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Report (6) II - 4 d uc iaoi/ - co/ ea GEOTECHNICAL INVESTIGATION CARL'S JR. RESTAURANT ' ' I TIGARD, OREGON I j )// � II t II II I. I ►E. OCON{ i � l I i l I l l I l I - N ; i ,EST. NC. GEOTECHNIlC ,L & ENVIRO PREPARED FOR CONSULTANTS I I KWKG WILSONVILLE, OREGON OFFICE COPY i I 1 1 I • APRIL 2011 l I lil I I ' ill i 'iI.I GEOCON NORTHWEST, INC. GEOTECHNICAUENVIRONMENTAL CONSULTANTS IN- Project No. P1811 -05 -01 April 21, 2011 Mr. Dan Gjurgevich KWKG 7263 Lynnwood Court Wilsonville, Oregon 97070 Subject: CARL'S JR. RESTAURANT 11433 SW PACIFIC HIGHWAY TIGARD, OREGON GEOTECHNICAL INVESTIGATION Dear Mr. Gjurgevich: In accordance with our proposal number P10 -05 -115, dated October 25, 2010, and your authorization, Geocon Northwest has performed a geotechnical investigation for the proposed Carl's Jr. restaurant in Tigard, Oregon. The accompanying report presents the findings of the geotechnical investigation and conclusions and recommendations regarding the geotechnical aspects of the proposed project. Based on the results of this investigation, it is our opinion that the project can be constructed as proposed, provided the - recommendations of this report are followed. The primary geotechnical issues addressed herein include grading within the moisture - sensitive soil. If you have questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Sincerely, GEOCON NORTHWEST, INCORPORATED -• - ���4�Q PRoFe• Wesl pa h.D., P.E. c<v w 18281 F •• Sean M. Dixon, C.E.G. Prin • al En ineer --� Project Geologist cc: Mr. Neil Lee, LEEKA A J'' ;' Mr. Chris Kittredge,'Kittr L(; ° ri,g `? Mr. Ron Vandehey ∎ 4' • •Lrrltin"g'.E.rt [feet$ EXPIRATION uATE: i,i v "/42,. I 8283 SW Cirrus Drive is Beaverton, Oregon 97008 o Telephone (503) 626 -9889 m Fax (503) 626-8611 it TABLE OF CONTENTS 1 PURPOSE AND SCOPE 1 2 SITE AND PROJECT DESCRIPTION 1 3 REGIONAL GEOLOGY AND GEOLOGIC HAZARDS 2 3.1 REGIONAL GEOLOGY 2 3.2 LIQUEFACTION POTENTIAL 2 3.3 LATERAL SPREADING 2 3.4 CRUSTAL FAULTS 3 3.5 2009 INTERNATIONAL BUILDING CODE SEISMIC DESIGN CRITERIA 3 4 SUBSURFACE EXPLORATION AND CONDITIONS 4 4.1 SITE EXPLORATION 4 4.2 SUBSURFACE CONDITIONS 4 5 LABORATORY TESTING 5 6 CONCLUSIONS AND RECOMMENDATIONS 6 6.1 GENERAL 6 6.2 SITE PREPARATION 6 6.3 PROOF ROLLING 9 6.4 FILLS 9 6.5 SURFACE AND SUBSURFACE DRAINAGE 9 6.6 FOUNDATIONS 10 6.7 CONCRETE SLABS -ON -GRADE I I 6.8 RETAINING WALLS AND LATERAL LOADS I l 6.9 UTILITY EXCAVAI1ONS 13 6.10 PAVEMENT DESIGN 14 7 FUTURE GEOTECHNICAL SERVICES 16 8 LIMITATIONS 17 MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Site Plan Figure 3, 2009 IBC Response Spectrum APPENDIX A FIELD INVESTIGATION APPENDIX B LABORATORY TESTING • GEOTECHNICAL INVESTIGATION 1 PURPOSE AND SCOPE This report presents the results of the geotechnical investigation for the proposed Carl's Jr. restaurant in Tigard, Oregon. The project site is located at 11433 SW Pacific Highway in Tigard as shown in Figure 1, Site Vicinity. The site is currently occupied by a vacant former Kentucky Fried Chicken (KFC) restaurant with associated paved parking areas and landscaping. The purpose of the geotechnical investigation was to evaluate subsurface soil and geologic conditions at the site and, based on the conditions encountered; provide conclusions and recommendations pertaining to the geotechnical aspects of the proposed restaurant construction. The scope of the investigation consisted of a site reconnaissance, review of published geological literature and the excavation of three exploratory borings. The explorations were advanced to a maximum depth of approximately 16.5 feet below the ground surface (bgs). A detailed discussion of the field investigation is presented in Section 4 of this report. Exploratory logs are presented in Appendix A. Laboratory tests were performed on selected soil samples obtained during the investigation to evaluate pertinent physical properties. Appendix B presents a summary of the laboratory test results, exclusive of the moisture content results. The results of laboratory moisture content tests are presented on the boring logs, located in Appendix A. The recommendations presented herein are based on an analysis of the data obtained during the investigation, laboratory test results, and our experience with similar soil and geologic conditions within the project vicinity. This report has been prepared for the exclusive use of KWKG, and their agents, for specific application to this project, in accordance with generally accepted geotechnical engineering practice. This report may not contain sufficient information for purposes of other parties or other uses. 2 SITE AND PROJECT DESCRIPTION The project site is located at 11433 SW Pacific Highway in Tigard, Oregon. A vacant former KFC restaurant with asphalt parking lot, concrete sidewalks, landscaping and underground utilities currently occupy the site. The topography is relatively flat with elevation change of less than five feet. P1811 -05 -01 - I - April 21, 2011 It is understood that the proposed project will consist of the construction of a new Carl's Jr. restaurant. Structural loads were not available at the time of this report, but it is anticipated that the restaurant will be a single- story, lightly loaded structure. A drive aisle and new restaurant pavement is also proposed. 