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Report (146) �•V - - c\v�t'�J` oY QI L.JL.Y- e ` i• yj :v RhinoOne : APR 0 3 218 GEOTECHNICAL ® � Draft Geotechnical Investigation Report Fields Apartments SW Hunziker Street and SW Wall Street Tigard, Oregon OFFICE COPY Prepared for: DBG Properties LLC Attn: Ms. Melora Banker 2164 SW Park Place Portland, Oregon 97205 December 16, 2016 Project No. DBG-2016-003 RhinoOne Geotechmic& I 4610 NE 77th Avenue#126 Vancouver,WA 98662 I phone 360.2 8.1738 Geotechnical Investigation Report Fields Apartments Tigard, Oregon TABLE OF CONTENTS 1.0 INTRODUCTION 2 2.0 SITE CONDITIONS 2 Site Geology 2 Field Explorations 3 Laboratory Testing 3 Subsurface Conditions 3 Groundwater 4 3.0 GEOTECHNICAL DESIGN RECOMMENDATIONS 4 Discussion 4 Spread Footing Design Recommendations 4 Floor Slab Design Recommendations 5 Seismic Design Criteria 6 Retaining Wall Design Recommendations 6 MSE Walls 6 Other Concrete Retaining Walls 7 Drainage 7 Pavement Design Recommendations 8 Temporary Shoring Design Recommendations 9 4.0 CONSTRUCTION RECOMMENDATIONS 9 Site Preparation 9 Fills on Slopes 10 Slopes 10 Wet-Weather/Wet-Soil Conditions 10 Structural Fills 11 Native Soils 11 Imported Granular Fills 11 Trench Backfill 11 Retaining Wall Backfill 12 Trench Drain and Retaining Wall Drain Backfill 12 Floor Slab Base Rock 12 Pavement Base Aggregate 12 Recycled Concrete, Asphalt and Base Rock 12 Drainage Considerations 13 Foundation Drains 13 Excavation and Temporary Shoring 13 5.0 CONSTRUCTION OBSERVATIONS 14 6.0 LIMITATIONS 14 7.0 RESTRICTIONS 15 SUPPORTING DATA Appendix A—Figures Figure 1 Site Location Map Figure 2 Site Exploration Plan Appendix B—Summary Logs Boring Logs Results of Laboratory Testing RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 1 Geotechnical Investigation Report Fields Apartments • Tigard,Oregon 1.0 INTRODUCTION This report presents Rhino One Geotechnical's (ROG) geotechnical engineering study for the proposed Fields Apartment complex located on an approximately 24 acre site (Washington County Taxlot ID Number 2S1010001600) near the southwest corner of Southwest Hunziker Road and Southwest Wall Street in Tigard, Oregon (Figure 1 — Site Location Map). The proposed plans are for a nine-building 260 unit apartment complex with club house, associated parking, and other miscellaneous improvements located in the southern portion of the lot. Additionally, an office development is planned for the northern end of the lot. The scope of our work is limited to the Apartment Complex. Discussions with the structural engineer indicate the column and perimeter footings loads are on the order of 200 kips and 6 kips per linear foot, respectively. We understand the site will be graded to create flat lots for the buildings. Cuts and fills will therefore be on the order of 10 feet or less. Retaining walls may be required at several locations of the site. Below grade structures are not proposed at this time. This report provides a summary of our field exploration, laboratory testing, geotechnical engineering analysis, geotechnical design criteria, construction recommendations, and seismic design criteria for the proposed project. 2.0 SITE CONDITIONS Site Geology Site geology at the project site was evaluated based on a review of geologic reports, site reconnaissance, and subsurface explorations. Appendix A, Figure 2 (Site Exploration Plan) shows the approximate locations of exploration for this project. The site is located in the Tualatin Valley north of the Willamette River and south of the Tualatin Mountains. The Tualatin Mountains form the physiographic boundary between the Portland Basin to the east and the Tualatin Basin to the west. These basins are part of the larger Puget Sound- Willamette Valley physiographic province, a tectonically active lowland situated between the Coast Range to the west and the Cascade Mountains to the east'. Basement rocks in the vicinity of the site are similar to those exposed in the adjacent Tualatin Mountains, which primarily consist of the Miocene (20 million to 10 million years before present) Columbia River Basalt Group (CRBG). The CRBG consists of thick flows of basalt which have been folded and faulted from the compressional tectonics of the region. Rivers flowing through the Portland Basin eroded channels through the uplifted basalts and deposited alluvium in the adjacent valleys. The lower-most alluvium overlying the CRBG in the site vicinity consists of the glacial-outburst Missoula Flood deposits, deposited approximately 15,500 and 12,500 years ago (Allen et al., 1986)2. Flood waters deposited fine-grained facies consisting of fine sand, silt, and clay in the vicinity of the site. The elevation at the site ranges from approximately 195 feet in the north near SW Hunziker Street, 235 feet near the eastern-center edge of the proposed development, to 180 feet along the southern edge of the site. The surface topography at the site generally slopes towards the west. Existing elevations were determined based on Google Earth maps and should be considered approximate. 1 Orr, E.L.and Orr,W.N. (1999). Geology of Oregon. Kendall/Hunt Publishing, Iowa. Page 254. 2 Allen,J.E., Burns, M.,and Sargent,S. (1986). Cataclysms on the Columbia.Timber Press, Portland. Page 211. RhinoOne Geotechnical 14610 NE 77`h Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 2 Geotechnical Investigation Report Fields Apartments Tigard,Oregon Field Explorations The subsurface exploration program for this project consisted of drilling two (2) borings using a trailer-mounted drill rig and excavating five (5) test pits using a small tracked backhoe, both operated by Dan J. Fischer Excavating, Inc. of Forest Grove, Oregon on November 17, 2016. The borings and test pits were drilled /excavated at the approximate locations shown on the Site Exploration Plan (Figure 2). The borings were advanced using continuous-flight auger drilling techniques. The borings were drilled to a depth of 41.5 feet below ground surface (BGS). Standard Penetration Test (SPT) soil samples were obtained at regular 2.5-foot intervals using a 140-pound Automatic Hammer to a depth of 10 feet and at 5-foot intervals thereafter. Uncorrected blow counts from the SPT sampling are reported on the boring logs. Corrected blow counts [(N1)60] were used for our analysis unless otherwise noted. The five test pits were excavated using a standard hoe and were excavated to a depth of 9.5 feet to 10.6 feet BGS. Bulk soil samples were obtained periodically from the test pit excavated soil. The subsurface materials encountered were logged and field classified in general accordance with the Manual-Visual Classification Method (ASTM D 2488). The SPT and bulk samples were collected at desired depths and packaged in moisture-tight bags. The soil samples were reviewed in the laboratory in order to supplement field classifications. Interpreted borings and test pit logs are attached. Laboratory Testing Laboratory tests were conducted on selected soil samples in accordance with standard ASTM methods. The tests conducted include: • Natural moisture content of selected samples obtained from the borings in general accordance with guidelines presented in ASTM D2216. • Atterberg Limits on selected samples obtained from the borings in general accordance with guidelines presented in ASTM D4318. The results of these tests are presented on the boring and test pit logs and in Appendix B. Subsurface Conditions Two borings and five test pits were completed across the site. The approximate boring locations are shown on Figure 2 of Appendix A. Boring and test pit logs are attached