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Report L029G - DOOoy 9750 SW Nimbus Avenue Beaverton, OR 97008-7172 1Ht1'c)Ars =. p 1 503 641 3478 f) 503 644-8034 OFFICE COPY Sw June 28, 2017 RECEIVED 5970-CGEOTECHNICALRPT Tigard-Tualatin School District FEB 1 0 2021 6960 SW Sandburg Street Tigard, OR 97223 CITY OF TIGARD Attention: Debbie Pearson/DAY CPM Services L �JILDING DIVISION SUBJECT: Geotechnical Investigation and Site-Specific Seismic-Hazard Evaluation Templeton Elementary School Tigard, Oregon At your request, GRI completed a geotechnical investigation and site-specific seismic hazard evaluation for the planned improvements at Templeton Elementary School in Tigard, Oregon. The Vicinity Map, Figure 1, shows the general location of the site. The purpose of the investigation was to evaluate subsurface conditions at the site and develop geotechnical recommendations for use in the design and construction of the proposed improvements. The investigation included a review of existing geotechnical information for the site and surrounding area, subsurface explorations, laboratory testing, and engineering analyses. As part of our investigation, GRI completed a site-specific seismic-hazard evaluation to satisfy the requirements of the 2012 International Building Code (IBC), which was adopted by the 2014 Oregon Structural Specialty Code (OSSC). This report describes the work accomplished and provides conclusions and recommendations for use in the design and construction of the proposed project. PROJECT DESCRIPTION We understand the existing Templeton Elementary School will be demolished and rebuilt under the 2016 Tualatin-Tigard School District Bond Program. The existing Community Building located north of the existing Templeton Elementary School will remain in its current configuration for this project. The Site Plan, Figure 2, shows the location of the existing school, Community Building, and associated improvements. Based on our review of conceptual plans, we understand the new school will have a partially embedded lower level that will daylight near the southern property boundary. The northern and eastern portions of the first floor will be constructed at grade, and the remainder of the first floor will be constructed above the lower level. In general, the northern and eastern portions of the building will be located within the existing building footprint and the southern portion will extend about 150 ft south of the existing building. Although structural loads for the new building are not currently available, we anticipate column and wall loads will be on the order of 100 to 200 kips and 3 to 4 kips/ft, respectively. We anticipate the finished floor elevation for the lower level will be established at or near the lowest existing site grade, which occurs near the southern property boundary. Based on our review of topographic maps provided by the client, we estimate an excavation of about 5 to 10 ft will be required to construct the partially embedded lower level. We anticipate the finished floor elevation for the first floor will generally be consistent with existing site grades, and cuts and fills to establish grade across the remainder of the site will be minimal. Providing geotechnical,pavement,and environmental consulting services since 1984 fi We understand a new bus loop will surround the new school on the east and south, and a new service road and parking areas will be constructed around the existing Community Building. We anticipate the new bus loop and parking areas will be paved with asphalt concrete (AC) pavement, and areas subjected to frequent heavy truck traffic, such as trash-enclosure and service areas, will be paved with Portland cement concrete (PCC) pavement SITE DESCRIPTION General The existing Templeton Elementary School consists of four, independent buildings that will be demolished for this project. The existing school buildings are bordered by a parking lot, bus loop and drop-off area, and the Community Building on the north; a grass field and play areas on the east and south; and residential structures on the west. The Community Building and parking lot will remain in their current configuration for this project. The new bus loop will be constructed between the new school and residential structures, and the new service road and parking areas will be constructed within the footprint of the two easternmost school buildings. Review of satellite imagery and our observations at the site indicate the ground surface gently slopes downward from northwest to southeast across the site; however, the grass field and play areas are recessed about 5 ft lower than the existing school buildings and are separated by an approximate 5H:1V (Horizontal to Vertical) slope. Geology Published geologic mapping indicates the site is mantled with Missoula flood deposits, locally referred to in the project area as the Willamette Silt Formation (Madin, 1990). In general, Willamette Silt is composed of unconsolidated beds and lenses of silt and sand. Stratification within this formation commonly consists of 4-to 6-in.-thick beds, although in some areas, the silt and sand are massive and the bedding is indistinct or nonexistent. Based on the explorations completed for this project, the Willamette Silt is underlain by Columbia River Basalt at depths of about 41.5 to 75 ft at the site. SUBSURFACE CONDITIONS General Subsurface materials and conditions at the site were investigated between May 3 and May 5, 2017, with three borings, designated B-1 through B-3; three cone penetrometer test (CPT) soundings, designated CPT-1 through CPT-3; and one dilatometer(DMT) sounding, designated DMT-1. The borings were advanced to a depth of about 41.5 ft, the CPT probes to depths of about 42.3 to 76.3 ft, and the DMT sounding to a depth of about 39 ft below existing site grades. The approximate locations of the explorations completed for this investigation are shown on Figure 2. Logs of the borings, CPT probes, and DMT sounding are provided on Figures 1A through 9A. The field and laboratory programs conducted to evaluate the physical engineering properties of the materials encountered in the explorations are described in Appendix A. The terms and symbols used to describe the materials encountered in the explorations are defined on Tables 1A through 3A and in the attached legend. In addition, GRI is completing a concurrent geotechnical investigation for Twality Middle School located immediately northwest of Templeton Elementary School. As part of our Twality Middle School investigation, three borings, designated B-1TW through B-3TW; one CPT probe, designated CPT-1TW; and one DMT sounding, designated DMT-1TW, were completed between May 3 and May 5, 2017. The Rp 2 borings were advanced to depths of about 27.8 to 51.5 ft, the CPT probe to a depth of about 26.3 ft, and the DMT sounding to a depth of about 34 ft below existing site grades at the approximate locations shown on Figure 2. Logs of the explorations and results of laboratory testing completed for the Twality Middle School project are included in Appendix B for reference. Sampling Disturbed and undisturbed soil samples were obtained from the borings at 2.5-ft intervals of depth in the upper 15 ft, 5-ft intervals to a depth of 30 ft, and 5- to 10-ft intervals below 30 ft. Disturbed soil samples were obtained using a 2-in.-outside-diameter (O.D.) standard split-spoon sampler (SPT). Penetration tests were conducted by driving the samplers into the soil a distance of 18 in. using a 140-lb hammer dropped 30 in. The number of blows required to drive the SPT sampler the last 12 in. is known as the Standard Penetration Resistance, or SPT N-value. SPT N-values provide a measure of the relative density of granular soils and the relative consistency of cohesive soils. Relatively undisturbed soil samples were collected by pushing a 3-in.-O.D. Shelby tube into the undisturbed soil a maximum of 24 in. using the hydraulic ram of the drill rig. The soil in the Shelby tubes was extruded in our laboratory and Torvane shear strength measurements were recorded on selected samples. Soils For the purpose of discussion, the materials disclosed by our investigation have been grouped into the following categories based on their physical characteristics and engineering properties: 1. PAVEMENT 2. Sandy SILT and Silty SAND 3. SILT and CLAY 4. BASALT The following paragraphs provide a detailed description of the materials encountered in the explorations and a discussion of the groundwater conditions at the site. 1. PAVEMENT. Exploration DMT-1 was advanced in an existing paved area and encountered approximately 3 in. of AC pavement at the ground surface. The pavement is underlain by about 10 in. of crushed-rock base (CRB) course. 2. Sandy SILT and Silty SAND. Interbedded layers of sandy silt and silty sand were encountered at the ground surface in explorations B-1 through B-3 and CPT-1 through CPT-3 and beneath pavement in exploration DMT-1. The interbedded layers of silt and sand extend to depths of about 38 to 58 ft. The thicknesses of the interbedded layers typically range from about 2 in. to 10 ft; however, layers of silty sand up to 35 ft thick were encountered in explorations B-1 and B-2. The soils are generally dark brown to brown with varying degrees of rust mottling and grade to gray below a depth of 30 to 35 ft. In general, the sandy silt contains fine-to medium-grained sand and up to trace clay; and the silty sand is fine to medium grained. The natural moisture contents of the silt and sand soils range from 24 to 39% and 24 to 35%, respectively. The relative consistency of the sandy silt is soft to hard based on SPT N-values of 4 to 12 blows/ft, Torvane shear strength values of 0.40 to 0.50 tsf, CPT tip-resistance values of about 5 to 210 tsf, and DMT GRD 3 constrained modulus values of about 120 to 1,000 tsf and is typically medium stiff. The relative density of the silty sand is very loose to very dense based on SPT N-values of 4 to 33 blows/ft, CPT tip-resistance values of about 10 to 290 tsf, and DMT constrained modulus values of about 375 to 1,500 tsf and is typically medium dense. It should be noted the borings were completed using solid-stem auger drilling techniques and SPT N-values tend to be underestimated in sandy soils below the groundwater level using this drilling method. Explorations B-1 through B-3 and DMT-1 were terminated in sandy silt to silty sand at depths of about 39 to 41.5 ft 3. SILT and CLAY. Interbedded layers of silt and clay were encountered beneath interbedded layers of silty sand and sandy silt based on interpretations of explorations CPT-1 through CPT-3. The interbedded layers of silt and clay extend to depths of about 41.5 to 75 ft. The thicknesses of the interbedded layers range from about 2 in. to 5 ft. The silt has a variable clay content ranging from a trace of clay to clayey, and the clay has a variable silt content ranging from a trace of silt to silty. Typically, the silt is clayey and the clay is silty. The silt and clay contain a variable amount of fine-grained sand, ranging from a trace of sand to sandy, and are interbedded with layers of sand ranging in thickness from 1 to 3 in. at depths of 55 and 60 ft in CPT-2. The relative consistency of the silt and clay soils is stiff to hard based on CPT tip-resistance values of about 15 to 240 tsf and is typically stiff to very stiff. 4. BASALT. Extremely soft (RO) basalt of the Columbia River Basalt Group was encountered beneath interbedded layers of silt and clay based on interpretations of explorations CPT-1 through CPT-3 and our experience in the project vicinity. The basalt extends to the maximum depth explored of 76 ft and is likely predominantly decomposed to decomposed. CPT tip-resistance values of about 150 to 500 tsf were recorded in the basalt. Explorations CPT-1 through CPT-3 were terminated in basalt at depths of about 42 to 76 ft. Groundwater Our review of U.S. Geological Survey (USGS) groundwater data suggests the regional groundwater level at the site typically occurs at depth in the highly fractured, hard basalt that underlies the site. However, groundwater was encountered at depths of 8 to 10 ft below the ground surface in borings B-1 through B-3. Explorations completed for this project and our experience in the project vicinity indicate perched groundwater occurs in the silt and sand soils that mantle the site throughout the year. We anticipate the local perched groundwater level typically occurs at a depth of 15 to 20 ft below the ground surface during the normally dry summer and fall months and may approach the ground surface during the wet winter and spring months or during periods of heavy or prolonged precipitation. CONCLUSIONS AND RECOMMENDATIONS General Subsurface explorations completed for this investigation indicate the site is mantled with interbedded layers of medium-stiff sandy silt and medium-dense silty sand. The interbedded layers of sandy silt and silty sand extend to depths of 38 to 58 ft and are underlain by interbedded layers of stiff to very stiff silt and clay. Based on our interpretation of CPT data and our experience in the project vicinity, we estimate basalt underlies the site at depths of 42 to 76 ft. We anticipate the local perched groundwater level typically occurs at depths of 15 to 20 ft below the ground surface throughout the year; however, perched groundwater may approach the ground surface during the wet winter months and following periods of intense or prolonged precipitation. GRO 4 In our opinion, foundation support for new structural loads can be provided by conventional spread and wall foundations established in firm, undisturbed, native soil or compacted structural fill. The primary geotechnical considerations associated with construction of the proposed building and associated improvements include the presence of fine-grained soils at the ground surface that are extremely sensitive to moisture content and the potential for shallow, perched groundwater conditions. The following sections of this report provide our conclusions and recommendations for use in the design and construction of the project. Seismic Considerations General. We