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Plans 1 ce _.; 1 1 GECDESIGN � u z RECEI JUL 2 6 2006 CITY OF TIGARD 1 BUILDING DIVISION 1 1 REPORT OF GEOTECHNICAL ENGINEERING SERVICES Tigard Triangle Commons Tigard, Oregon 1� 1 G o� /` ov � 7 � SW s� C 7 01? I For Pacific Northwest Properties July 19, 2005 1 GeoDesign Project: PNWP -30 -02 Engineers I Geologists I Environmental Consultants TABLE OF CONTENTS PAGE NO. 1 1.0 INTRODUCTION 1 1.1 Background 1 I 1.2 Project Understanding 1 2.0 PURPOSE AND SCOPE 2 3.0 SITE CONDITIONS 2 3.1 Surface Conditions 2 3.2 Subsurface Conditions 3 4.0 CONCLUSIONS AND RECOMMENDATIONS 4 I 4.1 General 4 4.2 Site Preparation 5 4.3 Excavation and Shoring 7 J 4.4 Erosion Control 8 4.5 Structural Fill 8 4.6 Shallow Foundations 10 I 4.7 Floor Slabs 1 1 4.8 Fill Induced Settlement 12 4.9 Rockery Retaining Structures 12 I 4.10 Conventional Retaining Structures 14 4.11 Pavement 15 4.12 Seismic Design Criteria 16 5.0 OBSERVATION OF CONSTRUCTION 17 6.0 LIMITATIONS 18 I FIGURES Vicinity Map Figure 1 Site Plan Figure 2 1 Settlement Plate Detail Figure 3 APPENDICES I Appendix A Field Exploration A -1 Laboratory Testing A -1 I Key to Test Pit and Boring Log Symbols Table A -1 Soil Classification System and Guidelines Table A -2 Rock Classification Guidelines Table A -3 1 Test Pit Logs Figure A 1 Consolidation Test Results Figure A -12 Appendix B 1 Previous Field Explorations by GeoDesign, Inc. B-1 Site Plan Exploration Logs 1 Appendix C Previous Field Explorations by GeoPacific Engineering, Inc. C -1 Exploration Logs I 1 G EODESIGN? PNWP -30- 02:071905 TABLE OF CONTENTS PAGE NO. APPENDICES continued 1 Appendix D Rockery Wall Construction D -1 Typical Rockery Section Figure D -1 Design Calculations Acronyms 1 1 1 1 1 1 1 1 1 1 1 1 1 G " EODESIGN? PNWP -30- 02:071905 1 1.0 INTRODUCTION This report presents the results of GeoDesign's geotechnical engineering evaluation of the proposed Tigard Triangle Commons to be located at the intersection of SW 67th Avenue and SW Clinton Street in Tigard, Oregon. The site relative to surrounding physical features is shown on Figure 1. The proposed site plan is presented on Figure 2 along with our exploration locations. Definitions of all acronyms used are attached at the end of this document. 1.1 BACKGROUND GEI prepared a geotechnical engineering report for the original site on March 29, 2001. The 1 original site comprised approximately the eastern half of the current site. Mr. Gene Mildren of Mildren Design Group, P.C. provided us with a copy of the report and a preliminary grading plan for the site. GEI's evaluation of the site included five test pit explorations. The explorations were completed with a small excavator (8 -ton Mitsubishi MS070). Two of the explorations encountered hard rock refusal at relatively shallow depths (5 to 6 feet BGS), while the remaining three were terminated (4.5 to 8 feet BGS) prior to encountering hard rock. GeoDesign subsequently provided additional geotechnical services for the original site. The purpose of our work was to determine the depth to hard rock in the areas of the site where deeper cuts would be constructed and the excavatability of the rock where it was encountered. A large excavator (30 -ton CAT -225) equipped with rock teeth was used to excavate our test pits. Our test pits encountered basalt bedrock between 9 and 13 feet BGS in the northeastern corner of the site. In one test pit, we were able to excavate approximately 6 feet into the weathered zone of basalt with a CAT -225 trackhoe before encountering refusal. The results of our work were presented in our September 28, 2001 report titled Geotechnical Engineering Services, Bradford Place Office Building, Tigard, Oregon. 1.2 PROJECT UNDERSTANDING Since our previous report was issued, the site layout has been revised. The location of the original building has been moved to the southeastern corner of the original site. The overall site has expanded to the west of SW 67" Avenue, to SW 68th Avenue, and north and south of SW Clinton Street. One building, a parking structure, and a detention pond have been added to the development plans. We understand that both of the buildings will consist of two -story office structures. At -grade asphalt parking lots will accompany the multi -story parking structure. We understand that maximum continuous wall loads will be 5 kips per lineal foot and maximum column Toads will be 190 kips. We have assumed that the maximum floor slab loading will be on the order of 150 psf. Cuts up to 10 feet are expected in the western portion of the site. Fills up to 18 feet are expected in the southeastern portion of the site in the building area. Retaining walls will be 1 necessary to support cuts and fills. We understand that specific wall types have not yet been determined, but will likely include rockery walls. 1 G EO DESIG N? 1 PNWP- 30- 02:071905 - i 2.0 PURPOSE AND SCOPE The purpose of our geotechnical engineering evaluation was to explore the subsurface conditions at the site and provide geotechnical engineering recommendations for design and construction. The specific scope of our services is summarized below: 1 • Coordinate and manage the field investigation, including utility locates, access preparation, rA and scheduling of contractors and GeoDesign's staff. • Complete the following subsurface exploration at the site: • Three test pits in the original site area to further evaluate soil conditions in the new building area r • Eight test pits in the added site area i • Classify the materials encountered in the test pits and maintain a detailed log of each exploration. 1 • Measure groundwater levels within explorations upon completion. • Complete laboratory analyses on disturbed and undisturbed soil samples obtained from the explorations as follows: • Twenty -one moisture content tests • Two percent fines determinations • One consolidation test to determine compressibility of the on -site soils where maximum fills are expected • Provide recommendations for site preparation, grading and drainage, stripping depths, fill type for imported materials, compaction criteria, trench excavation and backfill, use of on -site soils, and wet /dry weather earthwork. Include a discussion on rock excavation. • Provide shallow foundation recommendations for the support of building Toads. Our recommendations include allowable bearing capacity, estimated settlement, and lateral resistance. • Provide recommendations for preparation of the subgrade for floor slabs. • Recommend design criteria for retaining walls, including lateral earth pressures, backfill, compaction, and drainage. • Provide recommendations for construction of asphalt pavements for on -site access roads and parking areas, including subbase, base course, and asphalt paving thickness. • Provide recommendations for the management of identified groundwater conditions that may affect the performance of structures or pavement. • Provide settlement estimates for newly placed fill embankments. • Provide recommendations for IBC seismic coefficients. • Provide this written report summarizing our recommendations. • Prepare a rockery wall design for the project. �. 3.0 SITE CONDITIONS 1 3.1 SURFACE CONDITIONS The site is located north of the 1 -5 off -ramp exit to SW Haines Street. The site is bounded on the west by SW 68th Avenue and extends approximately 700 feet north of the 1 -5 off -ramp. 1 GEODESIGN? 2 PNWP -30- 02:071905 i - . 1 SW Clinton Street intersects the property east to west on the south side of the property and dead - ends just east of SW 64`h Avenue. The site moderately rises from the southwest to the northeast with elevation differences of approximately 25 feet. I Two existing residential dwellings are located at the north and south sides of the intersection of SW Clinton Street and SW 68th Avenue. Two footprints of previous residential dwellings or out structures that have been removed lie approximately 300 feet north of SW Clinton Street, between SW 68" and SW 67" Avenue. The site is heavily vegetated with mature deciduous and conifer trees and moderate shrubs, blackberries, and tall grasses. The site is bounded on the west by undeveloped property and SW 68`h Avenue, on the southeast by the 1 -5 off -ramp exit to 1 SW Haines Street, and on the north by an existing parking lot. 3.2 SUBSURFACE CONDITIONS 1 We explored subsurface conditions at the site by excavating 11 test pits (TP -1 through TP -1 1) to depths of 7.5 to 16.0 feet BGS. The approximate locations of the test pits are shown on Figure 2. Figure 2 also shows the approximate depth at which intact bedrock or interlocked boulders were I encountered in each test pit. Descriptions of the field explorations, test pit Togs, and laboratory procedures are included in Appendix A. Logs from the prior explorations are included in Appendices B and C. I The subsurface rofile generally consists of silt and clay to clayey gravel over basalt bedrock. I P 9 Y Y Y Y9 Some fill was encountered at the ground surface in several test pits. The clay layer represents the upper portion of the bedrock unit, which is weathered to a clay soil. The weathered bedrock zone is generally 2 to 5 feet thick and was encountered generally between 8 and 11 feet BGS. Our test I pits typically encountered refusal on boulders in the weathered basalt layer or within 1 to 2 feet of the intact bedrock surface. We encountered a 1- to 4- inch -thick root zone at the ground surface; however, deeper vegetative layers are expected in the areas of trees and shrubs. 1 We encountered fill in test pits TP -2, TP -3, TP -4, TP -7, and TP -1 1. Fill generally extends from the ground surface to a depth of 1 to 3 feet BGS. Test pit TP -2 likely encountered a backfilled test pit I from a previous exploration to a depth of 10 feet BGS. Fill material generally consists of native material with some gravel. It does not appear the fill was placed with significant compactive effort. 1 Medium stiff to very stiff, native silt unit was encountered near the ground surface or just below the fill layer. It contains small amounts of fine sand and occasional gravels to boulders. Boulders I were generally encountered deeper in the silt unit. The upper 1 to 2 feet of the silt unit has roots up to 3 inches in diameter. Based on laboratory results, the silt unit had moisture contents ranging from 19 to 30 percent at the time of our explorations. The dense to hard weathered bedrock layer was encountered below the silt unit and generally consists of clay and cobbles to boulders. Most of our test pits were able to penetrate the I weathered layer; however, some test pits encountered refusal on boulders in this layer. Based on laboratory results, the clay soil had moisture contents ranging from 24 to 34 percent at the time of our explorations. 1 1 G EODESIGN? 