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Application APPLICANT 10/14/2022 (2)
REPORT OF GEOTECHNICAL ENGINEERING SERVICES A Street Mixed -Use Project 702 North A Street Springfield, Oregon For Northwest Sustainable Properties July 20, 2021 Project: NWSProp-2-01 July 20, 2021 Northwest Sustainable Properties 2959 NW Monte Vista Terrace Portland, OR 97210 Attention: Jean-Pierre Veillet N V 5 Report of Geotechnical Engineering Services A Street Mixed -Use Project 702 North A Street Springfield, Oregon Project: NWSProp-2-01 NV5 is pleased to submit this report of geotechnical engineering services for Phase 1 of the proposed mixed-use development located at 702 North A Street in Springfield, Oregon. Our services for this project were conducted in general accordance with our proposal dated June 2, 2021. We appreciate the opportunity to be of service to you. Please call if you have questions regarding this report. Sincerely, NV5 r awn M Dimke, P.E.. G.E. Principal Engineer oc: Cynthia Schuster, LRS Architects (via email only) TAP. NNP. SMD'. kt Attachments One copy submitted (via email only) Document lD. NWSProp-2-01-072021-geor docx © 2021 NV5. All rights reserved 9450SWCOMMECECI aE,SUnE300 I Wu IILLEOR97070 I www NV5com I Or CE5039688787 EXECUTIVE SUMMARY Based on explorations and analysis, it is our opinion that the site can be developed as proposed. Our specific recommendations for site developmentand design are provided in this report. The following geotechnical items will have an impact on design and construction of the proposed project: • Based on the proposed development configuration, the buildingcan be supported on shallow foundations bearingon either minimum 2-foot-thick gravel pads or on aggregate pier ground improvementthat extends to dense native gravel encountered atdepths between 10.5 and 13 feet BGS. Aggregate piers, if used, will allow for significantly higher allowable bearing pressures. • Based on the soil and groundwater conditions, liquefaction and lateral spreading potential is low for the site. • The fine-grained soi l present on the site is easi ly distu rbed during the wet season or when above the optimum moisture content for compaction. The subgrade will be above the optimum moisture content for compaction and sensitive to disturbance after demolition of surfacepavement. If not carefully executed, site earthwork can create extensive soft areas and significant repair costs can result. Subgrade protection consisting of granular haul roads and working blankets and/or the use of the existing pavement sections should be used. • The on-site fine-grained soil, which consists mostly of high plasticity clay, is not suitable for use as structural fill. The gravel encountered below depths between 10.5 and 13 feet BGS can be used as structural fill, provided it is properly moisture conditioned: however, significant excavations into the underlying gravel are not anticipated. TABLE OF CONTENTS PAGE NO. :1N:i01111LTA F9:101H:1:i:iai9C1IN] 061 1.0 INTRODUCTION 1 2.0 PURPOSE AND SCOPE 1 3.0 SITE CONDITIONS 2 3.1 Surface Conditions 2 3.2 Subsurface Conditions 2 4.0 SITE DEVELOPMENT RECOMMENDATIONS 3 4.1 Site Preparation 3 4.2 Construction Considerations 4 4.3 Excavation 4 4.4 Materials 5 4.5 Erosion Control 9 4.6 Drainage Considerations 9 4.7 Permanent Slopes 10 5.0 FOUNDATION SUPPORT 10 5.1 General 10 5.2 Shallow Foundations on Gravel Pads 10 5.3 Shallow Foundations on Aggregate Pier Ground Improvement 11 5.4 Lateral Resistance 11 5.5 Construction Considerations 12 6.0 FLOOR SLABS 12 7.0 RETAINING STRUCTURES 12 7.1 Wall Design Parameters 12 7.2 Wall Drainage and Backfill 13 7.3 Retaining Wall Backfill 13 8.0 PAVEMENT 14 9.0 SEISMIC DESIGN PARAMETERS 15 10.0 OBSERVATION OF CONSTRUCTION 15 11.0 LIMITATIONS 15 FIGURES Vicinity Map Figure 1 Site Plan Figure 2 TABLE OF CONTENTS PAGE NO. APPENDICES Appendix A Field Explorations A-1 Laboratory Testing A-1 Exploration Key Table A-1 Soil Classification System Table A-2 Boring Logs Figures A-1 - A-6 Atterberg Limits Test Results Figure A-7 Consolidation Test Results Figure A-8 Summary of Laboratory Data Figure A-9 SPT Hammer Calibration Appendix B Shear Wave ReMi Analysis B-1 Earth Dynamics LLC Report Appendix C Site -Specific Seismic Hazard Evaluation C-1 Quaternary Fault Map Figure C-1 Historical Seismicity Map Figure C-2 MCER Figure C-3 Design Response Spectrum Figure C-4 BSE Adjusted Accelerations Figure C-5 ACRONYMS AND ABBREVIATIONS AC asphalt concrete ACP asphalt concrete pavement ASCE American Society of Civil Engneers ASTM American Society for Testing and Materials BGS below ground surface BSE Basic Safety Earthquake CSZ Cascadia subduction zone DSHA deterministic seismic hazard analysis fps feet per second g gravitational acceleration (32.2 feet/second2) H horizontal to vertical km kilometers VICE maximum considered earthquake MCER risk -targeted maximum considered earthquake MRC maximum rotated component NA not applicable OSHA Occupational Safety and Health Administration OSSC Oregon Standard Specifications for Construction (2021) pcf pounds per cubic foot PG performance grade psf pounds per square foot PSHA probabilistic seismic hazard analysis psi pounds per square inch ReMi refraction microtremor SOSSC State of Oregon Structural Specialty Code SPT standard penetration test UHS uniform hazard spectrum USGS U.S. Geological Survey Vs30 shear wave velocity for the upper 100 feet (30 meters) 1.0 INTRODUCTION This report presents the results of our geotechnical engineering services for Phase 1 of the propose mixed-use development located at 702 North A Street in Springfield, Oregon. The site location relative to surrounding physical features is shown on Figure 1. We understand the project will include an eight -story, mass timber construction build ingwith commercial space on the ground floor and residential above. The existing Buick dealership will be renovated, and an existing garage building will be demolished for the parking lot north of the new building and renovated dealership. We understand a future Phase 2 of the project may include anew building with a minimum height of 25 feet in the parking lot location. Accordingto Holmes (the structural engineer), preliminary live and dead loads on the foundation columns will be 60 kips and 135 kips, respectively. Acronyms and abbreviations used herein are defined above, immediately following the Table of Contents. 2.0 PURPOSE AND SCOPE The purpose of this evaluation was to provide geotechnical engineering recommendations for use in design and construction of the proposed development. Specifically, we completed the following scope of services: • Reviewed readily available, published geologic data and our in-house files for existing information on subsurface conditions in the site vicinity. • Drilled three borings using mud rotary drilling methods near the building location to depths between 21.5 and 39 feet BGS. We also drilled three borings using hollow -stem auger drilling methods within the proposed parking area to depths between 11.5 and 16.5 feet BGS. • Classified the material encountered in the explorations, maintained a detailed log of each exploration, and collected samples at representative intervals. • Conducted ReMi geophysical testing to evaluate the shear wave velocity profile for the seismic hazard evaluation. • Conducted a laboratory testing program that included the following tests: • Twenty-two moisture content determinations in general accordance with ASTM D2216 • Two particle -size analyses in general accordance with ASTM D1140 • Two Atterberg limits test in general accordance with ASTM D4318 • Two dry density tests in general accordance with ASTM D7263 • One consolidation test in general accordance with ASTM D2435 • Provided recommendations for site preparation and grading, including temporary and permanent slopes, fill placement criteria, suitability of on-site soil for fill, and subgrade preparation. • Provided recommendations for wet weather construction. • Provided foundation support recommendations for the proposed structure. • Provided recommendations for use in design of conventional retaining walls, including backfill and drainage requirements and lateral earth pressures. • Evaluated groundwater conditions at the site and provided general recommendations for dewateringduringoonstruction and subsurface drainage. • Provided recommendations for AC pavement design and pavement subgrade preparation • Provided BSE seismic design parameters BSE -1N and BSE -2N in accordance with ASCE 41-17 for the seismic evaluation of the existing building renovation. • Performed a site-specific seismic hazard evaluation for the proposed development in accordance with ASCE 7-16 and the 2019 SOSSC. 3.0 SITE CONDITIONS 3.1 SURFACE CONDITIONS The site is generally level and is bound by B Street to the north, an AC -paved parking lot and singe -story U.S. Postal Building to the east, A Street to the south, and North 7th Street to the west. The site is developed with a single -story commercial building with an approximately 8,200 -square -foot footprint and a small garage with an approximately 1,100 -square -foot footprint. The remainder of the site is surfaced with AC pavement. 3.2 SUBSURFACE CONDITIONS 3.2.1 General Subsurface conditions were explored by drilling six borings (B-1 through B-6) to depths between 11.5 and 39 feet BGS. In addition, we conducted ReMi geophysical testing to evaluate shear wave velocities at the site. The boring locations and ReMi array location are shown on Figure 2. The exploration logs and results of laboratory testing are presented in Appendix A and the results of the ReMi testing are presented in Appendix B. Subsurface conditions generally consist of very soft to medium stiff clay overlying dense to very dense gravel. Fill was encountered in borings B-1 and B-3 to depths of 2 and 4 feet BGS, respectively. The following sections provide a detailed description of each geologc units encountered at the site. 3.2.2 Surficial Materials All of the explorations were surfaced with AC that generally ranged between 2 and 3.5 inches thick, except at boring B-6 where the AC was 8 inches thick. An 2 -inch -thick oil matwas observed beneath the AC in boring B-4. Aggregate base (3 to 8 inches thick) was observed beneath the AC in borings B-1 through B-5. 3.2.3 Fill Fill was observed in borings B-1 and B-3. The fill in boring B-1 consists of loose, silty sand with organics and extends to a depth of 2 feet BGS. The fill in boring B-3 consists of medium dense, silty gravel with wood and concrete debris and extends to a depth of 4 feet BGS. 3.2.4 Native Clay Native clay was encountered beneath the surfcial material in borings B-2 and B-4 through B-6 and beneath the fill in borings B-1 and B-3. The consistency of the clay is variable but is generally very soft to medium stiff. Based on laboratory testing, the clay is highly plastic and had a moisture content between 36 and 51 percent at the time of our explorations. Boring B-2 was completed at a depth of 11.5 feet BGS within the clay deposits. 3.2.5 Native Gravel and Silty Sand Native gravel and sand are present beneath the clay in borings B-1 and B-3 through B-6. The gravel contains varying amounts of silt and sand throughout the site. Siltysandwas encountered in boring B-1 between 9.5 and 10.5 feet BGS. Based on SPT blow counts, the gravel is generally dense to very dense and the silty sand is medium dense. 3.2.6 Groundwater Groundwater was observed in boring B-3 ata depth of 13 feet BGS during drilling and rose to 9.3 feet BGS after the boring was allowed to stay open for two hours. A review of published water well logs in the site vicinity indicates seasonal groundwater levels generally vary between S and 12 feet BGS. The depth to groundwater will fluctuate in response to seasonal changes. 