in Appendix B. The borings were drilled to depths of 41.5 feet BGS while the test pits were excavated to depths ranging from 9.5 feet to 10.6 feet BGS. The site generally slopes from east to west and from the center to both south and north. The ground cover of the site consists of grasses and mature trees in the north with blackberry bushes and mature trees in the south. Tree stumps were observed among the blackberry bushes. Historical images from 2011 show mature trees covering the entire site. Subsurface soils consist of the following: • The topsoil consists of sandy silt with a grass-root zone of 6 to 8 inches. • The topsoil is underlain by medium stiff to very stiff, low to medium, clay or silt with varying amounts of fine to medium sand to a depth ranging from 7.5 feet (B-3) to 10 feet BGS (B-7). • The clay/silt was underlain by very loose to loose, low to no plasticity, silty fine to medium sand to a depth ranging from 30 feet BGS (B-3) to 20 feet BGS (B-7). RhinoOne Geotechnical I 4610 NE 77`h Avenue#126 I Vancouver,WA 98662 I phone 360 258 1738 December 16,2016 Project DBG-2016-003 3 Geotechnical Investigation Report Fields Apartments Tigard, Oregon • The silty sand was underlain by medium stiff to very stiff, medium to high plasticity, silty clay below a depth of 30 feet (B-3) to the maximum depth explored of 41.5 feet BGS in B-3. The moisture contents of the samples are generally on the order of 25% to 40%. Groundwater Groundwater was encountered between 8 and 9.5 feet BGS at the time of drilling. Information provided by the US Geological Survey (USGS) Estimated Depth to Groundwater Study of the Portland Metro Area3, along with a review of existing well logs in the area, and the tested moisture contents, indicate the groundwater table is shallow at depths less than 5 feet. 3.0 GEOTECHNICAL DESIGN RECOMMENDATIONS Discussion The proposed plans are for a nine-building 260 unit apartment complex with club house, associated parking, access driveway and other miscellaneous improvements located in the southern portion of the lot. Future developments may include an office building on the north side of the site. The site generally slopes from east to west and from the center to both south and north. The ground cover of the site consists of grasses and mature trees in the north with blackberry bushes and mature trees in the south. Tree stumps were observed amongst the blackberry bushes. The topsoil consists of sandy silt with a grass-root zone of 6 to 8 inches. The root zone for grasses, bushes, and trees should be stripped in the location of the new buildings, roads, and other improvement areas. The project owners should understand some additional over-excavation and replacement may be required during construction if zones of deep roots are encountered during foundation excavation. Any existing utilities below the proposed development areas should either be removed or grouted full in place. We understand the site will be graded to create flat lots for the buildings. We recommend that cuts and fills be limited to 10 feet or less due to presence of shallow groundwater and potential slope stability concerns. Please note, groundwater was encountered at a depth of 8 feet in boring B-3 and 9.5 feet in boring B-7. For cuts and fills greater than 10 feet, additional analysis and individual slope design may be required. Proper drainage may be needed for planned cuts deeper than 5 feet. Un- supported cuts and fills should be limited to slopes of 2H: 1V or flatter. Retaining walls may be required at several locations of the site where these slopes cannot be achieved. We recommend you provide us with a site grading plan when available so we can review these cuts, fills, and retaining walls. Discussions with the structural engineer indicate the column and perimeter footings loads are on the order of 200 kips and 6 kips per linear foot, respectively. Below grade structures are not proposed at this time. These structures can be supported on shallow spread footings. We have provided geotechnical recommendations in the following section of this report which should be incorporated into the design and construction of the proposed new development. Spread Footing Design Recommendations The native soils or the fill prepared in accordance with our recommendations are suitable for support of spread footings. Continuous wall and isolated spread footings should be at least 18 and 24 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the 3 US Geological Survey(USGS).Estimated Depth to Ground Water in the Portland, Oregon Area.Accessed from website http://or.water.us s..ov/.ro"s dir/ouzi on December 12,2015. RhinoOne Geotechnical 4610 NE 77th Avenue#126 i Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 4 Geotechnical Investigation Report Fields Apartments Tigard,Oregon lowest adjacent exterior grade. The bottom of interior footings should be established at least 12 inches below the base of the floor slab. Footings bearing on frim native soils should be sized for an allowable bearing capacity of 2,000 psf. This is a net bearing pressure. The weight of the footing and overlying backfill can be disregarded in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead plus long-term-live loads, and this bearing pressure may be doubled for short-term loads such as those resulting from wind or seismic forces. Based on our analysis, total post-construction settlements were calculated to be less than 1-inch, with post-construction differential settlement of less than 0.5-inch over a 50-foot span for maximum column and perimeter footing loads of less than 200 kips and 6 kips per linear foot. Also, due to the silty nature of these soils, the settlement's will occur fairly rapidly as the loads are applied. Lateral loads on footings can be resisted by passive earth pressure on the sides of the structures and by friction at the base of the footings. An allowable passive earth pressure of 200 pounds per cubic foot (pcf) may be used for footings confined by native soils. Adjacent floor slabs, pavements, or the upper 24 inch depth of adjacent, unpaved areas should not be considered when calculating passive resistance. For footings in contact with native material, use a coefficient of friction equal to 0.35 when calculating resistance to sliding. Both of these numbers include a factor of safety of 1.5. The footings should be founded below an imaginary line projecting at a 1-horizontal to 1-vertical (1 H: 1V) slope from the base of any adjacent, parallel utility trenches. The footings must be embedded so there is a minimum of 10 feet of horizontal distance between the base of the footings and any adjacent slope. In wet-weather, a 2 to 4 inch layer of granular material may be required at the footing base to provide a firm surface for the construction of the new footings. A geotechnical engineer or their representative from ROG should confirm suitable bearing conditions and evaluate footing subgrades. Observations should also confirm loose or soft material, organics, unsuitable fill, and old topsoil zones were removed. Localized deepening of excavations may be required to penetrate deleterious or unsuitable fill materials. The resulting excavations should be backfilled with granular material. Floor Slab Design Recommendations For on-grade slabs on native soils, we recommend a 6-inch-thick layer of imported granular material should be placed and compacted over the prepared subgrade. Imported granular material should be crushed rock or crushed gravel and fairly well-graded between coarse and fine, contain no deleterious materials, have a maximum particle size of 1-inch, and