REPORT OF GEOTECHNICAL ENGINEERING SERVICES · PDF fileREPORT OF GEOTECHNICAL ENGINEERING SERVICES Proposed Portland Campus Development 325 and 333 SW Harrison Street Portland, Oregon

REPORT OF GEOTECHNICAL ENGINEERING SERVICES Proposed Portland Campus Development 325 and 333 SW Harrison Street Portland, Oregon For Core Campus LLC June 20, 2016 GeoDesign Project: CoreCampus-3-01

15575 SW Sequoia Pkwy, Suite 100 l Portland, OR 97224 l 503.968.8787 www.geodesigninc.com

June 20, 2016 Core Campus LLC 2234 W. North Avenue Chicago, IL 60647 Attention: Chad J. Matesi

Report of Geotechnical Engineering Services Proposed Portland Campus Development

325 and 333 SW Harrison Street Portland, Oregon

GeoDesign Project: CoreCampus-3-01 GeoDesign, Inc. is pleased to submit our report of geotechnical engineering services for the proposed Portland Campus development project located at 325 and 333 SW Harrison Street in Portland, Oregon. Our services were conducted in accordance with our proposal dated June 2, 2016. We appreciate the opportunity to be of continued service to you. Please contact us if you have questions regarding this report. Sincerely, GeoDesign, Inc. Brett A. Shipton, P.E., G.E. Principal Engineer cc: Ian Eikanas, KPFF Consulting Engineers (via email only) GJS:BAS:kt

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Document ID: CoreCampus-3-01-062016-geor.docx

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CoreCampus-3-01:062016

TABLE OF CONTENTS PAGE NO. 1.0 INTRODUCTION 1 2.0 PROJECT UNDERSTANDING 1 3.0 PURPOSE AND SCOPE 1 4.0 SITE CONDITIONS 1 4.1 Geologic Setting 1 4.2 Surface Conditions 2 4.3 Subsurface Conditions 2 5.0 CONCLUSIONS 3 6.0 SITE DEVELOPMENT RECOMMENDATIONS 4 6.1 Site Preparation 4 6.2 Excavation 4 6.3 Temporary Slopes 5 6.4 Shoring 5 6.5 Structural Fill 6 6.6 Fill Placement and Compaction 7 7.0 FOUNDATION DESIGN RECOMMENDATIONS 8 7.1 Mat Foundation 8 7.2 Spread Footings 9 8.0 BASEMENT WALLS 10 9.0 SEISMIC DESIGN CRITERIA 11 10.0 OBSERVATION OF CONSTRUCTION 11 11.0 LIMITATIONS 11 REFERENCES 13 FIGURES Lateral Earth Pressures for Braced Walls Figure 1 Surcharge-Induced Lateral Earth Pressures Figure 2 APPENDICES Appendix A Prior Explorations A-1 Site Plan, Exploration Logs, and Laboratory Testing Results Appendix B Site-Specific Seismic Hazard Evaluation B-1 Quaternary Fault Map Figure B-1 Historical Seismicity Map Figure B-2 Site Response Spectra Figure B-3 Site-Specific Response Spectra Figure B-4 Design Response Spectrum Figure B-5 ACRONYMS AND ABBREVIATIONS

1 CoreCampus-3-01:062016

1.0 INTRODUCTION GeoDesign, Inc. has prepared this geotechnical engineering report for use in design and construction of the proposed Portland Campus Building in Portland, Oregon. The site is located northeast of the intersection at SW 4th Avenue and SW Harrison Street. The site location is shown in Appendix A (Figure 1). Acronyms and abbreviations used herein are defined at the end of this document. 2.0 PROJECT UNDERSTANDING The site consists of one city block located northeast of the intersection of SW 14th Avenue and SW Harrison Street. The site is currently used as a parking lot and is paved with AC. The proposed development is 15-story building with 4 levels below grade. The basement extends to a depth approximately 50 feet below existing site grades. Column loads will be on the order 2,300 kips. 3.0 SCOPE OF SERVICES The purpose of our services was to provide geotechnical engineering recommendations for use in design and construction of the proposed structure. The specific scope of our services completed is summarized as follows: Reviewed geotechnical work conducted by Krazan & Associates, other available published

geologic data, and our in-house files for existing information regarding subsurface conditions in the site vicinity.

Provided recommendations for site preparation and grading, including temporary and permanent slopes, fill placement criteria, suitability of on-site soil for fill, subgrade preparation, and recommendations for wet weather construction.

Provided foundation support recommendations and design capacity recommendations for the proposed building. Our recommendations include preferred foundation type, allowable bearing capacity, and lateral resistance parameters.

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 dewatering during construction and subsurface drainage, if required.

Provided a site-specific seismic hazard evaluation in accordance with the 2014 SOSSC and ASCE 7-10.

Prepared this geotechnical engineering report that presents our findings, conclusions, and recommendations.

4.0 SITE CONDITIONS 4.1 GEOLOGIC SETTING The site is located in the western portion of the Portland Basin physiographic province, which is bound by the Tualatin Mountains to the west and south and the Cascade Range to the east and


north. The Portland Basin is described as a fault-bounded, pull-apart basin that was formed by two northwest-trending fault zones (Pratt et al., 2001). The Portland Hills fault zone trends along the west side of the basin and the Frontal Fault Zone trends along the east side of the basin near Lacamas Lake, east of Vancouver, Washington. A review of published geologic literature, previous explorations in the area, and explorations conducted during our investigation indicates the site is underlain by Quaternary flood deposits (Gannet and Caldwell, 1998; Beeson et al., 1991; and Madin, 1990), delineated as the fine-grained facies (Qff). The unit consists of unconsolidated coarse sand to silt with occasional clayey layers. The unit was deposited by multiple catastrophic glacial floods associated with the late Pleistocene (15,500 to 13,000 years before present) Missoula Floods. Thickness of the flood deposits in the site vicinity is approximately 30 to 60 feet. Underlying the flood deposits is the Pliocene to Pleistocene Age (5 million to 1.5 million years before present) Troutdale Formation (QTg), which consists of poorly to moderately consolidated, semi-cemented, subrounded to rounded sand and gravel. The thickness of the Troutdale Formation in the site vicinity is approximately 100 to 150 feet (Gannet and Caldwell, 1998; Beeson et al., 1991; and Madin, 1990). The Troutdale Formation is underlain by the Miocene Age (20 million to 10 million years before present) CRBG (Tcr), which is a series of basalt flows that originated from southeastern Washington and northeastern Oregon. The CRBG is several hundred feet thick and considered the geologic basement unit for this report. 4.2 SURFACE CONDITIONS The site consists of one city block bound by SW Harrison Street on the south, SW 4th Avenue on the west, and pedestrian walkways on the north and east. The site is currently used as a paved parking lot. The topography of the site is relatively level. Surrounding site development primarily consists of retail, residential, and office space. 4.3 SUBSURFACE CONDITIONS 4.3.1 General Our knowledge of subsurface conditions is based on reviewing the subsurface exploration program conducted by Krazan & Associates. They drilled three borings (B-1 through B-3) to depths ranging from 26.5 to 90.3 feet BGS. The approximate boring locations are presented in Appendix A (Figure 2). The exploration logs and results of the laboratory testing program are presented also in Appendix A. In general, the investigation encountered the following geologic units: fill, silt, sand, and gravel. A description of each unit is summarized below. 4.3.2 Fill All borings encountered a pavement section of 3 to 4 inches of AC. Fill material consisting of crushed rock and silty sand was encountered below the AC to a depth of approximately 4 to 6.5 feet BGS. SPTs show that the fill is loose to medium dense.


