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HomeMy WebLinkAboutMAVERIK CONVENIENCE STORE & FUEL SALES - PDP - PDP150028 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTREPORT GEOTECHNICAL STUDY PROPOSED MAVERIK COUNTRY STORE APPROXIMATELY 4333 EAST MULBERRY STREET FORT COLLINS, COLORADO Submitted To: Maverik, Inc. Attention: Mr. Nissen Liddiard 880 West Center Street North Salt Lake, Utah Submitted By: GSH Geotechnical, Inc. July 23, 2015 Job No. 0148-080-15 GSH Geotechnical, Inc. GSH Geotechnical, Inc. 473 West 4800 South 1596 West 2650 South, Suite 107 Salt Lake City, Utah 84123 Ogden, Utah 84401 Tel: 801.685.9190 Tel: 801.393.2012 www.gshgeo.com July 23, 2015 Job No. 0148-080-15 Ms. Nissen Liddiard Maverik, Inc. 880 West Center Street North Salt Lake, Utah 84054 Ms. Liddiard: Re: Report Geotechnical Study Proposed Maverik Country Store Approximately 4333 East Mulberry Street Fort Collins, Colorado (40.580123º North, -104.997878º West) 1. INTRODUCTION 1.1 GENERAL This report presents the results of our geotechnical study performed at the site of the proposed Maverik Country Store located at approximately 4333 East Mulberry Street in Fort Collins, Colorado. The general location of the site with respect to major roadways, as of 2015, is presented on Figure 1, Vicinity Map. A more detailed layout of the site showing proposed facilities and roadways is presented on Figure 2, Site Plan. The locations of the borings drilled in conjunction with this study are also presented on Figure 2. 1.2 OBJECTIVES AND SCOPE The objectives and scope of the study were planned in discussions between Ms. Nissen Liddiard of Maverik, Inc. and Mr. Alan Spilker of GSH Geotechnical, Inc. (GSH). In general, the objectives of this study were to: 1. Define and evaluate the subsurface soil and groundwater conditions across the site. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 2 2. Provide appropriate foundation, earthwork, and pavement recommendations, and geoseismic information to be utilized in the design and construction of the proposed facilities. In accomplishing these objectives, our scope has included the following: 1. A field program consisting of the drilling, logging, and sampling of 6 exploration borings. 2. A laboratory testing program. 3. An office program consisting of the correlation of available data, engineering analyses, and the preparation of this summary report. 1.3 AUTHORIZATION Authorization was provided by returning a signed copy of our Professional Services Agreement No. 15-0641 dated June 18, 2015. 1.4 PROFESSIONAL STATEMENTS Supporting data which form the basis of our recommendations are presented in subsequent sections of this report. Recommendations presented herein are governed by the physical properties of the soils encountered in the exploration borings, projected groundwater conditions, and the layout and design data discussed in Section 2, Proposed Construction. If subsurface conditions other than those described in this report are encountered and/or if design and layout changes are implemented, GSH must be informed so that our recommendations can be reviewed and amended, if necessary. Our professional services have been performed, our findings developed, and our recommendations prepared in accordance with generally accepted engineering principles and practices in this area at this time. 2. PROPOSED CONSTRUCTION The proposed Maverik Country Store will include a convenience store, 5 fueling islands with an overhead continuous canopy, 4 buried fuel tanks, and surrounding at-grade pavements. An existing America’s Best Value Inn and Suites is located on the site property. The proposed Maverik Country Store will be located where an existing restaurant (to be demolished) is currently located at the east end of the America’s Best Value Inn & Suites property. The store structure will have a footprint of 5,046 square feet, will be one-extended level in height with slab on grade floors, and will be of light steel/wood-frame and masonry/stucco construction. Structural loads will be transmitted down through bearing walls and isolated columns to Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 3 supporting footings. We estimate that maximum wall and column loads will be on the order of 2 to 3 kips per lineal foot and 30 to 50 kips, respectively. The fueling islands as shown on Figure 2 will be constructed to the east of the store and within present asphalt paved parking associated with the existing hotel. The islands will be covered with a continuous overhead canopy with a plan area of 137 feet long by 52 feet wide. The canopy will be supported by a steel frame and column structure extending to concrete spread foundations. It is projected that the maximum downward column loads will be on the order of 15 to 30 kips. In addition, uplift and lateral loads will be imposed upon these foundations. Fuel storage tanks will be located east of the fueling islands within a present undeveloped area. It is projected that 4 tanks will be installed with the tank bottoms extending approximately 14 feet below existing site grade. The areas around the facilities will be paved. Some existing asphalt pavements may likely remain in use. Concrete pavement slabs will be installed in front of the proposed store structure, over the underground storage tanks, and within the canopied fuel island areas. In other areas, asphalt concrete sections will be used. Traffic in the parking areas adjacent to the convenience store will consist of a light to moderate volume of automobiles and light trucks. Traffic over the remaining pavements will consist of a moderate volume of automobiles and light trucks, a light volume of medium-weight trucks, and occasional heavy-weight gasoline supply trucks. Site development will require