308 and 310 9th Avenue North Seattle, Washington

Geotechnical Report308 and 310 9th Avenue North

Seattle, Washington

March 15, 2016

Submitted To: Mr. Brian Regan

Equinox Properties Corp. 8 Boston Street, #1

Seattle, Washington 98109

By: Shannon & Wilson, Inc.

400 N 34th Street, Suite 100 Seattle, Washington 98103

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TABLE OF CONTENTS

Page

1.0 INTRODUCTION ..................................................................................................................1

2.0 SITE AND PROJECT DESCRIPTION .................................................................................1

3.0 REVIEW OF EXISTING INFORMATION ..........................................................................1

4.0 SUBSURFACE EXPLORATIONS .......................................................................................2

5.0 LABORATORY TESTING ...................................................................................................2

6.0 GEOLOGY AND SUBSURFACE CONDITIONS ...............................................................3 6.1 Regional Geology .......................................................................................................3 6.2 Site Geology ...............................................................................................................3 6.3 Groundwater ...............................................................................................................4

7.0 ENGINEERING CONCLUSIONS AND RECOMMENDATIONS ....................................4 7.1 General .......................................................................................................................4 7.2 Foundation Design .....................................................................................................4 7.3 Estimated Settlements ................................................................................................5 7.4 Seismic Design ...........................................................................................................5

7.4.1 Design Ground Motions ...............................................................................5 7.4.2 Earthquake-induced Geologic Hazards ........................................................6

7.5 Lateral Earth Pressures ...............................................................................................6 7.6 Lateral Resistance ......................................................................................................7 7.7 Base Footing Friction .................................................................................................7 7.8 Floor Slabs ..................................................................................................................7 7.9 Drainage .....................................................................................................................7 7.10 Temporary Soil Nail Shoring .....................................................................................8

8.0 CONSTRUCTION CONSIDERATIONS .............................................................................9 8.1 Fill Placement, Use of On-site Soils, and Compaction ..............................................9 8.2 Excavation Monitoring .............................................................................................10 8.3 Temporary Excavation Slopes .................................................................................11 8.4 Temporary Groundwater Control .............................................................................11 8.5 Wet Weather Earthwork ...........................................................................................11 8.6 Erosion Control ........................................................................................................12 8.7 Obstructions .............................................................................................................13

9.0 ADDITIONAL SERVICES .................................................................................................13

TABLE OF CONTENTS (cont.)

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10.0 LIMITATIONS ....................................................................................................................13

11.0 REFERENCES .....................................................................................................................16

TABLE

1 International Building Code 2012 Seismic Design Ground Motion Parameters .....6

FIGURES

1 Vicinity Map 2 Site and Exploration Plan 3 Recommended Surcharge Loading for Temporary and Permanent Walls 4 Typical Wall Drainage

APPENDICES

A Subsurface Explorations B Important Information About Your Geotechnical/Environmental Report

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GEOTECHNICAL REPORT 308 AND 310 9TH AVENUE NORTH

SEATTLE, WASHINGTON

1.0 INTRODUCTION

This report presents geotechnical engineering conclusions and recommendations for the proposed eight-story mixed-use building at 308 and 310 9th Avenue N, Seattle, Washington. This report includes a summary of the soil boring and geoprobe explorations (geoprobes), subsurface conditions, and the results of engineering studies and analyses. Our scope of services consisted of:

Performing a site reconnaissance; Drilling and soil sampling one soil boring and installing a monitoring well; Performing two geoprobes; and Performing laboratory testing, and preparing this report.

Our services were provided in general accordance with our proposal for geotechnical engineering services, dated February 10, 2016.

2.0 SITE AND PROJECT DESCRIPTION

We understand the project will be an eight-story mixed-use project with up to four levels of underground parking. The site is approximately 65 feet wide by 125 feet long. The site is bound by 9th Avenue N on the west, an alley to the east, a one-story brick commercial building to the north, and a parking lot to the south. There is a two-story building (Christian Science Reading Room) on the adjacent property to the south. There is a five-story building to the east of the alley. The location of the site is shown in the Vicinity Map, Figure 1. Surface elevation across the site is approximately 58 feet (City of Seattle Datum). The lowest parking level elevation is anticipated to be 18 feet with some footing excavations to elevation 12 feet. The depth of excavation will vary from about 40 to 45 feet.

3.0 REVIEW OF EXISTING INFORMATION

We reviewed seven subsurface exploration logs previously completed by other geotechnical consultants for other projects adjacent to the subject property. These consisted of logs from:

B46-1 (GeoEngineers, Inc., 2015) SW-2 (Shannon & Wilson, Inc., 2014)

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B-5 (GeoEngineers, Inc., 2002) B-1 – B-4 (GeoEngineers, Inc., 2001)

We used the factual subsurface information to aid in evaluating the subsurface conditions of the project site. The approximate locations of the borings are shown in the Site and Exploration Plan, Figure 2. The previous exploration logs are presented in Appendix A, Subsurface Explorations.

4.0 SUBSURFACE EXPLORATIONS

We performed a field reconnaissance on January 20, 2016, to observe site conditions, determine access for the drill rig, and select boring/geoprobe locations. On February 29, 2016, one boring, designated SW-1, was drilled and sampled. Two geoprobes, designated GP-1 and GP-2, were also advanced and sampled. The explorations were performed to generally characterize subsurface conditions across the site. The depth of the boring was 41.5 feet and a 2-inch monitoring well was installed after drilling. A description of the methodology and procedures used to located, drill, and sample the boring is discussed in Appendix A, Subsurface Explorations. The boring log is presented in Appendix A as Figure A-2. The approximate location of the boring is shown in the Site and Exploration Plan, Figure 2.

Geoprobes were advanced to 5.5 to 6 feet. A description of the methodology and procedures used to locate, advance, and sample the geoprobes is discussed in Appendix A, Subsurface Explorations. The geoprobe logs are presented in Appendix A as Figures A-3 and A-4. The approximate locations of the geoprobes are shown in the Site and Exploration Plan, Figure 2.

Screening was conducted onsite during drilling using a photoionization detector and olfactory methods. Hydrocarbon and/or volatile organic compounds odors were not observed in soil samples retrieved the explorations completed for this investigation.

5.0 LABORATORY TESTING

We performed geotechnical laboratory tests and visual classification on selected soil samples retrieved from the geotechnical boring. Our laboratory testing program consisted of determining natural water contents. Water content was determined on selected samples collected in general accordance with ASTM International (ASTM) D2216, Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock (ASTM, 2012). The exploration logs provided in Appendix A display measured water content of tested soil samples.

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6.0 GEOLOGY AND SUBSURFACE CONDITIONS

6.1 Regional Geology

The project is located in the central portion of the Puget Lowland, an elongated, north-south depression situated between the Olympic Mountains and the Cascade Range. Repeated glaciations in this region influenced the present-day topography, geology, and groundwater conditions in the project area.

Geologists generally agree that the Puget Lowland was subjected to six or more major glacial events, five of which may have overridden the Olympic area. Glacial ice from these glaciation originated in the Coast Range and Canadian Rockies, and generally flowed southward toward the Puget Lowland. Each glaciation deposited new sediment and partially eroded previous sediments. During the intervening periods, when glacial ice was not present, normal geomorphic processes, such as streams, wave action, and landsliding, eroded and reworked some of the glacially derived sediment.

During the most recent glaciations that covered the Puget Lowland (termed Vashon), glacial ice is estimated to have been about 3,000 feet thick in the projected area (Thorson, 1989). As the ice advanced southward, meltwater streams deposited sand and gravel (advance outwash). Beneath the glacier, an unstratified mixture of silt, sand, and gravel (glacial till) was deposited. The weight of the glacial ice compacted (overconsolidated) the glacial and nonglacial soil. Subglacial meltwater streams eroded into overconsolidated soil, forming valleys trending north-south.

As the Vashon glacier receded north, meltwater from the glacier deposited recessional glacial outwash and lacustrine sediments. The recessional glacial deposits are overlain by younger (Holocene-age), relatively loose and soft soil including alluvium and man-made fills.

6.2 Site Geology

Based on the subsurface conditions encountered during our exploration program, we interpret that the project area us underlain by a thin layer of recent fill underlain by a dense glacial till deposit. The soil units generally consist of:

Loose to medium dense, variable mixture of silty sand, gravel, and brick [Fill]; and

Dense to very dense, silty sand with gravel, and poorly graded sand with variable amounts of gravel [Glacial Deposits].