900 1I1all :k9aU]Julg0111111I]QdUululak,UL\ID] OK 4.1 SITE PREPARATION 4.1.1 Demolition Demolition should include removal of existing concrete slabs, concrete curbs, abandoned utilities, basement walls, foundations, and other buried elements. Demolition material should be transported off site for disposal or recycled and used on site if the material is acceptable for use as structural fill. The sides and bottom of excavations should be cut into firm material and sloped at an inclination no steeper than 1%H:1V prior to installing structural fill. The resulting excavations should be backfilled with structural fill. 4.1.2 Stripping and Grubbing If present, trees, shrubs, and topsoil should be removed from all proposed structural fill, pavement, and building areas and for a 5 -foot margn around these areas. Stripped material should be transported off site for disposal or used in landscaped areas. In addition, root balls should be grubbed out to the depth of the roots, which could exceed 3 feet BGS. Depending on the methods used to remove the root balls, considerable disturbance and loosening of the subgrade could occur during site grubbing. We recommend that soil disturbed during grubbing operations be removed to expose firm, undisturbed subgrade. The resulting excavations should be backfilled with structural fill. 4.1.3 Subgrade Evaluation Upon completion of demolition and site stripping, and prior to the placement of fill or pavement improvements, the exposed subgrade should be evaluated by probing or proof rolling. After demolition of surface pavements and during wet weather, subgrade evaluation should be performed by probing with a foundation probe rather than proof rolling. Proof rolling, where used, should be conducted with a fully loaded dump truck or similarly heavy, rubber -tire construction equipment to identify soft, loose, or unsuitable areas. A member of our geotechnical staff should observe the proof rolling to evaluate yielding of the ground surface and/or con duct the proving. Areas that appear soft or loose should be improved in accordance with subsequent sections of this report. 4.2 CONSTRUCRON CONSIDERA BONS The fine-grained soil present on this site is easily disturbed. If not carefully executed, site preparation and utility trench work can create extensive soft areas and significant subgrade repair costs can result. If construction is planned when the surficial fine-grained soil is wet or above the optimum moisture content for compaction, the construction methods and schedule should be carefully considered with respect to protecting the subgrade to reduce the need to over-excavate disturbed or softened soil. The project budget should reflect the recommendations below if construction is planned during wet weather or when the surficial soil is above the optimum moisture content for compaction. If construction occurs when the fine-grained subgrades may be exposed to wet weather or are above the optimum moisture content, site preparation activities may need to be accomplished using track-mounted excavating equipment that loads removed material into trucks supported on granular haul roads. The thickness of the stabilization material for haul roads and staging areas will depend on the amount and type of construction traffic. In general, a 12-to 18-inch- thick mat of stabilization material is sufficient for light staging areas and the basic building pad but is generally not expected to be adequate to support heavy equipment or truck traffic. The granular mat for haul roads and areas with repeated heavy construction traffic typically needs to be increased to between 18 and 24 inches. The actual thickness of haul roads and staging areas should be based on the contractor's approach to site development and the amount and type of construction traffic. The imported granular material should be placed in one lift over the prepared, undisturbed subgrade and compacted using smooth-drum, non-vibratory roller. In addition, a geotextile fabric should be placed as a barrier between the subgrade and imported granular material in areas of repeated construction traffic. The imported granular material and the geotextile fabric should meet the specifications in the "Materials" section. It is possible to use the existing AC and/or aggregate base as part of haul roads and staging areas for subgrade protection. As an alternative to thickened crushed rock sections, haul roads and utility work zones may be constructed using cement-amended subgrades overlain by a crushed rock wearing surface. If this approach is used, the thickness of granular material in staging areas and along haul roads can typically be reduced to between 4 and 8 inches. This recommendation is based on an assumed minimum unconfined compressive strength of 100 psi for subgrade amended to a depth of 12 to 16 inches. The actual thickness of the amended material and imported granular material will depend on the contractor's means and methods and, accordingy, should be the contractor's responsibility. Cement amendment is discussed in the "Materials" section. 4.3 EXCAVATION 4.3.1 Temporary Excavations and Slopes Excavations will be required for the installation of new foundations, utilities, and other earthwork activities. Conventional earthmoving equipment in proper working condition should be capable of making the necessary excavations. Temporary excavation sidewalls in silty soil may stand vertical to a depth of approximately 4 feet, provided groundwater seepage does not occur. Excavations deeper than 4 feet will require shoring or should be sloped. Sloped excavations may be used to vertical depths of 10 feet BGS and should have side slopes no steeper than 1H:1V, provided groundwater seepage does not occur. If slopes greater than 10 feet high are required, NV5 should be contacted to make additional recommendations. Deeper excavations will contain gravel and debris, which could result in excavations being larger than anticipated because of caving. We recommend a minimum horizontal distance of 5 feet from the edge of existing improvements to the top of temporary slopes. All cut slopes should be protected from erosion by covering them during wet weather. If seepage, sloughing, or instability is observed, slopes should be flattened or shored. 4.3.2 Temporary Dewatering Groundwater was approximately 9.3 feet BGS at the time of our explorations and dewatering may be required to maintain dry working conditions for trench excavations. A sump located within the trench excavations may remove accumulated water, dependingon the amount and persistence of water seepage and the length of time the trench is left open. In addition, the sidewalls of trench excavations will need to be flattened or shored if seepage is encountered. Positive control of groundwater via pumpingfrom wells may be required for deeper excavations. Flow rates for dewateringare likely to vary dependingon location, soil type, and the season during which the excavation occurs. Dewatering systems should be capable of adaptingto variable flows. Where groundwater and fine-grained subgrades are present in excavations, we recommend placing at least 1 foot to 2 feet of stabilization material at the base of the excavations. Trench stabilization material should meet the requirements provided in the "Materials" section. 4.3.3 Safety All excavations should be made in accordance with applicable OSHA and state regulations. While this report describes certain approaches to excavation, the contractor should be responsible for selecting excavation and dewatering methods, monitoring the excavations for safety, and providing shoring as required to protect personnel and adjacent utilities and structures. 4.4 MATERIALS 4.4.1 Structural Fill Structural fill includes fill beneath foundations, slabs, pavement, any other areas intended to support structures, or within the influence zones of structures. Structural fill should be free of organic material and other deleterious materials and, in general, should consist of particles no larger than 4 inches in diameter. Recommendations for suitable fill material are provided in the following sections. 4.4.1.1 On -Site Soil The on-site soil near the planned foundation elevation will consist primarily of high plasticity clay and will not be suitable for structural fill. The gravel soil located at deeper depths will generally be suitable for use as structural fill, provided it can be adequately moisture conditioned; however, significant excavations into the underlying gravel are not anticipated. On-site coarse-grained soil should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. 4.4.1.2 Imported Granular Material Imported granular material should be pit -or quarry -run rock, crushed rock, or crushed gravel and sand that is fairly well graded between coarse and fine and has less than 5 percent by dry weight passingthe U.S. Standard No. 200 sieve. All granular material must be durable such that there is no degradation of the material during and after installation as structural fill. The percentage of fines can be increased to 12 percent if the fill is placed during dry weather and provided the fill material is moisture conditioned for proper compaction. The material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. During the wet season or when wet subgrade conditions exist, the initial lift should have a maximum thickness of 18 inches and should be compacted by rolling with a smooth -drum, non -vibratory roller. 4.4.1.3 Recycled Concrete Recycled concrete can be used for structural fill, provided the concrete is broken to a maximum particle size of 4 inches. This material must be durable such that there is no degradation of the material during and after installation as structural fill. Recycled concrete can be used as trench backfill and pavement base rock if it meets the size requirements for those applications and the requirements for imported granular material. The material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. 4.4.1.4 Trench Backfill Material Trench backfill for the utility pipe base and pipe zone should consist of well -graded, durable, crushed, granular material with a maximum particle size of 3/4 inch and less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve. The material should be free of roots, organic material, and other unsuitable material. Backfill for the pipe base and pipe zone should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D1557, or as recommended by the pipe manufacturer. Within building and other structural areas, trench backfill placed above the pipe zone should consist of imported granular material as specified above. The backfill should be compacted to at least 92 percent of the maximum dry density, as determined by ASTM D1557, at depths greater than 2 feet below the finished subgrade and 95 percent of the maximum dry density, as determined by ASTM D1557, within 2 feet of finished subgrade. In all other areas, trench backfill above the pipe zone should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D1557. 4.4.1.5 Stabilization Material Stabilization material used in stagngor haul road areas or in trenches should consistof 4- or 6 -inch -minus pit -or quarry -run rock, crushed rock, or crushed gravel and sand. The material should have a maximum particle size of 6 inches, should have less than 5 percent by dry weight passingthe U.S. Standard No. 4 sieve, and should have at least two mechanically fractured faces. The material should be free of organic material and other deleterious material. Stabilization material should be placed in lifts between 12 and 24 inches thick and compacted to a well -keyed, firm condition. 4.4.1.6 Aggregate Base Rock Imported granular material used as base rock for building floor slabs and pavement should consist of 3/4 -or 1% -inch -minus material. The aggregate should have less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve and have at least two fractured faces. The aggregate base should be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. 4.4.2 Geotextile Fabric 4.4.2.1 Separate Geotextile Fabric A separation geotextile fabric can be placed as a barrier between silty subgrade and granular material in staging areas, haul road areas, or in areas of repeated construction traffic. The subgrade geotextile should meet the requirements in OSSC 02320 (Geosynthetics) for subgrade geotextiles and be installed in conformance with OSSC 00350 (Geosynthetic Installation). 4.4.2.2 Drainage Geotextile Fabric Drain rock and other granular material used for subsurface drains should be wrapped in a geotextile fabric that meets the specifications provided in OSSC 00350 (Geosynthetic Installation) and OSSC 02320 (Geosynthetics) for drainage geotextiles and installed in conformance with OSSC 00350 (Geosynthetic Installation). 