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HomeMy WebLinkAboutCHRISTIAN BROTHERS AUTOMOTIVE - FDP - FDP170034 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL INVESTIGATION REPORT PROPOSED CHRISTIAN BROTHERS AUTOMOTIVE EAST PROSPECT ROAD AND ACADEMY COURT FORT COLLINS, COLORADO 80525 PREPARED FOR: Christian Brothers Automotive Corporation 17725 Katy Freeway, Suite 200 Houston, Texas 77094 PREPARED BY: 5319 University Drive, Suite 20 Irvine, California 92612 Report Date: December 15, 2016 Project Number: 16-1137 5319 University Drive, Suite 20 Irvine, California 92612 (949) 278-0897 Project #16-1137 1 December 15, 2016 Mr. Curtis Cain Christian Brothers Automotive Corporation 17725 Katy Freeway, Suite 200 Houston, Texas 77094 RE: Geotechnical Investigation Report Proposed Christian Brothers Automotive East Prospect Road and Academy Court Fort Collins, Colorado 80525 Earth Science Project Number: 16-1137 Dear Mr. Cain: Earth Science LLC (Earth Science), in conjunction with American GeoServices, LLC (Geotechnical Testing Engineer), is pleased to provide the results of the Geotechnical Investigation Report (Report) for the above-mentioned address (Subject Property) to Christian Brothers Automotive Corporation (CBAC). The objective of the attached Report was to explore the subsurface conditions at the Subject Property to obtain information on the physical and engineering properties of the soil and to develop geotechnical engineering recommendations for the design and construction of an approximately 5,057 square foot automotive service facility at the Subject Property, as well as other improvements such as paved driveways and parking areas. The investigation included the advancement of six Standard Penetration Test (SPT) borings (identified as B1 through B6) to varying terminal depths between 6.0 and 10.0 feet below ground surface (bgs) using a truck-mounted drill rig. All six borings encountered auger refusal due to boulders/cobbles; therefore, three test pits (identified as TP1 through TP3) were also advanced at the Subject Property using a backhoe. Groundwater was not encountered in any of the six borings or the three test pits advanced at the Subject Property. The attached Report provides the results of the field investigation and the corresponding conclusions and recommendations. Project #16-1137 2 Earth Science appreciates the opportunity to be of service to CBAC. If you have any questions concerning the attached Report, or if we can assist you with any other matter, please contact the undersigned at (949) 278-0897. Respectfully, Sean Rakhshani Principal Geotechnical Summary Proposed Auto Retail Facility E. Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 Page 1 of 3 December 15, 2016 GEOTECHNICAL SUMMARY American GeoServices, LLC (AGS) performed a geotechnical evaluation of the subject site located north of E. Prospect Rd and east of Academy Ct in Ft Collins. Results of our evaluation are summarized below. SUBSURFACE CONDITIONS: During December 2016, six Standard Penetration Test (SPT) borings (B1 through B6) were drilled in the proposed construction area at locations shown below. Due to the shallow refusal depth to auger drilling, three test pits (TP-1 through TP-3) were dug to evaluate the gravelly/cobbly subsurface soil conditions present at the site. Geotechnical Summary Proposed Auto Retail Facility E. Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 Page 2 of 3 December 15, 2016 Fill: Site is underlain by fill consisting of mixtures of sand, clay, gravel, and cobbles (SC, GC) in the middle portion (TP2, B2, B4, B5) of the site in upper about 4-6 feet. At some locations, fill may also consist of construction debris and organics. Native Alluvium: Besides the middle portion, the site is underlain by medium dense to dense mixtures of clays, sands, gravel, and cobbles (SC, GW) extending to the maximum explored depth of 12 feet. In the middle portion, fill is underlain by the same native alluvium. Onsite soils are, in general, non-plastic or with low plasticity. Groundwater: Groundwater was not encountered during our exploration or after the completion of drilling. These observations may not be indicative of other times or at locations other than the site. Some variations in the groundwater level may be experienced in the future. The magnitude of the variation will largely depend upon the duration and intensity of precipitation, temperature and the surface and subsurface drainage characteristics of the surrounding area. SITE PREPARATION / EXCAVATION: Materials encountered at this site may be excavated with conventional mechanical excavating equipment. OSHA Type C soils will be encountered at this site during excavation. OSHA recommends maximum allowable unbraced temporary excavation slopes of 1.5:1(H:V) for Type C soils for excavations up to 10 feet deep. COMPACTION REQUIREMENTS: Fill under the foundations should be granular, non-expansive and free from organics and non-soil materials. Imported structural fill should consist of sand or gravel material with a maximum particle size of 3 inches or less. In addition, this material shall have a liquid limit less than 30 and a plasticity index of 15 or less. Structural fill should also have a percent fine between 15 to 30 percent passing the No. 200 sieve. Structural fill should be moisture conditioned to within 2 percent of OMC and compacted to at least 95 percent of Standard Proctor (ASTM D698) maximum dry density. Compaction in the wall backfill areas should be 85% or greater. FOUNDATIONS: The proposed structures can be supported on conventional shallow foundations designed and constructed using the following recommendations: Over-excavate the foundation subgrades by 2-3 feet to remove unsuitable fill and to prepare a uniform subgrade. Surficially compact the excavated subgrade and call AGS for open-hole inspection. After the subgrade is inspected and approved, backfill with granular free-draining structural fill compacted to at least 95% of ASTM D698 maximum dry density. This recommendation can be modified or eliminated provided an open-hole inspection is performed by AGS to evaluate subgrade soil moisture conditions, soil consistency, and soil uniformity at the foundation level, at the time of construction. Geotechnical Summary Proposed Auto Retail Facility E. Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 Page 3 of 3 December 15, 2016 Provided above recommendations are strictly followed, foundations can be designed for a maximum allowable bearing capacity of 2,000 pounds per square foot (psf). For lateral load resistance, passive earth pressure value of 300 pcf equivalent fluid density may be used. A coefficient of friction value of 0.4 (unfactored) may be used for concrete foundation against sandy subgrade. SLAB-ON-GRADE: The “Slab Performance Risk” associated with existing sandy soils is “Low.” For design of floor slabs, a modulus of subgrade reaction of 200 pounds per cubic inch (pci) may be used provided slab-on-grade is placed on properly prepared subgrades after the completion of soil modification procedures described earlier. PAVEMENTS: Based on the results of our subsurface exploration, we anticipate sandy soil subgrades for pavements, which is equivalent to soil classification A-2 in accordance with American Association of State Highway and Transportation Officials (AASHTO). All pavement subgrades should be proof-rolled and approved by a registered geotechnical engineer from our office prior to the placement of base rock or pavement materials. We used the modified AASHTO pavement design method for the design of pavements and assumed standard Equivalent Daily Load Application (EDLA) or Equivalent Single Axle Load (ESAL) values for automobile parking, access driveways, and fire lanes for a typical townhomes project and a design life of 20 years. Results of our design are summarized below. Pavement Area Full-depth AC (Inches) AC + ABC (Inches) PCC Parking 5.0 3.0 AC + 6.0 ABC 5.5 Driveways, Fire Lanes, and Heavy Traffic / Loading Areas 6.5 4.5 AC + 6.0 ABC 6.0 AC: Asphaltic Concrete; ABC: Aggregate Base Course; PCC: Portland Cement Concrete Mailing: 1281 E. Magnolia St D250 Ft. Collins, CO 80524 Ph: (303) 325 3869 www.americangeoservices.com sma@americangeoservices.com Ph: (888) 276 4027 Fx: (877) 471 0369 Mailing: 191 University Blvd, #375 Denver, CO 80206 Ph: (303) 325 3869 December 15, 2016 PROJECT NO: 0326-D16 Mr. Sean Rakhshani Earth Science LLC 2967 Michelson Drive, Suite G299 Irvine, California Re: Geotechnical Evaluation Report, Proposed Automotive Store, E. Prospect Rd & Academy Ct, Ft Collins, Colorado Dear Mr. Rakhshani, At your request, we have completed the geotechnical evaluation for the referenced project. Results of our evaluation and design recommendations are described below. PROJECT INFORMATION The site is located north of E. Prospect Rd and east of Academy Ct in Ft Collins as shown in Figure 1 and Figure 2. The site is roughly a triangular-shaped barren parcel of land situated adjacent to Great Western Railway property. Site topography is relatively flat. The proposed development will consist of building an automotive commercial retail structure. We do not anticipate significant site grading or basement for this project. We anticipate proposed structures will be constructed with light to moderate foundation loads. If these proposed conditions change, we should be contacted to modify our report. Geotechnical, Geostructural, Environmental, Groundwater, Pavements, and Building Assessments Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 2 of 13 SCOPE OF WORK During December 2016, six Standard Penetration Test (SPT) borings (B1 through B6) were drilled in the proposed construction area at locations shown in Figure 2. Using a CME 55 equivalent drill rig, SPT borings were extended to the maximum exploration depth of approximately 10 feet below the existing ground surface. The drill rig was equipped with 4.0-inch diameter, solid-stem continuous-flight augers. The augers were used to advance the boreholes and samples were obtained using a 2-inch, outside-diameter split-spoon sampler. The sampler was driven using a standard hammer weighing 140 pounds falling a distance of 30 inches. The sampler was first seated into the bottom of the borehole, and then driven 12 inches. The number of blows required driving the sampler 12 inches, or a fraction thereof, constitutes a penetration test and is similar to the SPT testing standards as per American Society for Testing and Materials ASTM D1586. The penetration tests, when properly evaluated, provide an index to the soil strength and density of the material tested. The penetration test results are shown on the individual Borehole Log included in an Appendix. The Legend and Notes necessary to interpret our Borehole Logs are also included in an appendix. After the completion of drilling, all boring locations were backfilled with soil cuttings. Remaining soil cuttings were removed from the site and the entire site was left clean. Samples of subsurface soil materials were collected at regular intervals during drilling. The samples were visually inspected, logged, placed in a sealed container, and transported to testing laboratory for further visual evaluation. Groundwater level measurements were taken during drilling and after the completion of drilling. Due to the shallow refusal depth to auger drilling, three test pits (TP-1 through TP-3) were dug to evaluate the gravelly/cobbly subsurface soil conditions present at the site. Soil samples were collected at regular depth intervals and transported to the laboratory for further evaluation. Test pits were backfilled with excavated soils and compacted with the excavator but not as structural fill. Data obtained from site observations, subsurface exploration, laboratory evaluation, and previous experience in the area was used to perform engineering analyses. Results of engineering analyses were then used to reach conclusions and recommendations presented in this report. SUBSURFACE CONDITIONS Subsurface conditions encountered in our explorations are described in detail in the exploration logs provided in an Appendix. Soil classification and identification are based on commonly accepted methods employed in the practice of geotechnical engineering. In some cases, the stratigraphic boundaries shown on Borehole Logs represent transitions between soil types rather than distinct lithological boundaries. It should be recognized that subsurface conditions often vary both with depth and laterally between individual borehole locations. The following is a summary of the