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The subsurface conditions, especially the fill thickness, vary across the building site. The subsurface explorations encountered the following generalized subsurface conditions:

The existing fill extends from ground surface down to about 6 feet below ground surface (bgs) under the southern portion of the building (308 9th Avenue N).

The fill is underlain by at least 35 feet of dense to very dense glacial till with discontinuous lenses of clean sand between 24 and 31 feet.

6.3 Groundwater

Groundwater was not encountered during drilling of boring SW-1. The GeoEngineers, Inc. (2001) report indicates groundwater around 37 feet bgs in boring B-3, located approximately 50 feet southeast of the subject property. The GeoEngineers, Inc. (2015) report indicates groundwater around 44 feet bgs in boring B46-1, located approximately 65 feet north of the subject property. We took a groundwater level reading on March 10, 2016, and groundwater was not observed in the well.

7.0 ENGINEERING CONCLUSIONS AND RECOMMENDATIONS

7.1 General

In general, the subject property is underlain by competent glacial soils that will provide good bearing for spread footing foundations and is well suited to a soil nail shoring system.

Engineering conclusions and recommendations are presented in the following sections for foundation design, estimated settlements, seismic criteria, lateral earth pressures, lateral resistance, base footing friction, floor slabs, subbdrainage, fill placement, excavated slopes, groundwater, wet weather earthwork, and temporary excavation support.

7.2 Foundation Design

Dense, glacially overridden soil encountered at the proposed excavation depth in the recent and adjacent borings is competent to support the anticipated building loads with conventional spread footings.

Foundations bearing in undisturbed glacially overridden soil should be designed for an allowable bearing pressure of up to 10,000 pounds per square foot (psf). Where densely compacted structural fill is placed over native, dense glacially overridden soil, an allowable bearing pressure

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of 4,000 psf should be used. Bearing pressures can be increased by up to one-third for seismic and wind loads (U.S. Navy, 1982).

Minimum footing widths should be 24 inches for individual column footings and 18 inches for continuous spread footings. Exterior footings should be at least 1.5 feet below the lowest adjacent grade.

We recommend that all footing subgrades exposed during construction be evaluated by a Shannon & Wilson, Inc. representative. This would allow us to confirm the subgrade conditions and to make recommendations where unanticipated conditions exist. Native footing subgrade soils disturbed during footing excavation should be compacted prior to placement of steel and concrete forms.

7.3 Estimated Settlements

We estimate settlements to be less than ½ inch, with differential settlements (between adjacent footings or over a 20-foot-long span of continuous footing) less than ¼ inch, provided footings are designed and constructed in accordance with our recommendations. These settlements are expected to occur essentially as the building is constructed and structural loads are applied.

7.4 Seismic Design

7.4.1 Design Ground Motions

We understand that seismic design for the project will be performed in accordance with the 2012 International Building Code (IBC) (International Code Council, Inc., 2012) and American Society of Civil Engineers 7-10. Seismic design considers the “maximum considered earthquake,” which corresponds to ground motions with 2 percent probability of exceedance in 50 years or about a 2,475-year return period.

Seismic design using the IBC 2012 utilize mapped short-period and 1-second period spectral accelerations, Ss and S1, respectively. We estimated the ground motion parameters using the U.S. Geological Survey (USGS) Seismic Hazard Curves and Uniform Hazard Response Spectrum application (USGS, 2008). Based on the observed subsurface conditions, in our opinion, the 308 and 310 9th Avenue N site corresponds to a Site Class C. The seismic design ground motion parameters are tabulated in the Table 1.

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TABLE 1 INTERNATIONAL BUILDING CODE 2012

SEISMIC DESIGN GROUND MOTION PARAMETERS

Spectral Response Acceleration (SRA) and Site Coefficients

Short Period 1 Second Period

Mapped SRA Ss = 1.344g S1 = 0.521g

Site Coefficients Fa = 1.0 Fv = 1.3

Maximum Considered Earthquake SRA SMS = 1.344g SM1 = 0.677g

Design SRA SDS = 0.896g SD1 = 0.451g

7.4.2 Earthquake-induced Geologic Hazards

Earthquake-induced geologic hazards may include liquefaction, lateral spreading, slope instability, and ground surface fault rupture. In our opinion, the potential for liquefaction and lateral spreading is insignificant because of the composition and density of the on-site soils. Based on the site conditions and location the potential for earthquake-induced ground surface fault rupture and slope instability is also insignificant.

7.5 Lateral Earth Pressures

Lateral earth pressures act on the buried portions of building walls. For walls allowed to move at least 0.001 times the wall height, we recommend using a static, active lateral earth pressure equivalent to a fluid weight of 37 pounds per cubic footing (pcf) for design. For buried walls that are not allowed to deflect 0.001 times the wall height (braced condition), a static, at-rest lateral earth pressure based on an equivalent fluid density of 58 pcf should be used. If a slope is present above the top of a retaining wall, Figure 3 can be used to estimate additional lateral pressures. These lateral earth pressures are based on the assumption that the wall backfill includes proper drainage so hydrostatic pressures will not build up.

Total earth pressure should be analyzed for seismic loading conditions using a uniformly distributed pressure increase of 13 psf per foot of wall height. The load increase for seismic conditions is consistent with a pseudo-static analysis using the Mononobe-Okabe equation for lateral earth pressures and a horizontal seismic coefficient of 0.28. This horizontal seismic coefficient is consistent with ground motion criteria in the 2012 IBC and is approximately one-half the peak ground acceleration. These pressures are based on the assumption of very dense soil and drained conditions behind the wall, and a horizontal backfill surface.

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7.6 Lateral Resistance

Lateral forces would be resisted by passive earth pressure against the buried portions of the structures and friction against the bottom. In our opinion, passive earth pressures developed from compacted granular fill could be estimated using an equivalent fluid unit weight of 250 pcf. This value is based on the assumption that the structure extends at least 1.5 feet below the lowest adjacent exterior grade, is properly drained, and that the backfill around the structure is compacted in accordance with the recommendations for structural fill presented in Section 8.1. If footings are cast directly against glacially overridden (dense) soil, passive earth pressure could be increased to 400 pcf. The above equivalent fluid unit weight includes a factor of safety of 1.5 to limit lateral deflection.

7.7 Base Footing Friction

We recommend a coefficient of friction of 0.50 be used between cast-in-place concrete and undisturbed, dense, glacially overridden soil. A coefficient of friction of 0.35 should be used for footings bearing on compacted structural fill. These values include a factor of safety of 1.5.

7.8 Floor Slabs

We recommend that floor slabs be supported on dense glacial soils or compacted structural fill placed directly onto dense, native subgrades. If loose, soft, or otherwise unsuitable soil is encountered, it should be removed and replaced with compacted structural fill. Structural fill should be compacted to a dense, unyielding condition. A modulus of subgrade reaction of 300 pounds per cubic inch may be used to design the slab, assuming dense structural fill or dense native subgrades are present.

We recommend placing a capillary break consisting of a minimum 6-inch-thick layer of ⅝-inch, clean crushed rock or washed pea gravel (⅜ to No. 8 sieve size), and an overlying vapor retarded consisting of 10 mil (minimum) plastic sheeting.

7.9 Drainage

A geocomposite mat should be installed between the temporary shoring wall and the permanent wall. Wall drainage behind temporary shoring walls should connect into a tightline. Typical wall and subdrainage and backfilling recommendations are presented in Figure 4.

Precipitation water from roof downspouts should be collected into tight lines and routed away from the building using tightline pipes. Downspout water should not be introduced into the

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ground. Provisions should be made to divert surface water away from structures and prevent it from seeping into the ground adjacent to structures or excavations. Surface water should be collected in catch basins and, along with downspout water, should be conveyed in a nonperforated pipe (tightline) to an approved discharge point.

7.10 Temporary Soil Nail Shoring

We recommend using a temporary soil nail shoring wall to facilitate excavation of the site. Soil nailing consists of drilling and grouting a series of steel bars or “nails” behind the excavation face and the covering the face with temporary or permanent reinforced shotcrete. The placement of relatively closely spaced steel nails in the retained soil mass increases the shear resistance of the soil against rotational sliding, increases the tensile strength of the soil behind potential slip surfaces, and moderately increases shear resistance at a potential slip surface due to the bending stiffness of the nails.

