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Home My WebLink AboutTHE HUB ON CAMPUS - PDP - PDP160038 - SUBMITTAL DOCUMENTS - ROUND 3 - DRAINAGE REPORTDRAINAGE REPORT: THE HUB ON CAMPUS – FORT COLLINS 1415 W. Elizabeth Street Fort Collins, CO Prepared by: Kimley-Horn and Associates, Inc. 1001 Warrenville Road, Suite 350 Lisle, IL 60532 Contact: Lesley Netzer Prepared on: 02/21/2017 Revised on: 05/30/2017 The Hub on Campus – Fort Collins, CO May 2017 Page 1 TABLE OF CONTENTS Project Description 02 Storm Sewer Design Summary 03 Water Quality and BMP Selection 03 Conclusion 04 EXHIBITS Exhibit 1. FEMA Floodplain Map Exhibit 2. NRCS Soils Map Exhibit 3. Geotech Report Exhibit 4. Existing Drainage Plan Exhibit 5. Proposed Drainage Plan Exhibit 6. Storm Sewer Calculations The Hub on Campus – Fort Collins, CO May 2017 Page 2 1. PROJECT DESCRIPTION Kimley-Horn and Associates, Inc., serves as the engineering consultant for CORE Fort Collins 1415 Elizabeth, LLC. They are proposing to construct a a mixed-use building, consisting of both multi- family residential as well as retail space along W. Elizabeth Street. In addition, a parking garage is proposed southwest of the main structure. The site is located at 1415 W. Elizabeth Street in Fort Collins, Colorado (Larimer County). The site work on the approximate 1.93 acre parcel includes demolition, grading, stormwater management, water, sanitary sewer, paving installation, and landscape improvements. The “Urban Drainage and Flood Control District Manual” Volumes 1, 2, and 3 (UDFCD Manual) and the Fort Collins Amendments to the UDFCD, with latest revisions, were used to prepare the stormwater approach and calculations. 1.1. Pre Development Conditions The approximate 1.93 acre project consists of three separate parcels, currently developed as a restaurant, brewery, and associated parking lot. The site is bound to the east and south by multi- family residential buildings and to the west by a recently developed commercial/retail center with frontage along W. Elizabeth Street. The property is located within City of Fort Collins Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map Number 08069C0978G, revised May 2, 2012 and is designated as an area outside the 500-year floodplain. The FEMA Firmette is included in Exhibit 1. An NRCS soils map is included in Exhibit 2, which indicates that the majority of the site consists of Altvan-Satanta loams with hydrologic soil group rating B. Although, based on the geotechnical report prepared by Earth Engineering Consultants, LLC dated September 20, 2016 the existing soils consist of cohesive sandy lean clay containing intermittent sand and gravel layers which extended to the bedrock about 10 ½-12 feet below the surface. The full geotechnical report is included in Exhibit 3. Currently developed, the site is approximately 87.5% impervious. Stormwater drainage for the site discharges through various inlets throughout the site, which is ultimately routed to a storm sewer in W. Elizabeth Street. The site is part of the Old Town Drainage Basin, stormwater runoff flows to Spring Creek, ultimately tributary to the Poudre River. See Exhibit 4 for the Existing Drainage Plan. 1.2. Post Development Conditions The proposed development includes a mixed-use building, consisting of both multi-family residential as well as retail space along W. Elizabeth Street. In addition, a parking garage is proposed southwest of the main structure. The proposed impervious percentage is 74.1%, a net decrease in impervious area of approximately 0.26 acres (11,325 SF). The Hub on Campus – Fort Collins, CO May 2017 Page 3 Runoff from the site will primarily be directed to the proposed LID techniques located throughout the site: • Roof drains for the mixed use building will discharge onto the surface, directing flows onto the paver systems as well as a sand filter on the east side of the site • Roof drains from the parking garage will discharge into a bioswale along the north side of the garage • Interior floors of the parking garage will be treated by a sand/oil interceptor prior to entering the sanitary sewer. As in existing conditions, the ultimate outfall for the storm sewer system will be the 15-inch sewer in Elizabeth Street ROW. A proposed Drainage Plan has been provided in Exhibit 5. 2. STORM SEWER DESIGN SUMMARY 2.1. Storm Sewer Design A large amount of offsite flow is routed through the site from south to north. In the proposed condition, the storm sewer is routed around the The Hub on Campus Development, maintaining the existing storm sewer sizes and slopes. A complete drainage study on the capacity of the storm sewer system for these offsite flows was not performed. As mentioned, the impervious percentage has been reduced, reducing flows to the exiting storm sewer system. Hydraulic calculations were performed using Hydraflow for a minor storm event (2-10 year storm), in the absence of offsite flows from the south. Runoff amounts were calculated per Volume 1, Chapter 4 of the Fort Collins Amendments to the UDFCD. A weighted runoff coefficient for each drainage area was calculated and a minimum time of concentration of 5 minutes was assumed for each drainage area. Minor and major runoff coefficients that were used in the “Rational Method” analysis of the flow can be found on the Proposed Drainage Plan in Exhibit 5. Storm Sewer Calculations are included in Exhibit 6. 3. WATER QUALITY AND BMP SELECTION The proposed development will be required to meet all applicable water quality design criteria referenced in Volume 3, Chapter 3.0 of the UDFCD Manual. The manual recommends a four-step process for treating the required water quality volume as shown below. 1. Employ runoff reduction practices - The redevelopment on an urban site provides limited opportunities to employ runoff reduction practices. The site has been developed to install landscaping, pervious pavers, and bioswales wherever pavement (or building) is not required for the functionality of the site. 2. Implement BMPs that provide a water quality capture volume with a slow release – The majority of site will be treated by “Permeable Interlocking Concrete Pavement” (Pervious Pavers) and Bioswales/Sand Filters per Volume 3, Chapter 4 of the UDFCD Manual. The Hub on Campus – Fort Collins, CO May 2017 Page 4 3. Stabilize Drainage Ways – Not applicable. This development is not adjacent to a stream, nor does it directly impact the downstream water body (Spring Creek). 