3 PNWP- 30- 02:071905 The basalt bedrock was encountered below the weathered zone to the maximum depth of our explorations. Where encountered, the Hitachi EX -120 trackhoe was able to excavate no more than 0.5 foot into the intact basalt bedrock unit. Our observations indicate that the basalt is slightly to moderately weathered with little fracturing. We observed slow to moderate groundwater seepage at depths between 8 and 14 feet BGS in seven of our test pits. Groundwater is likely perched on the weathered or intact basalt bedrock. The depth to groundwater is expected to fluctuate in response to seasonal changes and changes in surface topography. 4.0 CONCLUSIONS AND RECOMMENDATIONS 1 4.1 GENERAL Based on the results of our explorations, laboratory testing, and analyses, it is-our opinion that 1 the site is suitable for the proposed development. The proposed structures can be supported on shallow footings bearing on undisturbed native silt, weathered or intact basalt layer, or structural fill supported by this soil. 1 Our explorations indicate that some undocumented fill is present at the site. Strength properties of undocumented fill can be highly variable and difficult to predict. Due to the relatively unknown 1 quality of these soils, we recommend that within all building, pavement, and fill areas, the undocumented fill be removed and replaced, or scarified and compacted in accordance with the "Structural Fill" section of this report. Our specific recommendations for subgrade preparation are provided in the "Site Preparation" section of this report. Excavation in the weathered basalt zone should generally be possible with conventional earth- 1 moving equipment, although boulders present in the weathered zone may require special equipment. Excavation of the intact basalt unit will be difficult and will require special rock excavating equipment. The native, on -site silt is sensitive to small changes in moisture content and difficult, if not impossible, to adequately compact during wet weather. A more detailed discussion is presented in the "Wet Weather/Wet Soil Grading" and "Structural Fill" sections of this report. Recommendations for site winterization, if applicable, are included in the "Construction Considerations" section of this report. i Several residential structures and foundations from previous structures are present on site. Existing structures and pavements to be removed should be completely demolished and hauled off site. Resulting voids should be backfilled with structural fill. Our specific recommendations for addressing demolition are presented in the "Site Preparation" section of this report. Specific recommendations for geotechnical design and construction are provide in the following sections. i i GEODESIGN? 4 PNWP -30- 02:071905 1 4.2 SITE PREPARATION 4.2.1 Demolition Demolition will require complete removal of existing buildings, buried foundations, pavement, or other structures within areas to receive new pavements, buildings, retaining walls, or engineered 1 fills. Underground utility lines or hidden, buried tanks encountered in areas of new improvements should also be completely removed or grouted full if left in place. Materials generated during demolition should be transported off site for disposal or stockpiled in areas 1 designated by the owner. Crushed asphalt or concrete may be acceptable for use as structural fill in non - structural areas. GeoDesign can provide additional recommendations if this option is desired. Voids resulting from removal of structures or loose soil in utility lines 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. 42.2 Stripping and Grubbing Trees and shrubs should be removed from all building, fill, and pavement 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. 1 The existing topsoil zone should be stripped and removed from all proposed structural fill, pavement, and improvement areas and for a 5 -foot margin around such areas. Based on our explorations, the average depth of stripping will be approximately 1 to 4 inches. However, we expect areas where greater stripping depths will be required to remove localized zones of dense root masses or organic soil. We encountered root masses up to 24 inches BGS in some areas. The actual stripping depth should be based on field observations at the time of construction. Stripped material should be transported offsite for disposal or used in landscaped areas. 4.2.3 Uncontrolled Fill Between 1 and 3 feet of uncontrolled fill was encountered in isolated areas at the site. The fill was generally silty material with some gravel. It is unlikely that a systematic method of 1 compaction was used when the fill was placed. Accordingly, reliable strength properties are difficult to predict and there is an associated risk with supporting structural elements on the existing fill. In our opinion, and as stated in the "Shallow Foundations" and "Floor Slabs" sections of this report, the footings and floor slabs should not be supported on the existing fill. Where encountered, we recommend that the fill be completely removed down to the native silt unit within building areas. The removed material can be re -used as structural fill provided deleterious material is removed and the fill is placed and compacted as recommended in the "Structural Fill" section of this report. 1 1 G EODESIGN= 5 PNWP- 30- 02:071905 4.2.4 Subgrade Evaluation A member of our geotechnical staff should observe the exposed subgrades after stripping and site cutting have been completed to determine if there are areas of unsuitable or unstable soil. Our representative should observe a proof -roll with a fully loaded dump truck or similar heavy rubber -tire construction equipment to identify soft, loose, or unsuitable areas. Areas that appear to be too wet and soft to support proof - rolling equipment should be evaluated by probing and prepared in accordance with the recommendations for wet weather construction presented in the r following section of this report. 1 42.5 Compacting Test Pit Locations The test pit excavations were backfilled using the relatively minimal compactive effort of the 1 backhoe bucket; therefore, soft spots can be expected at these locations. We recommend that these relatively uncompacted soils be removed from the test pits to the full depth in building areas and to a depth of 3 feet below finished subgrade elevation in pavement areas. The resulting excavation should be backfilled with structural fill. 42.6 Wet Weather/Wet Soil Grading 1 The fine- grained soils at the site are easily disturbed during the wet season and when they are moist. If not carefully executed, site preparation, utility trench work, and roadway excavation can create extensive soft areas and significant subgrade repair costs can result. If construction is planned when the surficial soils are wet or may become wet, the construction methods and schedule should be carefully considered with respect to protecting the subgrade to reduce the need to over - excavate disturbed or softened soil. The project budget should reflect the recommendations below if construction is planned during wet weather or when the surficial soils are wet. If construction occurs when wet soils are present, site preparation activities may need to be accomplished using track - mounted excavating equipment that loads removed material into trucks supported on granular haul roads. 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 imported 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 be placed in one lift over the prepared, undisturbed subgrade and compacted using a smooth -drum, non - vibratory roller. Additionally, a geotextile fabric should be placed as a barrier between the subgrade and imported granular material in areas of repeated construction traffic. The imported granular material should meet the specifications in the "Structural Fill" section of this report. As an alternative to placing thick rock sections to support construction traffic, it may be possible 1 to stabilize the subgrade using a cement amendment. Cement amendment should be limited to 1 G EODESIGN= 6 PNWP -30- 02:071905 1 silty soils only. This will not be feasible in areas of deep cuts where gravel to boulders are exposed in the subgrade. If this approach is used, the cement amended soil should meet the guidelines provided in the "Structural Fill" section of this report. 4.3 EXCAVATION AND SHORING 4.3.1 Basalt Bedrock The upper 2 to 5 feet of the basalt bedrock is weathered to a conglomeration of clay and cobbles to boulders. We were generally able to excavate through the weathered zone with a Hitachi EX- 120 trackhoe with moderate effort, although we encountered refusal on boulders in some areas. All of our test pits encountered refusal in the intact basalt bedrock (see Appendix A for 1 excavation depths described in test pits logs). TP -4 encountered refusal in the bedrock at a depth of approximately 7.5 feet BGS. Excavatability was also evaluated during our prior explorations. The logs from these explorations (using a 30 -ton excavator) are in Appendix B. 1 The project grading plan indicates that site cuts up to 10 feet deep will occur in this area. Special excavation equipment, such as hydraulic breakers or rock trenchers, will likely be required to excavate the intact basalt bedrock or large boulders where our test pits encountered refusal. 4.32 Trench Cuts and Shoring Trench cuts in the silt and clay soils should stand near vertical to a depth of at least 4 feet. Open excavation techniques may be used to excavate trenches with depths between 4 and 8 feet, provided the walls of the excavation are cut at a slope of 1 H:1 V, groundwater seepage is not present, and with the understanding that some minor caving may occur. The trenches should be flattened to 1Y2H:1V if excessive caving occurs. Increased backfill volumes should be expected given the presence of boulders and bedrock soil conditions. 1 Use of a trench shield or other approved temporary shoring is recommended in the silt and clay soils where sloping is not possible. If a conventional shield is used, the contractor should limit the length of open trench. 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. All excavations should be made in accordance with applicable OSHA and state regulations. 4.3.3 Temporary Dewatering Perched groundwater may be encountered by excavations deeper than 8 feet below current site grades. Groundwater flowing into open excavations should be removed by pumping from a sump. The pump should be capable of handling variable flow rates. Water should be routed to a suitable discharge point. 4.3.4 Safety All excavations should be made in accordance with applicable OSHA and state regulations. While we have described certain approaches to the utility vault and trench excavations in the foregoing discussions, the contractor is responsible for selecting the excavation and dewatering methods, monitoring the trench excavations for safety, and providing shoring as required to protect personnel and adjacent improvements. 