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Home My WebLink About221 E. MOUNTAIN AVENUE - BASIC DEVELOPMENT REVIEW - BDR160011 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGeotechnical Engineering Report 221 East Mountain Office Building 221 East Mountain Avenue Fort Collins, Colorado April 20, 2016 Terracon Project No. 20165029 Prepared for: MAV Development Co Ann Arbor, Michigan Prepared by: Terracon Consultants, Inc. Fort Collins, Colorado TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................ i 1.0 INTRODUCTION ............................................................................................................ 1 2.0 PROJECT INFORMATION ............................................................................................ 1 2.1 Project Description .............................................................................................. 1 2.2 Site Location and Description ............................................................................. 2 3.0 SUBSURFACE CONDITIONS ....................................................................................... 2 3.1 Geology .............................................................................................................. 2 3.2 Typical Subsurface Profile .................................................................................. 2 3.3 Laboratory Testing .............................................................................................. 3 3.4 Corrosion Protection (Water-Soluble Sulfates) .................................................... 3 3.5 Groundwater ....................................................................................................... 3 3.6 Pressuremeter Testing ........................................................................................ 4 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ..................................... 4 4.1 Geotechnical Considerations .............................................................................. 4 4.1.1 Groundwater and Caving Soils ................................................................ 4 4.1.2 Foundation and Floor System Recommendations ................................... 5 4.2 Earthwork ........................................................................................................... 5 4.2.1 Site Preparation........................................................................................ 5 4.2.2 Demolition ............................................................................................... 5 4.2.3 Excavation ............................................................................................... 6 4.2.4 Subgrade Preparation .............................................................................. 6 4.2.5 Fill Materials and Placement ..................................................................... 7 4.2.6 Compaction Requirements ....................................................................... 8 4.2.7 Utility Trench Backfill ............................................................................... 8 4.2.8 Grading and Drainage .............................................................................. 9 4.3 Foundations .......................................................................................................10 4.3.1 Drilled Piers Bottomed in Bedrock - Design Recommendations ..............10 4.3.2 Drilled Piers Bottomed in Bedrock - Construction Considerations ...........11 4.3.3 Spread Footings - Design Recommendations .........................................11 4.3.4 Spread Footings - Construction Considerations ......................................12 4.4 Seismic Considerations......................................................................................13 4.5 Floor Systems ....................................................................................................13 4.5.1 Floor System - Design Recommendations ..............................................13 4.5.2 Floor Systems - Construction Considerations .........................................14 4.6 Elevator Pit ........................................................................................................14 4.6.1 Elevator Pit Design Recommendations ...................................................14 4.6.2 Elevator Pit Construction Considerations ................................................15 4.7 Pavements .........................................................................................................15 4.7.1 Pavements – Subgrade Preparation .......................................................15 4.7.2 Pavements – Design Recommendations ................................................16 4.7.3 Pavements – Construction Considerations .............................................18 4.7.4 Pavements – Maintenance .....................................................................18 5.0 GENERAL COMMENTS ...............................................................................................18 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-7 Boring Logs Exhibits A-8 to A-10 Pressuremeter Test Results Appendix B – LABORATORY TESTING Exhibit B-1 Laboratory Testing Description Exhibit B-2 Atterberg Limits Test Results Exhibit B-3 Grain-size Distribution Test Results Exhibit B-4 Water-soluble Sulfate 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 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable i EXECUTIVE SUMMARY A geotechnical investigation has been performed for the proposed office building to be constructed at 221 East Mountain Avenue in Fort Collins, Colorado. Four (4) borings, presented as Exhibits A-4 through A-7 and designated as Boring No. 1 through Boring No. 4, were performed to depths of approximately 15.3 to 35 feet below existing site grades. This report specifically addresses the recommendations for the proposed office building. Borings performed in these areas are for informational purposes and will be utilized by others. Based on the information obtained from our subsurface exploration, the site can be developed for the proposed project. However, the following geotechnical considerations were identified and will need to be considered:  Borings completed as part of our geotechnical study at this site were performed in the existing parking lot and pavement areas surrounding the existing structure currently occupying the site. Existing pavement materials encountered in our borings generally consisted of 3 to 8 inches of asphalt, concrete or asphalt overlying concrete.  Subsurface conditions encountered below the existing pavement materials generally consist of about 2 to 3 feet of sand with varying amounts of clay over about 10 feet of well graded sand with varying amounts of gravel and cobbles. Sandstone bedrock was encountered below the sands with gravels and cobbles at depths ranging from about 13 to 14 feet below existing site grades and extended to the maximum depths explored.  