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HomeMy WebLinkAboutCAPSTONE COTTAGES - PDP - PDP140004 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGeotechnical Engineering Report Capstone Cottages of Fort Collins Northeast of N. Lemay Avenue and E. Lincoln Avenue Fort Collins, Colorado March 28, 2014 Terracon Project No. 20145005 Prepared for: Capstone Collegiate Communities, LLC Birmingham, Alabama Prepared by: Terracon Consultants, Inc. Fort Collins, Colorado TABLE OF CONTENTS Page EXECUTIVE SUMMARY .............................................................................................................i 1.0 INTRODUCTION ............................................................................................................. 1 2.0 PROJECT INFORMATION ............................................................................................. 2 2.1 Project Description ...............................................................................................2 2.2 Site Location and Description...............................................................................2 3.0 SUBSURFACE CONDITIONS ........................................................................................ 3 3.1 Typical Subsurface Profile ...................................................................................3 3.2 Laboratory Testing ...............................................................................................3 3.3 Groundwater ........................................................................................................3 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ...................................... 5 4.1 Geotechnical Considerations ...............................................................................5 4.1.1 Existing, Undocumented Fill .....................................................................5 4.1.2 Shallow Groundwater ...............................................................................5 4.1.3 Weak Soils near Foundation Elevations ...................................................5 4.1.4 Expansive Soils and Bedrock ...................................................................5 4.2 Earthwork.............................................................................................................6 4.2.1 Site Preparation ........................................................................................6 4.2.2 Excavation ................................................................................................6 4.2.3 Subgrade Preparation ...............................................................................7 4.2.4 Fill Materials and Placement ......................................................................8 4.2.5 Compaction Requirements ........................................................................9 4.2.6 Utility Trench Backfill ................................................................................9 4.2.7 Grading and Drainage .............................................................................10 4.2.8 Exterior Slab Design and Construction ...................................................11 4.2.9 Corrosion Protection ...............................................................................11 4.3 Foundations .......................................................................................................11 4.3.1 Frost Protected Post-tensioned Slabs .....................................................12 4.3.2 Post-Tensioned Slabs – Design Recommendations ...............................12 4.3.3 Post-Tensioned Slabs – Construction Considerations ...............................13 4.3.4 Spread Footings - Design Recommendations .........................................14 4.3.5 Spread Footings - Construction Considerations ......................................15 4.4 Seismic Considerations......................................................................................16 4.5 Floor Systems ....................................................................................................16 4.6 Lateral Earth Pressures .....................................................................................16 4.8 Pavements .........................................................................................................18 4.8.1 Pavements – Subgrade Preparation .......................................................18 4.8.2 Pavements – Design Recommendations ................................................18 4.8.3 Pavements – Construction Considerations .............................................21 4.8.4 Pavements – Maintenance .....................................................................21 5.0 GENERAL COMMENTS ............................................................................................... 21 TABLE OF CONTENTS (continued) Appendix A – FIELD EXPLORATION Exhibit A-1 Site Location Map Exhibit A-2 Exploration Plan Exhibit A-3 Field Exploration Description Exhibits A-4 to A-19 Boring Logs Appendix B – LABORATORY TESTING Exhibit B-1 Laboratory Testing Description Exhibit B-2 Atterberg Limits Test Results Exhibits B-3 and B-4 Grain-size Distribution Test Results Exhibits B-5 to B-9 Swell-consolidation Test Results Exhibit B-10 Corrosivity Test Results Appendix C – SUPPORTING DOCUMENTS Exhibit C-1 General Notes Exhibit C-2 Unified Soil Classification System Exhibit C-3 Description of Rock Properties Exhibit C-4 Laboratory Test Significance and Purpose Exhibits C-5 and C-6 Report Terminology Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable i EXECUTIVE SUMMARY A geotechnical investigation has been performed for the proposed Capstone Cottages of Fort Collins to be constructed northeast of North Lemay Avenue and East Lincoln Avenue in Fort Collins, Colorado. Previously, Terracon prepared a Geotechnical Engineering Report (Project No. 20045173; report dated November 17, 2004) for this site that included completion of five (5) borings throughout the site. Boring logs for the previously completed borings are presented as Exhibits A-4 through A-8 in Appendix A. Eleven (11) borings, presented as Exhibits A-9 through A-19 and designated as Boring No. 6 through Boring No. 16, were performed to depths of approximately 17 to 23 feet below existing site grades. This report specifically addresses the recommendations for the proposed apartment buildings, cottage buildings, and associated pavements. Borings performed in these areas are for informational purposes and will be utilized by others. Based on the information obtained from our previous and current subsurface explorations, the site can be developed for the proposed project. However, the following geotechnical considerations were identified and will need to be considered: „ The proposed buildings may be supported on shallow, post-tensioned slab foundation systems bearing on scarified, moisture conditioned, recompacted native soils or on newly placed engineered fill. Spread footings constructed on stable subgrade or new, properly placed engineered fill is also considered an appropriate foundation system for support of the proposed buildings. „ Unstable and/or nearly saturated to wet soils should be anticipated as excavations approach the level of groundwater. Foundations extending below grade near the level of groundwater will require stabilization of the subgrade and/or construction dewatering prior to construction. „ If the Owner selects a post-tensioned slab foundation system, the foundation will also function as the floor system for the proposed buildings. If a conventional spread footing foundation system is selected, we recommend a slab-on-grade floor system for the proposed buildings. „ The amount of movement of foundations, slabs, pavements, etc. will be related to the wetting of underlying supporting soils. Therefore, it is imperative the recommendations discussed in the 4.2.7 Grading and Drainage section of this report be followed to reduce potential movement. „ Groundwater was encountered at depths ranging from about 1½ to 7 feet below the existing ground surface during our field study. Shallow groundwater conditions will prohibit basement construction, significantly impact installation of deep utilities buried below the site as well as areas planned for cuts on the order of 2 feet or more. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable ii „ Budget contingencies should be provided in the contract documents for stabilizing soft subgrade soils expected below portions of the project site. „ The 2012 International Building Code, Table 1613.5.2 IBC seismic site classification for this site is D. „ Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support. We therefore recommend that Terracon be retained to monitor this portion of the work. This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. Responsive Ŷ Resourceful Ŷ Reliable 1 GEOTECHNICAL ENGINEERING REPORT Capstone Cottages of Fort Collins Northeast of N. Lemay Avenue and E. Lincoln Avenue Fort Collins, Colorado Terracon Project No. 20145005 March 28, 2014 1.0 INTRODUCTION This report presents the results of our geotechnical engineering services performed for the proposed Capstone Cottages of Fort Collins to be located at Northeast of N. Lemay Avenue and E. Lincoln Avenue in Fort Collins, Colorado. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: „ subsurface soil and bedrock conditions „ foundation design and construction „ groundwater conditions „ floor slab design and construction „ grading and drainage „ pavement construction „ lateral earth pressures „ earthwork „ seismic considerations Our geotechnical engineering scope of work for this project included review and compilation of previously completed geotechnical data at the site, the initial site visit, the advancement of eleven (11) supplemental test borings to depths ranging from approximately 17 to 23 feet below existing site grades, laboratory testing for soil engineering properties and engineering analyses to provide foundation, floor system, and pavement design and construction recommendations. Logs of the borings along with an Exploration Plan (Exhibit A-2) are included in Appendix A. The results of the laboratory testing performed on soil and bedrock samples obtained from the site during the field exploration are included in Appendix B. Previously, Terracon performed a geotechnical study at the project site, as presented in Report No. 20045173 dated November 17, 2004. Information from the previous study was used in the evaluation of the current project. Boring logs and laboratory test results from the previous study are included in this report. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 2 2.0 PROJECT INFORMATION 2.1 Project Description Item Description Site layout Refer to the Exploration Plan (Exhibit A-2 in Appendix A) Structures The project is a mix of two product types including three-story “lodge” or apartment buildings and two-story “cottages” with varying sizes. We anticipate the multi-family buildings will be wood-framed structures constructed on cast-in-place concrete foundations with no basements. Grading At the time this report was prepared, site grading plans were not fully developed. We anticipate cuts and fills on the order of 10 feet or less will be necessary for the proposed construction. Deeper cuts may be necessary for the installation of buried utilities. Traffic loading We understand both city-maintained roadways and privately- maintained roadways are planned for this site. Expected traffic loading was not provided; however, we anticipate that traffic loads will be produced primarily by automobile traffic, occasional delivery and trash removal trucks, and occasional bus traffic. Based on the information provided to us on a Conceptual Site Plan, the proposed Duff Drive will be a collector road and the proposed International Boulevard will be a 2-lane arterial road. We have assumed Duff Drive will be classified as an industrial/commercial collector according to the Larimer County Urban Area Street Standards (LCUASS). LCUASS indicates a design Equivalent Single Axel Load (ESAL) of 730,000 should be used for an industrial/commercial collector and two-lane arterial roadways. 2.2 Site Location and Description Item Description Location The project site is located northeast of North Lemay Avenue and East Lincoln Avenue in Fort Collins, Colorado. Existing site features The site is currently undeveloped land with Bank of Colorado located to the southwest, Buffalo Run Student Housing to the south, and irrigated farmland to the north. The site is bordered to the east by industrial and commercial properties. Current ground cover The site is covered with native grasses and weeds. Existing topography The site is relatively flat gently sloping from the northwest to the southeast. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 3 3.0 SUBSURFACE CONDITIONS 3.1 Typical Subsurface Profile Specific conditions encountered at each boring location are indicated on the individual boring logs included in Appendix A. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Based on the results of the previously completed and supplemental borings, subsurface conditions on the project site can be generalized as follows: Material Description Approximate Depth to Bottom of Stratum (feet) Consistency/Density/Hardness Lean clay with varying amounts of sand About 1 to 7 feet below existing site grades. Soft to very stiff Sand with varying amounts of silt and gravel About 14½ to 22 feet below existing site grades. Loose to very dense Siltstone/claystone bedrock To the maximum depth of exploration of about 24½ feet. Weathered to very hard The upper ½ to 1 foot of the siltstone and/or siltstone/claystone bedrock was weathered. 3.2 Laboratory Testing Representative soil samples were selected for swell-consolidation testing and exhibited slight compression to 0.1 percent swell when wetted. The siltstone bedrock is also considered to have low expansive potential or be non-expansive. Samples of site soils and bedrock selected for plasticity testing exhibited medium to high plasticity with liquid limits ranging from non-plastic to 49 and plasticity indices ranging from 5 to 29. Laboratory test results are presented in Appendix B. 3.3 Groundwater The boreholes were observed while drilling and after completion for the presence and level of groundwater. In addition, delayed water levels were also obtained in some borings. The water levels observed in the boreholes are noted on the attached boring logs, and are summarized below: Boring Number Depth to groundwater while drilling, ft. Depth to groundwater several days after drilling, ft. Elevation of groundwater several days after drilling, ft. 1 3 Backfilled -- 2 3 Backfilled -- Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 4 Boring Number Depth to groundwater while drilling, ft. Depth to groundwater several days after drilling, ft. Elevation of groundwater several days after drilling, ft. 3 3 Backfilled -- 4 3 Backfilled -- 5 6 Backfilled -- 6 6 Backfilled -- 7 6 Backfilled -- 8 6 Backfilled -- 9 7 2.5 93.3 10 2 1.5 94.3 11 6 Backfilled -- 12 3 Backfilled -- 13 3 2.2 91.8 14 4 Backfilled -- 15 4 Backfilled -- 16 5 Backfilled -- These observations represent groundwater conditions at the time of the field exploration, and may not be indicative of other times or at other locations. Groundwater levels can be expected to fluctuate with varying seasonal and weather conditions, and other factors. Groundwater level fluctuations occur due to seasonal variations in amount of rainfall, runoff and other factors not evident at the time the borings were performed. Therefore, groundwater levels during construction or at other times in the life of the structures may be higher or lower than the levels indicated on the boring logs. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater piezometers, and periodic measurement of groundwater levels over a sufficient period of time. Terracon has provided a proposal to install five (5) temporary piezometers at the site to facilitate groundwater monitoring. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 5 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION 4.1 Geotechnical Considerations Based on subsurface conditions encountered in the borings, the site appears suitable for the proposed construction from a geotechnical point of view provided certain precautions and design and construction recommendations described in this report are followed. We have identified geotechnical conditions that could impact design and construction of the proposed structures, pavements, and other site improvements. 4.1.1 Existing, Undocumented Fill Existing fill materials were not encountered in any of our borings on this site. However, mounds of soil and/or deleterious materials were observed during our field investigation. We do not possess any information regarding the source of the soil and/or deleterious materials. We are uncertain what is contained within the stockpiles; our scope of services did not include exploration of these materials. We recommend the existing mounds of fill and deleterious materials be thoroughly inspected prior to consideration for use as on-site fill materials. Support of foundations, floor slabs, and pavements on or above existing fill soils is discussed in this report. However, even with the recommended construction testing services, there is an inherent risk for the owner that compressible fill or unsuitable material within or buried by the fill will not be discovered. This risk of unforeseen conditions cannot be eliminated without completely removing the existing fill, but can be reduced by performing additional testing and evaluation. 4.1.2 Shallow Groundwater As previously stated, groundwater was measured at depths ranging from about 1½ to 7 feet below existing site grades. Terracon recommends maintaining a separation of at least 3 feet between the bottom of proposed foundations and/or pavement subgrade and measured groundwater levels. It is also possible and likely that groundwater levels below this site may rise. 4.1.3 Weak Soils near Foundation Elevations Unstable and/or nearly saturated soils should be anticipated as excavations approach the level of groundwater. Foundations extending below grade to the groundwater depth will require stabilization of the subgrade and/or construction dewatering prior to construction. Recommendations for stabilization of foundation subgrade are presented in subsequent sections of this report. 4.1.4 Expansive Soils and Bedrock Laboratory testing indicates the native clay soils and siltstone bedrock exhibited slight compression to 0.1 percent swell at the samples in-situ moisture content. However, it is our Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 6 opinion these materials will exhibit a higher expansive potential if the clays undergo a significant loss of moisture. This report provides recommendations to help mitigate the effects of soil shrinkage and expansion. However, even if these procedures are followed, some movement and cracking in the structures, pavements, and flatwork should be anticipated. The severity of cracking and other damage such as uneven floor slabs will probably increase if any modification of the site results in excessive wetting or drying of the expansive clays. Eliminating the risk of movement and distress is generally not feasible, but it may be possible to further reduce the risk of movement if significantly more expensive measures are used during construction. It is imperative the recommendations described in section 4.2.7 Grading and Drainage of this report be followed to reduce movement. 4.2 Earthwork The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project. All earthwork on the project should be observed and evaluated by Terracon on a full-time basis. The evaluation of earthwork should include observation of over-excavation operations, testing of engineered fills, subgrade preparation, subgrade stabilization, and other geotechnical conditions exposed during the construction of the project. 4.2.1 Site Preparation Prior to placing any fill, strip and remove existing vegetation and any other deleterious materials from the proposed construction areas. Stripped organic materials should be wasted from the site or used to re-vegetate landscaped areas or exposed slopes (if any) after completion of grading operations. Prior to the placement of fills, the site should be graded to create a relatively level surface to receive fill, and to provide for a relatively uniform thickness of fill beneath proposed structures. If fill is placed in areas of the site where existing slopes are steeper than 5:1 (horizontal:vertical), the area should be benched to reduce the potential for slippage between existing slopes and fills. Benches should be wide enough to accommodate compaction and earth moving equipment, and to allow placement of horizontal lifts of fill. 4.2.2 Excavation It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. Excavations into the on-site soils may encounter weak and/or saturated soil conditions with possible caving conditions. Excavation penetrating the bedrock may require the use of specialized heavy-duty equipment, together with ripping or jack-hammering to advance the excavation and facilitate rock break-up Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 7 and removal. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project if excavations will extend into bedrock. The soils to be excavated can vary significantly across the site as their classifications are based solely on the materials encountered in widely-spaced exploratory test borings. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions are encountered at the time of construction, the actual conditions should be evaluated to determine any excavation modifications necessary to maintain safe conditions. Although evidence of underground facilities such as septic tanks, vaults, basements, and utilities was not observed during the site reconnaissance, such features could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. Depending upon depth of excavation and seasonal conditions, surface water infiltration and/or groundwater may be encountered in excavations on the site. It is anticipated that pumping from sumps may be utilized to control water within excavations. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth. The subgrade soil conditions should be evaluated during the excavation process and the stability of the soils determined at that time by the contractors’ Competent Person. Slope inclinations flatter than the OSHA maximum values may have to be used. 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. If any excavation, including a utility trench, is extended to a depth of more than 20 feet, it will be necessary to have the side slopes and/or shoring system designed by a professional engineer. As a safety measure, it is recommended that all vehicles and soil piles be kept a minimum lateral distance from the crest of the slope equal to the slope height. The exposed slope face should be protected against the elements 4.2.3 Subgrade Preparation After the deleterious materials have been removed from the construction areas, the top 10 inches of the exposed ground surface should be scarified, moisture conditioned, and recompacted to at least 95 percent of the maximum dry unit weight as determined by ASTM D698 before any new fill, foundation, or pavement is placed. In addition, large cobbles may be encountered beneath foundation areas. Such conditions could create point loads on the bottom of foundations, increasing the potential for differential foundation movement. If such conditions are encountered in the foundation excavations, the Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 8 cobbles should be removed and be replaced with engineered fill, conditioned to near optimum moisture content and compacted. After the bottom of the excavation has been compacted, engineered fill can be placed to bring the building pads and pavement subgrade to the desired grade. Engineered fill should be placed in accordance with the recommendations presented in subsequent sections of this report. The stability of the subgrade may be affected by precipitation, repetitive construction traffic or other factors. If unstable conditions develop, workability may be improved by scarifying and drying. Alternatively, over-excavation of wet zones and replacement with granular materials may be used, or crushed gravel and/or rock can be tracked or “crowded” into the unstable surface soil until a stable working surface is attained. Lightweight excavation equipment may also be used to reduce subgrade pumping. Budget contingencies should be provided in the contract documents for stabilizing soft subgrade soils expected below portions of the project site. 4.2.4 Fill Materials and Placement The on-site soils or approved granular and low plasticity cohesive imported materials may be used as fill material. The soil removed from this site that is free of organic or objectionable materials, as defined by a field technician who is qualified in soil material identification and compaction procedures, can be re-used as fill for the building pads and pavement subgrade. It should be noted that on-site soils may require reworking to adjust the moisture content to meet the compaction criteria. Imported soils (if required) should meet the following material property requirements: Gradation Percent finer by weight (ASTM C136) 4” 100 3” 70-100 No. 4 Sieve 50-100 No. 200 Sieve 10-50 Soil Properties Value Liquid Limit 30 (max.) Plastic Limit 15 (max.) Maximum Expansive Potential (%) Non-expansive1 1. Measured on a sample compacted to approximately 95 percent of the maximum dry unit weight as determined by ASTM D698 at optimum moisture content. The sample is confined under a 100 psf surcharge and submerged. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 9 4.2.5 Compaction Requirements Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. Item Description Fill lift thickness 9 inches or less in loose thickness when heavy, self- propelled compaction equipment is used 4 to 6 inches in loose thickness when hand-guided equipment (i.e. jumping jack or plate compactor) is used Minimum compaction requirements 95 percent of the maximum dry unit weight as determined by ASTM D698 Moisture content cohesive soil (clay) -1 to +3 % of the optimum moisture content Moisture content cohesionless soil (sand) -3 to +2 % of the optimum moisture content 1. We recommend engineered fill be tested for moisture content and compaction during placement. Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved. 2. Specifically, moisture levels should be maintained low enough to allow for satisfactory compaction to be achieved without the fill material pumping when proofrolled. 3. Moisture conditioned clay materials should not be allowed to dry out. A loss of moisture within these materials could result in an increase in the material’s expansive potential. Subsequent wetting of these materials could result in undesirable movement. 4.2.6 Utility Trench Backfill All trench excavations should be made with sufficient working space to permit construction including backfill placement and compaction. All underground piping within or near the proposed structures should be designed with flexible couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts in foundation walls should be oversized to accommodate differential movements. It is imperative that utility trenches be properly backfilled with relatively clean materials. If utility trenches are backfilled with relatively clean granular material, they should be capped with at least 18 inches of cohesive fill in non-pavement areas to reduce the infiltration and conveyance of surface water through the trench backfill. Utility trenches are a common source of water infiltration and migration. All utility trenches that penetrate beneath the buildings should be effectively sealed to restrict water intrusion and flow through the trenches that could migrate below the buildings. We recommend constructing an effective clay “trench plug” that extends at least 5 feet out from the face of the building exteriors. The plug material should consist of clay compacted at a water content at or above the soil’s Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 10 optimum water content. The clay fill should be placed to completely surround the utility line and be compacted in accordance with recommendations in this report. It is strongly recommended that a representative of Terracon provide full-time observation and compaction testing of trench backfill within building and pavement areas. 4.2.7 Grading and Drainage All grades must be adjusted to provide effective drainage away from the proposed buildings and pavements during construction and maintained throughout the life of the proposed project. Infiltration of water into foundation excavations must be prevented during construction. Landscape irrigation adjacent to foundations should be minimized or eliminated. Water permitted to pond near or adjacent to the perimeter of the structures (either during or post- construction) can result in significantly higher soil movements than those discussed in this report. As a result, any estimations of potential movement described in this report cannot be relied upon if positive drainage is not obtained and maintained, and water is allowed to infiltrate the fill and/or subgrade. Exposed ground (if any) should be sloped at a minimum of 10 percent grade for at least 10 feet beyond the perimeter of the proposed buildings, where possible. The use of swales, chases and/or area drains may be required to facilitate drainage in unpaved areas around the perimeter of the buildings. Backfill against foundations and exterior walls should be properly compacted and free of all construction debris to reduce the possibility of moisture infiltration. After construction of the proposed buildings and prior to project completion, we recommend verification of final grading be performed to document positive drainage, as described above, has been achieved. Flatwork and pavements will be subject to post-construction movement. Maximum grades practical should be used for paving and flatwork to prevent areas where water can pond. In addition, allowances in final grades should take into consideration post-construction movement of flatwork, particularly if such movement would be critical. Where paving or flatwork abuts the structures, care should be taken that joints are properly sealed and maintained to prevent the infiltration of surface water. Planters located adjacent to structures should preferably be self-contained. Sprinkler mains and spray heads should be located a minimum of 5 feet away from the building line(s). Low-volume, drip style landscaped irrigation should not be used near the building. Roof drains should discharge on to pavements or be extended away from the structures a minimum of 10 feet through the use of splash blocks or downspout extensions. A preferred alternative is to have the roof drains discharge by solid pipe to storm sewers or to a detention pond or other appropriate outfall. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 11 4.2.8 Exterior Slab Design and Construction Exterior slabs on-grade, exterior architectural features, and utilities founded on, or in backfill or the site soils will likely experience some movement due to the volume change of the material. Potential movement could be reduced by: „ Minimizing moisture increases in the backfill; „ Controlling moisture-density during placement of the backfill; „ Using designs which allow vertical movement between the exterior features and adjoining structural elements; and „ Placing control joints on relatively close centers. 4.2.9 Corrosion Protection Results of water-soluble sulfate testing indicate that ASTM Type V portland cement or approved substitute should be specified for all project concrete on and below grade. Foundation concrete should be designed for very severe sulfate exposure in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. 