have less than 5-percent by weight passing the U.S. Standard Number 200 Sieve. This material should meet recommendations for "Floor Slab Base Rock" provided in Section 4. A subgrade modulus of 100 pounds per cubic inch (pci) may be used to design the floor slab. The design team should evaluate whether a vapor barrier is needed. A vapor barrier will reduce the potential for moisture transmission through and efflorescence growth on the floor slabs. Additionally, flooring manufacturers often require vapor barriers to protect flooring and flooring adhesives and will warrant their product only if a vapor barrier is installed according to their recommendations. Actual selection and design of an appropriate vapor barrier, if needed, should be based on discussions among members of the design team. RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 5 Geotechnical Investigation Report Fields Apartments • Tigard, Oregon Seismic Design Criteria The seismic design criteria for this project are based on the IBC 2012 (OSSC 2014). A soil profile type "D" can be used for the seismic design of the building based on our exploration. The seismic design criteria, in accordance with the 2012 IBC (OSSC 2014) are summarized in the table below. The code specified IBC Spectra can be used for the design of this building. Table 1 IBC 2012 (OSSC 2014) Seismic Design Parameters Short Period 1 Second Maximum Credible Earthquake Spectral Acceleration SS = 0.973 g Si = 0.422 g Site Class D Site Coefficient Fa= 1.111 F„= 1.578 Adjusted Spectral Acceleration SMG = 1.081 g SM, = 0.666 g Design Spectral Response Acceleration Parameters Sps = 0.720 g SDI = 0.444 g Design Spectral Peak Ground Acceleration 0.283 g Additional Parameters for Liquefaction Analysis per ASCE 7-10, Section 11.8.3 Mapped MCEG Peak Ground Acceleration PGA = 0.425 g Site Coefficient FPGA= 1.075 MCEG Peak Ground Acceleration Adjusted for Site Class PGAM = 0.457 g Groundwater is interpreted at depths on the order of 8 to 9.5 feet BGS. The soils at this site are medium stiff to stiff clayey silt over loose silty sand. The loose silty sands below the water table are moderately susceptible to liquefaction or earthquake-induced settlement during a design level seismic event. The associated vertical settlements could be on the order of 2 to 4 inches during a design level seismic event. Other potential geologic and seismic hazards such as earthquake induced slope instability, differential settlement, surface displacement due to faulting or lateral spreading, and tsunami or seiche inundation are relatively low at this site. Retaining Wall Design Recommendations Retaining walls may be required for accomplishing cuts and fill at the site where adequate slopes cannot be maintained. The retaining walls can be Mechanically Stabilized Earth walls (MSE), typical concrete walls, soil nail walls, or soldier pile walls. At this point, we are not aware of any soil nail or soldier pile walls on this project. These wall types are therefore not discussed any further. We have discussed MSE walls and typical concrete retaining walls below. MSE Walls This section provides general recommendations for the design of MSE walls. MSE walls shall have a minimum reinforcement length of 70 percent of the MSE wall height or 8 feet, whichever is greater. MSE walls shall have a toe embedment equal to 10 percent of the wall height or 2 feet, whichever is greater. The MSE walls should be evaluated for bearing capacity, sliding, overturning, and global stability under static and seismic (pseudo-static) conditions. The MSE walls should be designed using the parameters provided in Table 2. RhinoOne Geotechnical I 4610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 6 Geotechnical Investigation Report Fields Apartments Tigard,Oregon Table 2 Structural Earth Wall Design Parameters Soil Properties Wall Backfill' Retained Soil2 Foundation Soil3 Unit Weight(pcf) 135 110 110 Friction Angle(degree) 35 28 30 Cohesion (psf) 0 0 0 Bearing Capacity(ksf) n/a n/a 5 Acceleration Coefficient,A(g) =2/3 PGAM =0.31 "Wall backfill"shall meet the requirements of"Retaining Wall Backfill"section of this report. 2"Retained soil"shall meet the requirements of ODOT-SS 00330.12—Borrow Material and 00330.13— Selected General Backfill. 3"Foundation soil"shall be dense,native soils prepared in conformance with the"Site Preparation"section of this report. Other Concrete Retaining Walls The retaining wall design recommendations are based on the following assumptions: (1) the walls consist of conventional, cantilevered retaining walls; (2)the walls are less than 10 feet in height; (3) the backfill is drained; and (4) the backfill has a slope flatter than 4H:1 V. Review of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. Any unrestrained retaining walls required for the proposed construction should be designed to resist an active pressure of 35 pounds per cubic foot (pcf) Equivalent Fluid Weight (EFW) in supporting soils with retained slopes less than 4:1 (H:V). An active pressure of 60 pcf EFW should be used for retained slopes with an inclination of 2:1 (H: V). Where retained slopes are greater than 4:1, though less than 2:1, the designer should linearly interpolate between 35 and 60 pcf EFW. For restrained retaining walls an EFW of 60 pcf should be used. Lateral pressures may also be resisted by a passive pressure of 200 pcf EFW assumed to be acting against the sides of the footings (or shear keys, if required). Passive resistance should start at a depth of 1 foot below adjacent grade. For footings in contact with native material, use a coefficient of friction equal to 0.35 when calculating resistance to sliding. Both of these numbers include a factor of safety of 1.5. All retaining walls should also be designed to account for any surcharge loads (e.g. footings, vehicles, etc.) which are applied to the ground surface within a zone extending away from the back of the wall a distance equal to the total height of the wall. Our office should be contacted for appropriate surcharges to be applied to the back of the wall. The actual surcharge distribution and magnitude on the wall will vary depending upon the size and location of the applied load. Drainage The design parameters provided assume back-of-wall drains will be installed in order to prevent buildup of hydrostatic pressures behind all walls. A minimum 12-inch wide zone of drain rock, extending from the base of the wall to within 6 inches of finished grade, should be placed against the back of all retaining walls. Perforated collector pipes should be embedded at the base of the drain rock. The perforated collector pipes should discharge at an appropriate location away from the base of the wall. The backfill material placed behind the walls and extending a horizontal distance equal to at least the height of the retaining wall should consist of granular retaining wall backfill RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 i phone 360.258.1738 December 16,2016 Project DBG-2016-003 7 Geotechnical Investigation Report Fields Apartments Tigard,Oregon material meeting specifications provided in Oregon's Department of Transportation Standard Specifications for Construction 2015 (ODOT-SS) Section 510.12. We recommend the select granular wall backfill be separated from general fill, native soil and/or topsoil using a geotextile fabric which meets the requirements provided in ODOT-SS 2320.20 for drainage geotextiles. The wall backfill should be compacted to a minimum of 92 percent of the maximum dry density, as determined by ASTM D 1557. Backfill placed within 3 feet of the wall should be compacted in lifts