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HomeMy WebLinkAboutDERR-2025-006051 Preliminary Geotechnical Engineering Report Former Fleet Facility Salt Lake City, Utah September 6, 2012 Terracon Project No. 61125059 Prepared for: Salt Lake City Corporation Salt Lake City, Utah Prepared by: Terracon Consultants, Inc. Bluffdale, Utah TABLE OF CONTENTS Page EXECUTIVE SUMMARY ............................................................................................................ 1 PRELIMINARY GEOTECHNICAL ENGINEERING REPORT ..................................................... 1 1.0 INTRODUCTION ............................................................................................................. 1 2.0 PROJECT INFORMATION ............................................................................................. 1 2.1 Project Description ............................................................................................... 1 2.2 Site Location and Description............................................................................... 2 3.0 SUBSURFACE CONDITIONS ........................................................................................ 2 3.1 Typical Subsurface Profile ................................................................................... 2 3.2 Groundwater ........................................................................................................ 3 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ...................................... 3 4.1 Geotechnical Considerations ............................................................................... 3 4.2 Earthwork............................................................................................................. 4 4.2.1 Site Preparation........................................................................................ 4 4.2.2 Material Requirements ............................................................................. 4 4.2.3 Compaction Requirements ....................................................................... 5 4.2.4 Utility Trench Backfill ................................................................................ 5 4.2.5 Grading and Drainage .............................................................................. 6 4.2.6 Construction Considerations..................................................................... 6 4.3 Foundations ......................................................................................................... 7 4.3.1 Design Recommendations........................................................................ 7 4.3.2 Alternative Foundation Support ................................................................ 8 4.3.3 Construction Considerations..................................................................... 8 4.4 Seismic Considerations........................................................................................ 9 4.5 Floor Slab .......................................................................................................... 10 4.5.1 Design Recommendations...................................................................... 10 4.5.2 Construction Considerations................................................................... 11 5.0 GENERAL COMMENTS ............................................................................................... 11 APPENDIX A – FIELD EXPLORATION Exhibit A-1 Project Vicinity Map Exhibit A-2 Boring Location Plan Exhibit A-3 to A-6 Boring Logs Exhibit A-7 Field Exploration Description APPENDIX B – LABORATORY TESTING Exhibit B-1 Laboratory Testing Exhibit B-2 to B-5 Consolidation Test Exhibit B-6 to B-9 Triaxial Test APPENDIX C – SUPPORTING DOCUMENTS Exhibit C-1 General Notes Exhibit C-2 Unified Soil Classification System APPENDIX D – BEARING PRESSURE CHARTS Exhibit D-1 Net Allowable Bearing Pressures Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 1 EXECUTIVE SUMMARY This geotechnical executive summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. A preliminary geotechnical exploration has been performed at Salt Lake City’s former fleet facility located at 850 South 300 West in Salt Lake City, Utah. Four (4) borings, designated B- 01 through B-04, were performed to depths ranging from approximately 41½ to 76½ feet below the existing ground surface. Additional geotechnical explorations and final recommendations should be completed once final building(s) layout and loads have been determined. The following geotechnical considerations were identified and should be considered for redevelopment planning purposes: „ Site Soils: The near surface site soils generally consist of about 2 to 4 feet of fill material underlain by silty clay to clay. The fill material appeared to consist of silty gravel with sand. Debris was encountered within the fill at B-04. The underlying subsurface soils generally consisted of clay with sand, sandy silty clay and sand to the maximum depth explored. Groundwater was encountered at depths of approximately 12 to 15 feet in the borings during drilling. „ Foundations: Spread footing foundations bearing on undisturbed native soil or on structural fill may be considered for the support of lightly loaded structures. Alternative foundation support systems that may be considered to increase the allowable bearing capacity include rammed aggregate piers, or grouted columns placed under footings. Deep foundations, such as driven piles or drilled shafts, may be needed for structures with large loads, parking levels or below-grade levels. „ Floor Slab: Construction of concrete slabs-on-grade should be supported on a minimum of 4 inches of crushed gravel over properly placed and compacted structural fill or properly prepared native soil. „ Seismic: The 2009 International Building Code (IBC), Table 1613.5.2 seismic site classification for this site is F. Liquefaction induced settlement on the order of 2 to 4 inches expected during a design earthquake event at the site. „ Earthwork: Existing fill, and other debris and deleterious materials should be removed and replaced with properly placed and compacted structural fill within foundation, floor slab and Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 2 pavement areas. Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support. We therefore recommend that Terracon be retained to monitor this portion of the work 1 PRELIMINARY GEOTECHNICAL ENGINEERING REPORT FORMER FLEET FACILITY 850 SOUTH 300 WEST SALT LAKE CITY, UTAH Terracon Project No. 61125059 September 6, 2012 1.0 INTRODUCTION A preliminary geotechnical exploration has been completed Salt Lake City’s former fleet facility located at 850 South 300 West in Salt Lake City, Utah. Four (4) borings, designated B-01 to B- 04, were performed to depths ranging from approximately 41½ to 76½ feet below the existing ground surface. Logs of the borings along with a project vicinity map, and boring location plan are included in Appendix A of this report. The purpose of the exploration was to provide information and preliminary geotechnical engineering recommendations for use in redevelopment planning relative to: „ subsurface soil conditions „ foundation design and construction „ depth to groundwater „ floor slab design and construction „ earthwork „ seismic considerations Once redevelopment planning has been completed and final building(s) layout and loads have been determined additional geotechnical explorations and final recommendations should be completed. 2.0 PROJECT INFORMATION 2.1 Project Description Item Description Structures Specific details regarding the type and location of structures for the redevelopment are unknown. Results of this scope of work will assist Salt Lake City Corporation in planning appropriate facilities for the redevelopment. Based on discussions with the client, we understand that redevelopment of the property may include one or more single-story to over four story buildings and associated parking lots and access drives. Building construction Wood or metal framed. (assumed) Finished floor elevation Near existing grade. (assumed) Maximum structure loads Columns: 200 kips (assumed) Walls: 4 klf (assumed) Slabs: 150 psf max (assumed) Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 2 Item Description Maximum allowable settlement Columns: 1-inch (assumed) Walls: ¾ inch over 40 feet (assumed) Grading Minimal cuts or fills, assumed to be less than 2 feet. Cut and fill slopes None. Free-standing retaining walls None. (assumed) Below Grade Areas None. (assumed) 2.2 Site Location and Description Item Description Location This project includes the property located in Salt Lake City, Utah between 800 South and 900 South, from 300 West to 400 West. The site includes most of the full city block with the exception of a small parcel located on the southwest corner. Existing improvements The property is currently occupied by the Salt Lake City Corporation Fleet Facility. The majority of the site is covered with asphaltic concrete pavement. Existing buildings are located on the east, south and north portions of the property. Current ground cover Existing asphaltic concrete pavement and buildings. Existing topography Relatively level project site. Mapped liquefaction potential The site is mapped having a high liquefaction potential. Liquefaction Special Study Areas, Wasatch Front and Nearby Areas, compiled by Gary E. Christenson and Lucas M. Shaw, 2008, Supplement Map to Utah Geological Survey Circular 106. 3.0 SUBSURFACE CONDITIONS 3.1 Typical Subsurface Profile Specific conditions encountered at each boring location are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs included in Appendix A of this report. Based on the results of the borings, subsurface conditions on the project site can be generalized as follows: Stratum Approximate Depth to Bottom of Stratum (feet) Material Description Consistency/Density 1 4 to 6 inches Asphalt -- 2 2 to 4 Fill: gravel with silt and sand and some debris -- 3 41½ a to 64 Clay to Clay with Sand Very Soft to Medium Stiff 4 70 to 76½ b Sandy Silty Clay Stiff to Very Stiff Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 3 Stratum Approximate Depth to Bottom of Stratum (feet) Material Description Consistency/Density 5 76 b Sand Very Loose a Termination depth of B-01 and B-02 b Maximum depth explored Laboratory tests were conducted on selected soil samples and the test results are presented in Appendix B and on the boring logs. Moisture contents of the native soils ranged from 18 to 58 for soils tested. Liquid limits and plasticity indexes ranged from 22 to 49 percent and 6 to 24 percent respectively. 3.2 Groundwater Groundwater was encountered between depths of 12 to 15 feet in the borings at the time of the field exploration. The groundwater level readings do not necessarily represent stabilized groundwater levels. It should be recognized that fluctuations of the groundwater table may occur due to seasonal variations in the amount of rainfall, runoff, future construction and other factors not evident at the time the borings were performed. Evaluation of these factors is beyond the scope of this exploration. 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION 4.1 Geotechnical Considerations In our opinion, the site appears suitable for redevelopment from a geotechnical engineering perspective provided the recommendations presented in this geotechnical report are followed. Additional geotechnical explorations and final recommendations should be completed once final building(s) layout and loads have been determined. Shallow strip and spread footing foundations bearing on native undisturbed soil or on properly placed and compacted structural fill may be considered for support of lightly loaded structures, generally one to two story buildings. Structures with moderate loading, generally over two stories, may require the use of rammed aggregate piers or grouted columns to control settlement and increase bearing capacity. Heavily loaded structures, multi-story or structures with parking levels or below grade levels may require deep foundations, such as driven piles or drilled shafts to support the loads and limit settlement. Existing granular fill consisting of gravel with sand, varying amounts of silt and some debris was encountered at the site to a depth of about 2 to 4 feet. Existing fill should be removed from below structures. The existing fill may be reused as structural fill or grading fill provided it is tested and meets the requirements of this report. Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 4 The seismic site class for this site is F due to the presence of liquefiable soils. Site class factors may be determined using Site Class E, for structures with fundamental periods of 0.5 seconds or less, as explained in section 4.4 of this report. Structures with larger fundamental periods will require a site specific seismic analysis. Liquefiable soils were encountered at the site. Liquefaction induced settlement is estimated to be on the order of 6 inches during a 2 percent in 50 year seismic event. Preliminary geotechnical engineering recommendations for foundation systems and other earth connected phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project. 