Soil nailing is most effective in dense, granular soils and stiff, low plasticity, fine-grained soil. It is generally not used in loose granular soils, soft cohesive soils, highly plastic clays, or where uncontrolled groundwater exists above the bottom of the excavation. In general, excavation faces with heights of 7 to 9 feet must be able to stand unsupported for 24 hours in order for soil nailing to be cost effective unless vertical steel elements are installed to provide additional support of the soil face.

Shored excavations will be required along all sides of the site. Proposed excavation depths are about 40 feet across the site. Soils to be retained mostly consist of dense to very dense silty sand with gravel. These soils are suitable for temporary and/or permanent soil nail walls. Use of soil nail showing will require temporary easements from the city and adjacent property owners. Local groundwater may be encountered during excavations. The poorly graded sand lens encountered during drilling at approximately 24 feet bgs has the possibility to cave during construction. Therefore, it may be necessary to used smaller lift heights while excavating this material.

Construction of soil nail walls involves a top-down procedure that generally includes three steps for each horizontal row of nails: (a) staged excavation, (b) nail installation and select nail testing, and (c) drainage and facing construction. This sequence of staged excavation, nail installation, and drainage/facing construction in horizontal rows is repeated until the excavation and shoring is complete. Soil nails consist of steel bars (typically ¾- to 1⅜-inch-diameter), which are installed by tremie-grouting the nail into a predrilled hole. Soil nails are located in

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square or rectangular grid patterns and are typically installed at an inclination angle of 15 degrees below horizontal. Drainage should be provided behind these walls by placing vertical rows of geosynthetic drainage composites between the grids of soil nails and connecting these to collection tightline pipes at the bottom of the wall. Facing typically consists of shotcrete sprayed over a steel mesh (temporary walls) or reinforcing steel bars (permanent walls) on the face of the cut excavation that connects to the soil nails and bearing plates.

In general, the first row of nails is installed not more than 2 to 4 feet bgs, and the bottom row of nails is installed less than 4 feet above the bottom of the cut or excavation. Soil nail lengths typically range from 0.7 to 1.0 times the wall height. For very dense glacially overridden soil that is present at this site, the soil nail lengths likely would be about 0.7 times the wall height.

We understand the design of the soil nail wall system will be provided by the shoring contractor. We recommend using the following design parameters for soil nail shoring design:

RECOMMENDED SOIL NAIL WALL DESIGN PARAMETERS

Soil Unit Friction Angle

(degrees) Cohesion

(psf) Unit Weight

(pcf) Ultimate Pullout

Friction (kips/foot)

Glacially Overridden Deposits 35 0 135 8.0

Notes: It is assumed that the first row of nails will be installed into glacially overridden deposits Ultimate Pullout Friction assumes 6-inch-diameter tremie-grouted soil nails psf = pounds per square foot pcf = pounds per cubic foot Federal Highway Administration (FHWA), 2015.

Foundation underpinning may be required for the brick building located to the north of the project site at 312 9th Avenue N. Underpinning will assist in controlling the settlement of the structure during construction. We recommend that the adjacent building be underpinned prior to excavation below the foundation elevation.

8.0 CONSTRUCTION CONSIDERATIONS

8.1 Fill Placement, Use of On-site Soils, and Compaction

In areas to be filled, such as beneath foundations, floor slabs, and pavements, the exposed soil surface, after clearing and prior to any fill placement, should be compacted using a heavy vibratory roller or backhoe-mounted hydraulic plate compactor. It should also be evaluated by an experienced geotechnical engineer probing with a steel T-bar. Where unsuitable soil that is

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loose, soft, wet, or contains organic material is encountered during the compaction process, it should be removed and replaced with densely compacted structural fill.

Native granular soil in dry conditions and granular on-site fill material without debris, wood, and free of topsoil (abundant organic material) would be suitable for use as structural fill provided the soil is within +/- 2 percent of its optimum moisture content for compaction. On-site fill soil could be re-used as structural fill provided it is evaluated by a geotechnical engineer and used following the recommendations in Section 7.2.

Imported structural fill soil should consist of a well-graded mixture of sand and gravel; free of organics, debris, and rubbish; and should contain no more than 20 percent fines (material passing the No. 200 mesh sieve, based on the minus ¾-inch fraction). The fines should be nonplastic, and the moisture content of the soil should also be within +/- 2 percent of its optimum. All structural fill should have a maximum particle size of 3 inches.

Structural fill should be placed in uniform lifts and compacted to a dense and unyielding condition, to at least 95 percent of the Modified Proctor maximum dry density (ASTM D1557-70). The thickness of soil layers before compaction should not exceed 8 inches for heavy equipment compactors or 4 inches for hand-operated mechanical compactors. In landscaped areas, where larger settlements are acceptable, the backfill should be compacted to at least 90 percent of the Modified Proctor maximum dry density.

During wet weather or in wet conditions where control of soil moisture is difficult, structural fill material should consist of clean, granular soil, of which not more than 5 percent by dry weight passes the No. 200 mesh sieve, based on wet-sieving the fraction passing the ¾-inch sieve. The fines should be nonplastic.

8.2 Excavation Monitoring

We recommend that an optical survey program be implemented to monitor movements during excavation and shoring installation. A preconstruction crack survey of adjacent streets, buildings, and facilities should be completed prior to any excavation or shoring, and monitoring baseline readings should be established before excavation begins. We recommend that optical survey points be established on existing structures located within a distance equal to 1.5 times the depth of the excavation from the top of the excavation.

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We recommend that optical survey points be established at 20-foot spacing on the shoring wall as excavation progresses. Monitoring points should be evaluated on a weekly basis during construction or as excavation progress dictates. If horizontal movements are observed to be in excess of 1- or ½-inch between successive readings, construction of the soil nail wall should be stopped to determine the cause of the movement and to establish the type and extent of mitigation measures. The survey points should be monitored until lateral loads are fully supported by the permanent structure. The top row of soil nails should be recorded for vertical and horizontal movement, and survey points 20 feet behind the soil nail wall should also be installed in the streets and monitored similarly, as recommended above.

8.3 Temporary Excavation Slopes

Temporary excavation slopes should be made the responsibility of the Contractor who is continually at the site; is able to observe the nature and conditions of the subsurface materials encountered, including groundwater; and has responsibility for the methods, sequence, and schedule of construction.

For planning purposes, we recommend that temporary, unsupported, open-cut slopes be no steeper than 1 Horizontal to 1 Vertical (1H:1V) in glacially overridden soil. For slopes cut in fill or loose surficial soils, we recommend they be made no steeper than 1.5H:1V. These recommendations are applicable to slopes in areas where groundwater and/or groundwater seepage is not present. Flatter slopes may be required based on the actual conditions encountered, particularly where groundwater or seepage is encountered. We recommend that all exposed slopes be protected with waterproof covering during periods of wet weather to reduce sloughing and erosion.

8.4 Temporary Groundwater Control

We anticipate that temporary groundwater control may be required during construction. We expect that trenching and sumps will be adequate for construction dewatering.

8.5 Wet Weather Earthwork

Wet weather generally begins about mid-October and continues through about May, although rainy periods may occur at any time of year. Some of the soil at the site contains sufficient silts and fines to produce an unstable mixture when wet. Such soils are susceptible to changes in water content, and they tend to become unstable and difficult, or impossible, to compact if their

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moisture content significantly exceeds the optimum. If earthwork at the site continues into the wet season, or if wet conditions are encountered, we recommend the following:

The ground surface in and surrounding the construction area should be sloped as much as possible to promote runoff of precipitation away from work areas and to prevent ponding of water.

Earthwork should be accomplished in small sections to minimize exposure to wet conditions. That is, each section should be small enough so that the removal of unsuitable soils and placement and compaction of clean structural fill can be accomplished on the same day. The size of construction equipment may have to be limited to prevent soil disturbance. It may be necessary to excavate soils with a backhoe, or equivalent, located so that equipment does not traffic over the excavated area. Thus, subgrade disturbance caused by equipment traffic will be minimized.

Fill material should consist of clean, well-graded, pit-run sand and gravel soils of which not more than 5 percent fines by dry weight passes the No. 200 mesh sieve, based on wet-sieving the fraction passing the ¾-inch mesh sieve. The gravel content should range between 20 and 60 percent retained on a No. 4 mesh sieve. The fines should be nonplastic.

No soil should be left uncompacted and exposed to moisture. A smooth-drum vibratory roller, or equivalent, should roll the surface to seal out as much water as possible.