3 REGIONAL GEOLOGY AND GEOLOGIC HAZARDS 3.1 Regional Geology Based on information obtained from the State of Oregon Department of Mines and Geology Open File Report 0 -90 -2, the site is underlain by the Pliocene to Pleistocene aged Boring Lavas, basalt to basaltic andesite flows that were emitted from a series of local vents. The site is also located in an area that is typically capped with the Portland Hills Silt, a deposit of windblown silt that originated from the Missoula Flood deposits. 3.2 Liquefaction Potential Liquefaction can cause aerial and differential settlement, lateral spreading, and sudden loss of soil shear strength. Soils prone to liquefaction are typically loose, saturated sands and to a lesser degree, silt. Liquefaction susceptible soils typically consist of geologically young alluvial deposits and man -made fills. Studies indicate that soils with more than 10% material by weight finer than 0.002 mm and a liquid limit greater than 32 are not susceptible to liquefaction. Laboratory test results of samples collected from the site show the soils have approximately 22% to 25% grainsize finer than 0.002 mm and a liquid limit between 30 and 40 and, thus are not vulnerable to liquefaction. Additionally, groundwater was not encountered within the borings at the time of drilling. Based on the medium stiff to stiff characteristics of the silt and clay soils encountered, it is estimated that loss of shear strength during a seismic event would be negligible. 3.3 Lateral Spreading Lateral spreading is a liquefaction related seismic hazard that may adversely impact some sites. Areas subject to lateral spreading are underlain by liquefiable sediments and are sloping sites or flat sites adjacent to an open face. In the absence of liquefiable soils, there is negligible potential for lateral spreading at the site. P1811 -05 -01 - 2 - April 21, 2011 3.4 Crustal Faults Based on the literature review, there are no identified faults mapped within the boundaries of the site or within adjacent properties. Evidence was not encountered during the field investigation to suggest the presence of faults within the property. The potential for fault displacement and associated ground subsidence at the site is considered remote. 3.5 2009 International Building Code Seismic Design Criteria Based on the subsurface conditions encountered during the field investigation, it is recommended that the following 2009 International Building Code (IBC) seismic factors and coefficients given in Table 1 be used for seismic design. Figure 3 at the end of this report presents the design response spectra. Table 1: 2009 IBC Seismic Design Recommendations Seismic Variable Recommended Value Site Class D MCE short period spectral 1.07g response accel., S MCE 1- second period spectral 0 59g response accel., SM1 5% damped short period 0.71g spectral response accel., Sos 5% damped 1- second period 0.39g spectral response accel., So, P1811 -05 -01 - 3 - April 21, 2011 11 r 4 SUBSURFACE EXPLORATION AND CONDITIONS 4.1 Site Exploration The subsurface soil conditions at the site were determined based on the literature review, field exploration and laboratory testing. The field exploration was completed on April 7, 2011 and consisted of three exploratory borings. The soil borings were advanced to depths ranging from 11.5 feet to 16.5 feet below the ground surface (bgs). The explorations were completed in the approximate locations shown in Figure 2, Site Plan. 4.1.1 Borings Three borings were completed in the locations of the proposed restaurant and parking lot. A member of Geocon Northwest's geotechnical engineering staff logged the subsurface conditions encountered within the borings. Standard penetration tests (SPT) were performed by driving a 2 -inch outside diameter split spoon sampler 18 inches into the bottom of the boring, in general accordance with ASTM D 1586. The number of blows to drive the sampler the last 12 of the 18 inches are reported on the boring logs located in Appendix A at the end of this report. Disturbed bag samples were obtained from SPT testing. Service providers subcontracted by Geocon Northwest completed the drilling. 4.2 Subsurface Conditions The subsurface explorations were widely spaced across the site and it is possible that some local variations and possible unanticipated subsurface conditions exist. Based on the conditions observed during the reconnaissance and field exploration, the subsurface conditions generally consisted of the following: PAVEMENT — Explorations completed within the pavement generally encountered 5.5- inches of asphalt that was underlain by 6.5- inches of crushed rock. FILL- Stiff, moist, gravelly silt was encountered below the asphalt and baserock in boring B1. Recommendations for non - engineered fill mitigation are provided in subsequent sections of this report. SILTY CLAY TO CLAYEY SILT — Beneath the surface layer, and fill in boring B1, medium stiff to stiff, moist to wet silty clay to clayey silt was encountered to the maximum depth explored. The material generally became more clayey with depth. P1811 -05 -01 - 4 - April 21, 2011 4 i WEATHERED BASALT — Highly weathered basalt was encountered in each boring at depths ranging from 10 to 15 -feet bgs. GROUNDWATER — Static groundwater was not encountered at the time of investigation, however, perched groundwater should be anticipated in unpredictable locations and depths. Subsurface conditions encountered during the field investigation appear to be consistent with geologic conditions mapped within the region. 