understand the project will be designed in accordance with the 2012 IBC with 2014 OSSC modifications. For seismic design, the 2012 IBC references the American Society of Civil Engineers (ASCE) document 7-10, titled "Minimum Design Loads for Buildings and Other Structures" (ASCE 7-10). A site- specific seismic-hazard evaluation was completed for the project in accordance with the 2014 OSSC. Details of the site-specific seismic-hazard evaluation and the development of the recommended response spectra are provided in Appendix C. Code Background. The 2012 IBC and ASCE 7-10 seismic hazard levels are based on a Risk-Targeted Maximum Considered Earthquake (MCER), with the intent of including the probability of structural collapse. The ground motions associated with the probabilistic MCER represent a targeted risk level of 1% in 50 years probability of collapse in the direction of maximum horizontal response with 5% damping. In general, these risk-targeted ground motions are developed by applying adjustment factors of directivity and risk coefficients to the 2% probability of exceedance in 50 years, or 2,475-year return period, hazard level (MCE) ground motions developed from the 2014 USGS Unified Hazard Tool. The risk-targeted probabilistic values are also subject to a deterministic limit. The code-based, ground-surface, MCER-level spectrum is typically developed using the mapped bedrock spectral accelerations, Ss and Si, and corresponding site coefficients, Fa and Fv,to account for site soil conditions. Site Response. In accordance with Section 20.4.2 of ASCE 7-10, the site is classified as Site Class D, or a stiff-soil site, based on an estimated Vs30of about 950 ft/sec in the upper 100 ft of the soil profile. However, our analysis has identified a potential risk of seismically induced settlement at the site. In accordance with ASCE 7-10, sites with soils vulnerable to failure or collapse under seismic loading should be classified as Site Class F, which requires a site-specific site-response analysis unless the structure has a fundamental period of vibration less than or equal to 0.5 sec. The design response spectrum for sites with structures having a fundamental period of less than or equal to 0.5 sec can be derived using the non-liquefied subsurface profile. For periods greater than 0.5 sec, the code requires a minimum spectral response value equal to 80% of Site Class E. We anticipate the new structure will have a fundamental period of less than 0.5 sec; therefore, the code- based Site Class D conditions are appropriate for design of the structure. The maximum horizontal- direction spectral response accelerations were obtained from the USGS Seismic Design Maps for the coordinates of 45.4124° N latitude and 122.7740° W longitude. The Ss and Si parameters identified for the site are 0.96 and 0.42 g, respectively, for Site Class B or bedrock conditions. To establish the ground- surface MCER spectrum, these bedrock spectral coefficients are adjusted for site class using the short- and long-period site coefficients, Fa and Fv, in accordance with Section 11.4.3 of ASCE 7-10. The design-level response spectrum is calculated as two-thirds of the ground-surface MCER spectrum. V RU5 The recommended MCER- and design-level spectral response parameters for Site Class D conditions are tabulated below and discussed in further detail in Appendix C. RECOMMENDED SEISMIC DESIGN PARAMETERS(2012 IBC/2014 OSSC) Recommended Seismic Parameter Value Site Class D MCER 0.2-Sec Period 1.07 g Spectral Response Acceleration, SMs MCER 1.0-Sec Period 0.66 g Spectral Response Acceleration,SM, Design-Level 0.2-Sec Period 0.72 g Spectral Response Acceleration, Sos Design-Level 1.0-Sec Period 0.44 g Spectral Response Acceleration, So, Liquefaction/Cyclic Softening. Liquefaction is a process by which loose, saturated granular materials, such as clean sand and, to a somewhat lesser degree, non-plastic and low-plasticity silts, temporarily lose stiffness and strength during and immediately after a seismic event. This degradation in soil properties may be substantial and abrupt, particularly in loose sands. Liquefaction occurs as seismic shear stresses propagate through a saturated soil and distort the soil structure, causing loosely packed groups of particles to contract or collapse. If drainage is impeded and cannot occur quickly, the collapsing soil structure causes the pore- water pressure to increase between the soil grains. If the pore-water pressure becomes sufficiently large, the inter-granular stresses become small and the granular layer temporarily behaves as a viscous liquid rather than a solid. After liquefaction is triggered, there is an increased risk of settlement, loss of bearing capacity, lateral spreading, and/or slope instability, particularly along waterfront areas. Liquefaction-induced settlement occurs as the elevated pore-water pressures dissipate and the soil consolidates after the earthquake. Cyclic softening is a term that describes a relatively gradual and progressive increase in shear strain with load cycles. Excess pore pressures may increase due to cyclic loading but will generally not approach the total overburden stress. Shear strains accumulate with additional loading cycles, but an abrupt or sudden decrease in shear stiffness is not typically expected. Settlement due to post-seismic consolidation can occur, particularly in lower-plasticity silts. Large shear strains can develop, and strength loss related to soil sensitivity may be a concern. The potential for liquefaction and/or cyclic softening is typically estimated using a simplified method that compares the cyclic shear stresses induced by the earthquake (demand) to the cyclic shear strength of the soil available to resist these stresses (resistance). Estimates of seismically induced stresses are based on earthquake magnitude and peak ground-surface acceleration (PGA). The cyclic resistance of soils is dependent on several factors, including the number of loading cycles, relative density, confining stress, plasticity, natural water content, stress history, age, depositional environment (fabric), and composition. The cyclic resistance of soils is evaluated using in-situ testing in conjunction with laboratory index testing but may also include monotonic and cyclic laboratory strength tests. For sand-like soils, the cyclic resistance is typically evaluated using SPT N-values or CPT tip-resistance values normalized for overburden pressures and corrected for factors that influence cyclic resistance, such as fines content. For clay-like soils, GRU 6 the cyclic resistance is typically evaluated using estimates of the undrained shear strength, overconsolidation ratio (OCR), and sensitivity, or directly from cyclic laboratory tests. The potential for liquefaction and/or cyclic softening at the site was evaluated using the simplified method based on procedures recommended by Idriss and Boulanger (2008) with subsequent revisions (2014). This method utilizes the PGA to predict the cyclic shear stresses induced by the earthquake. The USGS National Seismic Hazard Mapping Project (NSHMP) was used to determine the contributing earthquake magnitudes that represent the seismic exposure of the site for the MCEc hazard level. A crustal event on the Portland Hills fault and an event on the Cascadia Subduction Zone (CSZ) were determined to represent the sources of seismic shaking. For our evaluation, we have considered a magnitude MW 7 crustal earthquake and MW 9 CSZ earthquake with code-level PGAs (PGAM) of 0.45 and 0.36 g, respectively. We have conservatively assumed a groundwater depth of about 10 ft below the ground surface, which corresponds to the anticipated highest sustained groundwater level at the site. The results of our evaluation indicate there is a potential that zones of the interbedded sandy silt and silty sand deposit below the groundwater surface at the site could lose strength or liquefy during a code-based earthquake. Based on our analysis, potentially liquefiable soils are present about 10 ft below the ground surface and extend to a depth of about 40 ft. Our analysis indicates the potential for 1 to 2 in. of seismically induced settlement, which may occur during the earthquake and after earthquake shaking has ceased. Conventional geotechnical practice is to assume differential settlements may approach 50% of the calculated total seismic settlement. Discussion of seismically induced building foundation settlement is presented in the Foundation Support section later in this report. Other Seismic Hazards. Based on site topography, the risk of earthquake-induced slope instability and/or lateral spreading is low. The risk of damage by tsunami and/or seiche at the site is absent. The inferred location of the Canby-Mollala Fault underlies the site (Personius et al., 2003); however, the USGS does not consider the Canby-Mollala Fault to be an active, contributing source in their Probabilistic Seismic Hazard Analysis (PSHA). The USGS considers the Portland Hills Fault, located about 12 km northeast of the site, to be the closest crustal fault source contributing to the overall seismic hazard at the site. Unless occurring on a previously unmapped or unknown fault, the risk of fault rupture at the site is low. Earthwork General. The fine-grained soils that mantle the site are sensitive to moisture, and perched groundwater may approach the ground surface during the wet winter months. Therefore, it is our opinion earthwork can be completed most economically during the dry summer months, typically extending from June to mid-October. It has been our experience that the moisture content of the upper few feet of silty soils will decrease during extended warm, dry weather. However, below this depth, the moisture content of the soil tends to remain relatively unchanged and well above the optimum moisture content for compaction. As a result, the contractor must use construction equipment and procedures that prevent disturbance and softening of the subgrade soils. To minimize disturbance of the moisture-sensitive silt soils, site grading can be completed using track-mounted hydraulic excavators. The excavation should be finished using a smooth-edge bucket to produce a firm, undisturbed surface. It may also be necessary to construct granular haul roads and work pads concurrently with excavation to minimize subgrade disturbance. If the subgrade is disturbed during construction, soft, disturbed soils should be overexcavated to firm soil and backfilled with structural fill. GRU 7 If construction occurs during wet ground conditions, granular work pads will be required to protect the underlying silt subgrade and provide a firm working surface for construction activities. In our opinion, a 12-to 18-in.-thick granular work pad should be sufficient to prevent disturbance of the subgrade by lighter construction equipment and limited traffic by dump trucks. Haul roads and other high- density traffic areas will require a minimum of 18 to 24 in. of fragmental rock, up to 6-in. nominal size, to reduce the risk of subgrade deterioration. The use of a geotextile fabric over the subgrade may reduce maintenance during construction. Haul roads can also be constructed by placing a thickened section of pavement base course and subsequently spreading and grading the excess CRB after earthwork is complete. As an alternative to the use of a thickened section of crushed rock to support construction activities and protect the subgrade, the subgrade soils can be treated with cement. It has been our experience in this area that treating the silt soils to a depth of 12 to 14 in. with about a 6 to 8% admixture of cement overlain by 6 to 12 in. of crushed rock will support construction equipment and provide a good, all-weather, working surface. Site Preparation. Demolition of the existing improvements within the limits of the proposed improvements should include removal of existing pavements, floor slabs, foundations, walls, and underground utilizes (if present). The ground surface within all building areas, paved areas, walkways, and areas to receive structural fill should be stripped of existing vegetation, surface organics, and loose surface soils. We anticipate stripping up to a depth of about 4 to 6 in. will likely be required in the grass field and play areas near the southern and eastern property boundaries; however, deeper grubbing may be required to remove brush and tree roots. All demolition debris, trees, brush, and surficial organic material should be removed from within the limits of the proposed improvements. Excavations required to remove existing improvements, brush, and trees should be backfilled with structural fill. Organic strippings should be disposed of off site, or stockpiled on site for use in landscaped areas. Following stripping or excavation to subgrade level, the exposed subgrade should be evaluated by a qualified geotechnical engineer or engineering geologist. Proof rolling with a loaded dump truck may be part of this evaluation. Any soft areas or areas of unsuitable material disclosed by the evaluation should be overexcavated to firm material and backfilled with structural fill. Due to previous development at the site, it should be anticipated some overexcavation of subgrade will be required. Excavation. We estimate an excavation of about 5 to 10 ft will be required to found the partially embedded lower level. Temporary excavation slopes should be no steeper than about 1 H:1 V, and permanent cut and fill slopes should be no steeper than 2H:1V. It should be understood the steeper the temporary slopes, the more risk there is of sloughing of the exposed surface during construction. In our opinion, the short-term stability of temporary slopes will be adequate if surcharge loads due to existing footings, construction traffic, vehicle parking, material laydown, etc., are maintained an equal distance to the height of the slope away from the top of the open cut. Other measures that should be implemented to reduce the risk of localized failures of temporary slopes include (1) using geotextile fabric to protect the exposed cut slopes from surface erosion; (2) providing