4. Implement site specific and other source control BMPs –Trash and recycling containers will be provided on site. Vehicular parking will be located in garages to reduce potential for contamination discharges. The water quality requirements will be met by utilizing only LID tecniques. In total, runoff from 97.2% of the proposed impervious surfaces will pass through an LID technique prior to discharging from the site. • One bioswale is proposed, which maintains a 10:1 ratio of tributary area to swale area. • Four locations of pervious pavement are proposed, which maintain a 3:1 ratio of tributary area pavers area. • One sand filter area is proposed, which maintaings a 25:1 ration of tributary are to filter area The proposed drainage plan depicts the exact location and drainage areas of each of the LID techniques in Exhibit 5. Exhibit 1 – FEMA Floodplain Map Exhibit 2 – NRCS Soils Map Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/14/2016 Page 1 of 4 4491420 4491440 4491460 4491480 4491500 4491520 4491540 4491420 4491440 4491460 4491480 4491500 4491520 4491540 491200 491220 491240 491260 491280 491300 491320 491340 491360 491380 491200 491220 491240 491260 491280 491300 491320 491340 491360 491380 40° 34' 28'' N 105° 6' 14'' W 40° 34' 28'' N 105° 6' 6'' W 40° 34' 24'' N 105° 6' 14'' W 40° 34' 24'' N 105° 6' 6'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 45 90 180 270 Feet 0 10 20 40 60 Meters Map Scale: 1:927 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes B 2.0 95.7% 76 Nunn clay loam, wet, 1 to 3 percent slopes C 0.1 4.3% Totals for Area of Interest 2.1 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/14/2016 Page 3 of 4 Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/14/2016 Page 4 of 4 Exhibit 3 – Geotech Report PRELIMINARY GEOTECHNICAL EXPLORATION REPORT PROPOSED MIXED USE DEVELOPMENT/STUDENT HOUSING PROJECT 1415 – 1427 WEST ELIZABETH STREET FORT COLLINS, COLORADO EEC PROJECT NO. 1162060 Prepared for: Core Spaces 2234 W. North Avenue Chicago, Illinois 60647 Attn: Mr. Chad Matesi (chadm@corespaces.com) Prepared by: Earth Engineering Consultants, LLC 4396 Greenfield Drive Windsor, Colorado 80550 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 September 20, 2016 Core Spaces 2234 W. North Avenue Chicago, Illinois 60647 Attn: Mr. Chad Matesi (chadm@corespaces.com) Re: Preliminary Geotechnical Exploration Report Proposed Mixed Use Development/Student Housing Project 1415 – 1427 West Elizabeth Street Fort Collins, Colorado EEC Project No. 1162060 Mr. Matesi: Enclosed, herewith, are the results of the preliminary geotechnical subsurface exploration completed by Earth Engineering Consultants, LLC (EEC) for the referenced project. For this exploration, EEC personnel completed five (5) soil borings at pre-selected locations within the proposed development/student housing area at 1415 – 1427 West Elizabeth Street in Fort Collins, Colorado. The test borings were positioned at locations accessible to our drilling equipment around the existing buildings which currently occupy a portion of the site. The test borings were extended to approximate depths of 25 to 30 feet below present site grades. This study was completed in general accordance with our proposal dated June 6, 2016. In summary, the subsurface soils encountered beneath the surficial pavement section generally consisted of cohesive sandy lean clay containing intermittent sand and gravel zones/layers with depth, which extended to the bedrock formation below. Layered sandstone/siltstone/claystone bedrock was encountered in the borings at depths of approximately 10½ to 12 feet below existing site grades and extended to the maximum depths explored, approximately 30 feet. Groundwater was initially encountered during the field exploration at approximate depths of 6½ to 11 feet below existing site grades. Based on the subsurface conditions encountered in the test borings, as well as the anticipated maximum loading conditions, we believe the proposed multi-story structure could be supported on foundations extending to bear on the moderately hard bedrock strata. Those foundations could include drilled piers extending into the bedrock formation assuming a non-basement PRELIMINARY GEOTECHNICAL EXPLORATION REPORT PROPOSED MIXED USE DEVELOPMENT/STUDENT HOUSING PROJECT 1415 – 1427 WEST ELIZABETH STREET FORT COLLINS, COLORADO EEC PROJECT NO. 1162060 September 20, 2016 INTRODUCTION The preliminary geotechnical subsurface exploration for a proposed multi-level, mixed use development/student housing project for 1415 through 1427 West Elizabeth Street in Fort Collins, Colorado, has been completed. For this exploration, Earth Engineering Consultants, LLC (EEC) advanced five (5) soil borings to depths of approximately 25 to 30 feet below present site grades at pre-selected locations on the proposed development property to develop data on existing subsurface conditions. This exploration was completed in general accordance with our proposal dated June 6, 2016. We understand the mixed use/student housing building as presently envisioned will include 3 to 5- stories above grade and, if feasible, 1½ levels of below grade parking. The building footprint would occupy the majority of the site. The existing C.B. & Pots Restaurant and Brewhouse buildings, along with the mature trees on the site would be demolished/removed prior to construction of the new structure. The new building below grade parking will extend to depths on the order of 10 to 15 feet below the existing site surface grades. Foundation loads for the new structure are estimated to be moderate to high with maximum continuous wall loads in the range of 1 to 5 kips per linear foot (KLF) and maximum column loads potentially on the order of 100 to 500 kips. Floor loads are expected to be light to moderate. Small grade changes are expected to develop final site grades outside of the basement area. The purpose of this report is to describe the subsurface conditions encountered in the test borings, analyze and evaluate the test data and provide preliminary geotechnical recommendations concerning design and construction of foundations and support of floor slabs for the new building. Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 2 EXPLORATION AND TESTING PROCEDURES The boring locations were established in the field by representatives from EEC by pacing and estimating angles from identifiable site features. Those approximate boring locations are indicated on the attached boring location diagram. The locations of the borings should be considered accurate only to the degree implied by the methods used to make the field measurements. Photographs of the site taken at the time of drilling are included with this report. The test borings were completed using a truck mounted, CME-75 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers. Samples of the subsurface materials encountered were obtained using split barrel and California barrel sampling procedures in general accordance with ASTM Specifications D1586 and D3550, respectively. In the split barrel and California barrel sampling procedures, standard sampling spoons are driven into the ground with a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split barrel and California barrel samplers is recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. In the California barrel sampling procedure, relatively intact samples are obtained in removable brass liners. All samples obtained in the field were sealed and returned to our laboratory for further examination, classification, and testing. Laboratory moisture content tests were completed on each of the recovered samples. Atterberg limits and washed sieve analysis tests were completed on selected samples to evaluate the quantity and plasticity of fines in the subgrade samples. Swell/consolidation tests were completed on selected samples to evaluate the potential for the subgrade materials to change volume with variation in moisture and load. Soluble sulfate tests were completed on selected samples to evaluate potential sulfate attack on site-cast concrete. Results of the outlined tests are indicated on the attached boring logs and summary sheets. As part of the testing program, all samples were examined in the laboratory and classified in general accordance with the attached General Notes and the Unified Soil Classification System, based on the soil’s texture and plasticity. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs and a brief description of that classification system is included with Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 3 this report. Classification of the bedrock was based on visual and tactual observation of disturbed samples and auger cuttings. Coring and/or petrographic analysis may reveal other rock types. SITE AND SUBSURFACE CONDITIONS The area for the proposed building currently includes existing buildings (i.e. The C.B. & Pots Restaurant and Brewhouse), with the remaining lot consisting of asphalt paved parking areas. A Google Earth aerial photo of the site indicating current site layout and approximate boring locations in relation to existing site features is included with this report. The site is relatively flat, with approximately 2 to 3 feet (+/-) of relief across the site. Based on results of the field borings and laboratory testing, subsurface conditions can be generalized as follows. The subsurface soils encountered beneath surficial pavement sections generally consisted of cohesive sandy lean clay with sand layers and interbedded fine to coarse granular strata with depth. The cohesive soils were medium stiff to stiff, and exhibited low expansive characteristics with slight compressible/consolidation characteristics. Layered sandstone/siltstone/claystone bedrock was encountered beneath the overburden soils within the borings, at depths of approximately 10½ to 12 feet below existing surface grades and extended to the maximum depths explored, approximately 25 to 30 feet. The bedrock formation was weathered nearer surface; however, became less weathered and more competent with depth. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil and bedrock types. In-situ, the transition of materials may be gradual and indistinct. GROUNDWATER CONDITIONS Observations were made while drilling and after completion of the borings to detect the presence and depth to hydrostatic groundwater. At the time of drilling, free water was observed across the site at approximate depths of 6½ to 11 feet below existing site grades. The borings were backfilled upon completion of the drilling operations; subsequent groundwater measurements were not obtained. Fluctuations in groundwater levels can occur over time depending on variations in hydrologic conditions, irrigation demands on and/or adjacent to the site and other conditions not apparent at the Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 4 time of this report. Longer term monitoring of water levels in cased wells, which are sealed from the influence of surface water would be required to more accurately evaluate depth to groundwater and fluctuations in groundwater levels at the site. We have typically noted deepest groundwater levels in late winter and shallowest groundwater levels in mid to late summer. Zones of perched and/or trapped water can be encountered at times throughout the year in more permeable zones in the subgrade soils. Perched water is commonly observed in subgrade soils immediately above lower permeability bedrock. ANALYSIS AND RECOMMENDATIONS: General Considerations The subject site is generally overlain by approximately 10 to 12 feet of stratified cohesive clay soils with sand and gravel zones which extend to the bedrock below. A portion of the cohesive subsoils have a tendency to consolidate when inundated with water and subjected to increased loads. These soils would also show instability and strength loss when wetted and/or subjected to the expected building loads. Foundation support will need to extend to the underlying bedrock through the use of deep foundations (drilled piers), an over excavation and backfill procedure or extending footing foundations to bear directly on the underlying bedrock. Free groundwater was observed at depths of approximately 6½ to 11 feet below existing surface grades at the time of the field exploration. Construction of a “perimeter” dewatering system should be expected if below grade parking will be developed on the site. Use of a perimeter barrier system such as secant piles could be considered to combine support of the structure with a groundwater barrier system for the below grade parking. Site Preparation We understand the existing structures on the site along with any associated site improvements will be demolished/removed from the site prior to the new building construction. In addition, all existing vegetation, tree root growth from the existing deciduous trees within the site improvement areas, topsoil, and any uncontrolled fill material that may be encountered during the excavation phases, should be removed from improvement and/or fill areas on the site. Demolition of the existing Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 5 structures, concrete sidewalks, pavement and other miscellaneous features should include complete removal of all concrete, pavement and/or debris within the proposed construction area. Site preparation should include removal of any loose backfill found adjacent to the existing site structures/improvements. All materials derived from the demolition of the existing building, pavements, sidewalks or other site improvements should be removed from the site and not be allowed for use in any on-site fills. Although final site grades were not available at the time of this report, based on our understanding of the proposed development, we would anticipate small amounts of fill material may be necessary outside of the building area to achieve final design grades in the improvement areas. After stripping, completing all cuts, and removing all unacceptable materials/soils, and prior to placement of any fill or site improvements, we recommend the exposed soils be scarified to a minimum depth of 9-inches, adjusted in moisture content to within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the material's standard Proctor maximum dry density as determined in accordance with ASTM Specification D698. Fill soils required for developing the site subgrades, after the initial zone has been prepared or stabilized where necessary, should consist of approved, low-volume-change materials, which are free from organic matter and debris. It is our opinion the on-site cohesive sandy clay soils could be used as general site fill material, provided adequate moisture treatment and compaction procedures are followed. We recommend all fill materials and foundation wall backfill materials, be placed in loose lifts not to exceed 9 inches thick and adjusted in moisture content, +/- 2% for cohesive soils and +/- 3% for cohesionless soils of optimum moisture content, and compacted to at least 98% of the materials maximum dry density as determined in accordance with ASTM Specification D698, the standard Proctor procedure. If the site’s sandy cohesive soils are used as fill material, care will be needed to maintain the recommended moisture content prior to and during construction of overlying improvements. Settlement of the backfill soils should be anticipated with total settlement estimated on the order of 1% of the backfill height. Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade materials. Positive drainage should be developed away from the structure to avoid wetting of Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 6 subgrade materials. Subgrade materials becoming wet subsequent to construction of the site structure can result in unacceptable performance. Foundation Systems – General Considerations For support of the proposed structure, we believe it will be necessary to extend foundation loads to the bedrock formation encountered at depths of approximately 10½ to 12 feet below current ground surface. If the proposed 1½ story below grade component is included in the final design, we expect the below grade excavation would naturally extend to the bedrock formation. However, this design would require an approach to deal with groundwater which was observed at depths of approximately 6½ to 11 feet in the test borings. If the below grade area is eliminated, use of “deep” foundations to extend load to the bedrock would be an acceptable approach. The deep foundations would probably be straight shaft drilled piers although other systems could be considered. In a shallower basement system, over excavation/backfill procedures may be considered. Recommendations for the following systems are provided with this report.  Conventional spread footing foundations supported on the underlying bedrock, and  Straight shaft drilled piers/caissons bearing into the underlying bedrock formation. Other alternative foundation systems could be considered and we would be pleased to provide additional alternatives upon request. Footing Foundations Conventional spread footing foundations could be supported directly on the moderately hard bedrock as outlined above. For design of footing foundations bearing on suitable moderately hard bedrock formation, we recommend using a net allowable total load soil bearing pressure not to exceed 5,000 psf. The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Footings should not be supported within the overburden subsoils. Total load should include full dead and live loads. We estimate the long-term settlement of footing foundations designed and constructed as outlined above would be less than 1-inch. Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 7 Exterior foundations and foundations in unheated areas should be located at least 30-inches below adjacent exterior grade to provide frost protection. We recommend formed continuous footings have a minimum width of 12-inches and isolated column foundations have a minimum width of 24-inches. No unusual problems are anticipated in completing the excavations required for construction of the footing foundations. However, groundwater was observed above the bedrock formation which will require both temporary construction dewatering and permanent dewatering for the completed structure. Care should be taken during construction to thoroughly evaluate the bearing materials to verify that the footing foundations are supported on suitable strength materials. Drilled Piers/Caissons Foundations Based on the subgrade conditions observed in the test borings and on the anticipated foundation loads, we believe the foundation loads could be supported on a grade beam and straight shaft drilled pier/caisson foundation system extending into the underlying bedrock formation. Particular attention will be required in the construction of drilled piers due to the presence of groundwater. For axial compression loads, the drilled piers could be designed using a maximum end bearing pressure of 40,000 pounds per square foot (psf), along with a skin-friction of 4,000 psf for the portion of the pier extended into the underlying firm and/or harder bedrock formation. Straight shaft piers should be drilled a minimum of 10 feet into competent or harder bedrock. Lower allowable bearing values may be appropriate for pier “groupings” depending on the pier diameters and spacing. Pile groups should be evaluated separately. To satisfy forces in the horizontal direction, piers may be designed for lateral loads using a modulus of 50 tons per cubic foot (tcf) for the portion of the pier in native cohesive/granular soils, and 400 tcf in bedrock for a pier diameter of 12 inches. The coefficient of subgrade reaction for varying pier diameters is as follows: Pier Diameter Coefficient of Subgrade Reaction (tons/ft3) Cohesive Soils Bedrock 18 33 267 24 25 200 30 20 160 36 17 133 Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 8 When the lateral capacity of drilled piers is evaluated by the L-Pile (COM 624) computer program, we recommend that internally generated load-deformation (P-Y) curves be used. The following parameters may be used for the design of laterally loaded piers, using the L-Pile (COM 624) computer program: Parameters On-Site Overburden Cohesive Soils Bedrock Unit Weight of Soil (pcf) 120(1) 125(1) Cohesion (psf) 200 5000 Angle of Internal Friction () (degrees) 25 20 Strain Corresponding to ½ Max. Principal Stress Difference 50 0.02 0.015 *Notes: 1) Reduce by 62.4 pcf below the water table Drilling caissons to design depth should be possible with conventional heavy-duty single flight power augers equipped with rock teeth on the majority of the site. However, areas of well-cemented sandstone bedrock lenses may be encountered throughout the site at various depths where specialized drilling equipment and/or rock excavating equipment may be required. Varying zones of cobbles may also be encountered in the granular soil zones above the bedrock. Excavation penetrating the well- cemented sandstone bedrock may require the use of specialized heavy-duty equipment, together with rock augers and/or core barrels. Consideration should be given to obtaining a unit price for difficult caisson excavation in the contract documents for the project. Due to the presence of groundwater at approximate depths of 6½ to 11 feet below site grades, maintaining shafts may be difficult without stabilizing measures. We expect temporary casing will be required to adequately/properly drill and clean piers prior to concrete placement. Groundwater should be removed from each pier hole prior to concrete placement. Pier concrete should be placed immediately after completion of drilling and cleaning. A maximum 3-inch depth of groundwater is acceptable in each pier prior to concrete placement. If pier concrete cannot be placed in dry conditions, a tremie should be used for concrete placement. Due to potential sloughing and raveling, foundation concrete quantities may exceed calculated geometric volumes. Pier concrete with slump in the range of 6 to 8 inches is recommended. Casing used for pier Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 9 construction should be withdrawn in a slow continuous manner maintaining a sufficient head of concrete to prevent infiltration of water or the creation of voids in pier concrete. Foundation excavations should be observed by the geotechnical engineer. A representative of the geotechnical engineer should inspect the bearing surface and pier configuration. If the soil conditions encountered differ from those presented in this report, supplemental recommendations may be required. We estimate the long-term settlement of drilled pier foundations designed and constructed as outlined above would be less than 1-inch. Seismic Site Classification The site soil conditions consist of approximately 10 to 12 feet of overburden soils overlying moderately hard to hard bedrock. For those site conditions, the International Building Code indicates a Seismic Site Classification of C. Lateral Earth Pressures The new retail/student housing development building may be constructed over below grade parking. The below grade walls will be subjected to unbalanced lateral earth pressures. Any site retaining walls or similar structures would also be subject to lateral soil forces. Passive lateral earth pressures may help resist the driving forces for retaining wall or other similar site structures. Active lateral earth pressures could be used for design of structures where some movement of the structure is