4.2 Earthwork 4.2.1 Site Preparation Prior to construction or placement of new fill, all existing fill, disturbed native soil, construction debris including concrete slabs, existing foundations and utilities, and any otherwise unsuitable material should be removed from below planned foundation, floor slab and pavement areas. Exposed subgrade soils should proof-rolled to aid in locating soft or unstable areas. Soft or unstable areas encountered during proof-rolling should be excavated and replaced with compacted structural fill or stabilized using geotextiles in combination with crushes stone. Care should be taken during excavation to reduce the potential for disturbance of the native soils. Geotextiles and separation fabric in combination with clean crushed angular stone may be required to form a stable working platform for construction. Although evidence of fills deeper than approximately 4 feet, or underground facilities such as septic tanks, cesspools, basements, and utilities was not observed during the site reconnaissance, such features could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. 4.2.2 Material Requirements Soils for use as fill should meet the following requirements: Fill Type 1 USCS Classification Acceptable Location for Placement Structural Fill GM to SM 2 All locations and elevations Grading Fill GM to SM3 Non-structural areas Stabilization Fill --4 Pavement or foundation areas. 1. Fill should consist of approved materials that are free of organic matter and debris. Frozen material should not be used, Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 5 and fill should not be placed on a frozen subgrade. A sample of each material type should be submitted to Terracon for evaluation. 2. Well graded granular soil with a maximum particle size of 3 inches, a liquid limit less than 30 and a plasticity index (PI) of less than 6, with 25 to 60 percent passing the No. 4 sieve and having less than 15 percent fines. 3. Granular soil with a maximum particle size of 4 inches, a liquid limit less than 30 and a plasticity index (PI) of less than 6, and having less than 30 percent fines. 4. Clean crushed angular rock, 3 to 4 inch minus, with less than 5 percent fines. Existing fill soils encountered in the borings are classified as gravel with sand and varying amounts of silt. The existing fill may be reused as structural fill or grading fill provided it is tested and meets the requirements above and does not contain any debris or deleterious material. 4.2.3 Compaction Requirements Item Description Fill Lift Thickness 8 inches or less in loose thickness Compaction Requirements 1 95% of the material’s maximum dry density (modified Proctor – ASTM D1557) in foundation, floor slab and pavement areas; 92% of the maximum dry density in other non-structural areas of fill and backfill. Moisture Content Within 2% of the optimum moisture content 1. We recommend that structural fill be tested for moisture content and compaction during placement. Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved. Stabilization rock should be compacted to seat the rock in place. This can be accomplished by tamping with the bucket of an excavator, or static rolling the rock. Excessive or vibratory compaction may disturb underlying clay soils and should not be permitted. Terracon should be contacted to review exposed subgrade conditions and provide stabilization recommendations. 4.2.4 Utility Trench Backfill All trench excavations should be made with sufficient working space to permit construction including backfill placement and compaction. It is anticipated that shallow trenches and excavations for the project can be made with conventional earth moving equipment. Near surface site soils include mainly fine-grained soils (OSHA C). Cut slopes should not be constructed steeper than 1½ horizontal to 1 vertical. Some excavations less than 4 feet deep in cohesive soil may stand at, or near vertical. However, at any of these slopes, some raveling or caving may occur and should be expected, especially if the slope dries or becomes wet. Flatter slopes may be required if excessive raveling occurs or if seepage is encountered. Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 6 4.2.5 Grading and Drainage All grades must be adjusted to provide positive drainage away from buildings during construction and maintained throughout the life of the proposed structures. Infiltration of water into utility trenches or foundation excavations should be prevented during construction. In areas where sidewalks or paving do not immediately adjoin structures, we recommend that protective slopes be provided with a minimum grade of approximately five percent for at least 10 feet from perimeter walls. The use of swales, chases and/or area drains may be required to facilitate drainage in unpaved areas around the perimeter of buildings. Backfill against footings, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. After building construction and prior to project completion, we recommend verification of final grading be performed to document positive drainage, as described above, has been achieved. Planters located adjacent to structures should preferably be self-contained or eliminated. Sprinkler systems should not be installed within five feet of foundation walls. Roof drains should discharge onto pavements or be extended away from structures a minimum of 10 feet through the use of splash blocks or downspout extensions. A preferred alternative is to have the roof drains discharge to storm sewers by solid pipe or daylighted to a detention pond or other appropriate outfall. 4.2.6 Construction Considerations Unstable subgrade conditions may be encountered during general construction operations, especially if the soils are wetted and/or subjected to repetitive construction traffic. Soils that are pumping or become disturbed are not considered suitable for support of structures and should be removed and replaced with compacted structural fill. Stabilization rock, in combination with geotextiles and separation fabric may be required to stabilize soft pumping soils or provide a stable working platform. The use of light construction equipment, minimize repetitive trafficking and construction during dryer seasons would aid in reducing subgrade disturbance. Terracon should be contacted to visit the site and provide stabilization recommendations if soft, unstable soils are encountered. Construction traffic over the completed subgrade should be avoided to the extent practical. The site should also be graded to prevent ponding of surface water on the prepared subgrades or in excavations. If the subgrade should become frozen, desiccated, saturated, or disturbed, the affected material should be removed and replaced with structural fill or these materials should be scarified, moisture conditioned, and recompacted prior to fill placement or floor slab construction. Moisture conditioning and recompacting clay soils may require extended periods of time to allow the material to dry. It is the responsibility of the contractor to provide safe working conditions in connection with underground excavations. Temporary construction excavations should be properly sloped or Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 7 shored. All excavations should comply with applicable local, state and federal safety regulations, including the current OSHA Excavation and Trench Safety Standards. Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of structural fill, site grading, subgrade preparation and proof rolling, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project. 4.3 Foundations Shallow strip and spread footing foundation systems bearing on undisturbed native soil or on properly placed and compacted structural fill may be considered for support of lightly loaded structures, generally one to two story buildings. Moderate to heavy loaded structures, greater than two stories or structures with parking levels or below grade levels will require alternative foundations support as described in Section 4.3.2 of this report. Design recommendations for shallow foundations below lightly loaded buildings are presented in the following table and paragraphs. 4.3.1 Design Recommendations Description Column Wall Net allowable bearing pressure1 See Exhibit D-1 Minimum dimensions 4 feet 18 inches Minimum embedment below finished grade for frost protection 2 30 inches Approximate total settlement from foundation loads 3 < 1 inch Ultimate coefficient of sliding friction 0.30 (native), 0.45 (structural fill) 1. The recommended net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the footing base elevation. Assumes any unsuitable fill or soft soils, if encountered, will be undercut and replaced with compacted structural fill. Structural fill thickness provided in Exhibit D-1. Based upon a Factor of Safety of 3 and adjusted to limit settlement to 1 inch or less. 2. Embedment depth is for perimeter footings and footings beneath unheated areas. 3. The foundation settlement will depend upon the variations within the subsurface soil profile, the structural loading conditions, the embedment depth of the footings, the thickness of compacted fill, and the quality of the earthwork operations. Net allowable bearing pressures for a range of footing widths and structural fill thicknesses below bottom of footing are provided in Exhibit D-1. Net allowable bearing pressures provided limit estimated total settlements to 1 inch or less, for the structural fill thickness and footing sizes indicated. The allowable foundation bearing pressures apply to dead loads plus design live load conditions. The design bearing pressure may be increased by one-third when considering total Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 8 loads that include wind or seismic conditions. The weight of the foundation concrete below grade may be neglected in dead load computations. 4.3.2 Alternative Foundation Support Moderate to heavily loaded structures will require alternative foundation support systems to increase the allowable bearing capacity and control settlement. Alternate systems include, but are not limited to, rammed aggregate piers, grouted columns placed under footings or deep foundations. Based on previous projects, we anticipate the bearing capacity using rammed aggregate piers would increase to approximately 3,000 to 4,000 psf while maintaining 1 inch or less of settlement. Installers and designers of rammed aggregate piers should be contacted to provide detailed design and feasibility information for this project. Deep foundations, such as driven piles or drilled shafts, may be needed for structures with large loads or that contain parking levels or below grade levels. Recommendations regarding specific support systems can be provided once building layout and foundation loads are known and the finial geotechnical exploration is completed. 4.3.3 Construction Considerations The base of all foundation excavations should be free of water and loose or disturbed soil prior to pouring footings or placing structural fill. Structural fill and concrete should be placed soon after excavating, or structural fill placement, to reduce bearing soil disturbance. If the soils at bearing level become excessively dry, disturbed or saturated, or frozen, the affected soil should be removed. The geotechnical engineer should be retained to observe soil at the bottom of foundation excavations. If unsuitable bearing soils are encountered in footing excavations, the excavation should be extended deeper to suitable soils or until sufficient structural fill/stabilization rock can be placed below the footing. Placement of structural fill or stabilization rock below footings should extend laterally beyond all edges of the footings at least 8 inches per foot of overexcavation depth below footing base elevation. Placement and compaction should be completed in accordance with section 4.2.3. The overexcavation and backfill procedure is described in the following figure. Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 9 4.4 Seismic Considerations Based on the results of our exploration, the subsurface soil profile is best represented by Site Class F according to the 2009 International Building Code (IBC) due to the presence of liquefiable soils. Site class factors may be selected based on a Site Class E as shown in the table below, provided the proposed structures have fundamental periods of vibration less than 0.5 second. The National Seismic Hazard Map database was searched to identify the peak ground acceleration (PGA) and spectral accelerations for 0.2 second (Ss) and 1.0 second (S1) periods for a 2% probability of exceedance (PE) in 50 years at the project site for site class B. These values should be adjusted for site effects using appropriate site class factors from the 2009 IBC. Description Value Site Class 1 F 2, 3 Site Latitude N 40.75109° Site Longitude W 111.90119° So PGA 0.74g Ss Spectral Acceleration for a Short Period 1.72g S1 Spectral Acceleration for a 1-Second Period 0.70g Fa Site Coefficient for a Short Period 0.9 3 Fv Site Coefficient for a 1-Second Period 2.4 3 1 Note: In general accordance with the 2009 International Building Code, Table 1613.5.2. IBC Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2 Note: The 2009 International Building Code (IBC) requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope does not include the required 100 foot soil profile determination. The borings extended to a maximum depth of 76½ feet, and this seismic site class definition considers that similar soil conditions continue below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration. 