4.4.3 AC The AC should be Level 2, %-inch, dense ACP as described in OSSC 00744 (Asphalt Concrete Pavement) and compacted to 91 percent of the specific gravity of the mix, as determined by ASTM D2041. The minimum and maximum lift thicknesses are 2.0 and 3.0 inches, respectively for %-inch ACP. Asphalt binder should be performance graded and conform to PG 64-22 or better. 4.4.4 CementAmendment 4.4.4.1 General As an alternative to the use of imported granular material for wet weather structural fill, an experienced contractor may be able to amend the on-site soil with portland cement to obtain suitable support properties. Successful use of soil amendment depends on the use of correct mixing techniques, soil moisture content, and amendment quantities. The amount of cement used during amendment should be based on an assumed soil dry unit weight of 100 pcf. 4.4.4.2 Subbase Stabilization Specific recommendations based on exposed site conditions for soil amendment can be provided if necessary. However, for preliminary design purposes, we recommend a target strength for cement -amended subgrade for building and pavement subbase (below aggregate base) be 100 psi. The amount of cement used to achieve this target generally varies with moisture content and soil type. It is difficult to predict field performance of soil to cement amendment due to variability in soil response, and we recommend laboratory testing to confirm expectations. Generally, 5 percent cement by weight of dry soil can be used when the soil moisture content does not exceed approximately 20 percent. If the soil moisture content is in the range of 25 to 35 percent, 6 to 8 percent by weight of dry soil is recommended. The amount of cement added to the soil may need to be adjusted based on field observations and performance. We recommend assuming 6 percent forbidding. Moreover, depending on the time of year and moisture content levels during amendment, water may need to be applied during tilling to appropriately condition the soil moisture content. Amendment depths for building/pavement, haul roads, and staging areas are typically on the order of 12, 16, and 12 inches, respectively. The crushed rock typically becomes contaminated with soil during construction. Contaminated base rock should be removed and replaced with clean rock in pavement areas. The actual thickness of the amended material and imported granular material for haul roads and staging areas will depend on the anticipated traffic, as well as the contractor's means and methods and, accordingy, should be the contractor's responsibility. A minimum curing time of four days is required between amendment and construction traffic access. Construction traffic should not be allowed on unprotected, cement -amended subgrade. To protect the cement -amended surfaces from abrasion or damage, the finished surface should be covered with 4 to 6 inches of imported granular material. Cement amendment should not be attempted during moderate to heavy precipitation. Cement should not be placed when the ground surface is saturated or standing water exists. All mud should be removed from the surface of an amendment area prior to attempting to amend. 4.4.4.3 Cement -Amended Structural Fill On-site soil that would not otherwise be suitable for structural fill may be amended and placed as fill over a subgrade prepared in conformance with the "Site Preparation" section. The cement ratio for general cement -amended fill can generally be reduced by 1 percent (by dry weight). Typically, a minimum cu ri ng of fou r days is required between amend ment and construction traffic access. Consecutive lifts of fill may be amended immediately after the previous lift has been amended and compacted (e.g., the four-day wait period does not apply). However, where the final lift of fill is a building or roadway subgrade, the four-day wait period is in effect for the final lift of cement -amended soil. 4.4.4.4 Other Considerations Cement -amended runoff should be collected, monitored, and treated in accordance with Oregon Department of Environmental Quality requirements prior to being discharged. Portland cement - amended soil is hard and has low permeability. This soil does not drain well and it is not suitable for planting. Future planted areas should not be cement amended, if practical, or accommodations should be made for drainage and planting. Moreover, cement amending soil within building areas must be done carefully to avoid trapping water under floor slabs. We should be contacted if this approach is considered. Cement amendment should not be used if runoff during construction cannot be directed away from adjacent wetlands (if any). Cement amendment should not be attempted unless the air temperature is at least 40 degrees Fahrenheit and rising. 4.5 EROSION CONTROL The on-site soil is susceptible to erosion. Consequently, we recommend that slopes be covered with an appropriate erosion control product if construction occurs during periods of wet weather We recommend that all slope surfaces be planted as soon as practical to minimize erosion. Surface water runoff should be collected and directed away from slopes to prevent water from running down the slope face. Erosion control measures such as straw bales, sediment fences, and temporary detention and settling basins should be used in accordance with local and state ordinances. 4.6 DRAINAGE CONSIDERARONS 4.6.1 Temporary During earthwork at the site, the contractor should be responsible for temporary drainage of surface water as necessary to prevent standing water and/or erosion at the working surface. 4.6.2 Surface The ground surface around the finished building pad should be sloped away from the edge of the pad ata minimum 2 percent gradient for a distance of at least 5 feet. Roof drainage from the structure should be directed into solid, smooth -wall drainage pipes that carry the collected water to the storm drain system. Trapped planter areas should not becreated adjacentto pavement and structures without providing means for positive drainage (e.g., swales or catch basins). Surface and subsurface drainage systems should not be tied to one another, unless special provisions are taken to prevent backflow, of surface water into the subsurface drainage system. 4.6.3 Foundation Drains Provided surface drainage recommendations are met, it is our opinion that perimeter foundation drains are not required for shallow foundations of at -grade buildings. If perimeter foundation drains will be constructed, they should slope at a minimum of approximately % percent and drain by gravity or be pumped to a suitable discharge. The perforated drainpipe should not be tied to a stormwater drainage system without backflow, provisions. The foundation drains should consist of 4 -inch -diameter, perforated drainpipe embedded in a minimum 2 -foot -wide zone of crushed drain rock wrapped in drainage geotextile that extends to within 12 inches of the ground surface. The invert elevation of the drainpipe should be installed at least 18 inches below the elevation of the floor slab. The drain rock and geotextile should meet the requirements specified in the "Materials" section. 4.7 PERMANENT SLOPES Permanent cut and fill slopes should not exceed 2H 1V. Access roads and pavement should be located at least 5 feet from the top of cut and fill slopes. The setback should be increased to 10 feet for buildings. The slopes should be planted with appropriate vegetation to provide protection against erosion as soon as possible after grading. Surface water runoff should be collected and directed away from slopes to prevent water from running down the face of the slope. 6'x01.101110I1L\ 110109-311:1 101:1 5.1 GENERAL Holmes indicates preliminary foundation column loads will be on the order of 60 and 135 kips for live and dead loads, respectively. Based on the provided loads, shallow foundations supported of gravel pads or on soil improvement are suitable to support the proposed development. Explorations at the site indicate dense gravel will be present approximately 10.5 and 13 feet BGS across the site. While gravel pads will provide support for the proposed building, we estimate placing the foundations on aggregate pier ground improvement may be cost effective and will provide a significantly higher bearing capacity. 5.2 SHALLOW FOUNDA BONS ON GRAVEL PADS In our opinion, the structure can be supported on conventional spread footings established on minimum 2 -foot -thick gravel pads underlain by undisturbed native soil. Gravel pads should be supported on firm, undisturbed native soil or structural fill. The gravel pads should extend 1 foot beyond the margns of the footings for every 2 feet excavated below the base grade of the footings. Gravel pads should consist of imported granular material compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557, or until well keyed, as determined by one of our geotechnical staff. 5.2.1 Bearing Capacity Foundations bearingon 2 -foot -thick gravel pads can be proportioned for a maximum allowable bearing pressure of 3,000 psf. This bearing pressure is a net bearing pressure and applies to the total of dead and long-term live loads and may be doubled when considering seismic or wind loads. The weight of the footingand any overlying backfill can be ignored when calculating footing loads. We recommend that isolated column and continuous wall footings have minimum widths of 24 and 18 inches, respectively. The bottom of exterior footings should be founded at least 18 inches below the Iowestadjacent grade. Interior footings should be founded at least 12 inches below the top of the floor slab. The recommended minimum footing depth is greater than the anticipated frost depth. Based on our analysis and experience with similar soil, total post -construction consolidation - induced settlement should be less than 1 inch, with differential settlement less than one-half over a 50 -foot span. 5.3 SHALLOW FOUNDA BONS ON AGGREGATE PIER GROUND IMPROVEMENT Asan alternate to supporting foundations on granular pads, foundations can be supported on soil improved using aggregate piers extend ing down to the underlying dense to very dense gravel encountered at depths between 10.5 and 13 feet BGS. Considering the proposed foundation loads and depths to gravel, aggregate piers are anticipated to be the most economical ground improvement option. Aggregate piers are a ground improvement system that consists of installing compacted aggregate piers that reinforce and improve the soil. In general, aggregate pier foundations consist of 2 -to 3 -foot -diameter drilled holes backfilled with compacted crushed rock. The crushed rock is placed in the hole in lifts and compacted. Piers are typically arranged in a grid pattern to provide uniform support for foundations. These systems are proprietary and designed and constructed by specialty contractors. If used, aggregate piers will be installed below groundwater and casing will likely be required to advance the auger excavations for the aggregate piers. As an alternative, displacement aggregate piers could be used. An allowable bearing pressure between 5,000 and 7,000 psf is typically provided by the designers of aggregate piers. A one-third increase in allowable bearing pressure is also typical for such systems when resisting short-term loads such as wind and seismic forces. We recommend the specialty contractor obtain the structural loads and settlement requirements from the project structural engineer and use this information to design the aggregate piers. The contractor can use the information in this report and, if necessary, should conduct additional explorations if the geotechnical information is insufficient. 5.4 LATERAL RESISTANCE Lateral loads on footings can be resisted by passive earth pressure on the sides of the structure and by friction on the base of the footings. Our analysis indicates that the available passive earth pressure for footings confined by structural fill or footings constructed in direct contact with the undisturbed native soil or structural fill is 325 pcf. Typically, the movement required to develop the available passive resistance may be relatively large; therefore, we recommend using a reduced passive pressure of 250 pcf equivalent fluid pressure. Adjacent floor slabs, pavement, or the upper 12 -inch depth of adjacent, unpaved areas should not be considered when calculating passive resistance. In addition, in order to rely on the recommended passive resistance, the groundwater level must be below the base of the footing and a minimum of 5 feet of horizontal clearance must exist between the face of the footings and any adjacent downslopes. The "Foundation Drains' section provides recommendations to maintain groundwater levels that are below the foundations. A friction coefficient of 0.40 can be used for footings established on granular pads or a crushed rock leveling course for aggregate piers. 