In-place soils or fill soils that become wet and unstable and/or too wet to suitably compact should be removed and replaced with clean, granular soil (see third bullet).

Excavation and placement of structural fill material should be observed on a full-time basis by a geotechnical engineer (or representative) experienced in earthwork to determine that all work is being accomplished in accordance with the project specifications and our recommendations.

Grading and earthwork should not be accomplished during periods of heavy, continuous rainfall.

We suggest that these recommendations for wet weather earthwork be included in the contract specifications.

8.6 Erosion Control

The Contractor should employ proper erosion control measures during construction, especially if construction takes place during wet weather. Covering work areas, soil stockpiles, or slopes with plastic and using sandbags, sumps, and other measures should be employed as necessary to permit proper completion of the work. Bales of straw, geotextile silt fences, rock-stabilized

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entrance, and wheel wash (as appropriate, street sweeper, and drain inlet sediment screens/collection systems should be appropriately located to control soil movement and erosion.

8.7 Obstructions

Buildings components previously and currently on site, such as floor slabs, footings, and basement walls, could be partially or completely buried. The existing foundations, walls, and slabs should be anticipated and could require special demolition consideration during shoring installation and site excavation.

Although boulders were not encountered in the explorations, it has been our experience that cobbles and boulders are commonly encountered in glacial soils. We recommend that contract documents contain an advisory statement that cobbles, boulders, and other obstructions could be encountered in the mass excavation and soil nail drill holes. The presence of these materials could require installing additional nails or altering construction procedures. The Contractor should be prepared to remove any cobbles, boulders, or other obstructions that protrude into the soil face of the excavation. The void produced by removing face obstructions should be backfilled with shotcrete.

9.0 ADDITIONAL SERVICES

We recommend that Shannon & Wilson, Inc. be retained to review the geotechnical aspects of plans and specifications to determine that they are consistent with our recommendations. In addition, we should be retained to observe the geotechnical aspects of construction, particularly foundations, shoring, and backfill. Observation will allow us to evaluate the subsurface conditions as they are exposed during construction and to determine that the work is accomplished in accordance with our recommendations and the project specifications.

10.0 LIMITATIONS

The analyses, conclusions, and recommendations contained in this report are based on site conditions as they presently exist, and further assume that the explorations are representative of the subsurface conditions throughout the site; that is, the subsurface conditions everywhere are not significantly different from those disclosed by the explorations. If subsurface conditions different from those encountered in the explorations are encountered or appear to be present during construction, we should be advised at once so that we can review these conditions and reconsider our recommendations, where necessary. If there is a substantial lapse of time between the submission of this report and the start of construction at the site, or if conditions have

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changed because of natural forces or construction operations at or adjacent to the site, we recommend that we review our report to determine the applicability of the conclusions and recommendations.

Within the limitations of scope, schedule, and budget, the analyses, conclusions, and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical engineering principles and practice in this area at the time this report was prepared. We make no other warranty, either express or implied. These conclusions and recommendations were based on our understanding of the project as described in this report and the site conditions as observed at the time of our explorations.

Unanticipated soil conditions are commonly encountered and cannot be fully determined by merely taking soil samples from test borings. Such unexpected conditions frequently require that additional expenditures be made to attain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs.

This report was prepared for the exclusive use of Equinox Properties Corp. and their design team in the design of the 308 and 310 9th Avenue N project. The data and report should be provided to the contractors for factual information, but our report, conclusions, and interpretations should not be construed as a warranty of subsurface conditions included in this report.

The scope of our present work included a limited environmental assessment (geoprobes) regarding the presence or absence of hazardous or toxic substances in the soil on this site. No contaminates were observed in our two geoprobes, however; this should not be construed as evidence that the property is free of contaminated soils because our explorations were limited and did not cover all portions of the property. Our geoprobe explorations were not intended to serve as a Phase II Environmental Site Assessment.

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11.0 REFERENCES

ASTM International (ASTM), 2012, Annual book of standards, Construction, v. 04.08, Soil and Rock (I): D420 – D5779: West Conshohocken, Pa.

Federal Highway Administration (FHWA), 2015, Publication No. FHWA-NHI-14-007, GEC No. 7.

GeoEngineers, Inc., 2001, Geotechnical Engineering Services Report, Proposed All Phase Building Redevelopment, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

GeoEngineers, Inc., 2002, Geotechnical Engineering Services Report, SBRI Building Project, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

GeoEngineers, Inc., 2015, Geotechnical Master Use Permit Report, 901 Harrison Street Development, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

International Code Council, Inc., 2012, International building code: Country Club Hills, Ill., International Code Council, Inc., 690 p.

Shannon & Wilson, Inc., 2014, Geotechnical Report, 9th and Thomas Development, Seattle, Washington: Report prepared by Shannon & Wilson, Inc., Seattle, Washington.

Thorson, R.M., 1989, Glacio-isostatic response of the Puget Sound area, Washington; Geological Society of American Bulletin, v. 101, no. 9, p. 1163-1174.

U.S. Geological Survey (USGS), 2008, 2008 interactive deaggregations (beta): Available: https://geohazards.usgs.gov/deaggint/2008/.

U.S. Navy, 1982, Soil Mechanics, Design Manual 7.1, NAVFAC DM-7.1/7.2.

VICINITY MAP

FIG. 1

PROJECT

LOCATION

308 and 310 9th Avenue North

Seattle, Washington

Map adapted from aerial imagery provided by

Google Earth Pro, reproduced by permission

granted by Google Earth ™ Mapping Service.

NOTE

March 2016 21-1-22203-001

File

na

me

: J:\2

11

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03

-0

01

\2

1-1

-2

22

03

-0

01

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ig

1

.d

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D

ate

: 0

3-1

0-2

01

6 L

og

in

: sa

c

Seattle

Washington

Project

Location

90

5

97

0 500 1000

Approximate Scale in Feet

5

MT

FIG. 2

SITE AND EXPLORATION PLAN

Filenam

e: J:\211\22203-001\21-1-22203-001 F

ig 2.dw

g Layout: S

ite P

lan

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ate: 03-10-2016 Login: sac


Seattle, Washington

March 2016 21-1-22203-001

SW-1

Proposed Excavation

Project Boring Designation and

Approximate Location

Project GeoProbe Designation

and Approximate Location

Boring Designation and


(GeoEngineers, March 2001)



(GeoEngineers, June 2002)



(GeoEngineers, February 2015)



(Shannon & Wilson, 2014)

LEGEND

NOTE

0 50 100

Approximate Scale in Feet

Map adapted from aerial imagery provided by

Google Earth Pro, reproduced by permission

granted by Google Earth ™ Mapping Service.

MT

GP-1

B-1

B-5

B46-1

SW-2

For m ≤ 0.4: H

= 0.28 (psf) (see Note 3)

RECOMMENDED SURCHARGE

LOADING FOR TEMPORARY AND

PERMANENT WALLS

FIG. 3

File: J:\211\22203-001\21-1-22203-001 F

ig 3.dw

g D

ate: 03-10-2016 A

uthor: sac

Wall

PLAN VIEW

2.0

1.5

Depth F

actor, Z

/B

1.0

0.0

0.5

Wall

Z

Wall Line

UNIFORM SURCHARGE

EARTH BERM

(see Note 4)

Note:

H

z=nH

Bottom of

Excavation

x = mH

Point Load

in Pounds

H

(psf)

ELEVATION VIEW

x = mH

H

Bottom of

Excavation

Wall

z=nH

H

(psf)

Line Load in

Pounds/Foot

B) LATERAL PRESSURE DUE TO LINE LOAD

i.e. NARROW CONTINUOUS FOOTING

PARALLEL TO WALL

C) LATERAL PRESSURE DUE TO STRIP LOAD

Wall

Wall

Wall

A) LATERAL PRESSURE DUE TO POINT LOAD

i.e. SMALL ISOLATED FOOTING OR WHEEL LOAD

D) LATERAL PRESSURE DUE TO EARTH BERM

OR UNIFORM SURCHARGE

Bottom of

Excavation

Bottom of

Excavation

E) LATERAL PRESSURE DUE

TO ADJACENT FOOTING

(see Notes 5 and 6)

0 0.5 1.0

L

2

B

NOTES

Figures are not drawn to scale.

Applicable surcharge pressures should be

added to appropriate permanent wall lateral

earth and water pressure.