3 As discussed in this report, the site soils are liquefiable; consequently, the Site Class is F per 2009 IBC, Table 1613.5.2, for any profile containing soils vulnerable to potential failure or collapse under seismic loading such as liquefiable soils. However, Section 20.3.1 of ASCE 7-05 allows site coefficients Fa and Fv to be determined assuming that liquefaction does not occur for structures with fundamental periods of vibration less than 0.5 second. Based on the results of the field exploration, Site Class E may be used to determine the values of Fa and Fv in accordance with Section 1613.5.2 of the 2009 IBC. The site is located in an area mapped having a high liquefaction potential1. Sand interbeds were encountered within the clay soil below the water table in all of the borings. Due to the interbedded nature of the sand and clay soils observed in the 5 foot spaced sampling intervals, it is difficult to determine thickness of the sand interbeds. Using the information available from the borings, we estimate liquefaction induced settlement may be on the order of 2 to 4 inches during the design 1 Liquefaction Special Study Areas, Wasatch Front and Nearby Areas, Utah, 2008, Utah Geological Survey, compiled by G.E. Christenson and L.M. Shaw, Supplement Map to Utah Geological Survey Circular 106 Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 10 earthquake (PGA=0.74g) event. Additional subsurface exploration using Cone Penetration Testing (CPT) would provide a nearly continuous profile of subsurface conditions and could be used to better delineate soil layering and refine liquefaction induced settlement magnitudes and help estimate lateral spread potential at the site. If after additional subsurface exploration, the projected liquefaction induced settlement is still considered to be excessive, consideration should be given to mitigation of liquefaction hazards at the site to achieve an acceptable level of risk. The choice of mitigation methods depends on the extent of liquefaction and the related consequences, as well as cost in light of the acceptable level of risk. Mitigation alternatives typically include soil reinforcement utilizing stone columns or the use of reinforced foundation systems designed to accommodate the occurrence of liquefaction and associated vertical and horizontal deformations. Additional information regarding mitigation alternatives will be provided upon request. 4.5 Floor Slab 4.5.1 Design Recommendations Existing fill materials were encountered at this site to depths of about 2 to 4 feet in our borings. As discussed previously in the earthwork recommendation section, we recommend that existing fill materials below the floor slab areas be removed. Design information for slabs is provided below. Item Description Floor slab support A minimum of 4 inches of crushed gravel underlain by newly placed and compacted structural fill 1 Modulus of subgrade reaction 230 pounds per square inch per inch (psi/in) for point loading conditions2 1. Floor slabs should be structurally independent of any building footings or walls to reduce the possibility of floor slab cracking caused by differential movements between the slab and foundation. We recommend subgrades be maintained in a relatively moist condition until floor slabs are constructed. If the subgrade should become desiccated prior to construction of floor slabs, the affected material should be removed or the materials scarified, moistened, and recompacted. Upon completion of grading operations in the building areas, care should be taken to maintain the recommended subgrade moisture content and density prior to construction of the building floor slabs. 2. Based upon the floor slab being placed on a minimum of 18 inches of structural fill or existing fill meeting structural fill gradation and compaction requirements. Where appropriate, saw-cut control joints should be placed in the slab to help control the location and extent of cracking. For additional recommendations refer to the ACI Design Manual. Joints or any cracks that develop should be sealed with a water-proof, non-extruding compressible compound specifically recommended for heavy duty concrete pavement and wet environments. Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 11 The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer should refer to ACI 302 and/or ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder. 4.5.2 Construction Considerations On most project sites, the site grading is generally accomplished early in the construction phase. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, rainfall, etc. As a result, the floor slab subgrade may not be suitable for placement of crushed gravel and concrete and corrective action will be required. We recommend the area underlying the floor slab be rough graded and then thoroughly proofrolled with a loaded tandem axle dump truck prior to final grading and placement of crushed gravel. Particular attention should be given to high traffic areas that were rutted and disturbed earlier and to areas containing backfilled trenches. Areas where unsuitable conditions are located should be repaired by removing and replacing the affected material with properly compacted structural fill. All floor slab subgrade areas should be moisture conditioned and properly compacted to the recommendations in this report immediately prior to placement of the gravel and concrete. 5.0 GENERAL COMMENTS Terracon should be retained to review the final redevelopment plans so comments can be made regarding interpretation and implementation of our preliminary geotechnical recommendations in the redevelopment plans, and so that final subsurface explorations can be completed and geotechnical recommendations provided for the final design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and preliminary recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah September 6, 2012 Ŷ Terracon Project No. 61125059 12 prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This preliminary report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. APPENDIX A FIELD EXPLORATION Project No. Task No. Scale: Date: 61125059 00 Not to Scale 8/20/2012 Project Mngr: Drawn By: Checked By: Approved By: JWG CRC JWG RLC PROJECT VICINITY MAP Former Fleet Facility Salt Lake City, Utah Salt Lake City Corporation 14850 South Pony Express Rd., Ste 150 N Bluffdale, Utah 84065 FIGURE DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES. A-1 SUBJECT SITE Project No. Task No. Scale: Date: 61125059 00 Not to Scale 8/20/2012 Project Mngr: Drawn By: Checked By: Approved By: JWG CRC JWG RLC BORING LOCATION DIAGRAM Former Fleet Facility Salt Lake City, UT Salt Lake City Corporation 14850 South Pony Express Rd., Ste 150 N Bluffdale, Utah 84065 FIGURE DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES. A-2 B-01 B-02 B-04 B-03 LEGEND: Approximate Boring/CPT Location Consol., TV-1.35 ksf Consol., TV-0.5 ksf ASPHALT: Approximately 6 inches thick FILL: gravel with sand, brown SANDY SILT: stiff, black, trace gravel