5.5 CONSTRUCTION CONSIDERA BONS NV5 should evaluate all foundation subgrades duringconstruction to confirm removal of unsuitable soil and that the subgrade is consistent with the conditions observed in our explorations. If over -excavation is necessary, the unsuitable material should be replaced with compacted crushed rock. 6.0 FLOOR SLABS Floor slabs should be established on a subgrade that has been prepared in accordance with the "Site Preparation" section. A minimum 6 -inch -thick layer of imported compacted granular material should be placed over the prepared subgrade to assistas a capillary break. Imported granular material should meetthe requirements for aggregate base rock in the "Materials" section. The imported granular material should be placed in one lift and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. Slabs should be reinforced according to their proposed use and per the structural engneer's recommendations. Load-bearing concrete slabs maybe designed assuming modulus of subgrade reaction, k, of 125 psi per inch, provided the subgrade is prepared in accordance with the "Site Preparation" section. Vapor barriers beneath floor slabs are typically required by flooring manufactures to maintain the warranty on their products. In our experience, adequate performance of floor adhesives can be achieved by using a clean base rock (less than 5 percent fines) beneath the floor slab with no vapor barrier. In fact, vapor barriers can frequently cause moisture problems by trapping water beneath the floor slab that is introduced during construction. If a vapor barrier is used, water should not be applied to the base rock prior to pouring the slab and the work should be completed during extended dry weather so that rainfall is not trapped on top of the vapor barrier. Selection and design of an appropriate vapor barrier, if needed, should be based on discussions among members of the design team. We can provide additional information to assist you with your decision. 7.0 RETAINING STRUCTURES Our retaining wall design recommendations are based on the following assumptions: (1) the walls consist of conventional, cantilevered retaining walls, (2) the walls are less than 8 feet in height, (3) the backfill is drained, and (4) the retained soil has a slope flatter than 4H:1V. Re- evaluation of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. 7.1 WALL DESIGN PARAMETERS For unrestrained retaining walls, an active equivalent fluid pressure of 35 pcf should be used for design. Where retai ning walls (such as basement stem walls) are restrained from rotation prior to being backf lled, an equivalent fluid pressure of 55 pcf should be used for design. Provided walls can yield a small amount from seismic loading, a superimposed seismic lateral force should be calculated based on a dynamic force of 7 H2 pounds per lineal foot of wall, where H is the height of the wall in feet, and applied at 0.6H from the base of the wall. If surcharges (e.g., slopes steeper than 4H:1V, foundations, vehicles, etc.) are located within a horizontal distance from the back of a wall equal to twice the height of the wall, additional pressures may need to be accounted for in the wall design. Our office should be contacted for appropriatewa II surcharges based on the actual magnitude and configuration of the applied loads. The wall footings should be designed in accordance with the recommendations in the "Foundation Support" section. IF1•:7.111 X1:7• IIJG [HL• IJUI a• [N:1 ]III The above design parameters have been provided assumingthat back -of -wall drains will be installed to prevent buildup of hydrostatic pressures behind all walls. If a drainage system is not installed, our office should be contacted for revised design forces. A minimum 6 -inch -diameter, perforated collector pipe should be placed at the base of the walls. The pipe should be embedded in a minimum 2 -foot -wide zone of angular drain rock that is wrapped in a drainage geotextile fabric and extends up the back of the wall to within 1 foot of the finished grade. The drain rock and drainage geotextile fabric should meet specifications provided in the "Materials" section. The perforated collector pipes should discharge at an appropriate location away from the base of the wall. The discharge pipe(s) should not be tied directly into stormwater drain systems, unless measures are taken to prevent backflow, into the drainage system of the wall. Backfill material placed behind the walls and extendinga horizontal distance of %H, where H is the height of the retainingwall, should consist of retainingwall select backfill placed and compacted in conformance with the "Materials" section. 7.3 RETAINING WALL BACKFILL Backfill should be placed and compacted as recommended for structural fill, with the exception of backfill placed immediately adjacent to walls. Backfill adjacent to walls should be compacted to a lesser standard to reduce the potential for generation of excessive pressure on the walls. Backfill located within a horizontal distance of 3 feet from retaining walls should be compacted to approximately 90 percent of the maximum dry density, as determined by ASTM D1557. Backfill placed within 3 feet of the wall should be compacted in lifts less than 6 inches thick using hand -operated tamping equipment (such as a jumping jack or vibratory plate compactor). If flatwork (slabs, sidewalk, or pavement) will be placed adjacent to the wall, we recommend the upper 2 feet of fill be compacted to 95 percent of the maximum dry density, as determined by ASTM D1557. Settlement of up to 1 percent of the wall height commonly occurs immediately adjacentto the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend that construction of flatwork adjacent to retaining walls be postponed at least four weeks after backfilling of the wall, unless survey data indicates that settlement is complete prior to that time. 8.0 PAVEMENT Pavement subgrade should be prepared in accordance with the "Site Preparation" section. Our pavement recommendations are based on the following assumptions: • The top 12 inches of soil subgrade below the pavement section are compacted to at least 92 percent of its maximum density, per ASTM D1557, or observations indicate that it is in a firm, unyielding condition. • Resilient moduli of 3,500 psi and 20,000 psi were estimated for the prepared subgrade and base rock, respectively. • Initial and terminal serviceability indices of 4.2 and 2.0, respectively. • Reliability of 75 percent and standard deviation of 0.45. • Structural coefficients of 0.42 and 0.10 for the AC and aggregate base, respectively. • A 20 -year design life with no planned growth. • Heavy traffic generally consists of occasional garbage trucks and maintenance trucks. • Traffic loading as follows: • Parking lot stalls (passenger vehicle parking only) • Light duty (access roads for parking lots with occasional garbage truck or similar) If any of these assumptions are incorrect, our office should be contacted with the appropriate information so that the pavement designs can be revised. Our recommendations are provided in Table 1. Table 1. Minimum Pavement Thicknesses with Compacted Soil Subgrade Traffic Loading Light Duty Pavement Section Thicknesses Pavement Section Thicknesses on On -Site Subgradei on Cement -Amended AC I Aggregate Base I AC I Aggregate Base 3.0 1 9.0 1 3.0 1 4.0 1. All thicknesses are intended to be the minimum acceptable values. 2. compressive strength of cement -amended soil should beat least 100 psi. All of the recommended pavement sections with subgrades prepared as recommended are suitable to support an occasional 75,000 -pound fire truck. The AC and aggregate base should meet the requirements outlined in the "Materials" section. Our design assumes that construction will be completed during an extended period of dry weather and with subgrade soil prepared as described in this report. Wet weather construction may require an increased thickness of aggregate base. The pavement sections recommended above are designed to support post -construction traffic. Heavy construction traffic should not be allowed on prepared subgrade or new pavement but kept on haul roads or non-structural areas. If construction traffic is allowed on new pavement, allowance for the additional loading and wear should be included in the design section. 9.0 SEISMIC DESIGN PARAMETERS A site-specific seismic hazard evaluation was completed for the project. The results of the study and seismic design parameters for the project are presented in Appendix C. 10.0 OBSERVATION OF CONSTRUCTION Satisfactory foundation and earthwork performance depends to a large degree on quality of construction. Sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. Subsurface conditions observed during construction should be compared with those encountered during the subsurface exploration. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect if subsurface conditions change significantly from those anticipated. We recommend that NV5 be retained to observe earthwork activities. We anticipate that this will consist of evaluating footing, floor slab, sidewalk, and pavement subgrade; observing the placement of structural fill: evaluating su bgrade repairs; observing ground improvement; testing trench backfill; and performing laboratory compaction and field moisture-density tests. 11.0 LIMITATIONS We have prepared this report for use by Northwest Sustainable Properties and members of their design and construction team for the proposed project. The data and report can be used for bidding or estimating purposes, but our report, conclusions, and interpretations should not be construed as warranty of the subsurface conditions and are not applicable to other sites. Exploration observations indicate soil conditions only at specific locations and only to the depths penetrated. They do not necessarily reflect soil strata or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during the course of excavation and construction, reevaluation will be necessary. The site development plans and design details were preliminary at the time this report was prepared. When the design has been finalized and if there are changes in the site grades or location, configuration, design loads, or type of construction, the conclusions and recommendations presented may not be applicable. If design changes are made, we request that we be retained to review our conclusions and recommendations and to provide a written modification or verification. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in this report for consideration in design. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with generally accepted practices in this area at the time this report was prepared. No warranty, express or implied, should be understood. We appreciate the opportunity to be of continued service to you. Please call if you have questions concerning this report or if we can provide additional services. Sincerely, NV5 Tyler A Pierce, P.E. Project Engineers f awn I Dimke, P.E.. G.E. Principal Engneer FIGURES �r Hayden BridgeRd�' - nr NASI ■� -QS - -t �m �► Pw C` �eAIlk gnia Blvd _ �� �� W e� , _I ,Center) a, Bid — - 11 �r-• \ r�`rr aft 225:-', )N AERIAL i ED FROM I I )I I I 1 I I 1 I I I I B-4 0 (13) 1 I 5 I ;) 1 I I I I I 1 LEGEND: ---- PROJECT LIMITS 6-1 0 BORING (10.5) GRAVELDEPTH To DENSE ERE ENCOUNTERED (FEET GS) Re Mi ARRAY LOCATION `tom 0 40 80 (SCALE IN FEET) SITE PLAN BASED ON AERIAL PHOTOGRAPH OBTAINED FROM GOGGLE EARTH PRO-, JULY 7, 2021 ry z z APPENDIX A APPENDIX A FIELD EXPLORATIONS GENERAL The site was explored by drilling six borings (B-1 through B-6) on June 9 and 10, 2021 to depths between 11.5 and 39 feet BGS. Drillingservices were provided by Western States Soil Conservation, Inc. of Hubbard, Oregon. Figure 2 shows the approximate exploration locations. The exploration locations were determined by pacingfrom existingsite features should be accurate implied by the methods used. The explorations were observed a member of NV5's staff. The exploration logs are presented in this appendix. SOIL SAMPLING We collected representative samples of the various soils encountered during drilling for geotechnical laboratory testing. Samples were collected from the borings using 1;42- or 3 -inch - inside diameter split -spoon samplers (SPT) in general accordance with ASTM D1586. The sampler was driven into the soil with a 140 -pound automatic trip hammer free -falling 30 inches. The sampler was driven a total distance of 18 inches. The number of blows required to drive the sampler the final 12 inches is recorded on the exploration logs, unless otherwise noted. Relatively undisturbed samples were collected using standard Shelby tube in general accordance with ASTM D1587. Sampling methods and intervals are shown on the exploration logs. The average efficiency of the automatic SPT hammer used by Western States Soil Conservation, Inc. was 87.4 percent. The calibration testing results are presented at the end of this appendix. The soil samples were classified in accordance with the "Exploration Key" (Table A-1) and "Soil Classification System" (Table A-2), which are presented in this appendix. The exploration logs indicate the depths at which the soil or its characteristics change, although the change actually could be gradual. If the change occurred between sample locations, the depth was interpreted Classifications are shown on the exploration logs. WM:D1.0 01:\A 119110 [ . CLASSIFICARON The soil samples were classified in the laboratory to confirm field classifications. The laboratory classifications are shown on the exploration logs if those classifications differed from the field classifications. ATIERBERG LIMIIS The plastic limit and liquid limit (Atterberg limits) of select soil samples were determined in general accordance with ASTM D4318. The test results are presented in this appendix. CONSOLIDATION Consolidation testing was performed on a select soil sample in general accordance with ASTM D2435. The test measures the volume change of a soil sample under predetermined loads. The test results are presented in this appendix. DRYDENSITY We tested the in situ dry density of a select soil sample in general accordance with ASTM D2937. The dry density of the ratio between the mass of the soil (not including water) and the volume of the intact sample. The density is expressed in units of pcf. The test results are presented in this appendix. MOISTURE CONTENT We tested the natural moisture content of select soil samples in general accordance with ASTM D2216. The test results are presented in this appendix. PARRCLE-SIZE ANALYSIS We completed particle -size analysis on select soil samples in order to determine the particle -size distribution in general accordance with ASTM D1140. The test results are presented in this appendix. SYMBOL SAMPLING DESCRIPTION Location of sample collected in general accordance with ASTM D1586 using Standard Penetration Test (SPT) with recovery Location of sample collected usingthin-wall Shelby tube or Geoprobe® sampler in general accordance with ASTM D1587 with recovery Location of sample collected using Dames & Moore sampler and 300-pound hammer or pushed with recovery Location of sample collected using Dames & Moore sampler and 140-pound hammer or pushed with recovery Location of sample collected using 3-inch-outside diameter California split-spoon sampler and 140-pound hammer with recovery Location of grab sample Graphic Log of Soil and Rock Types observed contact between soil or f rock units (at depth indicated) ' Rock Coring interval Water level duringdrilling Inferred contact between soil or rock units(atapproximate depths z 1 indicated) Water level taken on date shown GEOTECHNICAL TESTING EXPLANATIONS ATT Atterberg Limits P Pushed Sample CBR California Bearing Ratio PP Pocket Penetrometer CON Consolidation P200 Percent Passing U.S. Standard No. 200 DD Dry Density Sieve DS Direct Shear RES Resilient Modulus HYD Hydrometer Gradation SIEV Sieve Gradation MC Moisture Content TOR Torvane MD Moisture-Density Relationship UC Unconfined Compressive Strength NP Non -Plastic VS Vane Shear OC Organic Content kPa Kilopascal ENVIRONMENTAL TESTING EXPLANATIONS CA Sample Submitted for Chemical Analysis NO Not Detected P Pushed Sample NS No Visible Sheen PID Photoionization Detector Headspace SS Slight Sheen Analysis MS Moderate Sheen PPM per Million HS Heavy Sheen 1'JPartrts NY EXPLORATION KEY TABLEA-1 RELATIVE DENSITY -COARSE-GRAINED SOIL Relative Density Standard Penetration Test (SPT) Resistance Dames & Moore Sampler (140 -pound hammer) Dames & Moore Sampler (300 -pound hammer) very loose 0-4 0-11 0-4 Loose 4-10 11-26 4-10 Medium dense 10-30 26-74 10-30 Dense 30-50 74 - 120 30 -47 very dense More than 50 More than 120 More than 47 CONSISTENCY- FINE-GRAINED SOIL Standard Consistency Penetration Test SPT Resistance Dames &Moore Sampler (140 -pound hammer Dames &Moore Unconfined Sampler Compressive Strength (300 -pound hammer Old) Very soft Less than Less th a n 3 Less than Less than 0.25 Soft 2-4 3-6 2-5 0.25-0.50 Medium stiff 4-8 6-12 5-9 0.50-1.0 Stiff 8-15 12-25 9-19 1.0-2.0 Verystiff 15-30 25-65 19-31 2.0-4.0 Hard More than 30 More than 65 More than 31 More than 4.0 PRIMARY SOIL DIVISIONS GROUPSYMBOL GROUP NAME COARSE- GRAINED SOIL GRAVEL (more than 50% of coarse fraction retained On No.4sieve) CLEAN GRAVEL (<5%fines) GW or GP GRAVEL GRAVEL WITH FINES (>>5%and <12%fines) GW -GM or GP -GM GRAVEL with silt GW -GC or GP -GC GRAVEL with clay GRAVELWITH FINES (>12%fines) GM silty GRAVEL GO clayey GRAVEL GC -GM silty, clayey GRAVEL (more than 50% retained on N0. 200 sieve) SAND (50% or more of coarse fraction passing N0. 4sieve) CLEAN SAND (<5%fines) SW or SP SAND SAND WITH FINES (>5%and <12%fines) SW-SMOr SP -SM SAND with silt SWSCor SPSOSAND with clay SAND WITH FINES (>12%fines) SM si lty SAND SC clayey SAND SC -SM silty, clayey SAND FINE-GRAINED SOIL (50% or more passing N0. 200 sieve) SI LT AND CLAY Liquid limit less than 50 ML SILT CL CLAY CL -ML silty CLAY OL ORGANIC SILT or ORGANIC CLAY Liq uid limit 500r greater MHSILT CH CLAY OH ORGANIC SILT or ORGANIC CLAY HIGHLY ORGANIC SOIL PT PEAT MOISTURE CLASSIFICATION ADDITIONAL CONSTITUENTS Term Field Test Secondary granular components or other materials such as organics, man-made debris, etc. Percent Silt and Clay In: Percent Sand and Gravel In: dry very low moisture, dry to touch Fine- Coarse- Grained Soil Grained Soil Fine- Coarse - Grained Soil Grained Soil moist damp, without visible moisture <5 trace trace <5 trace trace 5 - 12 minor with 5- 15 minor minor visible free water, >12 some silty/clayey 15-30 wet usually saturated >30 NY J SOIL CLASSIFICATION SYSTEM with with sandy/gravelly Indicate% TABLE A-2 DEPTH FEET .o U g 2 L1 MATERIAL DESCRIPTION O FF Qd ? ,J w w ❑ NZ w ~ J D. Q N ♦BLOW COUNT • MOISTURE CONTENT% ® RQD% ® CORE REC% 0 s0 100 INSTALLATION AND COMMENTS ASPHALT CONCRETE (2.0 inches). Oz Dense. gray GRAVEL with sand (GW); dry (base rack). z.s ' Loose, dark brown, silty SAND with organics (SM); dry .moist, organics xa are roots-FlLL. PP �'. ♦ w -leer Medium stiff, gray with brown mottled CLAY (Ch), trace sand; moist, clay has s.o high plasticity. soft at 5.0 feet PP W -Os er 7.s soft to medium stiff at 7.5 feet PP PP-1Oer a'', 10.0 as 105 PP w-los er Medium dense, gray, silty SAND (SM); wet, sand is fine. ♦ Yl Very dense, gray GRAVEL with silt and 12.5 ,sand (GP-GMYwet ns surface elevation was not the a:ne a -plitcaacn_ Exploration completed at a depth ofuaaav 11.5 feet Hammer efficiency factor is 87.4 percent 1 s.0 17.s z0.o zz.s zs.0 27.s 30.0 0 al 100 DRILLED IN: WaI 9a¢ Sal Cmuwatim, Inc LOGGED PI: CDMPLETED: 0811021 PDRING.17.D:.—carauga(a Emmmllan BORING BIT DIAMETER: 41MIrcIo Ol'i BORING B-1 N 5 kmpju,-,FY 2021 A STREET MIXED-USE PROJECT SPRINGFIELD, OR FIGURE A-1 DEPTH FEET .o U g 2 L1 MATERIAL DESCRIPTION O FF Qd ? ,J w w ❑ Z u, w ~ J D. Q N ♦BLOW COUNT • MOISTURE CONTENT% ® ROM ® CORE REC% 0 50 100 INSTALLATION AND COMMENTS ASPHALT CONCRETE (2.0 inches). Dense, gray GRAVEL with sand (GW); dry, gravel is angular(base rock). 0.7 Medium stiff, orange -gray CLAY (CH), 2.5 trace sand; moist, clay has high plasticity. PP 5.0 gray with orange mottles at 5.0 feet PT -0.)S er PP 7'5 gray with dark gray mottles at 7.5 feet PP 10.0 las PP Y' T-lser Stiff, gray with orange mottled, sandy CLAY (CL); moist to wet, sand is fine. 12.5 Exploration completed at a depth of 11.5 feet 11's SorfaCe levatan� q of -pl.cat— Hammer efficiency factor is 87.4 percent 15.0- 5.0n.520.022.525.027.s 17.5- 20.0- 22.5- 25.0- 27.5 30.0 0 so 100 DRILLED IN: We4em 9a¢ Sal Cmuwatim, Inc LOGGED BY CDMPLETED: 0811021 PDRING.17.D:.—accan,er' eEmmlat.) BORING BIT DIAMETER: 41MIrcIo BORING B-2 N 5 kmjup,-FOP-2�01 Y 2021 A STREET MIXED-USE PROJECT SPRINGFIELD, OR FIGURE A-2 O J ♦BLOW COUNT INSTALLATION AND DEPTH U MATERIAL DESCRIPTION FF Z COMMENTS FEET g ,J ❑ w Q ® RQD% ® CORE REC% 2 L1 w ~ N 0 s0 100 '0 ASPHALT CONCRETE (3.0 inches). 03 Denseracgray GRAVEL with sand(GW); dry (baBe k). 09 '.. can eewl:I: eaumer simc Medium dense, gray, silty GRAVEL with 2.5 debris (GM); dry to moist, debris is rB wood and concrete - FILL. Medium stiff, gray with dark gray 5.0 mottled CLAY (CH), trace sand and organics; moist, clay has high plasticity. PP - a ].s • � W Os 6r PP I 10.0 gray with orange mottles at 10.5 feet PP �''. • w-Tzs er 13.5 Y Dense to very dense, gray GRAVEL with 13O sand (GP); wet, gravel is fine to coarse, a - sand is fine to coarse. Iso Is s mesa ele wss Dov Exploration completed at a depth of 16.5 feel the tins, a e:oio�aimetroe Hammer efficiency factor is 87.4 percent z0.o zz.s zs.0 v.s 30.0 0 W 100 DRILLED BY:Wtlem 9e¢ s" Cm—s-r'- LOGGED BY: mMPLETED: 0L1021 .RINLMEf.D Mauskm wga (seeemmmllan BORING BIT DIAMETER: 41MIrcIo NWSPROP2 1 BORING B-3 N 5 JULY 2021 A STREET MIXED-USE PROJECT FIGURE A-3 SPRINGFIELD, OR DEPTH FEET '0 U g MATERIAL DESCRIPTION 2 V O FF Qd ? ,J w w ❑ u,Z w ~ J Q N ♦BLOW COUNT • MOISTURE CONTENT% ® RQD% ® CORE REC% 0 50 100 INSTALLATION AND COMMENTS ASPHALT CONCRETE (3.0 inches). 03 OIL MAT (2.0 inches). z.s Oe ATT'., PP_lsbr R_30M CRUSHED ROCK (base rock; 3.0 inches). Medium stiff, brown with gray mottled CLAY (CH), trace sand; moist, sand is fine, clay has high plasticity. '., 5.0 very soft; wet at 4.5 feet Shelby ree rtan 1 fou crRed.4chenll Co. : feet O haring ats feet 10.0 gray with brown mottles, with sand; moist to wet at 9.0 at PP °: ♦I : : PIP _1Os by 12.5 1s° Medium dense, gray, silty GRAVEL with sand (GM); wet, gravel is fine to coarse, sand is fine to coarse. so 17.5— sDense, 100 Meavy am �g axatter at Dense,gray GRAVEL with silt and sand (GP -GM); wet, gravel is fine. iso feet. zo.o - Q o gs : : : : : : : S.—e elavaeon evas aot Exploration completedatadepth of 22.5— 21.5 feet : : : : : : : e%oiorat- the brat a Hammer efficiency factor is 87.4 percent 25.0 — 27.5 30.0 0 w 100 DRILLED PI:Wtlem 9e¢ sal C—ybm,Mc LOGGED PI: COMPLETED: B�10R1 BORINGIAUI O: mitl rdaylurtlaunenl htl) BORING BIT DIAMETER: 4T81axa e NWSPROP-2-01 BORING B-4 N 5 JULY 2021 A STREET MIXEI>USE PROJECT SPRINGFIELD, OR FIGURE A-4 O ♦BLOW COUNT INSTALLATION AND DEPTH U FF Qd J • MOISTURE CONTENT% COMMENTS FEET g MATERIAL DESCRIPTION ? w u,Z D. ,J ❑ w Q ® RQD% ® CORE REC% 2 Ly w ~ N 0 s0 100 '0 ASPHALT CONCRETE (3.5 inches). 03 Dense. gray GRAVEL (GP): dry. gravel is angular (base rack). 10 Medium stiff, red -brown CLAY (CH); 2.5 moist to wet, clay has high plasticity. PP w-lser 5.0 soft at 5.0 feet 1 w -0s er PP medium stiff at 8.0 feet PP y I V I I I LL�fiO% 10.0 ATT 12.5 Dense to very dense, dark gray GRAVEL with silt and sand (GP -GM); wet, gravel a is fine to coarse and subrounded. Iso O s0 Pd0012% O 1].5 very dense, with cobbles; cobbles are ''. 