5 LABORATORY TESTING Laboratory testing was performed on selected soil samples to evaluate moisture content, plasticity, and grain size distribution. Visual soil classification was performed both in the field and laboratory, in general accordance with the Unified Soil Classification System. Moisture content determinations (ASTM D2216) were performed on soil samples to aid in classifying the soil. Grain size analyses were performed on selected samples using procedures ASTM D1140 and ASTM D422. The plasticity index was determined in general accordance with ASTM D4318. Moisture contents are indicated on the boring logs and are located in Appendix A of this report. Other laboratory test results for this project are summarized in Appendix B. P1811 -05 -01 - 5 - April 21, 2011 ' 6 CONCLUSIONS AND RECOMMENDATIONS 6.1 General 6.1.1 It is our opinion that the proposed Carl's Jr. project is geotechnically feasible, provided the recommendations of this report are followed. 6.1.2 Approximately 4 -feet of fill soil was encountered at the location of boring B1. Specific recommendations for non - engineered fill removal can be found in Sections 6.6 and 6.10. 6.1.3 The surface layer of fill soil will need to be evaluated for structural foundation or pavement support. Moisture conditioning and compaction will also be required for material disturbed during site demolition and clearing. Recommendations for both wet and dry weather construction are provided herein. However, dry weather construction is highly recommended and extra costs should be expected if site grading is completed during wet weather. 6.1.4 Existing structures, pavement, and underground utilities should be removed and backfilled with structural fill in proposed building locations. The location of existing underground utilities that will remain should be established to confirm that proposed pavement loads can be accommodated. 6.1.5 Fine - grained, low permeability soil was encountered near the surface which provides the potential for perched groundwater. Recommendations regarding drainage and vapor retarders are provided in subsequent sections of this report. 6.2 Site Preparation Staging areas and haul roads specifically constructed to accommodate anticipated construction loading must be installed by the contractor to minimize future overexcavation of deteriorated subgrade soil. All concrete slab -on -grade and pavement sections presented in the following sections of this report do not include an allowance for construction traffic. The recommended design sections may be "overbuilt" to obtain the necessary working thickness and subsequently reduced to the design section for possible cost savings in lieu of overexcavation of suitable subgrade soil. Alternatively, the working surface may P1811 -05 -01 - 6 - April 21, 2011 1 be incorporated into the final design. Recommendations for wet weather haul roads and working pads should be implemented in all areas of the site that will be subject to construction traffic. 6.2.1 Prior to beginning construction, the areas of the site to receive fill, footings, structural improvements or pavement should be stripped of concrete, asphalt, non - engineered fill, previous subsurface improvements, debris, and otherwise unsuitable material, down to firm native soil. Existing fill soils should be evaluated according to the recommendations provided in Sections 6.6 and 6.10. Excavations made to remove non - engineered fill and previous subsurface improvements should be backfilled with structural fill per Section 6.4 of this report. 6.2.2 Recommendations for both dry weather and wet weather construction are provided in the following sections. However, due to the moisture sensitive near - surface soils, it is recommended that the site be prepared during dry weather. Additional costs will likely be incurred if site grading occurs during wet weather. The owner should obtain a wet weather bid alternative regardless of the time of year site development is planned. 6.2.3 Dry Weather Construction Subgrades in pavement and structural areas that have been disturbed during stripping or cutting operations should be scarified to a depth of at least eight - inches. The scarified soil should be moisture conditioned and compacted to at least 95% of the maximum dry density as determined by ASTM D -1557. Even during dry weather it is possible that some areas of the subgrade will become soft or may "pump," particularly in poorly drained areas. Soft or wet areas that cannot be effectively scarified, moisture conditioned and compacted should be prepared in accordance with Section 6.2.4. 