demolition of the existing building and pavements followed by some earthwork in the form of cutting and filling for site drainage. At this time, we project that maximum site grading cuts and fills, excluding the fuel storage tanks, will be up to about 2 to 3 feet. 3. SITE INVESTIGATIONS 3.1 FIELD PROGRAM In order to define and evaluate the subsurface soil and groundwater conditions across the site, 6 borings were drilled to depths ranging from 16.5 to 31.5 feet with a truck-mounted drill rig equipped with hollow-stem augers. Locations of the borings are presented on Figure 2, Site Plan. The field portion of our study was under the direct control and continual supervision of an experienced member of our geotechnical staff. During the course of the drilling operations, a continuous log of the subsurface conditions encountered was maintained. In addition, samples of the typical soils encountered were obtained for subsequent laboratory testing and examination. The soils were classified in the field based upon visual and textural examination. These classifications were supplemented by subsequent inspection and testing in our laboratory. Detailed graphical representation of the subsurface conditions encountered is presented on Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 4 Figures 3A through 3F, Boring Logs. Soils were classified in accordance with the nomenclature described on Figure 4, Key to Boring Log (USCS). A 3.25-inch outside diameter, 2.42-inch inside diameter drive sampler (Dames & Moore) and a 2.0-inch outside diameter, 1.38-inch inside diameter drive sampler (SPT) were utilized in the subsurface sampling at the site. The blow counts recorded on the boring logs were those required to drive the sampler 12 inches with a 140-pound hammer dropping 30 inches. Following completion of drilling operations, a 1.25-inch diameter slotted PVC pipe was installed in Boring B-2 in order to provide a means of monitoring the groundwater fluctuations. The borings were backfilled with auger cuttings. 3.2 LABORATORY TESTING 3.2.1 General In order to provide data necessary for our engineering analyses, a laboratory testing program was performed. This program included partial and full gradation, Atterberg limits, and chemical tests. The following paragraphs describe the tests and summarize the test data. 3.2.2 Partial Gradation Tests To aid in classifying the granular soils, partial gradation tests were performed. Results of the tests are tabulated below: Boring No. Depth (feet) Percent Passing No. 200 Sieve Moisture Content Percent Soil Classification B-2 20.0 10.1 11.9 SP-SM B-2 30.0 21.9 20.5 SM B-3 7.0 18.0 7.2 SM B-3 15.0 4.4 7.2 SP B-4 7.0 23.9 14.6 SM B-4 10.0 41.9 17.4 SC-SM Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 5 3.2.3 Full Gradation Tests To aid in classifying soils, full gradation tests were performed. Results of the tests are tabulated below: Boring No Depth (feet) Soil Type Percent Passing Sieve 1/2 " 3/8" No. 4 No. 10 No. 20 No. 40 No. 100 No. 200 B-1 15.0 SP-SM 100 95 79 54 38 30 18 9 B-2 15.0 SP-SM 100 94 75 47 33 25 16 8 3.2.4 Atterberg Limit Tests To aid in classifying the soils, an Atterberg limit test was performed on a sample of the fine- grained cohesive soils. Results of the test are tabulated below: Boring No. Depth (feet) Liquid Limit (percent) Plastic Limit (percent) Plasticity Index (percent) Soil Classification B-1 10 38 16 22 CL 3.2.5 Chemical Tests To determine if the site soils will react detrimentally with concrete, chemical tests were performed on a representative sample of the soils encountered at the site. The results of the chemical tests are tabulated below: Boring No. Depth (feet) pH Total Water Soluble Sulfate (mg/kg-dry) Soil Classification B-2 7.0 8.05 167 SC-Fill 4. SITE CONDITIONS Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 6 to fair condition. Further east, where the planned buried fuel tanks will be located, is a vacant/undeveloped area with the frontage roadway beyond. The frontage road surrounds the site property along the east and curves around along the south heading west. The existing hotel structures are located to the south and west of the planned store structure. The overall property topography is relatively flat and is lower that the surrounding frontage roadway to the east and grades higher than the frontage roadway along the south. 4.2 SUBSURFACE SOIL Surficial fills were encountered at the surface within each boring extending to depths ranging from about 6.0 to 9.0 feet below the surface. The fills encountered at the boring locations consisted primarily of silty/sandy/gravelly clay and clayey sand which varied between medium stiff to stiff/ very loose to loose. Based on the variability in density of the surface fills, it is anticipated that these fills were not adequately compacted or engineered for new building construction and, therefore, must be considered non-engineered. Below the fills, natural soils were encountered comprised primarily of sand with varying silt/clay content extending to the full depths penetrated of about 16.5 to 31.5 feet. These natural sands were loose to medium dense, moist to saturated, and brown in color. Occasional layer of silty clay up to 4 feet thick were encountered within the primarily natural sand sequence which were medium stiff to stiff, moist to saturated, and brown in color. Groundwater was observed within the borings at the time of drilling at depths below the ground surface of about 10.0 to 12.0 feet. On June 29, 2015, three days following drilling, static groundwater was measured in the perforated pipe installed in Boring B-2 at a depth of about 9.1 feet below the ground surface. For a more detailed description of subsurface conditions, please refer to Figures 3A through 3F, Boring Logs. The lines designating the interface between soil types on the boring logs generally represent approximate boundaries. In-situ, the transition between soil types may be gradual. 