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HomeMy WebLinkAboutLINCOLN CORRIDOR HOTEL - PDP - PDP170026 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED STAYBRIDGE HOTEL LOT 1, BALDWIN MINOR SUBDIVISION 301 EAST LINCOLN AVENUE, FORT COLLINS, COLORADO SOILOGIC # 16-1213 September 21, 2016 Soilogic, Inc. 3050 67th Avenue, Suite 200 • Greeley, CO 80634 • (970) 535-6144 P.O. Box 1121 • Hayden, CO 81639 • (970) 276-2087 September 21, 2016 Willco XIV, LLLP 4836 S. College Avenue, Suite 11 Fort Collins, Colorado 80525 Attn: Mrs. Moira Bright Re: Geotechnical Subsurface Exploration Report Proposed Staybridge Hotel – Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue Fort Collins, Colorado Soilogic Project # 16-1213 Mrs. Bright: Soilogic, Inc. (Soilogic) personnel have completed the geotechnical subsurface exploration you requested for the proposed Staybridge Hotel to be constructed on Lot 1 in the Baldwin Minor Subdivision and a small portion of the adjacent Lot 1 in the Woodward Technology Center, located at 301 East Lincoln Avenue in Fort Collins, Colorado. The results of our subsurface exploration and pertinent geotechnical engineering recommendations are included with this report. In general, the subsurface materials encountered in the completed site borings can be summarized as follows. A thin layer of vegetation and topsoil was encountered at the surface at the locations of borings B-2, B-4 and B-9. Approximately 2½ inches of existing asphalt pavement was encountered at the surface at the location of boring B-7. Dark brown/brown/rust clayey to silty sand containing varying amounts of gravel was encountered underlying the vegetative soil layer, asphalt pavement or at the surface at the locations of the remaining site borings. A portion of the near-surface clayey/silty sand extending to a depth of about 2½ feet below ground surface at the location of boring B-6 was somewhat mottled in color and was identified as probable existing fill material which may have been placed to develop finish site grade. The clayey/silty sand varied from loose to medium dense in terms of relative density, exhibited no swell potential at current moisture and density conditions and extended to depths between approximately 1 and 6 feet below ground surface, where it transitioned to cleaner, brown/rust sand with varying amounts of silt, gravel and possible cobbles. The sand with silt and gravel varied from loose to very dense in relative density, would be expected to be non-expansive based on Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 2 the physical properties and engineering characteristics of the material and extended to the bottom of all borings at a depth of approximately 15 feet below present site grades. Groundwater was encountered in borings B-1 through B-5 at depths of approximately 11 to 13 feet below ground surface during drilling. When checked immediately after completion of drilling, groundwater was measured at depths of 12½ and 11 feet below ground surface in borings B-2 and B-3 respectively. Dry cave-ins were measured at depths of about 10, 7½ and 6 feet below ground surface in borings B-1, B-4 and B-5 respectively at that time. No groundwater was encountered to the depth explored (10 feet below ground surface) at the locations of borings B-6 through B-9 at the time of drilling. Borings B-2, B-3, B-4 and B-9 were left open to allow for a subsequent groundwater level measurement. The remainder of the site borings were backfilled upon completion. When checked two (2) days after drilling, groundwater was measured at depths of about 12 and 10 feet below ground surface in borings B-2 and B-3 respectively. Dry cave-ins were measured at depths of approximately 7 and 6 feet below ground surface in borings B-4 and B-9 at that time. Based on the subsurface conditions encountered, results of laboratory testing and type of construction proposed, it is our opinion the proposed hotel building and associated site improvements could be constructed with conventional spread footing foundations bearing on natural, undisturbed clayey/silty sand, sand and gravel and/or removal area excavation backfill consisting of the site soils (where required). The site clayey/silty sand and sand and gravel soils would be considered low volume- change (LVC) potential soils and could be used as fill to develop the site. The reconditioned near-surface site clayey/silty sand and properly placed and compacted fill consisting of on-site soils and/or similar import LVC soils could be used for support of the building floor slabs, exterior flatwork and site pavements. Pavement section design options for the site drive and parking area pavements are included with this report. Other opinions and recommendations concerning design criteria and construction details for the proposed site improvements are also provided. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 3 We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information or if we can provide any further assistance, please do not hesitate to contact us. Very Truly Yours, Soilogic, Inc. Reviewed by: Darrel DiCarlo, P.E. Wolf von Carlowitz, P.E. Senior Project Engineer Principal Engineer 44271 36746 GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED STAYBRIDGE HOTEL LOT 1, BALDWIN MINOR SUBDIVISION 301 EAST LINCOLN AVENUE, FORT COLLINS, COLORADO SOILOGIC # 16-1213 September 21, 2016 INTRODUCTION This report contains the results of the completed geotechnical subsurface exploration for the proposed Staybridge Hotel to be constructed on Lot 1 in the Baldwin Minor Subdivision and a small portion of the adjacent Lot 1 in the Woodward Technology Center in Fort Collins, Colorado. The purpose of our exploration was to describe the subsurface conditions encountered in the completed site borings and develop the test data necessary to provide recommendations concerning design and construction of the hotel building, trash enclosure, gazebo, porte-cochere, retaining wall, in-ground pool and high- mast lighting foundations and support of floor slabs, exterior flatwork and site pavements. Pavement section design recommendations are also provided. The conclusions and recommendations outlined in this report are based on results of the completed field and laboratory testing and our experience with subsurface conditions in this area. PROPOSED CONSTRUCTION We understand the proposed hotel building will be a 3-story wood-frame structure constructed as slab-on-grade. Foundation loads for the structure are expected to be light to moderate, with continuous wall loads on the order of 3.5 to 5 kips per lineal foot and individual column loads on the order of 150 kips or less. Trash enclosure, high-mast lighting, retaining wall and indoor pool construction are also anticipated. Paved drive and parking area pavements will be constructed as part of the proposed site improvements. Traffic loading on site pavements is expected to consist of low volumes of light passenger vehicles, with occasional trash and delivery truck traffic. Small grade changes (on the order of 4 feet or less) are anticipated to develop finish site grades in the building and pavement areas. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 2 SITE DESCRIPTION The development property includes Lot 1 of the Baldwin Minor Subdivision (an approximate 4-acre parcel) and a small portion of the adjacent Lot 1 in the Woodward Technology Center, located at 301 East Lincoln Avenue in south Fort Collins, Colorado. At the time of our site exploration, the existing Hydro Construction facility occupied the property. A single-story, wood-frame at-grade office, single-story at-grade brick shop/garage and other small single-story at-grade outbuildings were present on the site. Portions of the ground surface across the property were paved with asphalt concrete or gravel-surfacing, while limited areas contained a sparse to moderate growth of native grass and weed vegetation. The proposed development area extending onto the adjacent Lot 1 in the Woodward Technology Center was mostly paved with asphaltic concrete. Limited areas of this site to the south of the existing parking lot contained a sparse to moderate growth of native grass and weed vegetation or appeared barren. The site was observed to be relatively level, with a gentle overall slope downward to the south. The maximum difference in ground surface elevation across the development site is estimated to be less than 10 feet based on review of available USGS topographic maps of the area. The Cache la Poudre River was also noted near the southern property boundary. SITE EXPLORATION Field Exploration To develop site specific subsurface information, a total of nine (9) soil borings were completed across the site. Five (5) borings were drilled in the area of the proposed hotel building to a depth of approximately 15 feet below present site grades. Four (4) borings were drilled in areas of proposed drive lanes/parking areas to a depth of approximately 10 feet below present site grades. The boring locations were established in the field by Soilogic personnel based on a concept plan provided by the client dated June 7, 2016, using a mechanical surveyor’s wheel and estimating angles from identifiable site references. The boring locations should be considered accurate only to the degree implied by the methods used to make the field measurements. A diagram indicating the approximate boring locations is included with this report. Graphic logs of each of the auger borings are also included. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 3 The test holes were advanced using 4-inch diameter continuous flight auger powered by a truck-mounted CME-45 drill rig. Samples of the subsurface materials were obtained at regular intervals using California barrel and split-spoon sampling procedures in general accordance with ASTM specification D-1586. As part of the D-1586 sampling procedure, the standard sampling barrels are driven into the substrata using a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the samplers a distance of 12 inches is recorded and helpful in estimating the consistency, relative density of the soils encountered. In the California barrel sampling procedure, lesser disturbed samples are obtained in removable brass liners. Samples of the subsurface materials obtained in the field were sealed and returned to the laboratory for further evaluation, classification and testing. Laboratory Testing The samples collected were tested in the laboratory to measure natural moisture content and were visually and/or manually classified in accordance with the Unified Soil Classification System (USCS). The USCS group symbols are indicated on the attached boring logs. An outline of the USCS classification system is included with this report. As part of the laboratory testing, a calibrated hand penetrometer (CHP) was used to estimate the unconfined compressive strength of essentially-cohesive specimens. The CHP also provides a more reliable estimate of soil consistency than tactual observation alone. Dry density, Atterberg limits, -200 wash and swell/consolidation tests were completed on selected samples to help establish specific soil characteristics. Atterberg limits tests are used to determine soil plasticity. The percent passing the #200 size sieve (-200 wash test) is used to determine the percentage of fine-grained materials (clay and silt) in a sample. Swell/consolidation tests are performed to evaluate soil volume change potential with variation in moisture content. The results of the completed laboratory tests are outlined on the attached boring logs and swell/consolidation test summaries. Water Soluble Sulfates (WSS) tests were also completed on two (2) selected soil samples to evaluate corrosive soil characteristics with respect to buried concrete and results discussed subsequently in this report. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 4 SUBSURFACE CONDITIONS The subsurface materials encountered in the completed site borings can be summarized as follows. A thin layer of vegetation and topsoil was encountered at the surface at the locations of borings B-2, B-4 and B-9. Approximately 2½ inches of existing asphalt pavement was encountered at the surface at the location of boring B-7. Dark brown/brown/rust clayey to silty sand containing varying amounts of gravel was encountered underlying the vegetative soil layer, asphalt pavement or at the surface at the locations of the remaining site borings. A portion of the near-surface clayey/silty sand extending to a depth of about 2 ½ feet below ground surface at the location of boring B-6 was somewhat mottled in color and was identified as probable existing fill material which may have been placed to develop finish site grade. The clayey/silty sand varied from loose to medium dense in terms of relative density, exhibited no swell potential at current moisture and density conditions and extended to depths between approximately 1 and 6 feet below ground surface, where it transitioned to cleaner, brown/rust sand with varying amounts of silt, gravel and possible cobbles. The sand with silt and gravel varied from loose to very dense in relative density, would be expected to be non-expansive based on the physical properties and engineering characteristics of the material and extended to the bottom of all borings at a depth of approximately 15 feet below present site grades. The stratigraphy indicated on the included boring logs represents the approximate location of changes in soil and bedrock types. Actual changes may be more gradual than those indicated. Groundwater was encountered in borings B-1 through B-5 at depths of approximately 11 to 13 feet below ground surface during drilling. When checked immediately after completion of drilling, groundwater was measured at depths of 12½ and 11 feet below ground surface in borings B-2 and B-3 respectively. Dry cave-ins were measured at depths of about 10, 7½ and 6 feet below ground surface in borings B-1, B-4 and B-5 respectively at that time. No groundwater was encountered to the depth explored (10 feet below ground surface) at the locations of borings B-6 through B-9 at the time of drilling. Borings B-2, B-3, B-4 and B-9 were left open to allow for a subsequent groundwater level measurement. The remainder of the site borings were backfilled upon completion. When checked two (2) days after drilling, groundwater was measured at depths of about Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 5 12 and 10 feet below ground surface in borings B-2 and B-3 