less than 6 inches thick using hand-operated tamping equipment (e.g., jumping jack or vibratory plate compactors). Settlements of up to 1% of the wall height commonly occur immediately adjacent to the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend construction of flat work adjacent to retaining walls be postponed at least four (4) weeks after backfilling of the wall, unless survey data indicates settlement is complete prior to that time. Pavement Design Recommendations Our pavement recommendations are based on the following assumptions: • A resilient modulus of 4,500 psi for the native site soils. • A resilient modulus of 20,000 psi estimated for the base rock. • Initial and terminal serviceability index of 4.2 and 2.5, respectively. • Reliability and standard deviation of 85% and 0.45, respectively. • Structural coefficient of 0.42 and 0.10 for the asphalt and base rock, respectively. • We assumed several Equivalent Single Axle Loads (ESALs) for pavement design. The actual ESALs should be selected based on traffic levels anticipated as the project moves forward. If any of these assumptions are incorrect, contact our office with the appropriate information so we may revise the pavement designs. Pavement designs were based on the 1993 AASHTO pavement design equations. The development of pavement designs for the project pavements are in general accordance with the design guidelines and procedures of the American Association of State Highway and Transportation Officials (AASHTO) and the Oregon Department of Transportation (ODOT) Pavement Design Manual. Summary of our pavement design recommendations are in the table below. Table 3 Minimum Pavement Sections Traffic Loading Asphalt Cement Aggregate Base (ESALs) Concrete Rock (inch) (inch) 10,000 (Parking Lots) 3 8 50,000 (Driveways) 4 10 The thicknesses shown in Table 3 are intended to be minimum acceptable values. The asphalt cement (AC) binder should be PG 64-22 Performance Grade Asphalt Cement according to ODOT-SS 00744.11 —Asphalt Cement and Additives. The AC should consist of dense graded Level 3, 1/2-inch hot mix asphalt. The minimum lift thicknesses should be 2.0 inches. The AC should conform to ODOT-SS 00744.13 and be compacted to 91% of Rice Density of the mix, as determined in accordance with ASTM D 2041. RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 8 Geotechnical Investigation Report Fields Apartments Tigard,Oregon The pavement subgrade should be prepared in accordance with the "Site Preparation" and "Structural Fill" sections of this report. Construction traffic should be limited to non-building, unpaved portions of the project site or haul roads. Construction traffic should be prohibited on new pavements. If construction traffic is allowable on newly constructed road sections, an allowance for this additional traffic is necessary in the design pavement section. If moist soil conditions make it difficult to properly moisture condition and compact the roadway subgrade, the use of cement amendment should be considered as alternative to moisture conditioning and compaction. The use of cement amendment will allow for construction of the pavement sections without disturbing the sensitive soil subgrade. If this method is chosen, contact ROG for additional recommendations and alternative pavement sections. Temporary Shoring Design Recommendations Temporary shoring may be required for cuts greater than four feet deep. The selection and design of the temporary shoring system is the responsibility of the contractor. We have provided the following general guidelines for the design of temporary shoring. For a cantilever type shoring system, use an active equivalent fluid weight (EFW) of 35 pounds per cubic feet (pcf) and a passive EFW of 200 pcf. Neglect the upper 2 feet of soils immediately below the base of excavation when calculating passive resistance. Groundwater is indicated to be at depths on the order of 5 to 10 feet BGS. Perched groundwater may be present at shallower depths. Additional pressure due to the presence of groundwater should be accounted for especially if construction is in winter weather. Use a minimum of 2 feet of traffic surcharge load. We are not aware of planned excavations deeper than 10 feet at this time. Additional recommendations will be provided for deeper excavations if needed. 4.0 CONSTRUCTION RECOMMENDATIONS The construction should be carried out as indicated in accordance with the Oregon Department of Transportation Standard Specifications for Construction, 2015 version (ODOT-SS). We assume these specifications will serve, in part, as the project specifications for items contained within and for those not included in this report. Site Preparation The existing near-surface root zone should be stripped and removed from the project site in all proposed building, fill, and pavement areas and for a 5-foot margin around such areas. We anticipate an average stripping depth of 6 to 8 inches with some localized deeper areas. The actual stripping depth should be based on field observations at the time of construction. Stripped material should be transported off site for disposal or stockpiled for use in landscaped areas. Trees and shrubs should be removed from all pavement and improvement areas. In addition, root balls should be grubbed out to the depth of the roots, which could exceed 3 feet BGS. Depending on the methods used to remove the root balls, considerable disturbance and loosening of the subgrade could occur during site grubbing. We recommend soil disturbed during grubbing operations be removed to expose firm undisturbed subgrade. The resulting excavations should be backfilled with structural fill. RhinoOne Geotechnical I 4610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 9 Geotechnical Investigation Report Fields Apartments Tigard, Oregon Demolition should include removal of existing improvements throughout the project site. Underground utility lines, vaults, basement walls, or tanks should also be removed or grouted full if left in place. The voids resulting from removal of footings, buried tanks, etc. or loose soil in utility lines should be backfilled with compacted structural fill. The base of these excavations should be excavated to firm subgrade before filling with sides sloped at a minimum of 1 H:1 V to allow for uniform compaction. Materials generated during demolition of existing improvements should be transported off site or stockpiled in areas designated by the owner. Asphalt, concrete, gravel fill, and base rock materials may be crushed and recycled for use as general fill. Such recycled materials should meet the criteria described in the "Structural Fill" section of this report. Following stripping and prior to placing fill, pavement, or building improvements, the exposed subgrade should be evaluated by proof rolling. The subgrade should be proof rolled with a fully loaded dump truck or similar heavy rubber-tire construction equipment to identify soft, loose, or unsuitable areas. A member of our geotechnical staff should observe the proof rolling. Soft or loose zones identified during the field evaluation should be compacted to an unyielding condition or be excavated and replaced with structural fill, as discussed in the "Structural Fill" section of this report. Fills on Slopes All unretained fills to be placed on slopes steeper than 6 to 1 (horizontal to vertical, H:V) will need to be keyed and benched into competent native materials. Any retained fills will need to be benched in competent native materials. The entire base of all benches should extend into or through competent soils, as identified in the field by