5. DISCUSSIONS AND RECOMMENDATIONS 5.1 SUMMARY OF FINDINGS The proposed structures may be supported upon conventional spread and continuous wall foundations supported upon suitable natural soils and/or structural fill extending to suitable natural soils. The most significant geotechnical aspects of the site are: 1. The existing fills (considered to be non-engineered with respect to the proposed structures and foundations), which at the boring locations extended to depths of about 6.0 to 9.0 feet below the surface, and Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 7 2. The moderate depth to groundwater. The surface fills are primarily fine grained in nature and vary in stiffness/density. Unless documentation can be provided indicating that these fills are clean of debris and have been compacted to the requirements for structural fill as stated within this report, they must be considered non-engineered. All non-engineered fills must be removed below the proposed store building and all foundations. The in-situ, non-engineered fills may remain below pavements if free of any deleterious materials, and are properly prepared, as discussed later in this report. It must be noted that from a handling and compaction standpoint, soils containing high amounts of fines (silts and clays) are inherently more difficult to rework and are very sensitive to changes in moisture content, requiring very close moisture control during placement and compaction. This will be very difficult, if not impossible, during wet and cold periods of the year. Static groundwater was measured at a depth of 9.1 feet below the surface at Boring B-2. We anticipate that the fuel tank excavations will extend as much as 14 feet below the finish grade, which may be affected by groundwater. Dewatering may be required. Detailed discussions pertaining to earthwork, foundations, pavements, and the geoseismic setting of the site are presented in the following sections. 5.2 EARTHWORK 5.2.1 Site Preparation Initial site preparation will consist of the demolition and removal of the existing restaurant structure and all associated debris, pavements, deleterious materials, and non-engineered fills extending out a minimum 3 feet beyond the perimeter of the proposed store and from below all exterior foundations (canopy footings). Existing utilities will need to be removed/abandoned or relocated to accommodate new construction. Removal of existing pavement, surface vegetation, topsoil, and any deleterious materials will be required in the areas of the fuel islands, pavements and underground fuel tanks. In situ, non- engineered fills may remain below pavements if free of debris and deleterious materials, and if properly prepared. Proper preparation below pavements will consist of the scarification of the upper 12 inches below asphaltic concrete (flexible pavement), and 24 inches below slabs/rigid pavement followed by moisture preparation and re-compaction to the requirements of structural fill. The thicker sequence of prepared soils below slabs/rigid pavements would require the temporary removal of 12 inches of fill, scarifying, moisture conditioning, and recompacting the underlying 12 inches and backfilling with compacted suitable fills. Even with proper preparation, pavements established overlying non-engineered fills may encounter some long-term movements unless the non-engineered fills are completely removed. Installing reinforcement in flatwork over fills may help reduce potential displacement cracking. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 8 It must be noted that from a handling and compaction standpoint, onsite soils containing high amounts of fines (silts and clays) are inherently more difficult to rework and are very sensitive to changes in moisture content requiring very close moisture control during placement and compaction. This will be very difficult, if not impossible, during wet and cold periods of the year. As an alternative, the fills may be removed and replaced with imported granular structural fill over unfrozen, proofrolled subgrade. Subsequent to stripping and prior to the placement of structural site grading fill, pavements, and slabs on grade, the prepared subgrade must be proofrolled by passing moderate-weight rubber tire-mounted construction equipment over the surface at least twice. If excessively soft or loose soils are encountered, they must be removed to a maximum depth of 2 feet and replaced with structural fill. Beneath footings, all loose and disturbed soils must be totally removed. Fill soils must be handled as described above. A representative of GSH must verify that suitable natural soils and/or proper preparation of existing fills have been encountered/met prior to placing site grading fills, footings, slabs, and pavements. 5.2.2 Temporary Dewatering Static groundwater was measured in boring B-2 at a depth of 9.1 feet below the ground surface and within a natural sand sequence. Planned underground fuel tanks could extend to a depth of roughly 14 feet below the surface. The soils encountered between about 9.0 and 14.0 feet consisted of sands with varying fine, which when saturated could flow into the excavation. Therefore, it may be prudent to begin dewatering by inserting multiple well points around the planned fuel tank excavation several days prior to beginning the mass excavation. Additionally, once the mass excavation is complete, a perimeter trench may be dug 1 to 2 feet deeper around the base of the excavation, allowing groundwater to drain to a low point and be pumped out. Excavation side slopes flatter than one horizontal to one vertical (1:H1V) may also be required. 