4.3 Foundations Terracon considered several foundation alternatives for support of the proposed structures including: „ Traditional post-tensioned slabs „ Frost protected post-tensioned slabs „ Spread footings „ Drilled piers or helical piles There are advantages and disadvantages associated with each of the foundation alternatives we believe are suitable for this project site. Shallow groundwater conditions encountered below this site will likely impact spread footing and traditional post-tensioned slab foundations. Foundation excavations approaching the level of groundwater will likely encounter soft to very loose and nearly saturated to wet soil conditions. Stabilization of foundation subgrade soils will be required prior to spread footing or traditional post-tensioned slab foundation construction. Drilled pier foundations bottomed in bedrock will require temporary casing, concrete placement using tremie methods and rock coring bits to achieve penetration in the very hard bedrock below the site. Helical pile foundations may be comparatively costly and achieving torque in the sand and gravel below the site may be difficult. We believe constructing the proposed buildings on frost protected post-tensioned slabs is a suitable foundation alternative that will reduce impacts of shallow groundwater and limit areas where subgrade stabilization will be required. The bearing depth for frost protected post- tensioned slabs will be significantly less than the bearing depth for other conventional shallow foundations systems such as spread footings and traditional post-tensioned slab foundations. However, there will be requirements to protect the foundation bearing soils from frost action that will include placement of insulation adjacent to the perimeter edges of foundations. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 12 Design recommendations for the recommended foundation alternatives for the proposed structures and related structural elements are presented in the following sections. 4.3.1 Frost Protected Post-tensioned Slabs A frost protected shallow foundation is a foundation that does not extend below the design frost depth, but is protected against effects of frost. Protection from frost heave is achieved by insulating to retard frost penetration below the foundation and to retard heat flow from beneath the foundation. Installation of insulation will allow shallower foundation bearing depths to be possible with significantly reduced risk of frost damage. Recommendations for design and construction of frost protected shallow foundations are presented in Design and Construction of Frost-Protected Shallow Foundations prepared by the American Society of Civil Engineers (ASCE 32-01). 4.3.2 Post-Tensioned Slabs – Design Recommendations Based on the subsurface conditions encountered, use of post-tensioned slabs is feasible for support of the structures provided some foundation movement can be tolerated and: „ The post-tensioned slab foundations are properly designed and constructed. „ Approved materials supporting the foundation are properly placed and compacted. „ Proper surface drainage is maintained throughout the life of the structures. „ Prudent landscaping measures are used. In our opinion, total foundation movements on the order of about 1 inch should be expected. Provided foundations are properly designed, foundation movements could result in periodic, and possibly seasonal, cosmetic distress to drywall, window frames, door frames and other features. We would anticipate that the frequency of distress and amount of movement would generally diminish with time provided proper drainage is established and/or maintained. We believe potential total foundation movements can be reduced to ½ to ¾ inch or less if at least 3 feet of imported granular engineered fill is placed directly below the post-tensioned slab foundations. The granular fill should consist of materials within the specified limits presented in the 4.2.4 Fill Materials and Placement section of this report. Based on the subsurface conditions, post-tensioned slabs should be designed using criteria outlined by the Post-Tensioning Institute1 based on the following: 1 (2004, Third Edition), Design (and Construction) of Post-Tensioned Slabs-on-Ground, Post- Tensioning Institute. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 13 Post-tensioned Slab Design Parameter PTI, Third Edition 2012 IBC/IRC Edge Moisture Variation Distance, em (feet) Center Lift Condition 7½ Edge Lift Condition 4 Differential Soil Movement, ym (inches) Center Lift Condition ¼ Edge Lift Condition ¾ „ Maximum Allowable Net Bearing Pressure ............................................................... 2,000 psf „ Slab-Subgrade Friction Coefficient, P x on polyethylene sheeting ................................................................................ 0.75 x on cohesionless soils ...................................................................................... 1.00 x on cohesive soils............................................................................................. 2.00 The maximum allowable net bearing pressure may be increased by 1/3 for transient wind or seismic loading. It should be noted that ym is the estimated vertical movement at the edges of a uniformly loaded slab. These are theoretical values that are used in the design of post-tensioned slabs-on-grade and do not represent the movements that would be expected from the actual loading conditions. As previously discussed, the use of post-tensioned slabs assumes that some potential movement is considered acceptable. 4.3.3 Post-Tensioned Slabs – Construction Considerations Post-tensioned slabs, thickened or turndown edges and/or interior beams should be designed and constructed in accordance with the requirements of the PTI and the American Concrete Institute (ACI). As previously discussed, foundations should be protected from frost heave using insulation. If traditional post-tensioned slab foundations are selected, exterior slab edges should be placed a minimum of 30 inches below finished grade for frost protection. Finished grade is the lowest adjacent grade for perimeter beams. Extending exterior slab edges to depths of at least 30 inches will likely encroach upon soft to very loose and nearly saturated to wet soils requiring stabilization of subgrade prior to construction. If portions of the building floor slab will be unheated, such as patios and entryways, consideration should be given to structurally separating these areas of the slab from the remaining interior portion of the slab. Exterior slab areas may be cantilevered portions of the slab which are subject to uplift from frost heave and swelling of the expansive soils, sometimes beyond those used for design, due to over watering of adjacent to landscaped areas. Such movement in the exterior slabs can result in change in slab grade to the point where negative grade results and water ponds adjacent to the interior areas of the slab. Repairs of such conditions are difficult and costly, particularly if the floor slabs are post-tensioned slabs. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 14 Exterior slabs in unheated areas are subject to frost heave beneath the slab. Therefore, in design of the exterior slabs, potential movement from frost heave should be considered in the design. It should be noted that the presences of 1 to 2-foot steps within long spans of post-tensioned slabs could create a situation where the slabs at different elevations perform independently of one another unless the steps are properly reinforced and designed to tie the slabs together to act as one rigid structure. We strongly recommend that joints be designed within the full height of the structure of the building over each step in order to help the structure be capable of withstanding movements on the order of 1 inch. The estimated movement should also be considered as the potential amount of tilting of the structure, which could be caused by non-uniform, significant wetting of the subsurface materials below the post-tensioned slab, resulting in potential movement. Failure to maintain soil water content below the slab and to maintain proper drainage around the structure will nullify the movement estimates provided above. 4.3.4 Spread Footings - Design Recommendations Description Value Bearing material Stabilized subgrade or new, properly placed engineered fill. Maximum allowable bearing pressure 1 2,000 psf Lateral earth pressure coefficients 2 On-site soils: Active, Ka = 0.41 Passive, Kp = 2.46 At-rest, Ko = 0.58 Imported fill: Active, Ka = 0.27 Passive, Kp = 3.69 At-Rest, Ko = 0.43 Sliding coefficient 2 On-site soils: µ = 0.37 Import material: µ = 0.56 Moist soil unit weight On-site soils: ܵ = 120 pcf Import material: ܵ = 135 pcf Minimum embedment depth below finished grade 3 30 inches Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 15 Description Value Estimated total movement About 1 inch 1. The recommended maximum allowable bearing pressure assumes any unsuitable fill or soft soils, if encountered, will be stabilized as described in this report. The design bearing pressure applies to a dead load plus ½ design live load condition. The design bearing pressure may be increased by one-third when considering total loads that include wind or seismic conditions. 2. The lateral earth pressure and sliding coefficients are ultimate values and do not include a factor of safety. The foundation designer should include the appropriate factors of safety. 3. For frost protection and to reduce the effects of seasonal moisture variations in the subgrade soils. The minimum embedment depth is for perimeter footings beneath unheated areas and is relative to lowest adjacent finished grade, typically exterior grade. Footings should be proportioned on the basis of equal total dead load pressure to reduce differential movement between adjacent footings. As discussed, total movement resulting from the assumed structural loads is estimated to be on the order of about 1 inch. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction and throughout the life of the structure. Failure to maintain the proper drainage as recommended in the 4.2.7 Grading and Drainage section of this report will nullify the movement estimates provided above. 