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Exhibit I_Level 1 Geotechnical Investigation Report
Level I Geotechnical Investigation Report Eugene Riverfront Development Infrastructure East 3rd Avenue to East 8th Avenue Eugene, Oregon Prepared for: City of Eugene 99 E. Broadway, Suite 400 Eugene, Oregon 97401 April 4, 2019 PBS Project 73368.001 4412 SW CORBETT AVENUE PORTLAND, OR 97239 503.248.1939 MAIN 866.727.0140 FAX PBSUSA.COM Level I Geotechnical Investigation Report Eugene Riverfront Development Infrastructure East 3rd Avenue to East 8th Avenue Eugene, Oregon Prepared for: City of Eugene 99 E. Broadway, Suite 400 Eugene Oregon 97401 April 4, 2019 PBS Project 73368.001 Prepared by: Reviewed by: Ejhjubmmz!tjhofe!cz! Szbo!Xijuf-!QF-!HF! Ebuf;!312:/15/15! 24;23;65!.18(11( 6/30/2020 Ryan White, PE, GE Saiid Behboodi, PE, GE Geotechnical Engineering Group Manager Principal Geotechnical Engineer ©2019PBS Engineering and Environmental Inc. 4412 SW CORBETT AVENUE, PORTLAND, OR 97239 503.248.1939 MAIN 866.727.0140 FAX PBSUSA.COM Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon TABLE OF CONTENTS 1INTRODUCTION .............................................................................................................................................. 1 1.1General ........................................................................................................................................................................................... 1 1.2Purpose and Scope ................................................................................................................................................................... 1 1.2.1Literature and Records Review ................................................................................................................................ 1 1.2.2Subsurface Explorations ............................................................................................................................................. 1 1.2.3Report Preparation ....................................................................................................................................................... 1 1.3Project Understanding ............................................................................................................................................................. 1 2SITE CONDITIONS ........................................................................................................................................... 1 2.1Surface Description ................................................................................................................................................................... 1 2.2Geologic Setting ......................................................................................................................................................................... 2 2.3Subsurface Conditions ............................................................................................................................................................. 2 2.4Groundwater ................................................................................................................................................................................ 2 3GEOLOGIC AND SEISMIC HAZARDS ............................................................................................................. 2 4CONCLUSIONS AND RECOMMENDATIONS ................................................................................................ 4 4.1Summary of Subsurface Conditions ................................................................................................................................... 4 4.2Summary Geologic and Seismic Hazards ......................................................................................................................... 4 4.3Geotechnical Design Considerations ................................................................................................................................. 4 4.4Additional Explorations ........................................................................................................................................................... 4 5LIMITATIONS .................................................................................................................................................. 5 6REFERENCES .................................................................................................................................................... 