representatives from our office. It should be anticipated that the outer edge of bench excavations will extend at least 1 foot below native grade. Keyways should be at least 11/2 times as wide as the compaction equipment, with a width no less than 10 feet. Keyways and benches should be sloped back into the hillside at a minimum 2% gradient. For fills located in drainage swales or where deemed necessary by our personnel, subdrains should be provided within the fill (generally at keyway excavations). Subdrains will typically consist of a minimum 12-inch wide column of drain rock, wrapped with filter fabric, for at least half the height and for the full width of the bench. These systems should drain to 4-inch diameter slotted or perforated pipes, placed at the base of the drain rock. The drain pipes should consist of Schedule 40 PVC, SDR 35, or other similar pipe. Flexible, corrugated pipes should not be used within any drainage system installed as part of this project. A solid line should be used to convey the water to an appropriate discharge point. Slopes Cut slopes less than 10 feet tall and engineered fill slopes may have a maximum gradient of 2:1 (H:V). Cut slopes exceeding 10 feet tall should be approved by our office. Furthermore, we recommend the crest of slopes be rounded (10 foot radius curvature) to reduce surficial sloughing. Wet-Weather/Wet-Soil Conditions Trafficability on the near-surface soils may be difficult during or after extended wet periods or when the moisture content of the surface soil is more than a few percentage points above optimum. Soils which have been disturbed during site-preparation activities, or soft or loose zones identified during probing or proof-rolling, should be removed and replaced with compacted structural fill. Track-mounted excavating equipment may be required during wet weather. The thickness of the granular material for haul roads and staging areas will depend on the amount and type of RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 10 Geotechnical Investigation Report Fields Apartments Tigard,Oregon construction traffic. A 12 to 18 inch-thick mat of imported granular material is sufficient for light staging areas. The granular mat for haul roads and areas with repeated heavy-construction traffic typically needs to be increased to between 18 to 24 inches. The actual thickness of haul roads and staging areas should be based on the contractor's approach to site development and the amount and type of construction traffic. The imported granular material should be placed in one lift over the prepared, undisturbed subgrade and compacted using a smooth-drum, non-vibratory roller. Additionally, a geotextile fabric should be placed as a barrier between the subgrade and imported granular material in areas of repeated construction traffic. The imported granular material should be 4-to 6-inch minus pit run rock with less than 5% passing a Standard #200 sieve. Structural Fills Fills should be placed over subgrade which has been prepared in conformance with the previous section of this report. Material used as structural fill should be free of organic matter or other unsuitable materials and should meet specifications provided in Oregon Department of Transportation Standard Specifications for Construction, 2015 (ODOT-SS), depending upon the application. Discussion of these materials is in the following sections. Native Soils The native soils are suitable for use as general fill, provided it is properly moisture conditioned and meets the requirements of ODOT-SS 00330.12 — Borrow Material, and 00330.13 — Selected General Backfill. When used as structural fill, native soils should be placed in lifts with a maximum un-compacted thickness of 6 to 8 inches and compacted to not less than 92 percent of the maximum dry density as determined by ASTM D 1557. Note that the moisture content of the existing native material is on the order of 25% to 40% percent. This will require considerable moisture conditioning for proper compaction. Imported Granular Fills Imported granular material should be pit or quarry run rock, crushed rock, or crushed gravel and sand and should meet the specifications provided in ODOT-SS 00330.14— Selected Granular Backfill, and ODOT-SS 00330.15 — Selected Stone Backfill. The imported granular material should be fairly well graded between coarse and fine material and have less than 5% by weight passing the U.S. Standard Number 200 Sieve. Imported granular material should be placed in lifts with a maximum non-compacted thickness of 8 to 12 inches and be compacted to at least 92% of the maximum dry density, as determined by ASTM D 1557. During the wet season or when wet subgrade conditions exist, the initial lift should be approximately 18 inches in non-compacted thickness and should be compacted with a smooth- drum roller without using vibratory action. Where imported granular material is placed over wet or soft soil subgrades, we recommend a geotextile be placed as a barrier between the subgrade and imported granular material. The geotextile should meet ODOT-SS 2320.20 for soil separation and/or stabilization. The geotextile should be installed in conformance with ODOT-SS 00350.40 — Geosynthetic Construction. Trench Backfill Trench backfill placed beneath, adjacent to, and for at least 2 feet above utility lines (i.e., the pipe zone) should consist of well-graded, granular material with a maximum particle size of 1.5 inches, have less than 10% by weight passing the U.S. Standard Number 200 Sieve, and meet ODOT-SS 405.12 - Pipe Zone Bedding. The pipe zone backfill should be compacted to at least 90% of the RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 11 Geotechnical Investigation Report Fields Apartments Tigard,Oregon maximum dry density, as determined by ASTM D 1557 or as required by the pipe manufacturer or local building department. Within roadway alignments or beneath building pads, the remainder of the trench backfill should consist of well-graded, granular material with a maximum particle size of 2.5 inches, have less than 10% by weight passing the U.S. Standard Number 200 Sieve, and meet ODOT-SS 405.14 - Trench Backfill, Class B. This material should be compacted to at least 92% of the maximum dry density as determined by ASTM D 1557, or as required by the pipe manufacturer or local building department. The upper 2-feet of the trench backfill should be compacted to at least 95% of the maximum dry density as determined by ASTM D 1557. Outside of structural improvement areas (e.g., roadway alignments or building pads), trench backfill placed above the pipe zone may consist of general fill materials that are free of organics and materials over 6 inches in size, and meet ODOT-SS 405.14 - Trench Backfill, Class A, C, or D. This general trench backfill should be compacted to at least 90% of the maximum dry density, as determined by ASTM D 1557 or as required by the pipe manufacturer or local building department. Retaining Wall Backfill Backfill material placed behind retaining walls and extending a horizontal distance of 0.5H, where H is the height of the retaining wall, should consist of select granular material meeting ODOT-SS 510.12 — Granular Wall Backfill. We recommend the select granular wall backfill be separated from general fill, native soil and/or topsoil using a geotextile fabric which meets the requirements provided in ODOT-SS 2320.20 for drainage geotextiles. The geotextile should be installed in conformance with ODOT-SS 00350.40 — Geosynthetic Construction. Trench Drain and Retaining Wall Drain Backfill Backfill for subsurface trench drains and for a minimum 