positive drainage away from the top and bottom of the cut slopes; (3) constructing and backfilling walls as soon as practical after completing the excavation; (4) backfilling overexcavated areas as soon as practical after completing the excavation; and (5) periodically monitoring the area around the top of the excavation for evidence of ground cracking. It must be emphasized that following these recommendations will not guarantee sloughing or movement of the GRO 8 temporary cut slopes will not occur; however, the measures should serve to reduce the risk of a major slope failure. It should be realized, however, that blocks of ground and/or localized slumps may tend to move into the excavation during construction. Depending on the depth of the excavation and the time of year the work is completed, perched groundwater may be encountered in the excavation. We anticipate seepage, if encountered, can be controlled by pumping from temporary sumps in the bottom of the excavation. A blanket of relatively clean, well-graded crushed rock placed on the slopes may be required to reduce the risk of raveling soil conditions if temporary excavation slopes encounter perched groundwater. The thickness of the granular blanket should be evaluated based on actual conditions but would likely be in the range of 12 to 24 in. Structural Fill. We anticipate minor amounts of structural fill will be placed for this project. We recommend structural fill consist of granular material, such as sand, sandy gravel, or crushed rock with a maximum size of 2 in. Granular material that has less than 5% passing the No. 200 sieve (washed analysis) can usually be placed during periods of wet weather. Granular backfill should be placed in lifts and compacted with vibratory equipment to at least 95% of the maximum dry density determined in accordance with ASTM D698. Appropriate lift thicknesses will depend on the type of compaction equipment used. For example, if hand-operated vibratory-plate equipment is used, lift thicknesses should be limited to 6 to 8 in. If smooth-drum vibratory rollers are used, lift thicknesses up to 12 in. are appropriate, and if backhoe- or excavator-mounted vibratory plates are used, lift thicknesses of up to 2 ft may be acceptable. On-site, fine-grained soils and site strippings free of debris may be used as fill in landscaped areas. These materials should be placed at about 90% of the maximum dry density as determined by ASTM D698. The moisture contents of soils placed in landscaped areas are not as critical, provided construction equipment can effectively handle the materials. Utility Excavations. In our opinion, there are three major considerations associated with design and construction of new utilities. 1) Provide stable excavation side slopes or support for trench sidewalls to minimize loss of ground. 2) Provide a safe working environment during construction. 3) Minimize post-construction settlement of the utility and ground surface. The method of excavation and design of trench support are the responsibility of the contractor and subject to applicable local, state, and federal safety regulations, including the current Occupational Safety and Health Administration (OSHA) excavation and trench safety standards. The means, methods, and sequencing of construction operations and site safety are also the responsibility of the contractor. The information provided below is for the use of our client and should not be interpreted to mean we are assuming responsibility for the contractor's actions or site safety. According to current OSHA regulations, the majority of the fine-grained soils encountered in the explorations may be classified as Type B. In our opinion, trenches less than 4 ft deep that do not encounter groundwater may be cut vertically and left unsupported during the normal construction sequence, GRU 9 assuming trenches are excavated and backfilled in the shortest possible sequence and excavations are not allowed to remain open longer than 24 hr. Excavations more than 4 ft deep should be laterally supported or alternatively provided with side slopes of 1 H:1 V or flatter. In our opinion, adequate lateral support may be provided by common methods, such as the use of a trench shield or hydraulic shoring systems. We anticipate the groundwater level will typically occur below the anticipated maximum excavation depth; however, perched groundwater may approach the ground surface during intense or prolonged precipitation. Groundwater seepage, running soil conditions, and unstable trench sidewalls or soft trench subgrades, if encountered during construction, will require dewatering of the excavation and trench sidewall support. The impact of these conditions can be reduced by completing trench excavations during the summer months, when groundwater levels are lowest, and by limiting the depths of the trenches. We anticipate groundwater inflow, if encountered, can generally be controlled by pumping from sumps. To facilitate dewatering, it will be necessary to overexcavate the trench bottom to permit installation of a granular working blanket. We estimate the required thickness of the granular working blanket will be on the order of 1 ft, or as required to maintain a stable trench bottom. The actual required depth of overexcavation will depend on the conditions exposed in the trench and the effectiveness of the contractor's dewatering efforts. The thickness of the granular blanket must be evaluated on the basis of field observations during construction. We recommend the use of relatively clean, free-draining material, such as 2- to 4-in.-minus crushed rock, for this purpose. The use of a geotextile fabric over the trench bottom will assist in trench-bottom stability and dewatering. All utility trench excavations within building and pavement areas should be backfilled with relatively clean, granular material, such as sand, sandy gravel, or crushed rock of up to 11/2-in. maximum size and having less than 5% passing the No. 200 sieve (washed analysis). The bottom of the excavation should be thoroughly cleaned to remove loose materials and the utilities should be underlain by a minimum 6-in. thickness of bedding material. The granular backfill material should be compacted to at least 95% of the maximum dry density as determined by ASTM D698 in the upper 5 ft of the trench and at least 92% of this density below a depth of 5 ft. The use of hoe-mounted vibratory-plate compactors is usually most efficient for this purpose. Flooding or jetting as a means of compacting the trench backfill should not be permitted. Foundation Support We anticipate column and wall loads will be on the order of 100 to 200 kips and 3 to 4 kips/ft, respectively. In our opinion, the proposed structural loads can be supported on conventional spread and wall footings in accordance with the following design criteria. As discussed earlier, our analysis indicates 1 to 2 in. of settlement could occur following a code-based seismic event. Based on the thickness of the non- liquefiable soil that mantles the site, we estimate the risk of ground manifestation of the seismically induced settlement is generally low. For design purposes, we recommend assuming differential seismic settlement will approach 50% of the calculated total seismic settlement over the length of the building. The 2015 National Earthquake Hazards Reduction Program (NEHRP) document titled "Recommended Seismic Provisions for New Buildings and Other Structures" provides guidance for acceptable limits of seismic differential settlement for different types of structures and different risk categories. In our opinion and based on Table 12.13-3 of 2015 NEHRP, 0.5 to 1 in. of seismic differential settlement over the length of the building is acceptable and consistent with current standards of practice for a life-safety performance G R U 10 • level. However, the structural engineer should determine if the structure can accommodate the estimated total and differential seismic settlement. Tying the foundations together with a network of grade beams could be considered to help reduce the potential adverse effects associated with differential vertical movement. The grade beams should be designed in accordance with the guidelines presented in the 2015 NEHRP document. All footings should be established in the medium-stiff, native soil that mantles the site. The base of all new footings should be established at a minimum depth of 18 in. below the lowest adjacent finished grade. The footing width should not be less than 24 in. for isolated column footings and 18 in. for wall footings. Due to the variable subgrade conditions, we recommend all foundations be underlain by a minimum 6-in. thickness of compacted crushed rock. Relatively clean, 3/4-in.-minus crushed rock is suitable for this purpose. Excavations for all foundations should be made with a smooth-edge bucket, and all footing subgrades should be observed by a member of GRI's geotechnical engineering staff. Soft or otherwise unsuitable material encountered at foundation subgrade level should be overexcavated and backfilled with granular structural fill. Local areas of softer subgrade may require deeper overexcavation and should be evaluated by a member of GRI's geotechnical engineering staff. Footings established in accordance with these criteria can be designed on the basis of an allowable soil bearing pressure of 2,500 psf. This value applies to the total of dead load and/or frequently applied live loads and can be increased by one-third for the total of all loads: dead, live, and wind or seismic. We estimate the total static settlement of spread and wall footings designed in accordance with the recommendations presented above will be less than 1 in. for footings supporting column and wall loads of up to 200 kips and 4 kips/ft, respectively. Differential static settlements between adjacent, comparably loaded footings should be less than half the total settlement. Horizontal shear forces can be resisted partially or completely by frictional forces developed between the base of the footings and the underlying soil and by soil passive resistance. The total frictional resistance between the footing and the soil is the normal force times the coefficient of friction between the soil and the base of the footing. We recommend an ultimate value of 0.35 for the coefficient of friction for footings cast on granular material. The normal force is the sum of the vertical forces (dead load plus real live load). If additional lateral resistance is required, passive earth pressures against embedded footings can be computed on the basis of an equivalent fluid having a unit weight of 250 pcf. This design passive earth pressure would be applicable only if the footing is cast neat against undisturbed soil or if backfill for the footings is placed as granular structural fill and assumes up to 1/2 in. of lateral movement of the structure will occur in order for the soil to develop this resistance. This value also assumes the ground surface in front of the foundation is horizontal, i.e., does not slope downward away from the toe of the footing. Subdrainage/Floor Support To provide a capillary break and reduce the risk of damp floors, slab-on-grade floors established at or above adjacent final site grades should be underlain by a minimum 8 in. of free-draining, clean, angular rock. This material should consist of angular rock such as 11/2- to 3/4-in. crushed rock with less than 2% passing the No. 200 sieve (washed analysis) and should be placed in one lift and compacted to at least 95% of the maximum dry density (ASTM D698) or until well keyed. To improve workability, the drain rock can be capped with a 2-in.-thick layer of compacted, 3/4-in.-minus crushed rock. In areas where floor coverings will be provided or moisture-sensitive materials stored, it would be appropriate to also install a G RD 11 vapor-retarding membrane. The membrane should be installed as recommended by the manufacturer. In addition, a foundation drain should be installed around the building perimeter to collect water that could potentially infiltrate beneath the foundations and should discharge to an approved storm drain. We anticipate the finished floor elevation for the majority of the partially embedded lower level will be established below final site grades. Unless the partially embedded lower level is designed to be watertight and resist hydrostatic pressures, subdrainage should be provided for the portion of the structure established below final site grades. A subdrainage system will reduce hydrostatic pressure and the risk of groundwater entering through the embedded wall and floor slabs. Typical subdrainage details for embedded structures are shown on Figure 3. The figure shows peripheral subdrains to drain embedded walls and an interior granular drainage blanket beneath the concrete floor slab, which is drained by a system of subslab drainage pipes. All perched groundwater collected should be drained by gravity or pumped from sumps into the stormwater disposal facility. If the water is pumped, an emergency power supply should be included to prevent flooding due to power loss. In our opinion, it is appropriate to assume a coefficient of subgrade reaction, k, of 175 pci to characterize the subgrade support for point loading with 8 in. of compacted crushed rock beneath the floor slab. Retaining Walls General. We anticipate construction of the partially embedded lower level will require embedded walls with a maximum height of 10 ft. We anticipate the walls will be cast-in-place concrete. Foundation design and subgrade preparation should conform to the recommendations provided above for spread footings. Lateral Earth Pressures. Design lateral earth pressures for retaining walls depend on the type of construction, i.e., the ability of the wall to yield. Possible conditions are 1) a wall that is laterally supported at its base and top and therefore unable to yield to the active state and 2) a retaining wall, such as a typical cantilever or gravity wall, that yields to the active state by tilting about its base. A conventional basement wall and cantilever retaining wall are examples of