6 SUPPORTING DATA TABLES Table 1. Summary of Potential Geologic and Seismic Hazards FIGURES Figure 1 Vicinity Map Figure 2 Site Plan Figure 3 Site Topography Figure 4 Relative Earthquake Hazard Figure 5 Relative Earthquake Amplification Hazard Figure 6 Relative Slope Instability Hazard APPENDICES APPENDIX A: Field Explorations by PBS APPENDIX B: Field Explorations by Others April 4, 2019 i PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon 1INTRODUCTION 1.1 General This report presents initial results of PBS Engineering and Environmental Inc. (PBS) geotechnical engineering services for the proposed Eugene Riverfront Development Infrastructure commissioned by the City of Eugene. The project site is located along the west side of the Willamette River between East 3rd Avenue and East 8th Avenue in Eugene, Oregon (site). The general site location is shown on the Vicinity Map, Figure 1. The locations of explorations completed by PBS and others in relation to existing site features are shown on the Site Plan, Figure 2. 1.2 Purpose and Scope for this Level I Investigation report was to summarize subsurface conditions at the site and identify any known or potential geotechnical or geologic hazards that may impact the site and/or development. This was accomplished by performing the following scope of services. 1.2.1Literature and Records Review PBS reviewed various published geologic maps of the area for information regarding geologic conditions and hazards at or near the site. PBS also reviewed previously completed reports for the project site and vicinity. 1.2.2Subsurface Explorations PBS recently completed explorations for the proposed Downtown Riverfront Park, included in Appendix A, and in the former hog fuel stockpile area at the site. In addition, PBS has reviewed subsurface explorations completed by Squier Associates in 1986 at the site for EWEB Headquarters and Operations facilities, included in Appendix B. 1.2.3Report Preparation This Level I Investigation Report summarizes the results of explorations and observations at the site, including information relating to the following: Field exploration logs and site plan showing approximate exploration locations Groundwater levels and considerations Discussion geotechnical and geologic hazards Summary of subsurface conditions Recommendations for additional exploration 1.3Project Understanding Development plans are currently in the conceptual stages; however, development of the site will likely include a combination of new roads and utilities that will support multi-story, mixed-use commercial and residential development, as well as possibly small, lightly-loaded parking structures. Development will likely also include paths, open space, and landscape improvements that tie the proposed development into the adjacent park. 2SITE CONDITIONS 2.1Surface Description The proposed development will extend from approximately East 3rd Avenue at the north to East 8th Avenue at the south. The majority of the property was formerly occupied and used by the Eugene Water and Electric Board (EWEB). The northern, approximate quarter of the proposed development will be constructed in an existing park that includes grass, trees, shrubs, and bike and pedestrian paths. The southern, approximate three-quarters of the development area is occupied by paved access roads and parking areas, gravel surfaced parking, and several structures. The western portion of the proposed development is relatively flat. The park April 4, 2019 1 PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon property separates the proposed development from the river. Slopes down to the river are covered with brush and trees. Several structures, asphalt concrete pavement, concrete pavement, and concrete slabs occupy large portions of the proposed development, many of which will demolished as part of future development. 2.2Geologic Setting The site is located within the southern Willamette Valley, a broad alluvial basin within the physiographic province of the Puget-Willamette Lowland that separates the Cascade Range to the east from the Oregon Coast Range to the west, and extends from the Puget Sound to Eugene, Oregon (Yeats, et al., 1996). The Willamette Valley is situated along the Cascadia Subduction Zone (CSZ) where oceanic rocks of the Juan de Fuca Plate subducting beneath the North American Plate have created complex deformation within the Coast Range and Willamette Valley basement rocks (McClaughry, et al., 2010). Extensive valley infilling and catastrophic flooding related to the Missoula Floods during the Quaternary has subsequently buried the Oligocene and Eocene sedimentary and volcanic basement rocks within the valley and concealed many of the structural features throughout the valley (Wiley, 2006). Locally the site is underlain by Holocene age alluvium associated with the nearby active channel of the Willamette River and modern-day flooding. These sediments consist of unconsolidated gravel, sand, silt and clay and may be as much as 50 feet thick (McClaughry, et al., 2010). 