1-foot-wide zone against the back of retaining walls should consist of drain rock meeting the specifications provided in ODOT-SS 00430.11 — Granular Drain Backfill Material. A pre-fabricated drain board can be substituted for the drain rock. The drain rock should be wrapped in a geotextile fabric meeting the specifications provided in ODOT-SS 2320.20 for soil separation and/or stabilization. The geotextile should be installed in conformance with ODOT-SS 00350.40 — Geosynthetic Construction. Floor Slab Base Rock Base aggregate for floor slabs should be clean, crushed rock or crushed gravel. The base aggregate should contain no deleterious materials, meet specifications provided in ODOT-SS 02630.10 — Dense Graded Aggregate 1"-0", and have less than 5% by weight passing the U.S. Standard Number 200 Sieve. The imported granular material should be placed in one lift and compacted to at least 95% of the maximum dry density, as determined by ASTM D 1557. Pavement Base Aggregate Imported base aggregate for roads and parking lots should be clean, crushed rock or crushed gravel. The base aggregate should meet the gradation defined in ODOT-SS 02630.10— Dense Graded Aggregate 1"-0," with the exception that the aggregate should have less than 5% passing a U.S. Standard Number 200 Sieve. The base aggregate should be compacted to at least 95% of the maximum dry density, as determined by ASTM D 1557. Recycled Concrete, Asphalt and Base Rock Asphalt pavement, concrete, and base rock from the existing site improvements can be used in general structural fills, provided no particles greater than 6 inches are present. It also must be RhinoOne Geotechnical I 4610 NE 77`h Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 12 Geotechnical Investigation Report Fields Apartments Tigard,Oregon thoroughly mixed with soil, sand or gravel such that there are no voids between the fragments. In addition this material should be non-hazardous. Drainage Considerations Newly exposed cut and fill slopes and subgrade surfaces will be susceptible to erosion and should be re-vegetated or otherwise protected as soon as practical after construction. If it is anticipated that an adequate vegetative cover may not be established before the onset of the winter wet season, a heavy mulch cover or erosion netting may be necessary to minimize erosion. Water should not be allowed to pond or stand on any graded pads. Areas that could allow ponding water should be graded and sloped to drain. The surface runoff from graded areas should not be allowed to drain over any slopes. The Contractor shall be made responsible for temporary drainage of surface water and groundwater as necessary to prevent standing water and/or erosion at the working surface. We recommend removing only the foliage necessary for construction to help minimize erosion. The ground surface around the structure should be sloped to create a minimum gradient of 2% away from the building foundations for a distance of at least 5 feet. Surface water should be directed away from all buildings into drainage swales or into a storm drainage system. "Trapped" planting areas should not be created next to any building without providing means for drainage. The roof downspouts should discharge onto splash blocks or paving which direct water away from the buildings, or into smooth-walled underground drain lines that carry the water to appropriate discharge locations at least 10 feet away from any buildings. Foundation Drains We recommend foundation drains around the perimeter foundations of all structures. The foundation drains should be at least 12 inches below the base of the slab. The foundation drain should consist of perforated collector pipes embedded in a minimum 2-foot-wide zone of angular drain rock. The drain rock should meet specifications provided in the "Structural Fill" section of this report. The drain rock should be wrapped in a geotextile fabric. The collector pipes should discharge at an appropriate location away from the base of the footings. Unless measures are taken to prevent backflow into the foundation's drainage system, the discharge pipe should not be tied directly into storm water drain system. Excavation and Temporary Shoring Subsurface conditions at the project site show predominately silts and clays to the depths explored. Excavations in these soils may be readily accomplished with conventional earthwork equipment. Trench cuts should stand vertical to a depth of approximately 4 feet— provided no groundwater seepage is present in the trench walls. Open excavation may be used to excavate trenches with depths between 4 and 8 feet with the walls of the excavation cut at a slope of 1 H:1 V— provided groundwater seepage is not present and with the understanding that some sloughing may occur. The trenches should be flattened to 1.5H:1V if excessive sloughing occurs or seepage is present. If shallow groundwater is observed during construction, use of a trench shield (or other approved temporary shoring) is recommended for cuts extending below groundwater seepage or if vertical walls are desired for cuts deeper than 4 feet. If shoring or dewatering is used, we recommend the type and design of the shoring and dewatering systems be the responsibility of the contractor who is in the best position to choose systems which fit the overall plan of operation. These excavations RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 13 Geotechnical Investigation Report Fields Apartments Tigard,Oregon should be made in accordance with applicable Occupational Safety and Health Administration and State regulations. 5.0 CONSTRUCTION OBSERVATIONS Satisfactory earthwork performance depends on the quality of construction. Sufficient observation of the contractor's activities is a key part of determining if the work is completed in accordance with the construction drawings and specifications. We recommend a geotechnical engineer from ROG be retained to observe geotechnical related construction efforts. Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations discussed above. Recognition of changed conditions requires experience. Therefore, qualified personnel should visit the site with sufficient frequency in order to detect whether subsurface conditions have changed significantly from those anticipated. 6.0 LIMITATIONS This report has been prepared for the exclusive use of the addressee and engineers, and for aiding in the design and construction of the proposed project. It is the addressee's responsibility to provide this report to the appropriate design professionals, building officials, and contractors to ensure correct implementation of the recommendations. The opinions, comments, and conclusions presented in this report were based upon information derived from our literature review, field investigation, and laboratory testing. Conditions between or beyond our exploratory borings may vary from those encountered. Unanticipated soil conditions and seasonal soil moisture variations are commonly encountered and cannot be fully determined by merely taking soil samples or soil borings. Such variations may result in changes to our recommendations and may require additional expenditures be made to attain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs. If there is a substantial lapse of time between the submission of this report and the start of work at the site, if conditions have changed due to natural causes or construction operations at or adjacent to the site, or if the basic project scheme is significantly modified from that assumed, it is recommended this report be reviewed to determine the applicability of the conclusions