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HomeMy WebLinkAbout3425 SOUTH SHIELDS - PDP - PDP160026 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO EEC PROJECT NO. 1162056 Prepared for: Brinkman Partners 3528 Precision Drive, Suite 100 Fort Collins, Colorado 80528 Attn: Mr. Scott Ranweiller, Development Manager (scott.ranweiller@brinkmanpartners.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 30, 2016 Brinkman Partners 3528 Precision Drive, Suite 100 Fort Collins, Colorado 80528 Attn: Mr. Scott Ranweiller, Development Manager (scott.ranweiller@brinkmanpartners.com) Re: Geotechnical Subsurface Exploration Report 3425 South Shields Street Apartments Fort Collins, Colorado EEC Project No. 1162056 Mr. Ranweiller: Enclosed, herewith, are the results of the geotechnical subsurface exploration completed by Earth Engineering Consultants, LLC (EEC) personnel for the referenced project. For this exploration, a total of nine (9) soil borings were drilled at the approximate locations as indicated on the enclosed Test Boring Location Diagram. Three (3) of those borings were completed in 2007 as a part of our preliminary assessment of this site, and six (6) additional borings were completed on June 22, 2016. The borings were extended to depths of approximately 15 to 35 feet below existing site grades. Individual boring logs, including results of laboratory testing, are included as a part of the attached report. This exploration was completed in general accordance with our proposal dated June 2, 2016. We understand this project involves the construction of three (3) multi-unit residential apartment buildings with associated pavements. Foundation loads for the structures are expected to be light to moderate and floor loads are expected to be light. Based on the materials observed within the test borings, expected site grading and the anticipated foundation loads, we believe the apartment buildings could be supported on post-tensioned slab- on-grade foundation systems or conventional type spread footings bearing on native materials or a zone of engineered fill material placed and compacted as described within the enclosed report. In general, it appears the in-situ site materials or similar import fill materials could be used for support of interior slab-on-grades, exterior flatwork, and site pavements. Care will be needed during construction to assess the swell potential of the in-place cohesive soils and mitigate GEOTECHNICAL SUBSURFACE EXPLORATION REPORT 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO EEC PROJECT NO. 1162056 June 30, 2016 INTRODUCTION The geotechnical subsurface exploration for the proposed three (3) building apartment development project at 3425 South Shields Street in Fort Collins, Colorado, has been completed. For this exploration, six (6) supplemental soil borings were drilled on June 22, 2016 within the proposed building areas at the site. Those borings were extended to approximate depths of 15 to 25 feet below existing site grades. Three (3) borings to depths of approximately 20 to 35 feet were completed on this site in 2007 as a part of a preliminary site exploration. Copies of the data developed as a part of the preliminary exploration are included with this report along with the data developed in the more recent exploration. This exploration was completed in general accordance with our proposal dated June 2, 2016. We understand, the proposed development will generally include the construction of three (3) multi- unit residential apartments with associated paved drive and parking. The apartment buildings will be two to three-story, wood-frame, slab-on-grade (no basement) buildings. Foundation loads for the structures are expected to be light with continuous wall loads less than 4 kips per lineal foot and individual column loads less than 150 kips. Floor loads are expected to be light. Paved drive and parking for the development is expected to carry light to moderate traffic consisting predominately of private autos and light trucks. The purpose of this report is to described the subsurface conditions encountered in the test borings, analyze and evaluate the test data and provide geotechnical recommendations concerning design and construction of foundations, support of floor slabs, exterior flatwork, and pavements and development of other earth related features for the proposed site improvements. EXPLORATION AND TESTING PROCEDURES The test borings were completed 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 Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 2 obtained using split barrel and California barrel sampling procedures in general accordance with ASTM Specifications D1586 and D3550, respectively. In the split barrel and California barrel sampling procedures, standard sampling spoons are advanced into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split barrel and California barrel samplers is recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency of cohesive soils. In the California barrel sampling procedure, relatively intact samples are obtained in removable brass liners. All samples obtained in the field were sealed and returned to our laboratory for further examination, classification and testing. Moisture content tests were completed on each of the recovered samples. Atterberg limits and washed sieve analysis tests were completed on selected samples to evaluate the quantity and plasticity of fines in the subgrades. Swell/consolidation tests were completed to evaluate the potential for the subgrade materials to change volume with variation in moisture and load. Water soluble sulfate tests were completed on selected samples. Results of the outlined tests are indicated on the attached boring logs and summary sheets. As part of the testing program, all samples were examined in the laboratory and classified in general accordance with the attached General Notes and the Unified Soil Classification System, based on the soil’s texture and plasticity. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs and a brief description of that classification system is included with this report. Classification of the bedrock was based on visual and tactual observation of disturbed samples. Coring and/or petrographic analysis may reveal other rock types. SITE AND SUBSURFACE CONDITIONS The proposed apartments will be situated at 3425 South Shields Street as indicated on the attached boring location diagram. This parcel is currently used predominately for RV and boat storage; however, includes a single family resident in the southeast corner and other single story structures in the center of the site. We understand the existing buildings will be removed as a part of the development of this site. A Google Earth diagram indicating the current building locations is included with this report. Surface drainage is generally to the north and east with total grade change on the order of 5 feet. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 3 Based on results of the field borings and laboratory testing, subsurface conditions can be generalized as follows. A surficial layer of sparse vegetation/topsoil or gravel surfaced drive/parking areas were encountered at the boring locations. Cohesive lean clay to sandy lean clay subsoils were encountered beneath the surfacing. The clay soils extended to sands and gravels at approximate depths of 9 feet below existing site grades in borings B-1, B-6 and B-7 and to the bottom of the remaining completed test borings. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil types. In-situ, the transition of materials may be gradual and indistinct. The upper essentially cohesive soils encountered beneath the surfacing materials varied from medium stiff to very stiff / medium dense in consistency, generally exhibited low swell potential and typically low bearing capacity characteristics. Higher swell was observed in the sample tested from boring B-4. The swell potential of the soils are shown on the enclosed swell-consolidation curves included with this report. The lower portion of the essentially cohesive zone encroaching into groundwater level may exhibit soft conditions with the increase in moisture content. The silty/clayey sand and gravel materials were generally medium dense. 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, both in 2007 and 2016, free water was observed at depths of approximately 16 to 17 feet below site grades. Piezometers were installed in 2007 to monitor the groundwater levels; however, we are not aware of any continuing monitoring program. The borings completed in 2016 were backfilled immediately after completion; therefore, subsequent groundwater measurements are not available for those locations. 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, which are sealed from the influence of surface water would be required to 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 Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 4 ANALYSIS AND RECOMMENDATIONS Swell – Consolidation Test Results Swell/consolidation testing is performed to evaluate the swell or collapse potential of soil or bedrock to assist in determining/evaluating foundation, floor slab and pavement design criteria. In the swell/consolidation test, samples obtained directly from the California barrel sampler are placed in a laboratory apparatus and inundated with water under a pre-established load. The swell-index is the resulting amount of swell or collapse under the initial loading condition expressed as a percent of the sample’s initial thickness. After the initial monitoring period, additional incremental loads are applied to evaluate swell pressure and/or consolidation response. For this site, we completed a total of ten (10) swell-consolidation tests, four (4) in 2007 and six (6) in 2016. The swell index values for the samples analyzed revealed swells ranging from no swell to approximately 2.3% swell with dead load of 500 psf. Results of the completed swell tests are summarized on the boring logs and provided on the attached summaries. The (-) test results indicate the tendency to consolidate upon inundation with water while the (+) test results indicate the swell. Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide uniformity in terminology between geotechnical engineers to provide a relative correlation of 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 I: 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 EEC Project No. 1162056 June 30, 2016 Page 5 Site Preparation Based on our understanding of the proposed development, we expect fills less than 3 feet may be completed to achieve design grades. In addition, the existing buildings will be razed prior to developing those portions of the project. All existing improvements including foundations, floor slabs, pavements, landscaping (including tree root systems), curb-and-gutter, flatwork/sidewalks and any undocumented fill materials should be removed from the site improvement areas. Close observation during construction is advised to identify and evaluate any in-place fills and/or any dry and desiccated or soft and wet materials. Care should be taken in the area of the gravel surfaced site access roads to assess the moisture and density of the in-place subgrade soils; repeated traffic can densify in-place subgrade soils and increase the swell potential of the subgrades. Fill materials were likely placed to develop site grades and backfill materials would have been placed adjacent to existing building foundations. After removing all improvements including any undocumented fill materials, and prior to placement of any fill and/or site improvements, we recommend the exposed soils be scarified to a depth of at least 9 inches, adjusted in moisture content to within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the material's standard Proctor maximum dry density as determined in accordance with ASTM Specification D698. Fill soils required to develop the building, pavement/flatwork and site subgrades should consist of approved, low-volume-change materials, which are free from organic matter and debris. It is our opinion the on-site essentially cohesive soils or similar import soils could be used as fill in these areas, provided adequate moisture treatment and compaction procedures are followed. Granular structural fill materials could also be used to develop the site grades; recommendations outlined in this report assume subgrades consisting of materials similar to the site sandy lean clay. Placement of defined depths of granular structural fill could result in alternative recommendations such as reduced pavement thickness or increased bearing capacity. We recommend the fill soils be placed in loose lifts not to exceed 9 inches thick and adjusted in moisture content and compacted as recommended for the scarified soils. If the site lean clay soils or similar import materials are used as fill material, care will be needed to maintain the recommended moisture content prior to and during construction of overlying improvements. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 6 Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade materials. 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. As indicated on the attached boring logs and laboratory summary sheets, relatively low swelling cohesive soils are present on this site. However, swell potential can change with changes in moisture content and density of the subgrade materials. This report provides recommendations to help mitigate the effects of soil shrinkage or expansion for the cohesive subgrades. Even if these procedures are followed, some movement and at least minor cracking in the site improvements should be anticipated. The severity of cracking and other cosmetic damage such as uneven floor slabs/exterior flatwork will probably increase if any modification of the site results in excessive drying and/or wetting of the site soils. 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 expensive measures are used during construction. We would be pleased to discuss other construction alternatives with you upon request. Areas of deeper fills such as utility backfill may experience settlement from within the placed fill materials. Settlement on the order of 1 to 1.5% of the fill depth would be estimated. The rate of settlement will be dependent on the type of fill material placed and construction methods. Granular soils will consolidate essentially immediately upon placement of overlying loads. Cohesive soils will consolidate at a significantly slower rate. 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 systems were evaluated for use on the site:  Conventional Spread Footings  Post-Tensioned Slab-On-Grade Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 7 Conventional Spread Footing Foundations The native undisturbed lean clay to clayey sand generally exhibited low swell potential and low to moderate bearing characteristics. Placed fill materials are/will be present on the site; either documentation of the fill placement densities should be reviewed to confirm suitability of those fill materials to support the proposed improvements or those materials should be removed as recommended in the section Site Preparation. Subgrade and bearing soils should also be closely observed at the time of construction to evaluate in-place materials and assess the suitability of those soils for support. Based on the materials observed in the test borings, we expect conventional type spread footings could be used to support the proposed slab on grade buildings provided the footings are placed on approved native subgrade material or moisture/density controlled fill material and the maximum anticipated wall and column loads do not