4.3.3 Sandy Alluvium Native silty sand to sand with varying proportions of silt is present beneath the fill. This unit extends to depths of approximately 82 to 86.5 feet BGS at the boring locations. SPTs show that the sand is loose to medium dense. Relative density increases with depth; the sand is generally dense below a depth of 50 feet BGS. 4.3.4 Gravel The alluvial sand is underlain by very dense gravel and sand to a depth of 90.3 feet BGS, the maximum depth explored. The gravel contains variable fractions of sand and silt. This geologic unit contains boulders, although none were encountered in the borings drilled on site for the proposed development. Based on our experience, the gravel extends to a depth of well over 100 feet BGS in the site vicinity. 4.3.5 Groundwater Groundwater was not measured in the any of the borings to the total depth completed of 91.3 feet BGS. Perched groundwater may accumulate at shallower depths during the wet season. Groundwater is not anticipated to impact the proposed development. Based on a review of the available information and our experience in the area, typical static groundwater levels likely range from 90 to 95 feet BGS. Based on our experience, the permanent groundwater table might fluctuate more than 10 feet between the extreme wet and dry seasons. The extreme high groundwater level is expected to rise to an elevation of approximately 20 feet (City of Portland datum). 5.0 CONCLUSIONS Based on our geotechnical study, the site can be developed as proposed. Our geotechnical engineering recommendations for use in design and construction of the proposed development are provided in subsequent sections of this report. The following items will have an impact on design and construction of the proposed development. The proposed building can be supported on a mat foundation; dense sand is generally

present at the depth of the proposed basement. Given a basement depth of 50 feet BGS, a seismic site class C is appropriate computing

seismic forces on the building. Shoring will be required to support the excavation. We believe that an anchored soldier pile

shoring system will be the most cost effective. The base of the excavation is above the regional groundwater table. We do not anticipate

extensive construction dewatering operations. The design groundwater level is well below the base of the basement. Structural design does

not need to consider hydrostatic pressure due to groundwater. The site soil is sensitive and easily disturbed when at moisture contents greater than

optimum. The subgrade should be protected from construction traffic.


6.0 SITE DEVELOPMENT RECOMMENDATIONS 6.1 SITE PREPARATION Demolition includes removal of the existing pavements, concrete curbs, and abandoned utilities. Demolished material should be transported off site for disposal. Excavations remaining from removing the utilities and other subsurface elements should be backfilled with structural fill where below planned site grades. Excavation bases should expose firm subgrade before backfilling. The sides of the excavations should be cut into firm material and sloped a minimum of 1.5H:1V. Utility lines abandoned under new structural components should be completely removed and backfilled with structural fill. Soft or loose soil encountered during site preparation should be replaced with structural fill where it is present beneath structural areas. 6.2 EXCAVATION 6.2.1 General Excavation Conventional earthmoving equipment in proper working conditions should be capable of making necessary excavations for site cuts. The sand and sandy soil are prone to raveling, and shoring will be required to maintain vertical excavation walls and protect adjacent facilities. In our opinion, a soldier pile shoring system with tieback anchors is preferred for the support of the four-story, below-grade parking excavation. Geotechnical parameters for use in shoring design are provided in subsequent sections of this report. Groundwater was not encountered in the explorations during the explorations. However, dewatering might be required to control perched groundwater conditions encountered during excavation for the subsurface parking structure. We anticipate that perched groundwater, if encountered, will diminish over time and can be addressed using sumps and pumps internal to the excavation. We recommend placing a layer of stabilization material in the base of the excavation. The contractor has control of the construction schedule and equipment and, therefore, should be responsible for selecting the working blanket thickness. The contractor should be responsible for the thickness of the working blanket and type of material used to construct the working blanket. 6.2.2 Utility Trenches Shoring is not required for trenches that are shallower than 4 feet; shoring will be required for trenches deeper than this. Sloughing of sidewalls is expected to occur in the sandy soil, particularly if perched groundwater is encountered. Trench dewatering may be required to maintain dry working conditions if the invert elevations of the proposed utilities are below the groundwater level. Pumping from sumps located within the trench will likely be effective at removing water resulting from seepage. If groundwater is present at the base of utility excavations, we recommend placing trench stabilization material at the base of the excavation consisting of 1 foot of well-graded gravel, crushed gravel, or crushed rock with a minimum particle size of 4 inches and less than 5 percent by dry weight passing the U.S. Standard No. 4 sieve. The material should be free of organic matter and other deleterious material and should be placed in one lift and compacted until "well keyed."


While we have described certain approaches to the trench excavation, it is the contractor's responsibility to select the excavation and dewatering methods, monitor the trench excavations for safety, and provide any shoring required to protect personnel and adjacent improvements. All trench excavations should be in accordance with applicable OSHA and state regulations. 6.3 TEMPORARY SLOPES The use of temporary slopes during construction will likely not be possible because of site constraints. Where construction slopes are possible, excavation side slopes less than 10 feet high should be no steeper than 1½H:1V, provided groundwater is not present. If slopes greater than 10 feet high are required, GeoDesign should be contacted to make additional recommendations. We recommend a minimum horizontal distance of 5 feet from the edge of the existing improvements to the top of the temporary slope. All cut slopes should be protected from erosion by covering them during wet weather. If sloughing or instability is observed, the slope should be flattened or the cut supported by shoring. 6.4 SHORING We anticipate that an anchored soldier pile shoring will be the most cost effective. The following sections present our recommendations for use in design and construction of shoring. 6.4.1 Lateral Earth Pressures The soldier pile shoring system should be designed using the lateral earth pressures provided on Figure 1. These pressures will allow moderate relaxation of the shoring toward the excavation causing ground surface settlement. Based on our experience, settlement on the order of 1 inch can be expected adjacent to the shoring. We anticipate the settlement will become negligible at a distance of approximately 15 feet from the wall. Surcharge-induced lateral earth pressures can be computed using the methods provided on Figure 2. The lateral earth pressures presented on Figure 1 and 2 are unfactored. 6.4.2 Soldier Piles Structural design of the soldier piles should consider the lateral earth pressures discussed above. In addition, lateral earth pressures on the soldier piles will be subject to compressive forces as a result of the downward component of the of the tie-back anchor loads. We recommend a minimum soldier pile embedment of 5 feet below the base of the excavation. We recommend an allowable end bearing capacity of 10 ksf friction for piles embedded at least 10 below the excavation base. An allowable skin friction of 1 ksf between the concrete and surrounding soil is recommended. In addition, we recommend that the concrete at the tip of the pile have sufficient strength to withstand the imposed vertical loads. 6.4.3 Lagging Lagging will likely consist of pressure-treated lumber or concrete. To maintain the integrity of the excavation, prompt and careful installation of lagging, particularly in areas of seepage and loose soil, is recommended. All voids behind the lagging should be backfilled promptly. 6.4.4 Tieback Anchors The bonded zone for the tieback anchors should be maintained outside of the “unbonded zone” shown on Figure 1. We anticipate that the tieback anchors will be capable of achieving an