non-yielding and yielding walls, respectively. For completely drained, horizontal backfill, yielding and non-yielding walls may be designed on the basis of equivalent fluid unit weights of 35 and 50 pcf, respectively. To account for seismic loading, the earth pressure should be increased by 10 and 18 pcf for yielding and non-yielding walls, respectively. This results in a triangular distribution with the resultant acting at 1/3H up from the base of the wall, where H is the height of the wall in feet. Additional lateral loading due to surcharge loads can be evaluated using the criteria shown on Figure 4. The lateral earth pressure criteria presented above are appropriate if the retaining walls are fully drained. We recommend installation of a permanent drainage system behind all the retaining walls. The drainage system can either consist of a drainage blanket of rock or continuous drainage panels between the retained soil/backfill and the face of the wall. The drainage blanket should have a minimum width of 12 in. and consist of crushed drain rock that contains less than 2% fines content (washed analysis). A typical drainage system for embedded walls is shown on Figure 3. The drainage blanket or drainage panels should extend to the base of the wall, where water should be collected in a perforated pipe and discharged to a suitable outlet, such as a sump or approved storm drain. In addition, the wall design should include positive drainage measures to prevent ponding of surface water behind the top of the wall. CI R 0 12 Overcompaction of backfill behind walls should be avoided. Heavy compactors and large pieces of construction equipment should not operate within 5 ft of any retaining wall to avoid the buildup of excessive lateral earth pressures. Compaction close to the walls should be accomplished with hand-operated vibratory-plate compactors. Overcompaction of backfill could significantly increase lateral earth pressures behind walls and cause damage to cast-in-place concrete retaining walls. Pavement Design We anticipate the bus loop pavement will be subjected to bus, automobile, and light truck traffic and the parking areas will be subjected primarily to automobile and light truck traffic, with occasional heavy truck traffic. We anticipate the majority of the site will be paved with AC pavement; however, areas subjected to repeated heavy truck traffic, such as trash-enclosure and service areas, may be paved with PCC pavement. Traffic estimates for the roadways and parking areas are presently unknown. Based on our experience with similar projects and subgrade soil conditions, we recommend the following pavement sections. RECOMMENDED PAVEMENT SECTIONS CRB AC Thickness,in. Thickness,in. Areas Subject to School-Bus Traffic(Bus 14 5 Loop) Areas Subject to Primarily Automobile 12 4 Traffic(Service Road&Vehicle Drive Lanes) Areas Subject to Automobile Parking 8 3 (Parking Stalls) CRB PCC Thickness,in. Thickness,in. Areas Subject to Repeated Heavy Truck 6 6 Traffic(Trash-Enclosure&Service Areas) The recommended pavement sections should be considered minimum thicknesses and underlain by a woven geotextile fabric. It should be assumed some maintenance will be required over the life of the pavement (15 to 20 years). The recommended pavement sections are based on the assumption pavement construction will be accomplished during the dry season and after construction of the building has been completed. If wet-weather pavement construction is considered, it will likely be necessary to increase the thickness of CRB to support construction equipment and protect the subgrade from disturbance. The indicated sections are not intended to support extensive construction traffic, such as dump trucks and concrete trucks. Pavements subject to construction traffic may require repair. For the above-indicated sections, drainage is an essential aspect of pavement performance. We recommend all paved areas be provided positive drainage to remove surface water and water within the base course. This will be particularly important in cut sections or at low points within the paved areas, such as at catch basins. Effective methods to prevent saturation of the base course materials include providing weep holes in the sidewalls of catch basins, subdrains in conjunction with utility excavations, and separate trench drain systems. To ensure quality materials and construction practices, we recommend the pavement work conform to Oregon Department of Transportation standards. V R a 13 Prior to placing base course materials, all pavement areas should be proof rolled with a fully loaded, 10-cy dump truck. Any soft areas detected by the proof rolling should be overexcavated to firm ground and backfilled with compacted structural fill. Provided the pavement section is installed in accordance with the recommendations provided above, it is our opinion the site-access areas will support infrequent traffic by an emergency vehicle having a gross vehicle weight(GVW) of up to 75,000 lbs. For the purposes of this evaluation, "infrequent" can be defined as once a month or less. DESIGN REVIEW AND CONSTRUCTION SERVICES We welcome the opportunity to review and discuss construction plans and specifications for this project as they are being developed. In addition, GRI should be retained to review all geotechnical-related portions of the plans and specifications to evaluate whether they are in conformance with the recommendations provided in our report. To observe compliance with the intent of our recommendations, the design concepts, and the plans and specifications, we are of the opinion that all construction operations dealing with earthwork and foundations should be observed by a GRI representative. Our construction-phase services will allow for timely design changes if site conditions are encountered that are different from those described in our report. If we do not have the opportunity to confirm our interpretations, assumptions, and analyses during construction, we cannot be responsible for the application of our recommendations to subsurface conditions different from those described in this report. LIMITATIONS This report has been prepared to aid the architect and engineer in the design of this project. The scope is limited to the specific project and location described herein, and our description of the project represents our understanding of the significant aspects of the project relevant to the design and construction of the new foundations and floors. In the event any changes in the design and location of the project elements as outlined in this report are planned, we should be given the opportunity to review the changes and modify or reaffirm the conclusions and recommendations of this report in writing. The conclusions and recommendations submitted in this report are based on the data obtained from the explorations made at the locations indicated on Figure 2 and other sources of information discussed in this report. In the performance of subsurface investigations, specific information is obtained at specific locations at specific times. However, it is acknowledged that variations in soil conditions may exist between exploration locations. This report does not reflect any variations that may occur between these explorations. The nature and extent of variation may not become evident until construction. If during construction, subsurface conditions differ from those encountered in the explorations, we should be advised at once so that we can observe and review these conditions and reconsider our recommendations where necessary. Please contact the undersigned if you have any questions. ` 1 R D 14 Submitted for GRI, 4Ei)PROE45, Q<4 <, 1118281 9 9 luy N ✓AN 16, 10 SLEY Si* Renews 06/2018 Wesley Spang, Ph.D, PE, GE Nicholas M. Hatch, PE Principal Project Engineer This document has been submitted electronically. References Idriss, I.M., and Boulanger, R.W., 2008, Soil liquefaction during earthquakes: Earthquake Engineering Research Institute, EERI MNO-12. Idriss, I. M.,and Boulanger, R.W., 2014, CPT and SPT based liquefaction triggering procedures: Department of Civil & Environmental Engineering,College of Engineering, University of California at Davis, Report No. UCD/CGM-14/01. Madin, I.P.,1990, Earthquake-hazard geology maps of the Portland metropolitan area: Oregon Department of Geology and Mineral Studies,Open-File Report 90-02. Personius, S. F., Dart, R. L., Bradley, Lee-Ann, and Haller, K. M., 2003, Map and data for Quaternary faults and folds in Oregon: U.S.Geological Survey Open-File Report 03-095. U.S.Geological Survey(USGS),Unified hazard tool,Conterminous U.S.2014(v4.0x),accessed 5/30/17 from USGS website: https://earthquake.usgs.gov/hazards/interactive/. R p 15 a, • OFFICE COPY RECEIVED FE.h 10? Z0Z1 CITY OF TIGARD 13UILDING Q1VISION. APPENDIX A Field Explorations and Laboratory Testing APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING FIELD EXPLORATIONS Subsurface materials and conditions at the site were investigated between May 3 and May 5, 2017, with three borings, designated B-1 through B-3; three cone penetrometer test(CPT) soundings, designated CPT-1 through CPT-3; and one dilatometer (DMT) sounding, designated DMT-1. The approximate locations of the explorations completed for this investigation are shown on Figure 2. Logs of the borings, CPT probes, and DMT sounding are provided on Figures 1A through 9A. The field exploration work was coordinated and documented by an experienced member of GRI's geotechnical engineer staff, who maintained a log of the materials and conditions disclosed during the course of work. Borings Three borings, designated B-1 through B-3, were advanced to a depth of about 41.5 ft below existing site grades. The borings were completed with solid-stem auger drilling techniques using a trailer-mounted drill rig provided and operated by Dan J. Fischer Excavating, Inc., of Forest Grove, Oregon. Disturbed and undisturbed soil samples were obtained from the borings at 2.5-ft intervals of depth in the upper 15 ft and 5- to 10-ft intervals below this depth. Disturbed soil samples were obtained using a standard split-spoon sampler (SPT). The outside diameter of the SPT sampler was 2 in. Penetration tests were conducted by driving the sampler into the soil a distance of 18 in. using a 140-lb hammer dropped 30 in. The number of blows required to drive the SPT sampler the last 12 in. is known as the Standard Penetration Resistance, or SPT N-value. SPT N-values provide a measure of the relative density of granular soils and relative consistency of cohesive soils. Samples obtained from the borings were placed in airtight jars and returned to our laboratory for further classification and testing. In addition, relatively undisturbed samples were collected by pushing a 3-in.-outside- diameter (O.D.) Shelby tube into the undisturbed soil a maximum distance of 24 in. using the hydraulic ram of the drill rig. The soil exposed in the end of the Shelby tube was examined and classified in the field. After classification, the tube was sealed with rubber caps and returned to our laboratory for further examination and testing. Logs of the borings are provided on Figures 1A through 3A. Each log presents a descriptive summary of the various types of materials encountered in the boring and notes the depths at which the materials and/or characteristics of the materials change. To the right of the descriptive summary, the numbers and types of samples are indicated. Farther to the right, SPT N-values are shown graphically, along with the natural moisture contents, Torvane shear strength values, and percent passing the No. 200 sieve, where applicable. The terms and symbols used to describe the materials encountered in the borings are defined in Table 1A and the attached legend. Electric Cone Penetration Test Three electric CPT probe, designated CPT-1 through CPT-3, were advanced to depths of about 42 to 76 ft using a truck-mounted CPT rig provided and operated by Oregon Geotechnical Explorations, Inc., of Keizer, Oregon. During the CPT, a steel cone is forced vertically into the soil at a constant rate of penetration. The force required to cause penetration at a constant rate can be related to the bearing G R_D A-1 capacity of the soil immediately surrounding the point of the penetrometer cone. This force is measured and recorded every 8 in. In addition to the cone measurements, measurements are obtained of the magnitude of force required to force a friction sleeve, attached above the cone, through the soil. The force required to move the friction sleeve can be related to the undrained shear strength of fine-grained soils. The dimensionless ratio of sleeve friction to point bearing capacity provides an indicator of the type of soil penetrated. The cone-penetration resistance and sleeve friction can be used to evaluate the relative consistency of cohesionless and cohesive soils, respectively. In addition, a piezometer fitted between the cone and the sleeve measures changes in water pressure as the probe is advanced and can also be used to measure the depth of the top of the groundwater table. The probe was also operated using an accelerometer fitted to the probe, which allows measurement of the arrival time of shear waves from impulses generated at the ground surface. This allows calculation of shear-wave velocities for the surrounding soil profile. Logs of the electric CPT probes are provided on Figures 4A, 6A, and 7A, which present graphical summaries of the tip resistance, local (sleeve) friction, friction ratio, pore pressure, and soil behavior type (SBT) index. The types of soils encountered within the probe are shown graphically along the right side of the figure. The terms used to describe the soils encountered in the probe are defined in Table 2A. Shear- wave velocity measurements were recorded for the CPT-1 and CPT-3 probes and are shown on Figures 5A and 8A, respectively. Dilatometer Test One DMT sounding, designated DMT-1, was advanced to a depth of about 39 ft using a truck-mounted CPT rig provided and operated by Oregon Geotechnical Explorations, Inc., of Keizer, Oregon. DMT soundings provide additional geotechnical