Groundwater was encountered in two of the borings at depths of about 12 to 13 feet below existing ground surface during drilling and approximately one day after drilling. Groundwater levels can and should be expected to fluctuate with varying seasonal and weather conditions, irrigation on or adjacent to the site and with fluctuations in nearby water features.  Demolition of the existing building currently occupying the site should include complete removal of all foundation systems, pavements, floor slabs, and exterior flatwork within the proposed construction area. Discussions regarding re-use of the asphalt and concrete as recycled materials during the new construction are presented in the report.  The proposed building may be supported on either a drilled pier foundation system bottomed in bedrock or a shallow footing foundations bearing on the dense native soil or on newly placed engineered fill. Drilled piers will require temporary casing for proper construction. Heavy-duty pier drilling equipment will also likely be required to penetrate the very hard sandstone identified below the site.  A slab-on-grade floor system is recommended for the proposed building. Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable ii  The amount of movement of foundations, floor slabs, pavements, etc. will be related to the wetting of underlying supporting soils. Therefore, it is imperative the recommendations discussed in the 4.2.8 Grading and Drainage section of this report be followed to reduce potential movement.  The 2012 International Building Code, Table 1613.5.2 IBC seismic site classification for this site is C.  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 ■ Resourceful ■ Reliable 1 GEOTECHNICAL ENGINEERING REPORT 221 East Mountain Office Building 221 East Mountain Avenue Fort Collins, Colorado Terracon Project No. 20165029 April 20, 2016 1.0 INTRODUCTION This report presents the results of our geotechnical engineering services performed for the proposed office building to be located at 221 East Mountain Avenue in Fort Collins, Colorado (Exhibit A-1). 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 the initial site visit, the advancement of four test borings to depths ranging from approximately 15.3 to 35 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. 2.0 PROJECT INFORMATION 2.1 Project Description Item Description Site layout Refer to the Exploration Plan (Exhibit A-2 in Appendix A) Structures We understand the new retail/office building will be a four-story approximately 70,000 gross square foot building. Building construction We understand the building will be steel-framed with a slab-on-metal deck and a slab-on-grade main level. Maximum loads Column loads: 150 – 500 kips (provided) Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 2 Item Description Below-grade areas We understand that no below-grade areas are planned. However, the proposed elevator pit will likely extend several feet below grade. Traffic loading NAPA Traffic Class: (assumed) Automobile Parking Areas: Class I Truck traffic and main drives Class II 2.2 Site Location and Description Item Description Location The project site is located at 221 East Mountain Avenue in Fort Collins, Colorado. Existing site features The site is partially covered by an existing building and parking lot with some landscaped vegetation around the perimeter. Surrounding developments To the west and south of the site are commercial buildings, to the north of the site is East Mountain Avenue and to the east of the site is Mathews Street. Current ground cover The ground cover outside the existing building envelope is mostly asphaltic concrete with some concrete pavement and flatwork. Existing topography The site is relatively flat. 3.0 SUBSURFACE CONDITIONS 3.1 Geology The Pleistocene Age Slocum Alluvium comprises the site surficial geologic materials (Colton, 19781). These materials generally consist of cobbles and gravels up to 20 feet thick. Materials are typically well-rounded and of igneous and metamorphic origin, although some are sedimentary (Colton, 19781). The underlying bedrock consists of the Hygiene Sandstone Member of the Upper Cretaceous Age Pierre Shale. A hard, glauconitic, ridge-forming sandstone makes up the upper portions of this member and has been reported to range in thickness between 600 and 800 feet (Colton, 19781). 3.2 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 1 Colton, Roger B., 1978, Geologic Map of the Boulder-Fort Collins-Greeley Area, Colorado, United States Geologic Survey, Map I-855-G. Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 3 location of changes in soil types; in-situ, the transition between materials may be gradual. Based on the results of the borings, subsurface conditions on the project site can be generalized as follows: Material Description Approximate Depth to Bottom of Stratum (feet) Consistency/Density/Hardness Asphalt and concrete About 3 to 8 inches below existing site grades. -- Sand with varying amount of clay About 2 to 4 feet below existing site grades. Loose to dense Well graded sand with varying amounts of gravel and cobbles About 13 feet below existing site grades. Only found in Boring Nos. 1, 2 and 3. Medium dense to very dense Silty clayey sand with gravel and cobbles About 14 feet below existing site grades. Only found in Boring No. 4. Very dense Sandstone bedrock To the maximum depth of exploration of about 35 feet. Very hard 3.3 Laboratory Testing Samples of on-site soils selected for plasticity testing exhibited low to moderate plasticity with liquid limits ranging from 23 to 28 and plasticity indices ranging from 6 to 9. Laboratory test results are presented in Appendix B. 3.4 Corrosion Protection (Water-Soluble Sulfates) Results of water-soluble sulfate testing indicate that ASTM Type I or II portland cement should be specified for all project concrete on and below grade. Foundation concrete should be designed for low sulfate exposure in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. 3.5 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 Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 4 Boring Number Depth to groundwater while drilling, ft. Depth to groundwater 1 day after drilling, ft. Elevation of groundwater 1 day after drilling, ft. 1 13 12.6 4962.1 2 Not encountered -- -- 3 Not encountered -- -- 4 12 Caving in borehole -- These observations represent groundwater conditions at the time of and shortly after 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. 