ultimate bond strength of between 3 and 5 kips per foot, depending on the method of construction. A variety of methods are available for construction of tie back anchors. Therefore, we recommend that the contractor be responsible for selecting the appropriate bonded length and installation methods to achieve the required anchor capacity. Tieback anchors should be locked off at 100 percent of the design load. Prior to installing production anchors, we recommend that performance tests be conducted on a minimum of three anchors. The purpose of these tests is to verify the installation procedure selected by the contractor before a large number of anchors are installed. Performance tests should be performed to 150 percent of the design load and in accordance with the guidelines provided Recommendations for Prestressed Rock and Soils Anchors (Post Tensioning Institute, 2014). We recommend that proof tests be conducted on all production anchors in accordance with the guidelines presented in Recommendations for Prestressed Rock and Soils Anchors. The anchors should be proof tested to at least 133 percent of the design load. 6.5 STRUCTURAL FILL Structural fill includes fill beneath foundations, slabs, pavements, any other areas intended to support structures, or within the influence zones of structures. Structural fill should be free of organic matter and other deleterious materials and, in general, should consist of particles no larger than 3 inches in diameter. Recommendations for suitable fill materials are provided in the following sections. 6.5.1 On-site Native Soil The on-site native soil will be suitable for use as structural fill only if it can be moisture conditioned. Based on our experience, the on-site silty soil is sensitive to small changes in moisture content and may be difficult to compact adequately during wet weather or when its moisture content is more than a few percentage points above optimum. 6.5.2 Select Granular Fill Granular material for use as structural fill 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 weight passing the U.S. Standard No. 200 sieve. Granular fill used during periods of prolonged dry weather may have up to 10 percent by dry weight passing the U.S. Standard No. 200 sieve, provided it is properly moisture conditioned. 6.5.3 Pipe Bedding Utility trench backfill for bedding and in the pipe zone should consist of well-graded granular material with a maximum particle size of ¾ inch and less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve, or as required by the pipe manufacturer. 6.5.4 Crushed Rock Crushed rock will be required as base material for floor slabs and pavements as specified. Crushed rock fill should consist of imported clean, durable, crushed, angular rock that meets the requirements of the pertinent sections of this report.


6.6 FILL PLACEMENT AND COMPACTION Fill soil should be compacted at a moisture content that is near optimum. The maximum allowable moisture content varies with the soil gradation and should be evaluated during construction. Fill and backfill material should be placed in uniform, horizontal lifts and compacted with appropriate equipment. The maximum lift thickness will vary depending on the material and compaction equipment used, but should generally not exceed the loose thicknesses provided in Table 1. Fill material should be compacted in accordance with the compaction criteria provided in Table 2.

Table 1. Recommended Uncompacted Lift Thickness

Compaction Equipment

Recommended Uncompacted Lift Thickness (inches)

Silty Soil Granular and Crushed

Rock Maximum Particle Size 1½ inches

Crushed Rock Maximum Particle Size > 1½ inches

Hand Tools: Plate Compactor and Jumping Jack

4 to 8 4 to 8 Not Recommended

Rubber-Tired Equipment 6 to 8 10 to 12 6 to 8

Light Roller 8 to 10 10 to 12 8 to 10

Heavy Roller 10 to 12 12 to 18 12 to 16

Hoe Pack Equipment 12 to 16 18 to 24 12 to 16

The above table is based on our experience and is intended to serve only as a guideline. The information provided in this table should not be included in the project specifications.

Table 2. Compaction Criteria

Fill Type

Compaction Requirements in Structural Zones

Percent Maximum Dry Density Determined by ASTM D 1557

0 to 2 Feet Below Subgrade (percent)

> 2 Feet Below Subgrade (percent)

Pipe Zone (percent)

Area Fill 95 92 -----

Aggregate Base 95 95 -----

Trench Backfill1 95 92 902

Retaining Wall Backfill 953 923 -----

1. Trench backfill above the pipe zone in nonstructural areas should be compacted to 85 percent. 2. Or as recommended by the pipe manufacturer. 3. Should be reduced to 90 percent within a horizontal distance of 3 feet from the retaining wall.


6.6.1 Area Fills Imported fill placed to raise site grades should be placed on a prepared subgrade that consists of firm, inorganic site soil or compacted fill. The fill material should be placed in uniform horizontal lifts and compacted to the recommended minimum density provided in Table 2. 6.6.2 Aggregate Bases Aggregate base materials under foundations and floor slabs should be placed on a prepared subgrade that consists of firm, inorganic native soil or compacted fill. Aggregate base material should be placed in uniform horizontal lifts and compacted to the recommended minimum density provided in Table 2. 6.6.3 Trench Backfill Trench backfill in structural areas should consist of select granular fill or crushed rock as described in the “Structural Fill” section of this report and be compacted to the minimum density provided in Table 2. Pipe bedding and fill in the pipe zone should be compacted to the minimum density presented in Table 2 or as recommended by the pipe manufacturer. 6.6.4 Retaining Wall Backfill Retaining wall backfill should be compacted to the recommended minimum density provided in Table 2, except that fill within 3 horizontal feet of the wall should be placed in uniform horizontal lifts and compacted to a lesser density of 90 percent of the maximum density, as determined by ASTM D 1557, to reduce the effect of compaction-induced stresses against the retaining wall. Settlement of up to 1 percent of the wall height commonly occurs immediately adjacent to retaining walls as the walls rotate and develop lateral active earth pressures. Consequently, we recommend that flatwork (slabs, sidewalks, or pavement) placed adjacent to retaining walls be postponed at least four weeks following wall construction, unless survey data indicates that settlement is complete prior to that time. 7.0 FOUNDATION DESIGN RECOMMENDATIONS In our opinion, the building can be supported on a mat foundation that bears on the sand at a depth of 50 feet BGS. Smaller structures with lightly loaded footings can be supported on spread footings. Our recommendations for use in design and construction of foundations are presented below. 7.1 MAT FOUNDATION 7.1.1 Subgrade Reaction Modulus Due to the large area, the influence zone of the average mat foundation contact pressure extends deeper into the subsurface soil. A mat bearing on the dense sand can be designed using a lower bound subgrade reaction modulus of 200 pci and an upper bound of 400 pci.


7.1.2 Bearing Capacity and Settlement We recommend that the average sustained allowable contact pressure from dead and long-term live loads not exceed 6,000 psf. The maximum contact pressure should be limited to 12,000 psf. These values can be increased by 50 percent when considering short term loads such as wind and seismic forces. We estimate the total post-construction settlement associated with average contact pressures of 6,000 psf will be less than 1 inch. We anticipate the actual load distribution and stiffness of the mat will limit differential settlement to half of the total predicted settlement. 7.1.3 Lateral Resistance Lateral loads on footings can be resisted by passive earth pressure on the sides of the buried structure and by friction along the base of the mat. The available passive earth pressure is 350 pcf modeled as an equivalent fluid pressure. The upper 12 inches of adjacent unpaved areas should not be considered when calculating passive resistance. An ultimate coefficient of friction value equal to 0.40 may be used when calculating resistance to sliding for foundations bearing on gravel. 7.1.4 Subgrade Preparation We recommend the mat foundation be underlain by at least 6 inches of imported crushed rock as a leveling course. The crushed rock should conform to Oregon Department of Transportation standards for aggregate base and should contain less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve. The crushed rock base should be placed in a single lift and compacted to 95 percent of the maximum dry density, as determined by ASTM D 1557 (modified proctor). A thicker section may be required to protect the subgrade; the thickness of this section should be determined by the contractor. Any soft or loose material should be removed from the subgrade prior to placing the crushed rock. The resulting excavation should be backfilled with structural fill in accordance with recommendations in this report. 7.2 SPREAD FOOTINGS Lightly loaded structures such as canopies constructed near current site grades can be supported on conventional spread footings bearing on undisturbed native soil or structural fill overlying this material. Our recommendations assume that column loads are less than 100 kips. Footings should not be supported on the undocumented fill unless it is determined that is competent. 7.2.1 Bearing Capacity We recommend that spread footings be sized based on an allowable bearing pressure of 2,500 psf. This is a net bearing pressure; the weight of the footing and overlying backfill can be ignored in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead and long-term live loads and may be increased by 50 percent for short-term loads, such as those resulting from wind or seismic forces.