2.3Subsurface Conditions Portions of the site have been explored by Squier Associates in 1986 by completing 33 borings to depths of 8.1 feet to 41.5 feet bgs and by PBS in 2018 and 2019 by completing 17 borings to depths of 11.5 to 36.5 feet bgs. PBS boring logs are included in Appendix A and Squier boring logs are included in Appendix B. In general, subsurface conditions at the site consist of gravel fill; a layer of clay, silt, silty sand, and sand; and a layer of gravel overlying very stiff silt, interpreted as the Eugene Formation. PBS did not encounter hog fuel in any of the explorations recently completed in the former hog fuel stockpile area identified in the Squier report. 2.4Groundwater Static groundwater was not measured during drilling of the deeper explorations due to the mud-rotary drilling techniques used. Based on the presence of relatively permeable gravel and the proximity to the Willamette River, we estimate these are hydraulically connected and the water levels in the river may reflect the elevation of groundwater on the site. Previous geotechnical explorations at the site generally encountered groundwater at depths of 15 to 20 feet bgs. 3GEOLOGIC AND SEISMIC HAZARDS Geologic and seismic hazards are defined as those conditions associated with the geologic and seismic environment that could influence existing and/or proposed improvements. In general, the geologic and seismic hazards most commonly associated with the physical and chemical characteristics of near-surface soil, rock, and groundwater include those listed below. Those shown in bold are geologic and seismic hazards that could affect the site development and should be considered in the planning process. April 4, 2019 2 PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon Slope stability Hydrology and drainage Volcanic hazards Adverse soils Hazardous Minerals Permafrost and freeze-thaw Land subsidence Erosion and sedimentation Seismic hazards (liquefaction, lateral spreading, earthquake-induced Subsurface voids Hydrogeology and groundwater landslides, ground shaking, fault ground rupture, tsunamis and seiches) Specific hazards are presented in Table 1 on our engineering and geological judgment. Where noted, the terminology is taken from a specific source (e.g., HazVu, FEMA). Table 1. Summary of Potential Geologic and Seismic Hazards Geologic and Seismic Hazard Examples Level of Concern Artificial Fill High Expansive Soil Low Adverse Soils Compressible Soil Moderate Organic-Rich Soil Low Sensitive Clay N/A Flooding a Low Hydrology and Drainage Standing Water Low Shallow Groundwater b Low Hydrogeology and Groundwater Seepage and Piping Low Permeability and Percolation Low Ground Amplification c,d Low d Local Fault Rupture Low c,ee Liquefaction and Lateral Spread Low Seismically-Induced Settlement N/A Seismic Hazards Ground Lurching or Cracking Low Seismically-Induced Slope Instability N/A Tsunami N/A Seiches Low a Information from the Department of Geology and Mineral Industries (DOGMAI), Oregon HazVu: Statewide Geohazards Viewer, https://gis.dogami.oregon.gov/maps/hazvu/. Site is not within the FEMA 100-year flood zones. b Groundwater is assumed to be hydraulically connected to the Willamette River elevation. Anticipated to be approximately between 15 feet bgs. c Information from the Department of Geology and Mineral Industries (DOGAMI), IMS-14. d Information from the Department of Geology and Mineral Industries (DOGMAI), Oregon HazVu: Statewide Geohazards Viewer, http://gis.dogami.oregon.gov/maps/hazvu/. Site is mapped as expected earthquake shaking equal to strong e Although DOGAMI mapping indicates a potential for liquefaction at the site, subsurface conditions (i.e., type and relative density of site soils and depth of groundwater) would correspond to a low hazard that will impact the building design and site development. undocumented, variable fill materials. These materials may consist of backfill in the form of dense gravels to debris. Subsurface voids may be encountered due to fill placement and its material types. The primary seismic hazards are liquefaction/lateral spreading. Current mapping shown through the online HazVu program indicates liquefaction may be a potential hazard at the site. However, based on subsurface conditions in the site vicinity and depth to groundwater, our current opinion is that the risk of liquefaction and lateral spreading at the site is low. Liquefaction is a phenomenon whereby shaking of a saturated soil causes its material properties