information to characterize the subsurface materials. The dilatometer test is performed by pushing a blade-shaped instrument into the soil. The blade is equipped with an expandable membrane on one side that is pressurized until the membrane moves horizontally into the surrounding soil. Readings of the pressures required to move the membrane to a point flush with the blade (Po— pressure) and 1.1 mm into the surrounding soil (Pi — pressure) are recorded. The test sequence was performed at 8-in. intervals to obtain a comprehensive soil profile. A material index (ID), horizontal stress index (KO), and dilatometer modulus (ED) are obtained directly from the dilatometer data. The constrained modulus (M) is then obtained from the dilatometer data. The dilatometer test results are summarized on Figure 9A. The results show the dilatometer pressure readings (Po, Pi) and three dilatometer- derived parameters: horizontal stress index (KD), material index (ID), and constrained modulus (M). The terms used to describe the materials encountered in the sounding are defined in Table 3A. LABORATORY TESTING General The samples obtained from the borings were examined in our laboratory, where the physical characteristics of the samples were noted and the field classifications modified where necessary. At the time of classification, the natural moisture content of each sample was determined. Additional testing included Torvane shear strength, dry unit weight, and grain size. A summary of the laboratory test results has been provided in Table 4A. The following sections describe the testing program in more detail. G R 0 A-2 Natural Moisture Content Natural moisture content determinations were made in conformance with ASTM D2216. The results are summarized on Figures 1A through 3A and in Table 4A. Torvane Shear Strength The approximate undrained shear strength of the fine-grained soils was determined using a Torvane shear device. The Torvane is a hand-held apparatus with vanes that are inserted into the soil. The torque required to fail the soil in shear around the vanes is measured using a calibrated spring. The results of the Torvane shear strength tests are summarized on Figures 1A and 2A. Undisturbed Unit Weight The unit weight, or density, of undisturbed soil samples was determined in the laboratory in conformance with ASTM D2937. The results are summarized on Figures 1 A and 2A and in Table 4A. Grain-Size Analysis Washed-Sieve Method. To assist in classification of the soils, samples of known dry weight were washed over a No. 200 sieve. The material retained on the sieve was oven-dried and weighed. The percentage of material passing the No. 200 sieve was then calculated. The results are summarized on Figures 1A through 3A and in Table 4A. .1R [ A-3 Table 1A GUIDELINES FOR CLASSIFICATION OF SOIL Description of Relative Density for Granular Soil Standard Penetration Resistance Relative Density (N-values),blows per ft very loose 0-4 loose 4- 10 medium dense 10-30 dense 30-50 very dense over 50 Description of Consistency for Fine-Grained(Cohesive)Soils Standard Penetration Torvane or Resistance(N-values), Undrained Shear Consistency blows per ft Strength,tsf very soft 0-2 less than 0.125 soft 2-4 0.125-0.25 medium stiff 4-8 0.25-0.50 stiff 8- 15 0.50- 1.0 very stiff 15-30 1.0-2.0 hard over 30 over 2.0 Grain-Size Classification Modifier for Subclassification Boulders: Primary Constituent Primary Constituent >12 in. SAND or GRAVEL SILT or CLAY Cobbles: Adjective Percentage of Other Material (by weight) 3- 12 in. trace: 5- 15 (sand,gravel) 5-15 (sand,gravel) Gravel: some: 15-30(sand,gravel) 15-30(sand,gravel) 1/4-3/4 in. (fine) sandy'gravelly:ravel I 30-50(sand,gravel) 30-50(sand,gravel) 3/4-3 in. (coarse) Sand: trace: <5 (silt,clay) No. 200- No.40 sieve(fine) Relationship of clay and No.40-No. 10 sieve(medium) some: 5 12 (silt, clay) silt determined by No. 10- No.4 sieve(coarse) silty, clayey: 12-50(silt, clay) plasticity index test Silt/Clay: pass No.200 sieve W �r Table 2A: CONE PENETRATION TEST(CPT) CORRELATIONS COHESIVE SOILS Cone-Tip Resistance,tsf Consistency <5 Very Soft 5 to 15 Soft to Medium Stiff 15 to 30 Stiff 30 to 60 Very Stiff >60 Hard COHESIONLESS SOILS Cone-Tip Resistance,tsf Relative Density <20 Very Loose 20 to 40 Loose 40 to 120 Medium 120 to 200 Dense >200 Very Dense Reference Kulhawy,F.H.,and Mayne,P.W., 1990,Manual on estimating soil properties for foundation design: Electric Power Research Institute,EL-6800. Table 3A: SOIL CHARACTERIZATION BASED ON MARCHETTI FLAT-PLATE DILATOMETER TEST Description of Consistency for Fine-Grained (Cohesive) Soils Soil Type"' CH, CL ML, MH DMT Constrained Modulus(MDMT),tsf Consistency ID 2'< 0.6 0.6 <Io(2'< 1.8 Very Soft 0-30 0- 50 Soft 30-60 50- 100 Medium Stiff 60- 100 100-200 Stiff 100- 175 200- 375 Very Stiff 175 + 375 + Description of Relative Density for Granular Soils Soil Type' SM, SC SP, SW DMT Constrained Modulus(MDMT),tsf Relative Density 1.8 <I D(2)< 3.3 3.3 <I p 2) Very Loose 0-75 0- 100 Loose 75 - 150 100-200 Medium Dense 150-300 200-425 Dense 300- 550 425 -850 Very Dense 550 + 850 + 1) Unified Soil Classification System 2) ID = Material Index Table 4A SUMMARY OF LABORATORY RESULTS Sample Information Atterberg Limits Moisture Dry Unit Liquid Plasticity Fines Location Sample Depth,ft Elevation,ft Content, % Weight,pcf Limit, % Index, % Content, % Soil Type B-1 S-1 2.5 - 24 - - - - Sandy SILT S-2 5.3 - 31 - - - 62 Sandy SILT S-2 6.3 - 31 90 - - - Sandy SILT S-3 6.8 - 32 - - - 45 Sandy SILT S-4 10.3 - 28 - - - 24 Silty SAND S-4 11.1 - 25 96 - - - Silty SAND S-5 11.7 - 26 - - - - Silty SAND S-6 15.0 - 29 - - - 18 Silty SAND S-7 20.0 - 33 - - - - Silty SAND S-8 25.0 - 33 - - - - Silty SAND S-9 30.0 - 30 - - - - Silty SAND S-10 35.0 - 24 - - - 36 Silty SAND S-11 40.0 - 35 - - - - Silty SAND B-2 S-1 2.8 - 31 - - - 64 Sandy SILT S-1 3.5 - 37 83 - - - Sandy SILT S-2 4.3 - 29 - - - - Sandy SILT S-3 7.5 - 28 - - - 22 Silty SAND S-4 10.0 - 31 - - - - Silty SAND S-5 12.5 - 31 - - - - Silty SAND S-6 15.0 - 30 - - - - Silty SAND S-7 20.0 - 29 - - - 39 Silty SAND S-8 25.0 - 27 - - - - SAND S-9 30.0 - 29 - - - - SAND S-10 40.0 - 31 - - - - SAND B-3 S-1 2.8 - 29 92 - - - Silty SAND S-1 3.7 - 27 - - - 47 Silty SAND S-2 4.5 - 29 - - - - Sandy SILT S-4 10.0 - 39 - - - - Sandy SILT S-4 11.0 - 24 - - - 20 Silty SAND S-5 12.5 - 30 - - - 56 Sandy SILT S-6 15.0 - 30 - - - - Silty SAND S-7 20.0 - 32 - - - - Silty SAND S-8 25.0 - 28 - - - 29 Silty SAND S-9 30.0 - 30 - - - - Silty SAND S-9 30.5 - 29 - - - - Silty SAND S-10 40.0 - 26 - - - 27 Silty SAND ci; 1II Page 1 of 1 BORING AND TEST PIT LOG LEGEND SOIL SYMBOLS SAMPLER SYMBOLS Symbol Typical Description Symbol Sampler Description .,A 1/4.. T 2.0-in. O.D. split-spoon sampler and Standard LANDSCAPE MATERIALS 1 Penetration Test with recovery (ASTM D1586) :::• FILL Shelby tube sampler with recovery (ASTM D1587) o 3o GRAVEL; clean to some silt, clay, and sand 3.0 in. O.D. split spoon sampler with recovery (ASTM D3550) ,.Ba Sandy GRAVEL; clean to some silt and clay Grab Sample 111 Silty GRAVEL; up to some clay and sand Rock core sample interval a 14 Clayey GRAVEL; up to some silt and sand Sonic core sample interval ` •``' SAND; clean to some silt, clay, and gravel t Geoprobe sample interval s Gravelly SAND; clean to some silt and clay INSTALLATION SYMBOLS M1 'y Silty SAND; up to some clay and gravel Symbol Symbol Description •t?` Clayey SAND; up to some silt and gravel in Flush-mount monument set in concrete SILT; up to some clay, sand, and gravel ® Concrete,well casing shown where applicable OHGravelly SILT; up to some clay and sand j'j Bpent pl nit eseal, well casing shown where Sandy SILT; up to some clay and gravel Filter pack, machine-slotted well casing shown •— • where applicable DP Clayey SILT; up to some sand and gravel 11 Grout, vibrating-wire transducer cable shown where applicable / CLAY; up to some silt, sand, and gravel • Vibrating-wire pressure transducer _4 Gravelly CLAY; up to some silt and sand I 1-in.-diameter solid PVC Sandy CLAY; up to some silt and gravel I 1-in.-diameter hand-slotted PVC �A A Silty CLAY; up to some sand and gravel Grout, inclinometer casing shown where applicable PEAT FIELD MEASUREMENTS BEDROCK SYMBOLS Symbol Typical Description Symbol Typical Description a Groundwater level during drilling and date measured +++ BASALT Y. Groundwater level after drilling and date measured w MUDSTONE Rock core recovery(%) W =� SILTSTONE / Rock quality designation (RQD, %) O _ o SANDSTONE a 0 W SURFACE MATERIAL SYMBOLS W Symbol Typical Description 8 o IIIa Asphalt concrete PAVEMENT IIPortland cement concrete PAVEMENT a o�t z ,Qa Crushed rock BASE COURSE 0 0 �rrrrrr 1 • OFFICE COPY RECEIVED FEB10 2O2 CITY OF TIGARD BUILDING DIVISION APPENDIX B Twality Middle School Project Subsurface Logs and Laboratory Results ta. Table 1A: GUIDELINES FOR CLASSIFICATION OF SOIL Description of Relative Density for Granular Soil Standard Penetration Resistance Relative Density (N-values),blows per ft Very Loose 0-4 Loose 4- 10 Medium Dense 10-30 Dense 30-50 Very Dense over 50 Description of Consistency for Fine-Grained(Cohesive)Soils Standard Penetration Torvane or Resistance(N-values), Undrained Shear Consistency blows per ft Strength,tsf Very Soft 0-2 less than 0.125 Soft 2-4 0.125-0.25 Medium Stiff 4-8 0.25-0.50 Stiff 8- 15 0.50- 1.0 Very Stiff 15-30 1.0-2.0 Hard over 30 over 2.0 Grain-Size Classification Modifier for Subclassification Boulders: Primary Constituent Primary Constituent >12 in. SAND or GRAVEL SILT or CLAY Cobbles: Adjective Percentage of Other Material (by weight) 3- 12 in. trace: 5- 15 (sand, gravel) 5- 15 (sand, gravel) Gravel: some: 15-30(sand,gravel) 15-30 (sand, gravel) 1/4-3/4 in. (fine) sandy,gravelly: 30-50(sand,gravel) 30-50(sand,gravel) 3/4- 3 in. (coarse) Sand: trace: <5 (silt, clay) No. 200-No.40 sieve(fine) Relationship of clay and No.40- No. 10 sieve(medium) some: 5 12 (silt, clay) silt determined by No. 10-No.4 sieve(coarse) silty, clayey: 12-50(silt,clay) plasticity index test Silt/Clay: pass No. 200 sieve GRU • Table 2A: CONE PENETRATION TEST(CPT)CORRELATIONS COHESIVE SOILS Cone Tip Resistance,tsf Consistency <5 Very Soft 5 to 15 Soft to Medium Stiff 15 to 30 Stiff 30 to 60 Very Stiff >60 Hard COHESIONLESS SOILS Cone Tip Resistance,tsf Relative Density <20 Very Loose 20 to 40 Loose 40 to 120 Medium 120 to 200 Dense >200 Very Dense Reference: Kulhawy, F.H. and Mayne, P.W., 1990, Manual on Estimating Soil Properties for Foundation Design, Electric Power Research Institute,EL-6800 Goa it � un Table 3A: SOIL CHARACTERIZATION BASED ON MARCHETTI FLAT PLATE DILATOMETER TEST Description of Consistency for Fine-Grained(Cohesive) Soils Soil Type" CH, CL ML, MH DMT Constrained Modulus(Mow),tsf Consistency ID2'< 0.6 0.6 <Ip2'< 1.8 Very Soft 0-30 0-50 Soft 30-60 50- 100 Medium Stiff 60- 100 100-200 Stiff 100- 175 200- 375 Very Stiff 175 + 375 + Description of Relative Density for Granular Soils Soil Type" SM, SC SP, SW DMT Constrained Modulus(MDMT),tsf Relative Density 1.8 <ID 2 < 3.3 3.3 <Ipc2' Very Loose 0-75 0- 100 Loose 75 - 150 100-200 Medium Dense 150- 300 200-425 Dense 300- 550 425 -850 Very Dense 550 + 850 + 1) Unified Soil Classification System 2) ID = Material Index GR D Table 4A SUMMARY OF LABORATORY RESULTS Sample Information Atterberg limits Moisture Dry Unit liquid Plasticity Fines Location Sample Depth,ft Elevation,ft Content, % Weight, pcf limit, % Index, % Content, % Soil Type B-1 S-1 2.8 - 28 -- - -- 57 Sandy SILT S-1 3.7 - 30 91 -- - - Sandy SILT S-2 4.5 - 32 - - - - Sandy SILT S-3 7.5 - 28 - - -- 29 Silty SAND S-4 10.0 - 20 -- -- -- 28 Silty SAND S-5 12.5 - 33 - - - - Silty SAND S-5 13.0 - 17 - - - - Silty SAND S-6 15.0 - 19 -- - -- 28 Silty SAND S-7 20.0 - 25 - -- -- -- Silty SAND S-8 25.0 - 21 - -- - - Silty SAND S-9 30.0 - 30 - - - 19 Silty SAND S-10 35.0 - 27 - - - - Silty SAND S-10 36.0 - 29 - - - - Silty SAND B-2 S-1 2.5 - 24 -- - - 51 Sandy SILT S-2 5.7 -- 30 91 -- - 57 Sandy SILT S-3 6.1 - 29 - - - - Sandy SILT S-4 10.0 -- 27 - - - 67 Sandy SILT S-5 12.8 - 27 - - - 57 Sandy SILT S-5 14.2 - 28 94 - - - Sandy SILT S-6 14.5 -- 25 -- - -- - Sandy SILT S-7 20.0 -- 32 -- -- - - Sandy SILT S-8 25.0 -- 31 - - - -- Clayey SILT B-3 S-1 2.5 -- 24 - - - -- Silty SAND S-2 5.0 - 29 - - - 47 Silty SAND S-3 7.5 - 27 - - - - Silty SAND S-4 10.0 - 18 - - - 18 Silty SAND S-5 12.5 -- 18 -- - - - Silty SAND S-6 15.0 -- 27 -- -- - -- Silty SAND S-7 20.0 - 31 - - - - Silty SAND S-8 25.0 - 29 - - - 25 Silty SAND S-9 30.0 - 33 - - - - Silty SAND S-10 35.0 - 27 - - - 33 Silty SAND S-11 40.0 - 27 - - - - Silty SAND 5-11 41.0 - 32 - - - - Silty SAND 5-12 50.0 - 30 - - - - Clayey SILT G RHPage 1 of 1 BORING AND TEST PIT LOG LEGEND SOIL SYMBOLS SAMPLER SYMBOLS Symbol Typical Description Symbol Sampler Description : I 2.0-in. O.D. split-spoon sampler and Standard LANDSCAPE MATERIALS Penetration Test with recovery (ASTM D1586) ""''" I Shelby tube sampler with recovery � FILL :tow.. (ASTM D1587) ;p l GRAVEL; clean to some silt, clay, and sand 3.0 in. O.D. split spoon sampler with recovery ° (ASTM D3550) 0'Wl °.C° Sandy GRAVEL;clean to some silt and clay Grab Sample lilSilty GRAVEL; up to some clay and sand 11 Rock core sample interval Clayey GRAVEL; up to some silt and sand Sonic core sample interval SAND; clean to some silt, clay,and gravel Geoprobe sample interval dti;. Gravelly SAND; clean to some silt and clay INSTALLATION SYMBOLS Silty SAND; up to some clay and gravel Symbol Symbol Description XIClayey SAND; up to some silt and gravel I Flush mount monument set in concrete SILT; up to some clay, sand, and gravel Concrete,well casing shown where applicable iinGravelly SILT; up to some clay and sand j'j Ben o it eseal, well casing shown where Sandy SILT; up to some clay and gravel .:�.: Filter pack, machine-slotted well casing shown • where applicable HClayey SILT; up to some sand and gravel Grout, vibrating-wire transducer cable shown �' c where applicable //j CLAY; up to some silt, sand, and gravel • Vibrating-wire pressure transducer fGravelly CLAY; up to some silt and sand I 1-in.-diameter solid PVC Sandy CLAY; up to some silt and gravel 1 1-in.