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 lowest adjacent grade. Interior footings should be founded at least 12 inches below the base of the floor slab. 7.2.2 Lateral Resistance Lateral loads on footings can be resisted by the 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 native soil and structural fill is 350 pcf, modeled as an equivalent fluid pressure. Adjacent floor slabs, pavements, or the upper 12-inch depth of adjacent unpaved areas should not be considered when calculating passive resistance. A coefficient of friction equal to 0.35 may be used when calculating resistance to sliding for footings in direct contact with the native sand. Footings in contact with crushed rock should be designed using a coefficient of friction of 0.40. 7.2.3 Settlement We anticipate that the total post-construction settlement of the new building will be less than 1 inch for shallow foundations designed in accordance with the recommendations provided above. Differential settlement between similarly loaded footings is expected to be less than ½ inch. In our opinion, the foundation loads for the new building will cause settlement of the adjacent building footings on the west side of the site. We anticipate that total post-construction settlement beneath the adjacent buildings will be less than ½ inch. This additional settlement could result in damage to the adjacent buildings, such as the development of cracks in the building walls. The project structural engineer should evaluate whether the existing structures can tolerate settlements of these magnitudes. If these settlements cannot be tolerated, measures can be taken to reduce the amount of settlement, including underpinning the adjacent buildings, installing rammed aggregate piers beneath the new building, or installing the new building on a mat foundation. GeoDesign can provide recommendations for these mitigation measures if requested. 8.0 BASEMENT WALLS Permanent retaining structures should be designed to resist the earth pressures presented on Figure 1. These values are based on the assumption that (1) the retained soil is level, (2) the backfill consists of granular material, and (3) that groundwater remains below the basement. Lateral pressures induced by surcharge loads can be computed using the methods presented on Figure 2. Seismic lateral forces can be calculated using a uniformly distributed pressure equal to 7H pounds per linear foot of wall, where H is the wall height. Lateral loads on footings can be resisted by passive earth pressure on the sides of the buried structure and by friction along the base of the mat. The available passive earth pressure is 350 pcf modeled as an equivalent fluid pressure. The upper 12 inches of adjacent unpaved


areas should not be considered when calculating passive resistance. An ultimate coefficient of friction value equal to 0.40 may be used when calculating resistance to sliding for foundations bearing on gravel. 9.0 SEISMIC DESIGN CRITERIA Appendix B presents a site-specific seismic study that includes seismic design parameters for the proposed development. 10.0 OBSERVATION OF CONSTRUCTION Satisfactory earthwork and foundation performance depends to a large degree on the quality of construction. Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect whether subsurface conditions change significantly from those anticipated. In addition, sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. 11.0 LIMITATIONS We have prepared this report for use by Core Campus LLC and their consultants. The data and report can be used for estimating purposes, but our report, conclusions, and interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Soil explorations indicate soil conditions only at specific locations and only to the depths penetrated. They do not necessarily reflect soil strata or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during the course of excavation and construction, re-evaluation will be necessary. The site development plans and design details were not finalized at the time this report was prepared. When the design has been finalized and if there are changes in the site grades or location, configuration, design loads or type of construction for the buildings, the conclusions and recommendations presented may not be applicable. If design changes are made, we should be retained to review our conclusions and recommendations and to provide a written evaluation or modification. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with the generally accepted practices in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood.


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, GeoDesign, Inc. Brett A. Shipton, P.E., G.E. Principal Engineer


REFERENCES Beeson, M.H., Tolan, T.L., and Madin, I.P., 1991, Geologic Map of the Portland Quadrangle, Multnomah and Washington Counties, Oregon, and Clark County, Washington. Oregon Department of Geology and Mineral Industries Geological Map GMS-75, scale 1:24,000. Gannett, Marshall W., and Caldwell, Rodney R., 1998, Geologic Framework of the Willamette Lowland Aquifer System, Oregon and Washington, U.S. Geological Survey, Professional Paper 1424-A, 32 p., 8 plates. Madin, Ian P., 1990, Earthquake-Hazard Geology Maps of the Portland Metropolitan Area, Oregon: Text and Map Explanation, Oregon Department of Geology and Mineral Industries, Open-File Report O-90-2, 21p., 8 plates. Post Tensioning Institute, 2014. Recommendations for Prestressed Rock and Soil Anchors. Pratt, T.L., et al., 2001, Late Pleistocene and Holocene Tectonics of the Portland Basin, Oregon and Washington, from High-Resolution Seismic Profiling, Bulletin of the Seismological Society of America, 91, pp. 637-650.

FIGURES

DESIGNPRESSURE

RECOMMENDED DESIGN PARAMETERSFOR BRACED WALLS

EXPLANATION:

PP = 350 H2 PCF SILT (ABOVE GROUNDWATER)PP = 180 H3 PCF SILT (BELOW GROUNDWATER)H1 = DEPTH OF SOLDIER PILE EXPOSED HEIGHT IN FEETH2+H3 = SOLDIER PILE EMBEDMENT DEPTH IN FEETPASSIVE PRESSURE ACTS OVER 3X THE PILE WIDTH.ACTIVE PRESSURE ACTS OVER 1X THE PILE WIDTH BELOW THE EXCAVATION BASE.

NOTES:1. DOES NOT INCLUDE SURCHARGE OR SEISMIC LOADS.2. TIEBACKS SHOULD BE LOCKED OFF AT 100 PERCENT OF DESIGN LOAD.3. THE LATERAL EARTH PRESSURES ARE UNFACTORED.4. PASSIVE PRESSURE RESISTANCE SHOULD BE NEGLECTED 2 FEET BELOW THE BOTTOM OF THE EXCAVATION.

H1

30°'

H2

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EMBEDMENT

UNBONDED ZONEFOR ANCHORS

Pa = 35H1

Pa = 35(H1 + H2)

0.2H1

0.6H1

0.2H1

25H1PSF

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Pa = 35(H1 + H2) + 80H3

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2.

THESE GUIDELINES APPLY TO RIGID WALLS WITH POISSON'S RATIO ASSUMED TO BE 0.5 FOR BACKFILL MATERIALS.

LATERAL PRESSURES FROM ANY COMBINATION OF ABOVE LOADS MAY BE DETERMINED BY THE PRINCIPLE OF SUPERPOSITION.

3. VALUES IN THIS FIGURE ARE UNFACTORED.

Off 503.968.8787 Fax 503.968.3068

Portland OR 97224


Printed By: aday | Print Date: 6/13/2016 1:49:31 PM

File Name: J:\A-D\CoreCampus\CoreCampus-3\CoreCampus-3-01\Figures\CAD\CoreCampus-3-01-DET02.dwg | Layout: FIGURE 2

SURCHARGE-INDUCED LATERAL EARTH PRESSURESCORECAMPUS-3-01

FIGURE 2JUNE 2016PROPOSED PORTLAND CAMPUS DEVELOPMENT

PORTLAND, OR

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APPENDIX A

A-1 CoreCampus-3-01:062016

APPENDIX A PRIOR EXPLORATIONS This appendix presents logs of borings drilled by Krazan & Associates, Inc. for the proposed development.

Project Number: 062-14013

& A S S O C I A T E S, I N C.

Date: July 2015

Drawn By: JGL Figure 2

Site Plan(Not to Scale)

Portland Campus, 325 & 333 SW Harrison St., Portland, OR

Not to scale

B-1

B-1B-1

B-1

Number and Approximate Location of Soil Boring


Number and ApproximateLocation of Hand Tool Exploration

Approximate Elevation Contour (Feet)


Approximate Elevation Contour (Feet)


LEGEND

LEGEND LEGEND

LEGEND

Reference: The Site Plan is based on a drawing prepared by Centerline Concepts Land Surveying, in conjunction with Partner Engineering and Science, Inc., titled “Topographic Survey - Located in the S.W. 1/4 Section 3, T.1S., R.1E., W.M., City of Portland, Multnomah County, Oregon,” dated October 20, 2014. The Site Plan is also based on a U.S.G.S. topographic map and aerial photo titled, “Portland Quadrangle - Oregon-Washington - 7.5-Minute Series, dated 2014.