subsurface conditions encountered at the site: Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 3 of 13 Fill: Site is underlain by fill consisting of mixtures of sand, clay, gravel, and cobbles (SC, GC) in the middle portion (TP2, B2, B4, B5) of the site in upper about 4-6 feet. At some locations, fill may also consist of construction debris and organics. Native Alluvium: Besides the middle portion, the site is underlain by medium dense to dense mixtures of clays, sands, gravel, and cobbles (SC, GW) extending to the maximum explored depth of 12 feet. In the middle portion, fill is underlain by the same native alluvium. Onsite soils are, in general, non-plastic or with low plasticity. Groundwater: Groundwater was not encountered during our exploration or after the completion of drilling. These observations may not be indicative of other times or at locations other than the site. Some variations in the groundwater level may be experienced in the future. The magnitude of the variation will largely depend upon the duration and intensity of precipitation, temperature and the surface and subsurface drainage characteristics of the surrounding area. Seismicity: Based on the results of our subsurface explorations and review of available literature (2006 International Building Code, Table No. 1613.5.2), in our opinion, a site classification “D” may be used for this project. However, this site classification may be revised by performing a site-specific shear wave velocity study. We do not anticipate seismically induced liquefaction potential at the site. GEOTECHNICAL CONSIDERATIONS The site is suitable for the proposed construction provided following recommendations are strictly followed. It should be noted that our recommendations are intended as guidance. They are based on our interpretation of the geotechnical data obtained during our evaluation and following assumptions: Proposed/Final site grades will not differ significantly from the current site grades; Proposed foundations will be constructed on level ground; and Structural loads are static in nature. Following construction recommendations are provided to highlight aspects of construction that could affect the design of the project. Entities requiring information on various aspects of construction must make their own interpretation of the subsurface conditions in order to determine construction methods, cost, equipment, and work schedule. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 4 of 13 CONVENTIONAL SHALLOW FOUNDATION The proposed structures can be supported on conventional shallow foundations provided following conditions are met. If these conditions cannot be met, then we should be contacted to provide specific recommendations or to modify following recommendations: Conventional shallow foundations should be designed and constructed using the following recommendations: Over-excavate the foundation subgrades by 2-3 feet to remove unsuitable fill and to prepare a uniform subgrade. Surficially compact the excavated subgrade and call AGS for open-hole inspection. After the subgrade is inspected and approved, backfill with granular free-draining structural fill compacted to at least 95% of ASTM D698 maximum dry density. This recommendation can be modified or eliminated provided an open-hole inspection is performed by AGS to evaluate subgrade soil moisture conditions, soil consistency, and soil uniformity at the foundation level, at the time of construction. Install adequate reinforcement and perimeter/foundation drains as shown in Figure 3 & 4. All drainage systems should be discharged into suitable receptacles. Positive drainage away from buildings must be maintained at all times. Pour concrete only after all foundation subgrades and foundation drains are inspected and approved by a registered geotechnical engineer from our office. Provided above recommendations are strictly followed, foundations can be designed for a maximum allowable bearing capacity of 2,000 pounds per square foot (psf). For lateral load resistance, passive earth pressure value of 300 pcf equivalent fluid density may be used. A coefficient of friction value of 0.4 (unfactored) may be used for concrete foundation against sandy subgrade. Estimated final structural loads will dictate the final form and size of foundations to be constructed. However, as a minimum, we recommend bearing walls be supported by continuous footings of at least 24 inches in width. Isolated columns should be supported on pads with minimum dimensions of 36 inches square. Continuous foundation walls should be reinforced in the top and bottom to span an unsupported length of at least 8 feet to further aid in resisting differential movement. See Figure 3. Exterior footings and footings in unheated areas should extend below design frost depth of 36 inches. We estimate total settlement for foundations designed and constructed as discussed in this section will be one inch or less, with differential settlements on the order of one-half to three-fourths of the total settlement. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 5 of 13 SLAB-ON-GRADE The “Slab Performance Risk” associated with existing sandy soils is “Low.” Slab-on-grade is a viable option, however, the owner should be aware that there is always some potential risk associated with slab movement. A structural slab or a PTS slab is always a more reliable option, especially if the owner is not willing to assume any risk. The actual slab movements that will occur on a particular project site are very difficult, if not impossible, to predict accurately because these movements depend on loads, evapo-transpiration cycles, surface and subsurface drainage, and settlement / collapse characteristics. The actual time of year during which the slab- on-grade is constructed has been found to have a large influence on future slab-on-grade movements. Slab settlements are normally defined in terms of "total" and "differential" movement. "Total" movement refers to the maximum amount of settlement that the slab may experience as a whole. "Differential" movement refers to unequal settlement that different points of the same slab may experience, sometimes over relatively short horizontal distances. Differential movements are arbitrarily determined to be one-half of the total movement in