-diameter hand-slotted PVC PP Silty CLAY; up to some sand and gravel Grout, inclinometer casing shown where applicable VIA? PEAT �^^�'�` FIELD MEASUREMENTS BEDROCK SYMBOLS Symbol Typical Description Symbol Typical Description V Groundwater level during drilling and date N. measured +++ BASALT t Groundwater level after drilling and date +++ measured wMUDSTONE Rock core recovery(%) gO. _ _� SILTSTONE Rock quality designation (RQD, %) SANDSTONE a z SURFACE MATERIAL SYMBOLS W W Symbol Typical Description 0 0 _ ■ Asphalt concrete PAVEMENT co Portland cement concrete PAVEMENT 0z ovi. z °p° Crushed rock BASE COURSE E 0 03 441 } OFFICE COPY REGEMZD FEB 10 2021 CITY OF TIGARD BUILDING DIVISION APPENDIX C Site-Specific Seismic-Hazard Evaluation APPENDIX C SITE-SPECIFIC SEISMIC-HAZARD STUDY GENERAL GRI completed a site-specific seismic-hazard study for the proposed new Templeton Elementary School in Tigard, Oregon. The purpose of our study was to evaluate the potential seismic hazards associated with regional and local seismicity. The site-specific seismic-hazard evaluation is intended to meet the requirements of the 2014 Oregon Structural Specialty Code (OSSC), which is based on the 2012 International Building Code (IBC). Seismic design in accordance with the 2012 IBC is based on the American Society of Civil Engineers (ASCE) 7-10 document, titled "Minimum Design Loads for Buildings and Other Structures." Our work was based on the potential for regional and local seismic activity, as described in the existing scientific literature, and the subsurface conditions at the site, as disclosed by the subsurface explorations completed for this project. Specifically, our work included the following tasks: 1) A detailed review of available literature, including published papers, maps, open-file reports, seismic histories and catalogs, works in progress, and other sources of information regarding the tectonic setting, regional and local geology, and historical seismic activity that might have a significant effect on the site. 2) Compilation and evaluation of subsurface data collected at and in the vicinity of the site, including classification and laboratory analyses of soil samples, and review of shear-wave velocity surveys completed at the site. This information was used to prepare a generalized subsurface profile for the site. 3) Identification of the potential seismic events (earthquakes) appropriate for the site and characterization of those events in terms of a generalized design event. 4) Office studies based on the generalized subsurface profile and the generalized design earthquake resulting in conclusions and recommendations concerning: a) specific seismic events that might have a significant effect on the site, b) the potential for seismic energy amplification and liquefaction or soil-strength loss at the site, and c) site-specific acceleration response spectra for design of the proposed structure. This appendix describes the work accomplished and summarizes our conclusions and recommendations. Geologic Setting On a regional scale, the site is located at the northern end of the Willamette Valley, a broad, gently deformed, north-south-trending topographic feature separating the Coast Range to the west from the Cascade Mountains to the east. The site is located approximately 74 km inland from the Cascadia Subduction Zone (CSZ), an active plate boundary along which remnants of the Farallon plate (the Gorda, Juan de Fuca, and Explorer plates) are being subducted beneath the western edge of the North American GR C-1 leastissammissmoismmommg plate. The subduction zone is a broad, eastward-dipping zone of contact between the upper portion of the subducting slabs of the Gorda,Juan de Fuca, and Explorer plates and the overriding North American plate, as shown on the Tectonic Setting Summary, Figure 1 C. On a local scale, the site is located in the Tualatin Basin, a large, well-defined, southeast-trending structural basin bounded by high-angle, northwest-trending, right-lateral, strike-slip faults considered to be seismogenic. The geologic units in the area are shown on the Regional Geologic Map, Figure 2C. The distribution of nearby Quaternary faults is shown on the Local Fault Map, Figure 3C. Information regarding the continuity and potential activity of these faults is lacking due largely to the scale at which geologic mapping in the area has been conducted and the presence of thick, relatively young, basin-filling sediments that obscure underlying structural features. Other faults may be present within the basin, but clear stratigraphic and/or geophysical evidence regarding their location and extent is not presently available. Additional discussion regarding crustal faults is provided in the Local Crustal Event section below. Because of the proximity of the site to the CSZ and its location within the Tualatin Basin, three distinctly different sources of seismic activity contribute to the potential for the occurrence of damaging earthquakes. Each of these sources is generally considered to be capable of producing damaging earthquakes. Two of these sources are associated with the deep-seated tectonic activity related to the subduction zone; the third is associated with movement on the local, relatively shallow structures within and adjacent to the Tualatin Basin. Subsurface and Geologic Conditions. Published geologic mapping indicates the site is mantled with Missoula flood deposits, locally referred to in the project area as the Willamette Silt Formation (Madin, 1990). In general, Willamette Silt is composed of unconsolidated beds and lenses of silt and sand. Stratification within this formation commonly consists of 4-to 6-in.-thick beds, although in some areas the silt and sand are massive and the bedding is indistinct or nonexistent. Based on the explorations completed for this project, the Willamette Silt is underlain by Columbia River Basalt at depths of about 41.5 to 75 ft at the site. Seismicity General. The geologic and seismologic information available for identifying the potential seismicity at the site is incomplete, and large uncertainties are associated with estimates of the probable magnitude, location, and frequency of occurrence of earthquakes that might affect the site. The available information indicates the potential seismic sources that may affect the site can be grouped into three independent categories: subduction zone events related to sudden slip between the upper surface of the Juan de Fuca plate and the lower surface of the North American plate, subcrustal events related to deformation and volume changes within the subducted mass of the Juan de Fuca plate, and local crustal events associated with movement on shallow, local faults within and adjacent to the Tualatin Basin. Based on our review of currently available information, we have developed generalized design earthquakes for each of these categories. The design earthquakes are characterized by three important properties: size, location relative to the subject site, and the peak horizontal bedrock accelerations produced by the event. In this study, earthquake size is expressed by the moment magnitude (Mw); location is expressed as the closest distance to the fault rupture, measured in kilometers; and peak horizontal bedrock accelerations are expressed in units of gravity(1 g = 32.2 ft/sec2 = 981 cm/sect). G R a C-2 Subduction Zone Event. The last interplate earthquake on the CSZ occurred in January 1700. Geological studies show that great megathrust earthquakes have occurred repeatedly in the past 7,000 years (Atwater et al., 1995; Clague, 1997; Goldfinger et al., 2003; and Kelsey et al., 2005), and geodetic studies (Hyndman and Wang, 1995; Savage et al., 2000) indicate rate of strain accumulation consistent with the assumption that the CSZ is locked beneath offshore northern California, Oregon, Washington, and southern British Columbia (Fluck et al., 1997; Wang et al., 2001). Numerous geological and geophysical studies suggest the CSZ may be segmented (Hughes and Carr, 1980; Weaver and Michaelson, 1985; Guffanti and Weaver, 1988; Goldfinger, 1994; Kelsey and Bockheim, 1994; Mitchell et al., 1994; Personius, 1995; Nelson and Personius, 1996; Witter, 1999), but the most recent studies suggest that for the last great earthquake in 1700, most of the subduction zone ruptured in a single Mw 9.0 earthquake (Satake et al., 1996; Atwater and Hemphill-Haley, 1997; Clague et al., 2000). Published estimates of the probable maximum size of subduction zone events range from moment magnitude Mw 8.3 to >9.0. Numerous detailed studies of coastal subsidence, tsunamis, and turbidites yield a wide range of recurrence intervals, but the most complete records (>4,000 years) indicate average intervals of 350 to 600 years between great earthquakes on the CSZ (Adams, 1990; Atwater and Hemphill-Haley, 1997; Witter, 1999; Clague et al., 2000; Kelsey et al., 2002; Kelsey et al., 2005; Witter et al., 2003). Tsunami inundation in buried marshes along the Washington and Oregon coast and stratigraphic evidence from the Cascadia margin support these recurrence intervals (Kelsey et al., 2005; Goldfinger et al., 2003). The U.S. Geological Survey (USGS) probabilistic analysis assumes four potential locations for the location of the eastern edge of the earthquake rupture zone, shown on Figure 4C. The 2008 USGS mapping effort indicates three rupture scenarios are assumed to represent these interface events: 1) Mw 9.0±0.2 events that rupture the entire CSZ every 500 years, 2) Mw 8.3 to 8.7 events with rupture zones that occur on segments of the CSZ and occur over the entire length of the CSZ during a period of about 500 years, and 3) Mw 8.0 to 8.2 events that rupture only segments of the CSZ every 500 years (Petersen et al., 2008). The assumed distribution of earthquakes is shown on the Assumed Magnitude-Frequency Distribution, Figure 5C. This distribution assumes the larger Mw 9.0 earthquakes likely occur more often than each of the smaller segmented ruptures, as also indicated by the USGS deaggregation for the site. Therefore, for our deterministic analysis, we have chosen to represent the subduction zone event by a design earthquake of Mw 9.0 at a focal depth of 30 km and rupture distance of 74 km. This corresponds to a sudden rupture of the whole length of the Juan de Fuca-North American plate interface with an assumed rupture zone due west of the site. Based on an average of the attenuation relationships published by Atkinson and Macias (2009), Zhao et al. (2006), and Abrahamson et al. (2015), a subduction zone earthquake of this size and location would result in a peak horizontal bedrock acceleration of approximately 0.24 g at the site. Subcrustal Event. There is no historical record of significant subcrustal, intraslab earthquakes in Oregon. Although both the Puget Sound and northern California region have experienced many of these earthquakes in historical times, Wong (2005) hypothesizes that due to subduction zone geometry, geophysical conditions, and local geology, Oregon may not be subject to intraslab earthquakes. In the Puget Sound area, these moderate to large earthquakes are deep (40 to 60 km) and over 200 km from the deformation front of the subduction zone. Offshore along the northern California coast, the earthquakes are shallower (up to 40 km) and located along the deformation front. Estimates of the probable size, location, and frequency of subcrustal events in Oregon are generally based on comparisons of the CSZ with active convergent plate margins in other parts of the world and on the historical seismic record for the region surrounding Puget Sound, where significant events known to have occurred within the subducting D C-3 Juan de Fuca plate have been recorded. Published estimates of the probable maximum size of these events range from moment magnitude Mw 7.0 to 7.5. The 1949, 1965, and 2001 documented subcrustal earthquakes in the Puget Sound area correspond to Mw 7.1, 6.5, and 6.8, respectively. Published information regarding the location and geometry of the subducting zone indicates a focal depth of 50 km is probable (Weaver and Shedlock, 1989). We have chosen to represent the subcrustal event by a design earthquake of magnitude Mw 7.0 at a focal depth of 50 km and a rupture distance of 63 km. Based on the attenuation relationships published by Youngs et al. (1997) and Abrahamson et al. (2015), a subcrustal earthquake of this size and location would result in a peak horizontal bedrock acceleration of approximately 0.17 g at the site. Local Crustal Event. Sudden crustal movements along relatively shallow, local faults in the Portland area, although rare, have been responsible for local crustal earthquakes. The precise relationship between specific earthquakes and individual faults is not well understood since few of the faults in the area are expressed at the ground surface and the foci of the observed earthquakes have not been located with precision. The history of local seismic activity is commonly used as a basis for determining the size and frequency to be expected of local crustal events. Although the historical record of local earthquakes is relatively short (the earliest reported seismic event in the area occurred in 1920), it can serve as a guide for estimating the potential for seismic activity in the area. Based on fault mapping conducted by the USGS (Personius et al., 2003), the inferred location of the Canby-Mollala Fault underlies the site. However, the USGS does not consider the Canby-Mollala Fault to be an active, contributing source in their Probabilistic Seismic Hazard Analysis (PSHA). Based on our review of the USGS deaggregations for the site (U.S. Geological Survey, 2014), the Portland Hills Fault is the closest crustal fault contributing to the overall seismic hazard at the site. The inferred location of the Portland Hills Fault is approximately 12 km from the site, and the fault has a characteristic earthquake magnitude of Mw = 7. A crustal earthquake of this size would result in a peak horizontal bedrock acceleration of approximately 0.42 g at the site based on an average of the next generation attenuation (NGA) ground-motion relations published by Boore et