H-1

70

70

520

SW Harrison Street

SW

4th

Ave

nue

70

60

50

65

55

312

320

318

306

308

306

304

302

300

314

294

296

ApproximateSite Boundary

Ballinger Way N

E

19th

Ave

NE

ProposedApartmentBuilding

ExistingRockery Wall

Access and Utility Easement

NeighboringParcel Line

Access and Utility Easement

Possible PermeablePavement Area

ExistingCommercialBuilding

ExistingApartment Building

ExistingApartmentBuilding

ExistingBuilding

Approximate Site Area

ExistingBuilding

ExistingBuilding

ExistingBuilding

ExistingCarport Structure

39th Street

Alle

y

Approximate Existing RetainingWall Along EasternSite Boundary(Approximately 8 Ft - 10 Ft Tall)

Approximate Property Line

Parcel 1

Site Area (Parcels 1 and 2)

Light Rail Line

Parcel 2

B-1

B-2

B-3

B-1

B-2 B-3

B-2

B-1

H-2

H-1

Appendix A Page A.1

APPENDIX A

FIELD INVESTIGATION – LABORATORY TESTING

Field Investigation

The field investigation consisted of a surface reconnaissance and a subsurface exploration program. Three (3) exploratory soil borings were drilled and sampled for the subsurface investigation at this site. The soil borings were completed on June 11, 2015 through June 12, 2015 by a Krazan subcontractor utilizing a truck-mounted drill rig. The soil borings were advanced to depths ranging from 26.5 to 90.5 feet BGS. The approximate exploratory boring locations are shown on the Site Plan (Figure 2). The depths shown on the attached boring logs are from the existing ground surface at the time of our exploration.

The drilled borings were advanced using a truck mounted drilling rig. Soil samples were obtained by using the Standard Penetration Test (SPT) as described in ASTM Test Method D1586. The Standard Penetration Test and sampling method consists of driving a standard 2-inch outside-diameter, split barrel sampler into the subsoil with a 140-pound hammer free falling a vertical distance of 30 inches. The summation of hammer-blows required to drive the sampler the final 12-inches of an 18-inch sample interval is defined as the Standard Penetration Resistance, or N-value. The blow count is presented graphically on the boring log in this appendix. The resistance, or “N” value, provides a measure of the relative density of granular soils or of the relative consistency of cohesive soils.

The soils encountered were logged in the field during the exploration are described in accordance with the Unified Soil Classification System (USCS). All samples were returned to a Krazan laboratory for evaluation. The log of the soil explorations are presented in this appendix.

Laboratory Testing

The laboratory testing program was developed primarily to determine the index and engineering properties of the soils. Test results were used for soil classification and as criteria for determining the engineering suitability of the subsurface materials encountered.

Project Number: 062-14013

& A S S O C I A T E S, I N C.

Date: July 2015

Drawn By: VC

References: USCS

Soil Classification

Portland Campus, Portland, OR

Relative Density with Respect to SPT N-Value

Coarse-Grained Soils

Density

Very Loose Very Soft

Soft

Medium Stiff

Stiff

Very Stiff

Hard

0 - 4 0 - 1

2 - 4

5 - 8

9 - 15

16 - 30

> 30

5 -10

11 - 30

31 - 50

> 50

Loose

Medium Dense

Dense

Very Dense

DensityN-Value (Blows/Ft) N-Value (Blows/Ft)

Fine-Grained Soils

USCS Soil Classification

Major Division

Coarse-Grained Soils

< 50% passes #200 sieve

Gravel andGravelly Soils< 50% coarsefraction passes#4 sieve

Gravel(with little or no fines)

GW Well-Graded Gravel

Poorly Graded Gravel

Silty Gravel

Clayey Gravel

Well-Graded Sand

Poorly Graded Sand

Silty Sand

Clayey Sand

Silt

Lean Clay

Organic Silt and Clay (Low Plasticity)

Inorganic Silt

Inorganic Clay

Organic Clay and Silt (Med. to High Plasticity)

Peat

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

Sand(with little or no fines)

Gravel(with > 12% fines)

Sand(with > 12% fines)

Sand andSandy Soils> 50% coarsefraction passes#4 sieve

Silt and ClayLiquid Limit < 50

Silt and ClayLiquid Limit > 50

Highly Organic Soils

Fine-Grained Soils

> 50% passes #200 sieve

Group Description

LOG OF EXPLORATORY BORINGPROJECT:

PROJECT NO.:

BORING TYPE:

PAGE: 1 of 3

DATE:

SURFACE ELEVATION:

CONTRACTOR:

SAMPLE METHOD: LOCATION:

LOGGED BY:

Water Observations:

Notes:

KRAZAN & ASSOCIATES922 Valley Avenue NW

Suite 101Puyallup, Washington 98371

DE

PT

H (

ft)

5

10

15

20

25

30

US

C

WA

TE

R L

EV

EL

MATERIAL DESCRIPTIONBLOW

COUNTS(per 6")

N-VALUE(Last 12"of SPT)

SA

MP

LE

S

RE

CO

VE

RY

N-Value (GRAPH)

10 20 30 40 50Natural Moisture

Content

(percent)10 20 30 40

Water Level Initial: # Final: $

B-1Portland Campus

062-14013

Mud-Rotrary

6-12-15

~120 feet

Subsurface Tech.

SPT, Split-Spoon Portland, OR

VC

~3.5" Asphalt

Fill

Crushed rock, and gray to brown silty sand. (moist)

Silty Sand (SM)

Gray to brown silty sand. (loose to medium dense, moist)

- Soil becomes medium dense

91212

222

233

448

88

10

61010

24

4

6

12

18

20

16"

16"

12"

10"

15"

10"

Groundwater seepage was not encountered.


PROJECT NO.:

BORING TYPE:

PAGE: 2 of 3

DATE:

SURFACE ELEVATION:

CONTRACTOR:


LOGGED BY:

Water Observations:

Notes:



DE

PT

H (

ft)

36

41

46

51

56

61

US

C

WA

TE

R L

EV

EL


COUNTS(per 6")


SA

MP

LE

S

RE

CO

VE

RY

N-Value (GRAPH)


Content

(percent)10 20 30 40


B-1Portland Campus

062-14013

Mud-Rotrary

6-12-15

~120 feet

Subsurface Tech.


VC

Sand with Silt (SP-SM))

Gray to brown, fine to coarse sand with silt. (medium dense, moist)

Silty Sand (SM)

Brown silty sand. (loose to medium dense, moist)

- Soil becomes dense

7911

111112

131515

101213

101215

161617

20

23

30

25

27

33

12"

14"

13"

17"

16"

15"



PROJECT NO.:

BORING TYPE:

PAGE: 3 of 3

DATE:

SURFACE ELEVATION:

CONTRACTOR:


LOGGED BY:

Water Observations:

Notes:



DE

PT

H (

ft)

68

73

78

83

88

93

US

C

WA

TE

R L

EV

EL


COUNTS(per 6")


SA

MP

LE

S

RE

CO

VE

RY

N-Value (GRAPH)


Content

(percent)10 20 30 40


B-1Portland Campus

062-14013

Mud-Rotrary

6-12-15

~120 feet

Subsurface Tech.


