab sample Graphic Log of Soil and Rock Types c::.? Observed contact between soil or Rock coring interval i,:;�? V rock units (at depth indicated) Water level during drilling Inferred contact between soil or rock units (at approximate depths indicated) T Water level taken on date shown ' •. ' — GEOTECHNICAL TESTING EXPLANATIONS ATT Atterberg Limits PP Pocket Penetrometer CBR California Bearing Ratio P200 Percent Passing U.S. Standard No. 200 CON Consolidation Sieve DD Dry Density RES Resilient Modulus DS Direct Shear SIEV Sieve Gradation HYD Hydrometer Gradation TOR Torvane MC Moisture Content UC Unconfined Compressive Strength MD Moisture-Density Relationship VS Vane Shear OC Organic Content kPa Kilopascal P Pushed Sample ENVIRONMENTAL TESTING EXPLANATIONS CA Sample Submitted for Chemical Analysis ND Not Detected P Pushed Sample NS No Visible Sheen PID Photoionization Detector Headspace SS Slight Sheen Analysis MS Moderate Sheen ppm Parts per Million HS Heavy Sheen G ? EXPLORATION KEY TABLE A-1 1557575 P Suite 9N Sequoia Parkway-Suite 100 Portland OR 97224 Off 503.968.8787 fax 503.968.3068 RELATIVE DENSITY-COARSE-GRAINED SOILS Relative Density Standard Penetration Dames&Moore Sampler Dames&Moore Sampler Resistance (140-pound hammer) (300-pound hammer) Very Loose 0-4 0- 11 0-4 Loose 4- 10 11 -26 4- 10 Medium Dense 10- 30 26- 74 10-30 Dense 30- 50 74- 120 30-47 Very Dense More than 50 More than 120 More than 47 CONSISTENCY - FINE-GRAINED SOILS Consistency Standard Penetration Dames&Moore Sampler Dames&Moore Sampler Unconfined Compressive Resistance (140-pound hammer) (300-pound hammer) Strength(tsf) Very Soft Less than 2 Less than 3 Less than 2 Less than 0.25 Soft 2 -4 3 -6 2 - 5 0.25 -0.50 Medium Stiff 4-8 6- 12 5 -9 0.50- 1.0 Stiff 8- 15 12 -25 9- 19 1.0-2.0 Very Stiff 15 -30 25 -65 19- 31 2.0-4.0 Hard More than 30 More than 65 More than 31 More than 4.0 PRIMARY SOIL DIVISIONS GROUP SYMBOL GROUP NAME CLEAN GRAVELS GW or GP GRAVEL GRAVEL (< 5%fines) (more than 50%of GRAVEL WITH FINES GW-GM or GP-GM GRAVEL with silt coarse fraction ( 5%and_< 12%fines) GW GC or GP GC GRAVEL with clay COARSE-GRAINED retained on GM silty GRAVEL No.4 sieve) GRAVELS WITH FINES SOILS (> 12%fines) GC clayey GRAVEL (more than 50% GC-GM silty,clayey GRAVEL CLEAN SANDS retained on SAND (<5%fines) SW or SP SAND No. 200 sieve) (50%or more of SANDS WITH FINES SW-SM or SP-SM SAND with silt coarse fraction ( 5%and 5 12%fines) SW SC or SP SC SAND with clay passing SANDS WITH FINES SM silty SAND No.4 sieve) SC clayey SAND (> 12%fines) SC-SM silty,clayey SAND ML SILT FINE-GRAINED CL CLAY SOILS Liquid limit less than 50 CL-ML silty CLAY (50%or more SILT AND CLAY OL ORGANIC SILT or ORGANIC CLAY passing Liquid limit 50 or MH SILT No. 200 sieve) greater CH CLAY OH ORGANIC SILT or ORGANIC CLAY HIGHLY ORGANIC SOILS PT PEAT MOISTURE ADDITIONAL CONSTITUENTS CLASSIFICATION Secondary granular components or other materials Term Field Test such as organics,man-made debris,etc. Silt and Clay In: Sand and Gravel In: very low moisture, Percent Fine-Grained Coarse- Percent Fine-Grained Coarse- dry dry to touch Soils Grained Soils Soils Grained Soils moist damp,without < 5 trace trace < 5 trace trace visible moisture 5 - 12 minor with 5 - 15 minor minor wet visible free water, > 12 some silty/clayey 15 - 30 with with usually saturated > 30 sandy/gravelly Indicate% G EoDESIGN? SOIL CLASSIFICATION SYSTEM TABLE A-2 15575 SW Sequoia Parkway-Suite 100 Portland OR 97224 Off 503.968.8787 Fax 503.9683068 0 O= u w DEPTH u j.