1 ' G EODESIGhh 7 PNWP- 30- 02:071905 - i • 4.4 EROSION CONTROL The soil at this site is eroded easily by wind and water. Therefore, erosion control measures should be planned carefully and be in place before construction begins. Erosion control plans are required on construction projects located within Washington County. Measures that can be employed to reduce erosion include the use of silt fences, hay bales, buffer zones of natural growth, sedimentation ponds, and granular haul roads. 4.5 STRUCTURAL FILL 4.5.1 General • Fills 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 1 matter or other unsuitable materials. The material should meet the specifications provided in ODOT SS 00330, depending on the application. All structural fill should have a maximum particle size of 4 inches. A brief characterization of some of the acceptable materials and our 1 recommendations for their use as structural fill is provided below. 4.52 On -Site Material 1 The on -site silt materials are suitable for use as structural fill provided they meet the requirements set forth in ODOT SS 00330.12 - Borrow Material. Clay soil and soil containing debris, cobbles, and boulders exceeding 4 inches in diameter should not be used as structural 1 fill. Based on laboratory test results, the moisture contents of the on -site silty soil are between 19 and 30 percent. Based on our experience, we estimate the optimum moisture content for compaction to be approximately 16 to 18 percent for the on -site silt; therefore, some degree of moisture conditioning (drying) will be required to use on -site, silty soil for structural fill. Accordingly, extended dry weather will be required to adequately condition the soils for use as structural fill. 1 When used as structural fill, the on -site, silty soil should be placed in lifts with a maximum uncompacted thickness of 8 inches and be compacted to not less than 92 percent of the maximum dry density, as determined by ASTM D 1557. 4.5.3 Imported Granular Material 1 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 ODOT SS 00330.14 and 00330.15. Imported granular material should be fairly well graded between coarse and fine material and have less than 5 percent by weight passing the U.S. Standard No. 200 Sieve. When used as structural fill, imported granular material should be placed in lifts with a maximum 1 uncompacted thickness of 12 inches and be compacted to not Tess than 95 percent of the maximum dry density, as determined by ASTM D 1557. 4.5.4 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 materials should have a maximum particle size of 1%2 inches, less than 5 percent by weight passing the U.S. Standard No. 200 Sieve, have at least two mechanically fractured faces, and GEODESIGN? 8 PNWP -30- 02:071905 ' I 1 should meet ODOT SS 2630.11 - Open- Graded Aggregate. 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. 4.5.5 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 ODOT SS 00641 - Aggregate Subbase, Base, and Shoulders Base Aggregate, with the exception that the aggregate have less than 5 percent passing a 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 1 12 inches and be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1 557. 4.5.6 Trench Backfill Trench backfill for the utility pipe base and pipe zone should consist of well - graded granular material with a maximum particle size of 1 inch and less than 5 percent by weight passing the U.S. Standard No. 200 Sieve and should meet ODOT SS 00405.14 - Class B Backfill. The material should be free of roots, organic matter, and other unsuitable materials. Backfill for the pipe base and pipe zone should be compacted to at least 90 percent of the maximum dry density, as 1 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 ASTM D 1 557 at depths greater than 2 feet below the finished subgrade and 95 percent of 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. 1 4.5.7 Trench Stabilization Material Trench 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 ODOT SS 00330.14 and 00330.15, with a minimum particle size of 4 inches and less than 5 percent passing the U.S. Standard No. 4 Sieve. The material should be free of organic matter and other deleterious material. Trench stabilization material should be placed in one lift and compacted to a firm condition. 4.5.8 Drain Rock ! Drain rock should consist of angular, granular material with a maximum particle size of 2 inches and should meet ODOT SS 00430.11 - Granular Drain Backfill Material. The material should be free of roots, organic matter, and other unsuitable materials and have less than 2 percent passing the U.S. Standard No. 200 Sieve (washed analysis). ' 4.5.9 Soil Amendment with Cement As an alternative to the use of imported granular material for wet - weather structural fill, an experienced contractor may be able to amend the on -site, silty soils with portland cement or with limekiln dust and portland cement to obtain suitable support properties. Successful use of soil 1 G EODESIGN? 9 PNWP- 30- 02:071905 amendment depends on the use of correct mixing techniques, soil moisture content and gradation, and amendment quantities. Soil amending should be conducted in accordance with ODOT SS 00344 - Treated Subgrade. Soil amendment will be difficult to impossible in soils containing significant quantities of clay, gravel, cobbles, and boulders. Specific recommendations, based upon 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 100 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 soils 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 1 when the soil moisture content does not exceed approximately 20 percent. If the soil moisture content is in the range of 25 to 35 percent, 4 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 1 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. 1 Portland cement - amended soils are hard and have low permeability. Therefore, these soils do not drain well, nor are they suitable for planting. Future planted areas should not be cement 1 amended, if practical, or accommodations should be planned for drainage and planting. 4.6 SHALLOW FOUNDATIONS 1 Based on the results of our subsurface explorations and analyses, it is our opinion that the proposed structures, with the anticipated design foundation loads previously described, can be supported on shallow foundations bearing on undisturbed, native soils or compacted structural fill placed on the native soil. The footings should not be founded on undocumented fill or subgrade containing excessive 1 roots. If encountered during footing preparation, these materials should be removed and the resulting excavation should be backfilled with structural fill material compacted as recommended in the "Structural Fill" section of this report. We recommend that GeoDesign observe all footing subgrade to verify that any unsuitable material encountered is adequately removed. 4.6.1 Dimensions and Capacities ' Continuous wall and isolated spread footings should be at least 16 and 20 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the lowest adjacent exterior grade. The bottom of interior footings should be established at least 12 inches below the base of the slab. Footings bearing on subgrade prepared as recommended above should be sized based on an 1 allowable bearing pressure of 3,000 psf. This is a net bearing pressure; the weight of the footing and overlying backfill can be ignored in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead plus long -term live Toads and may be increased by one -third for short-term loads such as those resulting from wind or seismic forces. 1 GEODESIGN= 10 PNWP -30- 02:071905 1 1 Based on our analysis and experience with similar soils, total post- construction settlement should 1 be Tess than 1 inch, with differential settlement of less than %z inch over a 50 -foot span. 4.6.2 Resistance to Sliding ' Lateral Toads 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 native soils and structural fills is 350 pcf modeled as an equivalent fluid pressure. 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 equivalent fluid pressure. Adjacent floor slabs, pavements, or the upper 12 -inch depth of adjacent, unpaved areas should not be considered when calculating passive resistance. Additionally, in order to rely upon passive resistance, a minimum of 10 feet of horizontal clearance must exist between the face of the footings and any adjacent down slopes. 1 For footings in contact with native soil, a coefficient of friction equal to 0.35 may be used when calculating resistance to sliding. This value may be increase to 0.40 for gravelly soils. 1 The passive and frictional resistance may be combined provided that the passive component does not exceed two - thirds of the total. These values do not include a factor of safety. We recommend a safety factor of 3 when designing for 'dead Toads plus frequently applied live loads and a safety factor of 2 be applied when considering transitory Toads such as wind and seismic forces. 4.6.3 Construction Considerations All footing and floor subgrades should be evaluated by the project geotechnical engineer or their representative to confirm suitable bearing conditions. Observations should also confirm that all loose or.soft material, organics, unsuitable fill, prior topsoil zones, and softened subgrades, if present, have been removed. Localized deepening of footing excavations may be required to penetrate any deleterious materials. If footing excavations are conducted during wet weather conditions, we recommend that a 1 minimum of 3 inches of granular material be placed and compacted until well keyed at the base of the excavations. The granular material reduces water softening of subgrade soils, reduces subgrade disturbance during placement of forms and reinforcement, and provides clean conditions for the reinforcing steel. 4.7 FLOOR SLABS Satisfactory subgrade support for building floor slabs supporting up to 150 -psf area loading can be obtained provided the building pad is prepared as described previously. To help reduce moisture transmission and slab shifting, we recommend a minimum 6- inch - thick layer of floor slab base rock be placed and compacted over a subgrade that has been prepared in conformance with the "Site Preparation" section of this report. The floor slab base rock should meet the requirements in the "Structural Fill" section of this report and be compacted to at least 95 percent 1 of ASTM D 1557. t GEODESIGN? 