SILTY CLAY: very soft, gray CLAY: with sand, very soft to stiff, gray 0.5 2 4 9 ML 10 6 1 2 3 4 5 6 7 8 9 1 -- 12 6 0 -- 3 12 18 11 18 12 18 9 18 39 22 SS SS ST SS SS SS ST SS 5022 19 45 112 72 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 1 of 2 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 15 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines DESCRIPTION GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-3 BORING STARTED Southcentral portion of site 8-2-12 LOG OF BORING NO. B-01 Boring Location: JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 UU Triax., PP-2.5 ksf CLAY: with sand, very soft to stiff, gray Boring completed at approximately 41.5 feet below ground surface 41.5 9 10 -- 1 16 18 ST SS 24 104 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 2 of 2 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah OWNER CME-55 WL WL WL 15 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-3 BORING STARTED 8-2-12 LOG OF BORING NO. B-01 JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 33 34 35 36 37 38 39 40 41 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 UU Triax., TV-1.3 ksf Consol., TV-1.1 ksf ASPHALT: Approximately 4 inches thick FILL: gravel with sand, black CLAY: with sand layers, very soft to medium stiff, black and gray 0.33 3 CL 19 15 1 2 3 4 5 6 7 8 7 -- 5 -- 1 0 5 -- 12 16 18 18 12 12 18 24 43 40 SS ST SS ST SS SS SS ST 93 98 34 24 58 43 93 101 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 1 of 2 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 14 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines DESCRIPTION GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-4 BORING STARTED Northeast corner of site 8-2-12 LOG OF BORING NO. B-02 Boring Location: JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 CLAY: with sand layers, very soft to medium stiff, black and gray Boring completed at approximately 41.5 feet below ground surface 41.5 9 10 1 0 18 18 SS SS 47 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 2 of 2 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah OWNER CME-55 WL WL WL 14 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-4 BORING STARTED 8-2-12 LOG OF BORING NO. B-02 JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 33 34 35 36 37 38 39 40 41 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 PP-0.5 ksf, TV-0.8 ksf ASPHALT: Approximately 4 inches thick FILL: gravel with sand, black CLAY: soft, black CLAY: with sand layers, very soft to soft, gray 0.33 3.5 8 1 2 3 4 5 6 7 8 50/5" 3 6 8 3 -- 2 0 8 18 18 18 18 10 18 18 SS SS SS SS SS ST SS SS 7 31 33 35 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 1 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 15 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines DESCRIPTION GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-5 BORING STARTED Center of site 8-3-12 LOG OF BORING NO. B-03 Boring Location: JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 Consol. UU Triax., PP-2 ksf, TV-2ksf CLAY: with sand layers, very soft to soft, gray CLAY: very soft, black 43 64 9 18 9 10 11 12 13 14 3 -- 0 0 0 -- 18 24 18 18 18 15 30 40 SS ST SS SS SS ST 37 33 37 21 97 105 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 2 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 15 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-5 BORING STARTED 8-3-12 LOG OF BORING NO. B-03 JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 SANDY SILTY CLAY: stiff to very stiff, gray Boring completed at approximately 76.5 feet below ground surface 76.5 15 16 17 11 25 26 18 18 18 SS SS SS 6829 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 3 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah OWNER CME-55 WL WL WL 15 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-5 BORING STARTED 8-3-12 LOG OF BORING NO. B-03 JOB # PROJECT 8-2-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 66 67 68 69 70 71 72 73 74 75 76 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 PP-0.5 ksf, TV-0.9 ksf ASPHALT: Approximately 4 inches thick FILL: gravel with silt, sand and debris, brown and black CLAY: medium stiff, black CLAY: with sand layers, very soft to soft, gray 0.33 4 9 24 1 2 3 4 5 6 7 8 19 5 -- 4 -- 0 4 1 18 18 24 18 21 18 18 18 49 SS SS ST SS ST SS SS SS 31 30 37 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 1 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 12 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines DESCRIPTION GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-6 BORING STARTED Northwest corner of site 8-3-12 LOG OF BORING NO. B-04 Boring Location: JOB # PROJECT 8-3-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 PP-0.3 ksf, TV-0.5 ksf UU Triax., PP-1.5 ksf, TV-1.2 ksf CLAY: with sand layers, very soft to soft, gray CLAY: very soft, black SANDY SILTY CLAY: very stiff, black and gray 43 58 9 10 11 12 13 14 0 -- 0 -- 0 17 18 24 18 24 18 18 SS ST SS ST SS SS 66 99 27 34 25 86 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 2 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah Continued Next Page OWNER CME-55 WL WL WL 12 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-6 BORING STARTED 8-3-12 LOG OF BORING NO. B-04 JOB # PROJECT 8-3-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 SANDY SILTY CLAY: very stiff, black and gray SAND: with silty clay, very loose to medium dense - flowing sands Boring completed at approximately 75 feet below ground surface 70 75 615 16 18 3 18 18 25SS SS 27 TESTS OTHER WATER LEVEL OBSERVATIONS, ft CRC APPROVED between soil and rock types: in-situ, the transition may be gradual. Page 3 of 3 Former Fleet Facility Salt Lake City Corporation WD 850 South 300 West Salt Lake City, Utah OWNER CME-55 WL WL WL 12 SITE BORING COMPLETED FOREMAN The stratification lines represent the approximate boundary lines GR A P H I C L O G Auto Hammer, Hollow Stem Auger Exhibit A-6 BORING STARTED 8-3-12 LOG OF BORING NO. B-04 JOB # PROJECT 8-3-12 61125059 RIG RLC US C S S o i l S y m b o l NU M B E R TY P E % P A S S I N G NO . 