6.2.4 Wet Weather Construction During wet weather, or when adequate moisture control is not possible, it will be necessary to install a granular working blanket to support construction equipment and to provide a firm base on which to place subsequent fills and pavements. The working blanket should consist of an angular crushed rock (six to eight inch maximum size with no more than 5% by weight passing a No. 200 sieve). A member of Geocon Northwest's engineering staff should be contacted to evaluate the suitability of the material before installation. P1811 -05 -01 - 7 - April 21, 2011 I 1 The working blanket should be installed on a stripped subgrade that is covered with a non -woven filter fabric. The rock should be placed in a single lift with trucks end - dumping off an advancing pad of granular fill. It should be possible to strip most of the site with careful operation of track - mounted equipment. However, during prolonged wet weather, or in particularly wet locations, operation of this type of equipment may cause excessive subgrade disturbance. In some areas, final stripping and /or cutting may need to be accomplished with a smooth - bucket trackhoe, or similar equipment, working from an advancing pad of granular fill. After installation, the working blanket should be compacted by a minimum of four complete passes with a moderately heavy static steel drum or grid roller. It is recommended that Geocon Northwest be retained to observe granular working blanket installation and compaction. The working blanket must provide a firm base for subsequent fill installation and compaction. Past experience indicates that a minimum of 12 to 18 inches of working pad is normally required. This assumes that the material is placed on a relatively undisturbed subgrade prepared in accordance with the preceding recommendations. The actual working pad thickness will be highly dependent on the soil moisture characteristics at the time of construction. Areas used as haul routes for heavy construction equipment may require a work pad thickness of two feet or more. In particularly soft areas, a heavy - grade, non - woven, non - degradable filter fabric installed on the subgrade may reduce the thickness of working blanket required. The fabric should have a minimum puncture resistance of 80 pounds and a minimum Mullen Burst strength of 300 psi. Construction practices can affect the amount of work pad necessary. By using tracked equipment and special haul roads, the work pad area can be minimized. The routing of dump trucks and rubber tired equipment across the site can require extensive areas and thicknesses of work pad. Normally, the design, installation and maintenance of a work pad are the responsibility of the contractor. Cement treatment may be a suitable subgrade stabilization technique for the project. Successful cement treatment is dependent upon moisture content of the subgrade soils, weather conditions at the time of treatment, and adequate mixing of the soil and cement. It is recommended that cement treated soils have a three - day, unconfined compressive strength of 250 psi. Cement treatment design is typically the responsibility of the contractor. It is anticipated that a minimum cement content of 5 percent by soil dry weight will be required. P1811 -05 -01 - 8 - April 21, 2011 6.3 Proof Rolling 6.3.1 It is recommended that, prior to on -grade slab construction, the subgrade or granular working blanket be proof - rolled with a fully - loaded 10- to 12 -yard dump truck. Areas of the subgrade that pump, weave, or appear soft or muddy should be scarified, dried and compacted, or overexcavated and backfilled with structural granular fill per Section 6.4. If a significant length of time passes between fill placement and commencement of construction operations, or if significant traffic has been routed over these areas, the subgrade should be similarly proof - rolled before slab construction. It is recommended that a member of our geotechnical engineering staff observe the proof -roll operation. 6.4 Fills 6.4.1 Structural fills should be constructed on a subgrade that has been prepared in accordance with the recommendations in Section 6.2 of this report. Structural fills should be installed in horizontal lifts not exceeding approximately eight inches in thickness and should be compacted to at least 92% of the maximum dry density for the native soils, and 95% for imported granular material. Compaction should be referenced to ASTM D -1557 (Modified Proctor). The compaction criteria may be reduced to 85% in landscape, planter, or other non - structural areas. 6.4.2 During dry weather when moisture control is possible, structural fills may consist of native material, free of topsoil, debris and organic matter, which can be compacted to the preceding specifications. However, if excess moisture causes the fill to pump or weave, those areas should be scarified and allowed to dry. The soil should then be recompacted, or removed and backfilled with compacted granular fill as discussed in Section 6.2 of this report. 6.4.3 During wet - weather grading operations, Geocon Northwest recommends that fills consist of well - graded granular soils (sand or sand and gravel) that do not contain more than 5% material by weight passing the No. 200 sieve. In addition, it is usually desirable to limit this material to a maximum of six inches in diameter for future ease in the installation of utilities. 6.5 Surface and Subsurface Drainage 6.5.1 During site contouring, positive surface drainage should be maintained away from foundation and pavement areas. Additional drainage or dewatering provisions P1811 -05 -01 - 9 - April 21, 2011 • may be necessary if soft spots, springs, or seeps are encountered in subgrades. Where possible, surface runoff should be routed independently to a storm water collection system. 