11 PNWP -30- 02:071905 1 The native soils are fine grained and will tend to maintain a high moisture content. The installation of a vapor barrier may be warranted in order to reduce the potential for moisture transmission through, and efflorescence growth on, the floor slabs. Additionally, flooring manufacturers often require vapor barriers to protect flooring and flooring adhesives and will warrant their product only if a vapor barrier is installed according to their recommendations. Actual selection and design of an appropriate vapor barrier, if needed, should be based on discussions among members of the design team. 1 Slabs should be reinforced according to their proposed use and per the structural engineer's recommendations. Load - bearing concrete slabs may be designed assuming a modulus of 1 subgrade reaction, k, of 125 pounds per square inch per inch. 4.8 FILL- INDUCED SETTLEMENT Large fills, up to 18 feet thick, are planned in the southeastern portion of the site. Surcharge loads from fills will result in settlement of the underlying on -site soils. Our analyses indicate that post - construction settlement will likely be less that 1 inch. 1 We recommend monitoring the settlements with a minimum of three settlement plates. A typical settlement plate detail is shown on Figure 3. For ease in handling, the casing and rod portions of the settlement plate are usually installed in 5 -foot sections. As filling progresses, couplings are used to install additional sections. Continuity in the monitoring data is maintained by reading and recording the top of the measurement rod immediately prior to and following the addition of new sections. Care must be taken during fill construction not to bend or break the rods. The settlement plates should be installed prior to site filling and immediately surveyed. Survey 1 shots should be taken at each settlement plate at least twice per week during fill construction and for at least 1 month after fill construction. The settlement plates should be monitored using survey equipment with an accuracy of 1 /100`h of a foot and referenced to a stationary datum established at least 500 feet from the edge of the surcharge area. In addition to recording the elevation of the settlement plates during each survey event, a complete record of the surcharge history requires reading and recording the fill height at each settlement plate. The survey data should be supplied to GeoDesign within 3 days of the survey. We will provide a Microsoft Excel spreadsheet to the surveyors that can be used to transfer data via email. 4.9 ROCKERY RETAINING STRUCTURES 4.9.1 General Rockeries generally act as a gravity wall to resist lateral load. Important elements of a rockery are: 1) its size, weight, and shape; 2) friction developed between individual rocks (internal friction); 3) friction between the base layer of rocks and underlying ground; 4) passive resistance to sliding developed by soil or pavement in front of the rockery; and 5) lateral load acting on or resisted by the rockery. Rockery wall construction is not an exact science and depends largely on the skill of the builder. i Although rockeries can offer significant lateral restraint, they are partially indeterminate and present some risk relative to other retaining structures when not properly constructed or GEODESIGN= 12 PNWP -30- 02:071905 1 1 designed. In addition, internal friction is very difficult to quantify and is, in part, dependent on the rock strength at the contact and again, to a large degree, on the skill and judgment of the builder. Internal friction can change over time, due to weathering of the rock and from rockery movement. Rockeries typically experience a "settling in" during and for some time after construction. Also, many rockeries are subject to an additional lateral load that causes additional movement due to wetting of the retained soil or other factors that reduce the strength of the soil. For poorly constructed marginal rockeries, movement can result in loss of internal friction and a rockery failure. 1 4.92 Assumptions Our rockery wall design recommendations are based on the following assumptions: (1) the walls are battered back no steeper than 6H:1 V, (2) the walls are no taller than 8 feet, (3) the backfill is drained and consists of imported granular materials, (4) rockery walls do not support building loads or heavy truck traffic, and (5) the backfill has a slope flatter than 5H:1 V. Re- evaluation of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. 4.9.3 Wall Construction Analyses were performed for various wall heights to determine the minimum required wall thickness and embedment depths. A surcharge of 150 psf was applied to account for light traffic loads behind the walls. We did not apply hydrostatic pressures in our design because we have recommended specific drainage requirements behind the walls. Our recommendations and calculations are included in Appendix D. A typical rockery wall section is presented in the attached Figure D -1 along with Construction Notes and a calculation package for typical wall sections. The typical rockery wall section and Construction Notes can be integrated into the project plans. As shown on Figure D -1, the minimum required wall embedment is 1 foot. The minimum wall thickness will vary with wall height as shown in the table presented on Figure D -1. The free- draining zone immediately behind the walls should consist of angular, crushed rock or gravel as described in the attached Construction Notes. 1 Perforated collector pipes should be placed at the base of the granular backfill behind the walls as shown on Figure D -1. 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. Settlements of up to 1 percent of the wall height commonly occur immediately adjacent to the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend that construction of flat work adjacent to retaining walls be postponed at least 1 4 weeks after backfilling of the wall, unless survey data indicates that settlement is complete prior to that time. 1 G EO DESIG N= 13 PNWP- 30- 02:071905 • • 4.10 CONVENTIONAL RETAINING STRUCTURES 4.10.1 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 Tess than 10 feet in height, (3) the backfill is drained and consists of imported granular materials, and (4) the backfill has a slope flatter than 4H:1V. Re- evaluation of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. Conventional walls taller than 10 feet should be designed by an engineer registered in the state of Oregon. 1 4.10.2 Wall Design Parameters For unrestrained retaining walls, an active pressure of 40 pcf equivalent fluid pressure should be used for design. For the embedded building walls, a superimposed seismic lateral force should be calculated based on a dynamic force of 6H pounds per lineal foot of wall, where H is the height of the wall in feet, and applied at 0.6H from the base of the wall. Where retaining walls are restrained from rotation prior to being backfilled, a pressure of 58 pcf equivalent fluid pressure should be used for design. If any surcharges (e. ., retained sloes, building foundations, vehicles, steep sloes, terraced Y 9 9 P 9 P P walls, etc.) are located within a horizontal distance from the back of a wall equal to twice the height of the wall, then additional pressures will need to be accounted for in the wall design. Our office should be contacted for appropriate wall surcharges based upon the actual magnitude and configuration of the applied loads. The bases of the wall footing excavations should extend a minimum of 18 inches below lowest adjacent grade. The footing excavations should then be lined with a minimum 6- inch -thick layer of compacted, imported, granular material, as described in the "Structural Fill" section of this report. The wall footings should be designed in accordance with the guidelines provided in the appropriate portion of the "Shallow Foundations" section of this report. 4.10.3 Wall Drainage and Backfill 1 The above design parameters have been provided assuming that back -of -wall drains will be installed to prevent build -up of hydrostatic pressures behind all walls. 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 well - graded sand or gravel, with not more than 5 percent by weight passing the U.S. Standard No. 200 Sieve and meeting ODOT SS 00510.12 - Granular Wall Backfill. We recommend the select granular wall backfill be separated from general fill, native soil, and /or topsoil using a geotextile fabric that meets the requirements provided in ODOT SS 350 and 2320 for drainage geotextiles. Alternatively, the on -site soils can be used as backfill material provided a minimum 2- foot -wide column of angular drain rock wrapped in a geotextile is placed against the wall and the on -site soils can be adequately moisture conditioned for compaction. The rock column should extend GEODESIGN= 14 PNWP -30- 02:071905 1 • 1� from the perforated drainpipe or foundation drains to within approximately 1 foot of the ground surface. The angular drain rock should meet the requirements provided in the "Structural Fill" section of this report. The wall backfill should be compacted to a minimum of 95 percent of the maximum dry density, as determined by ASTM D 1557. However, backfill located within a horizontal distance of 3 feet from a retaining wall should only be compacted to approximately 90 percent of the maximum dry 1 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 jumping jack or vibratory plate compactors). If flat work (sidewalks or pavements) will be placed 1 atop the wall backfill, we recommend that the upper 2 feet of material be compacted to 95 percent of the maximum dry density, as determined by ASTM D 1557. 1 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. The drain rock should meet specifications provided in the "Structural Fill" section of this report. The drain rock should be wrapped in a geotextile fabric that meets the specifications provided in ODOT SS 350 and 2320 for drainage geotextiles. 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. i Settlements of up to 1 percent of the wall height commonly occur immediately adjacent to the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend that construction of flat work adjacent to retaining walls be postponed at least 4 weeks after backfilling of the wall, unless survey data indicates that settlement is complete prior to that time. 1 4.11 PAVEMENT Pavements should be installed on native subgrade or new engineered fills 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. We have assumed that the traffic will consist of passenger cars and Tight delivery trucks, with an occasional bulk - handling larger truck. Our pavement recommendations are based on the following assumptions: 1 • The pavement subgrade is prepared as recommended in the "Site Preparation" and "Structural Fill" sections of this report. • The top 12 inches of soil subgrade below the roadway alignment is compacted to at least 92 percent of its maximum density per ASTM D 1557. • The CBR value is at least 4. This value was used to estimate a resilient modulus of 4,500 psi 1 for the subgrade. • A resilient modulus of 20,000 psi was estimated for the base rock. • Initial and terminal serviceability index of 4.2 and 2.5, respectively. 1 G EO DESIGN? 