5.2.3 Temporary Excavations Temporary construction excavations in cohesive soil, not exceeding 4 feet in depth and above or below the groundwater table, may be constructed with near-vertical sideslopes. Temporary excavations up to 8 feet deep in fine-grained cohesive soils, above or below the water table, may be constructed with sideslopes no steeper than one-half horizontal to one vertical (0.5H:1V). For granular (cohesionless) soils, construction excavations above the water table, not exceeding 4 feet, should be no steeper than one-half horizontal to one vertical (0.5H:1.0V). For excavations up to 8 feet in granular soils and above the water table, the slopes should be no steeper than one horizontal to one vertical (1.0H:1.0V). Excavations encountering clean or saturated cohesionless soils will be very difficult and will require very flat sideslopes and/or shoring, bracing, dewatering. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 9 Deeper temporary tank excavations, up to approximately 14 feet, will be within saturated soils and in conjunction with dewatering, must be constructed with sideslopes no steeper than one horizontal to one vertical (1H:1V) above the water table. Additionally, excavations encountering saturated cohesionless soils may require flatter sideslopes and/or shoring and bracing. All excavations must be inspected periodically by qualified personnel. If any signs of instability or excessive sloughing are noted, immediate remedial action must be initiated. 5.2.4 Structural Fill Structural fill is defined as all fill which will ultimately be subjected to structural loadings, such as imposed by footings, floor slabs, pavements, etc. Structural fill will be required as site grading fill and as backfill over foundations, utilities, and the underground fuel storage tanks. Generally, fuel storage tank contractors have specific backfill material and compaction requirements. All structural fill must be free of sod, rubbish, topsoil, frozen soil, and other deleterious materials. The maximum particle size within structural site grading fill should generally not exceed 4 inches; although, occasional particles up to 6 to 8 inches may be incorporated provided that they do not result in “honeycombing” or preclude the obtainment of the desired degree of compaction. In confined areas, such as footing and utility excavations, the maximum particle size should generally be restricted to 2 inches. On-site soils may be re-utilized as structural site grading fill if they do not contain deleterious material and meet the requirements of structural fill. As mentioned previously, fine-grained soils will require very close moisture control and may be very difficult, if not impossible, to properly place and compact during wet and cold periods of the year. Only granular soils are recommended in confined areas such as utility trenches, below footings, etc. Generally, we recommend that all imported granular structural fill consist of a well-graded mixture of sands and gravels with no more than 20 percent fines (material passing the No. 200 sieve) and no more than 30 percent retained on the three-quarter-inch sieve. To stabilize soft subgrade conditions (if encountered) or where structural fill is required to be placed closer than 1.0 foot above the water table at the time of construction, a mixture of coarse gravels and cobbles and/or 1.5- to 2.0-inch gravel (stabilizing fill) should be utilized. It may also help to utilize a stabilization fabric, such as Mirafi 600X or equivalent, placed on the native ground if 1.5- to 2.0-inch gravel is used as stabilizing fill. Non-structural site grading fill is defined as all fill material not designated as structural fill and may consist of any cohesive or granular soils not containing excessive amounts of degradable material. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 10 5.2.5 Fill Placement and Compaction All structural fill shall be placed in lifts not exceeding 8 inches in loose thickness. Structural fills shall be compacted in accordance with the percent of the maximum dry density as determined by the ASTM 1 D-1557(AASHTO 2 T-180) compaction criteria in accordance with the table below: Location Total Fill Thickness (feet) Minimum Percentage of Maximum Dry Density Beneath an area extending at least 4 feet beyond the perimeter of the structure 0 to 10 95 Site grading fills outside area defined above 0 to 5 90 Site grading fills outside area defined above 5 to 10 95 Utility trenches within structural areas -- 96 Road base - 96 Structural fills greater than 10 feet thick, excluding fuel storage tank areas, are not anticipated at the site. It is anticipated that the fuel storage tank contractors will specify backfill material and compaction requirements for the tanks. Subsequent to stripping and prior to the placement of structural site grading fill, the subgrade shall be prepared as discussed in Section 5.2.1, Site Preparation, of this report. In confined areas, subgrade preparation should consist of the removal of all loose or disturbed soils. Coarse gravel and cobble mixtures (stabilizing fill), if utilized, shall be end-dumped, spread to a maximum loose lift thickness of 15 inches, and compacted by dropping a backhoe bucket onto the surface continuously at least twice. As an alternative, the fill may be compacted by passing moderately heavy construction equipment or large self-propelled compaction equipment at least twice. Subsequent fill material placed over the coarse gravels and cobbles shall be adequately compacted so that the “fines” are “worked into” the voids in the underlying coarser gravels and cobbles. Non-structural fill may be placed in lifts not exceeding 12 inches in loose thickness and compacted by passing construction, spreading, or hauling equipment over the surface at least twice. 