If point or line loads are close to the back of

the wall such that m 0.4, it may be more

appropriate to model the actual load

distribution (i.e., Detail E) or use more rigorous

analysis methods.

Active earth pressure coefficient, K = 0.22.

The stress is estimated on the back of the wall

at the center of the length, L, of loading.

The estimated stress is based on a Poisson's

ratio of 0.5.

Wall

Bearing

Pressure

q (psf)

1.

2.

3.

4.

5.

6.

=

I

p

, Influence Factor

H

= 2(I

p

) q

s

Lateral Footing

Pressure on Wall

(derived from NAVFAC DM 7.02,

1986; and Sandhu, Earth Pressure

on Walls Due to Surcharge, 1974)

(derived from Poulos and Davis, Elastic Solutions for

Soil and Rock Mechanics, 1974; and Terzaghi and

Peck, Soil Mechanics in Engineering Practice, 1967)

(NAVFAC DM 7.02, 1986)

(derived from Fang, Foundation

Engineering Handbook, 1991)

(NAVFAC DM 7.2, 1986)

Point Load

in Pounds

= Unit Weight

of Earth Berm

Bearing

Pressure

Earth

Berm

H

= Lateral Pressure

in radians

ELEVATION VIEW

(see Note 3)

(see Note 3)

q

s

L

2B

Q

p

H

2

n

2

(0.16 + n

2

)

3

For m > 0.4: H

= 1.77 (psf)

Q

p

H

2

m

2

n

2

(m

2

+ n

2

)

3

Q

p

H

'

H

= H

cos

2

(1.1) (psf)

'

H

'

H

For m ≤ 0.4: H

= 0.20 (psf) (see Note 3)

Q

l

H

n

(0.16 + n

2

)

2

For m > 0.4: H

= 1.28 (psf)

Q

l

H

m

2

n

(m

2

+ n

2

)

2

Q

l

Q

p

≤ 33°

H

s

≤ 15 Feet

(K)()(Hs

)

2

H

H

s

H

= (K)q

s

(see Note 4)

q

s

(psf)

H

= ( - sin cos2) (psf)

2q

L

2

= 0.25

= 0.5

= 1

H

= ∞

L

2B

L

2B

L

2B


Seattle, Washington

March 2016 21-1-22203-001

TYPICAL WALL DRAINAGE

FIG. 4

Wall drainage material: Geodrain, Miradrain 6000

or equivalent drainage composite.

NOTE

Not to Scale

Section A-A'

Floor Slab

Formed Concrete or Shotcrete Wall

Cast Against Waterproof Layer

Prefabricated Drain Grate and Tightline

Through Permanent Wall Connected to

Geocomposite Drainage Board

Drainage Gravel

(Pea Gravel)

4-in. Tightline Connected

to Storm Drain

AA'

Vapor Barrier

Wall Footing

Waterproof Membrane

12-in. Min.

PLAN VIEW

File

na

me

: J:\2

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\2

22

03

-0

01

\2

1-1

-2

22

03

-0

01

F

ig

4

.d

wg

L

ayo

ut: L

ayo

ut1

D

ate

: 0

3-1

0-2

01

6 L

og

in

: sa

c

Temporary Shotcrete

Geocomposite Drainage Board


Seattle, Washington

March 2016 21-1-22203-001

21-1-22203-001

APPENDIX A

SUBSURFACE EXPLORATIONS

21-1-22203-001-R1-AA/wp/lkn 21-1-22203-001 A-i

APPENDIX A

SUBSURFACE EXPLORATIONS

TABLE OF CONTENTS

Page

A.1 GENERAL ...................................................................................................................... A-1

A.2 SOIL BORINGS ............................................................................................................. A-1

A.3 GEOPROBE EXPLORATIONS .................................................................................... A-1

A.4 GROUNDWATER OBSERVATIONS .......................................................................... A-2

A.5 SOIL SAMPLING AND CLASSIFICATION ............................................................... A-2

A.6 FIELD SCREENING METHODS ................................................................................. A-2

A.7 EXISTING EXPLORATIONS ....................................................................................... A-2

A.8 REFERENCES ............................................................................................................... A-3

FIGURES

A-1 Soil Description and Log Key (3 sheets) A-2 Log of Boring SW-1 A-3 Log of Geoprobe GP-1 A-4 Log of Geoprobe GP-2 A-5 GeoEngineers (2001) Log of Boring B-1 (2 sheets) A-6 GeoEngineers (2001) Log of Boring B-2 (2 sheets) A-7 GeoEngineers (2001) Log of Boring B-3 (2 sheets) A-8 GeoEngineers (2001) Log of Boring B-4 (2 sheets) A-9 GeoEngineers (2002) Log of Boring B-5 A-10 Shannon & Wilson, Inc. (214) Log of Boring SW-2 A-11 GeoEngineers (2015) Log of Boring B46-1 (2 sheets)

21-1-22203-001-R1-AA/wp/lkn 21-1-22203-001 A-1

APPENDIX A

SUBSURFACE EXPLORATIONS A.1 GENERAL

The subsurface exploration program for the project was conducted by Shannon & Wilson, Inc. The exploration program consisted of one soil boring, designated SW-1 and two geoprobes, designated GP-1 and GP-2. The approximate locations of the explorations are shown in Figure 2 and should be considered approximate.

The logs of the soil borings are presented as Figures A-2 to A-4. Figure A-1 presents a key to our classification of the soils encountered in the explorations.

A.2 SOIL BORINGS

The soil borings were drilled by Gregory Drilling, Inc. The boring was completed on February 29, 2016, and extended 41.5 feet below existing grade. Disturbed samples were obtained in conjunction with the Standard Penetration Test (SPT). The SPT test is an in situ soil test, which can be used to interpret the several engineering properties of soils (see Section A.4). The Unified Soil Classification System (USCS), as described in Figure A-1, was used to classify the soils.

Gregory Drilling, Inc. completed the soil borings using a track-mounted drill rig using hollow-stem auger (HSA) drilling techniques. HSA drilling consists of advancing continuous-flight augers to remove soil from the borehole. Soil samples are taken from the bottom of the boring by removing the center rod and lowering a split-spoon sampler through the hollow stem. Soil samples were taken in 5-foot intervals. A monitoring well was installed in boring SW-1, shown in Figure A-2. Drill cuttings and spoils were placed in drums for disposal offsite.

A.3 GEOPROBE EXPLORATIONS

The geoprobes were advanced by ESN Northwest, Inc. (ESN) on February 29, 2016. ESN used a limited access direct push hydraulic geoprobe rig do advance a continuous sample tube into the ground until refusal was met at 5.5 to 6 feet. Samples were visually classified using the USCS, as described in Figure A-1.

21-1-22203-001-R1-AA/wp/lkn 21-1-22203-001 A-2

A.4 GROUNDWATER OBSERVATIONS

Groundwater was not observed during drilling. However, a Shannon & Wilson, Inc. representative read the monitoring well on March 10, 2016, and did not observe ground water in the well.

A.5 SOIL SAMPLING AND CLASSIFICATION

A Shannon & Wilson, Inc. geotechnical staff observed and logged the drilling operations. Representative soil samples collected were transferred to our laboratory in Seattle, Washington, for analysis. The field logs and soil samples were reviewed by Shannon & Wilson, Inc. personnel in the Seattle laboratory using the USCS field classification method. The boring logs in this report represent our interpretation of the field logs.

Disturbed soil samples were obtained in conjunction with the SPT. SPTs were performed in general accordance with the ASTM International (ASTM) Designation: D1586, Test Method for Penetration Test and Split-Barrel Sampling of Soils (ASTM, 2010). SPTs were collected in the borings at 5-foot intervals. The SPT consists of driving a 2-inch outside diameter split-spoon sampler a total distance of 18 inches below the bottom of the drill hole with a 140-pound hammer falling 30 inches. The number of blows required to advance the split spoon from 6 to 18 inches of penetration is termed the Standard Penetration Resistance (N-value). The N-values are plotted in the boring logs presented in this appendix. These values provide a means for evaluating the relative density of granular soils and the relative consistency (stiffness) of cohesive soils.