to change so that it behaves as a liquid. April 4, 2019 3 PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon The 2014 OSSC methodology defines six soil categories that are based on average shear-wave velocity in the upper 100 feet (30 m) of the soil column. The shear-wave velocity is the speed with which a particular type of ground vibration travels through a material, and can be measured directly by several techniques. The six soil categories are Hard Rock (A), Rock (B), Very Dense Soil and Soft Rock (C), Stiff Soil (D), Soft Soil (E), and Special Soils (F). Based on these criteria, the site corresponds to Site Class D. 4CONCLUSIONS AND RECOMMENDATIONS 4.1Summary of Subsurface Conditions Subsurface conditions at the site generally include zones of fill, clay/silt/sand, and gravel, underlain by very stiff silt (Eugene Formation). Groundwater is likely hydraulically connected to the adjacent Willamette River and based on previous monitoring at the site by others, is present at depths of 15 to 20 feet bgs. 4.2Summary Geologic and Seismic Hazards The fill at the site is variable in content and thickness, but in several locations consists of gravel without debris. However, based on previous development and historic activity at the site, fill that includes construction debris such as brick, concrete, metal, plastic, etc., should be anticipated, particularly in the upper 10 to 15 feet. Zones of soft silt and clay may be compressible under moderate to high loads and should be evaluated on a site-specific basis, depending on the proposed development. Based on the soils encountered in the explorations completed to date at the site and those completed by others, the risk of encountering expansive soils at the site is low. Based on the type and relatively density of site soils and the depth of groundwater at the site, the risk of liquefaction and lateral spreading following a code-based earthquake is low. The site is located outside the 100-year flood plain. 4.3Geotechnical Design Considerations The subsurface conditions at the site generally consist of gravel fill over silt and fine- to coarse-grained sand and gravel underlain by Eugene Formation. Based on our observations and analyses, conventional foundation support of lightly loaded park-type structures on shallow spread footings appears feasible. Similarly, support of at-grade hard surfaces such as paths, walkways, courtyards, and vehicular pavements are feasible. Excavation with conventional equipment is feasible at the site. The grading and final development plans for the project had not been completed when this report was prepared. Once completed, PBS should be engaged to review the project plans and update our recommendations as necessary. Development will likely include multi-story and mid-rise structures. Previous development of the site includes several structures that were supported on piles that terminated with limited embedment into the Eugene Formation. Depending on the type, size, location, and foundation loads associated with future development of portions of the site, foundation support on piles may be necessary. 4.4Additional Explorations PBS is currently under contract with the City of Eugene to provide a geotechnical engineering report for the proposed development infrastructure. These services include the recent completion of an additional eleven geotechnical borings to depths of up to 25 feet bgs (shown on Figure 2), installation of piezometers to April 4, 2019 4 PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon monitor groundwater elevations at the site, and provide geotechnical recommendations for design and construction for site development. In addition, block-specific exploration, testing, and analyses will be required for development of individual blocks, the extent of which will be a function of the size and type of the proposed development. 5LIMITATIONS This report has been prepared for the exclusive use of the addressee, and their architects and engineers, for aiding in the design and construction of the proposed development and is not to be relied upon by other parties. It is not to be photographed, photocopied, or similarly reproduced, in total or in part, without express written consent of the client and PBS. It is the addressee's responsibility to provide this report to the appropriate design professionals, building officials, and contractors to ensure correct implementation of the recommendations. The opinions, comments, and conclusions presented in this report are based upon information derived from our literature review, field explorations, laboratory testing, and engineering analyses. It is possible that soil, rock, or groundwater conditions could