6.5.2 Drainage systems should be sloped to drain by gravity to a storm sewer or other positive outlet. 6.5.3 Drainage and dewatering systems are typically designed and constructed by the contractor. Failure to install necessary subsurface drainage provisions may result in premature foundation or pavement failure. 6.6 Foundations 6.6.1 Where fill soil is encountered in footing bottom locations, the fill should be removed to a minimum of two feet, or to firm native soil, whichever occurs first. The resulting over - excavation should be backfilled to restore grade with structural fill placed in accordance with Section 6.4 of this report. 6.6.2 Footings should be at least 18 inches wide and should extend at least 18 inches below the lowest adjacent pad grade. Foundations embedded within firm native soils or engineered fill may be designed for an allowable soil bearing pressure of 2,500 pounds per square foot (psf). 6.6.3 The aforementioned allowable bearing pressures may be increased by one -third for short term transient loading, such as wind or seismic forces. 6.6.4 Lateral loads may be resisted by sliding friction and passive pressures. A base friction of 35% of the vertical load may be used against sliding. An equivalent fluid weight of 300 pcf may be used to evaluate passive resistance to lateral loads. 6.6.5 Foundation settlements for the loading conditions expected for this project are estimated to be less than one inch, with not more than one -half inch occurring as differential settlement. 6.6.6 A potential for perched or static groundwater is possible during prolonged wet conditions given the presence of fine - grained near surface soils. Geocon Northwest recommends that foundation drains be installed at or below the elevation of perimeter footings to intercept potential subsurface water that may migrate under the building area. P1811 -05 -01 - 10 - April 21, 2011 6.7 Concrete Slabs -on -Grade 6.7.1 Subgrades in floor slab areas should be prepared in accordance with Section 6.2 of this report. Floor slab areas should be proof - rolled with a fully loaded 10- to 12- yard dump truck to detect areas that pump, weave, or appear soft or muddy. When detected these areas should be overexcavated and stabilized with compacted granular fill. Subgrade areas exposing non - engineered fill will require overexcavation and replacement as discussed in Section 6.10.2. 6.7.2 A minimum six -inch thick layer of compacted crushed rock should be installed over the prepared subgrade to provide a capillary barrier and to minimize subgrade disturbance during construction for the on -grade structure. The crushed rock or gravel material should be poorly graded, angular, and contain no more than 5% by weight passing the No. 200 Sieve. 6.7.3 A modulus of subgrade reaction of 150 pci is recommended for design. 6.7.4 The fine - grained near - surface soils at the site have high natural moisture contents and low permeability. These characteristics indicate that high ground moisture may develop under floor slabs during the life of the project. This moisture condition, coupled with differential temperatures and humidity between the subgrade soils and the building interior, can create a differential in vapor pressure between the above- and below -slab environments. The resulting water vapor pressure differential will force migration of moisture through the slab. This migration can result in the loosening of flooring materials attached with mastic, the warping of wood flooring, and in extreme cases, mildewing of carpets and building contents. To retard the migration of moisture through the floor slab, Geocon Northwest recommends installing a 10 -mil polyethylene vapor retarding membrane below the concrete slab. Care should be exercised to ensure that any moisture accumulation on the vapor barrier surface, from either construction activities or precipitation, should be removed prior to the concrete pour. A concrete mix of low water /cement ratio (i.e. less than 0.48) is recommended. Thorough curing of the concrete, using water when possible, should be provided. 6.8 Retaining Walls and Lateral Loads 6.8.1 The tables presented in the following sections summarize the recommendations for design of retaining structures. These values represent estimates of the long -term pressures that will develop in an active or at -rest state of stress. These values do not include an allowance for hydrostatic pressures and assume that retaining P1811 -05 -01 - I I - April 21, 2011 structures will be provided with a drainage system in accordance with subsequent sections of this report. The design parameters in the following sections are for conventional retaining walls and do not include a factor of safety. They also do not include loading from traffic or other surcharges. 6.8.2 Restrained walls are those that are prevented from rotating more than 0.001 H (where H equals the height of the retaining wall portion of the wall in feet) at the top of the wall. Most basements, walls that are rigidly connected to buildings, or walls that make sharp bends fall into this category. Restrained walls should be designed for pressures derived from the criteria provided in Table 3. 