exceed those presented herein. If actual design loads exceed the assumed values as previously presented, we should be consulted to provide supplemental design criteria, possibly including alternative foundations. Footings bearing on approved native subsoils or moisture/density conditioned soils could be designed for a maximum net allowable total load bearing pressure of 2,000 psf. The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load should include full dead and live loads. Footings should be proportioned to reduce differential foundation movement. We estimate the total long term settlement of footings designed as outlined above would be less than one inch. Greater settlements could occur if foundations are supported on soft or loose fill soils. The backfill soils adjacent to the foundations should be placed in loose lifts not to exceed 9 inches in thickness, moisture conditioned to ±2% of the material’s standard Proctor optimum moisture content, and mechanically compacted to be at least 95% of standard Proctor maximum dry density, ASTM D698. After placement of the fill materials, care should be taken to avoid wetting or drying of those materials. Bearing materials, which are loosened or disturbed by the construction activities, or Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 8 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. Exterior foundations and foundations in unheated areas should be located at least 30 inches below adjacent exterior grade to provide frost protection. We recommend formed continuous footings have a minimum width of 12 inches and isolated column foundations have a minimum width of 24 inches. Post-Tensioned Slab Foundation The results of our field exploration and laboratory testing completed indicate the upper cohesive clay subsoils have generally low swell potential and low to moderate bearing capacity. Based on the subsurface conditions encountered and the expected fill materials across the site, we expect the proposed apartment buildings could be supported by post-tensioned slab-on-grade foundations that are supported/bear on a zone of engineered/controlled fill materials placed and compacted as outlined in the Site Preparation section of this report or on acceptable underlying native soils. The design parameters provided below assume subgrade materials outlined under Site Preparation. Outlined below are the post-tensioned slab (PTS) design criteria based on the subsurface conditions, anticipated cohesive fill placement, and information provided in the 3rd Edition of the Post- Tensioning Institutes design manual. Post-tensioned slabs, thickened or turn-down edges, and/or interior beams should be designed and constructed in accordance with the appropriate design criteria. Table II – Post-Tension Slab (PTS) Design Criteria Post-Tension Slab (PTS) – 3rd Edition Design Parameters Maximum Allowable Bearing Pressure, psf 2000 Edge Moisture Variation Distance, em Center Lift Condition, ft 8.2 Edge Lift Condition, ft 4.2 Differential Soil Movement, ym Center Lift Condition, in 0.2 Edge Lift Condition, in 0.7 Slab-Subgrade friction coefficient,  on polyethylene sheeting 0.75 on cohesionless soils (sands) 1.0 on cohesive soils (clays) 2.0 Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 9 Seismic The site soil conditions consist of greater than 35 feet of overburden soils. For those site conditions, the International Building Code indicates a Seismic Site Classification of D. Lateral Earth Pressures For any area of the proposed development having below grade construction, such as retaining walls, 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 such as below grade building walls. Passive pressures and friction between the footing and bearing soils could be used for design of resistance to movement of retaining walls. Coefficient values for backfill with anticipated types of soils for calculation of active, at-rest and passive earth pressures are provided in the table below. Equivalent fluid pressure is equal to the coefficient times the appropriate soil unit weight. Those coefficient values are based on horizontal backfill with backfill soils consisting of essentially on-site cohesive subsoils, or approved imported granular materials with friction angles of 25 and 35 degrees respectively. 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. 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. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 10 Table III – Lateral Earth Pressure Design Values Soil Type On-Site Low Plasticity Cohesive Imported Medium Dense Granular Wet Unit Weight 120 135 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 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 prior to construction. 