vary between or beyond the points explored. If soil, rock, or groundwater conditions are encountered during construction that differ from those described herein, the client is responsible for ensuring that PBS is notified immediately so that we may reevaluate the recommendations of this report. Unanticipated fill, soil and rock conditions, and seasonal soil moisture and groundwater variations are commonly encountered and cannot be fully determined by merely taking soil samples or completing explorations such as soil borings. Such variations may result in changes to our recommendations and may require additional funds for expenses to attain a properly constructed project; therefore, we recommend a contingency fund to accommodate such potential extra costs. The scope of work for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. If there is a substantial lapse of time between the submission of this report and the start of work at the site, if conditions have changed due to natural causes or construction operations at or adjacent to the site, or if the basic project scheme is significantly modified from that assumed, this report should be reviewed to determine the applicability of the conclusions and recommendations presented herein. Land use, site conditions (both on and off site), or other factors may change over time and could materially affect our findings; therefore, this report should not be relied upon after three years from its issue, or in the event that the site conditions change. April 4, 2019 5 PBS Project 73368.001 Level I Investigation Report Eugene Riverfront Development City of Eugene Eugene, Oregon 6REFERENCES ASCE. (2010). Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). L. R. Squier Associates (December 23, 1986). Foundation Investigation, Headquarters Buildings, Proposed EWEB Expansion. Prepared for Eugene Water and Electric Board (EWEB). Squier Project No. 86069A. L. R. Squier Associates (December 23, 1986). Foundation Investigation, Headquarters Buildings, Operations Facility, Proposed EWEB Expansion. Prepared for Eugene Water and Electric Board (EWEB). Squier Project No. 86069B. McClaughry, J. D., Wiley, T. J., Ferns, M. L., and Madin, I. P. (2010). Digital Geologic Map of the Southern Willamette Valley, Benton, Lane, Linn, Marion, and Polk Counties, Oregon. Oregon Department of Geology and Mineral Industries (DOMAGI), open-file report O-10-03. PBS Engineering and Environmental (February 6, 2019). Geotechnical Engineering Services Letter, Eugene Riverfront Development Hog Fuel, Eugene, Oregon. Prepared for City of Eugene. PBS Project 73368.001. OSSC. (2014). Oregon Structural Specialty Code (OSSC). Based on IBC. (2012). International Building Code. Country Club Hills, IL International Code Council, Inc. Wiley, T. J. (2006). Preliminary Geologic Map of the Albany Quadrangle, Linn, Marion, and Benton Counties, Oregon. Oregon Department of Geology and Mineral Industries (DOMAGI), open -file report O-06-26. Yeats, et. al. (1996). Tectonics of the Willamette Valley, Oregon. Oregon: US Geological Survey Professional Paper 1560, 183-222. April 4, 2019 6 PBS Project 73368.001 Figures Site VICINITY MAP ! Portland ^ Salem Site ! Eugene 1 PBS-B-5 B-10 B-9 B-8 B-7 B-6 B-5 B-4E B-19 B-4A B-3 B-4 B-4C B-4D B-4F B-2 B-1 B-16 B-18 B-15 (p) B-14 PBS-B-4 B-17 PBS-B-8 B-2 B-3 B-4 PBS-B-9 B-9D B-9E B-13 (p) B-8 B-9 B-7 B-9C PBS-B-3 B-9B B-10 B-9A PBS-B-7 B-12 B-5 HB-2 HB-5 B-6 PBS-B-6 B-11 HB-4 PBS-B-6 (alt.) HB-1 HB-8 HB-7 B-11 (p) B-12 HB-3 B-13 HB-6 PBS-B-2 B-20 B-10 PBS-B-1 SITE PLAN EXPLANATION 2 EXPLANATION SITE TOPOGRAPHY 3 EXPLANATION Site RELATIVE EARTHQUAKE HAZARD 4 EXPLANATION Site RELATIVE EARTHQUAKE AMPLIFICATION HAZARD 5 EXPLANATION Site RELATIVE SLOPE INSTABILITY HAZARD 6 Appendix A Field Explorations Table A-1 Terminology Used to Describe Soil 1 of 2 Soil Descriptions Soils exist in mixtures with varying proportions of components. The predominant soil, i.e., greater than 50 percent based on total dry weight, is the primary soil type and is capitalized in our log descriptions (SAND, GRAVEL, SILT, or CLAY). Smaller percentages of other constituents in the soil mixture are indicated by use of modifier words in general accordance with the ASTM D2488-06 Visual-Manual Procedure. may have been followed. In accordance with ASTM D2488-06, group symbols (such as GP or CH) are applied on the portion of soil passing the 3-inch (75mm) sieve based on visual examination. The following describes the use of soil names and modifying terms used to describe fine- and coarse-grained soils. Fine-Grained Soils (50% or greater fines passing 0.075 mm, No. 200 sieve) The primary soil type, i.e., SILT or CLAY is designated through visual-manual