- a H a •MOISTURE MATERIAL DESCRIPTION w COMMENTS FEET J p < CONTENT% LU —0.0---- 295.0 Medium stiff, brown SILT(ML), trace 0 50 100 sand and organics; moist, sand is fine (12-inch-thick tilled zone, 3-inch-thick 294.0 root zone). f 1.oX Medium stiff, brown SILT(ML),trace PP PP=0.75 tsf sand and clay; moist, sand is fine. 2.5— PP X • PP= 1.0 tsf very stiff at 3.5 feet PP PP=3.0 tsf x 5.0— 7.5— X 10.0— dark brown at 10.0 feet X • Y 12.5— C 281.5 Dense, brown, silty SAND (SM),trace 13.5 gravel and clay; moist (decomposed o _ basalt). I- Z 280 15.0 Exploration completed at a depth of 15.0 x • No groundwater seepage observed to the depth explored. 0 15.0 feet. No caving observed to the depth z explored. u u�l 0 0 w — U u 17.5— N 1 — 17 a NN Z _ 0 u 20.0 0 50 100 a w L.7 EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 uJ W 0. EXCAVATION METHOD:backhoe(see document text) ° G EODESIGNu POLYGON-124-01 TEST PIT TP-1 I- 15575 SW Sequoia Parkway-Suite 100— and 224 WOff 503.96881787OR 897503.968.3068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-1 0 oz u w DEPTH v Q„ a •MOISTURE FEET MATERIAL DESCRIPTION >w CONTENT% COMMENTS u w 281.0 0 50 100 —0.0 Soft, brown CLAY(CL), some silt,trace to minor organics, trace sand; moist, sand is fine (6-inch-thick root zone) - / FILL. PP X • PP=0.25 tsf trace gravel at 2.0 feet PP PP=0.5 tsf 2.5—j pp PP=0.75 tsf PP=2.0 tsf stiff at 3.0 feet ATT X • LL=34% PP PL=21% 5.0�/ 275.5 Stiff, brown SILT(ML), minor sand; 5.5 moist. 7.5— 10.0— with cobbles (up to 6-inch diameter)at 10.5 feet 12.5— P200 X • P200=93% c N W 267.0 F- Exploration completed at a depth of 14.0 No groundwater seepage observed 14.0 feet. No caving observed to the depth 15.0— explored. 0 u z 0 0 w - U 17.5— N I O r. N z _ O U O 20.0 0 50 100 a a EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 Ui w d EXCAVATION METHOD:backhoe(see document text) GEODESIGNPOLYGON-124-01 TEST PIT TP-2 o I_ 15575 SW Sequoia Parkway-Suite 100 Off 503.968.8787d OR 97224 224.968.3068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-2 • Z O O= U w DEPTH u Q a 2 •MOISTURE COMMENTS MATERIAL DESCRIPTION w FEET J p CONTENT HLLJ —0.0--- 298.0 0 50 100 Soft to medium stiff, brown SILT(ML), trace sand, organics, and gravel; moist, sand is fine (10-inch-thick tilled zone, 3- 297.0 inch-thick root zone). ` 1.0 PP X PP=0.75 tsf Stiff to very stiff, light brown SILT(ML), minor sand,trace clay and gravel; moist, sand is fine. 2.5— X • PP= 1.0 tsf PP PP= 2.0 tsf pp PP= 3.5 tsf 5.0— with cobbles (3-to 6-inch diameter) at X 6.0 feet 7.5— 289.5 amo Dense, red brown, silty GRAVEL with 8.5 X • o.6) cobbles (GM); moist (decomposed Jomc2 basalt). 10.0- o° Moderate groundwater seepage 00o with cobbles and boulders at 10.5 feet observed at 10.5 feet. o>s 287.0 Exploration terminated at a depth of 11.0 1 1.0 feet due to refusal. No caving observed to the depth explored. - 12.5— hev O I— z E2. 