4.3.5 Spread Footings - Construction Considerations To reduce the potential of “pumping” and softening of the foundation soils at the foundation bearing level and the requirement for corrective work, we suggest the foundation excavation for the proposed buildings be completed remotely with a track-hoe operating outside of the excavation limits. Footings and foundation walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. Unstable subgrade conditions are anticipated as excavations approach the groundwater surface. Unstable surfaces will need to be stabilized prior to backfilling excavations and/or constructing the building foundations. The use of angular rock, recycled concrete and/or gravel pushed or “crowded” into the yielding subgrade is considered suitable means of stabilizing the subgrade. The use of bi-axial or tri-axial geogrid materials in conjunction with gravel or aggregate base course could also be considered and could be more cost effective. Unstable subgrade conditions should be observed by Terracon to assess the subgrade and provide suitable alternatives for stabilization. Foundation excavations should be observed by Terracon. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 16 4.4 Seismic Considerations Code Used Site Classification 2012 International Building Code (IBC) 1 D 2 1. In general accordance with the 2012 International Building Code, Table 1613.5.2. 2. The 2012 International Building Code (IBC) requires a site soil profile determination extending a depth of 100 feet for seismic site classification. The current scope requested does not include the required 100 foot soil profile determination. The borings completed for this project extended to a maximum depth of about 23 feet and this seismic site class definition considers that similar soil and bedrock conditions exist below the maximum depth of the subsurface exploration. Additional exploration to deeper depths could be performed to confirm the conditions below the current depth of exploration. Alternatively, a geophysical exploration could be utilized in order to attempt to justify a more favorable seismic site class; however, we believe this is unlikely. 4.5 Floor Systems If a post-tensioned slab foundation system is selected by the Owner, the foundation system will also function as the floor system for the proposed buildings. If a spread footing foundation system is selected by the Owner, we recommend a slab-on-grade for the floor system for the proposed buildings. If a slab-on-grade floor system is planned as part of the proposed construction, we can provide recommendations for floor slabs. 4.6 Lateral Earth Pressures Reinforced concrete walls with unbalanced backfill levels on opposite sides should be designed for earth pressures at least equal to those indicated in the following table. Earth pressures will be influenced by structural design of the walls, conditions of wall restraint, methods of construction and/or compaction and the strength of the materials being restrained. Two wall restraint conditions are shown. Active earth pressure is commonly used for design of free-standing cantilever retaining walls and assumes wall movement. The "at-rest" condition assumes no wall movement. The recommended design lateral earth pressures do not include a factor of safety and do not provide for possible hydrostatic pressure on the walls. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 17 EARTH PRESSURE COEFFICIENTS Earth Pressure Conditions Coefficient for Backfill Type Equivalent Fluid Density (pcf) Surcharge Pressure, p1 (psf) Earth Pressure, p2 (psf) Active (Ka) Granular - 0.27 Lean Clay - 0.41 37 49 (0.27)S (0.41)S (37)H (49)H At-Rest (Ko) Granular - 0.43 Lean Clay - 0.58 58 70 (0.43)S (0.58)S (58)H (70)H Passive (Kp) Granular - 3.69 Lean Clay - 2.46 375 255 --- --- --- --- Applicable conditions to the above include: „ For active earth pressure, wall must rotate about base, with top lateral movements of about 0.002 H to 0.004 H, where H is wall height; „ For passive earth pressure to develop, wall must move horizontally to mobilize resistance; „ Uniform surcharge, where S is surcharge pressure; „ In-situ soil backfill weight a maximum of 125 pcf; „ Horizontal backfill, compacted between 95 and 98 percent of maximum dry unit weight as determined by ASTM D698; „ Loading from heavy compaction equipment not included; „ No hydrostatic pressures acting on wall; „ No dynamic loading; „ No safety factor included in soil parameters; and „ Ignore passive pressure in frost zone. Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 18 To control hydrostatic pressure behind the walls we recommend that a drain be installed at the foundation walls with a collection pipe leading to a reliable discharge. If this is not possible, then combined hydrostatic and lateral earth pressures should be calculated for lean clay backfill using an equivalent fluid weighing 90 and 100 pcf for active and at-rest conditions, respectively. For granular backfill, an equivalent fluid weighing 85 and 90 pcf should be used for active and at-rest, respectively. These pressures do not include the influence of surcharge, equipment or floor loading, which should be added. Heavy equipment should not operate within a distance closer than the exposed height of retaining walls to prevent lateral pressures more than those provided. 4.8 Pavements 4.8.1 Pavements – Subgrade Preparation On most project sites, the site grading is accomplished relatively early in the construction phase. Fills are typically placed and compacted in a uniform manner. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or rainfall/snow melt. As a result, the pavement subgrade may not be suitable for pavement construction and corrective action will be required. The subgrade should be carefully evaluated at the time of pavement construction for signs of disturbance or instability. We recommend the pavement subgrade be thoroughly proofrolled with a loaded tandem-axle dump truck prior to final grading and paving. All pavement areas should be moisture conditioned and properly compacted to the recommendations in this report immediately prior to paving. 4.8.2 Pavements – Design Recommendations Design of pavements for the project have been based on the procedures outlined in the 1993 Guideline for Design of Pavement Structures prepared by the American Association of State Highway and Transportation Officials (AASHTO) and the Larimer County Urban Area Street Standards (LCUASS). The recommended pavement thicknesses provided in this report are appropriate for the privately-maintained roadways. As required by LCUASS, the Final Pavement Design Report for city-maintained roadways should occur after grading for roadways and utility installation is complete. Terracon can assist with final design of city-maintained roadways following roadway grading and utility installation, upon your request. Samples of the upper clay soils obtained from our borings selected for swell-consolidation testing exhibited slight compression or low swell. Therefore, swell-mitigation of the subgrade materials prior to pavement operations is not required. However, depending upon final grading plans we anticipate stabilization of pavement subgrade will be necessary for this project. Water-soluble sulfate concentrations measured on samples of soils obtained from our borings at this site ranged from 550 to 21,540 parts per million (ppm). These concentrations are above typical acceptable limits to allow for chemical stabilization of subgrade soils. In order to stabilize the subgrade below the proposed pavements planned as part of this project, we recommend utilizing a layer of geogrid below the aggregate base course. Prior to placing a layer of geogrid, Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 19 the roadway should be rough graded and the subgrade should be scarified to a depth of at least 10 inches, moisture conditioned and compacted in-place. Once the subgrade is properly prepared, we recommend placing a single layer of geogrid (Hanes Geo Components TerraGrid® RX 1200 or engineered approved equivalent) over the entire subgrade from back of curb to back of curb. Traffic patterns and anticipated loading conditions were not available at the time that this report was prepared. However, we anticipate that traffic loads will be produced primarily by automobile traffic, occasional delivery and trash removal trucks, and occasional bus traffic. We understand Duff Drive will be classified as an industrial/commercial collector and International Boulevard will be classified as a two-lane arterial road according to the Larimer County Urban Area Street Standards (LCUASS). LCUASS indicates a design Equivalent Single Axel Load (ESAL) of 730,000 should be used for an industrial/commercial collector and a two-lane arterial road. Minimum flexible pavement sections are presented in Table 10-1 of LCUASS. If heavier traffic loading is expected, Terracon should be provided with the information and allowed to review these pavement sections. Asphaltic cement concrete (ACC) pavements can be used for pavements such as drive lanes and parking areas. We recommend portland cement concrete (PCC) pavements for entrance aprons, trash container pads, loading areas, and in any other areas subjected to heavy wheel loads and/or turning traffic. Recommended minimum pavement sections are provided in the table below. Recommended Pavement Thickness (inches) 1 Traffic Area Alternative Asphalt Concrete Portland Cement Concrete Aggregate Base Course Total Surface Thickness Course Base Course Light-Duty (car parking) PCC -- -- 5 12 17 ACC 4 -- -- 12 16 Medium-Duty (drives and loading areas) PCC -- -- 6 12 18 ACC 2 3 -- 12 17 Trash Container Pad PCC -- -- 7 12 19 1 Each pavement section below includes a single layer of geogrid placed below the composite section as described above. Aggregate base course should consist of a blend of sand and gravel which meets strict specifications for quality and gradation. Use of materials meeting Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended for base course. Aggregate Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 20 base course should be placed in lifts not exceeding 6 inches and compacted to a minimum of 95 percent of the maximum dry unit weight as determined by ASTM D698. Asphalt concrete should be composed of a mixture of aggregate, filler and additives (if required) and approved bituminous material. The asphalt concrete should conform to approved mix designs stating the Superpave properties, optimum asphalt content, job mix formula and recommended mixing and placing temperatures. Aggregate used in asphalt concrete should meet particular gradations. Material meeting CDOT Grading S or SX specifications or equivalent is recommended for asphalt concrete. Mix designs should be submitted prior to construction to verify their adequacy. Asphalt material should be placed in maximum 3-inch lifts and compacted within a range of 92 to 96 percent of the theoretical maximum density (ASTM D2041). Where rigid pavements are used, the concrete should be obtained from an approved mix design with the following minimum properties: Properties Value Compressive strength at 28 days 4,000 psi (minimum) Cement type Type I or Type II Entrained air content (%) 5 to 8 Concrete aggregate ASTM C33 and CDOT Section 703 Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation per ACI 325. The location and extent of joints should be based upon the final pavement geometry. Joints should be sealed to prevent entry of foreign material and doweled where necessary for load transfer. We understand others will utilize the information presented in this report to design pavement reinforcement for the proposed concrete pavements. Proper joint spacing will also be required for PCC pavements to prevent excessive slab curling and shrinkage cracking. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. For areas subject to concentrated and repetitive loading conditions such as dumpster pads, truck delivery docks and ingress/egress aprons, we recommend using a portland cement concrete pavement with a thickness of at least 7 inches underlain by at least 6 inches of granular base. Prior to placement of the granular base the areas should be thoroughly proof rolled. For dumpster pads, the concrete pavement area should be large enough to support the container and tipping axle of the refuse truck. Pavement performance is affected by its surroundings. In addition to providing preventive maintenance, the civil engineer should consider the following recommendations in the design and layout of pavements: Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 21 „ Site grades should slope a minimum of 2 percent away from the pavements; „ The subgrade and the pavement surface have a minimum 2 percent slope to promote proper surface drainage; „ Consider appropriate edge drainage and pavement under drain systems; „ Install pavement drainage surrounding areas anticipated for frequent wetting; „ Install joint sealant and seal cracks immediately; „ Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to subgrade soils; and „ Placing compacted, low permeability backfill against the exterior side of curb and gutter. 4.8.3 Pavements – Construction Considerations The placement of a partial pavement thickness for use during construction is not suggested without a detailed pavement analysis incorporating construction traffic. Openings in pavement, such as landscape islands, are sources for water infiltration into surrounding pavements. Water collects in the islands and migrates into the surrounding subgrade soils thereby degrading support of the pavement. This is especially applicable for islands with raised concrete curbs, irrigated foliage, and low permeability near-surface soils. The civil design for the pavements with these conditions should include features to restrict or to collect and discharge excess water from the islands. Examples of features are edge drains connected to the storm water collection system or other suitable outlet and impermeable barriers preventing lateral migration of water such as a cutoff wall installed to a depth below the pavement structure. 4.8.4 Pavements – Maintenance Preventative maintenance should be planned and provided for an ongoing pavement management program in order to enhance future pavement performance. Preventive maintenance consists of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. 5.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable 22 site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as described in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. APPENDIX A FIELD EXPLORATION SITE LOCATION MAP Capstone Cottages of Fort Collins Northeast of N. Lemay Ave. and E. Lincoln Ave. Fort Collins, CO TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY QUADRANGLES INCLUDE: FORT COLLINS, CO (1/1/1984). 1901 Sharp Point Dr Suite C Ft. Collins, CO 20145005 Project Manager: Drawn by: Checked by: Approved by: BCR EDB EDB 1:24,000 3/24/2014 Project No. Scale: File Name: Date: A-1 EDB Exhibit DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES A-2 Project Manager: EXPLORATION PLAN EXHIBIT Drawn By: Check By: Approved By: EDB BCR EDB EDB Project No. Scale: File Name: Date: 20145005 AS SHOWN 3/24/2014 LEGEND Approximate boring location for current study 6 1 Approximate boring location for Previous study (Project No. 20045173) TBM Approximate temporary benchmark location (center of manhole cover) Capstone Cottages of Fort Collins Northeast of N. Lemay Ave. and E. Lincoln Ave. Fort Collins, CO AERIAL PHOTOGRAPHY PROVIDED BY MICROSOFT BING MAPS 1901 Sharp Point Dr Suite C Ft. Collins, CO Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable Exhibit A-3 Field Exploration Description The locations of the supplemental borings were based upon the proposed development shown on the provided site plan and were selected in areas to supplement previously completed subsurface exploration. The supplemental borings were located in the field by measuring from property lines and existing site features. The ground surface elevation was surveyed at each supplemental boring location referencing the temporary benchmark shown on Exhibit A-2 using an engineer’s level. The supplemental borings were drilled with a CME-75 truck-mounted rotary drill rig with hollow- stem augers. During the drilling operations, lithologic logs of the borings were recorded by the field engineer. Disturbed samples were obtained at selected intervals utilizing a 2-inch outside diameter split-spoon sampler and a 3-inch outside diameter ring-barrel sampler. Penetration resistance values were recorded in a manner similar to the standard penetration test (SPT). This test consists of driving the sampler into the ground with a 140-pound hammer free-falling through a distance of 30 inches. The number of blows required to advance the ring-barrel sampler 12 inches (18 inches for standard split-spoon samplers, final 12 inches are recorded) or the interval indicated, is recorded as a standard penetration resistance value (N-value). The blow count values are indicated on the boring logs at the respective sample depths. Ring-barrel sample blow counts are not considered N-values. A CME automatic SPT hammer was used to advance the samplers in the supplemental borings performed on this site. A greater efficiency is typically achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. Published correlations between the SPT values and soil properties are based on the lower efficiency cathead and rope method. This higher efficiency affects the standard penetration resistance blow count value by increasing the penetration per hammer blow over what would be obtained using the cathead and rope method. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report. The standard penetration test provides a reasonable indication of the in-place density of sandy type materials, but only provides an indication of the relative stiffness of cohesive materials since the blow count in these soils may be affected by the moisture content of the soil. In addition, considerable care should be exercised in interpreting the N-values in gravelly soils, particularly where the size of the gravel particle exceeds the inside diameter of the sampler. Groundwater measurements were obtained in the borings at the time of site exploration, and several days after drilling in some of the borings. After completion of drilling, the borings were backfilled with auger cuttings. Some settlement of the backfill may occur and should be repaired as soon as possible. 0.8 3.0 20.0 20.5 23.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, trace gravel and cobbles, dark brown, very stiff POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), trace cobbles, brown, very dense WEATHERED SILTSTONE, rust and light brown SILTSTONE, gray to dark gray, very hard Auger refusal at 23 Feet 28-50/5" 20-37-50/5" N=87/11" 18-34-41 N=75 45-50/2" N=95/8" 28-34-41 N=75 8 5 2 9 10 17 135 27-22-5 100 97.5 80.5 80 77.5 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.59152° Longitude: -105.056213° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 0.8 4.0 20.0 22.0 VEGETATIVE LAYER - 9 inches SILT WITH SAND (ML), trace gravel, brown, stiff POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, coarse to medium grained, brown, medium dense to very dense SILTSTONE, gray to dark gray, very hard Auger refusal at 22 Feet 11-7 8-5-6 N=11 30-23-22 N=45 45-50/2" N=95/8" 50/6" N=50/6" -1.9 11 71 2 9 10 11 114 27-22-5 100 96.5 80.5 78.5 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.590868° Longitude: -105.056762° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/13/2014 BORING LOG NO. 7 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/13/2014 0.8 4.0 20.0 20.3 22.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, trace gravel, dark brown, stiff POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, brown, dense to very dense WEATHERED SILTSTONE, rust and light brown SILTSTONE, dark gray, very hard Auger refusal at 22 Feet 7-6 22-21-17 N=38 16-44-38 N=82 13-22-28 N=50 32-36-50/3" N=86/9" 14 3 13 13 15 98 97.5 94.5 78.5 78 76.5 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.590257° Longitude: -105.055976° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/13/2014 BORING LOG NO. 8 0.8 7.0 15.0 19.5 19.8 22.5 VEGETATIVE LAYER - 9 inches LEAN CLAY, trace gravel, dark brown, medium stiff to stiff POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, brown, medium dense SILTY SAND, fine to medium grained, brown, medium dense WEATHERED SILTSTONE, rust and light brown SILTSTONE, dark gray, very hard Auger refusal at 22.5 Feet 6-7 4-3-3 N=6 20-13-9 N=22 5-10-13 N=23 12-21-50 N=71 27 15 21 18 95 89 81 76.5 76 73.5 2.154 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.589551° Longitude: -105.055967° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling 2/19/14 WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: 0.8 2.0 5.0 20.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND (CL), trace gravel, dark brown SILTY SAND (SM), brown, medium dense POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, brown, dense to very dense Auger refusal at 20 Feet 4-4 2-6-9 N=15 25-47-47 N=94 16-21-27 N=48 41-50/3" N=91/9" 0.01 74 7 24 20 9 11 21 98 37-15-22 NP 95 94 91 76 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.589013° Longitude: -105.056462° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling 2/19/14 WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 10 0.8 7.0 19.3 20.