soils exhibiting Low Slab Performance Risk. Greater differential movements can occur in areas where loess soils have been encountered and where the natural soils abruptly transition to fill material. For design of floor slabs, a modulus of subgrade reaction of 200 pounds per cubic inch (pci) may be used provided slab-on-grade is placed on properly prepared subgrades after the completion of soil modification procedures described earlier. We recommend that the construction measures outlined in the following paragraphs be followed to reduce potential damage to floor slabs, should wetting of the subsurface soils occur: Separate floor slab from all bearing walls and columns with expansion joints to allow unrestrained vertical movement. Under any circumstances, floor slab should not extend beneath exterior doors or over foundation grade beams without saw cutting the slab at the beam after construction. Provide slip joints around exterior walls, interior non-bearing partitions. The connections between the interior, slab-supported partitions and exterior foundation supported walls should allow for differential movement. For slab-bearing masonry block partitions, provide slip joints at the top of the walls. Notwithstanding, if the floor moves, the partition walls may still show signs of structural distress such as cracking. If partition walls, masonry block walls, or any other walls without bottom slip joints are required, it is best to support them on grade beams which are, in turn, supported on piers. In other words, construct the slab independent of all foundations. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 6 of 13 If options are not available and slab-bearing partition walls are necessary, then the potential for structural distress may be reduced by connecting the partition walls to exterior walls using slip channels. Frequent control joints should be provided at about 10 feet spacing in the floor slab to reduce problems with shrinkage and cracking according to ACI specifications. Control joint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete slab thickness, joint spacing, and reinforcement should be established by the designer, based on experience, recognized design guidelines and the intended slab use. Placement and curing conditions will have a strong impact on the final concrete slab integrity. Floor slabs should be adequately reinforced. The need for a vapor barrier will depend on the sensitivity of floor coverings to moisture. If moisture sensitive floor coverings are proposed for portions of the proposed structure, a capillary break material, typically consisting of a “clean” gravel, should be considered. We can provide additional recommendations if this is the case. Provided gravel is desired below the slab, a layer of 4 to 6 inches can be used. Plumbing passing through slabs should be isolated from the slabs and provided with flexible connections to allow for movement. A positive bond break should be provided where plumbing lines enter through the slab. Under slab, plumbing should be avoided if possible and should be brought above the slab as soon as possible. Where mechanical equipment and HVAC equipment are supported on slabs, we recommend provision of a flexible connection between the furnace and ductwork with a minimum of 1.5 inches of vertical movement. Sidewalks and other exterior flatwork should be separated from the slab and the slab should be designed as an independent unit. RETAINING WALLS We do not anticipate the use of basement walls on this project. In any case, foundation walls, and basement walls, if used, should be designed to be rigid (unyielding), and not free to rotate. Retaining walls for at-rest conditions can be designed to resist an equivalent fluid density of 50 pcf for on-site materials. If needed, only imported granular backfill meeting CDOT Class 1 structural backfill should be used. Retaining walls for unrestrained conditions (free lateral movement) can be designed to resist an equivalent fluid density of 45 pcf for on-site fill materials and 35 pcf for imported granular backfill or CDOT Class 1 structural backfill. For passive resistance of unrestrained walls, we recommend passive resistance of 300 psf per foot of wall height. A coefficient of friction value of 0.35 may be used for contact between the prepared soil surface and concrete base. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 7 of 13 The above recommended values do not include a factor of safety or allowances for surcharge loads such as adjacent foundations, sloping backfill, vehicle traffic, or hydrostatic pressure. The above recommended values do not include hydrostatic pressures as they are based on drained conditions. We should be contacted to provide additional recommendations for any specific site retaining conditions. Retaining wall backfill should be placed in strict accordance with our earthwork recommendations given below. Backfill should not be over-compacted in order to minimize excessive lateral pressures on the walls. As a precautionary measure, a drainage collection system (drains or geosynthetic drains) should be included in the wall design in order to minimize hydrostatic pressures. A prefabricated drainage composite or drain board such as the MiraDrain 2000 or an engineer-approved equivalent may be installed along the backfilled side of the basement foundation wall. SUBSURFACE DRAINAGE High groundwater was not encountered during or after the completion of drilling. Nevertheless, proper subsurface drainage is critical for long-term performance of the proposed structures. As a minimum, recommendations illustrated in Figure 4 and given below should be strictly followed. A perimeter drain/dewatering system should be installed to reduce the potential for groundwater entering into foundation and slab areas. The lot-specific perimeter dewatering systems should be properly designed and connected to the suitable discharge from the lot. The subgrade beneath a structural floor system should be graded so that water does not pond. In addition, drain laterals that span the crawl space are recommended to prevent ponding of water within the crawlspace. As a minimum, the subsurface drainage system should consist typically of 4-inch minimum diameter perforated rigid PVC pipe surrounded by at least one pipe diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to prevent fine soils from clogging the system in the future. The pipe should drain by gravity to a suitable all-weather outlet or to a properly designed area underdrain system. If an outlet or area underdrain is not available, the subsurface drainage system should be sloped to sump pits with sump pumps having standby capacity in the event of pump failure. Surface cleanouts of the perimeter drain should be installed at minimum serviceability distances around the addition. A properly constructed drain system can result in a reduction of moisture infiltration of the subsurface soils. Drains which are improperly installed can introduce settlement of the subsurface soils and could result in improper surface grading only compounding the potential issues. The entire design and construction team should evaluate, within their respective field of expertise, the current and potential sources of water throughout the life of the structure and provide any design/construction criteria to alleviate the potential for moisture changes. If recommended drain Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 8 of 13 systems are used, the actual design/layout, outlets, and location should be designed by AGS. The construction means and methods should be observed by a representative of AGS. SURFACE DRAINAGE Proper surface drainage should be maintained at the site during and after completion of construction operations. Based on the intended use of the proposed facility, all drainage recommendations provided local, state, and federal regulatory agencies should be strictly followed. As a minimum, recommendations illustrated in Figure 4 and given below should be implemented. It is important to follow these recommendations to minimize wetting or drying of the foundation elements throughout the life of the facility. Construction means and methods should also be utilized which minimize improper increases/decreases in the moisture contents of the soils during construction. The ground surface adjacent to buildings should be sloped to promote rapid run-off of surface water. We recommend a minimum slope of six inches in the first five horizontal feet for landscaped or graveled areas. These slopes should be maintained during the service life of buildings. Landscaping should be limited around building areas to either xeri-scaping, landscaping gravel, or plants with low moisture requirements. Irrigation should be minimal and limited to maintain plants. Roof downspouts should discharge on splash-blocks or other impervious surfaces and directed away from the building. Ponding of water should not be allowed immediately adjacent to the building. Upper 2 feet of exterior grading or landscaping fill placed immediately adjacent to the building (within 10ft) should be relatively impervious to minimize water infiltration adjacent to the building. Do not use plastic membrane in lieu of impervious fill to cover the ground surface. Again, positive drainage away from the new structures is essential to the successful performance of foundations and flatwork, and should be provided during the life of the structure. Paved areas within 10 feet of structures should slope at a minimum of 2 percent away from foundations, and landscape areas within 10 feet of structures should slope away at a minimum of 8 percent. Downspouts from all roof drains, if any, should cross all backfilled areas such that they discharge all water away from the backfill zones and structures. Drainage should be created such that water is diverted away from building sites and away from backfill areas of adjacent buildings. EARTHWORK At the time of report preparation, grading plans were not available. If cuts and fills exceed 4 feet of depth, we should be contacted for specific earthwork recommendations, especially stability of adjacent structures, shoring requirements, cut slopes, and construction dewatering. In any case, site grading should be carefully Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 9 of 13 planned so that positive drainage away from all structures is achieved. Following earthwork recommendations should be followed for all aspects of the project. Excavation: Materials encountered at this site may be excavated with conventional mechanical excavating equipment. Although our borings did not encounter “buried” foundation elements or other structures or debris, these materials may be encountered during excavation activities. Debris materials such as brick, wood, concrete, and abandoned utility lines, if encountered, should be removed from structural areas when encountered in excavations and either wasted from the site or placed in landscaped areas. Temporary excavations should comply with OSHA and other applicable federal, state, and local safety regulations. In our opinion, OSHA Type C soils will be encountered at this site during excavation. OSHA recommends maximum allowable unbraced temporary excavation slopes of 1.5:1(H:V) for Type C soils for excavations up to 10 feet deep. Permanent cut slopes are anticipated to be stable at slope ratios as steep as 2H:1V (horizontal to vertical) under dry conditions. New slopes should be revegetated as soon as possible after completion to minimize erosion. We recommend a minimum of 10 feet of clearance between the top of excavation slopes and soil stockpiles or heavy equipment or adjacent structures (subject to approval of AGS). If braced excavations are to be used, they should be reviewed and designed by AGS. It should be noted that near-surface soils encountered at the site will be susceptible to some sloughing and excavations should be periodically monitored by AGS’s representative. If excavation is performed under water table, or excavation is made steeper than OSHA recommendations, proper shoring should be provided. It is contractor’s responsibility to assure safety during excavation and earthwork operations. Construction Dewatering: Due to the absence of high water table, construction dewatering may not be critical for this project. However, depending upon the season, we recommend developing a construction dewatering plan prior to the beginning of excavation. As a minimum, an interceptor drain outside the entire perimeter of proposed building may be considered with proper maintenance during construction. Sumps and pumps may also be required depending upon the construction season. During construction in wet or cold weather, grade the site such that surface water can drain readily away from the building areas. Promptly pump out or otherwise remove any water that may accumulate in excavations or on subgrade surfaces, and allow these areas to dry before resuming construction. Berms, ditches and similar means may be used to prevent storm water from entering the work area and to convey any water off-site efficiently. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 10 of 13 Fill Placement: Fill material should be placed under proper moisture control, in uniform horizontal layers (lifts) not exceeding 8 inches, before compacting to the required density and before successive layers are placed. If the contractor's equipment is not capable of properly moisture conditioning and compacting 8- inch lifts, then the lift thickness shall be reduced until satisfactory results are achieved. Fill under the foundations should be granular, non-expansive and free from organics and non-soil materials. Imported structural fill should consist of sand or gravel material with a maximum particle size of 3 inches or less. In addition, this material shall have a liquid limit less than 30 and a plasticity index of 15 or less. Structural fill should also have a percent fine between 15 to 30 percent passing the No. 200 sieve. Structural fill should be moisture conditioned to within 2 percent of OMC and compacted to at least 95 percent of Standard Proctor (ASTM D698) maximum dry density. Compaction in the wall backfill areas should be 85% or greater. Permanent fill slopes are anticipated to be stable at slope ratios as steep as 2H:1V (horizontal to vertical) under dry conditions. New slopes should be revegetated as soon as possible after completion to minimize erosion. Cold Weather Construction: If earthwork is performed during the winter months when freezing is a factor, no grading fill, structural fill or other fill should be placed on frosted or frozen ground, nor should frozen material be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. A good practice is to cover the compacted fill with a “blanket” of loose fill to help prevent the compacted fill from freezing overnight. The “blanket” of loose fill should be removed the next morning prior to resuming fill placement. During cold weather, foundations, concrete slabs-on-grade, or other concrete elements should not be constructed on frozen soil. Frozen soil should be completely removed from beneath the concrete elements, or thawed, scarified and re-compacted. The amount of time passing between excavation or subgrade preparation and placing concrete should be minimized during freezing conditions to prevent the prepared soils from freezing. Blankets, soil cover or heating as required may be utilized to prevent the subgrade from freezing. CONCRETE & STEEL CONSTRUCTION Concrete sidewalks and any other exterior concrete flatwork around the proposed structure may experience some differential movement and cracking. While it is not likely that the exterior flatworks can be economically protected from distress, we recommend following techniques to reduce the potential long- term movement: Scarify and re-compact at least 12 inches of subgrade material located immediately beneath structures. Avoid landscape irrigation and moisture holding plants adjacent to structures. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 11 of 13 Thicken or structurally reinforce the structures. We recommend Class 2 sulfate resistance as per ACI 201 standards for all concrete in contact with the soil on this site. Calcium chloride should not be added. Concrete should not be placed on frost or frozen soil. Concrete must be protected from low temperatures and properly cured. We anticipate corrosive potential for on-site soils. A qualified corrosion professional should evaluate site conditions and provide proper recommendations for buried metal structures. PAVEMENT DESIGN & CONSTRUCTION Based on the results of our subsurface exploration, we anticipate sandy soil subgrades for pavements, which is equivalent to soil classification A-2 in accordance with American Association of State Highway and Transportation Officials (AASHTO). All pavement subgrades should be proof-rolled and approved by a registered geotechnical engineer from our office prior to the placement of base rock or pavement materials. We used the modified AASHTO pavement design method for the design of pavements and assumed standard Equivalent Daily Load Application (EDLA) or Equivalent Single Axle Load (ESAL) values for automobile parking, access driveways, and fire lanes for a typical townhomes project and a design life of 20 years. Results of our design are summarized below. Pavement Area Full-depth AC (Inches) AC + ABC (Inches) PCC Parking 5.0 3.0 AC + 6.0 ABC 5.5 Driveways, Fire Lanes, and Heavy Traffic / Loading Areas 6.5 4.5 AC + 6.0 ABC 6.0 AC: Asphaltic Concrete; ABC: Aggregate Base Course; PCC: Portland Cement Concrete If specific pavement loading is planned or if some of our recommendations given here cannot be followed, we should be contacted immediately. We recommend the use of PCC (instead of AC) in areas of loading/unloading, concentrated loading, and turning movements by heavy vehicles. These areas typically include delivery zones, entrances and trash collection/dumpster locations. All PCC pavement should have adequate construction joints, including longitudinal and transverse joints. All joints should be formed during construction or sawed into freshly setting concrete prior to uncontrolled cracking. All formed joints should be properly sealed. Proper curing procedures should be used to protect PCC pavements from moisture loss, freezing, rapid temperature change, and mechanical injury. Traffic should not be allowed during the first week after pavement construction. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 12 of 13 Pavement areas should be properly graded and adequate drainage provided in order to assure quick removal of water or surface run-off from pavement areas. Ponding of water should not be allowed. All joints and curb areas should be properly sealed to minimize water infiltration. Proper and routine maintenance including annual crack repair and 5-6 year overlays should be performed to assure long-term performance of AC pavements. Similarly, regular maintenance and sealing of concrete joints should be done for PCC pavements. Deicing salts should not be used during the first year after pavement construction. All pavement materials and placement methods should conform to the requirements given in the most current Colorado Department of Transportation’s (CDOT) “Standard Specifications for Road and Bridge Construction.” In addition, all applicable specifications and requirements of the local City should be followed. Pavement materials should be submitted for our review and tested for conformance with CDOT and local City specifications. LIMITATIONS Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory evaluation, and our present knowledge of the proposed construction. It is possible that soil conditions could vary between or beyond the points explored. If soil conditions are encountered during construction that differ from those described herein, we should be notified so that we can review and make any supplemental recommendations necessary. If the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, our recommendations should also be reviewed and revised by AGS. Our Scope of Work for this project did not include any flood hazard evaluation, civil engineering evaluation of any kind, research, testing, or assessment relative to past or present contamination of the site by any source. If such contamination were present, it is very likely that the exploration and testing conducted for this report would not reveal its existence. If the Owner is concerned about the potential for such contamination, additional studies should be undertaken. We are available to discuss the scope of such studies with you. No tests were performed to detect the existence of mold or other environmental hazards as it was beyond Scope of Work. Local regulations regarding land or facility use, on and off-site conditions, or other factors may change over time, and additional work may be required with the passage of time. Based on the intended use of the report within one year from the date of report preparation, AGS may recommend additional work and report updates. Non-compliance with any of these requirements by the client or anyone else will release AGS from any liability resulting from the use of this report by any unauthorized party. Client agrees to defend, indemnify, and hold harmless AGS from any claim or liability associated with such unauthorized use or non-compliance. Proposed Automotive Store E.Prospect Rd & Academy Ct, Ft Collins, CO Project No: 0326-D16 December 15, 2016 Page No: 13 of 13 In this report, we have presented judgments based partly on our understanding of the proposed construction and partly on the data we have obtained. This report meets professional standards expected for reports of this type in this area. Our company is not responsible for the conclusions, opinions or recommendations made by others based on the data we have presented. Refer to American Society of Foundation Engineers (ASFE) general conditions included in an appendix. This report has been prepared exclusively for the client, its’ engineers and subcontractors for the purpose of design and construction of the proposed structure. No other engineer, consultant, or contractor shall be entitled to rely on information, conclusions or recommendations presented in this document without the prior written approval of AGS. We appreciate the opportunity to be of service to you on this project. If we can provide additional assistance or observation and testing services during design and construction phases, please call us at 1 888 276 4027. Sincerely, Sam Adettiwar, MS, PE, GE, P.Eng, M.ASCE Senior Engineer Attachments AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 AMERICAN GEOSERVICES, LLC (888) 276-4027 ii IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT As the client of a consulting geotechnical engineer, you should know that site subsurface conditions cause more construction problems than any other factor. ASFE/the Association of Engineering Firms Practicing in the Geosciences offers the following suggestions and observations to help you manage your risks. A GEOTECHNICAL ENG.NEERING REPORT IS BASED ON A UNIQUE SET OF PROJECT- SPECIFIC FACTORS Your geotechnical engineering report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. These factors typically include: the general nature of the structure involved, its size, and configuration; the location of the structure on the site; other improvements, such as access roads, parking lots, and underground utilities; and the additional risk created by scope-of-service limitations imposed by the client. To help avoid costly problems, ask your geotechnical engineer to evaluate how factors that change subsequent to the date of the report may affect the report's recommendations. Unless your geotechnical engineer indicates otherwise, do not use your geotechnical engineering report: MOST GEOTECHNICAL FINDINGS ARE PROFESSIONAL JUDGMENTS Site exploration identifies actual subsurface conditions only at those points where samples are taken. The data were extrapolated by your geotechnical engineer who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates, Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations. you and your geotechnical engineer can work together to help minimize their impact. Retaining your geotechnical engineer to observe construction can be particularly beneficial in this respect. when the nature of the proposed structure is changed. for example, if an office building will be erected instead of a parking garage, or a refrigerated warehouse will be built instead of an unrefrigerated one; when the size, elevation. or configuration of the proposed structure is altered; when the location or orientation of the proposed structure is modified; when there is a change of ownership; or .for application to an adjacent site. Geotechnical engineers cannot accept responsibility for problems that may occur if they are not consulted after factors considered in their report's development have changed. A REPORT'S RECOMMENDATIONS CAN 8811 Colesville Road/Suite G106/Silver Spring, MD 20910 Telephone: 301/565-2733 Facsimile: 301/589-2017 