15.0- 1- 0 ✓ _ 17, 0 z 0 O W - V u 17.5— 1 O z - 0 V • 20.0 2 0 50 100 W EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 W d EXCAVATION METHOD:backhoe(see document text) ° POLYGON-124-01 TEST PIT TP-3 • G EODESIGN� • 15575 SW Sequoia Parkway-Suite 100 Portland OR 97224 BULL MOUNTAIN III FIGURE A-3 ..• Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 TIGARD,OR Z p -r 1.1.1 DEPTH u Q a N •MOISTURE = MATERIAL DESCRIPTION ,. .,1-8s1 < CONTENT% COMMENTS FEET u LU —0.0 266.0 0 50 100 Medium stiff, brown SILT(ML), trace clay and organics; moist (14-inch-thick tilled zone, 5-inch-thick root zone). 264.8 Medium stiff to stiff, brown SILT(ML), 1.2 • PP X PP=0.75 tsf trace sand; moist, sand is fine. 2.5— pp PP= 1.25 tsf X pp PP= 1.5 tsf 5.0— very stiff,with sand at 5.0 feet • 7.5 10.0— ▪ 12.5ko — N W _ with cobbles at 14.0 feet 251.5 14.5 No groundwater seepage observed Exploration completed at a depth of to the depth explored. 15.0— 14.5 feet. No caving observed to the depth explored. a V Z W 0 0 W - u • 17.5— N 17 a- v _ Z 0 V 2• 20.0 50 100 W EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a ec a. a. EXCAVATION METHOD:backhoe(see document text) ▪ G EODESIGNPOLYGON-124-01 TEST PIT TP-4 Nu F- 15575 SW Sequoia Parkway-Suite 100 vl Portland OR 97224 BULL MOUNTAIN III ILL' Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 FIGURE A-4 TIGARD,OR Z o O= Z w 1- DEPTH a MATERIAL DESCRIPTION >0 Q •ONTIENTR°/E COMMENTS LJ I— N l7 254.0 0 50 100 —0.0 Stiff, brown SILT(ML), minor organics, trace sand; moist, sand is fine (15-inch- thick tilled zone, 5-inch-thick root zone). 252.7 —\Stiff, brown with gray mottled SILT(ML), 1'3 PP PP= 1.75 tsf trace sand and clay; moist, sand is fine. 2.5— PP PP=2.0 tsf PP PP= 1.5 tsf Drainpipe at 3.5 feet. X • 5.0— 7.5- X Slow groundwater seepage observed at 8.0 feet. Minor caving observed at 8.0 feet. 10.0— Y 12.5— N F 239.5 Z Exploration completed at a depth of la.s X • 15.0— 14.5 feet. I- 0 z u w 0 0 w - V c7 17.5— N a. z 0 u 20.0 0 0 50 100 a w EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a. Ui a. EXCAVATION METHOD:backhoe(see document text) ° POLYGON-124-01 TEST PIT TP-5 G EODESIGNZ 15575 SW Sequoia Parkway-Suite 100 In Portland OR 97224 BULL MOUNTAIN If F Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 FIGURE A-5 TIGARD,OR Z O om U w DEPTH Q a H •MOISTURE FEET MATERIAL DESCRIPTION J o < CONTENT% COMMENTS U 0 50 100 —0.0 268.0 Medium stiff, brown SILT(ML), minor organics; moist (12-inch-thick tilled zone, 5-inch-thick root zone). 267.0 Medium stiff to stiff, gray-brown SILT ''0 PP • PP= 1.0 tsf (ML), trace clay and organics; moist. X 2.5— pp PP=2.0 tsf pp PP=2.25 tsf 5.0— X • 7.5— 10.0— Slow groundwater seepage observed at 11.0 feet. 256.5 Hard, red-brown SILT with gravel (ML); 11.5 moist (decomposed basalt). X 255.5 • No caving observed to the depth 12.5 Exploration terminated at a depth of 12.5 explored. 