1 5 PNWP -30- 02:071905 4 ' _ • Reliability and standard deviation of 85 percent and 0.4, respectively. • Structural coefficient of 0.42 and 0.10 for the asphalt and base rock, respectively. Assuming the traffic volumes described in Table 1 and a 20 -year design, we calculated the pavement sections provided below. Our pavement design recommendations are summarized in Table 1 for two different traffic scenarios. r Table 1. Pavement Design Recommendations 1 Traffic Levels Pavement Thicknesses' (inches) Cars per Day Trucks per Day AC Base Rock 200 0 2.5 6.0 200 15 3.0 9.0 1 1. All thicknesses are intended to be the minimum acceptable values. If any of the above assumptions are incorrect, our office should be contacted with the appropriate information so that the pavement designs can be revised. The AC should be Level 2, 12.5 -mm, dense HMAC according to ODOT SS 00745 and be compacted to 91 percent of Rice Density of the mix as determined in accordance with ASTM D 2041. Minimum lift thickness for 12.5 -mm HMAC is 1.5 inches. Asphalt binder should be performance graded and conform to PG 70 -16. The base rock should meet the specifications for aggregate base rock provided in the "Structural Fill" section of this report. Construction traffic should be limited to non - building, unpaved portions of the site or haul roads. Construction traffic should not be allowed on new pavements. If construction traffic is to be allowed on newly constructed road sections, an allowance for this additional traffic will need to be made in the design pavement section. 4.12 SEISMIC DESIGN CRITERIA 4.12.1 IBC Parameters Seismic design criteria in accordance with 2003 IBC and 2004 SOSSC are summarized in Table 2. 1 1 1 1 GEODESIGN? 16 PNWP -30- 02:071905 , Table 2. Seismic Design Criteria Short Period 1 Second 1 Maximum Credible Earthquake Spectral Acceleration 5 = 1.06 g S� = 0.37 g Site Class C Site Coefficient F = 1.00 F = 1.43 Adjusted Spectral Acceleration SM5 = 1.06 g S. = 0.53 g 1 Design Spectral Response. Acceleration Parameters 0.70 g 0.35 g Design Spectral Peak Ground Acceleration 0.29 g 4.122 Liquefaction and Lateral Spreading Liquefaction can be defined as the sudden loss of shear strength in a soil due to an excessive buildup of pore water pressure. Liquefied soil layers generally follow a path of least resistance to dissipate pore pressures, often resulting in sudden surface settlement, sand boils or ejections, and /or lateral spreading in extreme cases. Clean, loose, uniform or silty, fine- grained, saturated sands are particularly susceptible to liquefaction. Lateral spreading is a liquefaction - related seismic hazard. Areas subject to lateral spreading are typically gently sloping or flat sites underlain by liquefiable sediments adjacent to an open face, such as riverbanks. Liquefied soils adjacent to open faces may "flow" in that direction, resulting in lateral displacement and surface cracking. Based on the soil plasticity and stiffness and groundwater elevation, it is our opinion that the on- site soils are not susceptible to liquefaction during the design seismic event. Consequently, there is no risk of lateral spreading. 5.0 OBSERVATION OF CONSTRUCTION Satisfactory foundation and earthwork performance depends to a large degree on quality of construction. Sufficient monitoring of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. 1 Subsurface conditions observed during construction should be compared with those encountered during the subsurface exploration. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect whether 1 subsurface conditions change significantly from those anticipated. We recommend that GeoDesign be retained to monitor construction at the site to confirm that 1 subsurface conditions are consistent with the site explorations and to confirm that the intent of project plans and specifications relating to earthwork and foundation construction are being met. 1 1 GEODESIGN? 17 PNWP-30- 02:071905 . 1111 6.0 LIMITATIONS We have prepared this report for use by Pacific Northwest Properties and the design and construction teams for the proposed Tigard Triangle Commons development. The data and report can be used for bidding or estimating purposes, but our report, conclusions, and 1 interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Explorations indicate soil conditions only at specific locations and only to the depths penetrated. They 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 preliminary at the time this report was prepared. When the design has been finalized and if there are changes in the preceding site grading or location, configuration, design loads, or type of construction for the building, 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. 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, expressed or implied, should be understood. oo♦ 1 We appreciate the opportunity to be of service to you. Please call if you have questions concerning this report or if we can provide additional services. Sincerely, GeoDesign, Inc. D PROF C It kii 630 I '! Scott P. McDevitt, P.E. 1 Geotechn .1 Project Engineer OREGON 11. • ,r OTT P F x M L eo k i' • nders, P.E. EXPIRES: t z( i o C Prince ► • Geotechnical Engineer 1 (` GEODESIGN? 18 PNWP -30- 02:071905 • 1111 . ' ,.k,� !�.: y am". EM� ,(.,�""`,,@ f„...7.,„,,, J' pr,(- �> b �'* � r � i �~ " �,-"' _, MI �. ! R Y Y rx'.. , ., . i ,1 1 ,, ^.' l.. fib v*' !! +— 7# ' 11 - , ..;........ a4 , t ,.._ , , f � I ' �. L ` ..r..1. ' ......• .2:- 't ,,,,,." -.. .. - 4! 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"� k y p t, z I ,e , " '*■,.' ...-/ ''.A',. al ,,,, . •‘: e 1 . 41 : 1- : t r 1 -,......., ,,. ., . ;„, ...„ 0 . , I Y � I� � �' ? L ! I !)' t. ti 4 - . ,,, ,, , , ,e el , , i „sriiiiiiiiti 1 "• .. , .. - USGS QUADRANGLE MAP y ' • •. , 1 ,�� I 2000 4000 I00 z MAP CR EATED WITH TOPO! ® : 7 - „... - 3 � ©2002 NATIONAL GEOGRAPHIC �� " � (IN FEET) 0 • l't ILIKIEL. ., G ED DES IGN W. PNWP -30 -02 VICINITY MAP N 15575 SW Sequoia Parkway - Stine 100 I N Portland OR 97224 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE 1 Off 503.968.8787 Fax 503.968.3068 TIGARD, OR N W cc c r _ -- ' .. U \ c LL - \ c . ` . - - - r 00J5Y S 5 W \ \ 1 i �' I • • \r r fY w /..5 , , , ` � � I w o L; S z3 1 i i a • �r LA :8 i /gal' , , 3.0 01 ° _ _ _ "•-_-_,_:_„ , LLI 1 CURB uNe J _ iii �� '' ` / / li P � . s _ � l ��' I - - J :00' •41 ��2�I� / ( . ' 1 . 2 / ■e >17 5 — - — ' T g � , ' ii J ��.1�� i ATP 5 + I P s z _ z �" - -- y — +� R `0P0SEQ BUELDIIVG >f__ — �; ° - - . iII. 1 FF 325. - -- - -- � � � 0 _ e - -- '1110111g :I.\ , i` y ` ® - _ X32 >4.5 � �'�g N. 1 , Ee l ; P -- � / / _i o � � / __ , k . (' r� o i ce ° / G /" , %�!/ �� ea.as; � � 7 - ,-- .,'' 4, _ ENNEERramori.I.--riAMMEMIMENIEMENOMMINMEMMimill,4111101ENIENENEP. '~8 w ' iNI 1 i � / �� Ie� Z • \ - 320 3 �e / _ 1 _ _N _ _ _ _ __. ... . S,• . SW 67 \ th AVE. NEW> . , j l i z FO t.::., 1 EXPLANATION: 1 �, ` 13.0 TEST PIT /DEPTH TO REFUSAL, FT - COMPLETED BY GEODESIGN, INC. USING _ _ _ f 0 50 100 FT TP 1 A 30 -TON CAT 225 (AUGUST 2001) WA . 5.0 ,, I ' ® TEST PIT /DEPTH TO REFUSAL, FT - I COMPLETED BY GEOPACIFIC SITE PLAN FROM DRAWING PROVIDED BY ENGINEERING, INC. USING A 8 -TON ANKROM MOSIAN ASSOCIATED ARCHITECTS MITSUBISHI MS070 (MARCH 2001) 1 MEASUREMENT ROD, 1/2" DIAMETER PIPE OR REBAR CASING, 2" DIAMETER PIPE (SET ON PLATE, NOT FASTENED) COUPLING WELDED TO PLATE SETTLEMENT PLATE 16 "x16 "x1/4" • SAND OR GRAVEL PAD IF NECESSARY EXISTING GROUND SURFACE NOT TO SCALE 1 NOTES: 1. INSTALL MARKERS ON FIRM GROUND OR ON SAND OR GRAVEL PADS IF NEEDED FOR STABILITY. TAKE INITIAL READING ON TOP OF ROD AND AT ADJACENT GROUND LEVEL PRIOR TO PLACING ANY FILL. b 2. FOR EASE IN HANDLING, ROD AND CASING ARE USUALLY INSTALLED IN 5 -FOOT SECTIONS. AS FILL PROGRESSES, COUPLINGS ARE USED TO INSTALL ADDITIONAL LENGTHS. CONTINUITY I5 MAINTAINED BY READING THE TOP OF THE MEASUREMENT ROD, THEN IMMEDIATELY ADDING THE NEW SECTION AND READING THE TOP OF THE ADDED ROD. BOTH READINGS ARE RECORDED. 3. RECORD THE ELEVATION OF THE TOP OF THE MEASUREMENT ROD IN EACH MARKER AT THE RECOMMENDED TIME INTERVALS. EACH TIME, NOTE THE ELEVATION OF THE ADJACENT FILL SURFACE. V I 4 m . READ THE MARKER TO THE NEAREST 0.01 FOOT, OR 0.005 FOOT IF POSSIBLE. NOTE THE FILL ELEVATION TO THE NEAREST 0.1 FOOT. 5. THE ELEVATIONS SHOULD BE REFERENCED TO A TEMPORARY BENCHMARK LOCATED ON STABLE ' GROUND AT LEAST 500 FEET FROM THE EMBANKMENT. 0 D 1 N 1 • G EODESIGN? PNWP -30-02 SETTLEMENT PLATE DETAIL 15575 SW Sequoia Parkway Suite 100 o: Portland OR 97224 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE Off 503.968.8787 Fax 503.968.3068 TIGARD, OR APPENDIX A 1 FIELD EXPLORATIONS ' GENERAL Subsurface conditions at the site were explored by excavating 11 test pits (TP -1 through TP -11) to depths of 7.5 to 16.0 feet BGS. The test pits were excavated on June 16, 2005 by Western States Soil Conservation, Inc. of Aurora, Oregon, using a Hitachi EX -120 trackhoe. The approximate locations of the explorations are shown on Figure 2. Logs of the explorations are included in this appendix. Logs of previous explorations are presented in Appendices B and C. 1 The locations of the explorations were determined in the field by pacing from site features. This information should be considered accurate to the degree implied by the methods used. SOIL SAMPLING A member of our geologic staff observed the explorations. We obtained representative samples of the various soils encountered in the test pits for geotechnical laboratory testing. Samples were obtained from the trackhoe bucket and sealed in plastic bags. Soil classifications and sampling intervals are shown on the exploration logs included in this appendix. A relatively undisturbed sample was obtained using a standard Shelby tube in general accordance with guidelines 1 presented in ASTM D 1587, the Standard Practice for Thin - walled Tube Sampling of Soils. SOIL CLASSIFICATION The soil samples were classified in accordance with the "Key to Test Pit and Boring Logs Symbols" (Table A -1), `Soil Classification System and Guidelines" (Table A -2), and "Rock Classification System and Guidelines" (Table A -3), copies of which are included in this appendix. The exploration logs indicate the depths at which the soil /rock or their characteristics change, although the change actually could be gradual. Classifications and sampling intervals are shown on the exploration logs included in this appendix. LABORATORY TESTING 1 CLASSIFICATION The soil samples were classified in the laboratory to confirm field classifications. The laboratory classifications are included on the exploration Togs if those classifications differed from the field classifications. MOISTURE CONTENT DETERMINATION We tested 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 soil in a test sample and is expressed as a percentage. The test results are included on the exploration logs presented in this appendix. FINES CONTENT ANALYSIS Fines content analyses were completed on one sample in general accordance with ASTM C 117 (percent passing a U.S. Standard No. 200 Sieve). The test results are presented on the exploration logs in this appendix. G EODESIGN- A -1 PNWP -30- 02:071905 .1 CONSOLIDATION TESTING We performed a one - dimensional consolidation test in general accordance with ASTM D 2435 on a relatively undisturbed sample obtained from the test pit explorations. The test measures the volume change of a soil sample under predetermined Toads. The results of the consolidation tests are included in this appendix. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 GEODESIGN_ A -2 PNWP -30- 02:071905 1 I I •. • KEY TO TEST PIT AND BORING LOG SYMBOLS SYMBOL SOIL DESCRIPTION 1 IE Location of sample obtained in general accordance with ASTM D 1586 Standard Penetration Test with recovery 1 Location of sample obtained using thin wall, shelby tube, or Geoprobe® sampler in general 1 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 sampler and 140 -pound hammer or pushed P 9 P P with recovery I Graphic Log of Soil and Rock Types Location of grab sample : :.,,•a Observed contact '- .', between soil or rock units I. '' (at depth indicated) Rock coring interval Inferred contact between soil or rock units Water level during drilling (at approximate depths i; . - indicated) 1 1 Water level taken on date shown GEOTECHNICAL TESTING EXPLANATIONS I PP Pocket Penetrometer DD Dry Density I TOR Torvane ATT Atterberg Limits CON Consolidation CBR California Bearing Ratio DS Direct Shear OC Organic Content P200 Percent Passing U.S. Standard No. 200 P Pushed Sample Sieve I RES Resilient Modulus HYD Hydrometer Gradation VS Vane Shear UC Unconfined Compressive Strength kPa kiloPascal SIEV Sieve Gradation 0 ENVIRONMENTAL TESTING EXPLANATIONS i . 8 b CA Sample Submitted for,Chemical Analysis ND Not Detected r ! I PID Photoionization Detector Headspace Analysis NS No Visible Sheen T g ppm Parts Per Million SS Slight Sheen MS Moderate Sheen P Pushed Sample ro HS Heavy Sheen J Il 1; Y G EO DESIG N? KEY TO TEST PIT AND BORING LOG SYMBOLS TABLE A -1 1 15575 SW Sequoia Parkway - Suite 100 E LL Portland OR 97224 I Z y OR 503.968.8787 Fax 503.968.3068 • SOIL CLASSIFICATION SYSTEM ` CONSISTENCY - COARSE - GRAINED SOILS II • 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 - 1 0 1 1 - 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 SOIL CLASSIFICATION NAME Name and Modifier Terms Constituent Percentage GRAVEL, SAND >50% I sandy, gravelly 30 - 50% silty, clayey 15 - 50% Coarse - grained some (gravel, sand) 15 - 30% some (silt, clay) 5 15% 1 trace (gravel, sand) trace (silt, clay) <5% CLAY, SILT >50% silty, clayey sandy, gravelly 30 50% Fine - grained some (sand, gravel) 15 30% some (silt, clay) 1 trace (sand, gravel) 5 - 15% trace (silt, clay) PEAT 50 - 100% Organic organic (soil name) 15 - 50% (soil name) with some organics 5 - 15% MOISTURE CLASSIFICATION Term Field Test I dry very low moisture, dry to touch moist damp, without visible moisture I o wet visible free water, usually saturated GRAIN SIZE CLASSIFICATION 8 Description Sieve* Observed Size boulders - >12" 0 d cobbles - 3" - 12" gravel coarse 0.75" - 3" 0.75" - 3" ;, fine #4 - 0.75" 0.19" - 0.75" I coarse #10 - #4 0.079" - 0.19" sand medium #40 - #10 0.017" - 0.079" fine #200 #40 00029" 0.017" i III fines < #200 <0.0029" * Use of #200 field sieve encouraged A ' GEODESIGN? 1 V 1 55755WSequoiaPa , kway • 5uite100 SOIL CLASSIFICATION SYSTEM AND GUIDELINES TABLE A -2 E Z Portland OR 97224 a OR 503.968.8787 Fax 503.968.3068 LL 1 o u w Z J DEPTH a MATERIAL DESCRIPTION 1110- I- g MOISTURE COMMENTS H Ln u O 50 100 —o o Soft to medium stiff, dark gray SILT with - :: trace to some organics (roots up to 1 L inch diameter); moist (topsoil, 3- to 4- -1 -, inch -thick root zone). - Medium stiff to stiff, gray SILT with 1.3 ® PP = 1.5 tsf I - orange mottles, trace fine sand, and PP pp PP = 2.5 tsf occasional organics (fine rootlets); 2.5 — moist. — - grades to Tight brown, gray- orange with ' occasional fine, subrounded gravel at 5 — 4.0 feet P200 • PP = 3.0 tsf PP • P200 = 70% - - - grades to clayey with occasional 1 2.5 — boulders to 2 -foot diameter at 7.0 feet 1 Slow groundwater seepage observed at 9.5 feet. 10.0— • Minor caving observed at 10.5 Dense, gray red - brown, clayey 10.5 feet. G B OULDERS; moist to wet. Hard digging at 11.0 feet. d I ,O 12.5— r a J o -° Dense, red - brown, clayey GRAVEL with 13.5 some sand and cobbles, and occasional id _p boulders; boulders; moist to wet (residual basalt). ri I D QCs' 1- • 1 5.0 __ b a. c ,o> I/ r pq:c In Test pit completed at 16.0 feet. 16.0 w w 0 0 I 1 7.5— 9 0. I F - N O O • d z 20.0 - a 0 50 100 I w o. EXCAVATED BY Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 cc a EXCAVATION METHOD: trackhoe (see report text) I G EO DEC I G N z PNWP 30 02 TEST PIT TP -1 E. ✓ N 1 557559/ Sequoia Parkway • Suite 100 TIGARD TRIANGLE COMMONS IL Portland OR 97224 JULY 2005 FIGURE A -1 1 I- OH 503.968.8787 F. 503.968.3068 TIGARD, OR V 1 O = U _, - DEPTH u >11-- Z a • MOISTURE COMMENTS 1 FEET .za MATERIAL DESCRIPTION _1 N 2 CONTENT% p w t Q -o o u }-- o S0 100 . .. Soft, brown -gray SILT with some gravel Likely side - by - side with .•; and organics (3- inch - diameter wood 10 foot - deep previous test pit. 1 ❖ fragments and roots), and occasional ...._ ii debris (asphalt fragment) and boulders; .•.. moist (fill, 4- inch -thick root zone). :• 1 .❖ .❖ 2.5 . * ** ,,. O.. .•«• .❖ 1 1 5.0 ❖. 11 1 .❖ cc 1 0 1 VP, Slow groundwater seepage :•: 10.0 observed at 10.0 feet. Medium stiff, red - brown CLAY with some 10 Moderate to severe caving boulders; moist. ® observed at 10.0 feet. 1 Z 1 Test pit completed at 12.0 feet due to 120 • 12.5 — refusal. 0 a 1 - e - w r - 0 z 15.0 — c 1 a - 1— 1 Z — W — O 0 17.5— ❑ 1 E 1- _ o 1 6 z 20.0 a 0 S0 100 w 1 a EXCAVATED BY: Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06 /16/05 cc w a EXCAVATION METHOD: trackhoe (see report text) O G EO DES I G NZ PNWP 30 02 TEST PIT TP 2 1 ,,-,- _ r/J i S S7 S SW Sequoia Parkway - Sure 100 W Portland OR 97224 JULY 2005 TIGARD TRIANGLE COMMONS I— ON 503 - 968.8787 Fax 503.968.3068 TIGARD, OR FIGURE A -2 1 • - . u o u w I DEPTH Z J ET a MATERIAL DESCRIPTION w W N g CONTENT MOISTURE COMMENTS % ° I- < 0 0 50 100 I —o.o a Medium dense, brown -gray, silty GRAVEL ;•;: with trace to some sand; moist, well : graded, subrounded (fill, 1- inch -thick :; root zone). V. ;.;•' Medium stiff, dark brown, brown -gray 2.0 L , 2.5 ❖ : SILT with trace fine sand and occasional PP = 1.25 tsf *'.' organics (fine rootlets); moist (fill). _ PP ® • Stiff, light brown -gray SILT with orange 3.0 mottles and trace fine sand and clay; moist, low plasticity. P200 PP = 2.5 tsf PP ® • P200=91% 1 5 — 1 ' 7.5 — ® • with some basalt boulders to silty Minor caving observed at 8.5 feet. 1 - boulders to 2%z -foot diameter at 8.5 feet 10.0— , No groundwater seepage observed Test pit completed at 11.0 feet due to 11 to the depth explored. refusal on boulders. 12.5 — I o 0 w I Z . • 15.0 — E a i 1- z 0 9 z O - rn w 0 I 0 1 7.5 — 0 Y. ~ - N O 0 • d z 20.0 0 50 100 EL I w CD EXCAVATED BY: Westem States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 tc 0. EXCAVATION METHOD: trackhoe (see report text) I ▪ G EODESIGN Z PNWP -30 -02 TEST PITTP -3 a — 5)i 155755w5equoiaParkway Suite 100 TIGARD TRIANGLE COMMONS w Portland OR 97224 JULY 2005 FIGURE A-3 1 ~ Of, 503.968.8787 Fax 503.968.3068 TIGARD, OR u u W o . DEPTH Z ii •M OIS TURE • II FEET d MATERIAL DESCRIPTION w w E m CONTENT % COMMENTS p uJ < ~ vl 0 50 100 ;:;4 Soft to medium stiff, brown, gravelly • V., SILT with trace organics (roots up to %2- 1 `.k,et inch diameter); moist (fill, 3- inch -thick 0 7 � it ik root zone). • • Medium stiff, dark brown- orange SILT 1.5 PP = 1.0 tsf with trace fine sand and organics (roots PP ® • 1 up to %2 -inch diameter); moist, low 2.5 — . lasticity (topsoil). Stiff to very stiff, light brown -gray SILT with orange mottles, trace fine sand and PP PP = 2.75 tsf - clay, and occasional organics (fine 1 - rootlets); moist. with isolated 3- inch - diameter tree root at 4.0 feet 1 s.o— grades with some boulders at 5.0 feet --'0....'... o Dense, red - brown, clayey GRAVEL with 6.0 1 some boulders and cobbles; moist ° � ® • o ff+ , (residual basalt). o . No groundwater seepage observed 7.5 Y;.. to the depth explored. Test pit completed at 7.5 feet due to 7.5 No caving observed to the depth - refusal on basalt. explored. 1 10.0— 1 1 2.5 — 1 o _ 1 F. iL a z 1 5.0— is 1 a . 1 - - 0 1 0 Z - 0 rn w - 0 0 0 1 7.5 — • 1 'a P E o N 0 o d 1 2 20.0 a 0 50 100 w 1 a EXCAVATED BY: Westem States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 ct a EXCAVATION METHOD: trackhoe (see report text) ° u PNWP-30-02 TEST PIT TP -4 1 G EO ESIGN? 1— rn 1 5575 SW Sequoia Parkway - Suite 100 Ill Portland OR 9722 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE A -4 OH 503.968.8787 Fax 503.968.3068 TIGARD, OR 1 U . t = V J ' z DEPTH H a MATERIAL DESCRIPTION wlW N • MOIISTuR/E COMMENTS H • < l7 0 50 100 —0 Medium stiff to stiff, Tight brown -gray - SILT with orange mottles, trace fine sand, and occasional organics (fine ® PP = 1.5 tsf Y2 rootlets and roots up to -inch PP • - diameter); moist (2%2- inch -thick root I _ zone). 2.5 — - grades to very stiff and orange -brown at PP PP = 3.0 tsf - 3.0 feet PP = 3.0 tsf PP ® • 5.0 — I 7.5 — Slow to moderate groundwater Dense, red, gray brown BOULDERS (to 3- 6.5 ® seepage observed at 8.5 feet. c foot diameter) with some clay, gravel, _. -' and sand; moist to wet (residual basalt). 10.0 O Minor caving observed from 10.0 . to 12.5 feet. J • ,G � O 1 2.5 ( ® • Test pit completed at 12.5 feet due to 12.5 refusal on basalt. I 0 A W • I 6 Z 15.0 — a 111 1- O 5 Z o 0 w 0 o w 17.5— 0 a. 0 E I F 04 0 0 a z 20.0 0 50 100 a I w a EXCAVATED BY: Westem States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 w a EXCAVATION METHOD: trackhoe (see report text) I 0 G E DES I G Nz PNWP -30 -02 TEST PIT TP -5 — In 15575 SW Sequoia Parkway • Suite 100 TIGARD TRIANGLE COMMONS W Portland OR 97224 JULY 2005 FIGURE A -5 I 1- Off 503.968.8787 f 503.968.3068 TIGARD, OR 1 L w - DEPTH > I �=- Z a • MOISTURE FEET a MATERIAL DESCRIPTION W w I- m CONTENT % CO ° I V 0 50 100 --0. ilt3 Medium stiff, dark brown -gray SILT with , "..' trace fine sand and organics (roots up to 1 1 -inch diameter); moist (topsoil, 2- to 3- 0.7 inch -thick root zone). - Medium stiff to stiff, gray SILT with PP PP = 1.5 tsf orange mottles, trace fine sand and clay, 1 and occasional organics (roots up to Y- 1 2.5 — inch diameter); moist. ® PP = 2.5 tsf I r grades to light brown at 3.0 PP • j t - feet 1 J y - 5.0 — 1 1 - grades to some boulders to silty 7.5 — boulders at 7.0 feet 1 • Stiff, red -brown CLAY with some silt and 9 . 