A.6 FIELD SCREENING METHODS

Field screening of geoprobe and boring samples for potential contamination was conducted. Field screening methods consisted of:

Photoionization detector (PID) Olfactory observations

A.7 EXISTING EXPLORATIONS

We reviewed seven subsurface exploration logs previously completed by other geotechnical consultants for other projects adjacent to the subject property. These consisted of logs from:

21-1-22203-001-R1-AA/wp/lkn 21-1-22203-001 A-3

B46-1 (GeoEngineers, Inc., 2015) SW-2 (Shannon & Wilson, Inc., 2014) B-5 (GeoEngineers, Inc., 2002) B-1 – B-4 (GeoEngineers, Inc., 2001)

Descriptions of the drilling methods and sampling procedures can be found in the respective report. The approximate locations of the existing borings are shown in Figure 2. The boring logs are included as Figures A-5 to A-11.

A.8 REFERENCES

ASTM International (ASTM), 2010, 2010 Annual book of standards, Construction, v. 04.08, Soil and rock (I): D420 - D5876: West Conshohocken, Pa.

GeoEngineers, Inc., 2001, Geotechnical Engineering Services Report, Proposed All Phase Building Redevelopment, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

GeoEngineers, Inc., 2002, Geotechnical Engineering Services Report, SBRI Building Project, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

GeoEngineers, Inc., 2015, Geotechnical Master Use Permit Report, 901 Harrison Street Development, Seattle, Washington: Report prepared by GeoEngineers, Inc., Redmond, Washington.

Shannon & Wilson, Inc., 2014, Geotechnical Report, 9th and Thomas Development, Seattle, Washington: Report prepared by Shannon & Wilson, Inc., Seattle, Washington.

March 2016 21-1-22203-001

308 and 310 9th Avenue NSeattle, Washington

1Gravel, sand, and fines estimated by mass. Other constituents, such asorganics, cobbles, and boulders, estimated by volume.

2Reprinted, with permission, from ASTM D2488 - 09a Standard Practice forDescription and Identification of Soils (Visual-Manual Procedure), copyrightASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.A copy of the complete standard may be obtained from ASTM International,www.astm.org.

140 pounds with a 30-inch free fall.Rope on 6- to 10-inch-diam. cathead2-1/4 rope turns, > 100 rpm

NOTE: If automatic hammers areused, blow counts shown on boringlogs should be adjusted to account forefficiency of hammer.

10 to 30 inches longShoe I.D. = 1.375 inchesBarrel I.D. = 1.5 inchesBarrel O.D. = 2 inches

Sum blow counts for second and third6-inch increments.Refusal: 50 blows for 6 inches orless; 10 blows for 0 inches.

RELATIVECONSISTENCY

N, SPT,BLOWS/FT.

5% to 12%fine-grained:with Silt orwith Clay 3

15% or more of asecond coarse-

grained constituent:with Sand orwith Gravel 5

< 5%

5 to 10%

15 to 25%

30 to 45%

50 to 100%

Surface CementSeal

Asphalt or Cap

Slough

Inclinometer orNon-perforated Casing

Vibrating WirePiezometer

N, SPT,BLOWS/FT.

< 44 - 10

10 - 3030 - 50

> 50

DESCRIPTION

< #200 (0.075 mm = 0.003 in.)

#200 to #40 (0.075 to 0.4 mm; 0.003 to 0.02 in.)#40 to #10 (0.4 to 2 mm; 0.02 to 0.08 in.)#10 to #4 (2 to 4.75 mm; 0.08 to 0.187 in.)

SIEVE NUMBER AND/OR APPROXIMATE SIZE

#4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.)3/4 to 3 in. (19 to 76 mm)

3 to 12 in. (76 to 305 mm)

> 12 in. (305 mm)

FineCoarse

FineMediumCoarse

BOULDERS

COBBLES

GRAVEL

FINES

SAND

Sheet 1 of 3

CONSTITUENT2

SOIL DESCRIPTIONAND LOG KEY

SHANNON & WILSON, INC.Geotechnical and Environmental Consultants

Absence of moisture, dusty, dryto the touch

Damp but no visible water

Visible free water, from belowwater table

FIG. A-1

Shannon & Wilson, Inc. (S&W), uses a soilidentification system modified from the UnifiedSoil Classification System (USCS). Elements ofthe USCS and other definitions are provided onthis and the following pages. Soil descriptionsare based on visual-manual procedures (ASTMD2488) and laboratory testing procedures(ASTM D2487), if performed.

STANDARD PENETRATION TEST (SPT)SPECIFICATIONS

Hammer:

Sampler:

N-Value:

Dry

Moist

Wet

MOISTURE CONTENT TERMS

Modifying(Secondary)

Precedes majorconstituent

Major

MinorFollows major

constituent

1All percentages are by weight of total specimen passing a 3-inch sieve.2The order of terms is: Modifying Major with Minor.3Determined based on behavior.4Determined based on which constituent comprises a larger percentage.5Whichever is the lesser constituent.

COARSE-GRAINEDSOILS

(less than 50% fines)1

NOTE: Penetration resistances (N-values) shown on boring logs are as recorded in the field and have not been corrected for hammer efficiency, overburden, or other factors.

PARTICLE SIZE DEFINITIONS

RELATIVE DENSITY / CONSISTENCYSand or Gravel 4

30% or morecoarse-grained:

Sandy or Gravelly 4

More than 12%fine-grained:

Silty or Clayey 3

15% to 30%coarse-grained:with Sand orwith Gravel 4

30% or more totalcoarse-grained and

lesser coarse-grained constituent

is 15% or more:with Sand orwith Gravel 5

Very softSoftMedium stiffStiffVery stiffHard

Very looseLooseMedium denseDenseVery dense

RELATIVEDENSITY

FINE-GRAINED SOILS(50% or more fines)1

COHESIVE SOILS

< 22 - 44 - 8

8 - 1515 - 30

> 30

COHESIONLESS SOILS

Silt, Lean Clay,Elastic Silt, or

Fat Clay 3

PERCENTAGES TERMS 1, 2

Trace

Few

Little

Some

Mostly

WELL AND BACKFILL SYMBOLS

BentoniteCement Grout

Bentonite Grout

Bentonite Chips

Silica Sand

Perforated orScreened Casing

S&W INORGANIC SOIL CONSTITUENT DEFINITIONS

SO

IL_C

LAS

S_K

EY

_PG

1 2

1-22

203

.GP

J S

HA

N_W

IL.G

DT

3/1

5/1

6

March 2016 21-1-22203-001


GC

SC

Inorganic

Organic

(more than 50%of coarse

fraction retainedon No. 4 sieve)

MAJOR DIVISIONS GROUP/GRAPHICSYMBOL

CH

OH

ML

CL

TYPICAL IDENTIFICATIONS

Gravel

Sand

Silty Sand; Silty Sand with Gravel

Clayey Sand; Clayey Sand with Gravel

Clayey Gravel; Clayey Gravel withSand

Sheet 2 of 3

Gravels

Primarily organic matter, dark incolor, and organic odor

SW

(more than 12%fines)

Silts and Clays

Silts and Clays

(more than 50%retained on No.

200 sieve)

(50% or more ofcoarse fraction

passes the No. 4sieve)

(liquid limit lessthan 50)

(liquid limit 50 ormore)

Organic

Inorganic

FINE-GRAINEDSOILS

SM

Sands

Silty or ClayeyGravel

Silt; Silt with Sand or Gravel; Sandy orGravelly Silt

Organic Silt or Clay; Organic Silt orClay with Sand or Gravel; Sandy orGravelly Organic Silt or Clay

HIGHLY-ORGANIC

SOILS

COARSE-GRAINED

SOILS

OL

(less than 5%fines)

GW

Geotechnical and Environmental ConsultantsSHANNON & WILSON, INC.

(less than 5%fines)

PT

FIG. A-1

(more than 12%fines)

MH

SP

GP

GM

Silty orClayey Sand

Silty Gravel; Silty Gravel with Sand

(50% or morepasses the No.

200 sieve)


Elastic Silt; Elastic Silt with Sand orGravel; Sandy or Gravelly Elastic Silt

Fat Clay; Fat Clay with Sand or Gravel;Sandy or Gravelly Fat Clay

Organic Silt or Clay; Organic Silt orClay with Sand or Gravel; Sandy orGravelly Organic Silt or Clay

Poorly Graded Sand; Poorly GradedSand with Gravel

Well-Graded Sand; Well-Graded Sandwith Gravel

Well-Graded Gravel; Well-GradedGravel with Sand

Poorly Graded Gravel; Poorly GradedGravel with Sand

Lean Clay; Lean Clay with Sand orGravel; Sandy or Gravelly Lean Clay

NOTES

1. Dual symbols (symbols separated by a hyphen, i.e., SP-SM, Sandwith Silt) are used for soils with between 5% and 12% fines or whenthe liquid limit and plasticity index values plot in the CL-ML area ofthe plasticity chart. Graphics shown on the logs for these soil typesare a combination of the two graphic symbols (e.g., SP and SM).