6.8.3 Non - restrained walls are not restrained at the top and are free to rotate about the base. Most cantilever retaining walls fall into this category. Non - restrained walls should be designed for pressures derived from the criteria provided in Table 3. 6.8.4 Retaining wall backfill should consist of free - draining granular material. To minimize pressures on retaining walls, the use of open - graded crushed rock backfill with less than 5% by weight passing the No. 200 Sieve is recommended. Retaining wall backfill should be compacted to 90% of ASTM D 1557. Backfill, within approximately five feet of retaining structures, should be compacted with lightweight hand operated equipment. Use of other material and /or over - compaction of the backfill could increase wall pressures. 6.8.5 If backfill is in direct contact with the wall, pressures against the back of the wall can be assumed to act downward at an inclination of 20 degrees from the horizontal. If friction is prevented by drainage membranes or water proofing membranes, the pressures should be assumed to act horizontally. 6.8.6 Foundations or major loads should not be placed in a zone that extends back from the base of a retaining wall at a 1 H:1 V slope. 6.8.7 Retaining walls should be provided with drainage in order to alleviate lateral hydrostatic pressures that may accumulate behind the wall. Retaining wall drains should be positioned near the base of the retaining wall and should be protected by a filter fabric to prevent internal soil erosion and potential clogging. P1811 -05 -01 - 12 - April 21, 2011 4 Table 2: Restrained Wall Design Criteria Backfill Slope Equivalent Fluid Weight Horizontal (H):Vertical (V) (lb /ft Level 60 3H:1V 80 2H:1V 105 Table 3: Non - Restrained Wall Design Criteria Backfill Slope Equivalent Fluid Weight Horizontal (H):Vertical (1/) (lb /ft Level 40 3H:1V 50 2H:1 V 65 6.9 Utility Excavations 6.9.1 Based on the subsurface explorations, difficult excavation characteristics are not expected. It is anticipated that excavation of the site soils will be possible with conventional excavation equipment. 6.9.2 Excavations deeper than four feet, or those that encounter groundwater, should be sloped or shored in conformance with OSHA regulations. Shoring systems are typically contractor designed. 6.9.3 Excavation dewatering may be necessary if substantial flow of water is encountered. Dewatering systems are typically designed and installed by the contractor. 6.9.4 Utilities should be bedded in sand within one conduit diameter in all directions, prior to the placement of coarser backfill. Trench backfill should be lightly compacted within two diameters, or 18 inches, whichever is greater, above P1811 -05 -01 - 13 - April 21, 2011 breakable conduits. The remaining backfill, to within 12 inches of finished grade, should be compacted to 92% of the maximum dry density at optimum moisture as determined by ASTM D 1557. In structural areas, the upper foot of backfill should be compacted to 95% of the maximum dry density. 6.10 Pavement Design 6.10.1 Near - surface soil samples were evaluated to determine pavement design parameters. A CBR of 3 at 95% modified compaction and a resilient modulus of 4,500 psi were used for pavement design based on our experience with similar soils. 6.10.2 The existing fill soils may require additional stabilization prior to the construction of the design pavement section. The proposed stabilization measures would consist of excavating the subgrade soils to a depth of at least 12 inches below design subgrade. Twelve inches of 1 -1/2 inch rock should then be placed and compacted over a geotextile separator fabric to attain the pavement subgrade elevation. The base rock thicknesses presented in Tables 5 and 6 are in addition to the 12 inches of stabilization rock. Other areas of pavement subgrade soil may also require stabilization depending on the conditions at the time of construction. 6.10.3 Alternate pavement designs for both asphalt and portland cement concrete (pcc) are presented in Tables 4 and 5. Pavement designs have been prepared in accordance with accepted AASHTO design methods. A range of pavement designs for various traffic conditions is provided in the tables. The designs assume that the top eight inches of pavement subgrade will be compacted to 95% of ASTM D 1557. Specifications for pavement and base course should conform to current Oregon State Department of Transportation specifications. Additionally, the base rock should contain no more than 5% by weight passing a No. 200 Sieve, and the asphalt concrete should be compacted to a minimum of 92% of ASTM D 2041. Pavement sections were designed using AASHTO design methods, with an assumed reliability level (R) of 90 %. Terminal serviceability of 2.0 for asphalt concrete, and 2.5 for portland cement concrete were assumed. The concrete designs were based on a modulus of rupture equal to 550 psi, and a compressive strength of 4000 psi. The concrete sections assume plain jointed or jointed reinforced sections with no load transfer devices at the shoulder. P1811 -05 -01 - id - April 21, 2011 ft If possible, construction traffic should be limited to unpaved and untreated roadways, or specially constructed haul roads. If this is not possible, the pavement design should include an allowance for construction traffic. Table 4: Asphalt Concrete Pavement Design Approximate Approximate Asphalt Crushed Rock