VC

Sand with Silt (SP-SM)

Gray to brown, fine to medium sand with silt. (dense, moist)

Gravel with Sand and Silt (GP-GM)

Gray to brown gravel with sand and silt. (very dense, moist)

End of Exploratory Boring

151519

181820

131418

141516

2050(4")

34

38

32

31

50+

11"

14"

12"

18"

6"


LOG OF EXPLORATORY BORINGPROJECT:PROJECT NO.:

BORING TYPE:

PAGE: 1 of 1DATE:

SURFACE ELEVATION:CONTRACTOR:SAMPLE METHOD: LOCATION:

LOGGED BY:

Water Observations:

Notes:



DEP

TH (f

t)

5

10

15

20

25

30

USC

WA

TER

LEV

EL


COUNTS(per 6")


SAM

PLES

REC

OVE

RY

N-Value (GRAPH)10 20 30 40 50

Natural MoistureContent

(percent)10 20 30 40


B-2Portland Campus

06214014

HSA

6-12-15

~122 feetSubsurface Tech.


VC

~3" AsphaltFill

Crushed rock and brown silty sand with gravel. (moist)

Silty Sand (SM)

Brown, silty sand. (dry to moist, loose to medium dense)

- becomes gray to brown and medium dense below 20.0 feet.


455

455

334

366

368

10

10

7

12

14

12"

7"

18"

16"

18"



BORING TYPE:

DATE: 6-12-15 PAGE: 1 of 3


LOGGED BY:

Water Observations:

Notes:



DEP

TH (f

t)

5

10

15

20

25

30

USC

WA

TER

LEV

EL


COUNTS(per 6")


SAM

PLES

REC

OVE

RY

N-Value (GRAPH)10 20 30 40 50


(percent)10 20 30 40


B-3Portland Campus

062-14014

Mud Rotrary~127 feet

Subsurface Tech.SPT, Split-Spoon Portland, OR

VC

~4" AsphaltFill

Crushed rock, and gray to brown silty sand. (moist)

Silty Sand (SM)

Gray to brown silty sand. (loose, moist)

Sandy Silt (ML)

Gray to brown sandy silt. (medium stiff, moist)

334

454

333

645

61114

747

7

9

6

9

25

11

6"

10"

12"

10"

14"

12"


Per Driller gravel encountered at 86.5 feet.

Silty Sand (SM)

Gray to brown silty sand. (loose to medium dense, moist to wet)


BORING TYPE:

PAGE: 2 of 3DATE:


LOGGED BY:

Water Observations:

Notes:



DEP

TH (f

t)

37

42

47

52

57

62

USC

WA

TER

LEV

EL


COUNTS(per 6")


SAM

PLES

REC

OVE

RY

N-Value (GRAPH)10 20 30 40 50


(percent)10 20 30 40


B-3Portland Campus

062-14014

Mud Rotrary

6-12-15



VC

- Soil becomes moist to wet and dense at 45.0 feet.

Sand (SP)

Gray to brown fine to coarse sand. (dense to very dense, moist)

13810

81113

101418

233126

142224

151616

18

24

32

57

46

32

9"

15"

12"

16"

15"

16"




BORING TYPE:

PAGE: 3 of 3DATE:


LOGGED BY:

Water Observations:

Notes:



DEP

TH (f

t)

69

74

79

84

89

94

USC

WA

TER

LEV

EL


COUNTS(per 6")


SAM

PLES

REC

OVE

RY

N-Value (GRAPH)10 20 30 40 50


(percent)10 20 30 40


B-3Portland Campus

062-14014

Mud Rotrary

6-12-15



VC

Silty Sand (SM)

Gray to brown silty sand. (medium dense to very dense, moist)

Sand (SP)

Gray to brown fine to coarse sand. (very dense, moist)

Gravel with Sand (GP)

Gray gravel with sand. (very dense, moist)


191619

252022

151416

222530

232729

50(4")

35

42

30

55

56

50+

12"

12"

13"

15"

16"

4"



(no specification provided)*

PL= LL= PI=

USCS (D 2487)= AASHTO (M 145)=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

Remarks

Silty sand.Sampled by V.Chaudhary.

#4#8#16#20#40#60#80

#100#200

100.096.491.089.585.483.178.574.347.5

NP NV NP

SM A-4(0)

0.9454 0.3820 0.10020.0794

Sample ID:15L324Sample Date:6-11-15

6-11-15 6-29-15

J.Martin

M.Thomas

Materials Laboratory Manager

6-11-15

Partner Engineering

Portland Campus

062-14013

Material Description

Atterberg Limits (ASTM D 4318)

Classification

Coefficients

Date Received: Date Tested:

Tested By:

Checked By:

Title:

Date Sampled:Location: B-1Sample Number: 15L324 Depth: 15'-16.5'

Client:

Project:

Project No: Figure

Test Results (C-136 & C-117)

Opening Percent Spec.* Pass?

Size Finer (Percent) (X=Fail)

PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +3"Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.0 4.9 9.7 37.9 47.5

6 in

.

3 in

.

2 in

.

1½

in.

1 in

.

¾ in

.

½ in

.

3/8

in.

#4

#1

0

#2

0

#3

0

#4

0

#6

0

#1

00

#1

40

#2

00

Particle Size Distribution Report


PL= LL= PI=


D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

Remarks

Silty sand.Sampled by V.Chaudhary

#4#8#10#16#20#40#60#80

#100#200

100.097.495.590.988.480.070.159.151.931.0

NP NV NP

SM A-2-4(0)

1.0426 0.6159 0.18420.1425

Sample ID:15L335Sample Recieved:6-11-15

6-11-15 6-29-15

J.Martin

M.Thomas


6-11-15

Partner Engineering

Portland Campus

062-14013



Classification

Coefficients


Tested By:

Checked By:

Title:


Client:

Project:

Project No: Figure




PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +3"Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.0 4.5 15.5 49.0 31.0

6 in

.

3 in

.

2 in

.

1½

in.

1 in

.

¾ in

.

½ in

.

3/8

in.

#4

#1

0

#2

0

#3

0

#4

0

#6

0

#1

00

#1

40

#2

00



PL= LL= PI=


D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

Remarks

Silty sand.Sampled by V.Chaudhary.

#4#8#10#16#20#40#60#80

#100#200

100.094.691.786.383.672.556.141.535.621.7

NP NV NP

SM A-2-4(0)

1.7810 0.9927 0.27570.2187 0.1189

Sample ID:15L325Sample Date:6-12-15

6-12-15 6-29-15

J.Martin

M.Thomas


6-12-15

Partner Engineering

Portland Campus

062-14013



Classification

Coefficients


Tested By:

Checked By:

Title:


Client:

Project:

Project No: Figure




PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +3"Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.0 8.3 19.2 50.8 21.7

6 in

.

3 in

.

2 in

.

1½

in.

1 in

.

¾ in

.

½ in

.

3/8

in.