1 American Society for Testing and Materials 2 American Association of State Highway and Transportation Officials Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 11 5.2.6 Utility Trenches All utility trench backfill material below structurally loaded facilities (flatwork, floor slabs, roads, etc.) shall be placed at the same density requirements established for structural fill. If the surface of the backfill becomes disturbed during the course of construction, the backfill shall be proofrolled and/or properly compacted prior to the construction of any exterior flatwork over a backfilled trench. Proofrolling may be performed by passing moderately loaded rubber tire- mounted construction equipment uniformly over the surface at least twice. If excessively loose or soft areas are encountered during proofrolling, they shall be removed to a maximum depth of 2 feet below design finish grade and replaced with structural fill. Many utility companies and City-County governments are now requiring that Type A-1a or A-1b (AASHTO Designation – basically granular soils with limited fines) soils be used as backfill over utilities. These organizations are also requiring that in public roadways, the backfill over major utilities be compacted over the full depth of fill to at least 96 percent of the maximum dry density as determined by the AASHTO T-180 (ASTM D-1557) method of compaction. We recommend that as the major utilities continue onto the site that these compaction specifications are followed. Fine-grained soil, such as silts and clays, are not recommended for utility trench backfill in structural areas. 5.3 SPREAD AND CONTINUOUS WALL FOUNDATIONS 5.3.1 Design Data The results of our analyses indicate that the proposed structures may be supported upon conventional spread and continuous wall foundations established upon suitable natural soils and/or granular structural fill extending to suitable natural soils. For design, the following parameters are provided: Minimum Recommended Depth of Embedment for Frost Protection - 30 inches Minimum Recommended Depth of Embedment for Non-frost Conditions - 15 inches Recommended Minimum Width for Continuous Wall Footings - 18 inches Minimum Recommended Width for Isolated Spread Footings - 24 inches Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 12 Recommended Net Bearing Pressure for Real Load Conditions For footings on suitable natural soils - 2,000 pounds per square foot For footings established on a minimum 18 inches of natural granular soils or granular structural fill extending to suitable natural soils - 2,500 pounds per square foot Bearing Pressure Increase for Seismic Loading - 30 percent The term “net bearing pressure” refers to the pressure imposed by the portion of the structure located above lowest adjacent final grade. Therefore, the weight of the footing and backfill to lowest adjacent final grade need not be considered. Real loads are defined as the total of all dead plus frequently applied live loads. Total load includes all dead and live loads, including seismic and wind. 5.3.2 Installation Under no circumstances shall the footings be installed upon non-engineered fills, loose or disturbed soils, topsoil, sod, rubbish, construction debris, or other deleterious materials. If unsuitable soils are encountered, they must be removed and replaced with compacted granular fill. If granular soils become loose or disturbed, they must be recompacted prior to pouring the concrete. The width of structural fill, where placed below footings, should extend laterally at least 6 inches beyond the edges of the footings in all directions for each foot of fill thickness beneath the footings. For example, if the width of the footing is 2 feet and the thickness of the structural fill beneath the footing is 2 feet, the width of the structural fill at the base of the footing excavation would be a total of 4 feet, centered below the footing. 5.3.3 Settlements Settlements of foundations designed and installed in accordance with the above recommendations and supporting anticipated loads discussed in section 2, Proposed Construction, should not exceed one inch. 5.3.4 Uplift Loads It is anticipated the canopy will be “tied” to the soils with anchors. If the canopy is supported upon conventional spread foundations, uplift loads may be resisted by the weight of the foundation and the backfill within the limits defined by an imaginary line extending outward Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 13 from the outside top edge of the footing 10 degrees from vertical up to finish grade. A unit weight of compacted backfill over the footings of 120 pounds per square foot may be used. 5.4 LATERAL RESISTANCE Lateral loads imposed upon foundations due to wind or seismic forces may be resisted by the development of passive earth pressures and friction between the base of the footings and the supporting soils. In determining frictional resistance, a coefficient of 0.35 should be utilized. Passive resistance provided by properly placed and compacted granular structural fill above the water table may be considered equivalent to a fluid with a density of 300 pounds per cubic foot. A combination of passive earth resistance and friction may be utilized provided that the friction component of the total is divided by 1.5. 5.5 FLOOR SLABS Floor slabs may be established upon suitable natural soils or structural fill extending to suitable natural soils, as discussed in Section 5.2.1, Site Preparation, of this report. Under no circumstances shall floor slabs be established directly over non-engineered fills, loose or disturbed soils, sod, rubbish, construction debris, other deleterious materials, frozen soils, or within ponded water. In order to facilitate curing of the concrete, it is recommended that floor slabs be directly underlain by at least 4 inches of “free-draining” fill, such as “pea” gravel or three-quarters to one-inch minus clean gap-graded gravel. 