12.5 feet due to refusal. N I- z d 15.0— 1- 0 aV _ Z of _ O w - U 8 17.5— (Ni 0 v _ Z O U O 20.0 0 50 100 a U EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 d a EXCAVATION METHOD:backhoe(see document text) POLYGON-124-01 TEST PIT TP-6 G EODESIGNu 15575 SW Sequoia Parkway-Suite 100 Portland OR 97224 BULL MOUNTAIN III - Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 FIGURE A-6 TIGARD,OR u Z o O= L w DEPTH u Q p., F a •MOISTURE MATERIAL DESCRIPTION w COMMENTS FEET J p N CONTENT% —0.0 284.0 0 50 100 Medium stiff, brown SILT(ML), minor organics, trace clay; moist (10-inch-thick tilled zone, 4-inch-thick root zone). 283.0 Medium stiff to stiff, brown SILT(ML), 1'0 pp A PP= 1.25 tsf trace clay and sand; moist, sand is fine. pp PP= 1.0 tsf 2.5— PP X • PP=2.0 tsf 5.0— with sand at 7.0 feet X 7.5— 10.0— Y 12.5 X 271.5 Exploration completed at a depth of 12.5 • No groundwater seepage observed 12.5 feet. to the depth explored. No caving observed to the depth explored. IJ I- z ii 15.0— I- U _ z u�l 0 0 w - V u 17.5— 1 17 I - d N Z 0 V 20.0 a 0 50 100 w EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a or w o. EXCAVATION METHOD:backhoe(see document text) V G EO DES I G NZ POLYGON-124-01 TEST PIT TP-7 15575 SW Sequoia Parkway-Suite 100 Off 503.96851787 and OR Fax7224 503.9683068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-7 • Z O 0= uze DEPTH u Q 2 •MOISTURE COMMENTS MATERIAL DESCRIPTION >''' In CONTENT FEET –J p H N w 0 50 100 —0.0-- 315.0 Stiff, brown, gravelly SILT with concrete and brick debris (ML),trace organics; moist (4-inch-thick root zone)- FILL. 313.0 PP X • PP= 1.5 tsf Medium stiff to stiff, brown SILT(ML), 2.0 2.5— minor sand; moist to wet, sand is fine. PP X PP=0.75 tsf stiff to very stiff at 4.0 feet PP PP=2.25 tsf 5.0— 7.5— g • 10.0— 303.5 Hard, brown SILT with cobbles and 11.5 gravel (ML); moist, cobbles are up to 6- 12 5 inch diameter(decomposed basalt). 302.5 Exploration terminated at a12.5 depth ofNo groundwater seepage observed p to the depth explored. ry 12.5 feet due to refusal. No caving observed to the depth explored. w _ 0 z E 15.0— I- 0 V _ z vt _ 0 O w – u u 17.5— ni 0 4 Z – 0 V 0 20.0 0 50 100 w EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 cc a. EXCAVATION METHOD:backhoe(see document text) POLYGON-124-01 TEST PIT TP-8 G EODESIGNZ F 15575 SW Sequoia Parkway-Suite 100 Portland OR 97224 BULL MOUNTAIN III – Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 FIGURE A-8 TIGARD,OR Z o o= u DEPTH u Q H d •MOISTURE FEET MATERIAL DESCRIPTION >w to CONTENT% COMMENTS -J ~ N u 0 50 100 Medium stiff to stiff, brown SILT(ML), 325.0 _ trace organics, clay and sand; moist, sand is fine (14-inch-thick tilled zone, 5- \inch-thick root zone). F a�2$ X Medium stiff to stiff, brown SILT(ML), minor sand, trace clay; moist, sand is PP PP=0.75 tsf fine. 2.5— pp PP= 1.0 tsf stiff to very stiff at 3.0 feet X • PP PP=2.5 tsf 5.0— X 7.5 317.5 Hard, red-brown gravelly SILT with 7.5 cobbles (ML); moist, cobbles are up to 10-inch diameter(decomposed basalt). 1 s.7 Exploration terminated at a depth of 9.3 x • No groundwater seepage observed 9.3 feet due to refusal. /� to the depth explored. 