0 ® I / trace gravel; moist, medium to high to.o plasticity (residual basalt). Slow groundwater seepage grades to no gravel and high plasticity observed at 10.0 feet. at 10.0 feet 1 grades to some sand and gravel at 12.0 1 l z.s feet 0 iii o ® No caving observed to the depth 1 Test pit completed at 14.0 feet. 14 explored. w _ o z 15.0 — 1 EE a - 0 O 1 z - w 0 0 17.5— 1 El t? Y. F N 1 O a z 20.0 - a 0 50 100 w 1 a EXCAVATED BY: Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 0 w a EXCAVATION METHOD: trackhoe (see report text) 6 ° u PNWP -30 -02 TEST PIT TP -6 GEO ESIGN? H w 153755WSequoiaParkway-Suite100 ) 2005 TIGARD TRIANGLE COMMONS FIGURE A -6 Portland O 503 TIGARD, OR , OH 503.9P88.68788Fax Pax x 503.968.3068 N . - a u w DEPTH U > H z a • MOISTURE FEET a MATERIAL DESCRIPTION wIW N g CONTENT % COMMENTS IA ° w V 0 50 100 —fl. o •;: Medium stiff, brown -gray- orange SILT V. with trace to some organics (roots up to . : •; Yz -in diameter); moist (fill, 3- inch -thick t'= root zone). r 1 ; ,, t Medium stiff to stiff, dark gray SILT with I ;; t, trace fine sand and organics (roots up to PP = 1.5 tsf . LS LS 1 -inch diameter); moist (possible old pp ® • 2.5 ue \topsoil). ` 2.5 Stiff, gray SILT with orange mottles, PP PP = 1.75 tsf trace clay and fine sand, and occasional organics (roots up to % -inch diameter); moist. pp ® PP = 1.75 tsf grades to Tight brown - orange -gray with occasional organics (fine rootlets) at 4.0 s . o — feet - with some boulders at 7.0 feet ® • u • 7.5 — I - 10.0— 1 Stiff, gray- brown -red, gravelly CLAY with 1 . 0 some boulders (18 -inch diameter) and I cobbles of basalt; moist (residual basalt). 12.5 a Slow groundwater seepage observed at 14.0 feet. iL I p- o • 15.0 / No caving observed to the depth z Test pit completed at 1 5.0 feet. ' 5. 0 explored. E a I ~ - 0 r? Z C- 05 W - 0 I 0 111 1 (.'9 a 1 N O M d Z 20.0 0 50 100 O. I w a EXCAVATED BY: Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 ce O. EXCAVATION METHOD: trackhoe (see report text) III 6 0 • G EO DES G N? PNWP 30 02 TEST PIT TP -7 N 15575 SW Sequoia Parkway • Suite 100 TIGARD TRIANGLE COMMONS lL Portland JULY 2005 3- TIGARD, OR FIGURE A -7 Off 503.968.8787 fax 503.968.3068 L) g L LL, - DEPTH v 91E: Z —1 • MOISTURE FEET d MATERIAL DESCRIPTION N g CONTENT % COMMENTS p w < ~ `n o 50 100 —0 ° a ""' M edium stiff, dark gray SILT with some .," 1 -t",„'" organics (roots up to 3 -inch diameter) i "" and trace sand and clay; moist (topsoil, gi L.; 2- to 3- inch -thick root zone). �' pp PP = 1.25 tsf grades to gray -dark gray with orange • 1 2.5 mottles and occasional organics (roots / 2.5 PP ® P P = 1.0 tsf _ \ _p to 1 4 -inch diameter) at 2.0 feet J ,,,.. Medium stiff light brown-gray-orange 1 - SILT with trace fine sand and clay; moist. ® PP = 1.0 tsf PP 5.0 — 1 1 7.5— 1 with isolated boulders up to 2 -foot diameter at 8.0 feet I 10.0 ,J Medium stiff, red -brown CLAY with 10.0 0 • j occasional boulders, cobbles, and gravel; moist to wet, high plasticity 1 (residual basalt). 12.5 _ / ® 1 boulder zone at 12.5 feet /// No groundwater seepage observed 1 /i to the depth explored. Test pit completed at 1 4.0 feet due to 14. No caving observed to the depth 1- - refusal on basalt /boulders. explored. 0 z 15.0 — ¢ 1 o- o 1 0 0 rn w - 0 0 1 7.5 — 1 c? Y. g N O - d 1 z 20.0 0. 0 50 100 w 1 a EXCAVATED BY: Westem States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 cc w o- EXCAVATION METHOD: trackhoe (see report text) O t- G EODESIGNZ PNWP -30 -02 TEST PIT TP -8 I 1- — r co 15575 SW Sequoia Parkway • Suite 100 W PoRIandOR97224 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE A -8 Off 503.968.8787 F. 503.968.3068 TIGARD, OR 1 I . K DEPTH a MATERIAL DESCRIPTION WIW H 2 •ONTENTR%E COMMENTS 0 50 100 —0.0 ik Medium stiff, dark brown SILT with trace , P S sand and organics (roots up to Y2 inch On east side of test pit, coarse ' " diameter); moist (topsoil, 3-inch-thick 2 - inch aggregate drain line inn goof zone). r 1 running north -south from 1.0 to Medium stiff to stiff, gray SILT with PP 2.0 feet. 1 - orange mottles, trace fine sand and clay, PP = 1.0 tsf and occasional organics (fine rootlets); PP PP = 1.75 tsf 2.5 — moist to wet. • I I w groundwater S o seepage observed at 4.0 feet. I 5 - grades to moist at 5.5 feet - I 7.5 — ® • Slow groundwater seepage observed at 8.0 feet. - boulder zone (with silt) to 3 - foot Minor caving observed at 8.5 feet. I = diameter at 8.5 feet 10.0 J/ Stiff, gray- red -brown CLAY with some 10.0 ' silt, gravel, and sand, and trace cobbles and boulders; moist to wet (residual basalt). I N • 12.s / o Soft to medium hard (R2 -R3), gray CO o BASALT; slightly to moderately [ 13.5 ,weathered. - 13.0 Test pit completed at 1 3.5 feet due to a - refusal on basalt. I o 1 5.0 — a • • 0 2 - U w w - 0 0 t w 7 17.5— E.' c� a I 0 N O O d z 20.0 0 50 100 a. I to a. EXCAVATED BY: Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16105 a a EXCAVATION METHOD: trackhoe (see report text) I o G EO DEC I G Nz PNWP -30 -02 TEST PIT TP -9 ✓ — rn 15575 SW Sequoia Parkway Starr 100 TIGARD TRIANGLE COMMONS w 3 JULY 2005 FIGURE A -9 I F " Off 503,968.8787 68.8787 Fax 1,0 50 503.988.3068 TIGARD, OR 1 u o m u w Z DEPTH •1 EE H MATERIAL DESCRIPTION 9F- N 2 • ONTENT R % COMMENTS ° w N L.1 0 50 100 —0 .: Soft to medium stiff, dark brown SILT "" "' with trace fine sand and organics (roots 1 _ up to % -inch diameter); moist (topsoil, 4- D , B inch -thick root zone). - Medium stiff to stiff, Tight brown -brown ® PP = 1.0 tsf SILT with orange mottles, trace fine sand PP 1 and occasional organics (roots up to /z- . 2.5 — inch diameter); moist. grades to stiff and gray with orange PP ® • PP = 1.5 tsf i - mottles at 3.0 feet 5.0 — grades to stiff to very stiff with some PP ® PP = 2.5 tsf 1 - clay and no organics; medium plasticity _ at 5.0 feet 1 grades to light brown -gray- orange with trace clay; low plasticity at 6.0 feet 7.5 — ® • Slow groundwater seepage 1 - observed at 9.0 feet. 10.0— Slow groundwater seepage 1 - with occasional cobbles and boulders at observed at 11.0 feet. 11.0 feet 1 5 No caving observed to the depth 1 Test pit completed at 12.5 feet. 12.5 explored. o 1 N N _ n w _ 0 _ • 1 5.0 — z 2 a - 0 r? 1 0 y W O O 1 7.5 — 1 a - E. 1 N O ,7 - a z 20.0 - a 0 SO 100 a W 1 EXCAVATED BY: Western States Sod Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 ct a EXCAVATION METHOD: trackhoe (see report text) t7 • G EO DESI G N Z PNWP 30 02 TEST PIT TP -10 1 m 15575 SW Sequoia Parkway. site 100 TIGARD TRIANGLE COMMONS W 8 R 9 5 5 787 9701 J ULY 2005 TIGARD, OR FIGURE A -10 1 F O% 503.968.8787 F. 503.968.3068 DEPTH = z MATERIAL DESCRIPTION w - g • MOISTURE ONT COMMENTS FEET wl w N u 0 50 100 —0 " *• *•* Soft to medium stiff, dark gray -gray- I .... orange SILT with trace fine sand and •;•; occasional organics (roots up to % -inch :; :: diameter); moist (fill, 4- inch -thick root .• zone). PP PP = 1.0 tsf I , ` t Medium stiff to stiff, dark gray SILT with 1.8 r' some clay and trace organics (roots up 2.5 ° o'c tito 3 / -inch diameter); moist (topsoil). , z 7 PP ® PP = 1.5 tsf - - Stiff to very stiff, Tight brown SILT with I orange mottles, trace fine sand, and occasional organics (fine roots up to PP = 2.5 tsf t : - 1 /8 - inch diameter); moist, low plasticity. PP ® • 5 - - 1 7.5 — • 1 - with isolated basalt boulders up to 2- 10.0 foot diameter at 9.5 feet 1 Stiff, j gray -dark gray CLAY with some silt; 10.5 - / moist, medium to high plasticity (residual basalt). PP = 1.5 tsf 1 PP El 12.5 o I o 0 F. o Z 15.0 grades to some gravel and cobbles; N . E2 moist to wet at 1 5.0 feet No groundwater seepage observed to the depth explored. ' o Test pit completed at 1 6.0 feet. 16.0 No caving observed to the depth explored. 0 0 w - 0 w 17.5 — 0 O rV O o 0. z 20.0 0 50 100 I w a ID<CAVATED BY: Western States Soil Conservation, Inc. LOGGED BY: JGH COMPLETED: 06/16/05 Ir 0. EXCAVATION METHOD: trackhoe (see report text) I e G EO DES I G Nz PNWP -30 -02 TEST PIT TP -1 1 0. — 5 15575 SW Sequoia Partway • Suite 100 TIGARD TRIANGLE COMMONS I W Portland OR 97224 JULY 2005 FIGURE Al - 1 I"' Off 503.968.8787 Fax 503.968.3068 TIGARD, OR • -0.010 - 1 0.015 -- — — 1 9`Y 0.040 z u z w 0.065 — —- — z ce 1 0.090 — I 0.115 -- -- Y 1 0.140 100 1000 10000 100000 PRESSURE (PSF) u EXPLORATION SAMPLE MOISTURE DRY KEY NUMBER DEPTH CONTENT DENSITY SOIL DESCRIPTION 0 (FEET) (PERCENT) (PCF) Light brown, gray- orange SILT with fine —.- TP -1 4.5 26.6 93.2 gravel .7 0 0 0 0 G EO PNWP -30 -02 CONSOLIDATION TEST RESULTS n 15575 SW Sequoia Parkway • Suite 100 Portland OR 97224 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE A -12 Off 503.968.8787 Fax 503.968.3068 TIGARD, OR 1 • APPENDIX B 1 PREVIOUS FIELD EXPLORATIONS BY GEODESIGN, INC. ' We explored subsurface conditions at the site in a previous investigation by excavating four test pits to depths of up to 17 feet BGS in the northern and eastern portions of the site. Test pits were excavated in September 2001 using methods similar to those described in Appendix A. A qualified member of our geotechnical staff observed and documented field activities. A copy of the site plan and exploration Togs from our report is included in this appendix. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 G EO DESIGN? 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LA --I Z CI 0 X 0 u z GEODESIGN_ PNWP-30-02 SITE PLAN 15575 SW Sequoia Parkway - Suite 100 Portland OR 97224 JULY 2005 TIGARD TRIANGLE COMMONS FIGURE 2 Off 503.968.8787 Fax 503.968.3068 TIGARD, OR i KEY TO TEST PIT AND BORING LOG SYMBOLS ' , SYMBOL SOIL DESCRIPTION I ILI Location of sample obtained in general accordance with ASTM D 1586 Standard Penetration Test I III Location of SPT sampling attempt with no sample recovery il Location of sample obtained using thin wall, shelby tube, or G o eo sampler in p g y e prob p general accordance with ASTM D 1587 Location of thin wall, shelby tube, or Geoprobe® sampling attempt with no sample recovery I 1 Location of sample obtained using Dames and Moore sampler and 300 pound hammer or pushed M Location of Dames and Moore sampling attempt (300 pound hammer or pushed) with no 1 sample recovery N Location of grab sample I Rock Coring Interval Water level GEOTECHNICAL TESTING EXPLANATIONS PP Pocket Penetrometer LL Liquid Limit TOR Torvane PI Plasticity Index 1 CONSOL Consolidation PCF Pounds Per Cubic Foot DS Direct Shear PSF Pounds Per Square Foot I P200 Percent Passing U.S. No. 200 Sieve TSF Tons Per Square Foot W Moisture Content P Pushed Sample 1 DD Dry Density OC Organic Content ENVIRONMENTAL TESTING EXPLANATIONS I CA Sample Submitted for Chemical Analysis ND Not Detected PID Photoionization Detector Headspace NS No Visible Sheen Analysis SS Slight Sheen I PPM Parts Per Million MS Moderate Sheen MG /KG Milligrams Per Kilogram HS Heavy Sheen I P Pushed Sample KEY TO TEST PIT AND 1 GEODESIGN BORING LOG SYMBOLS TABLE A -1 SOIL CLASSIFICATION SYSTEM - 1 MAJOR DIVISIONS SYMBOL NAME • 1 Gravel Well graded, fine to coarse More than 50% of Gravel GW gravel 1 Coarse Grained coarse fraction GP Poorly graded gravel Soils retained on GM Silty gravel No. 4 Sieve Gravel with Fines I GC Clayey gravel More than 50% Well graded, fine to coarse retained on No. 200 Sand Sand SW sand Sieve More than 50% of SP Poorly graded sand 1 coarse fraction passes No. 4 Sieve Sand with Fines SM Silty sand SC Clayey sand 1 Silt and Clay ML Low plasticity silt Inorganic Fine Grained Soils Liquid Limit CL Low plasticity clay Tess than 50% Organic OL Organic silt, organic clay 1 More than 50% passes Silt and Clay MH High plasticity silt No. 200 Sieve Liquid Limit Inorganic CH High plasticity clay, fat clay greater than 50% Organic OH Organic clay, organic silt I Highly Organic Soils PT Peat SOIL CLASSIFICATION GUIDELINES GRANULAR SOILS COHESIVE SOILS Standard Standard Unconfined 1 Relative Density Penetration Consistency Penetration Compressive Resistance Resistance Strength (tsf) Very Loose 0 - 4 Very Soft Less than 2 Less than 0.25 I Loose 4 -10 Soft _ 2 -4 _ 0.25 -0.50 Medium Dense 10 - 30 Medium Stiff 4 - 8 0.50 - 1.0 Dense 30 - 50 Stiff 8 - 15 1.0 - 2.0 I Very Dense More than 50 Very Stiff 15 - 30 2.0 - 4.0 Hard More than 30 More than 4.0 1 GRAIN SIZE CLASSIFICATION Boulders 12 - 36 inches Subclassifications 1 Cobbles 3 - 12 inches Percentage of other material in sample Gravel 3 /4 - 3 inches (coarse) Clean 0 - 2 ''A -% inches (fine) Trace 2 -10 1 Sand No. 10 - No. 4 Sieve (coarse) Some 10 - 30 No. 10 - No. 40 Sieve (medium) Sandy, Silty, Clayey, etc. 30 - 50 1 No. 40 - No. 200 Sieve (fine) Dry = very low moisture, dry to the touch; Moist = damp, without visible moisture; Wet = saturated, with visible free water. 