10 approximately 15% at 18.0 feet DNII rig chatter a 1 so feet o.o Switch to32/O-ncM1 bit at NI O rest. 22.5 27.5- 0 0 so 100 DRILLED B'l:Wtlem 9il¢ s"Cmuwatim,lnc LOGGED PI: mMPLETED:�6'RI PoRINLMUIpD: m d NaylordwertwlhtlBORING RING BIT DIAMETER: OTM1sM M BIrca371sinB MNSPROp2 1 BORING B-5 N 5 JULY 2021 A STREET MIXED-USE PROJECT FIGURE A-5 SPRINGFIELD, OR DEPTH FEET 0.0 U g 2 Ly MATERIAL DESCRIPTION O FF Qd ? ,.J w w ❑ Z N w ~ J Q N ♦BLOW COUNT • MOISTURE CONTENT% ® RQD% ® CORE REC% 0 50 100 INSTALLATION AND COMMENTS o (continued from previous page) 32.5 o 35.0 3 s PeBB � • m aoo-s% Bsa surface elevation aao not Exploration completed at a depth of 40.0— 39.0 feet axPiauz[ aat roe mne or Hammer efficiency factor is 87.4 percent 42.5- 2.s45.0azs50.052.5ss.0ns60.0 45.0- 47.5- 50.0- 52.5- 55.0- 57.5- 60.0— 0S0 100 LIRILLEG Pl: We4em 9Da s""an—a-Jna LOGGED BY mMPLETED:�d'RI WRINGMUIC ID mitl Maylurtlaunenl htl) BORING BIT DIAMETER: 4WSIWI—a 37MInotm NWSPROP2 t BORING B-5 N 5 (continued) JULY 2021 A STREET MIXEI>USEPROJECT SPRINGFIELD, OR FIGURE A-5 O J ♦BLOW COUNT INSTALLATION AND DEPTH U MATERIAL DESCRIPTION FF Qd ? w u,Z D. • MOISTURE CONTENT% COMMENTS FEET g ,J ❑ w Q ® ROM ® CORE REC% 2 Ly w ~ N 0 sa 100 '0 ASPHALT CONCRETE (8.0 inches). Soft ro medium stiff, red-brown CLAY °' (CH), trace sand; moist to wet, clay has high plasticity. z.s s A w-Osef PP Do-n of 5.0 DO soft at 6.0 feet a 7.5- .s10.0 10.0— medium stiff, gray with dark gray '., '., mottles, minorsand; moist at 10.0 feet PP s, ♦'', '', '', _ °' 09 of lz.s 125 Dense, gray GRAVELwith silt and sand (GP-GM); wet, gravel is fine to coarse and subrounded. 15.0— b. • �' 17.s very dense, with cobbles; cobbles are approximately 15% at 18.0 feet zoo � Yl 21S Exploration eompletedatadepth of 21.5 feet racmueat the e:oin�aimev roe ame a zzs Hammer efficiency factor is 87.4 percent 25.0- s.0vs30.0 27.5- 30.0 0 s° 100 DRILLED V: Weelem 9a¢ Sal Cmuwatim, Inc. LOGGED BY mMPLETEo: ILMI PoRINSMUIC ID mitl Maylurtlaunenl htl) BORING BIT DIAMETER: 4SSIncea MNSPROp2 1 BORING B-6 N 5 JULY 2021 A STREET MIXED-USE PROJECT FIGURE A-6 SPRINGFIELD, OR 60 50 CH rOH • "A" LINE m CL or L MH rOH 40 w ML r OL CL -ML z Y H V 30 H 5 a 20 10 0 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT G RD, EXPLORATION ON SAMPLE DEPTH MOISTURE CONTENT LIQUID LIMIT PLASTIC LIMIT PLASTICITYINDEX 3 NUMBER (FEET) (PERCENT) • 6-4 2.5 37 71 30 41 m 6-5 9.0 49 68 31 37 s b °o 9 d O Z NN/SPROR2-01 ATTERBERG LIMITS TEST RESULTS N V N5 5 ■ JULY 2021 ASTREET MWED-USE PROJECT FIGUREA-7 SPRINGFIELD, OR • m CL or L MH rOH ML r OL CL -ML 2 -4 5.0 51 70 4 6 H 6 z w U N w a 10 z_ 12 14 16 18 G 20 00 1,000 10,000 100,000 a STRESS (PSF) 4 s KEY SAMPLE DEPTH MOISTURE CONTENT DRY DENSITY n °o NUMBER (FEET) (PERCENT) (PCF) • 9 9 d O 1 N PROP-2-01 CONSOLIDATION TEST RESULTS � V1 9 JULY 2021 A STREET MWED-USE PROJECT FIGURE A-8 V SPRINGFIELD, OR -4 5.0 51 70 SAMPLE INFORMATION MOISTURE CONTENT (PERCENT) DRY DENSITY (PCF) SIEVE ATTERBERC LIMITS EXPLORATION NUMBER SAMPLE DEPTH (FEET) ELEVATION (FEET) GRAVEL (PERCENT) SAND (PERCENT) P200 (PERCENT) LIQUID LIMIT PLASTIC LIMIT PLASTIOTY INDEX B-1 2.5 36 B-1 7.5 44 9-1 10.8 10 B-2 2.5 42 B-2 7.5 44 B-2 10.0 45 B-3 7.5 43 B-3 10.0 46 B-3 15.0 11 B3 2.5 37 TI 30 41 94 5.0 51 TO B-4 7.0 44 B-5 2.5 41 B-5 5.0 51 9-5 9.0 49 68 31 37 9-5 15.0 IS 12 9-5 25.0 11 9-5 37.5 13 9 B6 4.0 40 TT B6 10.0 48 B6 15.0 11 B6 20.0 10 N N PROP-2-01 SUMMARY OF LABORATORY DATA JULY 2021 ASTREET MIXED-USE PROJECT SPRINGFIELD, OR FIGURE A-9 Pile Dynamics, Inc. SPT Analyzer Reams Summary of SPT Test Results RIG N PDAS Var. 2018.30 - Pmled: 4/15/2020 Project: WSSO-8-05, Test Dale: 4/13120211 308.02 87.4 Standard Deviation: 4.49 FMX Maximum Energy Overall Maximum Value: 313.51 89.8 ETR: Energy Transfer Raw - Rem Sled Final N HIM Average Average DMth DMth Value Value FMX ETR fl fl 1141, % 42.50 49.00 18 26 308.23 87.5 45.00 48.50 17 24 304.53 87.0 50.00 51.50 12 17 305.90 87.4 52.50 54.00 28 37 308.91 8].] Overd l Average Val ues: 308.02 87.4 Standard Deviation: 4.49 1.3 Overall Maximum Value: 313.51 89.8 Overall Minimum Value: 294.12 84.0 APPENDIX B APPENDIX B C1VAlI ILTRV17:1 V, I F-11 01 F, I IM K The report summarizingthe results of the shear wave ReMi analysis is presented in this appendix. ReMi testingwas completed by Earth Dynamics LLC of Portland, Oregon, on June 10, 2021. The location of the ReMi array is shown on Figure 2. Report on Shear Wave Refraction Microtremor Analysis (ReMi) 702 N A Street Springfield, Oregon Report Date: June 14, 2021 Prepared for: NV5 703 Broadway St. STE 650 Vancouver, WA 98660 Prepared by: EARTH DYNAMICS LLC 2284 N.W. Thurman St. Portland, OR 97210 (503) 227-7659 Project No. 21204 1.0 INTRODUCTION NV5 engaged Earth Dynamics LLC to conduct geophysical explorations at 702 N A Street in Springfield, Oregon. This study was requested and authorized by Mr. Shawn Dimke of NV5. The geophysical field work was completed by Mr. Daniel Lauer of Earth Dynamics LLC on June 10, 2021. This report describes the methodology and results of the geophysical investigation. 2.0 SCOPE OF WORK The purpose of this study is to characterize the subsurface shear wave velocity at the site. These data are needed to help determine the seismic response of the site to earthquake loading. The exploration consisted of one twenty-four channel refraction microtremor (ReMi) array. 3.0 METHOD The ReMi technique provides a simplified characterization of relatively large volumes of the subsurface. The method can be used to estimate one-dimensional shear wave velocity profiles and provide site-specific soil classification data as described in ASCE/SEI 7-16 (2017). In a ReMi survey, geophones are deployed at designated intervals along a linear array. The resolution and depth of investigation depends upon the geophone cut-off frequency, spacing of the geophones, the total array length and the frequency characteristics of the Rayleigh waves at the site. For "rule of thumb" survey planning, the nominal depth of investigation is assumed to be approximately one-third of the geophone array length. The theoretical basis of the ReMi method is the same as Spectral Analysis of Surface Waves (SASW) and Multi -channel Analysis of Surface Waves (MASW) as first described to the earthquake engineering community by Nazarian and Stokoe (1984). However, ReMi does not require a frequency -controlled source and the field equipment is much more compact and economical. A complete description of the theoretical basis for ReMi is described by Louie (2001). In ReMi analysis all interpretation is done in the frequency domain, and the method assumes that the most energetic arrivals recorded are Rayleigh waves. By applying a time -domain velocity analysis, Rayleigh waves can be separated from body waves, air waves, and other coherent noise. Transforming the time -domain velocity results into the frequency domain allows combination of many arrivals over a long time period, and yields easy recognition of dispersive surface waves. EARTH DYNAMICS Spnngfleld Re Mi Study Paye 1 LLC 6/74121 Data reduction is completed in two steps. First, the time versus amplitude seismic records are transformed into spectral energy shear wave frequency versus shear wave velocity (or slowness). The data are graphically presented in what is commonly termed a p -f plot. The interpreter determines a dispersion curve from the p -f plot by selecting the lower bound of the spectral energy shear wave velocity versus frequency trend. The second phase of the analysis consists of fitting the measured dispersion curve with a theoretical dispersion curve that is based upon a model of multiple layers with various shear wave velocities. The model velocities and layer thicknesses are adjusted until a 'best fit' to the measured data is obtained. This type of interpretation does not provide a unique model. Interpreter experience and knowledge of the existing geology is important to provide a realistic solution. The data are presented as one-dimensional velocity profiles that represent the average shear wave velocities of the subsurface layers over the length of the geophone array. For this project, data were acquired for one ReMi array. The ReMi array consists of twenty-four 4.5 Hz vertical geophones mounted on the asphalt parking lot surface. The array was installed using a geophone spacing of thirteen feet and the total array length is 299 feet. More than forty 30 -second long seismic records of ambient seismic noise were recorded for the array. Data were also acquired when vehicles, and people were moving on and near the site. 4.0 RESULTS The approximate location of the ReMi array is shown on the Google Earth image contained in Figure 4-1. The ReMi analysis and results for ReMi Array 1 are contained in Figure 4-2. Figure 4-2 contains the p -f plot, the dispersion curve, the derived velocity versus depth model that best fits the geology of the site and a table containing the shear wave velocity with depth for the array. The dispersion curve data quality and the model fit to the data for ReMi Array 1 appear to be good. The RMS error of the model fit for these data is approximately 80 fUs. EARTH DYNAMICS Spnngfleld Re Mi Study Paye 2 LLC 6/74121 Figure 4-1. Site layout showing location of ReMi array. EARTH DYNAMICS Springfield Re Mi Study Page 3 LLC 6/14121 p -f Image with Dispersion Modeling Picks w Dispersion Curve Showing Picks and Fit 3000 U O 2500 a1 2000 N g L 1500 a > 1000 m Soo — Calculated Dispersion L • Picked Dispersion Ca 5 0 m 0.0 0.1 0.2 0.3 0.4 of Period (s) Vs Model EARTH 0 DYNAMICS LLC 10 20 30 40 Average Vs = 1,571ft/s ac class c " 50 L d N 60 70 80 80 100 0 1000 2000 3000 4000 Shear Wave Velocity (ft/s) Depth Interval (ft) Shear -wave velocity (ft/s) 0-3.5 237 3.5-11.25 675 11.25-27.3 2,875 27.3-100 2,288 Figure 4-2. Re Mi Array 1 Results Spnngfleld Re Mi Study page 4 6114121 EARTH DYNAMICS LLC 5.0 DISCUSSION 5.1 Exploratory Borings NV5 completed exploratory borings to a depth of 37' belowthe ground surface (bgs) near the ReMi array. Preliminary information from the boring logs indicates that soft silts and clays were encountered to an approximate depth of 13 feet bgs. Below 13 feet, dense gravel was encountered, and from 20 to 37 feet dense cobbles were found. The ReMi model appears to be consistent with the information from the boring logs. 5.2 ASCE Classifications ASCE/SEI 7-16 (2017) defines five site classes based upon the average shear -wave velocity of the soil to a depth of 30 Meters (100 feet). The ASCE classification is summarized in Table 5-1. The classifications in Table 1 are incorporated into the International Building Code (IBC 2018). Earthquake shaking is expected to be stronger where shear -wave velocity is lower. Average shear wave velocity to a depth of 100 ft (V.im) is calculated using Equation 5-1. Where: VS(100) _ ... \ Equation 5-1 n = the number of intervals i = the interval number di = the thickness of the ir^ interval in feet Vsi = the velocity of the i"' interval Using Equation 1 and the data in Figure 4-2, the average shear wave velocity to a depth of 100 ft for the ReMi Array is calculated to be 1,571 ff/s. This velocity corresponds to IBC seismic design classification of "C". Table 5-1. Summary of ASCE soil classification EARTH DYNAMICS Spnngfleld Re Mi Study page 5 LLC 6114121 Average S -wave Velocity Class (ft/sec) Description A > 5,000 Hard rock B 2,500-5,000 Rock C 1,200-2,500 Very dense soil and soft rock D 600-1,200 Stift soil EARTH DYNAMICS Spnngfleld Re Mi Study page 5 LLC 6114121 6.0 LIMITATIONS The geophysical methods used in this study involve the inversion of measured data. Theoretically, the inversion process yields an infinite number of models which will fit the data. Further, many geologic materials have the same seismic velocity. We have presented models and interpretations which we believe to be the best fit given the geology and known conditions at the site. However, no warranty is made or intended by this report or by oral or written presentation of this work. Earth Dynamics accepts no responsibility for damages as a result of decisions made or actions taken based upon this report. 