5.6 PAVEMENTS The surface fill soil, if properly prepared, will exhibit poor to moderate pavement support characteristics when saturated or nearly saturated. All pavement areas must be prepared as previously discussed (see Section 5.2.1, Site Preparation). With the subgrade soils and the projected traffic, as discussed in Section 2, Proposed Construction, the following pavement sections are recommended: Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 14 Light Parking Areas (Moderate Volume of Automobiles and Light Trucks with Occasional Medium-Weight Trucks and No Heavy-Weight Trucks) [1-3 equivalent 18-kip axle loads per day] Flexible Pavements: (Asphalt Concrete) 3.0 inches Asphalt concrete 8.0 inches Aggregate base Over Properly prepared fills, natural subgrade soils, and/or structural site grading fill extending to properly prepared fills, natural subgrade soils Rigid Pavements: (Non-reinforced Concrete) 5.5 inches Portland cement concrete (non-reinforced) 5.0 inches Aggregate base Over Properly prepared fills, natural subgrade soils, and/or structural site grading fill extending to properly prepared fills, natural subgrade soils Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 15 Primary Drive Lanes within Parking Lots (Moderate Volume of Automobiles and Light Trucks, a Light Volume of Medium-Weight Trucks, and Occasional Heavy-Weight Trucks) [6-8 equivalent 18-kip axle loads per day] Flexible Pavements: (Asphalt Concrete) 3.5 inches Asphalt concrete 10.0 inches Aggregate base Over Properly prepared fills, natural subgrade soils, and/or structural site grading fill extending to properly prepared fills, natural subgrade soils Rigid Pavements: (Non-reinforced Concrete) 6.0 inches Portland cement concrete (non-reinforced) 5.0 inches Aggregate base Over Properly prepared fills, natural subgrade soils, and/or structural site grading fill extending to properly prepared fills, natural subgrade soils For dumpster pads, we recommend a pavement section consisting of 6.5 inches of Portland cement concrete, 5.0 inches of aggregate base, over properly prepared suitable natural subgrade or site grading structural fills extending to suitable natural soils. Dumpster pads shall not be constructed overlying non-engineered fills unless heavily reinforced. These above rigid pavement sections are for non-reinforced Portland cement concrete. Concrete should be designed in accordance with the American Concrete Institute (ACI) and joint details should conform to the Portland Cement Association (PCA) guidelines. The concrete should have a minimum 28-day unconfined compressive strength of 4,000 pounds per square inch and contain 6 percent ±1 percent air-entrainment. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 16 5.7 CEMENT TYPES Laboratory tests indicate that the site soils contain negligible amounts of water soluble sulfates. Therefore, all concrete which will be in contact with the site soils may be prepared using Type I or IA cement. 5.8 GEOSEISMIC SETTING 5.8.1 General The IBC 2012 code determines the seismic hazard for a site based upon 2008 mapping of bedrock accelerations prepared by the United States Geologic Survey (USGS) and the soil site class. The USGS values are presented on maps incorporated into the IBC code and are also available based on latitude and longitude coordinates (grid points). 5.8.2 Faulting Based upon our review of available literature, no active faults are known to pass through or immediately adjacent to the site. The site is approximately 80 miles northeast of the nearest mapped fault (William Fork Mountain Fault). 5.8.3 Site Class For dynamic structural analysis, the Site Class D - Stiff Soil Profile as defined in Chapter 20 of ASCE 7 (per Section 1613.3.2, Site Class Definitions, of the IBC 2012) can be utilized. 5.8.4 Ground Motions The IBC 2012 code is based on 2008 USGS mapping, which provides values of short and long period accelerations for the Site Class B boundary for the Maximum Considered Earthquake (MCE). This Site Class B boundary represents average bedrock values for the Western United States and must be corrected for local soil conditions. The following table summarizes the peak ground and short and long period accelerations for the MCE event and incorporates the appropriate soil amplification factor for a Site Class D soil profile. Based on the site latitude and longitude (40.580123 degrees north and 104.997878 degrees west, respectively), the values for this site are tabulated on the following page. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 Page 17 Spectral Acceleration Value, T Peak Ground Acceleration Fa = 1.600 0.2 Seconds (Short Period Acceleration) SS = 17.7 F a = 1.600 SMS = 28.3 SDS = 18.9 1.0 Second (Long Period Acceleration) S1 = 31.3 F v = 2.400 SM1 = 75.1 SD1 = 50.1 Site Class D 11.3 (% g) class effects] [adjusted for site Design Values (% g) 7.1 7.5 (% g) [mapped values] Boundary Site Class B Site Coefficient 5.8.5 Liquefaction Liquefaction is defined as the condition when saturated, loose, granular soils lose their support capabilities because of excessive pore water pressure, which develops during a seismic event. Clayey soils, even if saturated, generally will not liquefy during a major seismic event. Due to the low calculated acceleration, liquefaction of the saturated sand soils within the depths penetrated are unlikely to occur. 