2. Borderline symbols (symbols separated by a slash, i.e., CL/ML,Lean Clay to Silt; SP-SM/SM, Sand with Silt to Silty Sand) indicatethat the soil properties are close to the defining boundary betweentwo groups.

Peat or other highly organic soils (seeASTM D4427)

SO

IL_C

LAS

S_K

EY

_PG

2 2

1-22

203

.GP

J S

HA

N_W

IL.G

DT

3/1

5/1

6

NOTE: No. 4 size = 4.75 mm = 0.187 in.; No. 200 size = 0.075 mm = 0.003 in.

UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)(Modified From USACE Tech Memo 3-357, ASTM D2487, and ASTM D2488)

March 2016 21-1-22203-001


SHANNON & WILSON, INC.Geotechnical and Environmental Consultants

FIG. A-1Sheet 3 of 3


1Reprinted, with permission, from ASTM D2488 - 09a Standard Practice forDescription and Identification of Soils (Visual-Manual Procedure), copyright ASTMInternational, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy ofthe complete standard may be obtained from ASTM International, www.astm.org.

2Adapted, with permission, from ASTM D2488 - 09a Standard Practice forDescription and Identification of Soils (Visual-Manual Procedure), copyright ASTMInternational, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy ofthe complete standard may be obtained from ASTM International, www.astm.org.

Interbedded

Laminated

Fissured

Slickensided

Blocky

Lensed

Homogeneous

ATDDiam.Elev.

ft.FeOgal.

Horiz.HSAI.D.in.

lbs.MgOmm

MnONANP

O.D.OWpcf

PIDPMTppm

psiPVCrpmSPT

USCSqu

VWPVert.

WOHWOR

Wt.

Crumbles or breaks with handling or slightfinger pressure.Crumbles or breaks with considerable fingerpressure.Will not crumble or break with fingerpressure.

PLASTICITY2

CEMENTATION TERMS1

GRADATION TERMS

STRUCTURE TERMS1

ACRONYMS AND ABBREVIATIONS

Alternating layers of varying material orcolor with layers at least 1/4-inch thick;singular: bed.Alternating layers of varying material orcolor with layers less than 1/4-inch thick;singular: lamination.Breaks along definite planes or fractureswith little resistance.Fracture planes appear polished orglossy; sometimes striated.Cohesive soil that can be broken downinto small angular lumps that resist furtherbreakdown.Inclusion of small pockets of differentsoils, such as small lenses of sandscattered through a mass of clay.Same color and appearance throughout.

Narrow range of grain sizes present or, withinthe range of grain sizes present, one or moresizes are missing (Gap Graded). Meetscriteria in ASTM D2487, if tested.Full range and even distribution of grain sizespresent. Meets criteria in ASTM D2487, iftested.

Poorly Graded

Well-Graded

Weak

Moderate

Strong

Irregular patches of different colors.

Soil disturbance or mixing by plants oranimals.

Nonsorted sediment; sand and gravel in siltand/or clay matrix.

Material brought to surface by drilling.

Material that caved from sides of borehole.

Disturbed texture, mix of strengths.

VISUAL-MANUAL CRITERIA

A 1/8-in. thread cannot be rolledat any water content.A thread can barely be rolled anda lump cannot be formed whendrier than the plastic limit.A thread is easy to roll and notmuch time is required to reachthe plastic limit. The threadcannot be rerolled after reachingthe plastic limit. A lumpcrumbles when drier than theplastic limit.It takes considerable time rollingand kneading to reach the plasticlimit. A thread can be rerolledseveral times after reaching theplastic limit. A lump can beformed without crumbling whendrier than the plastic limit.

Sharp edges and unpolished planar surfaces.

Similar to angular, but with rounded edges.

Nearly planar sides with well-rounded edges.

Smoothly curved sides with no edges.

Width/thickness ratio > 3.

Length/width ratio > 3.

PARTICLE ANGULARITY AND SHAPE TERMS1

ADDITIONAL TERMS

Angular

Subangular

Subrounded

Rounded

Flat

Elongated

DESCRIPTION

Nonplastic

Low

Medium

High

At Time of DrillingDiameterElevationFeetIron OxideGallonsHorizontalHollow Stem AugerInside DiameterInchesPoundsMagnesium OxideMillimeterManganese OxideNot Applicable or Not AvailableNonplasticOutside DiameterObservation WellPounds per Cubic FootPhoto-Ionization DetectorPressuremeter TestParts per MillionPounds per Square InchPolyvinyl ChlorideRotations per MinuteStandard Penetration TestUnified Soil Classification SystemUnconfined Compressive StrengthVibrating Wire PiezometerVerticalWeight of HammerWeight of RodsWeight

Mottled

Bioturbated

Diamict

Cuttings

Slough

Sheared

APPROX.PLASITICITY

INDEXRANGE

< 4

4 to 10

10 to 20

> 20

SO

IL_C

LAS

S_K

EY

_PG

3 2

1-22

203

.GP

J S

HA

N_W

IL.G

DT

3/1

5/1

6

0.4

24.0

31.0

41.5

Non

e O

bser

ved

3/1

0/20

160.1

0.2

0

0

0

0

0

Concrete.

Dense to very dense, gray-brown, SiltySand with Gravel (SM); moist.(Glacial Till)

Very dense, light gray-brown, PoorlyGraded Sand (SP); moist; trace of finegravel.(Alluvium)

Very dense, gray-brown, Silty Sand withGravel (SM); moist.(Glacial Till)

BOTTOM OF BORINGCOMPLETED 3/1/2016

1

2

3

4

5

6

7

8

Dep

th, f

t.


Dep

th, f

t.

5

10

15

20

25

30

35

40

45

Well Screen and Sand Filter

Drilling Method:Drilling Company:Drill Rig Equipment:Other Comments:

Log:

BW

C

Northing:Easting:Station:Offset:

SOIL DESCRIPTION

20 40 60

Sam

ples

8 in.2.25 in.Safety

Refer to the report text for a proper understanding of thesubsurface materials and drilling methods. The

stratification lines represent the approximate boundariesbetween material types, and the transition may be gradual.

March 2016 21-1-22203-001

Typ

: LK

N

Geotechnical and Environmental Consultants

Sample Not Recovered

Bentonite-Cement Grout*

LOG OF BORING SW-1

0 60

0

PID

, pp

m

Total Depth:Top Elevation:Vert. Datum:Horiz. Datum:

2.0" O.D. Split Spoon Sample

Bentonite Chips/Pellets

Bentonite Grout

Hole Diam.:Rod Diam.:Hammer Type:

LEGEND

Sym

bol

1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions.

2. Groundwater level, if indicated above, is for the date specified and may vary.

3. USCS designation is based on visual-manual classification and selected lab testing.

Hollow Stem AugerGregory DrillingCME 55 LCX

FIG. A-2SHANNON & WILSON, INC.

41.5 ft.~ 58 ft.

Rev

: BW

C

REV 3 - Approved for Submittal

Scr

een

Des

ign

NOTES

20 40

MA

ST

ER

_LO

G_E

21-

222

03.G

PJ

SH

AN

_WIL

.GD

T 3

/14/

16

PENETRATION RESISTANCE Hammer Wt. & Drop:

(blows/foot)

140 lbs / 30 inches

% Fines (<0.075mm)

% Water Content

69

50/2"

50/5"

77

98/9"

65

66

0.3

6.0

Non

e O

bser

ved

Dur

ing

Dril

ling

0

0

Concrete.

Loose, light gray-brown, Silty Sand withGravel (SM); dry; brick pieces.(Fill)

BOTTOM OF GEOPROBECOMPLETED 2/29/2016

1

2

Dep

th, f

t.


Dep

th, f

t.

2

4

6

8

10

12

14

16

18


Log:

BW

C


SOIL DESCRIPTION

20 40 60

Sam

ples

2.25 in.



March 2016 21-1-22203-001

Typ

: LK

N


Sample Not Recovered*

LOG OF GEOPROBE GP-1

0 60

0

PID

, pp

m


2" Plastic Sheath with Soil Recovery


LEGEND

Sym

bol




Direct PushESN NorthwestPower Probe 9100P


5.5 ft.~ 58 ft.