and recommendations. RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 14 Geotechnical Investigation Report Fields Apartments Tigard,Oregon 7.0 RESTRICTIONS This report is for the exclusive use of the client for design of the development, as described in our proposal for this particular project, and is not to be relied upon by other parties. It is not to be photographed, photocopied, or similarly reproduced, in total or in part, without the expressed written consent of the client and ROG. Sincerely, RhinoOne Geotechnical Christina Hemberry, PE Staff Geotechnical Engineer Rajiv Ali, PE GE (OR) Principal Geotechnical Engineer RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738 December 16,2016 Project DBG-2016-003 15 APPENDIX A Site Location Map Site Exploration Plan • Rh�nO�ne -, Fields Apartments , gilts SW Hunziker Street and SW Wall Street 8_0 ECHNICA[ ' Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 B-3 Drilling Method:Solid-Stem Auger Elevation:Approximately 197 feet AMSL Diameter:4.25-inch auger Water Table:8 feet Logged by:Christina H z in o a S a y a� o Z aa)i [j 5 S F t ,.. �. Materials Description B Remarks g N A o ° o t a P 0 ':' . TP _ Brown,fine sandy SILT;moist(8-inch Root Zone) - — ML Medium stiff,brown,SILT with trace fine sand and - clay;damp,medium plasticity y 1 56 1-3-4 7 30.7 0 5 2 \ 50 2-2-5 7 - 33.4 b 0 Z - •':: SM Loose,brown,silty fine SAND;wet,low to no 3 \ 56 2-2-3 5 plasticity 29.6 w 10-.:::::d , 4 \ 68 2-1-2 3 33.6 CS .1., go ,.:. Becomes very loose,silty fine to medium SAND °x I5 \ 72 1-1-2 3 .`. 32.7 C ;=.."ii - 20—.:• A 6 \ 88 1-1-2 3 - 34.7 3 J \...,:ti 3 r Becomes loose and blue-grey 7 78 2-1-6 7 33.2 TI: 30 ML Soft to medium stiff,blue-grey,fine sandy SILT; 8 88 2-2-2 4 moist,medium plasticity 35.7 '. N Page 3 RhinoOne Fields Apartments SW Hunziker Street and SW Wall Street G E 1 E D-N C A L Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 B-3 Drilling Method:Solid-Stem Auger Elevation:Approximately 197 feet AMSL Diameter:4.25-inch auger Water Table:8 feet Logged by:Christina H z in T G S y p "� 00 6 ' g O _h 0 N 0 s U .5 V Materials Description Remarks 2. 8 a o ° 0 c' 35 %/f CH-MH Stiff to very stiff,blue-grey,clayey SILT;moist, 9 \ 72 4-6-9 15 medium to high plasticity 24.8 ry 40 CH Stiff,blue-grey,CLAY;moist,high plasticity 10 72 3-6-7 13 38.8 Boring terminated at 41.5(feet BGS):boring backfilled with bentonite chips and capped with native soil b 45— M e N — V 2 W _ 50— � I _ Ci 55— 3 � _ 60— o ' 65— I i II _ II Page 4 ��r��®�� , , Fields Apartments _ 1'. SW Hunziker Street and SW Wall Street O—E C H N { 4', Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 B-7 Drilling Method:Solid-Stem Auger Elevation:Approximately 187 feet AMSL Diameter:4.25-inch auger Water Table:9.5 feet Logged by:Christina H z 6 E›+cl. S C p pa o b� 0 °: s C.) .fLI Materials Description Remarks § o o 0 0 a V cn g4 P4 14 a. CA Q C7 0 Brown,fine sandy SILT;moist(6-inch Root Zone) ML l Very stiff,brown,SILT with some fine sand;damp to moist,low to medium plasticity h 1 66 5-8-8 16 18.2 N o 5 Becomes medium stiff,fine sandy SILT 2 44 2-2-3 5 25.8 to go Becomes stiff a 3 \ 78 3-3-8 11 25.2 10 Becomes medium stiff • 4 \ 62 3-3-4 7 31.0 6 0 NL V 2 U 15 Becomes brown with grey mottling s 5 \ 62 2-3-4 7 29.8 w S I 20 - /// CL-ML Soft,blue-grey,clayey SILT with some fine sand; • 6 \ 50 2-2-2 4 / moist,medium plasticity 34.4 3 , 25 cL Stiff,blue-grey,CLAY;moist,medium plasticity ti 7 100 3-4-6 10 % 32.6 LL=40.3% PL=22.8% S PI= 17.5% y � 30 8 \ 100 3-6-12 18 Becomes very stiff 26.1 4 n, Page 5 RhinoOne Fields Apartments alta` SW Hunziker Street and SW Wall Street GEO-ECHNICA_ Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 B-7 Drilling Method:Solid-Stem Auger Elevation:Approximately 187 feet AMSL Diameter:4.25-inch auger Water Table:9.5 feet Logged by:Christina H z o a' 6' s Z pq o z H so H vMaterials Description Y Remarks E 8 a o o a f C4 u; Gq a at 3 Q C7 35 ML Stiff,brown,fine sandy SILT;damp,medium 9 \ 78 3-5-5 10 plasticity 38.5 N - Loose to medium dense,brown,silty fine to coarse 10 \ 62 3-5-5 10 SAND;moist 36.5 Boring terminated at 41.5(feet BGS):boring backfilled with bentonite chips and capped with e – native soil 45— o 0 e .N V U `-V °� 50— o I ! I c.s 55 3 I `c 3 60— h ci y 65— II – Page 6 RRN nmoOne fi=t Fields Apartments �[ l SW Hunziker Street and SW Wall Street • GEO-ECHNICAL Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 TP-I Drilling Method:Test Pit Elevation:Approximately 202 feet AMSL Diameter:24 inch bucket Water Table:NA Logged by:Christina H z in 6 a o °' pa o o a s v H v Materials Description Remarks ° o Q 3 ‹0 3 ? '5 o r24 GQ a P1 C7 0 < < Dark brown,sandy SILT;moist(8-inch Root Zone) CL-ML Red brown,clayey SILT;moist,medium plasticity s C 2 j 0 3 / ry X32.0 LL=36.0% PL=25.5% / PI= 10.8% 4 ML Light brown,fine sandy SILT;damp,low plasticity 6 `i E V 2 27.2 s I 8 •3 I — a I I Test Pit terminated at 9.5(feet BGS):Test pit 10— backfilled with excavated material and lightly tamped in place 4 - I 12— I I Page 1 e 1 Fields Apartments 4, RhinoOne , i&$ SW Hunziker Street and SW Wall Street G E O-E C H N L C A Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 TP-2 Drilling Method:Test Pit Elevation:Approximately 204 feet AMSL Diameter:24 inch bucket Water Table:9.5 feet Logged by:Christina H z a - So o pa o 0 ,u v. s U . F" 2 Materials Description Remarks a cn x a4 as a, as 3 A 0 0 , „ <'<'<' Te Dark brown,sandy SILT;moist(6-inch Root Zone) } ML Light brown,SILT with trace fine sand;moist, medium plasticity b O h 2 N I Q j0 Z ti. 4. 4 1 X 34.5 N (. Becomes SILT with some fine sand w 6 — o a � i C.i -. o 8 2 X 3 3 3 y 1 _ . SM Brown,silty fine SAND;moist,low to no plasticity a = 3 { 29.7 Seepage observed 10 at 9.5 feet U _ Test Pit terminated at 10.6(feet BGS): Test pit backfilled with excavated material and lightly tamped in place 12— I Page 2 khal dnOOne ��, Q Fields Apartments o. 1 SW Hunziker Street and SW Wall Street • G E OT E C H N I CA_ Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 TP-4 Drilling Method:Test Pit Elevation:Approximately 218 feet AMSL Diameter:24 inch bucket Water Table:NA Logged by:Christina H ztip d F S 6 o 2 o S o „ 0 . F" - Materials Description Remarks ain x w a. ca 3 A a" 2 0 `,,.<, TP Dark brown,sandy SILT;moist to wet,low –4>4Y plasticity(8-inch Root Zone) a - ML Brown,fine sandy SILT;moist,medium plasticity 0 G N O C b n 2 — N Q - s m.a s 1 X 4 28.8 LL=33.0% M PL=27.3% 0 PI=5.7% N V 2 _ Becomes SILT with some fine to medium sand, w damp a t 6 o t Ci ,V 82 X26.4 .r A 3 3 3 Q a I 4 – Test Pit terminated at 9.5(feet BGS): Test pit y 10— backfilled with excavated material and lightly g – tamped in place U s 4 12— Page 5 ``� Fields Apartments RhinoOne i13, SW Hunziker Street and SW Wall Street . GEOTECHNICA_ Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 TP-5 Drilling Method:Test Pit Elevation:Approximately 213 feet AMSL Diameter:24 inch bucket Water Table:NA Logged by:Christina H z SoT ° co o r' o Z H UO O wv u U Materials Description a ,04 Remarks '0,0 °$ 0 al ` 6. o cn cn x x as & PI 3 A u' 0 < . s'.'