al. (2014), Campbell and Bozorgnia (2014), and Chiou and Youngs (2014). Summary of Deterministic Earthquake Parameters In summary, three distinctly different types of earthquakes affect seismicity in the project area. Deterministic evaluation of the earthquake sources using recently published attenuation ground-motion relations provides estimates of ground response for each individual earthquake type. Unlike probabilistic estimates, these deterministic estimates are not associated with a relative hazard level or probability of occurrence and simply provide an estimate of the ground-motion parameters for each type of fault at a given distance from the site. The basic parameters of each type of earthquake are as follows: Average Earthquake Attenuation Relationships Rupture Focal Peak Bedrock Peak Bedrock Source for Deterministic Spectra Magnitude,M. Distance,km Depth,km Acceleration,g Acceleration,g Subduction Zone Atkinson and Macias,2009 9.0 74.0 30 0.18 Zhao et al.,2006 9.0 74.0 30 0.23 0.24 Abrahamson et al.,2015 9.0 74.0 30 0.30 Subcrustal Youngs et al., 1997 7.0 63.0 50 0.10 0.17 GRU C-4 Average Earthquake Attenuation Relationships Rupture Focal Peak Bedrock Peak Bedrock Source for Deterministic Spectra Magnitude,M. Distance,km Depth,km Acceleration,g Acceleration,g Abrahamson et al.,2015 7.0 63.0 50 0.24 Local Crustal Campbell and Bozorgnia,2014 7.0 12.0 NA 0.48 Chiou and Youngs,2014 7.0 12.0 NA 0.39 0.42 Boore et al. (2014) 7.0 12.0 NA 0.40 Probabilistic Considerations The probability of an earthquake of a specific magnitude occurring at a given location is commonly expressed by its return period, i.e., the average length of time between successive occurrences of an earthquake of that size or larger at that location. The return period of a design earthquake is calculated once a project design life and some measure of the acceptable risk that the design earthquake might occur or be exceeded are specified. These expected earthquake recurrences are expressed as a probability of exceedance during a given time period or design life. Historically, building codes have adopted an acceptable risk level by identifying ground acceleration values that meet or exceed a 10% probability of exceedance in 50 years, which corresponds to an earthquake with an expected recurrence interval of 475 years. Previous versions of the IBC developed response spectra based on ground motions associated with the Maximum Considered Earthquake (MCE), which is generally defined as a probabilistic earthquake with a 2% probability of exceedance in 50 years (return period of about 2,500 years) except where subject to deterministic limitations (Leyendecker and Frankel, 2000). The recent 2012 IBC develops response spectra using a Risk-Targeted Maximum Considered Earthquake (MCER), which is defined as the response spectrum expected to achieve a 1% probability of building collapse within a 50-year period. The design-level response spectrum is calculated as two-thirds of the MCER ground motions. Since the MCER earthquake ground motions were developed by the USGS to incorporate the targeted 1% in 50 years risk of structural collapse based on a generic structural fragility, they are different than the ground motions associated with the traditional MCE. Although site response is evaluated based on the MCER, it should be noted that seismic hazards, such as liquefaction and soil strength loss, are evaluated using the Maximum Considered Earthquake Geometric Mean (MCEc) peak ground acceleration (PGA), which is more consistent with the traditional MCE. The 2012 IBC design methodology uses two mapped spectral acceleration parameters, Ss and Si, corresponding to periods of 0.2 and 1.0 sec to develop the MCER earthquake. The Ss and Si parameters for the site located at the approximate latitude and longitude coordinates of 45.4124°N and 122.7740°W are 0.96 and 0.42 g, respectively. Estimated Site Response The effect of a specific seismic event on the site is related to the type and quantity of seismic energy delivered to the bedrock beneath the site by the earthquake and the type and thickness of soil overlying the bedrock at the site. A ground-motion hazard analysis was completed to estimate this site-specific behavior in accordance with Section 21.2 of ASCE 7-10. The ground-motion hazard analysis consisted of four significant components: 1) estimation of bedrock response using recently developed attenuation relationships (deterministic evaluation), 2) estimation of bedrock response using the 2014 USGS-based PSHA (probabilistic evaluation), 3) comparison of the deterministic and probabilistic bedrock-response G RD C-5 spectra to determine the controlling spectrum, and 4) development of recommended response spectra for the four hazard levels. The following paragraphs describe the details of the ground-motion hazard analysis. To estimate the deterministic bedrock-response spectrum, recently developed attenuation relationships were used to evaluate bedrock ground motions at the site. Based on our review of the USGS deaggregations (U.S. Geological Survey, 2014), crustal seismicity and an event on the CSZ represent the largest contributing sources to the seismic hazard at the site. Considering this, we have chosen to estimate the deterministic bedrock response using 84th-percentile ground motions from the following two earthquake scenarios: 1) a Mw 7.0 crustal earthquake at a distance of 10 km from the site and 2) a Mw 9.0 subduction zone earthquake at a distance of 74 km from the site. The same attenuation relationships outlined in the deterministic section were used to evaluate the crustal and subduction earthquake response. The resulting deterministic bedrock-response spectra are shown on Figure 6C and indicate crustal seismicity controls the hazard at the site. The deterministic MCER bedrock spectrum is taken as the larger of the 84th-percentile ground motions and the deterministic lower limit. The probabilistic bedrock- response spectrum was acquired through the use of the USGS Interactive Deaggregation (U.S. Geological Survey, 2014). The deaggregation was evaluated for a 2% in 50 years probability over a period range of PGA to 5 sec. In accordance with Section 21.2 of ASCE 7-10, the site-specific bedrock MCER response spectrum is taken as the lesser of the probabilistic and deterministic MCER bedrock motions. Figure 6C demonstrates the probabilistic bedrock spectrum is the lesser of the spectra. The site is classified as Site Class D, or a stiff-soil site, based on the average Vs3o of 950 ft/sec in accordance with Section 20.3 of ASCE 7-10. Corresponding short-and long-period adjustment factors Fa and Fy of 1.12 and 1.58, respectively, were used to develop the probabilistic Site Class D MCER response spectrum. We recommend using the Site Class D MCER and design response spectra shown on Figure 7C for design of the new structure. Seismic Hazards Liquefaction/Cyclic Softening. The results of our evaluation indicate there is a potential that zones of the interbedded sandy silt and silty sand deposit below the groundwater surface at the site could lose strength or liquefy during a code-based earthquake. Based on our analysis, potentially liquefiable soils are present at a depth of 10 ft below the ground surface and extend to a depth of about 40 ft. Our analysis indicates the potential for 1 to 2 in. of seismically induced settlement, which may occur during the earthquake and after earthquake shaking has ceased. Other Hazards. Based on site topography, the risk of earthquake-induced slope instability and/or lateral spreading is low. The risk of damage by tsunami and/or seiche at the site is absent. The inferred location of the Canby-Mollala Fault underlies the site (Personius et al., 2003); however,the USGS does not consider the Canby-Mollala Fault to be an active, contributing source in their PSHA. The USGS considers the Portland Hills Fault, located about 12 km northeast of the site, to be the closest crustal fault source contributing to the overall seismic hazard at the site. Unless occurring on a previously unmapped or unknown fault, the risk of fault rupture at the site is low. G R C_6 CONCLUSIONS The 2012 IBC design methodology uses two spectral response parameters, Ss and Si, corresponding to periods of 0.2 and 1.0 sec to develop the MCER response spectrum. The Ss and Si parameters for the site are 0.96 and 0.42 g, respectively. The results of the ground-motion hazard analysis indicate the 2012 IBC Site Class D spectrum provides an appropriate estimate of the spectral accelerations at the site. We recommend use of the Site Class D design spectrum shown on Figure 7C for design of the new structure at the site. References Abrahamson, N.A., Gregor, N., and Addo, K., 2015, BC hydro ground motion prediction equations for subduction earthquakes, Earthquake Spectra In-Press. Adams, J., 1990, Paleoseismicity of the Cascadia subduction zone: Evidence from turbidites off the Oregon-Washington margin: Tectonics,vol.9,no.4,pp.569-583. Atkinson,G.M.,and Macias,M.,2009, Predicted ground motions for great interface earthquakes in the Cascadia Subduction Zone: Bulletin of the Seismological Society of America,vol.99,no.3, pp. 1552-1578. Atwater, B.F. and Hemphill-Haley, E., 1997, Recurrence intervals for great earthquakes of the past 3,500 years at northeastern Willapa Bay,Washington: U.S.Geological Survey Professional Paper 1576,p. 108. Atwater, B.F., Nelson, A.R., Clague, J.J., Carver, G.A., Yamaguchi, D.K., Bobrowsky, P.T., Bourgeois, J., Darienzo, M.E., Grant, W.C., Hemphill-Haley, E., Kelsey, H.M.,Jacoby, G.C., Nishenko, S.P., Palmer, S.P., Peterson, C.D.,and Reinhart, M.A., 1995, Summary of coastal geologic evidence for past great earthquakes at the Cascadia subduction zone: Earthquake Spectra. Boore, D.M., Stewart, J.P, Seyhan, E., and Atkinson, G.M., 2014, NGA-West2 equations for predicting PGA, PGV, and 5% damped PSA for shallow crustal earthquakes: Earthquake Spectra,August 2014,vol. 30, no. 3, pp. 1057-1085. Campbell, K. W., and Bozorgnia, Y., 2014, NGA-West2 ground motion model for average horizontal components of PGA, PGV, and 5%damped linear acceleration response spectra:Submitted to Earthquake Spectra. Chiou, B. S.J., and Youngs, R. R., 2014, Update of the Chiou and Youngs NGA model for the average horizontal component of peak ground motion and response spectra:Submitted to Earthquake Spectra. Clague,J.J., 1997, Evidence for large earthquakes at the Cascadia subduction zone: Reviews of Geophysics,vol. 35, no.4, pp.439- 460. Clague, J.J., Atwater, B.F., Wang, K., Wang, Y., and Wong, I., 2000, Penrose conference report-Great Cascadia earthquake tricentennial:GSA Today,vol. 10,no. 11,pp. 14-15. Fluck, P., Hyndman, R.D., and Wang, K., 1997, Three-dimensional dislocation model for great earthquakes of the Cascadia subduction zone:Journal of Geophysical Research,vol. 102,no.B9,pp.20539-20550. Goldfinger, C., 1994, Active deformation of the Cascadia Forearc-Implications for great earthquake potential in Oregon and Washington,Oregon State University,unpublished dissertation. Goldfinger, C., Nelson, C.H., and Johnson, J.E., 2003, Holocene earthquake records from the Cascadia subduction zone and northern San Andreas fault based on precise dating of offshore turbidites:Annual Review of Earth and Planetary Sciences 31,pp. 555-577. Guffanti, M., and Weaver, C.S., 1988, Distribution of Late Cenozoic volcanic vents in the Cascade Range-Volcanic arc segmentation and regional tectonic considerations:Journal of Geophysical Research,vol.93,no.B6,pp.6513-6529. Hughes,J.M.,and Carr,M.J., 1980,Segmentation of the Cascade volcanic chain:Geology,vol.8,pp. 15-17. Hyndman, R.D., and Wang, K., 1995, The rupture zone of Cascadia great earthquakes from current deformation and the thermal regime:Journal of Geophysical Research,vol. 100,no. B11,pp.22133-22154. Kelsey, H.M., and Bockheim, J.G., 1994, Coastal landscape evolution as a function of eustasy and surface uplift rate, Cascadia margin,southern Oregon:Geological Society of America Bulletin,vol. 106,pp.840-854. Kelsey, H.M.,Witter, R.C., and Hemphill-Haley, E., 2002, Pd:boundary earthquakes and tsunamis of the past 5500 yr, Sixes River estuary,southern Oregon:Geological Society of America Bulletin,vol. 114,no.3,pp.298-314. Kelsey, H.M., Nelson,A.R., Hemphill-Haley,E.,and Witter, R.C., 2005,Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone:GSA Bulletin,vol. 117,pp. 1009-1032. G R a C-7 Leyendecker, E.V., and Frankel, A.D., 2000, Development of maximum considered earthquake ground motion maps_Earthquake Spectra,vol. 16,no. 1. 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U.S.Geological Survey,2014, Unified hazard tool lookup by latitude, longitude,accessed 04/11/17 from USGS website: https://earthquake.usgs.gov/hazards/interactive/. Wang, Y., He, J., Dragert, H., and James, T.S., 2001, Three-dimensional viscoelastic interseismic deformation model for the Cascadia subduction zone:Earth,Planets and Space,vol.53,pp.295-306. Weaver, C.S., and Shedlock, K.M., 1989, Potential subduction, probable intraplate and known crustal earthquake source areas in the Cascadia Subduction Zone: U.S.Geological Survey Open-File Report 89-465,pp. 11-26. Weaver,C.S.,and Michaelson,C.A., 1985,Seismicity and volcanism in the Pacific Northwest-Evidence for the segmentation of the Juan de Fuca PI.:Geophysical Research Letters,vol. 12,no.4,pp.215-218. Witter, R.C. 1999, Late Holocene Paleoseismicity, tsunamis and relative sea-level changes along the south-central Cascadia subduction zone,southern Oregon: University of Oregon,unpublished Ph.D dissertation,pp. 178. Witter, R.C., Kelsey, H.M., and Hemphill-Haley, E., 2003, Great Cascadia earthquakes and tsunamis of the past 6700 years, Coquille River estuary,southern coastal Oregon:Geological Society of America Bulletin 115,pp.1289-1306. Wong, I.,2005, Low potential for large intraslab earthquakes in the central Cascadia Subduction Zone: Bulletin of the Seismological Society of America,vol.95,no.5. Youngs, R.R., Chiou, S.J., Silva, W.J., and Humphrey, J.R., 1997, Strong ground motion attenuation relationships for subduction zone earthquakes: Seismological Research Letters,vol.68,no. 1,pp. 58-73. Zhao,J.X.,Zhang,J.,Asano,A.,Ohno,Y.,Oouchi,T.,Takahashi,T.,Ogawa, H.,Irikura, K.,Thio, H.,Somerville, P.,Fukushima,Y., and Fukushima,Y.,2006,Attenuation relations of strong ground motion in Japan using site classification based on predominant period: Bulletin of the Seismological Society of America,vol.96,pp.898-913. G R El _ � 8 pco\i" 130°Q�4 126' 122°W O�w� St* 52°N PORTLAND NORTH AMERICA Cascades Go o fr. ERICA Coastilne Range Q PLATTE British �► r 1 1 r r 1 r `�� J \ Columbia $24.5 t24.0 123.5 123.0 122.5 122.0 121.5 !.,„.44•4.)) ALONGITUDE Q" EXPLORER O. • S PLATE A . •Vancouver)- Ld�j rAKa S Q DISTANCE IN KM Crustal faults d04, Ill N-�0 i"Q,0.a 10. 