#4

#1

0

#2

0

#3

0

#4

0

#6

0

#1

00

#1

40

#2

00


APPENDIX B

B-1 CoreCampus-3-01:062016

APPENDIX B SITE-SPECIFIC SEISMIC HAZARD EVALUATION INTRODUCTION The information in this appendix summarizes the results of a site-specific seismic hazard study for the proposed located northeast of the intersection of SW 14th Avenue and SW Harrison Street in Portland, Oregon. The proposed development is 15-story building with four levels below grade. The basement extends to a depth of approximately 50 feet below existing site grades. This seismic hazard evaluation was performed in accordance with the requirements in the 2014 SOSSC and ASCE 7-10. SITE CONDITIONS REGIONAL GEOLOGY The site is located in the western portion of the Portland Basin physiographic province, which is bound by the Tualatin Mountains to the west and south and the Cascade Range to the east and north. The Portland Basin is described as a fault-bounded, pull-apart basin that was formed by two northwest-trending fault zones (Pratt et al., 2001). The Portland Hills fault zone trends along the west side of the basin and the Frontal fault zone trends along the east side of the basin near Lacamas Lake, east of Vancouver, Washington. A review of published geologic literature and previous explorations in the area indicates the site is underlain by Quaternary flood deposits (Gannet and Caldwell, 1998; Beeson et al., 1991; and Madin, 1990), delineated as the fine-grained facies (Qff). The unit consists of unconsolidated coarse sand to silt with occasional clayey layers. The unit was deposited by multiple catastrophic glacial floods associated with the late Pleistocene (15,500 to 13,000 years before present) Missoula Floods. Thickness of the flood deposits in the site vicinity is approximately 30 to 60 feet. Underlying the flood deposits is the Pliocene to Pleistocene Age (5 million to 1.5 million years before present) Troutdale Formation (QTg), which consists of poorly to moderately consolidated, semi-cemented, subrounded to rounded sand and gravel. The thickness of the Troutdale Formation in the site vicinity is approximately 100 to 150 feet (Gannet and Caldwell, 1998; Beeson et al., 1991; and Madin, 1990). The Troutdale Formation is underlain by the Miocene Age (20 million to 10 million years before present) CRBG (Tcr), which is a series of basalt flows that originated from southeastern Washington and northeastern Oregon. The CRBG is several hundred feet thick and considered the geologic basement unit for this report. SUBSURFACE CONDITIONS A detailed description of site subsurface conditions is presented in the main report.


SEISMIC SETTING 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 suggesting that 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 Washington Coast. Two types of subduction zone earthquakes are possible and considered in this study: 1. An interface event earthquake on the seismogenic 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 intraplate earthquake on the seismogenic part of the subducting 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 A significant earthquake could occur on a local fault near the site within the design life of the facility. Such an event would cause ground shaking at the site that could be more intense than the CSZ events, though the duration would be shorter. Figure B-1 shows the locations of faults with potential Quaternary movement within a 20-mile radius of the site. Figure B-2 shows the interpreted locations of seismic events that occurred between 1833 and 1993 (Johnson et al., 1994). Table B-1 presents the relative distance, displacement, and estimated age of the crustal faults that may present a hazard to the site. The three most critical faults in the site vicinity are the Portland Hills, East Bank, and Oatfield faults. The nearest potentially active, and therefore most significant, fault is the Portland Hills fault inferred at a distance of less than 1 km south of the site.


Table B-1. Faults within the Site Vicinity

Fault Name Proximity

to Site (km)

Estimated Displacement Description Estimated Age

Portland Hills

0.3 Potential offset of Missoula flood deposits by means of geophysical techniques and trench excavation.

Late Quaternary (< 15,000 years before present)

East Bank 2.8 Probable offset of unconformities and paleochannels associated with the Missoula flood deposits.

Late Quaternary (< 15,000 years before present)

Oatfield 3.7 Offsets Columbia River Basalt flows and overlying fluvial and lacustrine deposits. Does not offset Missoula flood deposits.

Quaternary (< 1.6 million years

before present) SITE RESPONSE ANALYSIS RISK TARGETED BEDROCK SPECTRUM We obtained a probabilistic bedrock spectrum for the site from the USGS national seismic mapping project. We determined the spectral accelerations for the outcropping bedrock response spectrum for periods ranging from 0 to 5 seconds. The response spectrum is consistent with a shear wave velocity equal to 760 meters per second in the upper 30 meters of the soil profile. ASCE 7-10 requires that the ground motions be defined in terms of the maximum direction of horizontal response. The maximum direction was adopted as the ground motion intensity parameter for use in lieu of explicit consideration of directional effects. The maximum horizontal response may reasonably be estimated by factoring the average response period by period dependent factors. The commentary to ASCE 7-10 recommends a factor of 1.1 at short periods and 1.3 at a period of 1 second and greater. The risk targeted bedrock spectrum, MCE

R, target bedrock spectrum was computed using

Method 2 outlined in the ASCE 7-10 Section 21.2.1.2. A risk coefficient of CRS = 0.901 was

applied to the spectrum at periods of 0.2 second or less and a risk coefficient of CR1 = 0.875 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. Table B-2 presents a summary of values used to compute the MCE

R target bedrock response spectrum.


Table B-2. Risk Targeted Bedrock Spectrum

Period (seconds)

MCE Bedrock Spectral

Acceleration (g)

Maximum Direction Factor

CR

MCER Target

Bedrock Spectral Acceleration

(g)

0.0 0.440 1.1 0.902 0.437

0.1 0.918 1.1 0.902 0.911

0.2 1.020 1.1 0.902 1.012

0.3 0.876 1.1 0.899 0.866

0.5 0.673 1.1 0.892 0.661

1.0 0.381 1.3 0.875 0.434

2.0 0.193 1.3 0.875 0.220

3.0 0.106 1.3 0.875 0.121

4.0 0.069 1.3 0.875 0.078

5.0 0.043 1.3 0.875 0.048 BASE GROUND MOTIONS Six recorded base ground motions were selected to represent the local seismic setting. We considered faulting mechanism, magnitude, and distance to recording station. Ground motions at the site are controlled by a crustal event and the CSZ interface event. We selected three acceleration time histories to represent each of these seismic sources as input for the seismic response analysis. Table B-3 provides the ground motions selected for this study.

Table B-3. Selected Ground Motions

Ground Motion/Recording Station Magnitude Distance

(km) Component

Crustal Records

Whittier Narrows 1987/Mt. Wilson 5.9 19 00

North Palm Springs 1986/Desert Hot Springs 6.0 10 00

Imperial Valley 1979/Cerro Prieto 6.5 25 147

Subduction Zone Records

Valparaiso 1985/Pichilemu 7.8 80 90

Michoacan 1985/La Union 8.0 84 N00W

Michoacan 1985/Zihuatanejo 8.0 130 N90W SITE CONDITION MODELING We determined acceleration response spectra for the postulated scenarios discussed above by performing a site-specific seismic response analysis. An equivalent linear seismic response analysis as described in ASCE 7-10 Section 21.1.2. The site response analysis was performed using the SHAKE 91+ module of the EZ-FRISK 7.80 software package.


Soil Model The input soil model used in our analysis is based on the findings of the subsurface exploration program. A detailed description of site subsurface conditions is provided in the main report. Table B-4 provides a summary of the soil model used in our analysis. The acceleration response spectra produced by our equivalent linear seismic response analysis is presented on Figure B-3.

Table B-4. Input Soil Profile

Depth Interval (feet)

Subsurface Unit

Shear Wave Velocity

(feet per second)

Modulus Reduction Curve

Damping Curve

0 to 501 Sand 900 Seed & Idriss,

1970 Seed & Idriss,

1970

30 to 80 Sand 1,000 to 1,200 Seed & Idriss,

1970 Seed & Idriss,

1970

80 to 1502 Gravel 1,600 to 2,300 Seed & Idriss,

1970 Seed & Idriss,

1970 1. Output ground motion at the ground surface and at a depth of 50 feet BGS 2. Ground motions input at the base of this layer

DETERMINISTIC MCE

R RESPONSE SPECTRUM

The deterministic approach considers the maximum ground acceleration that may occur at the site as a result of a characteristic earthquake on all known active faults in the region. ASCE 7-10 Section 21.2.2 requires that the spectral response at each period be calculated as an 84th percentile 5 percent damped spectral response acceleration in the direction of maximum horizontal response. However, the lower limit is computed in accordance with Figure 21.2-1 in ASCE 7-10 where F

a and F

v are determined using Tables 11.4-1 and 11.4-2 in ASCE 7-10.