2 0 0 S I E V E DE P T H , f t . DR Y U N I T WE I G H T , P C F WA T E R CO N T E N T , % RE C O V E R Y , i n . LI Q U I D L I M I T 66 67 68 69 70 71 72 73 74 75 SAMPLES PL A S T I C I T Y IN D E X PE N E T R A T I O N RE S I S T A N C E BL O W S / f t . BO R E H O L E _ 9 9 6 1 1 2 5 0 5 9 . G P J T E R R A C O N . G D T 8 / 2 7 / 1 2 Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah August 27, 2012 Ŷ Terracon Project No. 61125059 Exhibit A-7 Field Exploration Description The boring locations were located in the field by Terracon by referencing an aerial map and estimating distances from existing features. The locations of the borings should be considered accurate only to the degree implied by the means and methods used to define them. The borings were drilled with a truck-mounted CME-75 rotary drill rig using continuous flight hollow-stem augers. Samples of the soil encountered in the borings were obtained using the split-barrel and thin-walled tube sampling procedures. In the split-barrel sampling procedure, the number of blows required to advance a standard 2- inch O.D. split-barrel sampler the last 12 inches of the typical total 18-inch penetration by means of a 140-pound hammer with a free fall of 30 inches, is the standard penetration resistance value (SPT-N). This value is used to estimate the in-situ relative density of cohesionless soils and consistency of cohesive soils. An automatic SPT hammer was used to advance the split-barrel sampler in the borings performed on this site. A significantly greater efficiency is achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. This higher efficiency has an appreciable effect on the SPT-N value. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report. In the thin-walled tube sampling procedure, a thin-walled, seamless steel tube with a sharp cutting edge is pushed hydraulically into the soil to obtain a relatively undisturbed sample. The samples were tagged for identification, sealed to reduce moisture loss, and taken to our laboratory for further examination, testing, and classification. Information provided on the boring logs attached to this report includes soil descriptions, consistency evaluations, boring depths, sampling intervals, and groundwater conditions. The borings were backfilled with auger cuttings and capped with asphalt cold patch prior to the drill crew leaving the site. A field log of each boring was prepared by the field engineer during drilling. These logs included visual classifications of the materials encountered during drilling as well as the field engineer’s interpretation of the subsurface conditions between samples. Final boring logs included with this report represent the engineer's interpretation of the field logs and include modifications based on laboratory observation and tests of the samples. APPENDIX B LABORATORY TESTING Preliminary Geotechnical Engineering Report Former Fleet Facility Ŷ Salt Lake City, Utah August 27, 2012 Ŷ Terracon Project No. 61125059 Exhibit B-1 Laboratory Testing Samples retrieved during the field exploration were taken to the laboratory for further observation by the project geotechnical engineer and were classified in accordance with the Unified Soil Classification System (USCS) described in Appendix A. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Laboratory tests were conducted on selected soil samples and the test results are presented in this appendix. The laboratory test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards. Selected soil samples obtained from the site were tested for the following engineering properties: „ In-situ Water Content „ Minus 200 Sieve Analysis „ Atterberg Limits „ Consolidation „ Unit Weight „ Unconsolidated-Undrained (UU) Triaxial Strength Results of the laboratory tests are summarized on the boring logs in Appendix A, reported in Appendix B, and in this report. Before Consolidation Sample Diameter (in):2.49 Moist Unit Weight (pcf):134 Sample Height (in):1.005 Moisture Content (%):19 Sample Volume (cf):0.0028 Dry Unit Weight (pcf):112 After Consolidation Sample Diameter (in):2.49 Moist Unit Weight (pcf):142 Sample Height (in):0.93456 Moisture Content (%):17 Sample Volume (cf):0.0026 Dry Unit Weight (pcf):121 Liquid Limit:22 Percent Fines:-- Plasticity Index:6 Classification:Silty Clay (CL-ML) Project Name: Project No.: Location: Sample: Consolidation Test Data (ASTM D 2435-04 ) SLC Former Fleet Lot 61125059 B-1 @ 7.5' Salt Lake City, UT 0.0 2.0 4.0 6.0 8.0 10.0 12.0 0.1 1 10 100 VE R T I C A L S T R A I N , % VERTICAL STRESS, ksf Exhibit B-2 Before Consolidation Sample Diameter (in):2.50 Moist Unit Weight (pcf):104 Sample Height (in):1.013 Moisture Content (%):45 Sample Volume (cf):0.0029 Dry Unit Weight (pcf):72 After Consolidation Sample Diameter (in):2.50 Moist Unit Weight (pcf):127 Sample Height (in):0.7857 Moisture Content (%):37 Sample Volume (cf):0.0022 Dry Unit Weight (pcf):93 Liquid Limit:--Percent Fines:-- Plasticity Index:--Classification:Clay Project Name: Project No.: Location: Sample: Consolidation Test Data (ASTM D 2435-04 ) SLC Former Fleet Lot 61125059 B-1 @ 25' Salt Lake City, UT 0.0 5.0 10.0 15.0 20.0 25.0 30.0 0.1 1 10 100 VE R T I C A L S T R A I N , % VERTICAL STRESS, ksf Exhibit B-3 Before Consolidation Sample Diameter (in):2.50 Moist Unit Weight (pcf):125 Sample Height (in):1 Moisture Content (%):24 Sample Volume (cf):0.0028 Dry Unit Weight (pcf):101 After Consolidation Sample Diameter (in):2.50 Moist Unit Weight (pcf): Sample Height (in):0.95958 Moisture Content (%): Sample Volume (cf):0.0027 Dry Unit Weight (pcf): Liquid Limit:--Percent Fines:-- Plasticity Index:--Classification:Clay Project Name: Project No.: Location: Sample: Consolidation Test Data (ASTM D 2435-04 ) SLC Former Fleet Lot 61125059 B-2 @ 10' Salt Lake City, UT 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0.1 1 10 100 VE R T I C A L S T R A I N , % VERTICAL STRESS, ksf Exhibit B-4 Before Consolidation Sample Diameter (in):2.46 Moist Unit Weight (pcf):129 Sample Height (in):1.002 Moisture Content (%):33 Sample Volume (cf):0.0028 Dry Unit Weight (pcf):97 After Consolidation Sample Diameter (in):2.46 Moist Unit Weight (pcf):135 Sample Height (in):0.8766 Moisture Content (%):22 Sample Volume (cf):0.0024 Dry Unit Weight (pcf):111 Liquid Limit:30 Percent Fines:-- Plasticity Index:9 Classification:Lean Clay (CL) Project Name: Project No.: Location: Sample: Consolidation Test Data (ASTM D 2435-04 ) SLC Former Fleet Lot 61125059 B-3 @ 40' Salt Lake City, UT 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 0.1 1 10 100 VE R T I C A L S T R A I N , % VERTICAL STRESS, ksf Exhibit B-5 Axial Deviator Shear Strain Stress Stress (%)(psf)(psf) 0.00 0.0 0.0 0.00 0.0 0.0 0.04 46.3 23.2 0.08 69.8 34.9 0.16 111.2 55.6 0.25 150.6 75.3 0.35 191.6 95.8 0.50 250.4 125.2 0.60 284.0 142.0 0.69 321.3 160.7 0.80 360.0 180.0 0.90 400.7 200.3 1.00 443.2 221.6 1.99 909.1 454.5 3.01 1323.8 661.9 4.02 1589.1 794.6 5.03 1728.0 864.0 6.05 1797.8 898.9 7.06 1860.6 930.3 8.07 1900.1 950.1 9.08 1906.4 953.2 10.09 1951.5 975.8 11.09 2015.2 1007.6 12.11 2082.7 1041.4 13.11 2172.5 1086.3 14.13 2287.8 1143.9 15.13 2408.1 1204.1 16.14 2560.2 1280.1 17.15 2724.3 1362.2 18.16 2902.1 1451.1 19.16 3108.9 1554.5 20.00 3282.4 1641.2 Sample Diameter (in):2.80 Moist Unit Weight (pcf):128 Sample Height (in):6.6 Moisture Content (%):23.5 Sample Volume (cf):0.0235 Dry Unit Weight (pcf):104 Confining Stress (psf):600.94 Strain at Falure (%)20 Strain Rate (%/min):1.00 Shear Stress at Falure (psf)1641 Strain Rate (in/min):0.0666 