10.0— No caving observed to the depth explored. Y 12.5— v N l] _ z Z K2_ 1 5.0— H 0 az W 0 L W u u 17.5— 1 a- N z _ 0 V o 20 0 0 50 100 W EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a LU W a EXCAVATION METHOD:backhoe(see document text) 8POLYGON-124-01 TEST PIT TP-9 G EODESIGNZ 15575 SW Sequoia Parkway-Suite 100 Off 503.9Potland andOR97224 503.968.3068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-9 u z = u DEPTH U a H •MOISTURE x MATERIAL DESCRIPTION w COMMENTS FEET J p w < CONTENT% u w 294.0 0 50 100 —0.0 Medium stiff, brown SILT(ML), trace sand and organics; moist, sand is fine (14-inch-thick tilled zone, 3-inch-thick \root zone). F 29 2$ Medium stiff to stiff, brown with gray • mottled SILT(ML), minor sand, trace 2.5— clay; moist, sand is fine. PP X PP= 1.25 tsf stiff to very stiff at 4.0 feet PP PP=2.75 tsf 5.0 X • 7.5— 284.0 10.0 O Dense, brown, silty GRAVEL with 10.0 '6°'t X00° cobbles (GM); moist (decomposed ,o)� basalt). 283.0 Slow groundwater seepage Exploration terminated at a depth of "'0 X • observed at 11.0 feet. 11.0 feet due to refusal. No caving observed to the depth explored. i- 12.5— v c z -L E2_ 15.0— F - O z U In _ O w - u 17.5— N I — O N Z 0 u 2. 20.0 0 50 100 EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a. d EXCAVATION METHOD:backhoe(see document text) u G EODESIGNZ POLYGON-124-01 TEST PIT TP-10 15575 SW Sequoia Parkway-Suite 100 Off 503.9P rdandand OR97224 4.968.3068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-10 • Z 0 0= u J DEPTH Q b •MOISTURE x MATERIAL DESCRIPTION w COMMENTS FEET 5 J p tQ CONTENT% w 283.0 0 50 100 —0' Soft, brown SILT(ML), minor clay and organics; moist to wet(14-inch-thick tilled zone, 5-inch-thick root zone). Medium stiff to stiff, gray brown CLAY 281.8X 1.2 • (CL), minor silt; moist to wet. PP PP= 1.25 tsf PP PP= 1.75 tsf 2.5 stiff to very stiff at 2.5 feet PP= 3.75 tsf ATT X • LL=41% PP PL=21% 5.0 J/ 2775 Very stiff, brown with gray mottled, 5.5 = sandy SILT(ML),trace clay; moist. x 7.5— Moderate groundwater seepage wet at 8.0 feet observed at 8.0 feet. 10.0— 1- 12.5— le1 269.5 Exploration completed at a depth of 13.5 • - 13.5 feet. No caving observed to the depth explored. I- z IT_ 15.0— I- 0 u z i0 0 0 w - u v 17.5— N a- N Z 0 u 2 20.0 0 50 100 EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 a. Ui W a EXCAVATION METHOD:backhoe(see document text) ° u POLYGON-124-01 TEST PIT TP-11 GEODESIGN� 15575 SW Sequoia Parkway-Suite 100 Off 503.968.8787 Portland OR a97224 503.968.3068 BULL MOUNTAIN III DECEMBER 2014 TIGARD,OR FIGURE A-11 Z 0 0= u w DEPTH u Q a Ll •MOISTURE FEET 5 MATERIAL DESCRIPTION J H N CONTENT% COMMENTS u w 298 0 0 50 100 —o.o Soft to medium stiff, brown SILT(ML), minor organics; moist(14-inch-thick tilled zone, 6-inch-thick root zone). 296.8 Medium stiff to stiff, brown with gray 1.2 mottled SILT(ML),trace sand and clay; pp X PP= 1.0 tsf moist, sand is fine. 2.5— • pp • PP= 1.5 tsf stiff to very stiff at 3.5 feet pp PP=2.75 tsf 5.0— 292.0 Excavated around boulders, immovable with excavator at 6.0 so4) Dense, brown, silty GRAVEL with 6.0 X • feet. boulders (GM); moist (decomposed o) –o)< basalt). pm:� CJS 7.5—40>c k. QD< with cobbles and boulders at 8.5 feet 289.0 Exploration terminated at a depth of 9 9.0 xNo groundwater seepage observed 9.0 feet due to refusal. to the depth explored. No caving observed to the depth 1 o.o— explored. - 12.5— v p4 N O _ I- Z a 15.0— I- 0 u _ z 