about the potential for hazardous materials existing at the site. The equipment, techniques, and personnel used to perform a geoenvironmental exploration differ substantially from those applied in geotechnical engineering. Contamination can create major risks. If you have no information about the potential for your site being contaminated. you are advised to speak with your geotechnical consultant for information relating to geoenvironmental issues. A GEOTECHNICAL ENGINEERING REPORT IS SUBJECT TO MISINTERPRETATION Costly problems can occur when other design profes- sionals develop their plans based on misinterpretations of a geotechnical engineering report. To help avoid misinterpretations, retain your geotechnical engineer to work with other project design professionals who are affected by the geotechnical report. Have your geotechnical engineer explain report implications to design professionals affected by them. and then review those design professionals' plans and specifications to see how they have incorporated geotechnical factors. Although certain other design professionals may be fam- iliar with geotechnical concerns, none knows 'as much about them as a competent geotechnical engineer. BORING LOGS SHOULD NOT BE SEPARATED FROM THE REPORT Geotechnical engineers develop final boring logs based upon their interpretation of the field logs (assembled by site personnel) and laboratory evaluation of field samples. Geotechnical engineers customarily include only final boring logs in their reports. Final boring logs should not under any circumstances be redrawn for inclusion in architectural or other design drawings. because drafters may commit errors or omissions in the transfer process. Although photographic reproduction eliminates this problem, it does nothing to minimize the possibility of contractors misinterpreting the logs during bid preparation. When this occurs. delays. disputes. and unanticipated costs ara the all-too- frequent result. To minimize the likelihood of boring log misinterpretation, give contractors ready access to the complete geotechnical engineering report prepared or authorized for their use. (If access is provided only to the report prepared for you, you should advise contractors of the report's limitations. assuming that a contractor was not one of the specific persons for whom the report was prepared and that developing construction cost estimates was not one of the specific purposes for which it was prepared. In other words. while a contractor may gain important knowledge from a report prepared for another party, the contractor would be well-advised to discuss the report with your geotechnical engineer and to perform the additional or alternative work that the contractor believes may be needed to obtain the data specifically appropriate for construction cost estimating purposes.) Some clients believe that it is unwise or unnecessary to give contractors access to their geo- technical engineering reports because they hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems. It also helps reduce the adversarial attitudes that can aggravate problems to disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY Because geotechnical engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against geotechnical engineers. To help prevent this problem, geotechnical engineers have developed a number of clauses for use in their contracts, reports, and other documents. Responsibility clauses are not exculpatory clauses designed to transfer geotechnical engineers' liabilities to other parties. Instead, they are definitive clauses that identify where geotechnical engineers' responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your geotechnical engineering report. Read them closely. Your geotechnical engineer will be pleased to give full and frank answers to any questions. RELY ON THE GEOTECHNICAL ENGINEER FOR ADDITIONAL ASSISTANCE Most ASFE-member consulting geotechnical engineering firms are familiar with a variety of techniques and approaches that can be used to help reduce risks for all parties to a construction project, from design through construction. Speak with your geotechnical engineer not only about geotechnical issues, but others as well, to learn about approaches that may be of genuine benefit. You may also wish to obtain certain ASFE publications. Contact a member of ASFE of ASFE for a complimentary directory of ASFE publications. ONLY BE PRELIMINARY The construction recommendations included in your geotechnical engineer's report are preliminary, because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Because actual subsurface conditions can be discerned only during earthwork, you should retain your geo- technical engineer to observe actual conditions and to finalize recommendations. Only the geotechnical engineer who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations are valid and whether or not the contractor is abiding by applicable recommendations. The geotechnical engineer who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. SUBSURFACE CONDITIONS CAN CHANGE A geotechnical engineering report is based on condi- tions that existed at the time of subsurface exploration. Do not base construction decisions on a geotechnical engineering report whose adequacy may have been affected by time. Speak with your geotechnical consult- ant to learn if additional tests are advisable before construction starts. Note, too, that additional tests may be required when subsurface conditions are affected by construction operations at or adjacent to the site, or by natural events such as floods, earthquakes, or ground water fluctuations. Keep your geotechnical consultant apprised of any such events. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS Consulting geotechnical engineers prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your geotechnical engineer prepared your report expressly for you and expressly for purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the geotechnical engineer. No party should apply this report for any purpose other than that originally contemplated without first conferring with the geotechnical engineer. GEOENVIRONMENTAL CONCERNS ARE NOT AT ISSUE Your geotechnical engineering report is not likely to relate any findings, conclusions, or recommendations