30. 50. 70. 90. 110. 130. 150. 170 190. 210. 230 250. 270. 290. y A 48` _ I l l l l l t l I, 1 1 1 1 o ---��g J i ~ j 1' Seattle tO. o o° ° 0 ,,,, o ce '"o'•Q an° R° 10. •m a°).". N Es 30. _ ° °° a,.„ p North America Platen 30. 6 Washington - o . o • ��, 0- ® 50. - Plate Crustal �' i r JUAN DE FUCA n \ x - Interface eandQ p aelsmtcity - / PLATE ;47 p PortlandQ = 70. _ °ce plate _70. NN\ p m 80. -' Intraslab earthquakes -90. 7 •c _ 64_ U L1 44° Ito._ _Ito. 0b paW Oregon - f2o r0 .0 130._ 130. PACIFIC PLATE ~ ~ --___ -- ISD.-1 1 1 I I T t tso. p� -- 124.8 124.0 123.5 123.0 122.5 122.0 121.5 Cr a GORDA A LONGITUDE tj PLATE California DEFORMATION B) EAST-WEST CROSS-SECTION THROUGH WESTERN OREGON AT THE LATITUDE OF PORTLAND,SHOWING THE SEISMIC �? 40' SOURCES CONSIDERED IN THE SITE-SPECIFIC SEISMIC HAZARD STUDY(MODIFIED FROM GEOMATRIX,1995) 0 200 km Mendocino Fault � -%d A) TECTONIC MAP OF PACIFIC NORTHWEST,SHOWING ORIENTATION AND EXTENT OF CASCADIA SUBDUCTION ZONE(MODIFIED FROM DRAGERT AND OTHERS,1994) [41RU TECTONIC SETTING SUMMARY JUNE 2017 JOB NO.5970-C FIG.IC 1• i t t. S t t AAA,, T> • e1 * =1 ro ; i ` ,�E. tt.. � '""i. t5-A. �', 9 �t .: I � s-m..„ � b r�r y Aq• w 1 A A Tss Its./- Yi \ , f k, C-. .✓ I y�:+ aI _ a+, F4 . M1 . Y - .,$a'\ -1P t f:'.1 nt;7r _ •s f '•(.'nr t _ ' :. jt"f T Wont + r { , jJ. - I Y t t Pal \l J_... a �, �; I L,L'A)h U ,v • r t {a°'rr try_II !ram• t I• ' 3 :� t 4' ! e T'4 .,?+ ., . :.00. Tm t s r }"mn,i 'n� .,yr,1 ,.,F �5 ,ta A a { 11 i_,__,� `- TC \ S s u.y r r w tit. ]: .z. , ; �; ,�j`� ,,,„ • A r, 'tt 7yu n 1t ., .:All' X+�:,�- ,r;r.. 's-. t+� '-. „,, .: t. a `�",, '+ '.,. .tw- +y \-s .. a:; '�- / , <>,,..,,„,..,.. .. 't i_ate Y • ` \ , °\/ ^ ( • i�'�"yw �'! V. „911007 'X fi� ...sT i T ryR' y '4f, has# ti 1s ' a(btA' ''?1. �'b A 1' rrx „'l'-+` ,� �. r C7 c% 1{' � t4°� us `r• Lo h .m� I^ s " z "; �$-' Tar ,-1 + + BBv t shii'�5 n r '` i ooa T t V4 u. , t. nor , ' -II sew` t a ,iy i stL ,- 1, ` 'sk .+„ Qlba.- '. �71- ,. 9t ,- ,,'' w �A _... X' '': � .tr,!i. I'tt~ J ,f1T `, g c, r �44, � �4� : ,..e. r a ..�4.4141,i0 � r.', •t4,ta.,„ -'.-'.. t • >s � :;Iri, tfm. :^�i' � ''' 3i %►''' al i it N.;, a iY ��.. ,, /. t r r 4• • lY � � � am �i4♦� � J �J�!".,+ ., L� p. Ott � �, :� �-'^`- s `.•{ FROM. ®. a ro. �.\ ).♦ - Ted '� fi "1 p 4 �� , ... ra�, .' dF -.. ,' 4y. .1r Tt_y i �. _ iY'-_t,, • r <'. han B � c r�: ,.',l IA .+. * �'�, �`�' "� ;,;+i !�'. IT"1t...- C` --S'..1' Ca• a re. . "fir dr+r'..-..rp„ , 'i R{#(, "°, a WALSH,El,NORM-C,MA,PHILIIPS,W.M.,LOGAN,R.L,AND 5CHA5SE,H.W., s .,.. 'k r'' w �j/y ;; '&; 51, `� 1987,GEOLOGIC MAP OF WASHINGTOFLSOUTIAMST QUADRANT;1:750,000: ',\' 1.."5:'4:14$23/4:51"641**,‘'.7.1.,::::?;',VP-'7,-; ., ;41:41i'.-t"-Zrve:.,„..' ' ' 14' ' deg.J ,(,. * Y I '' t -.T . Gr ,•,{ WASHMG10N f71VISNXd OF GEOIOG'I AND fAREH RESOURCES.6M-34 I , ,,,,,isi„,;,. i1 .+., `� . : �}� ,f �.,. • '• �1' /r 4\,'^+ ,.'"'sr .;" - WALKER,G.W.,AND MACLfOD,N.5.,1991,GEOLOGIC MAP OF ORECAN:U.S. ,h? -1 :� <:, T«- .�(\� ��].' . 1 nl� ��^`J ''� 'S".4 �' � ,� y �, cfoLocrcaLsuRVEv >, f tom, ,.�f_.._. ;_Rill* r .-.. 1�?'"�l•'.<t t•--'�, 1. j� r�a (t �/ /. ~ Sal `,..,`-.*ws1 ` Mr ,��, t`, ii,' -�-. .1°. Tse rtm,t �, (kJ-> 1 / Y` t .,,{ ( '_ ,�k, i ni , ,�,t ,y x-6` ,.),,ros ayt ,•, 010 20 MILES da r.R� ..� stilJoa' 7di i< t 4� Oc r: ^r.n � . �' Nti Tfc# !+ I . ._ rb,)v�.tqu ls�r t is - e,,,,t, l , �I YV�vt _ Ls"- -ra.: �j9 Trb Q9 KILOMETERS t , t , r\ ; 1 y ��"" � { ' 0 10 20 -` ,- U"7 is E ...r r x ! ` �,, , 1 s'?'i€� "t ole�� i..P``` �. � - , tx v \` Ty "-'7 4 .t ._ r/ f.'., - .Art, i •m, .. .. a S' Sdui, r: Contact—Approximately located �9—••• Fault—Dashed where inferred;dotted where concealed;queried where doubtful;ball and bar ondownthrownside REGIONAL GEOLOGIC MAP �?Z A• Thrust fault—Dashed where inferred;dotted where concealed;queried where doubtful; sawteeth on upper plate i Strike and dip of bed )UNE 2017 JOB NO.5970-C FIG.2C • -"h,^ CF _— r -..,..,..or.--- MAP EXPLANATION - �;\ Kelsoi ;' , d�''1 , •i,,,a�•a+' ,�,w (j TIME OF MOST RECENT SURFACE RUPTURE STRUCTURE TYPE AND RELATED FEATURES ` - ... ,Y a'4 r Y �".,v., " — Fmk..re(<10000 years)or post last Maclean Mt 5.000 years:151a): —L Normalw Mgharyls reverse fault a 'j.F f- l�#�S s!`- '� f,•` f no h alals ruptures in Oregon b date —a.-- Slnkastm fault T 71< -W penWlimate gleaatron) y- Thrust fault Gearhart 5 y "s ',,, ', ._ Late Duaarne 100000. d '� '\ P*,g A" .A =c gir'S ,. l s,=` `, — Late and middle Quaternary l<150 OW years 750lea) —{— Anticlinal fold side r { � = _ Oualerrary undpterendaa0l<1,60000p years,<1.6 Me) -� Syndlnal fold Class B structure(age a --t-- Moriocfinal lab ,y 4.� 1 ":1' 'k`#' ^fyc` a. SLIP RATE urge tllreclbn d fold s '�' ; '' y - AS mm,Year I Fault section marker 3Ch '�1. Aw r -..", } — 10-50mmyear " l 718t St.Helens ' °� " DETAtLEDsguorsnes t -$ — o.x-1.ommyear {7B }Y� yx ; i r — <0.2 mm/ye r a -. (`"'n P I Subducnon zone saby f m ne rf 1 e '";,f TRACE a sne f Welty yy '.'4 i -• �. ,.�s^^♦1 Mosny continuous al map st'ak � 'CULTURAL AND GEOGRAPHIC FEATURES Mostly at map soak --"' Divbed highway to . ..€.0at4 - J f ��580 arr o concealed roman«secondaryroad r - Permanent dyer Or stream a 877 ` G ' Vancouver ram^ a4 mre mnem mer or aneam 1 .-•;! ;. i - Permanent or intermittent take ash Garibaldi ! k'" ;714 <-, ^ ,880 867�� ," .e 1, f _ ' .r-' FAULT NUMBER NAME OF STRUCTURE Bay City # S Forest Grove ' gn •1 714 HELVETIA FAULT • 715 BEAVERTON FAULT -881 r\ Hillsboro 875\ S "t 87'8, M: 716 CANBY-MOLALLAFAULT 882 c y T ' ` + 879 868[ 866 717 NEWBERG FAULT "-- Tillamook 4'• p 447 \ 715 ,,,, �f� - Sy 716 �. `{r` t _ 718 GALES CREEK FAULT ZONE .4J k,�� 1 r ,�`"--•` ^ 719 SALEM-EOLA HILLS HOMOCLINE .1 W a- `I 1 I �� %` _ 864 CLACKAMAS RIVER FAULT ZONE ' , Portland �i I = >. SITE Ir •'879 ,, ) 867 EAGLE CREEK THRUST FAULT Y- 717 s 868 BULL RUN THRUST FAULT 5 '�4. - Ati Area of 872 WALDO ANGELHILLS FAULT T Newberg _ 813 MOUNT FAULT HOOD , ,r^. z. t". Portland map ,s ,a^ 874 BOLTON FAULT Canby t?s, 875 OATFIELD FAULT ..jers` McMinnville l' 1 al 876 EAST BANK FAULT Dayton Hubbard ..''''.,716877 PORTLAND HILLS FAULT 878 GRANT BUTTE FAULT Molalla ti„j`w'� Sheridan Woodburn 879 DAMASCUS-TICKLE CREEK FAULT ZONE Amity 880 LACAMAS LAKE FAULT a 881 TILLAh100K BAY FAULT ZONE t Silverton •.` 873 FROM: PERSONIUS,S.F.,AND OTHERS,2003,MAP OF QUATERNARY FAULTS AND ` ± 1 FOLDS IN OREGON,USGS OPEN FILE REPORT OFR-03-095. -p.. - s. a^ Salem i 4 s Dallas s sr 719vI �I „, €"= - Independence ir ,872 �� 864 `., r' ' , 0 10 20 MILES 884 �` Monmouth r, 81 I I FT 1- -'---3 871 Stayton `' AP.\I 0 20 40 KILOMETERS S ,719 1,., Mill City y_ �. - R LOCAL FAULT MAP JUNE 2017 JOB NO.5970-C FIG.3C _.` 48°N '� �� » f 5 Was hiriggtoii:: 46°N , '' x —4 y ap FIGURE 21. LOCATION OF THE EASTERN EDGE OF EARTHQUAKE RUP- TURE ZONES ON THE CASCADIA SUBDUCTION ZONE FOR THE VARIOUS MODELS USED IN THIS STUDY RELATIVE TO THE SURFICIAL EXPRESSION OF THE TRENCH:TOP,BASE OF THE ELASTIC ZONE;MID,MIDPOINT OF 44°N THE TRANSITION ZONE;BOTTOM,BASE OF THE TRANSITION ZONES; ,. BASE,BASE OF THE MODEL THAT ASSUMES RUPTURES EXTEND TO . - ABOUT 30-KILOMETERS DEPTH.FIGURE PROVIDED BY RAY WELDON. 42°N - t. mid —9 P m, bottom , - base 126°W 124°W 122°W FROM: PETERSEN,MD,FRANKEL,AD,HARMSEN,SC, AND OTHERS,2008,DOCUMENTATION FOR THE 2008 UPDATE OF THE UNITED STATES NATIONAL SEISMIC HAZARD MAPS:US GEOLOGICAL SURVEY,OPEN FILE REPORT 2008-1128 G RO ASSUMED RUPTURE LOCATIONS (CASCADIA SUBDUCTION ZONE) JUNE 2017 JOB NO. 5970-C FIG. 4C 0.0009 — 0.0008 0.0007 w d 0.0006 cc 0 0.0005 cc 0.0004 < 0.0003 — 0.0002 - 0.0001 0r 7.8 8 8.2 8.4 8.6 8.8 9 9.2 9.4 MOMENT MAGNITUDE Figure 22. Magnitude-frequency distribution of the Cascadia subduction zone. FROM: PETERSEN,M,FRANKEL,A,HARMSEN,5, AND OTHERS,2008,DOCUMENTATION FOR THE 2008 UPDATE OF THE UNITED STATES NATIONAL SEISMIC HAZARD MAPS:US GEOLOGICAL SURVEY,OPEN FILE REPORT 2008-1128 GRD ASSUMED MAGNITUDE-FREQUENCY DISTRIBUTION (CASCADIA SUBDUCTION ZONE) JUNE 2017 JOB NO. 5970-C FIG. 5C i . „ 2.2 Deterministic Bedrock Response Spectrum r , Based on Portland Hills Fault Hazard 2.0 / (84th Percentile Ground Motions) 1 1.8 1 I / Deterministic Lower Limit Response Spectrum 1.6 I / / 1.4 I Probabilistic Bedrock Response Spectrum 00 I Based on 2% in 50-Year Hazard c ' (USGS 2014 Deaggregation) L 1.2 Ii_ I,I a� v u v Q w 1.0 it U o, —I \ Deterministic Bedrock Response Spectrum "' 1 I / Based on Subduction Zone Hazard 0.8 'e j (84th Percentile Ground Motions) IIII� I 0.6 I A \ v 0.4 I \ \�� :: : I 1 2 3 4 Period,T, seconds GR0 DETERMINISTIC VS PROBABILISTIC BEDROCK RESPONSE SPECTRA (5%DAMPING) JUNE 2017 JOB NO. 5970-C FIG. 6C 1.2 1.0 0.8 c Spectrum Recommended MCER Response S o � / � p 0.6 L � U '1' Recommended Design Response Spectrum 0.4 0.2 0.0 0 1 2 3 4 Period, T, seconds G Rfl DESIGN AND RECOMMENDED MCE RESPONSE SPECTRA R (5%DAMPING) JUNE 2017 JOB NO. 5970-C FIG. 7C 'OFFICE COPY , , ,,, , f,,,,,,p__ _ If i 1 ',W-'i i'.� I i _ /S TrlMet�Tigard - '\ : " ' > ' / �`/' TransitCenter Park_ "' 'I /)/ , �f�Y i _ ) 1, S RS I i' \ SWtFONNE .. j c, ;\ j / i , ' --, O,,, �.yJ: -� \ S �% / i Q � 1 ) ° TIC I � t �, �` �° v►� l ® ,, �p� 1 Farm° "sm. I� y3 y> Pt' SW OMARA ST �� \ < _ � i like.;'\- 5� �' r 1 rl• � 7 SWFDGEWOODST L��• � � `�,. thon m�)1 j I'i! � SWMCDONALDST ,-) _11', J ��! ) 'so `'_ `• � - \ V _ t iY,�r2._._ .. � l , ( ' � `1.. � 0 - ,nL /u\ i1II` Cp> ,0 � .1,1 - ' _ >) = B�Anit$ . 0 � # 106�'SW MCFAy _}Tigard !---.1- -.--,---o : K ', i '' . /,_ -; Evangelical Cer / ems-_ o• a ^` C, csMfl , "ERBURY LN ''' ">® /-7-1 ,1 *ST " ,,J , < SW PINEBR00/ , i the ingLutheran /,/ ,y! ) — J ) ` -'. C"''Firark�a Ride ,r, < < i '� -' }' = ; ;)1.);.,•_ ,-/,-- ��! -:-> • 1 I;, •�� r�. • i I , is SW-n,- J — I 1 , „o, a ; ) I .) QINGST L'• j�1 ...-, N • SW LADY MAR%pN,DR �� Q 1 it ;•;, ie ��\\ 35o P ama! a x, ��f --1,8 / pR" - —'' o ems I pQ _ uni-`gF�E.ST pR \-' :-' i) ORO.S (�(, 11 GGrn �-' µ1GHLANO Q i�sl ED ~ 1 `!.. 11 l D /SWSUMMEREIL , ,., C ,_ 11, nSfSN-CENTUP_oJ _ .� � SW DURHAMJR �/ )I SW-DURHAM RD >` RLES/AVE °, , in <' ( j , Q -_j% • 1 / el.... 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DMTW q at 1 I t TW + '' 4'' ij( t ,U /, ( 1/,' f .•';' i; 7 Ld2'r 1 / B•2TW ( r % 1 I/ / ' 7 (wJl i / fr 1/jam Itl i ` :Av ,.., f 7• •, 0 TWALITY MIDDLE SCHOOL ! �1 t 11 v le 'il 7n. i .�o ,,,,..,,,_: / i� l ( 1t o-S� I. � i •j•l t A. t` V B 3TW " +94 r A r. /� :,, /,,,,,,:.:,,1T-Fs /— 'J CPT{ / • CONE PENETRATION TEST COMPLETED BY GRI -1„'.i - -. i /t ` / % ,ft,� (MAY 5,2017) ' >"- {_'s,x _ Q DILATOMETER COMPLETED BY GRI / '"I\� (MAY 5,2017) {r '/ t J �'' BUILDING ING 'rg -r 14 ,%,/ DIUTOMETER COMPLETED BY GRI ' •� C (MAY 5,2017) —y; // k 1 '�r2�' - % /D//', y, �' CONE PENETRATION TEST COMPLETED BY GRI r/ 1. ) u= \y .�k- '/ , , / "`4.u-.4' (MAY 4-5,2017) 7 DMT-1 ...-4 BORING COMPLETED BY GRI 3, ty ti: (MAY3-4,2017) '�'`'� '" o0.ySCV�� ~ r_ ' / f// ', -•"+�' I • BORING COMPLETED BY GRI _+ �'` �N'( �...�. -),..f y - 7/- t / (MAY3-4,2017) 4 ow•e l rJ,//, .( / / / _ /!11 - „ ,idf,' \ SITE PLAN FROM FILE BY DAY CPM SERVICES,LLC I EMQ� n c- ,-,-,;/, / / } ^ / / i ern\, —�` '``!�� /: //// % I /1't ( ii li ' III 0 120 240 FT 1 ,%(� /�-'1-\ � �� I )Al"'. TIGARD TUALATIN SCHOOL DISTRICT i1 ', •�I I ( ,1 -o( I I •,••I / \�fir/,� 1� h ®®D TEMPLETON ELEMENTARY SCHOOL a( Irlk la-3 ca\ki ,'r� I�� / / /y , c" ii' i 1 o r,A r ,aU .,` r i i 4v(i e ' SITE PLAN LUNE 2017 JOB NO.5970C FIG.2 ey • /V a SEAL WITH ON-SITE 3I41N.-MINUS CRUSHED ROCK WITH LESS THAN 5%PASSING NO.200 SIEVE /IMPERVIOUS MATERIAL (WASHED ANALYSIS) / SLOPE TO DRAIN •••••••••r— . Z P/ / /////i 2IN.1 CONCRETE SLAB •I II •'o •• OVARIES • •• (2 IN.MIN.) BIN.(MIN.) VAPOR-RETARDING MEMBRANE SYSTEM ::00011 • • III \ 1 T GRANULAR BACKFILL COMPACTED TO ABOUT 95%OF THE MAXIMUM (MIN.)> .< • SEE DETAIL'A'FOR TYPICAL ROCK OF UP TO 2-IN.SIZE WITH 4-IN.-DIAMETER PERFORATED DRAIN PIPES DRY DENSITY AS DETERMINED BY _ UNDERSIAB RECOMMENDATIONS NOT MORE THAN 2%PASSING THE ARE TYPICALLY PLACED ON 20-FT CENTERS ASTM D 698 NO.200 SIEVE(WASHED ANALYSIS) AND SLOPED TO DRAIN(SEE NOTE 2) • TEMPORARY CONSTRUCTIONIIIIIIIIIIF�a DETAIL'A' SLOPE NOT TO SCALE 172 TO3/3 GRAVEL WITH LESS THAN 2%PASSING THE NO.200 SIEVE(WASHED ANALYSIS) UNDERSLAB DRAIN 4-1NMIAMETER PERFORATED MASTIC DRAIN PIPE,SLOPE TO DRAIN NOTES: 1) A VAPOR-RETARDING MEMBRANE SYSTEM IS RECOMMENDED FOR MOISTURE-SENSITIVE AREAS AND SHOULD BE INSTALLED IN ACCORDANCE WITH MANUFACTURER'S RECOMMENDATIONS. 2) INTERNAL 4-IN.-DIAMETER PERFORATED DRAIN PIPES ARE TYPICALLY PERIMETER DRAIN NOT NECESSARY IN THOSE AREAS WHERE THE FINISH FLOOR WILL BE ABOVE EXISTING SITE GRADES. �� TT TA SCHOOL DIICT TEMPLARETONUA ELEMENTARY SCHOOL TYPICAL SUBDRAINAGE DETAILS JUNE 2017 JOB NO.5970-C FIG.3 • < X=mH > • LINE LOAD,QL STRIP LOAD,q A A /� / A ��op �7�� 2 Z=nH MEP 01.1. If Form S 0.4: H ah= QL 0.2n H (0.16+ n2)2 Form >0.4: ah= Q (/3-SIN/3 COS 2a) Tr an ah— QL 1.28m2n ah H (m2+n2)2 (/3 in radians) LINE LOAD PARALLEL TO WALL STRIP LOAD PARALLEL TO WALL < X=mH > POINT LOAD,Qp A A Z=nH IMP For m S 0.4: A� W �`A' ah = Qa 0.28n2 H mr H2 (0.16+ n2)3 For m>0.4: Op 1.77m2n2 ah ah = (m2+ n2)3 a'h=ah COS2(1.10) NOTES: O ah 1. THESE GUIDELINES APPLY TO RIGID WALLS WITH POISSON'S A A RATIO ASSUMED TO BE 0.5 FOR BACKFILL MATERIALS. e O 2. LATERAL PRESSURES FROM ANY COMBINATION OF ABOVE a h LOADS MAY BE DETERMINED BY THE PRINCIPLE OF SUPERPOSITION. X=mH > DISTRIBUTION OF HORIZONTAL PRESSURES VERTICAL POINT LOAD G Mill TIGARD TUALATIN SCHOOL DISTRICT TEMPLETON ELEMENTARY SCHOOL SURCHARGE-INDUCED LATERAL PRESSURE JUNE 2017 JOB NO.5970-C FIG.4