anticipated, such as retaining walls. The total deflection of structures for design with active earth pressure is estimated to be on the order of one half of one percent of the height of the down slope side of the structure. We recommend at-rest pressures be used for design of structures where rotation of the walls is restrained, including the below grade parking structure walls. Passive pressures and friction between the footing and bearing soils could be used for design of resistance to movement of retaining walls. Coefficient values for backfill with anticipated types of soils for calculation of active, at rest and passive earth pressures are provided in the table below. Equivalent fluid pressure is equal to the Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 10 coefficient times the appropriate soil unit weight. Those coefficient values are based on horizontal backfill with backfill soils consisting of essentially granular materials with a friction angle of a 30 degrees or low volume change cohesive soils. For the at-rest and active earth pressures, slopes down and away from the structure would result in reduced driving forces with slopes up and away from the structures resulting in greater forces on the walls. The passive resistance would be reduced with slopes away from the wall. The top 30-inches of soil on the passive resistance side of walls could be used as a surcharge load; however, it should not be used as a part of the passive resistance value. Frictional resistance is equal to the tangent of the friction angle times the normal force. Soil Type Low Plasticity Cohesive Medium Dense Granular Wet Unit Weight 120 130 Saturated Unit Weight 135 140 Friction Angle () – (assumed) 25° 35° Active Pressure Coefficient 0.40 0.27 At-rest Pressure Coefficient 0.58 0.42 Passive Pressure Coefficient 2.46 3.69 Surcharge loads or point loads placed in the backfill can also create additional loads on below grade walls. Those situations should be designed on an individual basis. The outlined values do not include factors of safety nor allowances for hydrostatic loads and are based on assumed friction angles, which should be verified after potential material sources have been identified. Care should be taken to develop appropriate drainage systems behind below grade walls to eliminate potential for hydrostatic loads developing on the walls. Those systems should be designed as subsequently outlined in this report. Where necessary, appropriate hydrostatic load values should be used for design. Slab-On-Grade Construction Based on the materials observed in the soil borings, it is our opinion at grade level flatwork could be directly supported by the reworked site soils or placed fill soils as outlined under Site Preparation. A granular leveling course could be used, if needed. Under slab vapor barrier should be used at the architect’s discretion. Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 11 Additional on-grade slab design and construction recommendations are as follows:  Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement.  Control joints should be provided in slabs to control the location and extent of cracking.  Trench backfill placed beneath slabs should be compacted in a similar manner as previously described for site fill material.  The concrete slabs should not be constructed on frozen subgrade.  Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended. Perimeter Drainage Systems We understand the below grade parking area, if included in the building design, will extend to a depth of approximately 10 to 15 feet below present surface grades. The subsurface soils encountered in the test borings completed for this project included approximately 10½ to 11 feet of sandy lean clay/layered with sands and gravels which were underlain by weathered bedrock. The test borings encountered groundwater at depths on the order of 6½ to 11 feet below present site grades. However, some fluctuation can occur in groundwater depths depending on variations in hydrologic conditions and other conditions not apparent at the time of this report. At a depth of approximately 10 to 15 feet below existing ground surface, the bottom of the basement walls for the structure are expected to terminate in the weathered bedrock. We expect the structure will be supported on footings or drilled pier foundations extending to the underlying bedrock. With potential infiltration of surface water adjacent to the building and extending the basement walls below current groundwater levels, we anticipate water would accumulate next to the below grade walls and result in hydrostatic loading on those walls and, potentially, infiltration of water into the below grade areas. We suggest a drain system be installed to remove water from the area adjacent to the below grade walls and reduce the likelihood of development of hydrostatic loads on the walls and/or water infiltration into the below grade area or that the walls be designed to resist hydrostatic loads and provisions made to prevent water infiltration. Installation of a drain system would reduce, not eliminate, the potential for infiltration of surface and/or groundwater into the below grade areas and development of hydrostatic loads on structure Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 12 components. Pumps and other components require periodic inspections and maintenance to maintain the system in functioning condition. Additional drainage system design recommendations can be provided when the final decision/development concepts are more defined. Water Soluble Sulfates (SO4) The water soluble sulfate (SO4) testing of the on-site overburden and bedrock materials taken during our subsurface exploration are provided in the table below. TABLE IV - Water Soluble Sulfate Test Results Sample Location Description Soluble Sulfate Content (mg/kg) Soluble Sulfate Content (%) B-1, S-4 at 19' Siltstone/Claystone Bedrock 90 0.01 B-3, S-2 at 4' Sandy Lean Clay 180 0.02 Based on the results as presented in the table above, ACI 318, Section 4.2 indicates the site overburden soils and/or bedrock generally have a low risk of sulfate attack on Portland cement concrete. Therefore, Class 0 and/or Type I/II cement could be used for concrete on and below site grade within the overburden soils and/or bedrock. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. These results are being compared to the following table. Table V - Requirements to Protect Against Damage to Concrete by Sulfate Attack from External Sources of Sulfate Severity of Sulfate exposure Water-soluble sulfate (SO4) in dry soil, percent Water-cement ratio, maximum Cementitious material Requirements Class 0 0.00 to 0.10% 0.45 Class 0 Class 1 0.11 to 0.20% 0.45 Class 1 Class 2 0.21 to 2.00% 0.45 Class 2 Class 3 2.01 of greater 0.45 Class 3 Pavement Subgrade / Pavements We expect the site pavements if incorporated into the final design, will be designated for low traffic volume of automobile and occasional heavier vehicle delivery/trash have truck traffic. We are using an assumed equivalent daily load axle (EDLA) rating of 15 for design of the site pavements for that traffic. Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 13 Proofrolling and recompacting the subgrade is recommended immediately prior to placement of the pavements. Soft or weak areas delineated by the proofrolling operations should be undercut or stabilized in-place to achieve the appropriate subgrade support. Based on the subsurface conditions encountered at the site and the results of the laboratory testing, it is recommended the on-site private drives and parking areas be designed using an R-value of 10. Pumping conditions could develop within a moisture treatment scarification/compactions process of on-site cohesive soils. Subgrade stabilization may be needed to develop a stable subgrade for paving. If needed, stabilization could include incorporating at least 12 percent (by weight) Class C fly ash into the upper 12 inches of subgrade. Recommended pavement sections are provided below in Table VI. If selected, Portland cement concrete should be an exterior pavement design mix with a minimum 28-day compressive strength of 4,000 psi and should be air entrained. Hot bituminous pavement should consist of S-75 or SX-75 with performance graded PG 58-28 binder, compacted to be within the range of 92 to 96% of maximum theoretical specific gravity (Rice). In areas subject to heavier truck loads or truck turning movements, (including trash truck routes and load/unload areas) consideration should be given to use of Portland cement concrete for the pavements. The recommended pavement sections are minimums and periodic maintenance should be expected. Table VI - Recommended Minimum Pavement Sections Heavy Duty Areas 18-kip EDLA 18-kip ESAL’s Reliability Resilient Modulus PSI Loss 15 109,500 85% 3562 psi 2.0 Design Structure Number 3.00 (A) Composite Hot Bituminous Pavement Aggregate Base (Design Structural Number) 5" 8" (3.08) (B) Composite with Fly Ash Treated Subgrade Hot Bituminous Pavement Aggregate Base Fly Ash Treated Subgrade (Design Structure Number) 4" 6" 12" (3.02) (C) PCC (Non-reinforced) 6" Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 14 The collection and diversion of surface drainage away from paved areas is critical to the satisfactory performance of the pavement. Drainage design should provide for the removal of water from paved areas in order to reduce the potential for wetting of the subgrade soils. Other Considerations Positive drainage should be developed away from the structure with a minimum slope of 1-inch per foot for the first 10-feet away from the improvements in landscape areas. Flatter slopes could be used in hardscapes areas although positive drainage should be maintained. Care should be taken in planning of landscaping adjacent to the building and parking and drive areas to avoid features which would pond water adjacent to the pavement, foundations or stemwalls. Placement of plants which require irrigation systems or could result in fluctuations of the moisture content of the subgrade material should be avoided adjacent to site improvements. Excavations into the on-site soils may encounter a variety of conditions. Excavations into the on- site clays above the water table can be expected to stand on relatively steep temporary slopes during construction. However, if excavations extend near or below the water table, caving soils may be encountered. The individual contractor(s) should be made responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards. Depending upon the depth of any lower level construction, a shoring plan will be necessary to protect the adjacent sidewall slopes. The project design team should use the subsurface information provided herein to properly design a mechanism for shoring protection. EEC is available to provide supplemental design criteria or details such as but not limited to secant piles or piers, soldier piers, or a tie-back/bracing concept. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations, which may occur between borings or across the Earth Engineering Consultants, LLC EEC Project No. 1162060 September 20, 2016 Page 15 site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical engineer be retained for testing and observations during earthwork phases to help determine that the design requirements are fulfilled. Site-specific explorations should be completed to develop site- specific recommendations for each of the site buildings. This report has been prepared for the exclusive use for Core Spaces for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. Earth Engineering Consultants, LLC DRILLING AND EXPLORATION DRILLING & SAMPLING SYMBOLS: SS: Split Spoon ‐ 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample ST: Thin‐Walled Tube ‐ 2" O.D., unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler ‐ 2.42" I.D., 3" O.D. unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit = 4", N, B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2‐inch O.D. split spoon, except where noted. 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 Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D‐2488. Coarse Grained Soils have move than 50% of their dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are 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 relative in‐ place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). CONSISTENCY OF FINE‐GRAINED SOILS Unconfined Compressive Strength, Qu, psf Consistency < 500 Very Soft 500 ‐ 1,000 Soft 1,001 ‐ 2,000 Medium 2,001 ‐ 4,000 Stiff 4,001 ‐ 8,000 Very Stiff 8,001 ‐ 16,000 Very Hard RELATIVE DENSITY OF COARSE‐GRAINED SOILS: N‐Blows/ft Relative Density 0‐3 Very Loose 4‐9 Loose 10‐29 Medium Dense 30‐49 Dense 50‐80 Very Dense 80 + Extremely Dense PHYSICAL PROPERTIES OF BEDROCK DEGREE OF WEATHERING: Slight Slight decomposition of parent material on joints. May be color change. Moderate Some decomposition and color change throughout. High Rock highly decomposed, may be extremely broken. Group Symbol Group Name Cu≥4 and 1<Cc≤3 E GW Well-graded gravel F Cu<4 and/or 1>Cc>3 E GP Poorly-graded gravel F Fines classify as ML or MH GM Silty gravel G,H Fines Classify as CL or CH GC Clayey Gravel F,G,H Cu≥6 and 1<Cc≤3 E SW Well-graded sand I Cu<6 and/or 1>Cc>3 E SP Poorly-graded sand I Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I inorganic PI>7 and plots on or above "A" Line CL Lean clay K,L,M PI<4 or plots below "A" Line ML Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,N Liquid Limit - not dried Organic silt K,L,M,O inorganic PI plots on or above "A" Line CH Fat clay K,L,M PI plots below "A" Line MH Elastic Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,P Liquid Limit - not dried Organic silt K,L,M,O Highly organic soils PT Peat (D30)2 D10 x D60 GW-GM well graded gravel with silt NPI≥4 and plots on or above "A" line. GW-GC well-graded gravel with clay OPI≤4 or plots below "A" line. GP-GM poorly-graded gravel with silt PPI plots on or above "A" line. GP-GC poorly-graded gravel with clay QPI plots below "A" line. 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 Earth Engineering Consultants, LLC IIf soil contains >15% gravel, add "with gravel" to group name JIf Atterberg limits plots shaded area, soil is a CL- ML, Silty clay Unified Soil Classification System 1 2 B-1 B-2 B-3 B-4 B-5 Boring Location Diagram 1415 - 1427 West Elizabeth Street Development - Fort Collins, Colorado EEC Project Number: 1162060 September 2016 EARTH ENGINEERING CONSULTANTS, LLC Approximate Boring Locations 1 Legend Site Photos (Photos taken in approximate location, in direction of arrow) WEST ELIZABETH DEVELOPMENT FORT COLLINS, COLORADO EEC PROJECT NO. 1162060 SEPTEMBER 2016 DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Existing Hot Mix Asphalt (HMA) - Approx. 5 Inches _ _ Existing Aggregate Base Course (ABC) - Approx. 