5.9 SITE VISITS GSH must verify that all topsoil/disturbed soil, non-engineered fills, and any other unsuitable soils have been removed and that non-engineered fills have been removed and/or properly prepared and that suitable soils have been encountered prior to placing site grading fills, footings, slabs, and pavements. Maverik, Inc. Job No. 0148-080-15 Geotechnical Study-Proposed Maverik Country Store, Fort Collins, Colorado July 23, 2015 5.10 CLOSURE If you have any questions or would like to discuss these items further, please feel free to contact us at (801) 685-9190. Respectfully submitted, GSH Geotechnical, Inc. Bryan Roberts State of Utah No. 276476 Senior Geotechnical Engineer Andrew M Harris, P.E. State of Colorado No. 49863 Senior Geotechnical Engineer BNR/AMH:mmh Encl. Figure 1, Figure 2, Figures 3A Figure 4 Vicinity Map Site Plan through 3F, Boring Logs Key to Boring Log (USCS) Addressee (email) Page 18 MAVERIK, INC JOB NO. 0148-080-15 REFERENCE: ALL TRAILS - NATIONAL GEOGRAPHIC TERRAIN DATED 2015 FIGURE 1 VICINITY MAP GSH o SITE 10 0 10 20 APPROXIMATE SCALE IN FEET MAVERIK, INC JOB NO 0148-080-15 REFERENCE: ADAPTED FROM DRAWING ENTITLED “SITE PLAN” BY DIXION, DATED 2015 FIGURE 2 SITE PLAN GSH o B-1 B-2 B-3 B-4 B-5 B-6 BORING: B-1 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: 11.5' (6/26/15) ELEVATION: --- GC moist FILL loose to medium dense CL moist FILL stiff SC moist FILL very loose CL moist stiff saturated SP/ saturated SM loose See Subsurface Conditions section in the report for additional information. FIGURE 3A End of Exploration at 16.5' FINE TO COARSE SAND with some silt; reddish-brown with some fine sand; occasional layers of silty clayey fine to medium sand up to 1/2" thick; brown SILTY CLAY with some fine gravel; brown CLAYEY FINE TO COARSE SAND, FILL with some silt; some fine gravel; brown BORING LOG Page: 1 of 1 CLAYEY FINE AND COARSE GRAVEL/ DESCRIPTION REMARKS GRAVELLY CLAY, FILL Ground Surface ASPHALTIC CONCRETE PAVEMENT TO 4" with some silt; some fine to coarse sand; roadbase to 6"; brown PROJECT: Proposed Maverik Country Store CLIENT: Maverik, Inc FINE TO COARSE SANDY CLAY, FILL WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 17 BORING: B-2 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: 12.0' (6/26/15), 9.1' (6/29/15) ELEVATION: --- CL moist FILL soft/loose stiff SC moist FILL loose SM/ very moist SC medium dense saturated SP/ saturated SM loose medium dense SP saturated loose See Subsurface Conditions section in the report for additional information. FIGURE 3B BORING LOG Page: 1 of 2 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS Ground Surface FINE SANDY CLAY, FILL with some fine to coarse sand; major roots (topsoil) to 6"; brown CLAYEY FINE TO COARSE SAND, FILL with some silt; some fine gravel; brown SILTY/CLAYEY FINE SAND brown FINE TO COARSE SAND with some silt; reddish-brown grades with occasional layers of fine to coarse sand with some silt up to 12" thick FINE TO COARSE SAND with trace silt; reddish-brown WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 15 19 BORING: B-2 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 CL saturated loose stiff SM saturated medium dense See Subsurface Conditions section in the report for additional information. FIGURE 3B (continued) BORING LOG Page: 2 of 2 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS FINE TO MEDIUM SANDY CLAY with some silt; brown SILTY FINE TO COARSE SAND with some silt, occasional layers of silty fine to medium sand up to 12" thick; reddish-brown End of Exploration at 31.5' Installed 1.25” diameter slotted PVC pipe to 29.0’ 25 30 35 40 45 50 8 13 21 22 WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX BORING: B-3 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: 12.0' (6/26/15) ELEVATION: --- CL moist FILL soft/loose stiff SM slightly moist loose SM/ moist SC medium dense saturated SP saturated medium dense See Subsurface Conditions section in the report for additional information. FIGURE 3C BORING LOG Page: 1 of 1 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS Ground Surface SILTY CLAY, FILL with some fine to coarse sand; major roots (topsoil) up to 8"; brown SILTY FINE TO COARSE SAND reddish-brown SILTY/CLAYEY FINE TO MEDIUM SAND brown FINE TO COARSE SAND with trace silt; reddish-brown End of Exploration at 16.5' WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 9 9 23 11 17 7 7 18 BORING: B-4 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: 10.0' (6/26/15) ELEVATION: --- GM moist FILL medium dense CL moist FILL medium stiff SM moist loose SC/ moist to SM saturated loose SM saturated loose See Subsurface Conditions section in the report for additional information. FIGURE 3D BORING LOG Page: 1 of 1 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS Ground Surface ASPHALTIC CONCRETE PAVEMENT TO 4" SILTY/CLAYEY FINE GRAVEL, FILL with some fine to coarse sand; roadbase to 6"; brown SILTY CLAY, FILL with some fine to coarse sand; brown SILTY FINE TO COARSE SAND with some clay; reddish-brown SILTY/CLAYEY FINE TO COARSE SAND with occasional layers of fine sandy clay up to 6" thick; brown SILTY FINE TO MEDIUM SAND with occasional layers of fine to coarse sand with trace silt up to 12" thick; reddish-brown End of Exploration at 16.5' WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 6 4 3 8 BORING: B-5 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: Not Encountered (6/26/15) ELEVATION: --- GP/ moist GM FILL CL moist FILL medium stiff See Subsurface Conditions section in the report for additional information. FIGURE 3E BORING LOG Page: 1 of 1 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS Ground Surface ASPHALTIC CONCRETE PAVEMENT TO 3" FINE TO COARSE SANDY FINE GRAVEL, FILL with some silt; roadbase to 12"; brown SILTY CLAY, FILL with some fine to coarse sand and fine gravel; brown contains trace fine to coarse sand End of Exploration at 5.0' No groundwater encountered at