Rev

: BW

C


Scr

een

Des

ign

NOTES

20 40

MA

ST

ER

_LO

G_E

21-

222

03.G

PJ

SH

AN

_WIL

.GD

T 3

/14/

16

% Fines (<0.075mm)

% Water Content

0.3

5.5

Non

e O

bser

ved

Dur

ing

Dril

ling

0

0

Concrete.

Medium dense, gray, Silty Sand (SM); dry;trace fine gravel.(Fill)

BOTTOM OF GEOPROBECOMPLETED 2/29/2016

1

2

Dep

th, f

t.


Dep

th, f

t.

2

4

6

8

10

12

14

16

18


Log:

BW

C


SOIL DESCRIPTION

20 40 60

Sam

ples

2.25 in.



March 2016 21-1-22203-001

Typ

: LK

N


Sample Not Recovered*

LOG OF GEOPROBE GP-2

0 60

0

PID

, pp

m


2" Plastic Sheath with Soil Recovery


LEGEND

Sym

bol




Direct PushESN NorthwestPower Probe 9100P


6 ft.~ 58 ft.

Rev

: BW

C


Scr

een

Des

ign

NOTES

20 40

MA

ST

ER

_LO

G_E

21-

222

03.G

PJ

SH

AN

_WIL

.GD

T 3

/14/

16

% Fines (<0.075mm)

% Water Content

BWC

Text Box

A-5 Sheet 1 of 2

BWC

Text Box

A-5 Sheet 2 of 2

BWC

Text Box

A-6 Sheet 1 of 2

BWC

Text Box

A-6 Sheet 2 of 2

BWC

Text Box

A-7 Sheet 1 of 2

BWC

Text Box

A-7 Sheet 2 of 2

BWC

Text Box

A-8 Sheet 1 of 2

BWC

Text Box

A-8 Sheet 2 of 2

BWC

Text Box

A-9 Sheet 1 of 1

BWC

Text Box

A-10 Sheet 1 of 1

8

6

8

4

5

5

4

5

50/5"

50/6"

50/4"

50/5"

50/5"

50/5"

50/4"

50/5"

2 inches asphalt concrete4 inches base courseGrayish brown silty fine to medium sand with

occasional gravel (very dense, moist)(glacially consolidated soils) (till deposits)

(Oxidation staining)

(Hard and rough drilling)

Becomes brownish gray

Grayish brown silt with sand (hard, moist)

(Heavy oxidation staining)

Gray-brown silty fine to medium sand withoccasional gravel and cobbles (very dense,moist)

AC

GP

SM

ML

SM

1

2

3%F

4

5

6

7

8%F

1.0Concrete surfaceseal

Bentonite

2-inch Schedule40 PVC wellcasing

10

15

33

65

Logged By

MAGDrilled

Date Measured

DrillingMethod2/24/2015 2/24/2001

HorizontalDatum

Vertical Datum

DOE Well I.D.: BIS 139A 2 (in) well was installed on 2/24/2015 to a depth of 70 (ft).

3/3/2015Easting (X)Northing (Y)

DrillingEquipment

70.85

Top of CasingElevation (ft) 57.50

Start EndChecked By

43.5

EC-55 Track-Mounted Rig

Elevation (ft)

Groundwater

Driller

Depth toWater (ft)

DTMTotalDepth (ft) Hollow-Stem Auger

Notes:

HammerData

Surface Elevation (ft)Undetermined

Rope & Cathead140 (lbs) / 30 (in) Drop

Boretec 1, Inc.

Steel surfacemonument

Note: See Figure A-1 for explanation of symbols.

FIELD DATA

Dep

th (

feet

)

0

5

10

15

20

25

30

35

Inte

rval

Ele

vatio

n (f

eet)

Co

llect

ed S

amp

le

Rec

over

ed (

in)

Blo

ws/

foot

Gra

phic

Log MATERIAL

DESCRIPTION

Gro

upC

lass

ifica

tion

Wat

er L

evel

Sam

ple

Nam

eT

estin

g

WELL LOG

Moi

stur

eC

onte

nt (

%)

Fin

esC

onte

nt (

%)

Log of Boring B-46-1

901 Harrison Street

Seattle, Washington

20341-003-01

Project:

Project Location:

Project Number:Figure A-2Sheet 1 of 2R

edm

ond:

Dat

e:3/

20/1

5 P

ath:

\\RE

D\P

RO

JEC

TS

\20\

2034

1003

\GIN

T\2

0341

0030

1.G

PJ

DB

Tem

plat

e/Li

bTem

plat

e:G

EO

EN

GIN

EE

RS

8.G

DT

/GE

I8_G

EO

TE

CH

_WE

LL

14.0

BWC

Text Box

A-11 Sheet 1 of 2

4

4

4

3

3

4

6

10

50/4"

50/4"

50/4"

50/3"

50/3"

50/5"

50/6"

50/4"

(Oxidation staining)

Grades to moist to wet(Driller notes soil on auger plug)

(Hard and rough drilling)

(Easier drilling)

Gray fine to coarse gravel with silt andoccasional cobbles (very dense, wet)(cohesionless sand and gravel)

Gray fine to coarse sand with silt andoccasional cobbles (very dense, wet)

GP-GM

SP-SM

9

10

11

12

13%F

14%F

15%F

16%F

54.0

60.0

70.0

70.9

Colorado sandbackfill

2-inch Schedule40 PVC screen,0.010-inch slotwidth

Cone sump tip

10

10

12

12

44

12

8

9

Note: See Figure A-1 for explanation of symbols.

FIELD DATA

Dep

th (

feet

)

35

40

45

50

55

60

65

70

Inte

rval

Ele

vatio

n (f

eet)

Co

llect

ed S

amp

le

Rec

over

ed (

in)

Blo

ws/

foot

Gra

phic

Log MATERIAL

DESCRIPTION

Gro

upC

lass

ifica

tion

Wat

er L

evel

Sam

ple

Nam

eT

estin

g

WELL LOG

Moi

stur

eC

onte

nt (

%)

Fin

esC

onte

nt (

%)

Log of Boring B-46-1 (continued)

901 Harrison Street

Seattle, Washington

20341-003-01

Project:

Project Location:

Project Number:Figure A-2Sheet 2 of 2R

edm

ond:

Dat

e:3/

20/1

5 P

ath:

\\RE

D\P

RO

JEC

TS

\20\

2034

1003

\GIN

T\2

0341

0030

1.G

PJ

DB

Tem

plat

e/Li

bTem

plat

e:G

EO

EN

GIN

EE

RS

8.G

DT

/GE

I8_G

EO

TE

CH

_WE

LL

BWC

Text Box

A-11 Sheet 2 of 2

21-1-22203-001

APPENDIX B

IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL/ENVIRONMENTAL REPORT

of 2 1/2016

SHANNON & WILSON, INC. Geotechnical and Environmental Consultants

Attachment to and part of Report 21-1-22203-001 Date: March 15, 2016 To: Mr. Brian Regan Equinox Properties Corp.

IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL/ENVIRONMENTAL

REPORT

CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR SPECIFIC CLIENTS.

Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant.

THE CONSULTANT'S REPORT IS BASED ON PROJECT-SPECIFIC FACTORS.

A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. Depending on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope-of-service limitations imposed by the client. To help avoid costly problems, ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used: (1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors which were considered in the development of the report have changed.

SUBSURFACE CONDITIONS CAN CHANGE.

Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts; for example, groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events, and should be consulted to determine if additional tests are necessary.

MOST RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS.

Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your consultant can work together to help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be particularly beneficial in this respect.

of 2 1/2016

A REPORT'S CONCLUSIONS ARE PRELIMINARY.

The conclusions contained in your consultant's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction.

THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION.

Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work with other project design professionals to explain relevant geotechnical, geological, hydrogeological, and environmental findings, and to review the adequacy of their plans and specifications relative to these issues.

BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT.

Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final boring logs and data are customarily included in geotechnical/environmental reports. These final logs should not, under any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you, you should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared, and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale.

READ RESPONSIBILITY CLAUSES CLOSELY.

Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in their contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant's liabilities to other parties; rather, they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms Practicing in the Geosciences, Silver Spring, Maryland

308 and 310 9th Avenue North Seattle, Washington

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