Number of Number of 18 Concrete Base Thickness Trucks per Day Kip Design Axle (each way) Load (1000) Thickness (feet) (feet) Auto Parking 10 0.20 0.7 5 22 0.25 0.7 10 44 0.25 0.9 15 66 0.30 0.9 25 110 0.35 0.9 50 220 0.35 1.0 100 440 0.40 1.1 150 660 0.45 1.1 P1811 -05 -01 - 15 - April 21, 2011 c. Table 5: Portland Cement Concrete Pavement Design Approximate Approximate Crushed Rock Number of Number of 18 P.C.C. Base Thickness Trucks per Day Kip Design Axle Thickness (feet) (feet) (each way) Load (1000) 25 110 0.50 0.5 50 220 0.60 0.5 100 440 0.70 0.5 150 660 0.75 0.5 200 880 0.75 0.5 250 1100 0.75 0.5 7 FUTURE GEOTECHNICAL SERVICES The analyses, conclusions and recommendations contained in this report are based on site conditions as they presently exist, and on the assumption that the subsurface investigation locations are representative of the subsurface conditions throughout the site. It is the nature of geotechnical work for soil conditions to vary from the conditions encountered during a normally acceptable geotechnical investigation. While some variations may appear slight, their impact on the performance of structures and other improvements can be significant. Therefore, it is recommended that Geocon Northwest be retained to observe portions of this project relating to geotechnical engineering, including site preparation, grading, compaction, foundation construction and other soils related aspects of construction. This will allow correlation of observations and findings to actual soil conditions encountered during construction and evaluation of construction conformance to the recommendations put forth in this report. A copy of the plans and specifications should be forwarded to Geocon Northwest so that they may be evaluated for specific conceptual, design, or construction details that may affect the validity of the recommendations of this report. The review of the plans and specifications will also provide the opportunity for Geocon Northwest to evaluate whether the recommendations of this report have been appropriately interpreted. P1811 -05 -01 - 16- April 21, 2011 Y) 8 LIMITATIONS Unanticipated soil conditions are commonly encountered during construction and cannot always be determined by a normally acceptable subsurface exploration program. The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If variations or undesirable conditions are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon Northwest should be notified so that supplemental recommendations can be given. This report is issued with the understanding that the owner, or his agents, will ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project and incorporated into the plans. The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they are due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review should such changes occur. P1811 -05 -01 - 17 - April 21, 2011 ■ t SJ ! • .i . 0 '��' - . j - . j ,, �N Y 11 4 i ` . � ¢ L - 3 i . ' � vb f'.. J x . 3 i - � ,._ 4T� - y ',41--7";7'."4-• 1 -,, , , in t t .. 74 4 v v t I #f ii -'t 4 ' 7 ' ', 1 rt' k d + 1- rX t . f: .. „, „- � '�'1 - r:. }'.''` �.. '.. -: ' _ ,- 4 'L' � ,:, .,, k t s 1 r - - o —� 1 o r `-'' _, y, ( ' y 1 e _ �' L y 1 9 „L 4 -? e-i ;i- f1. 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Uan 3t - •,#.. r ' i' s y y&1> 71 ` 4 ' `. J , 1 3 `. ` •Ya ,r. t u S . t .' - ` x,, - ` - , ' a � r - 7* a A - ! � , r Fer t- thwe t 5 r • ^. st t � , r s 4,1' - 1 ' ' t } - § .i.,:; � v - k . �`Ct c I tw r a r ` _ � , � SIV 8 iyr a ' 1 i - ;T � 4 ` ,7 a ,_ _ 4 b ^ i SNG ?.dt rLYn rx �T' ?u S '?.. h .;_� T a , .� 4 1�s.,... ; ♦ Y ".' 3 : ti," -O.I 1 `' r 'Alt - ' G �, _ •` r `� ,: C 'i'r IL _t.� ' ' ' SN'.sou�n� -,-- Tl y� 't b5-§ .4- # T' ?' p' i • • ; i -. �` • o, (. _. ' _ C , I - ? „ , 5 L §'�° •�' x<� , ..�srza,zs.�;.H, a az u, la�lvs.etev. i� l THE CT TO A LICENSING AGRE G EOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS VID EARTH, i . SU N BJE EM E NT. D THE INFORMATION IS FOR ILLUSTRAT PURPOSES EO BY GOOG ONLY; IT IS NOT INTENDED FOR CLIENTS OR RELIANCE N O T BE REPRODUCED BY CLIENT. CLIENT SHALL INDEMNIFY. DEFEND Af:D USE HOLD HARMLESS GEOCON ACID SHALL FRO'.1 ANY LIABILITY INCURRED AS A RESULT NO SCALE OF SUCH USE OR RELIANCE BY CLIENT. GEOCON VICINITY MAP NORTHWEST INC. GEOTECH AND ENVIRONMENTAL CONSULTANTS CARLS JUNIOR TIGARD 8283 SW CIRRU DRIVE BEAVERTO OREGON 97008 64 43 TIGARD, OREG PHONE 503 626 9889 FAX 503 626 -8611 SD / RS I DSKIE0000 DATE April, 2011 I PROJECT NO. P 1811 - 05 - 0 I FIG. 1 T,F.OKTSP -MEI Sf:'•OXIV ..K R }!,�. �`" �� a '! ' CARLS JUNIOR TIGARD � ' TIGARD, OREGON • 2 z � ____ r r ,. " 114 gy p ' tl I , { .. - : - , . ow� r - , / 1,,. __ ` `" I l" 1 u •,',,i 5 1' °R�� l c • O N ,y- I -- 3 =w . .t ' r ;K? SCALE: 1 . _ 30' s •. 1 - a ; fi . t 1 '' (. . v , '1 I � i • ' } � e 1 E' .� r U T r 1, i r H � " aA r z Jw41� _ ^ �k 7 7 4 u l � S t - r" . II b � gyp �. ,,' - "I• LEGEND x _ R r J" ' Y ' ' x , +a: 1 ' - ' i ,,;•'''' 0 " O . APPROX. SOIL BORING LOCATION " ' ' � • � 4 ,'•a p ' S i ii M -''' - I ' " � '','Y4'.''!'' om, '$ �. , .. — . •�°.. ':_1' : . `4 w Wka � ' aM'="" „ : r Y'. - µ . x y k ' ) - , . z . f fir - .• „. t 7 . • .. „ 8 �n. dt m s + z ,, t- - y..... , - Tr „ ,, b, s +� 1 G 0 NOII IN GEOIEOKCAL CONSULTANTS 6960 FUNDER$DWVE SAN DIEGO, CAIfCO 92)21- 2974 THE 6866661.... 