1 SOIL CLASSIFICATION SYSTEM GEODESIGN AND GUIDELINES TABLE A -2 1 ROCK CLASSIFICATION GUIDELINES 1 HARDNESS DESCRIPTION Very soft (RH -0) For plastic material only 1 Soft (RH -1) Carved or gouged with a knife Moderate (RH -2) Scratched with a knife I Hard (RH -3) Difficult to scratch with a knife ry hard (RH 4) Rock scratches metal; rock cannot be scratched with a knife I STRENGTH DESCRIPTION Plastic Easily deformable with finger pressure 1 Friable Crumbles by rubbing with fingers Weak Crumbles only under light hammer blows Moderately Strong Few heavy hammer blows before breaking 1 Strong Withstands few heavy hammer blows and yields large fragments Very Strong Withstands many heavy hammer blows, yields dust and small fragments 1 WEATHERING DESCRIPTION Severely Weathered Rock decomposed; thorough discoloration; all fractures extensively coated with I Moderately Weathered clay, oxides, or carbonates Intense localized discoloration of rock; fracture surfaces coated with weathering minerals 1 Little Weathered Slight and intermittent discoloration of rock; few stains on fracture surfaces Fresh Rock unaffected by weathering 1 FRACTURING FRACTURE SPACING Crushed Less than 5/8 inch to contains clay 1 Highly Fractured 5/8 inch to 2 inches Closely Fractured . 2 inches to 6 inches I Moderately fractured 6 inches to 1 foot Little Fractured 1 foot to 4 feet • Massive Greater than 4 feet 1 JOINT SPACING DESCRIPTION 1 Papery Less than 1 /8 inch . ey or Platey 1/8 inch to 5/8 inch Very Close 5/8 inch to 3 inches 1 Close 3 inches to 2 feet Blocky 2 to 4 feet 1 Massive Greater than 4 feet 1 GEODESIGN ROCK CLASSIFICATION GUIDELINES TABLE A -3 1 I. DEPTH /FT MATERIAL DESCRIPTION TESTING 1� TP -1 0 - AC ASPHALT CONCRETE (1 -inch thick). I 1 - GM -FILL Medium dense, gray GRAVEL FILL with some sand and trace silt; dry to moist (1 -inch thick root zone). 2- PP= 2.5TSF ML Very stiff, dark gray SILT with trace fine sand and organics; moist. 3 - grades to green -gray with some fine sand at 2.5 feet 1 4- PP= 2.0TSF 5- PP = 2.5 T5F 1 6- 7 - grades to orange -light brown and gray, sandy with some boulders at 7.0 feet 8- 1 9 10 ' 1 1 - CH Medium stiff to stiff, red -brown CLAY with some silt and gravel; moist. 12- 13 I 14 - Test pit completed at 13.0 feet due to refusal on hard rock on August 14, 2001. Disturbed sample obtained at 2.0 feet. No groundwater seepage observed to the depth explored. 15 - No caving observed to the depth explored. 1 , TP -2 0- ' ML Hard, orange -gray SILT with trace to some day and organics; dry to moist (2 -inch thick root zone). 1- 2 - grades to hard, orange -gray and dark brown with trace organics at 2.0 feet 1 3 - PP = 4.5 TSF 4 - 1 5- subrounded boulders encountered at 5.5 feet PP = 4.5 TSF 6- 7 CH Hard, dark red - brown, gravelly CLAY; moist. 8- 9- II 10 - .Test pit completed at 9.5 feet due to refusal on hard rock on August 14, 2001. Disturbed samples obtained at 3.0, 5.5, 8.0 and 9.5 feet. 11 - No groundwater seepage observed to the depth explored. No caving observed to the depth explored. 12- 1 13- 14- 1 15- 1 TEST PIT LOGS i GEbDESIGN z PNWP -30 SEPTEMBER 2001 FIGURE A -1 1 1 DEPTH /FT MATERIAL DESCRIPTION TESTING TP -3 1 0- ML Hard, gray SILT with some clay and trace organics; dry to moist (1.5 -inch thick root zone). 1- 2- 3- 4 1 5- 6 - boulder encountered at 6.0 feet 7 8 - CH Stiff, red -brown CLAY with some silt and angular gravel; moist. 9 1 Test pit completed at 9.0 feet due to refusal on hard rock (boulder?) on August 14, 2001. 10 - Disturbed samples obtained at 4.0, 5.0 and 8.5 feet. No groundwater seepage observed to the depth explored. 11 - No caving observed to the depth explored. 12- 13- 1 14- 15- 1 1 1 1 1 1 1 1 1 TEST PIT LOGS GEO 1 PNWP -30 SEPTEMBER 2001 FIGURE A -2 1 r - D - EFTH/FT MATERIAL DESCRIPTION TESTING TP -4 0- ML Medium stiff, orange -light brown SILT with trace to some fine sand; moist (1 -inch thick root 1 1 - zone). 2- 3- 4- 5- II 6- t -. 7- 8 - becomes red with trace to some clay and gravel at 8.0 feet 9 CH Medium stiff to stiff, red -brown CLAY with some silt and gravel moist. 10 1 1 1 RK Very soft to soft (RH -0 to RH -1), weak, moderate to severely weathered, closely fractured 12 - BASALT. 1 13- 14- E - 1 - pit completed at 17.0 feet on August 14, 2001. ' 18 - Disturbed samples obtained at 5.0, 10.0 and 14.0 feet. No groundwater seepage observed to the depth explored. 19 - No caving observed to the depth explored. 20 - 1 21 - 22 - 1 23 - 24 - 25 II 1 1 1 1 G Eo DESIG u TEST PIT LOGS 1 N z PNWP -30 SEPTEMBER 2001 FIGURE A -3 1 1 ; : ' 1 APPENDIX C 1 PREVIOUS FIELD EXPLORATIONS BY GEOPACIFIC ENGINEERING, INC. GEI explored subsurface conditions at the site in a previous investigation by excavating five test pits in the northern and eastern portions of the site. Test pits were excavated in September 2001 using methods similar to those described in Appendix A. The approximate location of the explorations is included on the site plan in Appendix B. 1 1 1 1 1 1 1 1 1 1 1 1 1 G EODESIGN? C -1 PNWP- 30- 02:071905 ',V > GEOP ACIFlC ENGINEERING, INC. 17700 SW Upper 97 Boones Ferry Road, Suite 100 T EST PIT LOG Portland, ES ' Tel: (503) 598 -8445 Fax: (503) 598 -8705 Project: Root Office Building Project No. 01 -7186 1 Tigard, Oregon Project Test Pit No. TP-1 o„^ 2 c Y o 1- � c� .r" � N n o: c n X13% =°.5 10 c o a. 22 E_ �° M o Material Description d V m 1 Organic SILT (OL), dark brown, many coarse roots to 16 inches, moist (Topsoil) 1 0.75 1 2 2.0 Stiff SILT (ML), gray, leached, damp to moist (Soil A- Horizon) I 3 >4.5 Hard, clayey SILT (ML), strongly mottled Tight orange -brown and gray, common 4 >4 day seams, damp (Soil B- Horizon grading to Willamette Formation) 1,5 I Hard (R4) BASALT, gray 7 I Practical Refusal @ 6 to 7 feet on Hard (R4) to Very Hard (R5) BASALT 8 I g Note: No seepage or groundwater encountered. Very slow digging below 3 feet 10 1 112 ' 13 14 1 15 116 17 LEGEND 0 1 1.°0O4 Date Excavated: 3/8/01 s — Ai e ® ' Logged By. PAC Bucket Sample Elevation: Bag Sample eud Sample Shelby Tube Sample Seepage Water Bearing Zone Water Level at Abandonment 1 r GEOP ' . r,, ACIFlC ENGINEERING, INC. _. dove. , 17700 SW *A Portland Oregon 97224 Ferry Road, Suite 100 TEST PIT LOG "Il . Tel (503) 598 -8445 Fax: (503) 598 -8705 ' Project Root Office Building Project No. 01 -7186 Tigard, Oregon Test Pit No. TP -2 1 B a Z• c m g g F - 2-2g g , '64 t. 8.2 a 2° 15'2 W Material Description 1 p a.c m SZ' 3 W a CO v m Organic SILT (OL), dark brown, many coarse roots to 16 inches, moist (Topsoil) 1 1 1.0 Stiff. SILT (ML), mottled gray and orange, leached, damp to moist I 2 1.5 (Soil A- Horizon) >4.5 Hard, clayey SILT (ML), strongly mottled light brown, orange and gray, common 4 >4.5 clay seams, dry to clamp (Soil B- Horizon grading to Willamette Formation) 5 Hard (R4) BASALT, gray 6 Practical Refusal @ 5 to 6 feet on Hard (R4) to Very Hard (R5) BASALT 7 )$ 1 g Note: No seepage or groundwater encountered. Very slow digging 1 below 3 feet 10 11 1 12 1 13 14 15 1 16 1 17 LEGEND 1 Date Excavated: 3/8/01 100 to P iiii ii a Logged By: PAC 1 1,D00 g Bag Sample Bucket Sample Tube Sample Seepage Water Surface Elevation: wring Zone Water Level at Abandonment 1 -° = ,f GEOPACIFlC ENGINEERING, INC. 17700 SVV Oregon 87224 Ferry Road, Suite 100 TEST P' 1 ®^ 1 ". Tel: (503) 598 -8445 Fax: (503) 598 -8705 E LOG Project: Root Office Building Project No. 01 -7186 Test Pit No. TP -3 1 Tigard, Oregon a m * c v to « T y "ii..... F. v. ,.. ° -. Y � �� ..c ir o a v z� t o m Material Description is N 0 U m 1 — 314'4 crushed aggregate (Fill) I — 1-inch to 4 inch diameter river rock with silt matrix (Fill) 2— _ 1.5 Organic SILT (OL -ML), dark brown, no roots or coarse organic (Topsoil) I 3- 3.0 Very stiff, clayey SILT (ML), mottled orange and gray, moist (Soil A- Horizon) 4— 3.5 I — Very stiff, clayey SILT (ML), mottled light orange -brown and gray, damp _ (Soil B- Horizon) 1 6— Test Pit Terminated @ 5.5 feet 7— Note: No seepage or groundwater encountered. I 8- 1 9— 10— 1 11- 112- 1 13— 14- 115 1 17 LEGEND o Date Excavated: 3/8/01 1 ,00 w E 7 Logged By: PAC Surface Elevation: Ba9 ode Bucket Sample Selby Tube Sample Seepage Water Bearing Zone Water level at Abandonment 1 GEOPACIFlC ENGINEERING, INC. "Illfr 0 •_,..., r 17700 SW Upper Boones Ferry Road, Suite 100 C LOG r� o. Portland. Oregon 97224 TEST PIT L ®V 1 Tel (503) 598 -8445 Fax (503) 598 -8705 Project: Root Office Building Project No. 01 -7186 Test Pit No. TP-4 Tigard, Oregon I F- m 0 mE� �c" m o N ft 15 0 ° a 1 5 0 _49 W` W m Material Description n. to ° v m E 1 1/4 inch to 3 inch diameter rock with silt matrix (Embankment Fill) 2 3 -inch pipe line @ 2 feet 1 3 2.5 Very stiff, clayey SILT (ML), mottled gray and orange, damp 1 (Soil A- Horizon) 4 5 Test Pit Terminated @ 4.5 feet 1 6 Note: No seeps or groundwater encountered. 7 1 • I 10 1 11 12 1 13 I 14 15 1 16 1 17 i LEGEND a Date Excavated: 3/8/01 A E 7 Logged By: PAC I 10010 til 1.000 Surface Elevation: Bag Sample Bucket Sample Shelby Tube Sample Seepage Water Bearing Zone Water Level at Abandonment 1 /.. - GEOPACIFIC ENGINEERING, INC. 17700 SW Upper Boones Ferry Road, Suite 100 Portland, Oregon 97224 TEST PIT LOC' "P : Tel: (503) 598 -8445 Fax: (503) 598 -8705 Project: Root Office Building Project No. 01 -7186 Test Pit No. TP -5 Tigard, Oregon ii m m .-, T z' ,,,F 0 ` , m cg l. F- .. 2 ., � N U Y O m fi C a E � i° c Material Description 6.> p m N O o m a P - Organic SILT (OL), dark brown, many roots to 16 inches (Topsoil) 1- 0.75 1 2— 2 5 Very stiff to hard, clayey SILT (ML), mottled orange and gray, damp and moist (Soil A- Horizon) 1 3 = >4.5 4— >4.5 5— Hard, clayey SILT (ML), strongly mottled , common light brown, orange and gray, m9 9 9 Y day seams, dry to damp (Soil 13- Horizon grading to Willamette Formation) 1 6= • 8 Test Pit Terminated @ 8 feet 1 9— Note: No seeps or groundwater encountered. Very slow digging below 1 10= 3 feet 11- 112- 1 13 14— 1 151 16— • 17 - . LEGEND 1 Date Excavated: 3/8/01 9 //Ili ® Logged By: PAC 7 Surface Elevation: Bas Sample Bucket sample Shelby rube sae Seepage water Bearing Zone Water Level at Abandonment 1� sample