7.0 REFERENCES ASCE/SEI 7-16 (2017), Minimum Design Loads for Buildings and other Structures, American Society of Civil Engineers, Structural Engineering Institute, Reston, VA. Louie, J.N. (2001). "Faster, better: shear -wave velocity to 100 meters depth from refraction microtremor arrays", Bull. Seism. Soc. Am., 91, 347-364. Nazarian, S., and Stokoe II, K.H., (1984), "In situ shear -wave velocities from spectral analysis of surface waves", Proceedings for the World Conference on Earthquake Engineering Vol. 8, San Francisco, Calif., July 21-28, v.3, 31-38. IBC (2012) 2012 International Building Code , International Code Council, Washington D. C. RESPECTFULLY SUBMITTED EARTH DYNAMICS LLC Daniel Lauer Partner - Senior Geophysicist EARTH DYNAMICS Spnngfleld Re Mi Study page 6 LLC 6/74121 APPENDIX C APPENDIX C SITE-SPECIFIC SEISMIC HAZARD EVALUATION 1011.1011111411010 The information in this appendix summarizes the results of a site-specific seismic hazard evaluation for the proposed mixed-use development located at 702 North A Street in Springfield Oregon. This seismic hazard evaluation was performed in accordance with the requirements in the 2019 SOSSC, ASCE 7-16, and ASCE 41-17 under rehabilitation objectives BSE -2N and BSE -1N. SITE CONDITIONS REGIONAL GEOLOGY The Eugene -Springfield area is located at the upper end of the main Willamette Valley. The valley is an expression of a major north -south structural trough between the uplifted Coast Range to the west, made of mostly Tertiary Age marine sedimentary rocks, and the Cascade Range to the east, built chiefly of Tertiary volcanic and volcaniclastic rocks. The foothills of the two ranges converge as a band of hills around the southern side of the trough underlain by a mixture of sedimentary and volcanic rocks. These southern highlands are broken by the valleys of the Willamette (Coast and Middle forks), McKenzie, and Long Tom rivers and many smaller tributaries, such as Amazon Creek. The area is built mainly on alluvial gravel, sand, and silt deposited by the Willamette River and its tributaries, lapping onto the edges of the bedrock hills. Some hills are surrounded by these sediments and appear as isolated buttes. In general, the older alluvium surface slopes gently west and north, away from the main sediment sources of the upper Willamette and McKenzie rivers. Some localized areas of fine-grained or organic deposits are also present near the site surface. SUBSURFACE CONDITIONS A detailed description of site subsurface conditions is presented in the main report. SEISMICSETRNG Earthquake Source Zones Three scenario earthquakes were considered for this study consistent with the local seismic setting. Two of the possible earthquake sources are associated with the CSZ, and the third event is a shallow, local crustal earthquake that could occur in the North American Plate. The three earthquake scenarios are discussed below. Regional Events The CSZ is the region where the Juan de Fuca Plate is being subducted beneath the North American Plate. This subduction is occurring in the coastal region between Vancouver Island and northern California. Evidence has accumulated suggestingthat this subduction zone has generated eight great earthquakes in the last 4,000 years, with the most recent event occurring approximately 300 years ago (Weaver and Shedlock, 1991). The fault trace is mapped approximately 50 to 120 km off the Oregon coast. Two types of subduction zone earthquakes are possible and considered in this study: 1. An interface event earthquake on the seismogen is part of the interface between the Juan de Fuca Plate and the North American Plate on the CSZ. This source is reportedly capable of generating earthquakes with a moment magnitude of between 8.5 and 9.0. 2. A deep intra plate earthquake on the seismogen is part of the su bducti ng Juan de Fuca Plate. These events typically occur at depths of between 30 and 60 km. This source is capable of generating an event with a moment magnitude of up to 7.5. Local Events Figure C-1 shows Quaternary faults mapped within a 40 -km radius of the site (USGS, 2020). Figure C-2 shows the interpreted locations of seismic events that occurred between 1904 and 2021 (USGS, 2021). Only the Upper Willamette River fault zone is mapped within a 40 -km radius. A brief discussion the Upper Willamette River fault zone and the next two closest faults is provided below. Upper Willamette River Fault Zone The distance to the surface projection of the fault is mapped at approximately 37 km away from the site. This northwest -striking fault zone marks the northwestern end of the Eugene-Denio zone on the western flank of the Cascade Range. The fault zone is marked by regional lineaments mostly expressed as linear stream valleys, but a few exposures of faults in bedrock have been described along these lineaments. No fault scarps on Quaternary deposits have been described, but an exposure of a fault in Pleistocene gravels and "discontinuities" in Quaternary volcanic rocks are possible evidence of Quaternary displacement. However, some investigators found no evidence of Quaternary displacement on these structures (Person ius, 2002a). Owl Creek Fault The distance to the surface projection of the fault is mapped at approximately 50 km away from the site. The steeply east -dipping Owl Creek fault is a reverse fault associated with an anticline in the Eocene Spencer Formation mapped in the subsurface east of Corvallis on the floor of the southern Willamette Valley. The fault, which has no geomorphic expression, apparently offsets the middle to late Pleistocene Rowland Formation, but does not offset the latest Pleistocene Willamette Formation (Personius, 2002b). Corvallis Fault Zone The distance to the surface projection of the fault is mapped at approximately 60 km away from the site. The northeast -striking, shallowly northwest -dipping Corvallis fault zone forms the western margin of the southern Willamette Valley in the vicinity of Corvallis. The fault thrusts Eocene Siletz River Volcanics over siltstone and sandstone of the Eocene Tyee Formation. The fault may have been reactivated ass steeply dipping, left -lateral strike -slip fault. The fault trace is offset by two northwest -striking, strike -slip faults that appear to be tear faults in the thrust sheet: however, these faults may extend eastward into the Willamette Valley and therefore may not be tear faults. Unequivocal evidence of Quaternary deformation has not been described, so herein the fault is classified as Class B until further studies are conducted (Personi us, 2002c). SEISMIC SITE CLASS Shear wave velocity measurements were completed at the site by Earth Dynamic LLC. Based on the measured shear wave velocities, the depth of the proposed footings, and the absence of liquefaction as discussed in this appendix, the seismic site class for the development is C. Calculations in accordance with ASCE 7-16 Table 20.3-1 for the Vsw below the bottom of the estimated footing depths are shown in Table C-1. Table C-1. Site Class Determination 1. Amu mes"found a tions am located 2 feet below existinggmde(Vs. determination calculated between 2 and 102 feet BGS). SEISMIC DESIGN PARAMETERS Tables C-2 through C-4 presents the site design parameters prescribed by ASCE 7-16 and ASCE 41-17 for rehabilitation objectives BSE -1N and BSE -2N for the site. However, the final design parameters should be determined by the results of the site-specific seismic analysis discussed in the following sections. The building code requires that seismic design parameters associated with a percent probability of being exceeded in a 50 -year period be used in design. Depth Below Shear Wave Interval/Shear Interval Soil Type Foundations Velocity Wave Velocity (feet) (feet BGS) (fps) (second) Native Clay 0 to 1.5 1.5 237 0.00633 Native Clay 1.5 to 9.3 7.8 675 0.01148 Native Gravel 9.3 to 25.3 16 2,875 0.00558 Native Gravel 25.3 to 100 74.7 2,288 0.03265 Sum NA 100 NA 0.05604 Average shear wave velocity in the upper 100 feet below the NA 1,780 foundation, Vsw (fps) Site Class NA C 1. Amu mes"found a tions am located 2 feet below existinggmde(Vs. determination calculated between 2 and 102 feet BGS). SEISMIC DESIGN PARAMETERS Tables C-2 through C-4 presents the site design parameters prescribed by ASCE 7-16 and ASCE 41-17 for rehabilitation objectives BSE -1N and BSE -2N for the site. However, the final design parameters should be determined by the results of the site-specific seismic analysis discussed in the following sections. The building code requires that seismic design parameters associated with a percent probability of being exceeded in a 50 -year period be used in design. Table C-2. ASCE 7-16 Seismic Design Parameters Table C-3. ASCE 41-17 BSE -2N Seismic Design Parameters Parameter Short Period 1 Second Period (Ts=0.2 second) Cr, =1.0 second) MCE Spectral Acceleration, S % = 0.669 g I Si = 0.385 g Site Class C Site Coefficient, F I Fe = 1.232 F, = 1.500 Adjusted Spectral Acceleration, Sx Srs = 0.825 g Sm = 0.578 g Table Cd. ASCE 41-17 BSE -1N Seismic Design Parameters Parameter Short Period I 1 Second Period (T,=0.2 second) (Ti=1.Osecond) Adjusted Spectral Acceleration, Sx I Sx = 0.550 g I Sm = 0.355 g CIII711i.Y:IQ 0MM e101e1\(.969 SITE AND ATTENUA RON RELA RONSHIPS Site Parameters As described in the "Subsurface Conditions" section of the main report and the "Regional Geology" section of this appendix, the site is underlain by dense to very dense gravel over sedimentary and volcanic bedrock. Based on the geologc maps and published well logs in the site area, the gravel/cobble unit is likely 90 to 120 feet thick. Based on our experience with similar soil and the results of our subsurface explorations and ReMi testing, we assigned an average Vs3o of 1,780 fps for the soils within the upper 100 feet below the footings. Short Period 1 Second Period Parameter (Ts =0.2 second) (Ti=1.0 second) MCE Spectral Acceleration, S & = 0.669 g S1 = 0.385 g Site Class C Site Coefficient, F Fe = 1.232 F� = 1.500 Adjusted Spectral Acceleration, Sm Sw = 0.825 g Smi = 0.578 g Design Spectral Response Srw = 0.550 g Sol = 0.385 g Acceleration Parameters, So Table C-3. ASCE 41-17 BSE -2N Seismic Design Parameters Parameter Short Period 1 Second Period (Ts=0.2 second) Cr, =1.0 second) MCE Spectral Acceleration, S % = 0.669 g I Si = 0.385 g Site Class C Site Coefficient, F I Fe = 1.232 F, = 1.500 Adjusted Spectral Acceleration, Sx Srs = 0.825 g Sm = 0.578 g Table Cd. ASCE 41-17 BSE -1N Seismic Design Parameters Parameter Short Period I 1 Second Period (T,=0.2 second) (Ti=1.Osecond) Adjusted Spectral Acceleration, Sx I Sx = 0.550 g I Sm = 0.355 g CIII711i.Y:IQ 0MM e101e1\(.969 SITE AND ATTENUA RON RELA RONSHIPS Site Parameters As described in the "Subsurface Conditions" section of the main report and the "Regional Geology" section of this appendix, the site is underlain by dense to very dense gravel over sedimentary and volcanic bedrock. Based on the geologc maps and published well logs in the site area, the gravel/cobble unit is likely 90 to 120 feet thick. Based on our experience with similar soil and the results of our subsurface explorations and ReMi testing, we assigned an average Vs3o of 1,780 fps for the soils within the upper 100 feet below the footings. Attenuation Relationships We obtained a probabilistic bedrock spectrum for the site usingthe EZ -FRISK 8.07 software package and appropriate attenuation relationships for the three earthquake scenarios. The attenuation relationships used and corresponding weights are presented in Table C-5. Table C-5. Attenuation Relationships Weights for Seismic Sources Faulting Type Ground Motion Prediction Equation Contribution Shallow Faults and Shallow Crustal Background Seismicity Abrahamson et al. (2013) 0.25 Boore et al. (2013) 0.25 Campbell and Bozorgnia (2013) 0.25 Chiou and Youngs (2013) 0.25 Subduction (CSZ) Zhao et al. (2006) 0.33 BC Hydro (Abrahamson et al., 2016) 0.34 Atkinson and Macias (2009) 0.33 Deep Intraslab Zhao et al (2006) 0.5 BC Hydro (Abrahamson et al., 2016) 0.5 PROBABILISRC SEISMIC HAZARD ANALYSIS A site-specific PSHA was completed to produce hazard curves and UHSes for the site using the software program EZ -FRISK 8.07. Since the ground motion models used in the hazard calculation compute the average horizontal component of ground motions, scale factors were applied to adjust the site response results to the MRC as described in ASCE 7-16 (21.2). Accordingto ASCE 7-16 Supplement 1, a scale factor of 1.1 should be used for periods of 0.2 second and shorter, a scale factor of 1.3 should be used for periods of 1.0 second, and a scale factor of 1.5 was used for periods greater than 5 seconds (with averaging in between 0.2 and 1 second and between 1 second and 1.5 seconds). The results of the site response were also modified with risk coefficients using Method 1 outlined in ASCE 7-16 Section 21.2.1.1. A risk coefficient of CRs = 0.869 was applied to the spectrum at periods of 0.2 second or less and a risk coefficient of CR1 = 0.858 was applied to the spectrum at periods greater than 1 second. Linear interpolation was used to compute risk coefficients