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 into the system. Where necessary, appropriate hydrostatic load values should be used for design. Floor Slabs Conventional slab-on-grade construction could be considered for the site provided certain precautions are adhered to. To reduce floor slab movement, we recommend the proposed floor slab on grade bear on reconditioned site soils or properly placed and compacted engineered fill material as outlined under Site Preparation. It is our opinion the on-site essentially cohesive soils could be used as fill in these areas, provided adequate moisture treatment and compaction procedures are followed. If the site lean clay soils or similar import materials are used as fill material, care will be needed to maintain the recommended moisture content prior to and during construction of overlying improvements. This procedure will not fully eliminate the possibilities of slab movement; but movements should be reduced and tend to be more uniform. For structural design of concrete slabs-on-grade, a modulus of subgrade reaction (k-value) of 100 pounds per cubic inch (pci) may be used for floors supported on compacted on-site or similar import soils. A modulus of 200 pci could be used for floors supported on non-expansive imported granular structural fill material. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 11 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 imported structural fill material. Pavements We expect the site pavements will include areas designated for low volume automobile traffic/parking and limited areas of heavier/higher volume traffic. For heavier traffic areas an assumed equivalent daily load axle (EDLA) of 25 was selected, and for automobile/parking areas an EDLA of 10 was selected. Proof rolling and recompacting the subgrade is recommended immediately prior to placement of the aggregate road base section. Soft or weak areas delineated by the proof rolling operations should be undercut or stabilized in-place to achieve the appropriate subgrade support. Based on the subsurface conditions encountered at the site and the laboratory test results, it is recommended the on-site private drives and parking areas be designed using an R-value of 10. Moisture conditioned/engineered fill material may be placed in areas to develop the subgrades. Pumping conditions could develop within a moisture treatment process of on-site or imported essentially cohesive soils. Subgrade stabilization may be needed to develop a stable subgrade for paving. A stabilized subgrade could also reduce the thickness of the overlying pavement structure. Stabilization could include incorporating at least 12 percent (by weight) Class C fly ash into the upper 12 inches of subgrade. Hot Mix Asphalt (HMA) underlain by crushed aggregate base course with or without a fly ash treated subgrade, and non-reinforced concrete pavement could be considered as alternatives for the proposed on-site paved sections. Eliminating the risk of movement within the proposed pavement section may not be feasible due to the characteristics of the subsurface materials; but it may be possible to further reduce the risk of movement if significantly more expensive subgrade stabilization measures are used during construction. We would be pleased to discuss other construction alternatives with you upon request. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 12 Pavement design methods are intended to provide structural sections with adequate thickness over a particular subgrade such that wheel loads are reduced to a level the subgrade can support. The support characteristics of the subgrade for pavement design do not account for shrink/swell movements of an expansive clay subgrade or consolidation of a wetted subgrade. Thus, the pavement may be adequate from a structural standpoint, yet still experience cracking and deformation due to shrink/swell related movement of the subgrade. Therefore, it’s important to minimize moisture changes in the subgrade to reduce shrink/swell movements. Recommended pavement sections are provided below in TABLE IV. The hot bituminous pavement (HBP) could be grading SX (75) or S (75) with PG 58-28 oil. The aggregate base should be Class 5 or Class 6 base. Portland cement concrete should be an exterior pavement mix with a minimum 28- day compressive strength of 4000 psi and should be air entrained. HMA pavements may show rutting and distress in truck loading and turning areas. Concrete pavements should be considered in those areas. The recommended pavement sections are minimums and periodic maintenance should be expected. TABLE IV – RECOMMENDED PAVEMENT SECTIONS Local Residential Roadways/Parking Minor Collectors / Heavy Duty Roadways EDLA Reliability Resilient Modulus PSI Loss 10 75% 3562 psi 2.5 25 85% 3562 psi 2.2 Design Structure Number 2.60 3.20 Composite Section without Fly Ash – Option A Hot Mix Asphalt (HMA) Aggregate Base Course Design Structure Number 4ʺ 8ʺ (2.64) 5-1/2ʺ 8ʺ (3.30) Composite Section with Fly Ash – Option B Hot Mix Asphalt (HMA) Aggregate Base Course ABC Fly Ash Treated Subgrade Design Structure Number 4ʺ 6 ʺ 12″ (3.02) 4ʺ 8ʺ 12ʺ (3.24) Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 13 Since the cohesive soils on the site have some shrink/swell potential, pavements could crack in the future primarily because of the volume change of the soils when subjected to an increase in moisture content to the subgrade. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. 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 and 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  Placing compacted, low permeability backfill against the exterior side of curb and gutter  Placing curb, gutter, and/or sidewalk directly on approved proof rolled subgrade soils 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. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 14 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, such as but not limited to drying, or rutting. 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. Please note that 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. Other Considerations Positive drainage should be developed away from the structures 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 (if required) adjacent to the building to avoid features which would pond water adjacent to the 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. Irrigation systems should not be placed within 5 feet of the perimeter of the buildings and parking areas. Spray heads should be designed not to spray water on or immediately adjacent to the structures or site pavements. Roof drains should be designed to discharge at least 5 feet away from the structures and away from the pavement areas. Excavations into the on-site clays and proposed import materials can be expected to stand on relatively steep temporary slopes during construction. However, if excavations extend into the underlying sand and gravel layers and/or underlying groundwater, caving soils may be encountered. The individual contractor(s) should be made responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards. Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 15 Water Soluble Sulfates The water soluble sulfate (SO4) testing of the on-site overburden materials taken during our subsurface exploration are provided in Table V below. TABLE V - Water Soluble Sulfate Test Results Sample Location Description Soluble Sulfate Content (mg/kg) Soluble Sulfate Content (%) B-4, S-1 @ 4' Sandy Lean Clay 120 0.01 B-9, S-2 @ 9' Clayey Sand 190 0.02 Based on the results as presented in Table V 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 sulfate exposure could be used for concrete on and below site grade within the on-site overburden soils. Import materials should be evaluated to determine sulfate levels. 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 engineer be retained for testing and observations during earthwork phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of Brinkman Partners for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, expressed 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 Earth Engineering Consultants, LLC EEC Project No. 1162056 June 30, 2016 Page 16 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-2 B-4 B-5 B-6 B-3 B-7 B-1 B-8 B-9 Figure 1: Boring Location Diagram 3425 South Shields Street Apartments Fort Collins, Colorado EEC Project Number: 1162056 Date: June 2016 EARTH ENGINEERING CONSULTANTS, LLC B-1 thru B-3: Approximate Locations of 3 Preliminary Borings Drilled in 2007 Legend B-4 thru B-9: Approximate Boring Locations Drilled June 2016 1 Site Photos (Photos taken in approximate location, in direction of arrow) S Shields St Figure 2: Site Diagram 3425 South Shields Street Apartments Fort Collins, Colorado EEC Project Number: 1162056 Date: June 2016 EARTH ENGINEERING CONSULTANTS, LLC DATE: RIG TYPE: CME45 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF TOPSOIL & VEGETATION _ _ LEAN CLAY WITH SAND (CL) 1 brown / red _ _ 2 SANDY LEAN CLAY (CL) ST _ _ -- 6000 22.7 38 14 53.4 <500 psf None red 3 loose _ _ with scattered gravel 4 _ _ CS 5 9 3000 9.7 106.0 _ _ 6 _ _ 7 _ _ 8 _ _ 9 SAND & GRAVEL _ _ red / brown / grey SS 10 24 -- 4.4 medium dense _ _ with clay 11 _ _ 12 _ _ 13 _ _ 14 _ _ SANDY LEAN CLAY (CL) SS 15 4 -- 27.6 red _ _ 16 with scattered gravel _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 4 -- 16.0 _ _ BOTTOM OF BORING DEPTH 20.5' 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 Earth Engineering Consultants 3425 S. SHIELDS STREET FORT COLLINS, COLORADO DATE: RIG TYPE: CME45 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF TOPSOIL & VEGETATION _ _ 1 LEAN CLAY WITH SAND (CL) _ _ brown / red 2 stiff to very stiff _ _ with calcareous deposits and scattered gravel CS 3 8 9000+ 10.2 91.5 37 18 61.6 800 psf 0.4% _ _ 4 _ _ SS 5 20 -- 8.8 _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 10 9000+ 16.1 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ red SS 15 4 500 18.8 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 2 -- 25.3 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ increase in sand with depth SS 25 14 7000 13.1 continued on page 2 of 2 Earth Engineering Consultants 3425 S. SHIELDS STREET DATE: RIG TYPE: CME45 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF continued from page 1 of 2 26 _ _ SILTY SANDY LEAN CLAY (CL) 27 red _ _ 28 _ _ 29 _ _ 30 _ _ 31 CLAYSTONE / SANDSTONE _ _ olive / brown / rust 32 _ _ 33 _ _ 34 _ _ CS 35 50/4" 9000+ 11.4 128.1 34 16 93.1 2800 psf 1.7% BOTTOM OF BORING DEPTH 35.0' _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 Earth Engineering Consultants N/A WHILE DRILLING 16.0' AFTER DRILLING DATE: RIG TYPE: CME45 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF TOPSOIL & VEGETATION _ _ SANDY LEAN CLAY (CL) 1 brown _ _ 2 CLAYEY SAND (SC) _ _ red 3 medium dense to dense _ _ with calcareous deposits 4 _ _ CS 5 15 9000+ 14.8 101.9 32 14 48.1 800 psf 0.3% _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ increase in sand with depth SS 10 6 -- 8.6 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 7 2000 19.3 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 continued on page 2 of 2 Earth Engineering Consultants FINISH DATE DATE: RIG TYPE: CME45 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF continued from page 1 of 2 26 _ _ SANDY LEAN CLAY (CL) 27 red _ _ stiff to very stiff 28 with scattered gravel _ _ 29 _ _ 30 _ _ 31 olive / brown / rust _ _ 32 _ _ CS 33 50/6" 9000+ 13.4 123.8 BOTTOM OF BORING DEPTH 33.0' _ _ 34 _ _ 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 Earth Engineering Consultants FINISH DATE SURFACE ELEV 3/27/2007 SWELL / CONSOLIDATION TEST RESULTS Project: 3425 S. Shields Street Project #: Date: Fort Collins, Colorado 1072035 April 2007 Liquid Limit: 38 Plasticity Index: 14 Dry Density: 98.1 pcf % Swell @ 500 psf: % Passing #200: 53.4% Beginning Moisture: 24.5% Ending Moisture: 25.3% Swell Pressure: <500 psf None Material Description: Red Sandy Lean Clay with Scattered Gravel Sample Location: Boring 1, Sample 1, Depth 2' -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Percent Movement Load (TSF) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS Project: Project #: Date: Ending Moisture: 23.0% Swell Pressure: 800 psf 0.4% Material Description: Brown / Red Silty Sandy Lean Clay with Calcareous Deposits Sample Location: Boring 2, Sample 1, Depth 2' Fort Collins, Colorado 1072035 April 2007 Liquid Limit: 37 Plasticity Index: 18 Dry Density: 100.0 pcf % Swell @ 500 psf: % Passing #200: 61.6% 3425 S. Shields Street Beginning Moisture: 10.6% -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Percent Movement Load (TSF) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS Project: Project #: Date: Fort Collins, Colorado 1072035 April 2007 Liquid Limit: 34 Plasticity Index: 16 Dry Density: 127.5 pcf % Swell @ 500 psf: % Passing #200: 93.1% 3425 S. Shields Street Beginning Moisture: 11.1% Ending Moisture: 14.0% Swell Pressure: 2800 psf 1.7% Material Description: Olive / Brown Silty Claystone / Sandstone Sample Location: Boring 2, Sample 7, Depth 34' -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Percent Movement Load (TSF) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS Project: Project #: Date: Ending Moisture: 20.2% Swell Pressure: 800 psf 0.3% Material Description: Red Clayey Sand with Calcareous Deposits Sample Location: Boring 3, Sample 1, Depth 4' Fort Collins, Colorado 1072035 April 2007 Liquid Limit: 32 Plasticity Index: 14 Dry Density: 107.3 pcf % Swell @ 500 psf: % Passing #200: 48.1% 3425 S. Shields Street Beginning Moisture: 12.4% -10 -8 -6 -4 -2 0 2 4 6 8 10 0.01 0.1 1 10 Percent Movement Load (TSF) Water Added Consolidation 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 TOPSOIL & VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ dark brown 2 very stiff _ _ with traces of gravel CS 3 12 9000+ 13.1 109.9 37 21 58.7 4000 psf 2.3% _ _ 4 _ _ brown / red SS 5 24 9000+ 9.3 mottled _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ CLAYEY SAND (SC) CS 10 6 2000 5.2 112.2 loose _ _ with gravel 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 4 1000 21.6 _ _ 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 TOPSOIL & VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ brown / red / tan 2 very stiff to medium stiff _ _ with calcareous deposits & traces of gravel 3 _ _ 4 _ _ CS 5 18 9000+ 13.5 107.4 600 psf 0.1% _ _ 6 _ _ 7 _ _ 8 _ _ 9 with intermittent sand & gravel seams _ _ SS 10 10 7000 12.0 _ _ 11 _ _ 12 _ _ 13 _ _ 14 red / brown _ _ sand seams CS 15 20 -- 2.9 104.6 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ sand & gravel seams SS 20 6 1000 22.8 _ _ 21 _ _ 22 _ _ 23 _ _ 24 tan / olive / brown _ _ SS 25 7 2000 15.1 BOTTOM OF BORING DEPTH 25.5' _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL DATE: RIG TYPE: CME55 FOREMAN: DG AUGER TYPE: 4" CFA SPT HAMMER: AUTOMATIC SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF TOPSOIL & VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ red / tan 2 very stiff to medium stiff _ _ with traces of gravel CS 3 15 9000+ 12.3 106.0 _ _ 4 _ _ SS 5 11 9000+ 13.2 _ _ 6 _ _ 7 _ _ 8 _ _ 9 red / brown sand & gravel seams with depth _ _ CS 10 8 1000 5.3 110.7 NL NP 25.2 <500 psf None _ _ 11 _ _ 12 _ _ 13 _ _ 14 with clay seams _ _ SS 15 7 5000 4.6 _ _ 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 _ _ SANDY LEAN CLAY (CL) 1 tan / red _ _ very stiff 2 with traces of gravel _ _ 3 _ _ 4 _ _ CS 5 9 7000 21.2 102.2 <500 psf None _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SILTY SAND (SM) SS 10 10 -- 4.9 red _ _ medium dense to loose 11 with gravel _ _ 12 _ _ 13 _ _ 14 with intermittent clay zones _ _ CS 15 21 -- 3.3 111.7 _ _ 16 _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 11 -- 18.6 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ CS 25 4 BOTTOM OF BORING DEPTH 25.0' _ _ 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 TOPSOIL & VEGETATION _ _ 1 CLAYEY SAND / SANDY LEAN CLAY (SC/CL) _ _ brown / red 2 medium dense / very stiff _ _ with traces of gravel 3 _ _ 4 _ _ CS 5 11 9000+ 9.7 118.2 1000 psf 0.3% _ _ 6 _ _ 7 _ _ 8 _ _ 9 _ _ SANDY LEAN CLAY (CL) SS 10 6 6000 14.3 red _ _ very stiff 11 