time of drilling WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 BORING: B-6 PROJECT NUMBER: 0148-080-15 DATE STARTED: 6/26/15 DATE FINISHED: 6/26/15 LOCATION: Southwest Corner Mulberry Street and Frontage Road, Fort Collins, Coloardo GSH FIELD REP.: RAG DRILLING METHOD/EQUIPMENT: 3-3/4" ID Hollow-Stem Auger HAMMER: Automatic WEIGHT: 140 lbs DROP: 30" GROUNDWATER DEPTH: Not Encountered (6/26/15) ELEVATION: --- GM/ moist GP FILL CL moist FILL medium stiff See Subsurface Conditions section in the report for additional information. FIGURE 3F BORING LOG Page: 1 of 1 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store DESCRIPTION REMARKS Ground Surface ASPHALTIC CONCRETE PAVEMENT TO 4" FINE TO COARSE SANDY FINE AND COARSE GRAVEL, FILL roadbase to 18"; brown SILTY CLAY, FILL with some fine to coarse sand; brown End of Exploration at 5.0' No groundwater encountered at time of drilling WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 0 5 10 15 20 25 CLIENT: Maverik, Inc PROJECT: Proposed Maverik Country Store PROJECT NUMBER: 0148-080-15 ① ② ③ ④ CEMENTATION: MODIFIERS: Trace <5% Some 5-12% With > 12% USCS STRATIFICATION: SYMBOLS Occasional: One or less per 6" of thickness Numerous; More than one per 6" of thickness Note: Dual Symbols are used to indicate borderline soil classifications. ⑨ Inorganic Clays of High Plasticity, Fat Clays Thin Wall OH Organic Silts and Organic Clays of Medium to High Plasticity HIGHLY ORGANIC SOILS 3.25" OD, 2.42" ID D&M Sampler OL Organic Silts and Organic Silty Clays o f Low Plasticity 3.0" OD, 2.42" ID D&M Sampler FIGURE 4 KEY TO BORING LOG ⑫ % Passing 200: Fines content of soils sample passing a No. 200 sieve; expressed as a percentage. CH (appreciable amount of fines) SC Clayey Sands, Sand-Clay Mixtures Rock Core PT Peat, Humus, Swamp Soils with High Organic Contents WATER SYMBOL Water Level Inorganic Clays of Low to Medium Plasticity, Gravelly Clays, Sandy Clays, Silty Clays, Lean Clays FINE- GRAINED SOILS More than 50% of material is smaller than No. 200 sieve size. SILTS AND CLAYS Liquid Limit less than 50% ML Inorganic Silts and Very Fine Sands, Rock Flour, Silty or Clayey Fine Sands or Clayey Silts with Slight Plasticity No Recovery CL SILTS AND CLAYS Liquid Limit greater than 50% MH Inorganic Silts, Micacious or Diatomacious Fine Sand or Silty Soils California Sampler SP Poorly-Graded Sands, Gravelly Sands, Little or No Fines Bulk/Bag Sample SANDS WITH FINES SM Silty Sands, Sand-Silt Mixtures Standard Penetration Split Spoon Sampler (appreciable amount of fines) GC Clayey Gravels, Gravel-Sand-Clay Mixtures TYPICAL SAMPLER SANDS More than 50% of coarse fraction passing through No. 4 sieve. CLEAN SANDS SW Well-Graded Sands, Gravelly Sands, Little or No Fines GRAPHIC SYMBOLS (little or no fines) Seam up to 1/8" Layer 1/8" to 12" (little or no fines) GP Poorly-Graded Gravels, Gravel-Sand Mixtures, Little or No Fines GRAVELS WITH FINES GM Silty Gravels, Gravel-Sand-Silt Mixtures Descriptions and stratum lines are interpretive; field descriptions may have been modified to reflect lab test results. Descriptions on the logs apply only at the specific boring locations and at the time the borings were advanced; they are not warranted to be representative of subsurface conditions at other locations or times. UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) MAJOR DIVISIONS TYPICAL DESCRIPTIONS DESCRIPTION THICKNESS COARSE- GRAINED SOILS More than 50% of material is larger than No. 200 sieve size. GRAVELS More than 50% of coarse fraction retained on No. 4 sieve. CLEAN GRAVELS GW Well-Graded Gravels, Gravel-Sand Mixtures, Little or No Fines Moist: Damp but no visible water. ⑦ Moisture (%): Water content of soil sample measured in laboratory; expressed as percentage of dryweight of Strongly: Will not crumble or break with finger pressure. Saturated: Visible water, usually soil below water table. ⑧ Dry Density (pcf): The density of a soil measured in laboratory; expressed in pounds per cubic foot. ⑤ Blow Count: Number of blows to advance sampler 12" beyond first 6", using a 140-lb hammer with 30" drop. MOISTURE CONTENT (FIELD TEST): Weakly: Crumbles or breaks with handling or slight finger pressure. Dry: Absence of moisture, dusty, dry to the touch. ⑥ Sample Symbol: Type of soil sample collected at depth interval shown; sampler symbols are explained below. Moderately: Crumbles or breaks with considerable finger pressure. ⑪ Plasticity Index (%): Range of water content at which a soil exhibits plastic properties. ③ Description: Description of material encountered; may include color, moisture, grain size, density/consistency, ⑫ Remarks: Comments and observations regarding drilling or sampling made by driller or field personnel. May include other field and laboratory test results using the following abbreviations: ④ Depth (ft.): Depth in feet below the ground surface. DESCRIPTION REMARKS p COLUMN DESCRIPTIONS ① Water Level: Depth to measured groundwater table. See symbol below. ⑩ Liquid Limit (%): Water content at which a soil changes from plastic to liquid behavior. ② USCS: (Unified Soil Classification System) Description of soils encountered; typical symbols are explained below. WATER LEVEL U S C S DEPTH (FT.) BLOW COUNT SAMPLE SYMBOL MOISTURE (%) DRY DENSITY (PCF) % PASSSING 200 LIQUID LIMIT (%) PLASTICITY INDEX 7 15 17 24 42 4 10 17 17 20 13 9 12 93 10 8 10 8 9 38 22 4.1 SURFACE The site is located at the south end of the existing America’s Best Value Inn and Suites property at 4333 East Mulberry Street in Fort Collins, Colorado. Demolition of the existing restaurant will be required to facilitate the construction of the proposed store. Asphalt paved parking and access is located to the east and north of the planned new store. The existing pavements vary from poor