procedures to evaluate soil toughness, dilatency, dry strength, and plasticity. The following outlines the terminology used to describe fine-grained soils, and varies from ASTM D2488 terminology in the use of some common terms. Plasticity Plasticity Primary soil NAME, Symbols, and Adjectives Description Index (PI) SILT (ML & MH) CLAY (CL & CH) ORGANIC SOIL (OL & OH) SILT Organic SILT Non-plastic 0 3 SILT Organic SILT Low plasticity 4 10 SILT/Elastic SILT Lean CLAY Organic SILT/ Organic CLAY Medium Plasticity 10 20 Elastic SILT Lean/Fat CLAY Organic CLAY High Plasticity 20 40 Elastic SILT Fat CLAY Organic CLAY Very Plastic >40 Modifying terms describing secondary constituents, estimated to 5 percent increments, are applied as follows: Description % Composition With Sand 15% to 25% plus No. 200 % Sand < % Gravel With Gravel Sandy 30% to 50% plus No. 200 Gravelly % Sand < % Gravel Borderline Symbols, for example CH/MH, are used when soils are not distinctly in one category or when variable soil units contain more than one soil type. Dual Symbols, for example CL-ML, are used when two symbols are required in accordance with ASTM D2488. Soil Consistency terms are applied to fine-grained, plastic soils (i.e., PI > 7). Descriptive terms are based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586-84, as follows. SILT soils with low to non-plastic behavior (i.e., PI < 7) may be classified using relative density. Consistency Unconfined Compressive Strength SPT N-value Term tsf kPa Very soft Less than 2 Less than 0.25 Less than 24 Soft 2 4 0.25 0.5 24 48 Medium stiff 5 8 0.5 1.0 48 96 Stiff 9 15 1.0 2.0 96 192 Very stiff 16 30 2.0 4.0 192 383 Hard Over 30 Over 4.0 Over 383 Table A-1 Terminology Used to Describe Soil 2 of 2 Soil Descriptions C oarse - Grained Soils (less than 50% fines) Coarse-grained soil descriptions, i.e., SAND or GRAVEL, are based on the portion of materials passing a 3-inch (75mm) sieve. Coarse-grained soil group symbols are applied in accordance with ASTM D2488-06 based on the degree of grading, or distribution of grain sizes of the soil. For example, well-graded sand containing a wide range of grain sizes is designated SW; poorly graded gravel, GP, contains high percentages of only certain grain sizes. Terms applied to grain sizes follow. Particle Diameter Material NAME Inches Millimeters SAND (SW or SP) 0.003 0.19 0.075 4.8 GRAVEL (GW or GP) 0.19 3 4.8 75 Additional Constituents: Cobble 3 12 75 300 Boulder 12 120 300 3050 The primary soil type is capitalized, and the fines content in the soil are described as indicated by the following examples. Percentages are based on estimating amounts of fines, sand, and gravel to the nearest 5 percent. Other soil mixtures will have similar descriptive names. Example: Coarse-Grained Soil Descriptions with Fines >5% to < 15% fines (Dual Symbols) 15% to < 50% fines Well graded GRAVEL with silt: GW-GM Silty GRAVEL: GM Poorly graded SAND with clay: SP-SC Silty SAND: SM Additional descriptive terminology applied to coarse-grained soils follow. Example: Coarse-Grained Soil Descriptions with Other Coarse-Grained Constituents Coarse-Grained Soil Containing Secondary Constituents With sand or with gravel 15% sand or gravel With cobbles; with boulders Any amount of cobbles or boulders. Cobble and boulder deposits may include a description of the matrix soils, as defined above. Relative Density terms are applied to granular, non-plastic soils based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586-84. Relative Density Term SPT N-value Very loose 0 4 Loose 5 10 Medium dense 11 30 Dense 31 50 Very dense > 50 Table A-2 Key To Test Pit and Boring Log Symbols SAMPLING DESCRIPTIONS LOG GRAPHICS Soil and Rock SamplingInstrumentation Symbols Detail Lithology Boundary: Ground Surface separates distinct units Well Cap Sample (i.e., Fill, Alluvium, Recovery Well Seal Sample Bedrock) at Interval approximate depths Well Pipe inciated Piezometer Soil-type or Material-type Change Boundary: separates soil Well Screen Sampler and material changes within the Piezometer Type same lithographic unit at Bottom of Hole approximate depth indicated Geotechnical Testing Acronym Explanations PPPocket PenetrometerHYDHydrometer Gradation TORTorvaneSIEVSieve Gradation Dynamic Cone Penetrometer DCPDSDirect Shear ATTAtterberg LimitsDDDry Density PLPlasticity LimitCBRCalifornia Bearing Ratio LLLiquid LimitRESResilient Modulus PIPlasticity IndexVSVane Shear P200Percent Passing US Standard No. 200 SievebgsBelow ground surface OCOrganic ContentMSLMean Sea Level CONConsolidationHCLHydrochloric Acid UCUnconfined Compressive Strength Details of soil and rock classification systems are available on request. Rev. 02/2017 Appendix B