<' TP Dark brown,sandy SILT;moist(6-inch Root Zone) } . ',3- > ML Light brown,SILT with some fine to medium sand; moist,low to medium plasticity U 8 O b O h 2 ti Q 1 I • — 25.3 I 434 Q I 4 a ` SM Brown,silty fine SAND;moist o 2 r ";a 0 m 4 6 ML Light brown,fine sandy SILT;damp,low to - medium plasticity o a 8 —, 1 3 I c 1 I — Test Pit terminated at 9.5(feet BGS): Test pit 10— backfilled with excavated material and lightly s ti _ tamped in place U — to 0 i 12 I — '' III I I — I Page 6 qP F I tnmoOne * Fields Apartments . � Ip,Y SW Hunziker Street and SW Wall Street • GEOTECt i ICA_ , ' Tigard,Oregon Boring Number: Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc. Proj No.:DBG-2016-003 Date:November 17,2016 TP-6 Drilling Method:Test Pit Elevation:Approximately 207 feet AMSL Diameter:24 inch bucket Water Table:NA Logged by:Christina H z cii oh C v o o e 0 = .a s .)0 N ,3;) c .5 Materials Description = Remarks a. o Oca g a8i ' o �o 0 io c 'o c4 v) a PA o. 04 Q c7 0 <'<'<' Ti' Dark brown,sandy SILT;moist(6-inch Root Zone) ML Brown,fine sandy SILT;moist to wet,low to no 0 plasticity 0 1 X22.2 H 0 2 — N oto . ti s I 4 1 o e 0 N – V 0 U 43O t6 Becomes damp t. _ / Ci c S 0 8 — tt 3 j 3 Test Pit terminated at 9.5(feet BGS): Test pit 10— backfilled with excavated material and lightly E..., _ tamped in place s, 12— Page 7 0 APPENDIX B Summary Boring Logs Laboratory Testing 4.0 RhinoOne C_3 E-C J f F-t,H N 1 F A;.... Project Name: Fields Apartments Tested By: RA Project Number: DBG-2016-003 Laboratory No: 2016-00005 Date 20-Nov-16 OVEN DRY MOISTURE CONTENT- ASTM D 2216 Sample ID: B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 Depth: 2.5-4 5-6.5 7.5-9 10-11.5 15-16.5 20-21.5 25-26.5 30-31.5 35-36.5 40-41.5 Tare Number: 001 002 013 003 004 014 015 016 017 026 Weight of Tare (Wt.): 51.25 51.58 50.26 51.25 50.6 51.22 51.55 51.66 51.69 51.42 Weight of Tare+Wet Soil: 161.17 163.44 165.55 168.17 185.4 178.68 172.58 146.33 177.63 146.11 Weight of Tare+ Dry Soil: 135.36 135.44 139.22 138.78 152.2 145.85 142.4 121.44 152.64 119.66 Weight of Dry Soil: 84.11 83.86 88.96 87.53 101.6 94.63 90.85 69.78 100.95 68.24 Weight of water: 25.81 28 26.33 29.39 33.2 32.83 30.18 24.89 24.99 26.45 Water Content(%): 30.7% 33.4% 29.6% 33.6% 32.7% 34.7% 33.2% 35.7% 24.8% 38.8% Soil Description: IR9{� tnoOne EC) f :;I I JIC w Project Name: Fields Apartments Tested By: RA Project Number: DBG-2016-003 Laboratory No: 2016-00005 Date 20-Nov-16 OVEN DRY MOISTURE CONTENT- ASTM D 2216 Sample ID: B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7 Depth: 2.5-4 5-6.5 7.5-9 10-11.5 15-16.5 20-21.5 25-26.5 30-31.5 35-36.5 40-41.5 Tare Number: 005 018 006 007 008 019 020 021 022 023 Weight of Tare (Wt.): 51.72 51.58 51.12 51.56 51.82 51.37 51.76 51.01 51.79 51.7 Weight of Tare+Wet Soil: 186.92 152.27 169.3 178.82 167.6 167.81 170.03 172.59 145.24 161.59 Weight of Tare+ Dry Soil: 166.11 131.63 145.5 148.68 141.04 138.02 140.93 147.44 119.26 132.19 Weight of Dry Soil: 114.39 80.05 94.38 97.12 89.22 86.65 89.17 96.43 67.47 80.49 Weight of water: 20.81 20.64 23.8 30.14 26.56 29.79 29.1 25.15 25.98 29.4 Water Content (%): 18.2% 25.8% 25.2% 31.0% 29.8% 34.4% 32.6% 26.1% 38.5% 36.5% Soil Description: 4 Rnoone GPO.I_.['ICH N1(_:; L Project Name: Fields Apartments Tested By: RA Project Number: DBG-2016-003 Laboratory No: 2016-00005 Date 20-Nov-16 OVEN DRY MOISTURE CONTENT- ASTM D 2216 Sample ID: TP-1 TP-1. TP-2 TP-2 TP-4 TP-4 TP-5 TP-6 Depth: 2.5-3.5 7-7.5 4-5 9.5-10 3.5-4 8-8.5 2.5-3 1.5-2 Tare Number: 027 009 011 028 029 030 031 032 Weight of Tare (Wt.): 51.54 51.49 51.61 51.48 51.8 51.68 51.68 51.45 Weight of Tare+Wet Soil: 160.16 160.2 179.4 168.66 173.27 157.94 175.29 190.1 Weight of Tare+ Dry Soil: 133.82 136.98 146.61 141.8 146.08 135.76 150.35 164.88 Weight of Dry Soil: 82.28 85.49 95 90.32 94.28 84.08 98.67 113.43 Weight of water: 26.34 23.22 32.79 26.86 27.19 22.18 24.94 25.22 Water Content (%): 32.0% 27.2% 34.5% 29.7% 28.8% 26.4% 25.3% 22.2% Soil Description: Atterberg Limits (ASTM D4318,AASHTO 189/90) Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658 Exploration Number: Fields B-7 Sample No.: Depth: 25.0-26.5 Date: 12/14/2016 Tested By: MTR Checked by: USCS Symbol Description of Soil: Medium Brown Clay CL Natural Moisture Can# Wt.of wet Wt of dry soil Wt.of can Moisture Wt.of dry Moisture Content soil and can(g) and can(g) (g) loss(g) soil(g) Content(%) 1555.50 1352.50 658.70 203.00 693.80 29.3 Liquid Limit Test . ; , _ T - w e ., 2 3. 5 ,, 4 . . . 5 Container Number 6 20 19 Number of Blows 34 23 16 Wt.of wet soil and can(g) 34.93 34.5 33.45 Wt.of dry soil and can(g) 31.28 30.59 29.79 Wt.of can(g) 21.42 21.08 21.40 Moisture loss(g) 3.65 3.91 3.66 Wt.of dry Soil(g) 9.86 9.51 8.39 Moisture Content% 37.0 41.1 43.6 Plastic Limit Test 1 2 Container Number 18 17 Calculation Wt.of wet soil and can(g) 24.56 24.59 Liquid Limit 40.3 Wt.of dry soil and can(g) 23.94 23.99 Plastic Limit 22.8 Wt.of can(g) 21.28 21.30 Plasticity Index 17.5 Moisture loss(g) 0.62 0.60 Wt.of dry soil(g) 2.66 2.69 Moisture Content% 23.3 22.3 l Liquid Limit Determination Plasticity Chart 60 : 90 :.. ._.._. _._._ _.._ :..._.:: z i CH 80 _. :: 50 ! ( 1i 0 7Q v.� ..... ...... _ =40 CL ` i I 60 .. d 1 c x 0 50 _ _ _._. �: c 30 t u i II' L N l 2 30 20 MH&OH 20i 10 10 n Mi ! ML&OL Q .._. .... .. _. Q :..._ _ -- 10 20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100 No.of Blows Liquid Limit,LL(%) K. Atterberg Limits (ASTM D4318,AASHTO T89/90) Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658 Exploration Number: Fields TP-1 Sample No.: Depth: 2.5-3.0 Date: 12/14/2016 Tested By: MTR Checked by: USCS Symbol Description of Soil: Medium Brown Clayey Silt ML& OL Natural Moisture Can 5 Wt.of wet Wt.of dry soil Wt.of can Moisture Wt.of dry Moisture Content soil and can(g) and can(g) (g) loss (g) soil(g) Content(%) 1283.30 1157.30 742.70 126.00 414.60 30.4 Liquid Limit Test 1 2 3 4 - 1 5 ` Container Number 23 22 5 Number of Blows 17 24 33 Wt.of wet soil and can(g) 34.46 36.65 36.68 Wt.of dry soil and can(g) 30.93 32.76 32.70 Wt.of can(g) 21.39 21.45 21.83 Moisture loss(g) 3.53 3.89 3.98 Wt.of dry Soil(g) 9.54 11.31 10.87 Moisture Content% 37.0 34.4 36.6 Plastic Limit Test 1, 2 Container Number 1 21 Calcu n Wt.of wet soil and can36.0 (g) 28.58 28.27 Liquid Limit Wt. dryof soil and can252 (g) 27.04 26.87 Plastic Limit Wt.of can(g) 20.95 21.30 Plasticity Index 10.8 Moisture loss(g) 1.54 1.40 Wt.of dry soil(g) 6.09 5.57 Moisture Content% 25.3 25.1 Liquid Limit Determination Plasticity Chart ' i ! CH , 50 80 .. _ :. ...... CL 70 40 , i 6o 0. 50o __.. 'c 30 ' : - - ; : • ' N 40 E 30 A 20 _::: a 20 _.... ___.. ...... i MC&OX : v 10 n-m� ML;&OL 10 20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100 No.of Blows Liquid Limit,LL(%) Atterberg Limits (ASTM D4318,AASHTO T89/90) Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658 Exploration Number: Fields TP-4 Sample No.: Depth: 3.5-4.0 Date: 12/9/2016 Tested By: MTR Checked by: USCS Symbol Description of Soil: Medium Brown Silt ML &OL Natural Moisture Can# Wt.of wet Wt.of dry soil Wt.of can Moisture Wt.of dry Moisture Content soil and can(g) and can(g) (g) loss(g) soil(g) Content(%) 1220.70 1055.40 461.70 165.30 593.70 27.8 Liquid Limit Test - . 1 ‘-. - -,,..' 2 .- . ..'..- I',:3 ,'-:-. - -;. 4 , ,\.S ''','"'. ''',;:-''5'.'•••:- -n,, Container Number 8 13 2 25 17 34 Number of Blows 38.55 35.00 35.72 Wt.of wet soil and can(g) 34.31 31.41 32.23 Wt.of dry soil and can(g) 21.46 21.24 20.79 Wt.of can(g) 4.24 3.59 349 Moisture loss(g) 1285 10.17 11.44 Wt.of dry Soil(g) 33.0 35.3 30.5 Moisture Content% Plastic Limit Test 1 , ,. - 2 ,.,. .: 14 4 Container Number ". ' '..'S''' ' Calculation .'. - ,..::-7'.'...-•'.'':k7::4'.' 28.70 28.65 33.0 Wt.of wet soil and can(g) Liquid Limit 27.05 27.11 27.3 Wt.of dry soil and can(g) Plastic Limit 21.52 5.7 Wt.of can(g) 20.96Plasticity Index 1.65 1.54 Moisture loss(g) 6.09 5.59 Wt.of dry soil(g) 27.1 27.5 Moisture Content% Liquid Limit Determination Plasticity Chart 100 60 , . ; . : . 1 : • . : i i , i : I . . • . ..... • i . 1 i i . -'L' i - • .1 20 • ' ' ' ' ' ' ' ' '. ; 1.0 0 10 20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100 No.of Blows liquid Limit,LL(%)