3.6 Pressuremeter Testing Pressuremeter testing was performed within the sandstone bedrock at two (2) of the boring locations (PMT 1 and PMT 2, as shown on Exhibit A-2). Two (2) tests were performed at PMT 1 and one (1) test was performed at PMT 2 at varying depths within the bedrock strata. Pressuremeter testing was performed using a cylindrical probe with an inner rubber membrane and an outer protective sheath that were inflated using fluid pressurized against the sidewalls of the borings at depths determined in the field during completion of the borings. The deformation of the bearing strata was measured periodically while increasing pressures until the bedrock failed in shear. Pressuremeter test results are presented on Exhibits A-8 through A-10 in Appendix A. Using the data collected during pressuremeter testing, in-situ strength parameters were calculated including Young’s Moduli, limit pressures, and Menard deformation moduli. Using these values, the bedrock was modeled more accurately than conventional methods, and values for deep foundation design and construction criteria were calculated. 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 Groundwater and Caving Soils As previously stated, groundwater was measured at depths ranging from about 12 to 13 feet below existing site grades. Although no below-grade areas are planned for the proposed building other than anticipated elevator pit(s), groundwater may impact installation of deep utilities. Caving Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 5 soils and groundwater will impact construction of drilled pier foundations requiring the use of temporary casing and placement of concrete using tremie or other similar methods. 4.1.2 Foundation and Floor System Recommendations The proposed building may be supported on either a drilled pier foundation system bottomed in bedrock or a spread footing foundation system bearing on properly prepared on-site soils or properly placed imported fill. We recommend a slab-on-grade for the interior floor system of the proposed building. Even when bearing on properly prepared soils, movement of the slab-on- grade floor system is possible should the subgrade soils undergo an increase in moisture content. We estimate movement of about 1 inch is possible. If the owner cannot accept the risk of slab movement, a structural floor should be used. 4.2 Earthwork The following presents recommendations for site preparation, demolition, 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 removal and recompaction of existing fill materials likely to be encountered during demolition, 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 asphalt, concrete or vegetation and any other deleterious materials from the proposed construction area. Stripped organic materials should be wasted from the site or used to re-vegetate landscaped areas or exposed slopes 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. 4.2.2 Demolition Demolition of the existing on-site building should include complete removal of all foundation systems, below-grade structural elements, pavements, and exterior flat work within the proposed construction area. This should include removal of any utilities to be abandoned along with any loose utility trench backfill or loose backfill found adjacent to existing foundations. All materials derived from the demolition of existing structures and pavements should be removed from the site. The types of foundation systems supporting the existing on-site building are not known. If some or all of the existing buildings are supported by drilled piers, the existing piers should be truncated a minimum depth of 3 feet below areas of planned new construction. Consideration could be given to re-using the asphalt and concrete provided the materials are processed and uniformly blended with the on-site soils. Asphalt and/or concrete materials should Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 6 be processed to a maximum size of 2-inches and blended at a ratio of 30 percent asphalt/concrete to 70 percent of on-site soils. 4.2.3 Excavation It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. Excavations into the on-site soils will encounter weak and/or saturated soil conditions with possible caving conditions. Excavation penetrating the bedrock (if required) may require the use of specialized heavy-duty equipment to advance the excavation and facilitate rock break-up and removal. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. 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 fills or 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. 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. 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 4.2.4 Subgrade Preparation After completion of site preparation, the top 8 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. Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 7 In addition, large cobbles may be encountered beneath floor slabs or foundation areas if footings are selected as the foundation type for the proposed building. Such conditions could create point loads on the bottom of floor slabs and foundations, increasing the risk potential for differential movement and cracking. If such conditions are encountered in the excavations, the 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 pad 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. Use of geotextile or cement could also be considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction. Lightweight excavation equipment may also be used to reduce subgrade pumping. 4.2.5 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 pad and pavement subgrade. It should be noted that clayey sand will 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 50 (max.) Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 8 Soil Properties Values Liquid Limit 35 (max.) Plastic Limit 6 (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. 4.2.6 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 AASHTO T180 Moisture content -3 to +3 % 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. 4.2.7 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 structure 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 building should be effectively sealed to restrict water intrusion and flow Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 9 through the trenches that could migrate below the building. We recommend constructing an effective clay “trench plug” that extends at least 5 feet out from the face of the building exterior. The plug material should consist of clay compacted at a water content at or above the soil’s 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. 4.2.8 Grading and Drainage All grades must be adjusted to provide effective drainage away from the proposed building and existing buildings surrounding the site 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 structure (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 building, 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 building. 