0 w u u 17.5— N ^I _ a 1- 0 N Z _ 0 u o 20'0 0 50 100 a EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:REK COMPLETED:11/12/14 d EXCAVATION METHOD:backhoe(see document text) POLYGON-124-01 TEST PIT TP-12 ▪ G E0 DESIGN 15575 SW Sequoia Parkway-Suite 100— Portland OR 97224 BULL MOUNTAIN III -• Off 503.968.8787 Fax 503.968.3068 DECEMBER 2014 FIGURE A-12 TIGARD,OR 60 50 CH or OH "A" LINE X 40 W 0 30 H CL or OL aJ 20 • 10 MH or OH CL ML ML or OL 0 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT Pd N KEY EXPLORATION SAMPLE DEPTH MOISTURE CONTENT LIQUID LIMIT PLASTIC LIMIT PLASTICITY INDEX Z NUMBER (FEET) (PERCENT) • TP-2 3.0 23 34 21 13 m TP-11 3.5 27 41 21 20 z u0 02 N 17 0 N N 0 0 } 0 0 a n G EODESIGNZ POLYGON-124-01 ATTERBERG LIMITS TEST RESULTS W te15575 SW Sequoia Parkway-Suite 100 BULL MOUNTAIN III Portland OR97224 DECEMBER 2014 FIGURE A-13 Off 503.968.8787 Fax 503.968.3068 TIGARD,OR SAMPLE INFORMATION SIEVE ATTERBERG LIMITS MOISTURE DRY SAMPLE CONTENT DENSITY EXPLORATION DEPTH ELEVATION (PERCENT) (PCF) GRAVEL SAND P200 LIQUID PLASTIC PLASTICITY NUMBER (FEET) (FEET) (PERCENT) (PERCENT) (PERCENT) LIMIT LIMIT INDEX TP-1 2.5 292.5 26 TP-1 10.0 285.0 29 TP-1 15.0 280.0 36 TP-2 1.5 279.5 29 TP-2 3.0 278.0 23 34 21 13 TP-2 12.0 269.0 30 93 TP-3 2.5 295.5 26 TP-3 8.5 289.5 40 TP-4 1.0 265.0 26 TP-4 7.0 259.0 31 TP-5 4.0 250.0 31 TP-5 14.5 239.5 35 TP-6 1.0 267.0 28 TP-6 6.0 262.0 36 TP-6 12.0 256.0 22 TP-7 3.0 281.0 28 TP-7 12.5 271.5 32 TP-8 1.5 313.5 32 Y v TP-8 8.0 307.0 29 N W TP-9 3.0 322.0 29 H a 0 z TP-9 9.3 315.8 21 a d TP-10 1.5 292.5 27 H a u z TP-10 6.0 288.0 33 N W o TP-10 11.0 283.0 27 LI a u TP-11 1.0 282.0 31 N f TP-11 3.5 279.5 27 41 21 20 0 4 TP-11 13.5 269.5 33 z O V } J O d 5 G EODESIGNz POLYGON-124-01 SUMMARY OF LABORATORY DATA 2 N 15575 SW Sequoia Parkway-Suite 100 Portland OR 97221 DECEMBER 2014 BULL MOUNTAIN III gOff 503.968.8787 Fax 503.968.3068 TIGARD,OR FIGURE A-14 SAMPLE INFORMATION SIEVE ATTERBERG LIMITS MOISTURE DRY EXPLORATION SAMPLE ELEVATION CONTENT DENSITY GRAVEL SAND P200 LIQUID PLASTIC PLASTICITY NUMBER DEPTH (FEET) (PERCENT) (PCF) (PERCENT) (PERCENT) (PERCENT) LIMIT LIMIT INDEX (FEET) TP-12 2.5 295.5 30 TP-12 6.0 292.0 28 l- Y l0 ❑ z Z 0. 0. 0r u z ❑ O d u a F 0 ry Z O V O d . OF LABORATORY DATA POLYGON-124-01 SUMMARY GEo ESIGNz (continued) N 15575 5Portaoia ndOR9way-7224 ite 100 DECEMBER 2014 BULL MOUNTAIN III FIGURE A-14 1''1 Portland OR 97a24 Off 503.968.8787 Fax 503.9683068 TIGARD,OR cn M >z 0 cc u Q ACRONYMS AASHTO American Association of State Highway and Transportation Officials AC asphalt concrete ASTM American Society for Testing and Materials BGS below ground surface g gravitational acceleration (32.2 feet/second2) H:V horizontal to vertical IBC International Building Code MCE maximum considered earthquake MHMAC minor hot mixed asphalt concrete OSHA Occupational Safety and Health Administration OSSC Oregon Standard Specifications for Construction (2008) OWRD Oregon Water Resources Department pcf pounds per cubic foot PG performance grade PGA peak ground acceleration psf pounds per square foot psi pounds per square inch G EO DESIGN= Polygon-124-01:120514 E O U U C a U0 C) O a) CLO 3