between periods of 0.2 and 1.0 second. The intent of this is to achieve a 1 percent collapse of the structure in a 50 -year period. Figure C-3 shows the PSHA MCER for the soil profiles analyzed as well as the MCER. SITE-SPECIFIC MCER RESPONSE SPECTRUM ASCE 7-16 Section 21.2.2 (Supplement 1) requires the DSHA spectral response period acceleration at each period is calculated as an 84m percentile, 5 percent damped spectral response acceleration in the direction of maximum horizontal response computed at each period. Per the exception in Section 21.2.2, the deterministic ground motion response spectrum need not be calculated when the largest spectral response acceleration of the probabilistic ground motion response spectrum in Section 21.2.1 (PSHA MCER) is less than 1.2F, The largest spectral response acceleration of the PSHA MCER is approximately 0.819 g. The project -specific Fe from ASCE 7-16 (Site Class C) is 1.232, resulting in 1.2Fa equal to 1.478 g. Because 1.2Fa is larger than the largest spectral response acceleration from the PSHA MCER, a deterministic ground motion response is not required for the project. DESIGN RESPONSE SPECTRUM ASCE 7-16 Section 21.3 states that the site-specific MCER response spectrum is reduced to two- thirds of the acceleration at any period. However, the lower bound for design ground motions is 80 percent of the generalized response spectrum as outlined in ASCE 7-16 Section 11.4.5. The site-specific response spectrum and generalized response spectrum are shown on Figure C-4. DESIGN ACCELERA RON PARAMEIERS The parameter SDS is taken from the site-specific response spectrum as 90 percent of the peak spectral acceleration between periods of 0.2 second and 5.0 seconds. The parameter SD, and Sm are taken as the maximum product of period times spectral acceleration at periods of 1.0 second and 5.0 seconds. Figure C-4 shows the design response spectrum for the project. Figure C-5 shows to adjusted spectral accelerations for BSE -2N and BSE -1N objectives. The final design parameters should not be less than 80 percent of the general response spectra, which is also plotted for each condition. The values of Sms, Smi, S. and Sxi shall be taken as 1.5 times SM, SD1, Ss. and Si. Based on this discussion, the site-specific design parameters are presented in Tables C-6 through C-8 and are shown on Figures C-4 and C-5. Table CE. Recommended Site -Specific Seismic Design Parameters - ASCE-7-16 Parameter Short Period 1 Second Period CT. =0.2second) (Ti=1.0second) Adjusted Spectral Acceleration, Sm SW = 0.819 g Smi = 0.593 g Design Spectral Response AScs = 0.546 g SDi = 0.395 g Acceleration Parameters, SD Table C-7. Recommended Site -Specific Seismic Design Parameters - BSE -2N Short Period 1 Second Period Parameter (T,=0.2 second) (Ti=1.0 second) Adjusted Spectral Acceleration, SSs = 0.819 g S = 0.593 g Table C-8. Recommended Site -Specific Seismic Design Parameters - BSE4N Parameter Short Period 1 Second Period (Ts =0.2 second) (Ti=1.0 second) Adjusted Spectral Acceleration, Sx S = 0.546 g S = 0.395 g GEOLOGIC HAZARDS In addition to ground shaking, site-specific geologic conditions can influence the potential for earthquake damage. Deep deposits of loose or soft alluvium can amplify ground motions, resulting in increased seismic loads on structures. Other geologic hazards are related to soil failure and permanent ground deformation. Permanent ground deformation could result from liquefaction, lateral spreading, Iandsliding, and fault rupture. The following sections provide additional discussion regarding potential seismic hazards that could affect the site. The nearest mapped fault is in excess of 37 km from the site. Consequently, it is our opinion that the probability of surface fault rupture beneath the site is low. LIQUEFACTION AND LAIERAL SPREADING Liquefaction is caused by a rapid increase in pore water pressure that reduces the effective stress between soil particles to near zero. Granular soil, which relies on interparticle friction for strength, is susceptible to liquefaction until the excess pore pressures can dissipate. In general, loose, saturated sand soil with low silt and clay content is the most susceptible to liquefaction. Silty soil with low plasticity is moderately susceptible to liquefaction under relatively higher levels of ground shaking. Based on subsurface conditions and laboratory testing, liquefaction is not considered a hazard. Lateral spreading is a liquefaction -related seismic hazard. Areas subject to lateral spreading are typically gently sloping or flat sites underlain by liquefiable sediments adjacent to an open face, such as riverbanks. Since liquefaction is not considered a hazard, lateral spreading is not expected under design levels of ground shaking. GROUND MORON AMPLIFICATION Soil capable of significantly amplifying ground motions beyond the levels determined by our site- specific seismic response analysis were not encountered during the subsurface investigation program. The main report provides a detailed description of the subsurface conditions encountered. We conclude that the level of amplification determined by our response analysis is appropriate and the building can be designed usingthe levels of ground shaking prescribed by ASCE 7-16 and this report. LANDSLIDE Earthquake -induced Iandsliding generally occurs in steeper slopes comprised of relatively weak soil deposits. Based on our review of the Statewide Landslide Information Database for Oregon, the site is located outside of any landslide hazard zone; therefore, Iandsliding is not considered a hazard for this site. SETTLEMENT Settlement due to earthquakes is most prevalent in relatively deep deposits of dry, clean sand. We do not anticipate that significant settlement will occur during design levels of ground shaking. SUBSIDENCE/UPLIFT Subduction zone earthquakes can cause vertical tectonic movements. The movements reflect coseismic strain release accumulation associated with interplate coupling in the subduction zone. Based on our review of the literature, the locked zone of the CSZ is located in excess of 60 miles from the site. Consequently, we do not anticipate that subsidence or uplift is a significant design concern. LURCHING Lurching is a phenomenon generally associated with very high levels of ground shaking, which cause localized failures and distortion of the soil. The anticipated ground accelerations shown on Figure C-5 are below the threshold required to induce lurching of the site soil. SEICHE AND TSUNAMI The site is not located within any tsunami inundation zones and in proximity to large bodies of water that may develop seiches. Seiches and tsunamis are not considered a hazard in the site vicinity. REFERENCES Abrahamson at al., 2013. Update of the AS08 Ground -Motion Prediction Equations Based on the NG4- West2 Data Set: PEER 2013/ 2014 - May 2013. Abrahamson, Norman, Nicholas Gregor, and Kofi Addo, 2016. BC Hydro Ground Motion Prediction Equations for Subduction Earthquakes. Earthquake Spectra: February 2016, Vol. 32, No. 1, pp. 23-44. ASCE, 2010. Minimum Design Loads for Buildings and Other Structures. ASCE Standard ASCE/SEI 7-010. American Society of Civil Engineers. ASCE, 2016. Minimum Design Loads for Buildings and Other Structures. ASCE Standard ASCE/SEI 7-016. American Society of Civil Engineers. Atkinson, G. M. and Macias, M., 2009. Implements the Subduction Interface GMM of Atkinson & Macias (2009) for large interface earthquakes in the Cascadia subduction zone. "Predicted Ground Motions for Great Interface Earthquakes in the Cascadia Subduction Zone," Bulletin of the Seismological Society of America, 99(3), 1552 - 1578. Boore, D.M., Jonathan P. Stewart, Emel Seyhan, and Gail M. Atkinson, 2013. NGA-West2 Equations for Predicting Response Spectral Accelerations for Shallow Crustal Earthquakes: PEER 2013/2014 - May 2013. Campbell, K. W., and Bozorgnia, Y., 2013. NG4-West2 Campbell-Bozorgnia Ground Motion Model for the Horizontal Components of PGA, PGV, and 5% -Damped Elastic Pseudo -Acceleration Response Spectra for Periods Ranging from 0.01 to 10 sec: PEER 2013/ 2014 - May 2013. Chiou, B. S. J. and Youngs, R. R., 2013. Update of the Chiou and Youngs NGA Ground Motion Model forAverage Horizontal Component of Peak Ground Motion and Response Spectra: PEER 2013/ 2014 - May 2013. Personius, S.F., compiler, 2002a, Fault number 863, Upper Willamette River fault zone, in Quaternary fault and fold database of the United States: U.S. Geological Survey website https://earthquakes.usgs.gov/hazards/gfaults, accessed July 9, 2021 at 2:50 p.m. Personius, S.F., compiler, 2002b, Fault number 870, Owl Creek fault, in Quaternary fault and fold database of the United States: U.S. Geological Survey website httgs://earthquakes.usEs.¢ov/hazards/gfaults, accessed July 9, 2021 at 2:50 p.m. Personius, S.F., compiler, 2002c, Fault number 869, Corvallis fault zone, in Quaternary fault and fold database of the United States: U.S. Geological Survey website httgs://earthguakes.usgs.gov/hazards/gfaults, accessed July 9, 2021 at 2:50 p.m. USGS, 2020 and 2021, Quaternary faultand fold database for the United States, from USGS website https://earthguake.usgs.00v/hazards/gfaults/citation.php. Weaver, C.S. and Shedlock, K.M., 1991, Program for earthquake hazards assessment in the Pacific Northwest: U.S. Geological Survey Circular 1067, 29 logs. Zhao J X, Zhang J, Asano A, Ohno Y, Oouchi T, Takahashi T, Ogawa H, Irikura K, Thio H K. Somerville P G, Fukushima Y, Fukushima Y, 2006. Attenuation relations of strong ground motion in Japan using site classification based on predominant period. Bull Seism Soc Am 96: 898-913. 5 '�� SnMn olb ke aC5 be 9 ... r Eno. HERE, Gannin; USGS. InreimaV. INCREMENT P UPC- Lsrl Japan, MCII. Csn Chine (Heng Kong} Lar Kalea Csd I Iholandl, NGnc Icl GpenStre,'Map cor ib Wor9 sntl the GIS User Connini LEGEND NN O RADIUS Coll K * SITE LOCATION — USGS QUATERNARY FAULTS 0 20 40 Kilometers USGS, accessed November 10, 2020. Quaternary Fault and Fold Database of the United States, U.S. Geological Survey, Available: httins://ww.v.usgs.90s/natural-hazards/earthquake-hazards/faults NWSPROP-2-Ol QUATERNARY FAULT MAP N 5 JULY 2021 ASTREET MWED-USE PROJECT FIGURE C-1 SPRINGFIELD, OR rJp�'�0 i 1/116. 0 0 I w� cm o� rH o 0.J o _ Sources Eni_ HERE, Gannin, U5G5. Inle,mnp. INCREMENT P NRC. , 0 Lsr Japan MCTI, L, Cline lHoro KOog), Est Korea Lsn l lhallendl, NGGC, (c) Gp—Str—Map cv 1ru.1—, antl Ilia GIS Ose� Go[nmu Nly LEGEND ///''NN Q RADIUS (40 (M) * SITE LOCATION INSTRUMENTAL EARTHQUAKE MAGNITUDE 0 20 40 a 2.0 - 3.0 O 3.0-4.0 Kilometers 4.0-6.0 • > 6.0 USOS, accessed April 19, 2021, Earthquake Hazards Program, US Earthquake Information by State, U.S. Ceological Survey, Ayailable. https://..usgs.gov/natural-hazards/earthquake-hazards/earthquakes Earthquakes in figure are from 1904-2021. NMPROP-2-01 HISTORICAL SEISMICITY MAP N 5 JULY 2021 ASTREET MWED-USE PROJECT FIGURE C-2 SPRINGFIELD, OR ,ovam-rce oe�. MM : 7/WT 1-0 — — -- I____F-- I I -I-- -I- —PSHA MCER and Site -Specific MCER 0.8 --- -- — --- NOTES: 1. 5 Percentdamping 0.6 — �I 0.4 #1 TI IT 0.2 --- -- — --- T — — 1 0.0 0.0 0.5 1.0 1.5 LO J.5 3.0 3.5 4.0 4.5 S.0 Period (seconds) N 5 N PROP -2-01 MCE, JULY 2021 AST REST MIXED-USE PROJECT FIGURE C-3 SPRINGFIELD, OR MPI,Ml-r oem. NM : 7/WT —80 Percent ASCE 7-16 Class C Design Response Spectrum (Lower Limit) —Site -Specific Response Spectrum from Analysis 1 ` 0.5 `i Design Response Spectrum — NOTES: • `� 1. 5 Percent damping • `�- -- 2. Values correspond to 2/3 MCEa --- — 0.4 I I m 0.3 1A 01 0.1 0.0 0.0 0.5 1.0 1.5 2.0 ?.5 3.0 3.5 4.0 4.5 5.0 Period (seconds) NNSPROP-2-01 DESIGN RESPONSE SPECTRUM N 5 JULY 2021 MIXED-USE PROJE ASTREET CT FIGURE C-4 SPRINGFIELD, OR —80 Percent ASCE 7-16 Class C Design Response Spectrum (Lower Limit) —Site -Specific Response Spectrum from Analysis 1 ` `i Design Response Spectrum — NOTES: • `� 1. 5 Percent damping • `�- -- 2. Values correspond to 2/3 MCEa --- — I I 5P,,Ml-r Amx MMM : 7/WT 0.9 — --- 111111111111111111 1 0.8 —8SE-2N Adjusted Acceleration BSE -1 N Adjusted Acceleration 0.7 0.6NOTES: "l. 5 Percentdamping 0-5 ro 04 SII II II 03 0.2 0.1 TIR ii 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Period (seconds) N 5 NNSPROP-2-01 BSE ADJUSTED ACCELERATIONS JULY 2021 ASTREET MIXED-USE PROJECT FIGURE C-5 SPRINGFIELD, OR Delivering Solutions N V 5 Improving Lives