Figure B-4 shows the deterministic lower limit as prescribed by ASCE 7-10 Section 21.2.2. SITE-SPECIFIC MCE

R RESPONSE SPECTRUM

As outlined in ASCE 7-10 Section 21.2.3, the site-specific MCER shall be taken as the lesser of the

probabilistic MCER and the deterministic MCE

R. Figure B-4 shows the site-specific design

response spectrum. The site-specific response spectrum presented on Figure B-3 is the envelope of the output spectra at the ground surface and at a depth of 50 feet BGS. DESIGN RESPONSE SPECTRUM ASCE 7-10 Section 21.3 states that the site-specific MCE

R 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 7-10 Section 11.4.5. DESIGN ACCELERATION PARAMETERS To develop the final design response spectrum, the lesser of the values obtained from the probabilistic MCE and the deterministic MCE are taken at each period. The parameter S

DS is taken

from the site-specific response spectrum at a period of 0.2 second but shall not be smaller than 90 percent of the peak spectral acceleration taken at any period larger than 0.2 second. The


parameter SD1

is taken as the greater of the spectral acceleration at 1 second or two times the acceleration at 2 seconds. Figure B-5 shows the design response spectrum. 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, landsliding, and fault rupture. The following sections provide additional discussion regarding potential seismic hazards that could affect the planned recreation facility. SURFACE FAULT RUPTURE The Portland Hills fault is mapped 0.3 km from the site (Beeson et al., 1991; Madin, 1990). The mapped location is based on limited deep borehole data and geophysical data showing offset of the Troutdale Formation and the Columbia River Basalt in the Portland Basin and is not considered to accurately represent the fault location. Consequently, it is our opinion that the probability of surface fault rupture beneath the site is low. LIQUEFACTION 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 pressure can dissipate. In general, loose, saturated sand soil with low silt and clay content is the most susceptible to liquefaction. Soil susceptible to liquefaction was not encountered in the explorations. Consequently, liquefaction is not considered a site hazard. LATERAL SPREADING The site is located approximately 1 km from the west bank of the Willamette River. Based on this and the fact that liquefaction is not expected, the site is not susceptible to lateral spreading under design levels of ground shaking. GROUND MOTION 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 using the levels of ground shaking prescribed by ASCE 7-10. LANDSLIDE Earthquake-induced landsliding generally occurs in steeper slopes comprised of relatively weak soil deposits. The site and surrounding area are relatively flat, and landslides are unlikely during postulated seismic scenarios.


SETTLEMENT Settlement due to earthquakes is most prevalent in relatively deep deposits of dry, clean sand. We do not anticipate that significant settlement in addition to liquefaction-induced 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 B-3 are below the threshold required to induce lurching of the site soil. SEICHE AND TSUNAMI The site is inland and elevated away from tsunami inundation zones and away from large bodies of water that may develop seiches. Seiches and tsunamis are not considered a hazard in the site vicinity. REFERENCES Abrahamson, Norman and Silva, Walter, 2008, Summary of the Abrahamson & Silva NGA Ground-Motion Relations Earthquake Spectra, Volume 24, No. 1, pages 67–97, February 2008;© 2008, Earthquake Engineering Research Institute Allen, J.E., Burns, M., and Sargent, S., 1986, Cataclysms on the Columbia: Timber Press, Portland: 211 p. Beeson, M.H., Tolan, T.L., and Madin, I.P., 1991, Geologic Map of the Portland Quadrangle, Multnomah and Washington Counties, Oregon, and Clark County, Washington. Oregon Department of Geology and Mineral Industries Geological Map GMS-75, scale 1:24,000. Burns, Scott, 1998. Geologic and physiographic provinces of Oregon: p 3-14 in Scott Burns, editor, Environmental, Groundwater and Engineering Geology: Applications from Oregon. Association of Engineering Geologists, Special Publication 11: 689 p. Burns, Scott, Growney, Lawrence, Brodersen, Brett, Yeats, Robert S., Popowski, Thomas A., 1997, Map showing faults, bedrock geology, and sediment thickness of the western half of the Oregon City 1:100,000 quadrangle, Washington, Multnomah, Clackamas, and Marion Counties, Oregon, Oregon Department of Geology and Mineral Industries, IMS-4, scale 1:100,000.


Gannett, Marshall W., and Caldwell, Rodney R., 1998, Geologic Framework of the Willamette Lowland Aquifer System, Oregon and Washington, U. S. Geological Survey, Professional Paper 1424-A, 32 p., 8 plates. Johnson, A.J., Scofield, D.H., and Madin, I.P., 1994, Earthquake Database for Oregon, 1833-October 25, 1993, Oregon Department of Geology and Mineral Industries, Open-File Report O-94-04. Ma, Lina, Madin, Ian P., Olson, Keith V., Watzig, Rudie J., compilers, 2009, Oregon Geologic Data Compilation, Version 5, Oregon Department of Geology and Mineral Industries, ODGB-5, GIS digital data. Mabey, M. A., et al., 1993, Earthquake Hazard Maps of the Portland Quadrangle, Multnomah and Washington Counties, Oregon, and Clark County, Washington, Oregon Department of Geology and Mineral Industries, GMS-79, scale 1:24,000. Madin, Ian P., 1990, Earthquake-Hazard Geology Maps of the Portland Metropolitan Area, Oregon: Text and Map Explanation, Oregon Department of Geology and Mineral Industries, Open-File Report O-90-2, 21p., 8 plates. Oregon Structural Specialty Code, Volume 2, 2014, International Conference of Building Codes. Orr, E.L. and Orr, W.N., 1999, Geology of Oregon. Kendall/Hunt Publishing, Iowa: 254 p. Personius, S.F., compiler, 2002, Quaternary fault and fold database of the United States, ver. 1.0: U.S. Geological Survey Open-File Report 03-417, http://qfaults.cr.usgs.gov. Pratt, T.L., et al., 2001, Late Pleistocene and Holocene Tectonics of the Portland Basin, Oregon and Washington, from High-Resolution Seismic Profiling, Bulletin of the Seismological Society of America, 91, pp. 637-650. U.S. Geologic Survey, 2002, United States Earthquake Hazard Program, United States National Seismic Hazard Maps, 2002 Database, http://earthquake.usgs.gov/research/hazmaps/ Weaver, C.S. and Shedlock, K.M., 1991, Program for earthquake hazards assessment in the Pacific Northwest: U.S. Geological Survey Circular 1067, 29 pgs


Portland OR 97224 Off 503.968.8787 Fax 503.968.3068

CORECAMPUS-3-01 QUATERNARY FAULT MAP

JUNE 2016 PROPOSED PORTLAND CAMPUS DEVELOPMENT

PORTLAND, OR FIGURE B-1

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CORECAMPUS-3-01 HISTORICAL SEISMICITY MAP



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CORECAMPUS-3-01 SITE RESPONSE SPECTRA



CoreCampus-3-01-FB3_B5.docx Print Date: 6/13/16



CORECAMPUS-3-01 SITE-SPECIFIC RESPONSE SPECTRA






CORECAMPUS-3-01 DESIGN RESPONSE SPECTRUM




ACRONYMS AND ABBREVIATIONS

CoreCampus-3-01:062016

ACRONYMS AND ABBREVIATIONS AC asphalt concrete ASCE American Society of Civil Engineers ASTM American Society for Testing and Materials BGS below ground surface CRBG Columbia River Basalt Group CSZ Cascadia Subduction Zone g gravitational acceleration (32.2 feet/second2) H:V horizontal to vertical km kilometers ksf kips per square foot MCE maximum considered earthquake MCE

R risk targeted maximum considered earthquake

OSHA Occupational Safety and Health Administration pcf pounds per cubic foot pci pounds per cubic inch psf pounds per square foot SOSSC State of Oregon Structural Specialty Code SPT standard penetration test USGS U.S. Geological Survey

REPORT OF GEOTECHNICAL ENGINEERING SERVICES · PDF fileREPORT OF GEOTECHNICAL ENGINEERING SERVICES Proposed Portland Campus Development 325 and 333 SW Harrison Street Portland, Oregon

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