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 building 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 structure, care should be taken that joints are properly sealed and maintained to prevent the infiltration of surface water. Planters located adjacent to structure 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 structure 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 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 10 4.3 Foundations The proposed building can be supported by either a drilled pier foundation system bottomed in bedrock or a shallow, spread footing foundation system. Design recommendations for foundations for the proposed structure and related structural elements are presented in the following paragraphs. 4.3.1 Drilled Piers Bottomed in Bedrock - Design Recommendations Description Value Estimated pier length 16 to 20 feet Minimum pier diameter 18 inches Minimum bedrock embedment 1 6 feet Maximum allowable end-bearing pressure 80,000 psf Allowable skin friction (for portion of pier embedded into bedrock 3,500 psf 1. Drilled piers should be embedded into hard or very hard bedrock materials. Actual structural loads and pier diameters may dictate embedment deeper than the recommended minimum penetration. Piers should be considered to work in group action if the horizontal spacing is less than three pier diameters. A minimum practical horizontal clear spacing between piers of at least three diameters should be maintained, and adjacent piers should bear at the same elevation. The capacity of individual piers must be reduced when considering the effects of group action. Capacity reduction is a function of pier spacing and the number of piers within a group. If group action analyses are necessary, capacity reduction factors can be provided for the analyses. To satisfy forces in the horizontal direction using LPILE, piers may be designed for the following lateral load criteria: Parameters Sand Sandstone Bedrock LPILE soil type Sand (Reese) Sand (Reese) Effective unit weight (pcf) above groundwater 120 125 Effective unit weight (pcf) below groundwater 60 125 (perched) Average angle of internal friction,  (degrees) 35 40 Coefficient of subgrade reaction, k (pci)* 90 225 1. For purposes of LPILE analysis, assume a groundwater depth of about 12 feet below existing ground surface (approximately Elev. 4963 feet). Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 11 4.3.2 Drilled Piers Bottomed in Bedrock - Construction Considerations Very hard sandstone bedrock was encountered below the entire site. It is possible drilling to design depth may require specialized drilling equipment for completion of pier holes into the very hard bedrock layers. Groundwater/caving soil conditions indicate that temporary steel casing may be required to properly drill and clean piers prior to concrete placement. Groundwater should be removed from each pier hole prior to concrete placement. Pier concrete should be placed immediately after completion of drilling and cleaning. If pier concrete cannot be placed in dry conditions, a tremie should be used for concrete placement. Free-fall concrete placement in piers will only be acceptable if provisions are taken to avoid striking the concrete on the sides of the hole or reinforcing steel. The use of a bottom-dump hopper, or an elephant's trunk discharging near the bottom of the hole where concrete segregation will be minimized, is recommended. Due to potential sloughing and raveling, foundation concrete quantities may exceed calculated geometric volumes. Casing should be withdrawn in a slow continuous manner maintaining a sufficient head of concrete to prevent infiltration of water or caving soils or the creation of voids in pier concrete. Pier concrete should have a relatively high fluidity when placed in cased pier holes or through a tremie. Pier concrete with slump in the range of 5 to 7 inches is recommended. We recommend the sides of each pier should be mechanically roughened in the sandstone bearing strata. This should be accomplished by a roughening tooth placed on the auger. Shaft bearing surfaces must be cleaned prior to concrete placement. A representative of Terracon should observe the bearing surface and shaft configuration. 4.3.3 Spread Footings - Design Recommendations As an alternative, we believe the proposed building can be constructed on spread footing foundations bearing on properly prepared on-site soils or newly placed engineered fill. We understand column loads may be as large as 500 kips which could result in very large footing pad sizes. However, subsurface conditions below this site are conducive to support of spread footing foundations and we believe they are a viable foundation alternative. Description Values Bearing material Properly prepared on-site soil or new, properly placed engineered fill. Maximum allowable bearing pressure 1 3,500 psf Lateral earth pressure coefficients 2 Active, Ka = 0.27 Passive, Kp = 3.69 At-rest, Ko = 0.43 Sliding coefficient 2 µ = 0.56 Moist soil unit weight ɣ = 120 pcf Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 12 Description Values Minimum embedment depth below finished grade 3 30 inches Estimated total movement About 1 inch Estimated differential movement About ½ to ¾ of total movement 1. The recommended maximum allowable bearing pressure assumes any unsuitable fill or loose soils, if encountered, will be over-excavated and replaced with properly compacted engineered fill. The design bearing pressure applies to a dead load plus 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 coefficients 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 to reduce differential foundation movement. 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 4.2.8 Grading and Drainage section of this report will nullify the movement estimates provided above. 4.3.4 Spread Footings - Construction Considerations Spread footing construction should only be considered if the estimated foundation movement can be tolerated. Subgrade soils beneath footings should be moisture conditioned and compacted as described in the 4.2 Earthwork section of this report. The moisture content and compaction of subgrade soils should be maintained until foundation construction. Footings and foundation walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. Unstable subgrade conditions should be observed by Terracon to assess the subgrade and provide suitable alternatives for stabilization. Stabilized areas should be proof-rolled prior to continuing construction to assess the stability of the subgrade. Foundation excavations and confirmation of appropriate demolition and reworking below the building pad 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 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 13 4.4 Seismic Considerations Code Used Site Classification 2012 International Building Code (IBC) 1 C 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 35 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 a higher seismic site class for this site is unlikely. 4.5 Floor Systems A slab-on-grade may be utilized for the interior floor system for the proposed building. All existing fill and construction debris associated with demolition of the existing structure should be completely removed and replaced with properly compacted fill prior to construction of the proposed floor slab. If the estimated movement cannot be tolerated, a structurally-supported floor system, supported independent of the subgrade materials, is recommended. Subgrade soils beneath interior and exterior slabs should be scarified to a depth of at least 8 inches, moisture conditioned and compacted. The moisture content and compaction of subgrade soils should be maintained until slab construction. 4.5.1 Floor System - Design Recommendations Even when bearing on properly prepared soils, movement of the slab-on-grade floor system is possible should the subgrade soils undergo an increase in moisture content. We estimate movement of about 1 inch is possible. If the owner cannot accept the risk of slab movement, a structural floor should be used. If conventional slab-on-grade is utilized, the subgrade soils should be prepared as presented in the 4.2 Earthwork section of this report. For structural design of concrete slabs-on-grade subjected to point loadings, a modulus of subgrade reaction of 150 pounds per cubic inch (pci) may be used for floors supported on re- compacted existing soils at the site. Additional floor slab design and construction recommendations are as follows:  Positive separations and/or isolation joints should be provided between slabs and all foundations, columns, or utility lines to allow independent movement. Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 14  Control joints should be saw-cut in slabs in accordance with ACI Design Manual, Section 302.1R-37 8.3.12 (tooled control joints are not recommended) to control the location and extent of cracking.  Interior utility trench backfill placed beneath slabs should be compacted in accordance with the recommendations presented in the 4.2 Earthwork section of this report.  Floor slabs should not be constructed on frozen subgrade.  The use of a vapor retarder should be considered beneath concrete slabs that will be covered with wood, tile, carpet or other moisture sensitive or impervious floor coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer and slab contractor should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder.  Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended. 4.5.2 Floor Systems - Construction Considerations Movements of slabs-on-grade using the recommendations discussed in previous sections of this report will likely be reduced and tend to be more uniform. The estimates discussed above assume that the other recommendations in this report are followed. Additional movement could occur should the subsurface soils become wetted to significant depths, which could result in potential excessive movement causing uneven floor slabs and severe cracking. This could be due to over watering of landscaping, poor drainage, improperly functioning drain systems, and/or broken utility lines. Therefore, it is imperative that the recommendations presented in this report be followed. 4.6 Elevator Pit We anticipate an elevator pit will be included in the interior of the building. The elevator pit will likely consist of reinforced concrete walls with a concrete base slab. Based on our experience with this type of structure, we anticipate the base slabs will be about 5 feet below the level of the finished floor slab. 4.6.1 Elevator Pit Design Recommendations Subsurface conditions in elevator pit excavations are generally anticipated to consist of sands with varying amounts of clay, gravel and possible cobbles. Groundwater was encountered at depths of about 12 to 13 feet below existing site grades at the time of our field exploration. However, groundwater levels can and should be expected to fluctuate over time. We do not anticipate groundwater will significantly impact the elevator pit construction at this site. The elevator pit walls should be designed for the lateral earth pressures imposed by the soil backfill. Earth pressures will primarily be influenced by structural design of the walls, conditions Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 15 of wall restraint and type, compaction and drainage of the backfill. For purposes of design, we have assumed approximately 5 feet of fill will be retained by the pit walls and backfill will consist of the on-site clayey sands. If taller walls are planned, or if different type of backfill is used, we should be contacted to review our data and confirm or modify the design criteria presented below. Active earth pressure is commonly used for design of walls (such as free-standing cantilever retaining walls) and assumes some wall rotation and deflection. For walls that can deflect and rotate about the base, with top lateral movements of about ¼ to ½ percent or more of the wall height, lower “active” earth pressures could be considered for design. Use of the “active” condition assumes deflection and thus cracking of walls could occur. For rigid walls where negligible or very little rotation and deflection will occur, "at-rest" lateral earth pressures should be used in the design. Reinforced concrete pit walls should be designed for lateral earth pressures at least equal to those indicated in the following table. Earth Pressure Conditions Backfill Soil Type Equivalent Fluid Density (pcf) Active (Ka) On-site sands 32 At-Rest (Ko) On-site sands 52 The lateral earth pressures presented above do not include a factor of safety. As such, appropriate factors of safety should be applied to these values. Furthermore, the lateral earth pressures do not include the influence of surcharge, equipment or floor loading, which should be added. 4.6.2 Elevator Pit Construction Considerations The elevator pit excavations should be observed by the geotechnical engineer to confirm that the subsurface conditions are consistent with those encountered in our test borings. If the soil conditions encountered differ from those presented in this report, supplemental recommendations will be required. Where loose or unsuitable bearing materials are encountered in the excavation, these materials should be over-excavated to the minimum depth determined by the geotechnical engineer and replaced with approved engineered fill. Terracon should be contacted to evaluate bearing conditions in the elevator pit excavations well in advance of forming foundations. 4.7 Pavements 4.7.1 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 Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 16 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. 4.7.2 Pavements – Design Recommendations Design of new privately-maintained pavements for the project has been based on the procedures described by the National Asphalt Pavement Associations (NAPA) and the American Concrete Institute (ACI). We assumed the following design parameters for NAPA flexible pavement thickness design:  Automobile Parking Areas  Class I - Parking stalls and parking lots for cars and pick-up trucks, with Equivalent Single Axle Load (ESAL) up to 7,000 over 20 years  Main Traffic Corridors  Class II – Parking lots with a maximum of 10 trucks per day with Equivalent Single Axle Load (ESAL) up to 27,000 over 20 years (Including trash trucks)  Subgrade Soil Characteristics  USCS Classification – SC to SW, classified by NAPA as Medium to Good We assumed the following design parameters for ACI rigid pavement thickness design based upon the average daily truck traffic (ADTT):  Automobile Parking Areas  ACI Category A: Automobile parking with an ADTT of 1 over 20 years  Main Traffic Corridors  ACI Category A: Automobile parking area and service lanes with an ADTT of up to 10 over 20 years  Subgrade Soil Characteristics  USCS Classification – SC to SW  Concrete modulus of rupture value of 600 psi We should be contacted to confirm and/or modify the recommendations contained herein if actual traffic volumes differ from the assumed values shown above. Recommended alternatives for flexible and rigid pavements are summarized for each traffic area as follows: Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 17 Traffic Area Alternative Recommended Pavement Thicknesses (Inches) Asphaltic Concrete Surface Aggregate Base Course1 Portland Cement Concrete Total Automobile Parking Areas (NAPA Class I and ACI Category A) A 3½ 6 -- 9½ B - - 5 5 Main Traffic Corridors (NAPA Class II and ACI Category A) A 4½ 6 - 10½ B - - 6 6 Aggregate base course (if used on the site) 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 aggregate base course. Aggregate 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. Asphaltic 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 (Rice) density (ASTM D2041). Where rigid pavements are used, the concrete should be produced from an approved mix design with the following minimum properties: Properties Value Compressive strength 4,000 psi Cement type Type I or II portland cement Entrained air content (%) 5 to 8 Concrete aggregate ASTM C33 and CDOT section 703 Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from the time the water is added to the mix. 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. Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 18 For areas subject to concentrated and repetitive loading conditions (if any) 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 6 inches underlain by at least 4 inches of granular base. Prior to placement of the granular base, the areas should be thoroughly proofrolled. 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:  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. 4.7.3 Pavements – Construction Considerations 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. 4.7.4 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 Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable 19 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 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 TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY QUADRANGLES INCLUDE: FORT COLLINS, CO (1984). 1901 Sharp Point Dr Ste C SITE LOCATION MAP Fort Collins, CO 80525-4429 221 East Mountain Office Building 221 East Mountain Avenue Fort Collins, CO 20165029 DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES Project Manager: MGH Drawn by: EDB EDB Checked by: EDB Approved by: 4/18/2016 A-1 Project No. Exhibit File Name: Date: Scale: 1”=2,000’ 221 East Mountain Office Building 221 East Mountain Avenue Fort Collins, CO MGH EDB EDB EDB 4/18/2016 20165029 EXPLORATION PLAN AERIAL PHOTOGRAPHY PROVIDED BY MICROSOFT BING MAPS 1901 Sharp Point Dr Ste C Fort Collins, CO 80525-4429 LEGEND DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES Approximate Boring Location Project Manager: Drawn by: Checked by: Approved by: 1 Scale: Project No. File Name: Date: PMT 1 AS SHOWN A-2 Exhibit PMT 2 PMT 1 Approximate Pressuremeter Testing Location Approximate Location of Temporary Benchmark (Top of Manhole Rim – Elevation 4973.5’) MATHEWS STREET EAST MOUNTAIN AVENUE Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ Reliable Exhibit A-3 Field Exploration Description The locations of borings were based upon the proposed development shown on the provided site plan and areas of the site reasonably accessible for a drill rig. The borings were located in the field by measuring from existing site features. The ground surface elevation was surveyed at each boring location referencing the temporary benchmark shown on Exhibit A-2 using an engineer’s level. The borings were drilled with a CME-550X ATV drill rig with solid-stem and hollow-stem augers as well wireline coring. 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 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. Pressuremeter testing was performed at various depths within the sandstone bedrock encountered below the site. Rock coring was also performed in the very hard bedrock layers to provide access for pressuremeter testing. Groundwater measurements were obtained in the borings at the time of site exploration and one day after drilling. After subsequent groundwater measurements were obtained, the borings were backfilled with auger cuttings and sand (if needed) and patched (if needed). Some settlement of the backfill and/or patch may occur and should be repaired as soon as possible. 13 4 16 2 16 18 4974.5 4972.5 4968.5 4961.5 4950.5 4-8-10 N=18 12-12-7 N=19 18-31-25 N=56 50/4" 50/3" 50/3" 0.4 2.0 6.0 13.0 24.3 CONCRETE PAVEMENT - 5 inches CLAYEY SAND, with gravel, dark brown, medium dense WELL GRADED SAND, fine to coarse grained, light brown, medium dense WELL GRADED SAND, with gravels and cobbles, light brown, very dense SEDIMENTARY BEDROCK - SANDSTONE, fine to medium grained, light brown, very hard Boring Terminated at 24.3 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic GRAPHIC LOG THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165029.GPJ TERRACON2015.GDT 4/21/16 221 East Mountain Avenue Fort Collins, Colorado SITE: Page 1 of 1 Advancement Method: Continuous Flight Auger Abandonment Method: Borings backfilled with soil cuttings after delayed groundwater measurement. 1901 Sharp Point Dr Ste C Fort Collins, CO Notes: Project No.: 20165029 Drill Rig: CME-550x Boring Started: 4/4/2016 BORING LOG NO. 1 CLIENT: MAV Development Company South State Commons I Driller: J. Cothron Boring Completed: 4/4/2016 Exhibit: 2723 South State Street, Suite 250 Ann Arbor, MI 48104 8 27 3 2 15 23-14-9 4973.5 4971 4969 4961 4939 0 84 96 100 88 0 76 96 100 88 4-4-6 N=10 5-2-9 N=11 50/5" 50/5" 0.7 3.0 5.0 13.0 35.0 PAVEMENT SECTION - Asphalt pavement (3 inches) over Concrete (4 inches) CLAYEY SAND WITH GRAVEL (SC), brown, medium dense WELL GRADED SAND WITH GRAVEL, light brown, medium dense WELL GRADED SAND WITH GRAVEL, with cobbles and gravels, light brown, medium dense to very dense SEDIMENTARY BEDROCK - SANDSTONE, gray to dark gray, very hard Boring Terminated at 35 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic GRAPHIC LOG THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165029.GPJ TERRACON2015.GDT 4/21/16 221 East Mountain Avenue Fort Collins, Colorado SITE: Page 1 of 1 Advancement Method: Hollow-stem auger (0-14.4); NQ Wireline core (14.4-35) Abandonment Method: Borings backfilled with soil cuttings and patched upon completion. 1901 Sharp Point Dr Ste C Fort Collins, CO Notes: Project No.: 20165029 Drill Rig: CME-550x Boring Started: 4/4/2016 BORING LOG NO. 2 38 2 13 3 3 12 23-15-8 4974.5 4974 4972 4962 4944 70 100 84 100 70 96 72 70 3-3-2 N=5 7-11-35 N=46 37-45-43 N=88 50/5" 0.5 1.0 3.0 13.0 31.0 CONCRETE PAVEMENT - 6 inches BASE COARSE- Sand and Gravel CLAYEY SAND (SC), dark brown, loose WELL GRADED SAND WITH GRAVEL, with clay and some gravel and cobbles, very dense SEDIMENTARY BEDROCK - SANDSTONE, gray, very hard Boring Terminated at 31 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic GRAPHIC LOG THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165029.GPJ TERRACON2015.GDT 4/21/16 221 East Mountain Avenue Fort Collins, Colorado SITE: Page 1 of 1 Advancement Method: Hollow-stem auger (0-14.4); NQ Wireline core (14.4-31) Abandonment Method: Borings backfilled with soil cuttings and patched upon completion. 1901 Sharp Point Dr Ste C Fort Collins, CO Notes: Project No.: 20165029 Drill Rig: CME-550x Boring Started: 4/5/2016 BORING LOG NO. 3 CLIENT: MAV Development Company South State Commons I 49 15 3 5 2 7 28-22-6 4974 4970.5 4960.5 4959.5 4959 2-4-10 N=14 12-23-18 N=41 28-34-14 N=48 20/4" 50/3" 50/3" 0.5 4.0 14.0 15.0 15.3 PAVEMENT SECTION - Asphalt pavement (2.4 inches) over Concrete (3 inches) CLAYEY SAND, dark brown, medium dense to dense SILTY CLAYEY SAND (SC-SM), with gravel and cobbles, light gray to red-brown, very dense WEATHERED BEDROCK - SANDSTONE, fine grained, olive to gray, weathered SEDIMENTARY BEDROCK - SANDSTONE, light brown to gray, very hard Boring Terminated at 15.3 Feet Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic GRAPHIC LOG THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165029.GPJ TERRACON2015.GDT 4/21/16 221 East Mountain Avenue Fort Collins, Colorado SITE: Page 1 of 1 Advancement Method: Hollow-stem auger Abandonment Method: Borings backfilled with soil cuttings and patched upon completion. 1901 Sharp Point Dr Ste C Fort Collins, CO Notes: Project No.: 20165029 Drill Rig: CME-550x Boring Started: 4/4/2016 BORING LOG NO. 4 CLIENT: MAV Development Company South State Commons I Driller: J. Cothron Boring Completed: 4/4/2016 Exhibit: No 24.00 ft 3.28 ft 0.33 Probe size: 1.000 Pressure Volume Pressure Volume DR/R0 psi in³ psi in³ % 0 0.0 12 0.0 0.00 51,038 psi 73 44.1 80 43.7 18.53 145 46.2 152 45.5 19.23 ◄ 1,166 psi 218 47.2 225 46.2 19.50 290 48.0 297 46.7 19.68 ◄ 43.78 363 48.7 370 47.0 19.81 435 49.8 442 47.8 20.10 297 psi #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 3.92 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A Raw Readings Project name: Borehole name: Test number: Test date: (mm/dd/yyyy) TEXAM Pressuremeter Test Test depth: Manometer height above ground: 221 East Mountain Office Building B-2 4/4/2016 Use of a slotted casing: PRESSIO COMPANION V.15 Ratio E / PL : Yield pressure PF : Ratio PL / PF : Pressuremeter probe was unable to maintain pressure after reaching a maximum pressure of 30 bar. Calibration Sheet Reference 2 Remarks Ultimate pressure PL : 2 No 33.00 ft 3.28 ft 0.33 Probe size: 1.000 Pressure Volume Pressure Volume DR/R0 psi in³ psi in³ % 0 0.0 16 0.0 0.00 51,676 psi 73 19.2 85 18.8 8.37 145 20.7 158 20.1 8.90 ◄ 1,680 psi 218 21.7 230 20.7 9.15 290 22.5 302 21.2 9.37 30.75 363 23.2 375 21.5 9.51 ◄ 435 24.2 447 22.2 9.78 375 psi 508 25.6 520 23.3 10.26 580 27.5 592 24.9 10.91 4.48 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A Ultimate pressure PL : 1 N Fluid density: Corrected Readings Poisson's coefficient: Pressiometric modulus E: Test Results PRESSIO COMPANION V.15 Ratio E / PL : Yield pressure PF : Ratio PL / PF : Pressuremeter probe was unable to maintain pressure after reaching a maximum pressure of 40 bar. Calibration Sheet Reference 2 Remarks TEXAM Pressuremeter Test Test depth: Manometer height above ground: 221 East Mountain Office Building B-2 4/4/2016 Use of a slotted casing: No 28.50 ft 3.28 ft 0.33 Probe size: 1.000 Pressure Volume Pressure Volume DR/R0 psi in³ psi in³ % 0 0.0 14 0.0 0.00 121,495 psi 73 29.5 83 29.1 12.67 145 30.9 155 30.0 13.05 ◄ 2,028 psi 218 31.9 227 30.6 13.27 290 32.6 300 30.9 13.43 59.90 363 33.3 372 31.1 13.50 435 33.9 445 31.3 13.58 662 psi 508 34.4 517 31.4 13.60 580 34.9 590 31.5 13.65 3.06 653 35.4 662 31.6 13.68 ◄ 725 35.8 735 31.6 13.68 798 36.7 807 32.0 13.85 870 37.3 880 32.2 13.93 943 38.1 952 32.6 14.08 1015 39.1 1025 33.1 14.30 1088 40.3 1097 33.9 14.62 1160 41.8 1170 35.0 15.07 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A Ultimate pressure PL : 3 N Fluid density: Corrected Readings Poisson's coefficient: Pressiometric modulus E: Test Results PRESSIO COMPANION V.15 Ratio E / PL : Yield pressure PF : Ratio PL / PF : Calibration Sheet Reference 3 Remarks TEXAM Pressuremeter Test Test depth: Manometer height above ground: 221 East Mountain Office Building B-3 4/5/2016 Use of a slotted casing: Raw Readings Project name: APPENDIX B LABORATORY TESTING Geotechnical Engineering Report 221 East Mountain Office Building ■ Fort Collins, Colorado April 20, 2016 ■ Terracon Project No. 20165029 Responsive ■ Resourceful ■ 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. Procedural standards noted in this report are for reference to methodology in general. In some cases variations to methods are applied as a result of local practice or professional judgment.  Water content  Plasticity index  Grain-size distribution  Water-soluble sulfate content  Dry density 0 10 20 30 40 50 60 0 20 40 60 80 100 CL or OL CH or OH ML or OL MH or OH Boring ID Depth PL PI Description CLAYEY SAND with GRAVEL CLAYEY SAND SILTY, CLAYEY SAND SC SC SC-SM Fines P L A S T I C I T Y I N D E X LIQUID LIMIT "U" Line "A" Line 23 23 28 14 15 22 9 8 6 27 38 49 LL USCS 2 3 4 ATTERBERG LIMITS RESULTS ASTM D4318 2 - 3.5 2 - 3.5 14 - 14.3 PROJECT NUMBER: 20165029 PROJECT: 221 East Mountain Office Building 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 100 10 1 0.1 0.01 0.001 1 2 3 3 4 23 23 28 0.354 0.091 0.599 2.168 1.187 0.221 2.991 0.104 25 25 19 25 19 6 16 20 30 40 50 1.5 6 200 810 26.9 29.0 10.1 30.7 8.7 0.162 14 13.0 26.9 38.0 1.5 49.2 TASK NO: 160411020 Analytical Results Terracon, Inc. - Fort Collins Eric D. Bernhardt Company: Report To: Company: Bill To: 1901 Sharp Point Drive Suite C Fort Collins CO 80525 Accounts Payable Terracon, Inc. - Lenexa 13910 W. 96th Terrace Lenexa KS 66215 20165029 Date Reported: 4/18/16 Task No.: 160411020 Matrix: Soil - Geotech Date Received: 4/11/16 Client Project: Client PO: Customer Sample ID 20165029 B1 @ 2 Ft. Test Method Lab Number: 160411020-01 Result Sulfate - Water Soluble 0.007 % AASHTO T290-91/ ASTM D4327 240 South Main Street / Brighton, CO 80601-0507 / 303-659-2313 Mailing Address: P.O. Box 507 / Brighton, CO 80601-0507 / Fax: 303-659-2315 DATA APPROVED FOR RELEASE BY Abbreviations/ References: 160411020 AASHTO - American Association of State Highway and Transportation Officials. ASTM - American Society for Testing and Materials. ASA - American Society of Agronomy. DIPRA - Ductile Iron Pipe Research Association Handbook of Ductile Iron Pipe. APPENDIX C SUPPORTING DOCUMENTS Exhibit: C-1 Unconfined Compressive Strength Qu, (psf) 500 to 1,000 2,000 to 4,000 4,000 to 8,000 1,000 to 2,000 less than 500 > 8,000 Non-plastic Low Medium High DESCRIPTION OF SYMBOLS AND ABBREVIATIONS SAMPLING WATER LEVEL FIELD TESTS 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 Trace With Modifier RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Trace With Modifier DESCRIPTIVE SOIL CLASSIFICATION Boulders Cobbles Gravel Sand 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 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. Design Soluble Sulfate Used to determine the quantitative amount of soluble sulfates within a soil mass. Corrosion Potential 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. Silt or Clay Descriptive Term(s) of other constituents N (HP) (T) (DCP) (PID) (OVA) < 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 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. Standard Penetration Test Resistance (Blows/Ft.) Hand Penetrometer Torvane Dynamic Cone Penetrometer Photo-Ionization Detector Organic Vapor Analyzer STRENGTH TERMS Standard Penetration or N-Value Blows/Ft. Descriptive Term (Consistency) Descriptive Term (Density) CONSISTENCY OF FINE-GRAINED SOILS (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. (More than 50% retained on No. 200 sieve.) Density determined by Standard Penetration Resistance RELATIVE DENSITY OF COARSE-GRAINED SOILS Hard > 30 > 50 Very Stiff 15 - 30 Stiff Medium Stiff Very Soft 0 - 1 Medium Dense Loose Soft Very Dense Dense 30 - 50 8 - 15 10 - 29 4 - 8 4 - 9 2 - 4 Very Loose 0 - 3 %Fines LL PL PI 1 4 3/4 1/2 60 fine 1 2 3 3 4 18.42 GRAIN SIZE IN MILLIMETERS PERCENT FINER BY WEIGHT coarse fine U.HYDROMETERS. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 14 15 22 9 8 6 0.74 D100 Cc Cu SILT OR CLAY 4 D30 D10 %Gravel %Sand 9 - 10.5 2 - 3.5 2 - 3.5 9 - 10.5 14 - 14.3 3/8 3 100 3 2 140 COBBLES GRAVEL SAND USCS Classification 60.1 44.1 51.8 67.8 42.1 D60 coarse medium Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION 9 - 10.5 2 - 3.5 2 - 3.5 9 - 10.5 14 - 14.3 () CLAYEY SAND with GRAVEL (SC) CLAYEY SAND (SC) POORLY GRADED SAND with GRAVEL (SP) SILTY, CLAYEY SAND (SC-SM) ASTM D422 / ASTM C136 PROJECT NUMBER: 20165029 PROJECT: 221 East Mountain Office Building SITE: 221 East Mountain Avenue Fort Collins, Colorado CLIENT: MAV Development Company South State Commons I EXHIBIT: B-3 1901 Sharp Point Dr Ste C Fort Collins, CO LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 20165029.GPJ 35159097 - ATTERBERG ISSUE.GPJ 4/18/16 SITE: 221 East Mountain Avenue Fort Collins, Colorado CLIENT: MAV Development Company South State Commons I EXHIBIT: B-2 1901 Sharp Point Dr Ste C Fort Collins, CO LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. ATTERBERG LIMITS 20165029.GPJ TERRACON2015.GDT 4/18/16 CL-ML Borehole name: Test number: Test date: (mm/dd/yyyy) 0 20 40 60 80 100 120 140 160 180 0 500 1000 1500 2000 2500 Volume (in³) Pressure (psi) Pressuremeter Test - Corrected Curve Raw Readings Project name: Borehole name: Test number: Test date: (mm/dd/yyyy) 0 20 40 60 80 100 120 140 160 0 200 400 600 800 1000 1200 1400 1600 1800 Volume (in³) Pressure (psi) Pressuremeter Test - Corrected Curve N Fluid density: Corrected Readings Poisson's coefficient: Pressiometric modulus E: Test Results 0 50 100 150 200 250 0 200 400 600 800 1000 1200 1400 Volume (in³) Pressure (psi) Pressuremeter Test - Corrected Curve 2723 South State Street, Suite 250 Ann Arbor, MI 48104 A-7 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. PROJECT: 221 East Mountain Office Building PERCENT FINES WATER CONTENT (%) ATTERBERG LIMITS LL-PL-PI Surface Elev.: 4974.3 (Ft.) ELEVATION (Ft.) SAMPLE TYPE WATER LEVEL OBSERVATIONS DEPTH (Ft.) 5 10 15 RECOVERY (%) RQD (%) FIELD TEST RESULTS DEPTH LOCATION See Exhibit A-2 Latitude: 40.58654401° Longitude: -105.074265° Boring collapsed upon removal of augers 12' while drilling Boring collapsed upon removal of augers WATER LEVEL OBSERVATIONS 12' while drilling Driller: J. Cothron Boring Completed: 4/5/2016 Exhibit: 2723 South State Street, Suite 250 Ann Arbor, MI 48104 A-6 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. PROJECT: 221 East Mountain Office Building PERCENT FINES WATER CONTENT (%) ATTERBERG LIMITS LL-PL-PI Surface Elev.: 4975.1 (Ft.) ELEVATION (Ft.) SAMPLE TYPE WATER LEVEL OBSERVATIONS DEPTH (Ft.) 5 10 15 20 25 30 RECOVERY (%) RQD (%) FIELD TEST RESULTS DEPTH LOCATION See Exhibit A-2 Latitude: 40.58655096° Longitude: -105.074586° No free water observed WATER LEVEL OBSERVATIONS CLIENT: MAV Development Company South State Commons I Driller: J. Cothron Boring Completed: 4/4/2016 Exhibit: 2723 South State Street, Suite 250 Ann Arbor, MI 48104 A-5 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. PROJECT: 221 East Mountain Office Building PERCENT FINES WATER CONTENT (%) ATTERBERG LIMITS LL-PL-PI Surface Elev.: 4974.1 (Ft.) ELEVATION (Ft.) SAMPLE TYPE WATER LEVEL OBSERVATIONS DEPTH (Ft.) 5 10 15 20 25 30 35 RECOVERY (%) RQD (%) FIELD TEST RESULTS DEPTH LOCATION See Exhibit A-2 Latitude: 40.58679001° Longitude: -105.074287° No free water observed WATER LEVEL OBSERVATIONS A-4 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. PROJECT: 221 East Mountain Office Building PERCENT FINES WATER CONTENT (%) ATTERBERG LIMITS LL-PL-PI Surface Elev.: 4974.7 (Ft.) ELEVATION (Ft.) SAMPLE TYPE WATER LEVEL OBSERVATIONS DEPTH (Ft.) 5 10 15 20 RECOVERY (%) RQD (%) FIELD TEST RESULTS DEPTH LOCATION See Exhibit A-2 Latitude: 40.586816° Longitude: -105.07463° 13' while drilling 12.6' on 4/5/2016 WATER LEVEL OBSERVATIONS