9,FgWaTM. BvauBiE EoR msetAr ..ASRlmvmcoer00oclE Eaten. PH IE858558- 6900 - FA0858558-6 159 SUBIECT TOAUCEtAR THELYEDIA•AT l6 F ORRWA MTNERURFD$ES WAr,RI$ P ROJECT NO P1811 -OS -01 50 IUTEIAED fORCl 505090 REUa10E -- - 1,¢r0EREPROIHKE¢Brcu5rt.CUSI5 F IGURE 2 SM.9eDMO, DEES °aNIKKDW.R uABpfI1'B:eURRE A$A RE$LLt SITE PLAN D ATE APRIL, 201 I Of SUCH USE OR RELIAME BY CuEtrt. I .RUECIM 6d:i1GH:9NSi:14SgS.A. 2009 Oregon Structural Specialty Code Site Class D Design Response Spectrum Tigard Carls Jr 0.8 0.7 - i 0.6 —' 0 0.5 I I i U U 0.4 c � 0 l I 0.3 5% of Critical Dampin a 0.2 0.1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 Period (s) Figure 3 APPENDIX A FIELD INVESTIGATION The field exploration was completed on April 7, 2011 and consisted of three exploratory borings. The soil borings were advanced to depths ranging from 11.5 to 16.5 feet bgs. The explorations were completed in the approximate locations shown in Figure 2, Site Plan. Subsurface logs of the conditions encountered are presented in the following pages. Both solid and dashed contact lines indicated on the logs are inferred from soil samples and drilling characteristics and should be considered approximate. PROJECT NO. P1811 -05 -01 W BORING B 1 >- z o v� } we DE NTH SAMPLE OJ 5 SOIL g Z a �i Z U. NO O z CLASS ELEV. (MSL.) - u o h w FEET N > (USCS) ( DATE COMPLETED 04 -07- 2011 r a ri 0 W cc 2O tx EQUIPMENT TRAILER wISSA BY: S. DIXON a x " ° 0 MATERIAL DESCRIPTION 0 5W ASPHALT CONCRETE over 6'/ :" BASE MATERIAL ML FILL - 2 - e Stiff, moist, dark gray, SILT with tine gravel, very minor grass - - _ BI -I 1 .• _ II 24.2 - 4 - ML NATIVE - - Stiff, moist, light reddish brown, Clayey SILT with black oxides - BI -2 11 27.0 - g _ BI -3 [ _ II 26.9 -Less oxides - 10 - - - - -- - - -- - - -- Bl 4 CL Becomes, Silty CLAY 9 29.3 - - - - 12 - /� - - 14 - - BI -5 ii/K - Becomes wet with gray weathered basalt 9 41.3 - 16 - j - BORING TERMINATED AT 16.5 FEET Figure A -1, P1811 -05- 01.GPJ Log of Boring B 1, Page 1 of 1 SAMPLE SYMBOLS O... SAMPLING UNSUCCESSFUL ® ... STANDARD PENETRATION TEST ® ...'DRIVE SAMPLE (UNDISTURBED) i.. ... DISTURBED OR BAG SAMPLE ® ... CHUNK SAMPLE .. WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON P a' r PROJECT NO. P1811 -05 -01 } w BORING B 2 z -, DEPTH 2 C SOIL F Z L K F J SAMPLE , S Q < CO z u, . Z IN FEET NO. 2 2 CLASS ELEV. (MSL.) DATE COMPLETED 04-07-2011 f- N o a in W D (USCS) W u, O >_ O z _i O ,z„Wo, fr O CC CC EQUIPMENT TRAILER w /SSA BY: S. DIXON a o 0 MATERIAL DESCRIPTION — 0 5W ASPHALT CONCRETE over 61/2' BASE MATERIAL _ •6 o CL NATIVE — 2 — / StitT moist, light reddish brown, CLAY - - - B2 -1 / _ 12 28.5 — 4 — — B2 -2 I - Becomes wet - 9 27.0 - g = B2 -3 -Becomes - 4 29.9 medium stiff, wet to saturated — — 10 — R2-4 — _ — 10 29.7 — 12 — / — / - Becomes stiff — 14 — / — - — BI -5 / -With gray weathered rock 12 56.2 . — 16 — [/ — BORING TERMINATED AT 16.5 FEET Figure A -2, P1811 -05-01.GPJ Log of Boring B 2, Page 1 of 1 ❑ ... SAMPLING UNSUCCESSFUL ® ... STANDARD PENETRATION TEST ® ... DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS ... DISTURBED OR BAG SAMPLE kJ ... CHUNK SAMPLE y ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON c 'l h PROJECT NO. P1811 -05 -01 >- w B ORING B 3 2 LU r , W o DEPTH SAMPLE Q SOIL O t t Z S 1— LL FEET NO. _ 2 Cu ss ELEV. (MSL.) DATE COMPLETED 04 -07.2011 a N 0 w ° a z J = (uses) Z w m o re EQU TRAILER w/SSA BY: S. DIXON a ° v MATERIAL DESCRIPTION - 0 - q 5'/i' ASP1lALT CONCRETE over GYP BASE MATERIAL / MUCL NATIVE — 2 — Stiff, moist, light reddish brown, Silty CLAY to Clayey SILT — B3 -1 — 10 30.1 — 4 — — - — B3 -2 12 28.0 _ 8 _ B3 -3 _ 7 29.5 _ — -Becomes medium stiff _ — 10 — — B3-4 1 - Becomes medium stiff with weathred rock 14 27.9 BORING TERMINATED AT 11.5 FEET Figure A -3, P1811 -05-01.GPJ Log of Boring B 3, Page 1 of 1 SAMPLE SYMBOLS LI ... SAMPLING UNSUCCESSFUL Ii] ... STANDARD PENETRATION TEST 111 ... DRIVE SAMPLE (UNDISTURBED) t":6 ... DISTURBED OR BAG SAMPLE ® ... CHUNK SAMPLE M ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON ,ai u , r APPENDIX B LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples were tested for their moisture content, plasticity, and grain size distribution. Moisture contents are indicated on the boring logs in Appendix A. The results of the grain size distribution tests are presented on the following pages. TABLE B -1 SUMMARY OF PLASTICITY INDEX TEST RESULTS ASTM D4318 Sample Depth Liquid Plastic Plasticity USCS Number (ft) Limit Limit Index Classification B1 -2 5 -6.5 45 23 22 CL B3 -3 7.5 -9 45 21 24 CL z Grain Size Distribution (ASTM D1140 and D 422) Carl's Jr. Tigard Sample B1 -2 Depth = 5 feet I GRAVEL I SAND I SILT I CLAY 100 1 t t; 1 1 i t 1 , 80 -- II I - -- I , — 1 It 1 t I 1 y cn 60 — - t i 1 I I t 1 t I I t 1 1 I , I E; , I I , C. - I I 1 I ° I 1 1 It t I I ! I 1. t 1 I ° t I it 1 I ° I 0 ,... f . . . , . . ,. el . . . I , 100 10 1 0.1 0.01 0.001 Grain size (mm) S Grain Size Distribution (ASTM D1140 and D 422) Carl's Jr. Tigard Sample B3 -3 Depth = 7.5 feet GRAVEL I SAND I SILT I CLAY 100 I _. ° _ it I I i II 0 ° - __ -- I ° ... a a tO I I _° ! I I I I I j I I -- ° -- I � -- I -- 9 — — ,S2 r ti—," ° ° a7 40 — -- — = - - -- - - - ' ai I ° I il! I ° i J 1 1 ' , a f 0 . . . . . , . . , . . . . . . f l . i . . . . . . . • . 100 10 1 0.1 0.01 0.001 Grain size (mm)