with traces of gravel _ _ 12 _ _ 13 _ _ 14 _ _ SILTY SANDY CLAY (CL) CS 15 7 1000 23.7 102.1 red _ _ soft 16 with intermittent sand & gravel seams _ _ 17 _ _ 18 _ _ 19 _ _ SS 20 7 1000 18.3 _ _ 21 _ _ 22 _ _ 23 _ _ 24 sandy seam _ _ CS 25 2 -- 15.8 BOTTOM OF BORING DEPTH 25.0' _ _ 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 _ _ SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) 1 brown / red / tan _ _ very stiff to medium stiff 2 mottled, with traces of gravel _ _ CS 3 17 9000+ 10.2 112.4 41 21 24.1 600 psf 0.1% _ _ 4 brown / red / tan _ _ SS 5 9 6000 25.6 _ _ 6 _ _ 7 _ _ 8 _ _ 9 with traces of gravel _ _ CS 10 16 9000+ 13.2 119.7 _ _ 11 _ _ 12 _ _ 13 _ _ 14 red _ _ with seams of sand SS 15 7 1000 17.8 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants, LLC A-LIMITS SWELL Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 13.1% Dry Density: 110.2 pcf Ending Moisture: 21.9% Swell Pressure: 4000 psf % Swell @ 500: 2.3% Sample Location: Boring 4, Sample 1, Depth 2' Liquid Limit: 37 Plasticity Index: 21 % Passing #200: 58.7% SWELL / CONSOLIDATION TEST RESULTS Material Description: Dark Brown Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 13.5% Dry Density: 107.5 pcf Ending Moisture: 20.5% Swell Pressure: 600 psf % Swell @ 500: 0.1% Sample Location: Boring 5, Sample 1, Depth 4' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Red / Tan Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 53.0% Dry Density: 75 pcf Ending Moisture: 15.4% Swell Pressure: <500 psf % Swell @ 500: None Sample Location: Boring 6, Sample 3, Depth 9' Liquid Limit: NL Plasticity Index: NP % Passing #200: 25.2% SWELL / CONSOLIDATION TEST RESULTS Material Description: Red / Brown Clayey Sand (SC) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 21.2% Dry Density: 110.9 pcf Ending Moisture: 21.3% Swell Pressure: <500 psf % Swell @ 500: None Sample Location: Boring 7, Sample 1, Depth 4' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - SWELL / CONSOLIDATION TEST RESULTS Material Description: Tan / Red Sandy Lean Clay (CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 9.7% Dry Density: 120.4 pcf Ending Moisture: 12.6% Swell Pressure: 1000 psf % Swell @ 500: 0.3% Sample Location: Boring 8, Sample 1, Depth 4' Liquid Limit: - - Plasticity Index: - - % Passing #200: - - SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Red Clayey Sand / Sandy Lean Clay (SC/CL) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added Project: Location: Project #: Date: 3425 South Shields St Apartments Fort Collins, Colorado 1162056 June 2016 Beginning Moisture: 10.2% Dry Density: 133.2 pcf Ending Moisture: 15.5% Swell Pressure: 600 psf % Swell @ 500: 0.1% Sample Location: Boring 9, Sample 1, Depth 2' Liquid Limit: 41 Plasticity Index: 21 % Passing #200: 24.1% SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown / Red / Tan Clayey Sand (SC) -10.0 -8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0 0.01 0.1 1 10 Percent Movement Load (TSF) Consolidatio Swell Water Added SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 17' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-9 JUNE 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 15.5' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-8 JUNE 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 17' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-7 JUNE 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 15.5' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-6 JUNE 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 16' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-5 JUNE 2016 SURFACE ELEV N/A 24 HOUR N/A FINISH DATE 6/22/2016 AFTER DRILLING N/A SHEET 1 OF 1 WATER DEPTH START DATE 6/22/2016 WHILE DRILLING 15.5' 3425 SOUTH SHIELDS STREET APARTMENTS FORT COLLINS, COLORADO PROJECT NO: 1162056 LOG OF BORING B-4 JUNE 2016 3/27/2007 N/A SHEET 2 OF 2 LOG OF BORING B-3.5 (PIEZOMETER) 3425 S. SHIELDS STREET FORT COLLINS, COLORADO PROJECT NO: 1072035 APRIL 2007 START DATE A-LIMITS SWELL WATER DEPTH 19.2' N/A WHILE DRILLING 16.0' AFTER DRILLING 24 HOUR SURFACE ELEV 3/27/2007 3/27/2007 N/A SHEET 1 OF 2 LOG OF BORING B-3 (PIEZOMETER) 3425 S. SHIELDS STREET FORT COLLINS, COLORADO PROJECT NO: 1072035 APRIL 2007 START DATE A-LIMITS SWELL WATER DEPTH 19.2' N/A WHILE DRILLING 16.0' AFTER DRILLING 24 HOUR 24 HOUR 3425 S. SHIELDS STREET FORT COLLINS, COLORADO PROJECT NO: 1072035 APRIL 2007 A-LIMITS SWELL WATER DEPTH 18.0' START DATE FINISH DATE SURFACE ELEV 3/27/2007 3/27/2007 N/A SHEET 2 OF 2 LOG OF BORING B-2.5 (PIEZOMETER) FORT COLLINS, COLORADO PROJECT NO: 1072035 APRIL 2007 SHEET 1 OF 2 LOG OF BORING B-2 (PIEZOMETER) WATER DEPTH 3/27/2007 3/27/2007 N/A 18.0' AFTER DRILLING A-LIMITS SWELL START DATE FINISH DATE SURFACE ELEV 24 HOUR N/A WHILE DRILLING 16.0' PROJECT NO: 1072035 APRIL 2007 LOG OF BORING B-1 (PIEZOMETER) SHEET 1 OF 1 START DATE FINISH DATE SURFACE ELEV 3/28/2007 WATER DEPTH A-LIMITS SWELL 3/27/2007 3/27/2007 N/A 16.4' N/A WHILE DRILLING 16.0' AFTER DRILLING 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 PCC (Non-reinforced) – placed on an approved subgrade 5-1/2″ 7″ 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 current ACI criteria. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer.