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HomeMy WebLinkAboutWARREN FEDERAL CREDIT UNION - PDP - PDP150011 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT WARREN FEDERAL CREDIT UNION – EAST LOT DEVELOPMENT RIGDEN FARM 16TH FILING FORT COLLINS, COLORADO EEC PROJECT NO. 1152043 Prepared for: RB+B Architects, Inc. c/o Warren Federal Credit Union 315 East Mountain Avenue, Suite 100 Fort Collins, Colorado 80524 Attn: Mr. David Kress, Principal (dkress@rbbarchitects.com) Prepared by: Earth Engineering Consultants, LLC 4396 Greenfield Drive Windsor, Colorado 80550 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 June 16, 2015 RB+B Architects, Inc. c/o Warren Federal Credit Union 315 East Mountain Avenue, Suite 100 Fort Collins, Colorado 80524 Attn: Mr. David Kress, Principal (dkress@rbbarchitects.com) Re: Subsurface Exploration Report Warren Federal Credit Union – East Lot Development Rigden Farm 16th Filing Fort Collins, Colorado EEC Project No. 1152043 Mr. Kress: Enclosed, herewith, are the results of the geotechnical subsurface exploration for the proposed Warren Federal Credit Union – East Lot Development planned for construction on Rigden Farm 16th Filing in Fort Collins, Colorado. The proposed project site is located north of Limon Drive and east of Iowa Drive near Drake and Timberline in Fort Collins. This exploration was completed in general accordance with our proposal dated April 28, 2015. In summary, the near surface subsurface materials encountered within the soil borings completed for this project consisted of lean clays varying amounts of sand, which extended to depths on the order of 16 to 17 feet. The in-situ cohesive subsoils revealed low swell potential characteristics with some consolidation potential. The subgrade soils were variable in moisture content and consistency. Boring B-1 revealed lightweight characteristics of the clay subsoils. Sand and gravel granular subsoils were encountered in Borings B-2 and B-3 and extended to the depths explored and/or to the underlying bedrock formation. Claystone/siltstone bedrock was encountered in boring B-2 at an approximate depth of 24½ feet below existing site grades and extended to the depths explored, approximately 25½ feet. Groundwater was encountered in the deeper foundation related borings at approximate depths of 16 to 17 feet below existing grade. In review of the field and laboratory test results, we observed the upper portion of the cohesive subsoils were stiff to very stiff in consistency, exhibited variable in-situ moisture contents and GEOTECHNICAL SUBSURFACE EXPLORATION REPORT WARREN FEDERAL CREDIT UNION – EAST LOT DEVELOPMENT RIGDEN FARM 16TH FILING FORT COLLINS, COLORADO EEC PROJECT NO. 1152043 June 16, 2015 INTRODUCTION The subsurface exploration for the Warren Federal Credit Union (WFCU) – East Lot Development on the Rigden Farm 16th Filing parcel south of Drake Road and east of Timberline Road in Fort Collins, Colorado, has been completed. For this exploration a total of six (6) soil borings were completed within the development area to obtain information on existing subsurface conditions. The borings were extended to depths of approximately 10 feet below present site grades in proposed pavement areas and 15 to 25 feet in proposed building areas. Individual boring logs and a site diagram indicating the approximate boring locations are provided with this report. We understand this project includes the construction of a new two-story, steel frame building to house WFCU and three additional retail spaces with associated drive and parking areas to the north of the building. The new building will have a total plan area of approximately 11,000 sf with WFCU occupying approximately 3,000 sf including an approximate 1,000 sf lobby area. The new building is expected to have relatively light foundation loads with maximum wall and column loads on the order of 4 klf and 150 kips, respectively. Floor loads are expected to be light. Associated drive and parking traffic is expected to include predominately automobiles in most areas and moderate truck traffic in limited areas. An ATM drive up for WFCU will be located in the pavement area. Minor grade changes are expected to develop final site grades for the new building and parking. The purpose of this report is to describe the subsurface conditions encountered in the completed exploration borings, analyze and evaluate the test data, and provide geotechnical recommendations concerning design and construction of the foundations and support of floor slabs and pavements. EXPLORATION AND TESTING PROCEDURES The boring locations were established in the field by a representative of Earth Engineering Consultants, LLC (EEC) by pacing and estimating angles from identifiable site features. The locations of the borings should be considered accurate only to the degree implied by the methods Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 2 used to make the field measurements. Photographs of the site taken at the time of drilling are provided with this report. The borings were performed using a truck mounted, CME-55 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers. Samples of the subsurface materials encountered were obtained using split-barrel and California barrel sampling techniques in general accordance with ASTM Specifications D1586 and D3550, respectively. In the split-barrel and California barrel sampling procedures, standard sampling spoons are driven into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the samplers is recorded and is used to estimate the in-situ relative density of cohesionless materials and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. Relatively intact samples are obtained with the California sampler. All samples obtained in the field were sealed and returned to our laboratory for further examination, classification, and testing. Laboratory moisture content tests were performed on each of the recovered samples. In addition, the unconfined strength of appropriate samples was estimated using a calibrated hand penetrometer. Washed sieve analysis and Atterberg limits tests were completed on selected samples to evaluate the quantity and plasticity of the fines in the subgrade soils. Swell/consolidation tests were completed on selected samples to evaluate the tendency of the soil to change volume with variation in moisture content and load. Selected samples of near surface soils were also tested to determine quantities of water soluble sulfates to evaluate the potential for sulfate attack on site concrete. Results of the outlined tests are indicated on the attached boring logs and summary sheets. As a part of the testing program, all samples were examined in the laboratory and classified in general accordance with the attached General Notes and the Unified Soil Classification System based on the texture and plasticity of the soil. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs. A brief description of the Unified Soil Classification System is included with this report. Classification of the bedrock was based on visual Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 3 and tactual observation of disturbed samples and auger cuttings. Coring and/or petrographic analysis may reveal other rock types. SITE AND SUBSURFACE CONDITIONS The proposed WFCU project site is located between Drake Road and Limon Drive on the north and south and is between Iowa and Illinois Drives on the east and west. This report addresses the development of the east portion of that lot. The development parcel is currently a vacant tract of land with sparse vegetation and is relatively flat, exhibiting slight surface drainage in the east and north with less than 5 feet of relief across the site. Evidence of prior building construction was not observed on the referenced property by EEC field personnel. An EEC field engineer was on site during the drilling operations to evaluate the subsurface conditions encountered and supervise the drilling activities. Field logs prepared by EEC site personnel were based on visual and tactual observation of disturbed samples and auger cuttings. The final boring logs included with this report may contain modifications to the field logs based on the results of laboratory testing and evaluation. Based on the results of the field borings and laboratory evaluation, subsurface conditions can be generalized as follows. Sparse vegetation was observed at the ground surface across the site. Materials classified as lean clay with variable amounts of sand were encountered beneath the vegetation layer. A portion of the near surface subgrade soils may be materials reworked during prior site grading. The near surface subgrades were generally stiff to very stiff with a very stiff red-brown layer encountered between depths of approximately 6 and 11 feet. Cohesive soils extended to depths of approximately 16 to 17 feet in borings B-2 and B-3 and were underlain by sands and gravels. Claystone/siltstone/sandstone bedrock was encountered at a depth of approximately 24 feet in boring B-2. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil and rock types. In-situ, the transition of materials may be gradual and indistinct. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 4 GROUNDWATER CONDITIONS Observations were made while drilling and after completion of the borings to detect the presence and depth to hydrostatic groundwater. At the time of drilling, free water was observed in the deeper foundation related borings at depths of approximately 16 to 17 feet below existing site grades. Groundwater was not encountered in the shallower building or pavement/parking related borings. The borings were backfilled upon completion of the drilling operations; therefore subsequent measurements were not obtained. Fluctuations in groundwater levels can occur over time depending on variations in hydrologic conditions and other conditions not apparent at the time of this report. Longer term monitoring of water levels in cased wells, sealed from the influence of surface water, would be required to more accurately evaluate fluctuations in groundwater levels at the site. We have typically noted deepest groundwater levels in late winter and shallowest groundwater levels in mid to late summer. Zones of perched and/or trapped water can be encountered at times throughout the year in more permeable zones in the subgrade soils and perched water is commonly observed in subgrade soils immediately above lower permeability bedrock. Perched water is also likely to be observed in the subgrades immediately above the denser/harder red-brown sandy lean clay state. ANALYSIS AND RECOMMENDATIONS Swell – Consolidation Test Results The swell-consolidation test is performed to evaluate the swell or consolidation potential of soils or bedrock to assist in determining foundation, floor slab and pavement design criteria. In this test, relatively intact samples obtained directly from the California barrel sampler are placed in a laboratory apparatus and inundated with water under a predetermined load. The swell-index is the resulting amount of swell or collapse after the inundation period expressed as a percent of the sample’s initial thickness. The inundated samples are samples are monitored for swell and consolidation with additional incremental loads applied after the initial inundation period to evaluate the swell pressure and consolidation characteristics. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 5 For this assessment, we conducted seven (7) swell-consolidation tests on subgrade soil samples. The swell index values for the in-situ soil samples analyzed revealed low to moderate swell characteristics as indicated on the attached swell test summaries. The (+) test results indicate the material’s swell potential characteristics while the (-) test results indicate the material’s collapse/consolidation potential characteristics when inundated with water. The following tables summarize the swell-consolidation laboratory test results for samples obtained during our field explorations for the subject site. TABLE I - Swell Consolidation Test Results Boring No. Depth, ft. Material Type In-Situ Moisture Content, % Dry Density, PCF Inundation Pressure, psf Swell Index, (+/-) % B-1 4' Lean Clay with Sand 9.8 86.8 500 (+) 0.1% B-2 2' Lean Clay with Sand 15.8 98.4 150 (+) 2.4% B-2 9' Lean Clay with Sand 13.7 115.2 500 (+) 2.5% B-3 4' Lean Clay with Sand 8.7 101.0 500 (+) 0.4% B-4 2' Lean Clay with Sand 15.6 108.8 150 (+) 1.1% B-5 2' Lean Clay with Sand 18.4 106.6 150 (+) 0.4% B-6 2' Lean Clay with Sand 15.1 114.7 150 (+) 0.8% Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide uniformity in terminology between geotechnical engineers to provide a relative correlation of slab performance risk to measured swell. “The representative percent swell values are not necessarily measured values; rather, they are a judgment of the swell of the soil and/or bedrock profile likely to influence slab performance.” Geotechnical engineers use this information to also evaluate the swell potential risks for foundation performance based on the risk categories. Table II - Recommended Representative Swell Potential Descriptions and Corresponding Slab Performance Risk Categories Slab Performance Risk Category Representative Percent Swell (500 psf Surcharge) Representative Percent Swell (1000 psf Surcharge) Low 0 to < 3 0 < 2 Moderate 3 to < 5 2 to < 4 High 5 to < 8 4 to < 6 Very High > 8 > 6 Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 6 Based on the laboratory test results, the in-situ samples analyzed for this project were within the low to moderate range. However, the near surface subgrade soils exhibit a potential to consolidate when wetted and under load. General Considerations and Site Preparation As presented on the enclosed boring logs and laboratory test results, low density, consolidation prone cohesive soils are present on this site. This report provides recommendations to help mitigate the effects of soil consolidation. Even if these procedures are followed, some movement and at least minor cracking in the site structures should be anticipated. The severity of cracking and other cosmetic damage such as uneven floor slabs will probably increase if any modification of the site results in excessive wetting or drying of the site’s subsoils. Eliminating the risk of movement and cosmetic distress may not be feasible, but it may be possible to further reduce the risk of movement if significantly more extensive/expensive measures are used during construction. To reduce the potential movement of foundations and floor slabs included herein are recommendations for a limited over-excavation and replacement concept. This approach will significantly reduce but not eliminate post construction movement. All existing topsoil/vegetation and apparent fill materials should be removed from the site improvement areas. To reduce the potential for post-construction movement caused by consolidation of the dry, in-situ soils, we recommend the entire building footprints be over- excavated and replaced as moisture conditioned/compacted engineered controlled fill. The over- excavation should extent to a depth to allow for at least 2 feet of processed/engineered controlled fill material below all foundation bearing elements. Since movement of pavements is generally more tolerable, in our opinion, the over-excavation in the pavement areas could be omitted. The over- excavated areas should extend laterally in all directions beyond the edges of the foundations a minimum 8 inches for every 12 inches of over-excavated depth below the foundations. After removal of all topsoil/vegetation within the planned development areas, as well as removal of unacceptable or unsuitable subsoils, removal of over-excavation materials, and removal of any previous fill material, and prior to placement of fill and/or site improvements, the exposed soils Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 7 should be scarified to a minimum depth of 9 inches, adjusted in moisture content to within (+/-) 2% of standard Proctor optimum moisture content and compacted to at least 95% of the material's standard Proctor maximum dry density as determined in accordance with ASTM Specification D698. Fill materials used to replace the over-excavated zone and establish grades in the building areas, after the initial zone has been prepared as recommended above, should consist of approved on-site lean clay with sand subsoils or approved structural fill material which is free from organic matter and debris. If on-site cohesive subsoils are used as engineered fill, they should be placed in maximum 9-inch thick loose lifts, and be moisture conditioned and compacted as recommended for the scarified soils. If structural fill materials are used they should be graded similarly to a CDOT Class 5, 6 or 7 aggregate base with sufficient fines to prevent ponding of water within the fill. Structural fill material should be placed in loose lifts not to exceed 9 inches thick, adjusted to a workable moisture content and compacted to at least 95% of standard Proctor maximum dry density as determined by ASTM Specification D698. Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade materials. The site lean clay with sand soils will be subject to instability/pumping with elevated moisture contents. Positive drainage should be developed away from the structures and pavements to avoid wetting of subgrade materials. Subgrade materials becoming wet subsequent to construction of the site improvements can result in unacceptable performance. Foundation Systems – General Considerations The site appears suitable for the proposed construction based on the results of our field exploration and review of the proposed development plans. The following foundation system was evaluated for use on the site with the understanding of slab-on-grade structures.  Conventional type spread footings bearing on over-excavated and replaced with approved on-site reconditioned/engineered fill material or an approved imported fill material are suitable for use. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 8 The bearing capacity value provided herein is for the use of on-site reconditioned engineered fill material placed and compacted as described herein. Particular attention will be required during the supplemental site observations, such as “open-hole” or foundation excavation observations to further assess the soil conditions and foundation design bearing strata for the building. Footing Foundations The upper level cohesive soils exhibited consolidation characteristics and low to moderate bearing characteristics. To reduce the potential for excessive post-construction settlement/movement of the footings, we recommend the in-place soils be removed/over-excavated to allow for at least 2 feet of processed/engineered controlled fill material below all foundation bearing elements. The over- excavated zone could be backfilled with on-site reconditioned engineered fill or approved imported structural fill material placed and compacted as described in the “General Considerations and Site Preparation” section of this report. Prior to placement and compaction of the engineered fill material and/or approved structural fill an open-hole/foundation excavation observation should be performed to observe the existing subsoils below the fill zone to determine if additional over-excavation is necessary. Footings bearing on a zone of at least 2 feet of approved engineered fill and/or structural fill material placed and compacted as described in the “General Considerations and Site Preparation” section of this report could be designed for a maximum net allowable total load soil bearing pressure of 1,500 psf. A minimum dead load pressure would not be required. The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load includes full dead load and live load conditions. Footings should be placed on similar subsoils to reduce the potential for differential movement of dissimilar material, and should also be proportioned to reduce differential foundation movement. We estimate the total long term settlement of footings designed as outlined above would be about 1- inch. If actual design loads exceed the assumed values as previously presented and/or if the Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 9 anticipated movement cannot be tolerated, consideration could be given to use of a deep foundation system such as a grade beam and straight shaft drilled pier foundation system. Other deep foundation systems could also be considered and additional recommendations could be developed for deep foundations; however, would involve additional field exploration. After placement of the fill materials for foundation support, care should be taken to avoid wetting or drying of those materials. Bearing materials, which are loosened or disturbed by the construction activities or materials, which become dry and desiccated or wet and softened, should be removed and replaced or reworked in place prior to construction of the overlying improvements. The silty subgrade soils will be subject to instability at elevated moisture contents. Exterior foundations and foundations in unheated areas should be located at least 30 inches below adjacent exterior grade to provide frost protection. We recommend formed continuous footings have a minimum width of 16 inches and isolated column foundations have a minimum width of 30 inches. Seismic Conditions The site soil conditions consist of approximately 25 feet of overburden soils overlying soft to moderately hard bedrock. For those site conditions, the 2012 International Building Code indicates a Seismic Site Classification of D. Lateral Earth Pressures For any portion of the site improvements constructed below grade, those portions will be subject to lateral earth pressures. Passive lateral earth pressures may help resist the driving forces for retaining wall or other similar site structures. Active lateral earth pressures could be used for design of structures where some movement of the structure is anticipated, such as retaining walls. The total deflection of structures for design with active earth pressure is estimated to be on the order of one half of one percent of the height of the down slope side of the structure. We recommend at-rest pressures be used for design of structures where rotation of the walls is restrained. Passive pressures and friction between the footing and bearing soils could be used for design of resistance to movement of retaining walls. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 10 Coefficient values for backfill with anticipated types of soils for calculation of active, at rest and passive earth pressures are provided in the table below. Equivalent fluid pressure is equal to the coefficient times the appropriate soil unit weight. Those coefficient values are based on horizontal backfill with backfill soils consisting of essentially granular materials with a friction angle of 35 degrees or low volume change cohesive soils. For the at-rest and active earth pressures, slopes down and away from the structure would result in reduced driving forces with slopes up and away from the structures resulting in greater forces on the walls. The passive resistance would be reduced with slopes away from the wall. The top 30-inches of soil on the passive resistance side of walls could be used as a surcharge load; however, should not be used as a part of the passive resistance value. Frictional resistance is equal to the tangent of the friction angle times the normal force. Table III – Lateral Earth Pressure Coefficients Soil Type On-Site Cohesive Soils Import Structural Fill Wet Unit Weight 115 135 Saturated Unit Weight 135 140 Friction Angle () – (assumed) 25° 35° Active Pressure Coefficient 0.40 0.27 At-rest Pressure Coefficient 0.58 0.43 Passive Pressure Coefficient 2.46 3.70 Surcharge loads or point loads placed in the backfill can also create additional loads on below grade walls. Those situations should be designed on an individual basis. The outlined values do not include factors of safety nor allowances for hydrostatic loads and are based on assumed friction angles, which should be verified after potential material sources have been identified. Care should be taken to develop appropriate drainage systems behind below grade walls to eliminate potential for hydrostatic loads developing on the walls. Those systems would likely include perimeter drain systems extending to sump areas or free outfall where reverse flow cannot occur in the system. Where necessary, appropriate hydrostatic load values should be used for design. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 11 Floor Slabs In our opinion, floor slabs could be supported on a zone of engineered fill material and/or approved structural fill material following the protocol outlined in the section titled “General Conditions and Site Preparation” to allow for at least 2 feet of processed/engineered controlled fill material beneath all interior floor slabs. With fill extending at least 2 feet below foundation bearing, the fill below the floors will likely be greater than 2 feet. Floor slabs supported on reconditioned engineered fill could be designed using a modulus of subgrade support (k-value) of 100 pci. We estimate the long term movement of slab-on-grade floors with properly prepared subgrade subsoils as outlined above would be on the order of 1-inch. Care should be taken after preparation of the subgrades to avoid disturbing the subgrade materials. Materials which are loosened or materials which become dry and desiccated or wet and softened should be removed and replaced prior to placement of the overlying floor slabs. Care should be taken to maintain proper moisture contents in the subgrade soils prior to placement of any overlying improvements. An underslab gravel layer or thin leveling course could be used underneath the concrete floor slabs to provide a capillary break mechanism, a load distribution layer, and as a leveling course for the concrete placement. 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.  Control joints should be provided in slabs to control the location and extent of cracking.  Interior trench backfill placed beneath slabs should be compacted in a similar manner as previously described for footing and floor slab fill. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 12  In areas subjected to normal loading, a 4 to 6-inch layer of clean-graded gravel or aggregate base course should be placed beneath interior floor slabs.  Floor slabs should not be constructed on frozen subgrade.  Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended. Pavement Subgrades/Pavement Design Sections Subgrades for site pavements should be prepared as outlined in the section titled "General Considerations and Site Preparation." It will be necessary to maintain the moisture content of the prepared subgrade up to and immediately prior to surfacing. Densification of subgrade soils can occur with construction traffic. Prior to surfacing the roadway subgrades with aggregate base, we recommend the subgrades be proof rolled to help identify any soft or yielding areas. Soft or yielding areas delineated by the proof rolling operations should be undercut or stabilized in-place to achieve the appropriate subgrade support. The site’s cohesive subsoils would likely be unstable and show pumping with higher moisture contents. If unstable subgrades exist due to pumping conditions after subgrade preparation stage, consideration should be given to stabilizing top 12 inches of pavement subgrades with the use of an ASTM C618 Class C fly ash. We estimate stabilization of the site lean clay with sand / sandy lean clay soils could be accomplished by incorporating at least 12%, by dry weight of Class C fly ash into the upper 12 inches of subgrade. To take full advantage of the increased stiffness of a stabilized subgrade for a reduction in pavement thickness, a mix design utilizing the fly ash with the site soils would be required prior to surfacing. We expect the site pavements will include areas designated primarily for automobile traffic use and areas for heavy-duty truck traffic. For design purposes, an assumed equivalent daily load axle (EDLA) rating of 10 is used in the automobile areas and an EDLA rating of 50 in the heavy-duty areas. A Hveem stabilometer R-value of 10 was assumed and used in design. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 13 Hot mix asphalt (HMA) underlain by aggregate base course with a fly ash treated subgrade, or a non-reinforced concrete pavement may be feasible options for the proposed on-site paved sections. HMA pavements may show rutting and distress in areas of heavy traffic, heavy truck routes (including trash trucks) or in truck loading and turning areas. Concrete pavements should be considered in those areas. These areas would include the ATM drive through areas. Suggested pavement sections are provided in the table below. The outlined pavement sections are minimums and thus, periodic maintenance should be expected. TABLE IV: RECOMMENDED MINIMUM PAVEMENT SECTIONS Automobile Parking Heavy Duty Areas 18-kip EDLA 18-kip ESAL Reliability Resilient Modulus PSI Loss 10 73,000 75% 3562 2.5 50 365,000 85% 3562 2.2 Design Structure Number 2.60 3.55 Composite Section – Option A (assume Stable Subgrade) Hot Mix Asphalt Aggregate Base Course Structure Number 4" 8" (2.64) 5-1/2" 11" (3.63) Composite Section with Fly Ash Treated Subgrade Hot Mix Asphalt Aggregate Base Course Fly Ash Treated Subgrade (assume half-credit) Structure Number 3½" 4" 12" (2.58) 5" 7" 12" (3.57) PCC (Non-reinforced) – placed on a stable subgrade 5½" 7" We recommend aggregate base be graded to meet a Class 5 or Class 6 aggregate base. Aggregate base should be adjusted in moisture content and compacted to achieve a minimum of 95% of standard Proctor maximum dry density. HMA should be graded to meet a SX (75) or S (75) with PG 58-28 binder. The HMA should be Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 14 Portland cement concrete should be an acceptable exterior pavement mix with a minimum 28-day compressive strength of 4,200 psi and should be air entrained. The recommended pavement sections are minimums; periodic maintenance should be expected. Longitudinal and transverse joints should be provided as needed in concrete pavements for expansion/contraction and isolation. The location and extent of joints should be based upon the final pavement geometry. Sawed joints should be cut in accordance with ACI recommendations. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. Since the cohesive soils on the site have some movement potential, pavements could crack in the future primarily because of the volume change of the soils when subjected to changes in moisture content of the subgrades. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. Stabilization of the subgrades will reduce the potential for cracking of the pavements. The collection and diversion of surface drainage away from paved areas is critical to the satisfactory performance of the pavement. Drainage design should provide for the removal of water from paved areas in order to reduce the potential for wetting of the subgrade soils. Long-term pavement performance will be dependent upon several factors, including maintaining subgrade moisture levels and providing for preventive maintenance. The following recommendations should be considered the minimum:  The subgrade and the pavement surface should be adequately sloped to promote proper surface drainage.  Install pavement drainage surrounding areas anticipated for frequent wetting (e.g. garden centers, wash racks)  Install joint sealant and seal cracks immediately.  Seal all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration to subgrade soils.  Place and compact low permeability backfill against the exterior side of curb and gutter. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 15 Preventive maintenance should be planned and provided for through an on-going pavement management program. Preventive maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment. Preventive maintenance consists of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Preventive maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Prior to implementing any maintenance, additional engineering observation is recommended to determine the type and extent of preventive maintenance. Site grading is generally accomplished early in the construction phase. However as construction proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or rainfall. As a result, the pavement subgrade may not be suitable for pavement construction and corrective action will be required. The subgrade should be carefully evaluated at the time of pavement construction for signs of disturbance, rutting, or excessive drying. If disturbance has occurred, pavement subgrade areas should be reworked, moisture conditioned, and properly compacted to the recommendations in this report immediately prior to paving. If during or after placement of the stabilization or initial lift of pavement, the area is observed to be yielding under vehicle traffic or construction equipment, it is recommended that EEC be contacted for additional alternative methods of stabilization, or a change in the pavement section. Water Soluble Sulfates – (SO4) The water soluble sulfate (SO4) testing of the on-site subgrade materials taken during our subsurface exploration are provided in the following table below. Based on the reported sulfate contents test results, this report includes a recommendation for the CLASS or TYPE of cement for use for contact in association with the on-site subsoils. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 16 TABLE V - Water Soluble Sulfate Test Results Sample Location Description Soluble Sulfate Content (mg/kg) Soluble Sulfate Content (%) B-2, S-2 at 4’ Silty Sandy Lean Clay (CL) 330 0.03 B-3, S-2 at 9’ Silty Sandy Lean Clay (CL) 200 0.02 Based on the results as presented above, ACI 318, Section 4.2 indicates the site overburden soils have a low risk of sulfate attack on Portland cement concrete. Therefore Class 0 and/or Type I/II cement with or without the use of fly ash could be used for concrete on and below site grades within the overburden soils. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. These results are being compared to the following table. TABLE VI Requirements to Protect Against Damage to Concrete by Sulfate Attack from External Sources of Sulfate Severity of Sulfate exposure Water-soluble sulfate (SO4) in dry soil, percent Water-cement ratio, maximum Cementitious material Requirements Class 0 0.00 to 0.10% 0.45 Class 0 Class 1 0.11 to 0.20% 0.45 Class 1 Class 2 0.21 to 2.00% 0.45 Class 2 Class 3 2.01 of greater 0.45 Class 3 Utilities Cuts extending into the near surface soils would be expected to stand on relatively steep temporary slopes. However, cuts extending to greater depths could expose soft, wet, pumping soils and groundwater. The soft, wet cohesive soils may be unstable in the trench excavations. Stabilization of the sides and bottoms of some of the trenches and at least some dewatering should be anticipated for deeper utilities. Although the excavated soils could be used for backfilling the utility excavations, moisture conditioning of those soils will be necessary before the excavated material can be used for backfilling. Backfill material should be placed and compacted as recommended in the section “General Considerations and Site Preparation”. Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 17 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. Other Considerations Positive drainage should be developed away from the structure and pavement areas with a minimum slope of 1-inch per foot for the first 10-feet away from the improvements in landscape areas. Care should be taken in planning of landscaping adjacent to the building and parking and drive areas to avoid features which would pond water adjacent to the pavement, foundations or stemwalls. Placement of plants which require irrigation systems or could result in fluctuations of the moisture content of the subgrade material should be avoided adjacent to site improvements. Lawn watering systems should not be placed within 5 feet of the perimeter of the building and parking areas. Spray heads should be designed not to spray water on or immediately adjacent to the structure or site pavements. Roof drains should be designed to discharge at least 5 feet away from the structure and away from the pavement areas. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations, which may occur between borings or across the site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical Earth Engineering Consultants, LLC Subsurface Exploration Report Warren Federal Credit Union - East Lot Development Rigden Farm 16th Filing EEC Project No. 1152043 June 16, 2015 Page 18 engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of the RB+B Architects, Inc., for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. Earth Engineering Consultants, LLC DRILLING AND EXPLORATION DRILLING & SAMPLING SYMBOLS: SS: Split Spoon ‐ 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample ST: Thin‐Walled Tube ‐ 2" O.D., unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler ‐ 2.42" I.D., 3" O.D. unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit = 4", N, B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2‐inch O.D. split spoon, except where noted. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS : While Sampling WCI: Wet Cave in WD : While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION Soil Classification is based on the Unified Soil Classification system and the ASTM Designations D‐2488. Coarse Grained Soils have move than 50% of their dry weight retained on a #200 sieve; they are described as: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are described as : clays, if they are plastic, and silts if they are slightly plastic or non‐plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse grained soils are defined on the basis of their relative in‐ place density and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff (CL); silty sand, trace gravel, medium dense (SM). CONSISTENCY OF FINE‐GRAINED SOILS Unconfined Compressive Strength, Qu, psf Consistency < 500 Very Soft 500 ‐ 1,000 Soft 1,001 ‐ 2,000 Medium 2,001 ‐ 4,000 Stiff 4,001 ‐ 8,000 Very Stiff 8,001 ‐ 16,000 Very Hard RELATIVE DENSITY OF COARSE‐GRAINED SOILS: N‐Blows/ft Relative Density 0‐3 Very Loose 4‐9 Loose 10‐29 Medium Dense 30‐49 Dense 50‐80 Very Dense 80 + Extremely Dense PHYSICAL PROPERTIES OF BEDROCK DEGREE OF WEATHERING: Slight Slight decomposition of parent material on joints. May be color change. Moderate Some decomposition and color change throughout. High Rock highly decomposed, may be extremely broken. Group Symbol Group Name Cu≥4 and 1<Cc≤3 E GW Well-graded gravel F Cu<4 and/or 1>Cc>3 E GP Poorly-graded gravel F Fines classify as ML or MH GM Silty gravel G,H Fines Classify as CL or CH GC Clayey Gravel F,G,H Cu≥6 and 1<Cc≤3 E SW Well-graded sand I Cu<6 and/or 1>Cc>3 E SP Poorly-graded sand I Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I inorganic PI>7 and plots on or above "A" Line CL Lean clay K,L,M PI<4 or plots below "A" Line ML Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,N Liquid Limit - not dried Organic silt K,L,M,O inorganic PI plots on or above "A" Line CH Fat clay K,L,M PI plots below "A" Line MH Elastic Silt K,L,M organic Liquid Limit - oven dried Organic clay K,L,M,P Liquid Limit - not dried Organic silt K,L,M,O Highly organic soils PT Peat (D30)2 D10 x D60 GW-GM well graded gravel with silt NPI≥4 and plots on or above "A" line. GW-GC well-graded gravel with clay OPI≤4 or plots below "A" line. GP-GM poorly-graded gravel with silt PPI plots on or above "A" line. GP-GC poorly-graded gravel with clay QPI plots below "A" line. SW-SM well-graded sand with silt SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay Earth Engineering Consultants, LLC IIf soil contains >15% gravel, add "with gravel" to group name JIf Atterberg limits plots shaded area, soil is a CL- ML, Silty clay Unified Soil Classification System 1 2 B-5 B-6 B-3 B-4 B-2 B-1 Boring Location Diagram Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado EEC Project Number: 1152043 Date: June 2015 B-1 thru B-4: Foundation Related Test Borings 15-25' EARTH ENGINEERING CONSULTANTS, LLC Legend B-5 thru B-6: Pavement Related Test Borings 10' 1 Site Photos (Photos taken in approximate location, in direction of arrow) RIGDEN FARMS – WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO EEC PROJECT NO. 1152043 JUNE 2015 PHOTO #2 PHOTO #1 DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 stiff _ _ 3 _ _ 4 _ _ CS 5 8 9000 9.8 86.6 36 20 82.6 600 psf 0.1% _ _ 6 _ _ 7 _ _ SANDY LEAN CLAY (CL) 8 red / brown _ _ stiff 9 _ _ SS 10 9 9000+ 16.2 _ _ 11 _ _ 12 _ _ 13 _ _ 14 with traces of gravel _ _ CS 15 8 4500 15.1 115.3 BOTTOM OF BORING DEPTH 15.0' _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 stiff to very stiff _ _ % @ 150 psf with calcareous deposits CS 3 10 9000+ 15.8 100.7 35 18 84.9 2.4% _ _ 4 _ _ SS 5 10 9000+ 10.1 _ _ 6 red / brown _ _ very stiff to hard 7 _ _ 8 _ _ 9 _ _ % @ 1000 psf Lean Clay (CL) CS 10 40 9000+ 13.7 106.9 40 25 97 5000 psf 2.5% _ _ 11 _ _ SANDY LEAN CLAY (CL) 12 brown _ _ stiff 13 _ _ 14 _ _ SS 15 8 6000 14.8 _ _ 16 _ _ SAND & GRAVEL (SP/GP) 17 brown _ _ medium dense to dense 18 _ _ 19 _ _ SS 20 -- 11.6 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ CLAYSTONE / SILTSTONE / SANDSTONE SS 25 50 -- 15.5 BOTTOM OF BORING DEPTH 25.5' _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 stiff to very stiff _ _ 3 _ _ 4 _ _ CS 5 13 9000+ 8.7 106.0 800 psf 0.4% _ _ 6 _ _ SANDY LEAN CLAY (CL) 7 red / brown _ _ very stiff to medium stiff 8 _ _ 9 _ _ SS 10 28 9000+ 12.8 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ CS 15 7 3500 18.2 109.0 _ _ 16 _ _ 17 _ _ SAND & GRAVEL (SP/GP) 18 brown _ _ medium dense to dense 19 _ _ SS 20 50/9" -- 14.0 _ _ BOTTOM OF BORING DEPTH 20.5' 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 stiff _ _ % @ 150 psf CS 3 14 9000+ 15.6 110.2 1000 psf 1.1% _ _ 4 _ _ SS 5 13 9000+ 10.1 _ _ 6 _ _ 7 _ _ SANDY LEAN CLAY (CL) 8 red / brown _ _ stiff to medium stiff 9 _ _ CS 10 17 9000+ 13.2 109.3 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 7 1500 19.8 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 medium stiff _ _ % @ 150 psf CS 3 6 1000 18.4 103.2 500 psf 0.4% _ _ 4 _ _ SS 5 6 6000 18.2 _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 4 5000 13.6 _ _ BOTTOM OF BORING DEPTH 10.5' 11 _ _ 12 _ _ 13 _ _ 14 _ _ 15 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION _ _ 1 LEAN CLAY with SAND (CL) _ _ brown 2 very stiff to stiff _ _ % @ 150 psf CS 3 16 9000+ 15.1 114.5 650 psf 0.8% _ _ 4 _ _ SS 5 14 4000 17.0 _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 8 9000+ 12.9 _ _ BOTTOM OF BORING DEPTH 10.5' 11 _ _ 12 _ _ 13 _ _ 14 _ _ 15 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Lean Clay with Sand (CL) Sample Location: Boring 1, Sample 1, Depth 4' Liquid Limit: 36 Plasticity Index: 20 % Passing #200: 82.6% Beginning Moisture: 9.8% Dry Density: 86.8 pcf Ending Moisture: 30.0% Swell Pressure: 500 psf % Swell @ 500: 0.1% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -12.0 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand (CL) Sample Location: Boring 2, Sample 1, Depth 2' Liquid Limit: 35 Plasticity Index: 18 % Passing #200: 84.9% Beginning Moisture: 15.8% Dry Density: 98.4 pcf Ending Moisture: 22.7% Swell Pressure: % Swell @ 150: 2.4% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Red / Brown Lean Clay (CL) Sample Location: Boring 2, Sample 3, Depth 9' Liquid Limit: 40 Plasticity Index: 25 % Passing #200: 97.0% Beginning Moisture: 13.7% Dry Density: 115.2 pcf Ending Moisture: 17.8% Swell Pressure: 5000 psf % Swell @ 500: 2.5% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand (CL) Sample Location: Boring 3, Sample 1, Depth 4' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - Beginning Moisture: 8.7% Dry Density: 101 pcf Ending Moisture: 22.6% Swell Pressure: 800 psf % Swell @ 500: 0.4% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand (CL) Sample Location: Boring 4, Sample 1, Depth 2' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - Beginning Moisture: 15.6% Dry Density: 108.8 pcf Ending Moisture: 20.3% Swell Pressure: 1000 psf % Swell @ 150: 1.1% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand (CL) Sample Location: Boring 5, Sample 1, Depth 2' Liquid Limit: 35 Plasticity Index: 20 % Passing #200: 80.9% Beginning Moisture: 18.4% Dry Density: 106.6 pcf Ending Moisture: 19.8% Swell Pressure: 500 psf % Swell @ 150: 0.4% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand (CL) Sample Location: Boring 6, Sample 1, Depth 2' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - Beginning Moisture: 15.1% Dry Density: 114.7 pcf Ending Moisture: 17.2% Swell Pressure: 650 psf % Swell @ 150: 0.8% Rigden Farms - Warren FCU East Lot Development Fort Collins, Colorado 1152043 June 2015 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING None RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-6 JUNE 2015 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING None RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-5 JUNE 2015 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING None RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-4 JUNE 2015 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING 16.5' RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-3 JUNE 2015 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING 16' RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-2 JUNE 2015 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/1/2015 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/1/2015 WHILE DRILLING None RIGDEN FARMS - WARREN FCU EAST LOT DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1152043 LOG OF BORING B-1 JUNE 2015 Soil Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Sands 50% or more coarse fraction passes No. 4 sieve Fine-Grained Soils 50% or more passes the No. 200 sieve <0.75 OL Gravels with Fines more than 12% fines Clean Sands Less than 5% fines Sands with Fines more than 12% fines Clean Gravels Less than 5% fines Gravels more than 50% of coarse fraction retained on No. 4 sieve Coarse - Grained Soils more than 50% retained on No. 200 sieve CGravels with 5 to 12% fines required dual symbols: Kif soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel", whichever is predominant. <0.75 OH Primarily organic matter, dark in color, and organic odor ABased on the material passing the 3-in. (75-mm) sieve ECu=D60/D10 Cc= HIf fines are organic, add "with organic fines" to group name LIf soil contains ≥ 30% plus No. 200 predominantly sand, add "sandy" to group name. MIf soil contains ≥30% plus No. 200 predominantly gravel, add "gravelly" to group name. DSands with 5 to 12% fines require dual symbols: BIf field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. FIf soil contains ≥15% sand, add "with sand" to GIf fines classify as CL-ML, use dual symbol GC- CM, or SC-SM. Silts and Clays Liquid Limit less than 50 Silts and Clays Liquid Limit 50 or more 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 80 90 100 110 PLASTICITY INDEX (PI) LIQUID LIMIT (LL) ML OR OL MH OR OH For Classification of fine-grained soils and fine-grained fraction of coarse-grained soils. Equation of "A"-line Horizontal at PI=4 to LL=25.5 then PI-0.73 (LL-20) Equation of "U"-line Vertical at LL=16 to PI-7, then PI=0.9 (LL-8) CL-ML HARDNESS AND DEGREE OF CEMENTATION: Limestone and Dolomite: Hard Difficult to scratch with knife. Moderately Can be scratched easily with knife. Hard Cannot be scratched with fingernail. Soft Can be scratched with fingernail. Shale, Siltstone and Claystone: Hard Can be scratched easily with knife, cannot be scratched with fingernail. Moderately Can be scratched with fingernail. Hard Soft Can be easily dented but not molded with fingers. Sandstone and Conglomerate: Well Capable of scratching a knife blade. Cemented Cemented Can be scratched with knife. Poorly Can be broken apart easily with fingers. Cemented designed in accordance with LCUASS design criteria. HMA should be compacted to achieve 92 to 96% of the mix's theoretical maximum specific gravity (Rice Value).