4 Inches 1 Apparent Fill Material; Sandy Lean Clay w/ Gravel _ _ slightly cohesive subgrade, brown, moist, medium stiff 2 _ _ SANDY LEAN CLAY (CL) 3 brown _ _ very stiff 4 with calcareous deposits _ _ CS 5 8 6000 24.2 100.3 41 25 68.7 600 psf 0.1% _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 14 2000 14.2 _ _ 11 _ _ 12 _ _ SANDSTONE / SILTSTONE / CLAYSTONE 13 brown / grey / rust _ _ weathered, moderately hard to hard 14 _ _ % @ 1000 psf *bedrock classified as SANDY LEAN CLAY CS 15 50 9000+ 14.6 120.9 35 21 56.3 5000 psf 1.6% _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 50/7" 9000+ 14.1 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ CS 25 50/5" 9000+ 10.1 126.4 Continued on Sheet 2 of 2 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Continued from Sheet 1 of 2 26 _ _ SANDSTONE / SILTSTONE / CLAYSTONE 27 brown / grey / rust _ _ moderately hard to hard 28 _ _ 29 _ _ SS 30 50/6.5" 9000+ 13.9 _ _ 31 _ _ 32 _ _ 33 _ _ 34 _ _ 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL N/A DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Existing Hot Mix Asphalt (HMA) - Approx. 5 Inches _ _ Existing Aggregate Base Course (ABC) - Approx. 4 Inches 1 Apparent Fill Material; Sandy Lean Clay w/ Gravel _ _ slightly cohesive subgrade, brown, moist, medium stiff 2 _ _ SANDY LEAN CLAY (CL) CS 3 7 4000 19.0 108.9 dark brown _ _ stiff 4 with calcareous deposits _ _ SS 5 8 4500 24.0 _ _ 6 _ _ 7 _ _ 8 _ _ 9 *intermittent CLAYEY SAND with Gravel Lens _ _ CS 10 30 2000 18.0 116.4 28 14 39.3 <500 psf None _ _ 11 SANDSTONE / SILTSTONE / CLAYSTONE _ _ brown / grey / rust 12 weathered, moderately hard to hard _ _ 13 _ _ 14 _ _ SS 15 50 7000 16.5 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ % @ 1000 psf *bedrock classified as SANDY LEAN CLAY CS 20 50/6" 9000+ 13.2 124.2 32 16 54.6 3000 psf 1.1% _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ SS 25 50/7" 6000 14.6 BOTTOM OF BORING DEPTH 25.5' _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Existing Hot Mix Asphalt (HMA) - Approx. 5 Inches _ _ Existing Aggregate Base Course (ABC) - Approx. 4 Inches 1 Apparent Fill Material; Sandy Lean Clay w/ Gravel _ _ slightly cohesive subgrade, brown, moist, medium stiff 2 _ _ SANDY LEAN CLAY (CL) 3 dark brown _ _ stiff 4 with calcareous deposits _ _ CS 5 8 4000 20.7 103.6 800 psf 0.3% _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ *intermittent CLAYEY SAND with Gravel Lens SS 10 27 1000 26.1 _ _ 11 _ _ 12 _ _ SANDSTONE / SILTSTONE / CLAYSTONE 13 brown / grey / rust _ _ weathered, moderately hard to hard 14 _ _ CS 15 50 9000+ 15.8 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 50/6" 9000+ 12.7 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ SS 25 50/4" 900+ 9.5 130.1 BOTTOM OF BORING DEPTH 25.5' _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Existing Hot Mix Asphalt (HMA) - Approx. 5 Inches _ _ Existing Aggregate Base Course (ABC) - Approx. 4 Inches 1 Apparent Fill Material; Sandy Lean Clay w/ Gravel _ _ slightly cohesive subgrade, brown, moist, medium stiff 2 _ _ SANDY LEAN CLAY (CL) CS 3 10 4000 23.6 100.8 dark brown _ _ stiff 4 with traces of gravel _ _ SS 5 7 3000 17.1 _ _ 6 brown / red _ _ with sand & gravel seams 7 _ _ 8 _ _ 9 _ _ CS 10 10 2000 18.7 111.7 <500 psf None _ _ 11 _ _ 12 SANDSTONE / SILTSTONE / CLAYSTONE _ _ brown / grey / rust 13 weathered, moderately hard to hard _ _ 14 _ _ SS 15 50/7" 7000 14.5 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ CS 20 50/6" 9000+ 14.2 122.7 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ SS 25 50/7" 9000+ 17.6 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Existing Hot Mix Asphalt (HMA) - Approx. 5 Inches _ _ Existing Aggregate Base Course (ABC) - Approx. 4 Inches 1 Apparent Fill Material; Sandy Lean Clay w/ Gravel _ _ slightly cohesive subgrade, brown, moist, medium stiff 2 _ _ LEAN to FAT CLAY (CH / CL) 3 dark brown _ _ stiff 4 with calcareous deposits _ _ CS 5 9 4000 27.2 98.2 49 32 89.9 1100 psf 0.5% _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ *intermittent CLAYEY SAND with Gravel Lens SS 10 18 1000 12.3 _ _ 11 _ _ 12 _ _ SANDSTONE / SILTSTONE / CLAYSTONE 13 brown / grey / rust _ _ weathered, moderately hard to hard 14 _ _ CS 15 50/6.5" 9000+ 9.7 127.4 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 50/5" 8000 13.7 _ _ 21 _ _ 22 _ _ 23 _ _ 24 *bedrock classified as SANDY LEAN CLAY _ _ % @ 1000 psf CS 25 50/5" 9000+ 12.3 127.3 32 17 54.4 5200 psf 2.4% BOTTOM OF BORING DEPTH 25.0' _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 24.2% Dry Density: 105.5 pcf Ending Moisture: 23.8% Swell Pressure: 600 psf % Swell @ 500: 0.1% Sample Location: Boring 1, Sample 1, Depth 4' Liquid Limit: 41 Plasticity Index: 25 % Passing #200: 68.7% SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 14.6% Dry Density: 117.4 pcf Ending Moisture: 15.9% Swell Pressure: 5000 psf % Swell @ 1000: 1.6% Sample Location: Boring 1, Sample 3, Depth 14' Liquid Limit: 35 Plasticity Index: 21 % Passing #200: 56.3% SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Grey / Rust Sandstone / Siltstone / Claystone -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 18.0% Dry Density: 103.2 pcf Ending Moisture: 19.4% Swell Pressure: <500 psf % Swell @ 500: None Sample Location: Boring 2, Sample 3, Depth 9' Liquid Limit: 28 Plasticity Index: 14 % Passing #200: 39.3% SWELL / CONSOLIDATION TEST RESULTS Material Description: Clayey Sand with Gravel (SC) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 13.2% Dry Density: 125 pcf Ending Moisture: 14.6% Swell Pressure: 3000 psf % Swell @ 1000: 1.1% Sample Location: Boring 2, Sample 5, Depth 19' Liquid Limit: 32 Plasticity Index: 16 % Passing #200: 54.6% SWELL / CONSOLIDATION TEST RESULTS Material Description: Sandstone / Siltstone / Claystone Bedrock -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 20.7% Dry Density: 107.7 pcf Ending Moisture: 24.4% Swell Pressure: 800 psf % Swell @ 500: 0.3% Sample Location: Boring 3, Sample 1, Depth 4' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 18.7% Dry Density: 114.8 pcf Ending Moisture: 18.7% Swell Pressure: <500 psf % Swell @ 500: None Sample Location: Boring 4, Sample 3, Depth 9' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - SWELL / CONSOLIDATION TEST RESULTS Material Description: Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 27.2% Dry Density: 99.1 pcf Ending Moisture: 26.9% Swell Pressure: 1100 psf % Swell @ 500: 0.5% Sample Location: Boring 5, Sample 1, Depth 4' Liquid Limit: 49 Plasticity Index: 32 % Passing #200: 89.9% SWELL / CONSOLIDATION TEST RESULTS Material Description: Dark Brown Lean to Fat Clay (CH/CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 1415 - 1427 West Elizabeth St Fort Collins, Colorado 1162060 September 2016 Beginning Moisture: 12.3% Dry Density: 121.8 pcf Ending Moisture: 14.4% Swell Pressure: 5200 psf % Swell @ 1000: 2.4% Sample Location: Boring 5, Sample 5, Depth 24' Liquid Limit: 32 Plasticity Index: 17 % Passing #200: 54.4% SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Grey / Rust Sandstone / Siltstone / Claystone -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Exhibit 4 – Existing Drainage Plan LOT 2 FAIRVIEW SHOPPING CENTER LOT 2, POTT'S P.U.D. SS MH RIM=40.02 INV.IN (6" E)=32.32 INV IN (6" W)=32.17 INV IN (8" S)=32.12 INV.OUT (8" N)=32.07 SS MH RIM=39.78 INV IN (8" S)=32.48 INV IN (8" W)=32.58 INV OUT (8" N)=32.38 STM INLET RIM=41.17 INV (4" W)=39.34 BOTTOM=37.89 STM MH RIM=39.23 INV IN (12" W)=34.88 INV IN (15" S)=34.45 INV OUT (15" E)=34.38 STM GRATE GRATE=5939.05 INV (4" SE)=5938.36 FULL OF SILT STM GRATE GRATE=38.84 INV (10" S)=36.26 STM INLET RIM=41.12 INV (3" E)=39.54 BOTTOM=37.89 STM GRATE GRATE=36.89 INV OUT (NE 6")=34.4 STM MANHOLE RIM=40.82 INV IN (15" S)=37.47 INV OUT (15" E)=37.37 STM MH NO EVIDENCE FOUND ST MH RIM=40.01 INV IN (15" S)=35.01 INV IN (15" W)=36.16 INV IN (15" E)=35.11 INV OUT (15" N)=34.96 ST MH RIM=41.01 INV IN (12" W)=35.01 INV IN (15" S)=34.91 INV OUT (15" N)=34.86 STM AREA DRAIN GRATE=38.32 INV IN (6" E)=36.62 INV OUT (6" N)=36.59 STM MH Exhibit 5 – Proposed Drainage Plan ELIZABETH STREET PRIVATE DRIVE PARKING GARAGE MIXED USE BUILDING FFE: 40.50 PARKING GARAGE FFE: 40.50 AREA 1 AREA: 0.08 AC C-MINOR: 0.70 C-MAJOR: 0.88 PERVIOUS PAVERS AREA: 0.03 AC RUNON RATIO: 2.67 AREA 2 AREA: 0.31 AC C-MINOR: 0.64 C-MAJOR: 0.80 AREA 3 AREA: 0.03 AC C-MINOR: 0.42 C-MAJOR: 0.52 AREA 4 AREA: 0.68 AC C-MINOR: 0.91 C-MAJOR: 1.00 AREA 5 AREA: 0.22 AC C-MINOR: 0.71 C-MAJOR: 0.89 AREA 6 AREA: 0.54 AC C-MINOR: 0.83 C-MAJOR: 1.00 AREA 7 AREA: 0.05 AC C-MINOR: 0.79 C-MAJOR: 0.99 OFFSITE AREA: 0.02 AC C-MINOR: 0.15 C-MAJOR: 0.19 PERVIOUS PAVERS AREA: 0.12 AC RUNON RATIO: 2.58 PERVIOUS PAVERS AREA: 0.02 AC RUNON RATIO: 1.50 SAND FILTER AREA: 0.03 AC RUNON RATIO: 22.67 PERVIOUS PAVERS AREA: 0.09 AC RUNON RATIO: 2.44 BIOSWALE AREA: 0.06 AC RUNON RATIO: 9.00 DRAINAGE BASIN AREA (AC) IMPERVIOUS Exhibit 6 – Proposed Storm Sewer Calculations AREA (AC) LANDSCAPED AREA (AC) PERVIOUS PAVERS (AC) CMINOR (C2, C10) CMAJOR (C100 = Cf*CMINOR) TC (MIN) Q2 (CFS) Q10 (CFS) Q100 (CFS) LID TECHNIQUE LID AREA (AC) RUNON RATIO (AC/AC) AREA 1 0.08 0.04 0.01 0.03 0.70 0.88 5.00 0.16 0.27 0.70 PERVIOUS PAVERS 0.03 2.67 AREA 2 0.31 0.13 0.06 0.12 0.64 0.80 5.00 0.57 0.97 2.47 PERVIOUS PAVERS 0.12 2.58 AREA 3 0.03 0.00 0.01 0.02 0.42 0.52 5.00 0.04 0.06 0.16 PERVIOUS PAVERS 0.02 1.50 AREA 4 0.68 0.65 0.03 0.00 0.91 1.00 5.00 1.77 3.03 6.77 SAND FILTER 0.03 22.67 AREA 5 0.22 0.11 0.02 0.09 0.71 0.89 5.00 0.45 0.76 1.95 PERVIOUS PAVERS 0.09 2.44 AREA 6 0.54 0.46 0.08 0.00 0.83 1.00 5.00 1.28 2.19 5.37 BIOSWALE 0.06 9.00 AREA 7 0.05 0.04 0.01 0.00 0.79 0.99 5.00 0.11 0.19 0.49 N/A N/A N/A OFFSITE 0.02 0.00 0.02 0.00 0.15 0.19 5.00 0.01 0.01 0.04 N/A N/A N/A TOTAL 1.93 1.43 0.24 0.26 0.80 1.00 N.A 4.38 7.49 17.94 N/A N/A N/A 10 OF 16 THE HUB ON CAMPUS FORT COLLINS FORT COLLINS, CO 80521 PROPOSED DRAINAGE PLAN NORTH DRAINAGE LEGEND Know what's below. Call before you dig. ON-SITE TREATMENT BY LID REQUIREMENT POROUS PAVEMENT REQUIREMENT LID TABLE HUB ON CAMPUS FT. COLLINS RIM=40.85 INV IN (12" S)=36.10 INV IN (12" W)=35.85 INV OUT (12" E)=35.80 EX1 AREA: 0.63 AC C-MINOR: 0.81 C-MAJOR: 1.00 EX4 AREA: 0.05 AC C-MINOR: 0.79 C-MAJOR:0.99 ELIZABETH STREET PRIVATE DRIVE EX2 AREA: 0.13 AC C-MINOR: 0.95 C-MAJOR: 1.00 EX3 AREA: 0.25 AC C-MINOR: 0.89 C-MAJOR: 1.00 EX5 AREA: 0.14 AC C-MINOR: 0.95 C-MAJOR: 1.00 OFFSITE 1 AREA: 0.02 AC C-MINOR: 0.15 C-MAJOR:0.19 OFFSITE 2 AREA: 0.01 AC C-MINOR: 0.95 C-MAJOR:1.00 OFFSITE 3 AREA: 0.02 AC C-MINOR: 0.55 C-MAJOR:0.69 OFFSITE 4 AREA: 0.33 AC C-MINOR: 0.83 C-MAJOR: 1.00 OFFSITE 5 AREA: 0.35 AC C-MINOR: 0.90 C-MAJOR: 1.00 DRAINAGE BASIN AREA (AC) IMPERVIOUS AREA (AC) PERVIOUS AREA (AC) CMINOR (C2, C10) CMAJOR (C100 = Cf*CMINOR) TC (MIN) Q2 (CFS) Q10 (CFS) Q100 (CFS) OUTLET POINT EX1 0.63 0.52 0.11 0.81 1.00 5.00 1.45 2.49 6.27 EXISTING STORM GRATE EX2 0.13 0.13 0.00 0.95 1.00 5.00 0.35 0.60 1.29 BUILDING ROOF EX3 0.25 0.23 0.02 0.89 1.00 5.00 0.63 1.08 2.49 EXISTING STORM GRATE EX4 0.05 0.04 0.01 0.79 0.99 5.00 0.11 0.19 0.49 EXISTING STORM GRATE EX5 0.14 0.14 0.00 0.95 1.00 5.00 0.38 0.65 1.39 BUILDING ROOF OFFSITE 1 0.02 0.00 0.02 0.15 0.19 5.00 0.01 0.01 0.04 OFFSITE - SOUTH OFFSITE 2 0.01 0.01 0.00 0.95 1.00 5.00 0.03 0.05 0.10 OFFSITE - WEST OFFSITE 3 0.02 0.01 0.01 0.55 0.69 5.00 0.03 0.05 0.14 OFFSITE - WEST OFFSITE 4 0.33 0.28 0.05 0.83 1.00 5.00 0.78 1.33 3.28 OFFSITE - NORTH OFFSITE 5 0.35 0.33 0.02 0.90 1.00 5.00 0.90 1.54 3.48 OFFSITE STORM GRATE - EAST TOTAL 1.93 1.69 0.24 0.85 1.00 N/A 4.68 7.99 18.97 THE HUB ON CAMPUS FORT COLLINS FORT COLLINS, CO 80521 DRAINAGE LEGEND THE HUB ON CAMPUS FORT COLLINS 9 OF 16 EXISTING DRAINAGE PLAN NORTH Know what's below. Call before you dig. SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 9/7/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 6.5' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-5 SEPTEMBER 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 9/7/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 9.5' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-4 SEPTEMBER 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 9/7/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 7' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-3 SEPTEMBER 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 9/7/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 8.5' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-2 SEPTEMBER 2016 9/7/2016 AFTER DRILLING N/A SURFACE ELEV 24 HOUR N/A FINISH DATE SHEET 2 OF 2 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 11' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-1 SEPTEMBER 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 9/7/2016 AFTER DRILLING N/A SHEET 1 OF 2 WATER DEPTH START DATE 9/7/2016 WHILE DRILLING 11' 1415 - 1427 WEST ELIZABETH ST FORT COLLINS, COLORADO PROJECT NO: 1162060 LOG OF BORING B-1 SEPTEMBER 2016 Soil Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Sands 50% or more coarse fraction passes No. 4 sieve Fine-Grained Soils 50% or more passes the No. 200 sieve <0.75 OL Gravels with Fines more than 12% fines Clean Sands Less than 5% fines Sands with Fines more than 12% fines Clean Gravels Less than 5% fines Gravels more than 50% of coarse fraction retained on No. 4 sieve Coarse - Grained Soils more than 50% retained on No. 200 sieve CGravels with 5 to 12% fines required dual symbols: Kif soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel", whichever is predominant. <0.75 OH Primarily organic matter, dark in color, and organic odor ABased on the material passing the 3-in. (75-mm) sieve ECu=D60/D10 Cc= HIf fines are organic, add "with organic fines" to group name LIf soil contains ≥ 30% plus No. 200 predominantly sand, add "sandy" to group name. MIf soil contains ≥30% plus No. 200 predominantly gravel, add "gravelly" to group name. DSands with 5 to 12% fines require dual symbols: BIf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. FIf soil contains ≥15% sand, add "with sand" to GIf fines classify as CL-ML, use dual symbol GC- CM, or SC-SM. Silts and Clays Liquid Limit less than 50 Silts and Clays Liquid Limit 50 or more 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 80 90 100 110 PLASTICITY INDEX (PI) LIQUID LIMIT (LL) ML OR OL MH OR OH For Classification of fine-grained soils and fine-grained fraction of coarse-grained soils. Equation of "A"-line Horizontal at PI=4 to LL=25.5 then PI-0.73 (LL-20) Equation of "U"-line Vertical at LL=16 to PI-7, then PI=0.9 (LL-8) CL-ML HARDNESS AND DEGREE OF CEMENTATION: Limestone and Dolomite: Hard Difficult to scratch with knife. Moderately Can be scratched easily with knife. Hard Cannot be scratched with fingernail. Soft Can be scratched with fingernail. Shale, Siltstone and Claystone: Hard Can be scratched easily with knife, cannot be scratched with fingernail. Moderately Can be scratched with fingernail. Hard Soft Can be easily dented but not molded with fingers. Sandstone and Conglomerate: Well Capable of scratching a knife blade. Cemented Cemented Can be scratched with knife. Poorly Can be broken apart easily with fingers. Cemented Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/14/2016 Page 2 of 4