Project Name: Project No.: Location: Sample: Sample Description:clay Unconsolidated-Undrained Triaxial Compression Test (ASTM D2850) Former Fleet Lot 61125059 Salt Lake City, UT B-1 @ 35' 3282.4 0 500 1000 1500 2000 2500 3000 3500 0 5 10 15 20 De v i a t o r S t r e s s , p s f Strain, % Exhibit B-6 Axial Deviator Shear Strain Stress Stress (%)(psf)(psf) 0.00 0.0 0.0 0.00 0.0 0.0 0.03 94.6 47.3 0.08 158.6 79.3 0.16 262.7 131.4 0.25 364.2 182.1 0.33 456.3 228.2 0.50 589.8 294.9 0.60 661.4 330.7 0.70 731.0 365.5 0.79 796.8 398.4 0.90 859.1 429.5 1.01 924.5 462.3 2.02 1401.8 700.9 3.03 1801.4 900.7 4.03 2164.3 1082.2 5.04 2446.1 1223.1 6.04 2612.5 1306.3 7.05 2767.7 1383.9 8.07 2908.3 1454.2 9.08 2952.2 1476.1 10.09 2992.5 1496.3 11.09 3046.3 1523.2 12.10 3067.1 1533.6 13.11 3064.2 1532.1 14.12 3098.6 1549.3 15.13 3107.7 1553.9 16.15 3073.7 1536.9 17.15 3087.5 1543.8 18.16 3124.1 1562.1 19.17 3117.1 1558.6 20.00 3101.3 1550.7 Sample Diameter (in):2.80 Moist Unit Weight (pcf):124 Sample Height (in):6.1 Moisture Content (%):34 Sample Volume (cf):0.0217 Dry Unit Weight (pcf):93 Confining Stress (psf):592.53 Strain at Falure (%)18 Strain Rate (%/min):1.00 Shear Stress at Falure (psf)1562 Strain Rate (in/min):0.0612 Project Name: Project No.: Location: Sample: Sample Description:Lean Clay (CL) Unconsolidated-Undrained Triaxial Compression Test (ASTM D2850) Former Fleet Lot 61125059 Salt Lake City, UT B-2 @ 5' 3124.1 0 500 1000 1500 2000 2500 3000 3500 0 5 10 15 20 De v i a t o r S t r e s s , p s f Strain, % Exhibit B-7 Axial Deviator Shear Strain Stress Stress (%)(psf)(psf) 0.00 0.0 0.0 0.00 0.0 0.0 0.03 0.0 0.0 0.08 0.0 0.0 0.16 57.2 28.6 0.25 213.1 106.5 0.33 334.1 167.1 0.49 515.9 257.9 0.58 619.6 309.8 0.69 734.0 367.0 0.79 844.8 422.4 0.89 949.6 474.8 0.99 1054.1 527.1 1.99 1898.1 949.1 3.00 2539.6 1269.8 4.00 2986.5 1493.3 5.02 3333.1 1666.6 6.03 3589.0 1794.5 7.05 3792.5 1896.3 8.06 4013.7 2006.9 9.08 4164.8 2082.4 10.09 4273.5 2136.8 11.10 4410.6 2205.3 12.10 4510.6 2255.3 13.13 4568.2 2284.1 14.13 4650.4 2325.2 15.14 4724.4 2362.2 16.16 4735.7 2367.9 17.17 4779.4 2389.7 18.17 4831.5 2415.8 19.16 4846.8 2423.4 20.00 4879.6 2439.8 Sample Diameter (in):2.76 Moist Unit Weight (pcf):127 Sample Height (in):6.3 Moisture Content (%):21 Sample Volume (cf):0.0218 Dry Unit Weight (pcf):105 Confining Stress (psf):597.17 Strain at Falure (%)20 Strain Rate (%/min):1.00 Shear Stress at Falure (psf)2440 Strain Rate (in/min):0.0635 Project Name: Project No.: Location: Sample: Sample Description:Lean Clay (CL) Unconsolidated-Undrained Triaxial Compression Test (ASTM D2850) Former Fleet Lot 61125059 Salt Lake City, UT B-3 @ 60' 4879.6 0 1000 2000 3000 4000 5000 6000 0 5 10 15 20 De v i a t o r S t r e s s , p s f Strain, % Exhibit B-8 Axial Deviator Shear Strain Stress Stress (%)(psf)(psf) 0.00 0.0 0.0 0.00 1.1 0.5 0.07 246.0 123.0 0.16 329.7 164.8 0.31 451.1 225.5 0.50 547.0 273.5 0.71 633.4 316.7 1.02 765.5 382.7 1.52 981.7 490.8 1.81 1109.8 554.9 2.02 1190.4 595.2 4.03 1712.5 856.3 6.04 1995.5 997.8 8.07 2071.3 1035.7 10.09 2083.5 1041.8 12.10 2066.9 1033.5 14.11 1924.3 962.2 16.14 1811.1 905.6 18.15 1689.3 844.7 20.01 1674.9 837.5 Sample Diameter (in):2.84 Moist Unit Weight (pcf):115 Sample Height (in):6.116667 Moisture Content (%):34 Sample Volume (cf):0.0224 Dry Unit Weight (pcf):86 Confining Stress (psf):604.21 Strain at Falure (%)10 Strain Rate (%/min):2.00 Shear Stress at Falure (psf)1042 Strain Rate (in/min):0.1234 Project Name: Project No.: Location: Sample: Sample Description:clay Unconsolidated-Undrained Triaxial Compression Test (ASTM D2850) Former Fleet Lot 61125059 Salt Lake City, UT B-4 @ 50' 2083.5 0 500 1000 1500 2000 2500 0 5 10 15 20 De v i a t o r S t r e s s , p s f Strain, % Exhibit B-9 APPENDIX C SUPPORTING DOCUMENTS GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1-3/8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube - 2" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger DB: Diamond Bit Coring - 4", N, B RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling N/E: Not Encountered WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS Unconfined Compressive Strength, Qu, psf Standard Penetration or N-value (SS) Blows/Ft. Consistency Standard Penetration or N-value (SS) Blows/Ft. Relative Density < 500 0 - 1 Very Soft 0 – 3 Very Loose 500 – 1,000 2 - 4 Soft 4 – 9 Loose 1,000 – 2,000 2,000 4 - 8 Medium Stiff 10 – 29 Medium Dense 2,000 – 4,000 4,000 8 - 15 Stiff 30 – 49 Dense 4,000 – 8,000 15 - 30 Very Stiff > 50 Very Dense 8,000+ > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term(s) of other constituents Percent of Dry Weight Major Component of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) RELATIVE PROPORTIONS OF FINES Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) Descriptive Term(s) of other constituents Percent of Dry Weight PLASTICITY DESCRIPTION Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 > 30 Exhibit A-6 UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Cu ≥ 4 and 1 ≤ Cc ≤ 3E GW Well-graded gravelF Clean Gravels Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Cu ≥ 6 and 1 ≤ Cc ≤ 3E SW Well-graded sandI Clean Sands Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines Classify as CL or CH SC Clayey sandG,H,I PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Silts and Clays Liquid limit less than 50 inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,P organic Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = 6010 2 30 DxD )(D F If soil contains ≥ 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ≥ 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ≥ 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains ≥ 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ≥ 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. APPENDIX D BEARING PRESSURE CHARTS Project No. Task No. Scale: Date: 61125059 0 Not to Scale 8/27/2012 Project Mngr: Drawn By: Checked By: Approved By: JWG CRC JWG RLC NET ALLOWABLE BEARING PRESSURES FORMER FLEET FACILITY 850 South 300 West, Salt Lake City, Utah Salt Lake City Corporation 14850 S Pony Express Rd., Ste 150N Bluffdale, Utah 84065 EXHIBIT D-1 0 500 1,000 1,500 2,000 2,500 3,000 3,500 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Ne t A l l o w a b l e B e a r i n g P r e s s u r e - ps f Str. Fill Thickness Below Footing - ft Strip Footing Footing Width = 1.5 feet Footing Width = 2 feet Footing Width = 2.5 feet Footing Width = 3 feet Footing Width = 4 feet 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Ne t A l l o w a b l e B e a r i n g P r e s s u r e - ps f Str. Fill Thickness Below Footing - ft Column Footing Footing Size = 4 x 4 feet Footing Size = 5 x 5 feet Footing Size = 6 x 6 feet Footing Size = 7 x 7 feet Footing Size = 10 x 10 feet Footing Size = 12 x 12 feet