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, dark brown, stiff to very stiff POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, brown, dense to very dense SILTSTONE, dark gray, very hard Auger refusal at 20 Feet 6-5 3-6-17 N=23 10-10-22 N=32 36-50/3" N=86/9" 27-50/6" N=77 17 17 15 11 16 103 98.5 92 80 79 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.590774° Longitude: -105.054798° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/13/2014 BORING LOG NO. 11 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/13/2014 0.8 4.0 14.5 15.0 17.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND (CL), dark brown, stiff POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), brown, medium dense to dense WEATHERED SILTSTONE, rust and light brown SILTSTONE, dark gray, very hard Auger refusal at 17 Feet 6-4 7-15-14 N=29 14-14-24 N=38 42-20-50 N=70 0.1 72 7 29 8 12 19 93 49-20-29 NP 93 90 79.5 79 77 0.467 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.590068° Longitude: -105.053983° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 0.8 4.0 16.0 21.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, trace gravel, dark brown, soft POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, coarse to medium grained, brown, medium dense to dense SILTSTONE, gray to dark gray, very hard Auger refusal at 21 Feet 1-2 10-11-16 N=27 10-12-10 N=22 9-20-28 N=48 50/6" N=50/6" 24 9 17 13 18 95 93 90 78 73 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.589281° Longitude: -105.054169° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling 2/19/14 WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 13 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. 0.8 3.0 14.5 19.5 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, dark brown, medium stiff POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), trace cobbles, coarse to medium grained, brown, medium dense to very dense SILTSTONE, dark gray, hard to very hard Auger refusal at 19.5 Feet 3-2 12-14-15 N=29 21-28-37 N=65 11-38-50/4" N=88/10" 50/6" N=50/6" 6 5 9 15 18 NP 91.5 89.5 78 73 0 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.589179° Longitude: -105.052875° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 14 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. 0.8 2.0 19.0 22.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, trace gravel, dark brown POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, brown, medium dense to very dense SILTSTONE, dark gray, hard to very hard Auger refusal at 22 Feet 12-13 17-22-15 N=37 17-28-27 N=55 30-50/4" N=80/10" 13-50/5" N=63/11" 1 7 9 11 16 92 93 92 75 72 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.588176° Longitude: -105.053513° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 15 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/12/2014 0.8 2.0 17.0 18.0 VEGETATIVE LAYER - 9 inches LEAN CLAY WITH SAND, trace gravel, dark brown POORLY GRADED SAND WITH SILT AND GRAVEL, trace cobbles, fine to coarse grained, brown, dense to very dense SILTSTONE, dark gray, very hard Auger refusal at 18 Feet 47-50/5" 23-22-14 N=36 20-19-35 N=54 25-50/6" N=75 1 5 9 12 125 94.5 93 78 77 0.055 See Exhibit A-2 Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic LOCATION DEPTH Latitude: 40.588655° Longitude: -105.054737° GRAPHIC LOG NE of South Lemay and E Lincoln Fort Collins, Colorado SITE: While drilling WATER LEVEL OBSERVATIONS PROJECT: Capstone Cottages of Fort Collins Page 1 of 1 Advancement Method: 4.25-inch hollow stem auger Abandonment Method: Borings backfilled with soil cuttings upon completion. 1901 Sharp Point Drive, Suite C Fort Collins, Colorado Notes: Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 16 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/12/2014 Exhibit: A-19 See Exhibit A-3 for description of field APPENDIX B LABORATORY TESTING Geotechnical Engineering Report Capstone Cottages of Fort Collins Ŷ Fort Collins, Colorado March 28, 2014 Ŷ Terracon Project No. 20145005 Responsive Ŷ Resourceful Ŷ Reliable Exhibit B-1 Laboratory Testing Description The soil and bedrock samples retrieved during the field exploration were returned to the laboratory for observation by the project geotechnical engineer. At that time, the field descriptions were reviewed and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Laboratory tests were conducted on selected soil and bedrock samples. The results of these tests are presented on the boring logs and in this appendix. The test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. The laboratory tests were performed in general accordance with applicable locally accepted standards. Soil samples were classified in general accordance with the Unified Soil Classification System described in Appendix C. Rock samples were visually classified in general accordance with the description of rock properties presented in Appendix C. „ Water content „ Plasticity index „ Grain-size distribution „ Consolidation/swell „ Water-soluble sulfate content „ Dry density „ pH APPENDIX C SUPPORTING DOCUMENTS Exhibit: C-1 Unconfined Compressive Strength Qu, (tsf) 0.25 to 0.50 1.00 to 2.00 > 4.00 less than 0.25 0.50 to 1.00 2.00 to 4.00 Non-plastic Low Medium High DESCRIPTION OF SYMBOLS AND ABBREVIATIONS Hand Penetrometer Torvane Dynamic Cone Penetrometer Photo-Ionization Detector Organic Vapor Analyzer SAMPLING WATER LEVEL FIELD TESTS (HP) (T) (DCP) (PID) (OVA) GENERAL NOTES Over 12 in. (300 mm) 12 in. to 3 in. (300mm to 75mm) 3 in. to #4 sieve (75mm to 4.75 mm) #4 to #200 sieve (4.75mm to 0.075mm Passing #200 sieve (0.075mm) Particle Size < 5 5 - 12 > 12 Percent of Dry Weight Descriptive Term(s) of other constituents RELATIVE PROPORTIONS OF FINES 0 1 - 10 11 - 30 > 30 Plasticity Index Soil classification is based on the Unified Soil 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. LOCATION AND ELEVATION NOTES Percent of Dry Weight Major Component of Sample UNIFIED SOIL CLASSIFICATION SYSTEM Exhibit C-2 Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification Group Symbol Group Name B Coarse Grained Soils: More than 50% retained on No. 200 sieve Gravels: More than 50% of coarse fraction retained on No. 4 sieve Clean Gravels: Less than 5% fines C 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 Gravels with Fines: More than 12% fines C Fines classify as ML or MH GM Silty gravel F,G,H Fines classify as CL or CH GC Clayey gravel F,G,H Sands: 50% or more of coarse fraction passes No. 4 sieve Clean Sands: Less than 5% fines D 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 Sands with Fines: More than 12% fines D Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I Fine-Grained Soils: 50% or more passes the No. 200 sieve Silts and Clays: Liquid limit less than 50 Inorganic: PI  7 and plots on or above “A” line J CL Lean clay K,L,M PI  4 or plots below “A” line J ML Silt K,L,M Organic: Liquid limit - oven dried  0.75 OL Organic clay K,L,M,N Liquid limit - not dried Organic silt K,L,M,O Silts and Clays: Liquid limit 50 or more 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  0.75 OH Organic clay K,L,M,P Liquid limit - not dried Organic silt K,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-inch (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. DESCRIPTION OF ROCK PROPERTIES Exhibit C-3 WEATHERING Fresh Rock fresh, crystals bright, few joints may show slight staining. Rock rings under hammer if crystalline. Very slight Rock generally fresh, joints stained, some joints may show thin clay coatings, crystals in broken face show bright. Rock rings under hammer if crystalline. Slight Rock generally fresh, joints stained, and discoloration extends into rock up to 1 in. Joints may contain clay. In granitoid rocks some occasional feldspar crystals are dull and discolored. Crystalline rocks ring under hammer. Moderate Significant portions of rock show discoloration and weathering effects. In granitoid rocks, most feldspars are dull and discolored; some show clayey. Rock has dull sound under hammer and shows significant loss of strength as compared with fresh rock. Moderately severe All rock except quartz discolored or stained. In granitoid rocks, all feldspars dull and discolored and majority show kaolinization. Rock shows severe loss of strength and can be excavated with geologist’s pick. Severe All rock except quartz discolored or stained. Rock “fabric” clear and evident, but reduced in strength to strong soil. In granitoid rocks, all feldspars kaolinized to some extent. Some fragments of strong rock usually left. Very severe All rock except quartz discolored or stained. Rock “fabric” discernible, but mass effectively reduced to “soil” with only fragments of strong rock remaining. Complete Rock reduced to ”soil”. Rock “fabric” not discernible or discernible only in small, scattered locations. Quartz may be present as dikes or stringers. HARDNESS (for engineering description of rock – not to be confused with Moh’s scale for minerals) Very hard Cannot be scratched with knife or sharp pick. Breaking of hand specimens requires several hard blows of geologist’s pick. Hard Can be scratched with knife or pick only with difficulty. Hard blow of hammer required to detach hand specimen. Moderately hard Can be scratched with knife or pick. Gouges or grooves to ¼ in. deep can be excavated by hard blow of point of a geologist’s pick. Hand specimens can be detached by moderate blow. Medium Can be grooved or gouged 1/16 in. deep by firm pressure on knife or pick point. Can be excavated in small chips to pieces about 1-in. maximum size by hard blows of the point of a geologist’s pick. Soft Can be gouged or grooved readily with knife or pick point. Can be excavated in chips to pieces several inches in size by moderate blows of a pick point. Small thin pieces can be broken by finger pressure. Very soft Can be carved with knife. Can be excavated readily with point of pick. Pieces 1-in. or more in thickness can be broken with finger pressure. Can be scratched readily by fingernail. Joint, Bedding, and Foliation Spacing in Rock a Spacing Joints Bedding/Foliation Less than 2 in. Very close Very thin 2 in. – 1 ft. Close Thin 1 ft. – 3 ft. Moderately close Medium 3 ft. – 10 ft. Wide Thick More than 10 ft. Very wide Very thick a. Spacing refers to the distance normal to the planes, of the described feature, which are parallel to each other or nearly so. Rock Quality Designator (RQD) a Joint Openness Descriptors RQD, as a percentage Diagnostic description Openness Descriptor Exceeding 90 Excellent No Visible Separation Tight 90 – 75 Good Less than 1/32 in. Slightly Open 75 – 50 Fair 1/32 to 1/8 in. Moderately Open 50 – 25 Poor 1/8 to 3/8 in. Open Less than 25 Very poor 3/8 in. to 0.1 ft. Moderately Wide a. RQD (given as a percentage) = length of core in pieces Greater than 0.1 ft. Wide 4 in. and longer/length of run. References: American Society of Civil Engineers. Manuals and Reports on Engineering Practice - No. 56. Subsurface Investigation for Design and Construction of Foundations of Buildings. New York: American Society of Civil Engineers, 1976. U.S. Department of the Interior, Bureau of Reclamation, Engineering Geology Field Manual. Exhibit C-4 LABORATORY TEST SIGNIFICANCE AND PURPOSE Test Significance Purpose California Bearing Ratio Used to evaluate the potential strength of subgrade soil, subbase, and base course material, including recycled materials for use in road and airfield pavements. Pavement Thickness Design Consolidation Used to develop an estimate of both the rate and amount of both differential and total settlement of a structure. Foundation Design Direct Shear Used to determine the consolidated drained shear strength of soil or rock. Bearing Capacity, Foundation Design, and Slope Stability Dry Density Used to determine the in-place density of natural, inorganic, fine-grained soils. Index Property Soil Behavior Expansion Used to measure the expansive potential of fine-grained soil and to provide a basis for swell potential classification. Foundation and Slab Design Gradation Used for the quantitative determination of the distribution of particle sizes in soil. Soil Classification Liquid & Plastic Limit, Plasticity Index Used as an integral part of engineering classification systems to characterize the fine-grained fraction of soils, and to specify the fine-grained fraction of construction materials. Soil Classification Permeability Used to determine the capacity of soil or rock to conduct a liquid or gas. Groundwater Flow Analysis pH Used to determine the degree of acidity or alkalinity of a soil. Corrosion Potential Resistivity Used to indicate the relative ability of a soil medium to carry electrical currents. Corrosion Potential R-Value Used to evaluate the potential strength of subgrade soil, subbase, and base course material, including recycled materials for use in road and airfield pavements. Pavement Thickness Design Soluble Sulfate Used to determine the quantitative amount of soluble sulfates within a soil mass. Corrosion Potential Exhibit C-5 REPORT TERMINOLOGY (Based on ASTM D653) Allowable Soil Bearing Capacity The recommended maximum contact stress developed at the interface of the foundation element and the supporting material. Alluvium Soil, the constituents of which have been transported in suspension by flowing water and subsequently deposited by sedimentation. Aggregate Base Course A layer of specified material placed on a subgrade or subbase usually beneath slabs or pavements. Backfill A specified material placed and compacted in a confined area. Bedrock A natural aggregate of mineral grains connected by strong and permanent cohesive forces. Usually requires drilling, wedging, blasting or other methods of extraordinary force for excavation. Bench A horizontal surface in a sloped deposit. Caisson (Drilled Pier or Shaft) A concrete foundation element cast in a circular excavation which may have an enlarged base. Sometimes referred to as a cast-in-place pier or drilled shaft. Coefficient of Friction A constant proportionality factor relating normal stress and the corresponding shear stress at which sliding starts between the two surfaces. Colluvium Soil, the constituents of which have been deposited chiefly by gravity such as at the foot of a slope or cliff. Compaction The densification of a soil by means of mechanical manipulation Concrete Slab-on- Grade A concrete surface layer cast directly upon a base, subbase or subgrade, and typically used as a floor system. Differential Movement Unequal settlement or heave between, or within foundation elements of structure. Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall. ESAL Equivalent Single Axle Load, a criteria used to convert traffic to a uniform standard, (18,000 pound axle loads). Engineered Fill Specified material placed and compacted to specified density and/or moisture conditions under observations of a representative of a geotechnical engineer. Equivalent Fluid A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral support presumed to be equivalent to that produced by the actual soil. This simplified approach is valid only when deformation conditions are such that the pressure increases linearly with depth and the wall friction is neglected. Existing Fill (or Man-Made Fill) Materials deposited throughout the action of man prior to exploration of the site. Existing Grade The ground surface at the time of field exploration. Exhibit C-6 REPORT TERMINOLOGY (Based on ASTM D653) Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of moisture. Finished Grade The final grade created as a part of the project. Footing A portion of the foundation of a structure that transmits loads directly to the soil. Foundation The lower part of a structure that transmits the loads to the soil or bedrock. Frost Depth The depth at which the ground becomes frozen during the winter season. Grade Beam A foundation element or wall, typically constructed of reinforced concrete, used to span between other foundation elements such as drilled piers. Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock. Heave Upward movement. Lithologic The characteristics which describe the composition and texture of soil and rock by observation. Native Grade The naturally occurring ground surface. Native Soil Naturally occurring on-site soil, sometimes referred to as natural soil. Optimum Moisture Content The water content at which a soil can be compacted to a maximum dry unit weight by a given compactive effort. Perched Water Groundwater, usually of limited area maintained above a normal water elevation by the presence of an intervening relatively impervious continuous stratum. Scarify To mechanically loosen soil or break down existing soil structure. Settlement Downward movement. Skin Friction (Side Shear) The frictional resistance developed between soil and an element of the structure such as a drilled pier. Soil (Earth) Sediments or other unconsolidated accumulations of solid particles produced by the physical and chemical disintegration of rocks, and which may or may not contain organic matter. Strain The change in length per unit of length in a given direction. Stress The force per unit area acting within a soil mass. Strip To remove from present location. Subbase A layer of specified material in a pavement system between the subgrade and base course. Subgrade The soil prepared and compacted to support a structure, slab or pavement system. Unconfined Compression To obtain the approximate compressive strength of soils that possess sufficient cohesion to permit testing in the unconfined state. Bearing Capacity Analysis for Foundations Water Content Used to determine the quantitative amount of water in a soil mass. Index Property Soil Behavior 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 = 10 60 2 30 D x D (D ) F If soil contains  15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. H If 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. Trace With Modifier RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Trace With Modifier DESCRIPTIVE SOIL CLASSIFICATION Boulders Cobbles Gravel Sand Silt or Clay Descriptive Term(s) of other constituents < 15 15 - 29 > 30 Term PLASTICITY DESCRIPTION Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations. Water Level After a Specified Period of Time Water Level After a Specified Period of Time Water Initially Encountered Modified Dames & Moore Ring Sampler Standard Penetration Test Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area. STRENGTH TERMS BEDROCK Loose Medium Dense Dense 0 - 3 4 - 9 10 - 29 30 - 50 7 - 18 19 - 58 Very Soft Soft Medium-Stiff Stiff Very Stiff Standard Penetration or N-Value Blows/Ft. 2 - 4 4 - 8 8 - 15 < 3 5 - 9 19 - 42 > 42 30 - 49 50 - 89 20 - 29 Medium Hard Very Dense RELATIVE DENSITY OF COARSE-GRAINED SOILS Descriptive Term (Density) Very Loose > 50 Ring Sampler Blows/Ft. 0 - 6 59 - 98 > 99 Descriptive Term (Consistency) Hard 0 - 1 Ring Sampler Blows/Ft. 3 - 4 10 - 18 Ring Sampler Blows/Ft. < 30 90 - 119 Standard Penetration or N-Value Blows/Ft. Descriptive Term (Consistency) Weathered Firm Very Hard CONSISTENCY OF FINE-GRAINED SOILS (More than 50% retained on No. 200 sieve.) Density determined by Standard Penetration Resistance (50% or more passing the No. 200 sieve.) Consistency determined by laboratory shear strength testing, field visual-manual procedures or standard penetration resistance Standard Penetration or N-Value Blows/Ft. _ 15 - 30 > 30 > 119 < 20 30 - 49 50 - 79 >79 Hard procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 95.1 (Ft.) DEPTH (Ft.) 5 10 15 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Exhibit: A-18 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 93.9 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Boring Completed: 2/12/2014 Exhibit: A-17 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 92.5 (Ft.) DEPTH (Ft.) 5 10 15 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Boring Completed: 2/12/2014 Exhibit: A-16 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 94 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) BORING LOG NO. 12 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/12/2014 Exhibit: A-15 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 93.9 (Ft.) DEPTH (Ft.) 5 10 15 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Exhibit: A-14 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 99.2 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/12/2014 Exhibit: A-13 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 95.8 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Project No.: 20145005 Drill Rig: CME-75 Boring Started: 2/12/2014 BORING LOG NO. 9 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/12/2014 Exhibit: A-12 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 95.8 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/13/2014 Exhibit: A-11 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 98.5 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Exhibit: A-10 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 100.7 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%) Boring Started: 2/13/2014 BORING LOG NO. 6 CLIENT: Capstone Collegiate Communities, LLC Birmingham, Alabama Driller: Drilling Engineers, Inc. Boring Completed: 2/13/2014 Exhibit: A-9 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20145005.GPJ TERRACON2012.GDT 3/28/14 FIELD TEST RESULTS SWELL (%) PERCENT FINES WATER CONTENT (%) DRY UNIT WEIGHT (pcf) ATTERBERG LIMITS LL-PL-PI ELEVATION (Ft.) Surface Elev.: 100.7 (Ft.) DEPTH (Ft.) 5 10 15 20 WATER LEVEL OBSERVATIONS SAMPLE TYPE RECOVERY (In.) SULFATES (%)