respectively. Dry cave-ins were measured at depths of approximately 7 and 6 feet below ground surface in borings B-4 and B-9 at that time. Groundwater levels will vary seasonally and over time based on weather conditions, site development, irrigation practices and other hydrologic conditions. Perched and/or trapped groundwater conditions may also be encountered at times throughout the year. Perched water is commonly encountered in soils overlying less permeable soil layers and/or bedrock. The location and amount of perched/trapped water can also vary over time. ANALYSIS AND RECOMMENDATIONS Demolition and Site Development We understand the existing office, shop/garage, outbuildings and other associated site improvements will be razed prior to construction of the hotel building. Within the new structure, exterior flatwork and pavement areas, all existing foundations, floor slabs/ flatwork, pavements and other site improvements should be completely removed. Care will be needed to ensure all in-place fill/backfill materials associated with the existing site improvements are also completely removed at this time. In addition, all tree root systems and dry and desiccated soils associated with the tree root systems should be completely removed from within the area of the proposed hotel building and beneath exterior flatwork and site pavements. The depth and extent of required removal can best be established at the time of excavation through openhole observation. If/where required, the excavated/removed materials should be replaced as controlled and compacted fill as outlined below. After stripping and completing all cuts and existing fill/backfill removal procedures and prior to placement of any new fill/backfill or flatwork concrete, we recommend the exposed subgrade soils be scarified to a depth of 9 inches, adjusted in moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. The moisture content of the scarified soils should be adjusted to be within the range of ±2% of standard Proctor optimum moisture content at the time of compaction. If some Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 6 backfilling of existing structure removal excavations is required to develop foundation bearing and/or finish floor slab subgrade elevations, we recommend the excavation be continuously benched during backfilling in order to reduce the potential for development of a shear plane between the natural site soils and controlled backfill. Fill and removal area backfill soils required to develop the site should consist of approved, low-volume-change (LVC) soils free from organic matter, debris and other objectionable materials. Based on results of the completed laboratory testing, it is our opinion existing fill (if any) and natural site clayey/silty sand and sand and gravel could be used as fill and backfill provided the proper moisture content is developed in those materials at the time of placement and compaction. Cobble-sized materials (greater than 3 inches in any dimension) should not be used as fill within 12 inches of finish floor slab, exterior flatwork and pavement subgrade elevations to reduce the potential for point- loading. If required, imported soils could consist of approved essentially-granular structural fill soils free from organic matter, debris and other objectionable materials. Import structural fill consistent with Colorado Department of Transportation (CDOT) Class 6 or 7 Aggregate Base Course specifications could be considered and would be suitable for use as engineered fill below foundations. Suitable fill and backfill soils should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted as recommended for the scarified soils above. Care should be taken to avoid disturbing all subgrade soils prior to placement of any overlying improvements. Soils which are allowed to dry out or become wet and softened or disturbed by the construction activities should be removed and replaced or reworked in place prior to concrete placement. Hotel Building Foundations Based on the subsurface conditions encountered, results of laboratory testing and type of construction proposed, it is our opinion the proposed hotel building and associated site improvements (including the lightly-loaded detached trash enclosure) could be constructed with conventional spread footing foundations bearing on natural, undisturbed clayey/silty sand, sand and gravel and/or removal area excavation backfill consisting of the onsite soils (where required). For design of continuous spread footing and isolated Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 7 column pad foundations bearing on loose to dense clayey/silty sand, sand and gravel and/or properly placed and compacted removal area backfill, we recommend using a maximum net allowable soil bearing pressure of 1,500 psf. For design of footing foundations and foundation walls to resist lateral movement, a passive equivalent fluid pressure value of 350 pcf could be used for the site clayey/silty sand, sand and gravel or similar soils. A coefficient of friction of 0.45 could be used between floor slab concrete and the bearing/subgrade soils to resist sliding. The recommended passive equivalent fluid pressure value and coefficients of friction do not include a factor of safety. Exterior footings should bear a minimum of 30 inches below finished adjacent exterior grade to provide frost protection. We recommend formed strip footings have a minimum width of 12 inches and isolated pad foundations have a minimum width of 24 inches in order to facilitate construction and reduce the potential for development of eccentrically loaded footings. Actual footing widths should be designed by a structural engineer. We estimate settlement of footing foundations designed and constructed as outlined above and resulting from the assumed structural loads would be on the order of 1 inch. Differential settlement could approach the amount of total settlement estimated above. Gazebo & High-mast Light Standard Foundations We anticipate the gazebo and high-mast light standards planned as part of site development will be constructed using shallow drilled shaft foundations. For design of shallow drilled shaft foundations bearing on loose to dense site clayey/silty sand and/or sand and gravel, we recommend using a maximum net allowable soil bearing pressure of 1,500 psf. Additional pier capacity can be developed by accounting for friction capacity between the drilled pier and surrounding clayey/silty sand and sand and gravel stratum. An allowable skin friction value of 150 psf could be used for that portion of the pier concrete in contact with the site sand soils below frost depth. Skin friction should be neglected within the top 30 inches of depth below finish grade due to the potential for frost action. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 8 Drilled shaft foundations shall bear a minimum of 30 inches below finished adjacent exterior grade to provide frost protection. For design of the foundation systems to resist overturning, a passive equivalent fluid pressure of 350 pcf could be used for that portion of the foundation system extended below frost depth. The top 30 inches of soil could be considered a surcharge load but should not be used in passive resistance calculations. A coefficient of friction of 0.45 could be used between foundation concrete and sand and gravel bearing soils to resist sliding. The recommended passive equivalent fluid pressure value and coefficient of friction do not include a factor of safety. For design of uplift resistance, an in-place soil unit weight of 120 pcf and angle of internal friction value of 30° could be used. Typically, light-pole base foundations are constructed with a minimum embedment length on the order of seven (7) feet below grade in accordance with current building code. We expect the pier excavations could be completed using conventional augering techniques. Based on the presence of essentially-granular subgrade soils, pier excavations extended more than about 5 to 6 feet below ground surface would not be expected to remain stable for short periods during construction such that temporary casing of the drilled shafts or mudded (bentonite slurry) construction procedures may be required. The presence of cobble-sized materials encountered at some locations within the sand and gravel strata may also present difficulty during drilling. Pier concrete should have a slump in the range of 5 to 7 inches and be placed in the pier holes immediately after the completion of drilling, cleaning and placement of reinforcing steel. We estimate settlement of gazebo and light-pole standard foundations designed and constructed as outlined above and resulting from the assumed structural loads would be less than 1 inch. If water from any source is allowed to infiltrate the foundation soils, additional movement of the foundations could occur. Foundation Backfill Backfill placed adjacent to foundation walls should consist of approved LVC soils free from organic matter, debris and other objectionable materials. Based on results of the completed field and laboratory testing, it is our opinion the existing fill and native site clayey/silty sand and sand and gravel could be used as backfill in this area provided care Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 9 is taken to develop the proper moisture content in those materials at the time of placement and compaction. Cobble-sized materials should be screened and removed prior to use as foundation wall backfill. We recommend the existing fill, natural site clayey/silty sand and sand and gravel or similar soils be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture and compacted as previously outlined in the “Demolition and Site Development” section of this report. Excessive lateral stresses can be imposed on un-braced foundation walls when using heavier mechanical compaction equipment. We recommend compaction of unbalanced foundation wall backfill soils be completed using light mechanical or hand compaction equipment. Seismicity Based on our review of the International Building Code (2003), a soil profile type D could be used for the site strata. Based on our review of United States Geologic Survey (USGS) mapped information, design spectral response acceleration values of SDS = .282 (28.2%) and SD1 = .119 (11.9%) could be used. Floor Slabs and Exterior Flatwork The building floor slab and exterior flatwork could be supported on reconditioned natural site soils or properly placed and compacted fill and/or removal area backfill developed as outlined in the “Demolition and Site Development” section of this report. Care should be taken to avoid placing floor slab concrete directly on cobble-sized materials in order to reduce the potential for development of point loads on the slabs. A modulus of subgrade reaction (k) value of 250 pci could be used for design of floor slabs supported on reconditioned natural site clayey/silty sand and sand and gravel soils or similar essentially-granular import LVC fill materials. Disturbed subgrades or subgrade soils that have been allowed to dry out or become wet and softened should be removed and replaced or reconditioned in place prior to floor slab and exterior flatwork construction. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 10 Floor slabs should designed and constructed as floating slabs, separated from foundation walls, columns and plumbing and mechanical penetrations by the use of block outs or appropriate isolation material. Additionally, we recommend all partition walls supported above slabs-on-grade be constructed as floating walls to help reduce the potential for differential slab-to-foundation movement causing distress in upper sections of the structure. A minimum one and one-half (1½) inch void space is recommended beneath all floating walls. Special attention to door and stair framing, drywall installation and trim carpentry should be taken to isolate those elements from the floor slabs, allowing for some differential floor slab-to-foundation movement to occur without transmitting stresses to the overlying structure. Depending on the type of floor covering and floor covering adhesive used in finished slab-on-ground areas, a vapor barrier may be required immediately beneath the floor slabs to maintain flooring product manufacturer warranties. A vapor barrier would help reduce the transmission of moisture through floor slabs. However, the unilateral moisture release caused by placing concrete on an impermeable surface can increase slab curl. The amount of slab curl can be reduced by careful selection of an appropriate concrete mix and proper placement and curing procedures. Slab curl cannot be eliminated. Soilogic recommends the owner, architect and flooring contractor consider the performance of the slab in conjunction with the proposed flooring products to help determine if a vapor barrier will be required and where best to position the vapor barrier in relation to the floor slab. Additional guidance and recommendations concerning slab- on-grade design can be found in American Concrete Institute (ACI) section 302. Exterior flatwork will experience some movement subsequent to construction as the subgrade soils increase in moisture content. Based on results of the completed field and laboratory testing, we expect the amount of movement of exterior flatwork supported on reconditioned natural site soils and/or properly placed and compacted fill would be limited. Care should be taken to ensure that when exterior flatwork moves, positive drainage will be maintained away from the structure. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 11 Retaining Walls We understand concrete retaining walls may also be constructed as part of the site development. For design of retaining wall footing foundations bearing on natural, undisturbed loose to medium dense clayey/silty sand and sand and gravel with no to low swell potential, we recommend using a maximum net allowable soil bearing pressure of 1,500 psf. The retaining wall footing foundation should bear a minimum of 30 inches below grade at the front (unretained earth) side of the wall to provide frost protection. We estimate settlement of the retaining wall footing foundation resulting from the assumed structural loads would be less than 1 inch. Differential settlement along the length of the wall could approach the amount of total settlement estimated above. Care should be taken to prevent the development of unbalanced hydrostatic loads on site retaining walls. A drainage blanket consisting of 12 inches of free-draining rock placed behind the wall and extending the full height of the wall from approximate grade at the front of the wall to approximately 12 to 18 inches below finish grade on the retained soil side of the wall should be constructed. We recommend ¾-inch or larger washed rock be used to construct the drainage blanket. The top 12 to 18 inches of retaining wall backfill should consist of an essentially-cohesive soil to reduce the potential for immediate surface water infiltration into the wall backfill. The near-surface site clayey sand would be suitable for use in this area. A filter fabric should be employed between all free- draining aggregate and adjacent soil interfaces to reduce the potential for the migration of finer-grained soils into the gap-graded rock. Weep holes or other approved methods should be employed to help transfer any collected water to the front of the wall. A water collection system, similar to a perimeter drain system could also be considered. A typical collection drain system would consist of 4- inch diameter rigid perforated pipe surrounded by a minimum of 6 inches of the free- draining aggregate and placed at the base of the retained soils side of the wall. The invert of the drain pipe at the high point of the system should be placed at approximate front-of- wall grade and sloped a minimum of ⅛-inch per foot to facilitate efficient water removal to an appropriate outfall. Flap gates or other approved methods should be employed at all free outfalls to reduce the potential for animal access and reverse flow in the system. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 12 Retaining wall backfill should consist of approved low-volume-change (LVC) and essentially-granular materials free from organic matter and debris. Essentially-granular soils offer better stacking characteristics and are less prone to movements associated with freezing through the face of the walls than finer-grained materials. Materials consistent with Colorado Department of Transportation (CDOT) Class 6 or 7 aggregate base course or Class I structure backfill could be used as retaining wall backfill. Cobble-sized materials should not be used as retaining wall backfill. Retaining wall backfill should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. The moisture content of the backfill soils should be adjusted to within ±2% of standard Proctor optimum moisture content at the time of compaction. Excessive lateral stresses can be imposed on retaining walls during backfilling when using heavier mechanical compaction equipment. We recommend compaction of retaining wall backfill be completed using light mechanical or hand compaction equipment. For design of retaining walls protected from hydrostatic loading and backfilled with select granular fill, we recommend using an angle of internal friction of Φ=30° and active equivalent fluid pressure value of 40 pounds per cubic foot in addition to any surcharge loads. The equivalent fluid pressure value outlined above is based on an active stress distribution analysis in which some rotation of the retaining wall is assumed. The angle of internal friction and equivalent fluid pressure values outlined above do not include a factor of safety. Sloped backfill geometry, surcharge loads on the retained soil side of the walls or point loads developed in the wall backfill can add to the lateral forces on retaining walls. If parking areas are anticipated at the top of site retaining walls, we recommend the walls be designed to include surcharge loads from parked vehicles in these areas. The lateral driving forces on the walls will be resisted through a combination of the sliding friction of the footing foundations and passive earth pressure against the embedded portion of the wall below frost depth. A passive equivalent fluid pressure value of 350 pcf could be used for that portion of the wall extended below frost depth, considered to be 30 inches in this area. A coefficient of friction of 0.45 could be used Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 13 between foundation concrete and the bearing soils to resist sliding. The recommended passive equivalent fluid pressure value and coefficient of friction do not include a factor of safety. Indoor Pool We understand an indoor, in-ground pool will be constructed extending to a maximum depth in the range of approximately 5 to 6 feet below present site grades. Based on the materials encountered in the completed site borings and results of laboratory testing, it is our opinion the lightly-loaded swimming pool could be supported on natural, undisturbed clayey/silty sand and sand and gravel. For design of the pool foundation bearing on natural, undisturbed loose to medium dense clayey/silty sand and sand and gravel, we recommend using a maximum net allowable soil bearing pressure of 1,500 psf. Care should be taken to avoid developing unbalanced hydrostatic loads on the pool walls and pool bottom. Pressure relief valves could be considered to avoid developing uplift and excessive horizontal hydrostatic loads. For design of the below-grade pool walls protected from unilateral hydrostatic loading, we recommend using an active equivalent fluid pressure value of 40 pounds per cubic foot. Some rotation of the pool walls must occur to develop the active earth pressure state. That rotation can result in cracking of the walls typically in between corners and other restrained points. The amount of deflection of the top of the wall required to develop the “active” state can be estimated at 0.5% times the height of the wall. An equivalent fluid pressure value of 60 pounds per cubic foot could be used for restrained conditions. Variables that affect active lateral earth pressures include but are not limited to the swell potential of the backfill soils, backfill compaction and geometry, wetting of the backfill soils, surcharge loads and point loads developed in the backfill materials. The recommended equivalent fluid pressure values do not include a factor of safety or an allowance for hydrostatic loading. Use of expansive soil backfill, excessive compaction of the wall backfill or surcharge loads placed adjacent to the pool walls can add to the lateral earth pressures causing the equivalent fluid pressure values used in design to be exceeded. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 14 If backfill is required adjacent to any below-grade pool walls, we recommend those materials consist of approved low-volume change (LVC) soils free from organic matter, debris and other objectionable materials. We understand pea gravel is typically used as pool wall backfill due to the limited area that backfill will extend and inability to access these areas with compaction equipment. If site clayey/silty sand and sand and gravel soils will be used as backfill adjacent to the pool and access with compaction equipment is possible, backfill soils should be placed in loose lifts not to exceed 9 inches thick, adjusted to in moisture and compacted as outlined in the “Demolition and Site Development” section of this report. Cobble-sized materials should not be used as backfill adjacent to pool walls. Excessive lateral stresses can be imposed on below grade walls when using heavier mechanical compaction equipment. We recommend compaction of unbalanced pool wall backfill soils be completed using light mechanical or hand compaction equipment. The essentially-granular site clayey/silty sand and sand and gravel soils would be particularly susceptible to caving and sloughing, therefore excavation of vertical pool walls may be difficult or impossible. In addition, loose clayey/silty sand and sand and gravel soils were encountered near-surface in the completed site borings and may be encountered in the pool excavation. The site soils would be expected to be loose near- surface and could be easily disturbed by the construction activities. Care should be taken at the time of construction to avoid disturbing the foundation bearing subgrade soils and the need for corrective action. Materials which are loosened or disturbed by the construction activities or materials which become dry and desiccated or wet and softened should be removed and replaced or reworked in place prior to placement of pool concrete. We estimate the long-term total and differential settlement of the pool constructed as outlined above would be less than 1 inch. Pavements Pavement subgrades should be develop as outlined in the “Demolition and Site Development” portion of this report. Care should be taken to avoid disturbing the reconditioned subgrade soils prior to placement of site pavements and exterior flatwork. In addition, efforts to maintain the proper moisture content in the subgrade soils should Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 15 be made. If subgrade soils are disturbed or allowed to dry out or become elevated in moisture content, those materials should be reworked in place or removed and replaced prior to paving or concrete placement. We anticipate the site drive and parking areas will be surfaced with asphaltic concrete and/or Portland cement concrete (PCC). The pavement subgrades are expected to consist of reconditioned clayey/silty sand and sand and gravel. The clayey/silty sand and sand and gravel soils classify as A-2-4 and A-4 soils in accordance with the American Association of State and Highway Transportation Officials (AASHTO) classification system and would be subject to moderate remolded shear strength. A resistance value (R-value) of 20 was estimated for the clayey/silty sand subgrade soils and used in the pavement section design. Traffic loading on the site pavements is expected to consist of areas of low volumes of automobiles and light trucks, as well as areas receiving heavier trash and delivery truck traffic. Equivalent 18-kip single axle loads (ESAL’s) were estimated for the quantity of site traffic anticipated. Two (2) general pavement design categories are outlined below in Table I. Standard duty pavements could be considered in automobile drive and parking areas. Heavy duty pavements should be considered for access drives and other areas of the site expected to receive heavy trash and delivery truck traffic. Thicker pavements sections may be appropriate in some areas. We would be happy to complete a pavement section design based on the actual type and quantity of heavy truck traffic anticipated to utilize site pavements. Proofrolling of the pavement subgrades should be completed to help identify unstable areas. Areas which pump or deform excessively should be stabilized prior to surfacing. Depending on the in-place moisture content of the subgrade soils immediately prior to paving, the time of year when construction occurs and other hydrologic conditions, stabilization of the subgrade soils may become necessary to develop a suitable paving platform. Isolated areas of subgrade instability can be mended on a case-by-case basis. If overall instability of the subgrade soils is observed at the time of proofrolling, chemical stabilization of the subgrade soils could be considered to develop a suitable paving platform. If required, we recommend consideration be given to stabilization of the pavement subgrades with Class C fly ash. With the increase in support strength developed by the fly ash stabilization procedures, it is our opinion some credit for the stabilized zone could be included in the pavement section design, reducing the required Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 16 thickness of overlying asphaltic concrete and aggregate base course. Chemical stabilization can also eliminate some of the uncertainty associated with attempting to pave during periods of inclement weather. Pavement section design options incorporating some structural credit for the chemically-stabilized subgrade soils are outlined below in Table 1. TABLE 1 – PAVEMENT SECTION DESIGN Standard Duty Heavy Duty Option A – Composite Asphaltic Concrete (Grading S or SX) Aggregate Base (Class 5 or 6) 4” 6” 5” 8” Option B – Composite on Stabilized Subgrade Asphaltic Concrete (Grading S or SX) Aggregate Base (Class 5 or 6) Fly Ash Stabilized Subgrade 3” 4” 12” 4” 6” 12” Option C - Portland Cement Concrete Pavement PCCP 5” 6” Asphaltic concrete should consist of a bituminous plant mix composed of a mixture of aggregate, filler, binders and additives (if required) meeting the design requirements of the City of Fort Collins. Aggregate used in the asphaltic concrete should meet specific gradation requirements such as Colorado Department of Transportation (CDOT) grading S (¾-inch minus) or SX (½-inch minus) specifications. Hot mix asphalt designed using “Superpave” criteria should be compacted to within 92 to 96% of the materials Maximum Theoretical Density. Aggregate base should be consistent with CDOT requirements for Class 5 or Class 6 aggregate base, placed in loose lifts not to exceed 9 inches thick and compacted to at least 95% of the materials standard Proctor maximum dry density. If chemical stabilization procedures will be completed, we recommend the addition of 12% Class ‘C’ fly ash based on component dry unit weights. A 12-inch thick stabilized zone should be constructed by thoroughly blending the fly ash with the in-place subgrade soils. Some “fluffing” of the finish subgrade level should be expected with the stabilization procedures. The blended materials should be adjusted in moisture content to within the range of ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the material’s standard Proctor maximum dry density within two (2) hours of fly ash addition. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 17 For areas subjected to truck turning movements and/or concentrated and repetitive loading such as dumpster or truck parking and loading areas, we recommend consideration be given to the use of Portland cement concrete pavement with a minimum thickness of 6 inches. The concrete used for site pavements should be air entrained and have a minimum 28-day compressive strength of 4,200 psi. Woven wire mesh or fiber entrained concrete should be considered to help in the control of shrinkage cracking. Areas of the site expected to receive higher volumes of heavy truck traffic may require thicker pavement sections. We would be happy to complete a pavement section design based on the actual type and quantity of heavy truck traffic anticipated. The proposed pavement section designs do not include an allowance for excessive loading conditions imposed by heavy construction vehicles or equipment. Heavily loaded concrete or other building material trucks and construction equipment can cause some localized distress to site pavements. The recommended pavement sections are minimums and periodic maintenance efforts should be expected. A preventative maintenance program can help increase the service life of site pavements. Corrosive Soil Characteristics We measured the soluble sulfate concentration of two (2) representative samples of the subsoils which will likely be in contact with structural concrete. The sulfate concentrations measured in the samples fell within the range of 0 to 150 parts per million. ACI rates the measured concentrations as being a ‘negligible’ to risk of concrete sulfate attack; therefore Type I cement should be suitable for concrete members on and below grade. As an added precaution, Type I/II Portland cement could be considered for additional sulfate resistance of construction concrete. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. Drainage Positive drainage is imperative for satisfactory long-term performance of the proposed building, trash enclosure, gazebo and other associated site improvements. We recommend positive drainage be developed away from the structures during construction Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 18 and maintained throughout the life of the site improvements, with twelve (12) inches of fall in the first 10 feet away from the buildings, where possible. Shallower slopes could be considered in hardscape areas. In the event that some settlement of the building backfill soils occurs and/or poor or negative drainage develops over time, the original grade and associated positive drainage outlined above should be immediately restored. Care should be taken in the planning of landscaping to avoid features which could result in the fluctuation of the moisture content of the foundation bearing and flatwork and pavement subgrade soils. We recommend watering systems be placed a minimum of 5 feet away from the perimeter of the site structure and be designed to discharge away from all site improvements. Gutter systems should be considered to help reduce the potential for water ponding adjacent to the structures, with the gutter downspouts, roof drains or scuppers extended to discharge a minimum of 5 feet away from structural, flatwork and pavement elements. Water which is allowed to pond adjacent to site improvements can result in unsatisfactory performance of those improvements over time. LIMITATIONS This report was prepared based upon the data obtained from the completed site exploration, laboratory testing, engineering analysis and any other information discussed. The completed borings provide an indication of subsurface conditions at the boring locations only. Variations in subsurface conditions can occur in relatively short distances away from the borings. This report does not reflect any variations which may occur across the site or away from the borings. If variations in the subsurface conditions anticipated become evident, the geotechnical engineer should be notified immediately so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any biological or environmental assessment of the site or identification or prevention of pollutants or hazardous materials or conditions. Other studies should be completed if concerns over the potential of such contamination or pollution exist. Geotechnical Subsurface Exploration Report Staybridge Hotel - Lot 1, Baldwin Minor Subdivision 301 East Lincoln Avenue, Fort Collins, Colorado Soilogic # 16-1213 19 The geotechnical engineer should be retained to review the plans and specifications so that comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. The geotechnical engineer should also be retained to provide testing and observation services during construction to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with the generally accepted standard of care for the profession. No warranties express or implied, are made. The conclusions and recommendations contained in this report should not be considered valid in the event that any changes in the nature, design or location of the project as outlined in this report are planned, unless those changes are reviewed and the conclusions of this report modified and verified in writing by the geotechnical engineer. LOG OF BORING B-1 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) - SC CLAYEY SAND 1 dark brown, rust - medium dense 2 - 3 CS 15 0.9 112.0 N/A - - NL NP 8.3% - 4 - 5 CS 31 1.2 110.9 N/A - - - - - - 6 - 7 - SM SAND with varying amouts 8 SP-SM of SILT and GRAVEL - brown, rust 9 medium dense to very dense - 10 SS 50/11" 1.6 - N/A - - - - - - 11 - 12 - 13 - 14 - 15 SS 50/7" 11.6 - N/A - - - - - - BOTTOM OF BORING @ 15.5' 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL Atterberg Limits LOG OF BORING B-2 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 4" VEGETATION & TOPSOIL - 1 - 2 - SC-SM CLAYEY to SILTY SAND 3 dark brown, brown, rust - loose 4 - 5 CS 9 18.0 102.8 N/A None <500 NL NP 54.6% - 6 - 7 - 8 - 9 - SM SAND with varying amouts 10 CS 50/9" 2.4 111.9 N/A - - - - - SP-SM of SILT and GRAVEL - brown, rust 11 medium dense to dense - 12 - 13 - 14 - 15 CS 24 8.1 95.8 N/A - - - - - BOTTOM OF BORING @ 15.0' - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-3 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) - SC CLAYEY SAND with GRAVEL 1 dark brown, rust - 2 - 3 - 4 - 5 CS 9 20.7 108.1 N/A None <500 - - - - 6 - 7 - 8 SM SAND with varying amouts - SP-SM of SILT and GRAVEL 9 dark brown, brown, rust - loose to medium dense 10 SS 10 3.3 - N/A - - - - - - 11 - 12 - 13 - 14 - 15 SS 19 8.1 - N/A - - - - - - BOTTOM OF BORING @ 15.5' 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-4 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 4" VEGETATION & TOPSOIL - 1 - 2 - 3 CS 45 1.6 = N/A - - - - - - 4 - 5 SS 50/11" 2.4 = N/A - - NL NP 11.1% - 6 - SM SAND with varying amouts 7 SP-SM of SILT and GRAVEL - brown, rust 8 medium dense to very dense - 9 - 10 SS 31 2.5 - N/A - - - - - - 11 - 12 - 13 - 14 - 15 SS 34 7.8 - N/A - - - - - - BOTTOM OF BORING @ 15.5' 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-5 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) SC CLAYEY SAND with GRAVEL - dark brown, brown, rust 1 - 2 - 3 CS 24 0.8 128.9 N/A - - - - - - 4 - 5 SS 39 1.3 - N/A - - - - 8.8% - 6 - SM SAND with varying amouts 7 SP-SM of SILT, GRAVEL and COBBLES - brown, rust 8 medium dense to very dense - 9 - 10 SS 27 2.6 - N/A - - - - - - 11 - 12 - 13 - 14 - 15 SS 50/10" 9.5 - N/A - - - - - - BOTTOM OF BORING @ 15.5' 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-6 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) PROBABLE EXISTING FILL MATERIAL; - SC-SM SILTY to CLAYEY SAND with GRAVEL 1 brown, rust - loose 2 - SC CLAYEY SAND 3 CS 8 13.9 106.6 N/A None <500 NL NP 46.4% dark brown, brown - loose 4 - 5 CS 29 0.9 - N/A - - - - - - 6 SM SAND with varying amouts - SP-SM of SILT and GRAVEL 7 brown, rust - medium dense 8 - 9 - 10 SS 13 2.2 - N/A - - - - - - BOTTOM OF BORING @ 10.5' 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-7 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 2.5" ASPHALT PAVEMENT - 1 - 2 SC CLAYEY SAND with GRAVEL - brown, rust 3 CS 25 5.6 106.1 N/A None <500 - - - medium dense - 4 - 5 CS 27 6.4 107.8 N/A None <500 NL NP 32.8% - 6 - SM SAND with varying amouts 7 SP-SM of SILT and GRAVEL - brown, rust 8 very dense - 9 - 10 SS 50/11" 1.6 - N/A - - - - - - BOTTOM OF BORING @ 10.5' 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-8 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) CLAYEY SAND with GRAVEL - dark brown, brown 1 - 2 - 3 CS 11 1.9 - N/A - - - - - - 4 - 5 CS 20 0.5 103.9 N/A - - - - - SM SAND with varying amouts - SP-SM of SILT and GRAVEL 6 brown, rust - loose to medium dense 7 - 8 - 9 - 10 SS 23 1.3 - N/A - - - - - - BOTTOM OF BORING @ 10.5' 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO LOG OF BORING B-9 1/1 CME-45 4" CFA Automatic BMc/ZG Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD qu % Swell @ Pressure # 200 Sieve (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 0 - 4" VEGETATION & TOPSOIL - SC CLAYEY SAND with GRAVEL 1 - 2 - 3 CS 29 0.8 - N/A - - - - - - 4 - 5 CS 37 0.6 121.7 N/A - - - - - SM SAND with varying amouts - SP-SM of SILT and GRAVEL 6 brown, rust - medium dense 7 - 8 - 9 - 10 SS 18 2.8 - N/A - - - - - - BOTTOM OF BORING @ 10.5' 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Liquid Limit NL Plasticity Index NP % Passing #200 54.6% Dry Density (pcf) 102.8 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 SWELL/CONSOLIDATION TEST SUMMARY Sample ID: B-2 @ 4' Sample Description: Dark Brown/Brown Clayey Sand (SC) (swell only) Initial Moisture 18.0% Final Moisture 25.6% % Swell @ 500 psf None Swell Pressure (psf) <500 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density (pcf) 108.1 STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 SWELL/CONSOLIDATION TEST SUMMARY Sample ID: B-3 @ 4' Sample Description: Dark Brown/Brown Silty Sand (SM) with Gravel (swell only) Initial Moisture 20.7% Final Moisture 16.9% % Swell @ 500 psf None Swell Pressure (psf) <500 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit NL Plasticity Index NP % Passing #200 46.4% Dry Density (pcf) 106.6 Final Moisture 24.4% % Swell @ 500 psf None Swell Pressure (psf) <500 Sample ID: B-6 @ 2' Sample Description: Dark Brown/Brown Clayey Sand (SC) with Gravel (swell only) Initial Moisture 13.9% STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit - Plasticity Index - % Passing #200 - Dry Density (pcf) 106.1 Final Moisture 14.9% % Swell @ 500 psf None Swell Pressure (psf) <500 Sample ID: B-7 @ 2' Sample Description: Dark Brown/Brown/Rust Clayey Sand (SC) with Gravel (swell only) Initial Moisture 5.6% STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) Liquid Limit NL Plasticity Index NP % Passing #200 32.8% Dry Density (pcf) 107.8 Final Moisture 16.6% % Swell @ 500 psf None Swell Pressure (psf) <500 Sample ID: B-7 @ 4' Sample Description: Dark Brown/Brown Clayey Sand (SC) with Gravel (swell only) Initial Moisture 6.4% STAYBRIDGE HOTEL 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 SWELL/CONSOLIDATION TEST SUMMARY -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 10 100 1000 10000 100000 --------- Applied Load (psf) UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Clean Gravels Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF Fines classify as ML or MH GM Silty gravelF,G, H Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H Clean Sands Cu ! 6 and 1 " Cc " 3E SW Well graded sandI Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI Fines classify as ML or MH SM Silty sandG,H,I Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I Silts and Clays PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Liquid limit less than 50 Inorganic PI < 4 or plots below “A” lineJ ML SiltK,L,M Liquid limit - oven dried Organic clayK,L,M,N Fine-Grained Soils 50% or more passes the No. 200 sieve Organic Liquid limit - not dried < 0.75 OL Organic siltK,L,M,O Inorganic PI plots on or above “A” line CH Fat clayK,L,M Silts and Clays Liquid limit 50 or more PI plots below “A” line MH Elastic siltK,L,M Organic Liquid limit - oven dried Organic clayK,L,M,P Liquid limit - not dried < 0.75 OH Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well graded sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1⅜" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger CS: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D. California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the “Standard Penetration” or “N-value”. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK (CB) Blows/Ft. (SS) Blows/Ft. Consistency (CB) Blows/Ft. (SS) Blows/Ft. Relative Density (CB) Blows/Ft. (SS) Blows/Ft. Consistency < 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered 3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm 6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard 11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard 19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard > 36 > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Terms of Other Constituents Percent of Dry Weight Major Component of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Terms of Other Constituents Percent of Dry Weight Term Plasticity Index Trace With Modifiers < 5 5 – 12 > 12 Non-plastic Low Medium High 0 1-10 11-30 30+ F If soil contains ! 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains ! 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ! 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains ! 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ! 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling None Finish Date 8/24/2016 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 2 Days After Drilling Dci @ 6.0' USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling None Finish Date 8/24/2016 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 2 Days After Drilling B'filled USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling None Finish Date 8/24/2016 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 2 Days After Drilling B'filled USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling None Finish Date 8/24/2016 Hammer Type: After Drilling None Surface Elev. - Field Personnel: 2 Days After Drilling B'filled USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling 12.0' Finish Date 8/24/2016 Hammer Type: After Drilling Dci @ 6.0' Surface Elev. - Field Personnel: 2 Days After Drilling B'filled USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling 11.0' Finish Date 8/24/2016 Hammer Type: After Drilling Dci @ 7.5' Surface Elev. - Field Personnel: 2 Days After Drilling Dci @ 7.0' USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling 11.0' Finish Date 8/24/2016 Hammer Type: After Drilling 11.0' Surface Elev. - Field Personnel: 2 Days After Drilling 10.0' USCS Sampler Atterberg Limits Project # 16-1213 September 2016 Sheet Drilling Rig: Water Depth Information Start Date 8/24/2016 Auger Type: During Drilling 12.5' Finish Date 8/24/2016 Hammer Type: After Drilling 12.5' Surface Elev. - Field Personnel: 2 Days After Drilling 12.0' USCS Sampler Atterberg Limits B'filled During Drilling After Drilling Sheet Start Date Finish Date 2 Days After Drilling Water Depth Information 8/24/2016 13.0' 301 E. LINCOLN AVENUE, FORT COLLINS, COLORADO Project # 16-1213 September 2016 Sampler USCS Surface Elev. Dci @ 10' Auger Type: Drilling Rig: Hammer Type: Field Personnel: 8/24/2016 -