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HomeMy WebLinkAboutENGINES & ENERGY CONVERSION LAB - BDR - BDR120006 - REPORTS - RECOMMENDATION/REPORTSUBSURFACE EXPLORATION REPORT PROPOSED 50,000 SF MULTI-TENNANT OFFICE/LAB ADDITION CSU – ENGINES AND ENERGY CONSERVATION LAB 430 NORTH COLLEGE AVENUE FORT COLLINS, COLORADO EEC PROJECT NO. 1112015 Prepared for: Colorado State University Research Foundation 601 South Howes Street – Room 410 Fort Collins, Colorado 80521 Attn: Mr. Stuart MacMillan Prepared by: Earth Engineering Consultants, Inc. 4396 Greenfield Drive Windsor, Colorado 80550 CDN CDN##2627A-2214A-012 005 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 June 14, 2011 Colorado State University Research Foundation 601 South Howes Street – Room 410 Fort Collins, Colorado 80521 Attn: Mr. Stuart MacMillan Re: Subsurface Exploration Report Proposed 50,000 SF Multi-Tenant Office/Lab Addition and Pavement Areas Colorado State University (CSU) – Engines and Energy Conservation Lab 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 Mr. MacMillan: Enclosed, herewith, are the results of the geotechnical subsurface exploration completed by Earth Engineering Consultants, Inc. (EEC) personnel for the proposed additions/site improvements for the existing Colorado State University’s Engines and Energy Conservation Laboratory (EECL) facility located at 430 North College Avenue in Fort Collins, Colorado. As we understand, this project involves the construction of an approximate 50,000 square foot, single to 3-story multi-tenant office/laboratory addition to the existing EECL building, along with associated pavement areas. The proposed building addition is currently planned with basement construction similar to the existing EECL facility. The on-site pavement areas are planned as composite hot mix asphalt (HMA) underlain by aggregate base course (ABC) pavement sections, with a designated area potentially utilizing permeable pavers. This study was completed in general accordance with our proposal dated March 30, 2011. The site is known to be a former landfill, with fill and landfill materials extending to a native sand and gravel strata. Due to the known presence of landfill debris and the possibility for asbestos containing materials (ACM) an environmental assessment was conducted concurrently with our geotechnical subsurface exploration by Walsh Environmental Engineers and Scientists (Walsh). As part of the environmental related concerns, the site is under a “Soil Characterization Management Plan” (SCMP), and a “soil-spotter” from Walsh was present during the geotechnical subsurface exploration drilling operations. In summary, the subsurface materials encountered in the three (3) geotechnical engineering borings consisted of approximately 17 to 18-feet of existing fill material/landfill debris overlying native sand, gravel and intermittent cobbles. Within a few of the split-spoon CDN#CDN #2214A-2627A-012 005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 2 samples obtained with the upper 14-feet, and periodic auger cuttings, slight evidence of landfill debris consisting of cinders, wood, ceramic tile, and copper wiring were noted; other material may be present and variations in depth may exist across the site. The native silty sand with gravel and intermittent cobbles extended to the bedrock formation below. The granular stratum was moist to saturated, and medium dense to dense to very dense with increased depths. The sandstone bedrock formation was encountered at approximate depths of 27 to 28-feet below existing site grades and extended to the depths explored, approximately 40 to 45-feet. Groundwater was encountered in each of the soil borings at approximate depths of 17 to 18-feet below site grades. Based on results of the field borings and laboratory testing, it is our opinion the proposed single to 3-story, with probable basement construction, steel framed building, could be supported on a conventional spread footing foundation system bearing on the native granular subsoils or on approved engineered fill material which extends to the native granular subsoils. No foundation should be founded within the existing landfill zone. An alternative foundation system, similar to that used for the adjacent Northside Aztlan Community Center to the south and the Discovery Museum building currently under construction to the west would be to support the proposed EECL addition on a screwpile foundation system extending into the underlying sandstone bedrock formation. Assuming the planned basement construction would generally conform to the existing building’s lower level floor slab elevation, as shown on the “Transverse Section – Figure No. 2 Diagram” in the Appendix of this report, the basement slab would be founded on either the native granular subsoils or on approved fill materials extended to the native zone as described herein. However within the pavement areas, due to the presence of unconsolidated/uncontrolled fill materials with miscellaneous landfill debris, we would suggest a minimum of 4-feet of approved engineered fill material be placed and compacted beneath all new pavement sections, with the understanding that some movement could still occur. Extreme care will be needed to evaluate the anticipated bearing materials to verify that footings are not supported on or immediately above zones of loose, consolidation prone lenses and/or with landfill debris. Footings, if utilized, should be placed on similar like materials to CDN#2214A-005 CDN#2214A-005 SUBSURFACE EXPLORATION REPORT PROPOSED 50,000 SF MULTI-TENNANT OFFICE/LAB ADDITION CSU – ENGINES AND ENERGY CONSERVATION LAB 430 NORTH COLLEGE AVENUE FORT COLLINS, COLORADO EEC PROJECT NO. 1112015 June 14, 2011 INTRODUCTION The subsurface exploration for the proposed additions/site improvements for the existing Colorado State University’s Engines and Energy Conservation Laboratory (EECL) facility located at 430 North College Avenue in Fort Collins, Colorado has been completed. Three (3) soil borings extending to depths of approximately 40 to 45-feet below present site grades were advanced within the planned building addition area to develop information on existing subsurface conditions. Individual boring logs and a diagram indicating the approximate boring locations relative to the proposed building addition and pavement improvement areas are included with this report. We understand this project involves the construction of an approximate 50,000 square foot, single to 3-story multi-tenant office/laboratory addition to the existing EECL building and associated on-site pavement improvement areas. The proposed building addition is currently planned with full-depth basement construction similar to the existing EECL facility. We anticipate maximum wall and column loads from the building addition will be on the order of 4 klf and 200 kips, respectively, along with moderate to heavy floor loading conditions. The on-site pavement improvements are currently planned as composite hot mix asphalt (HMA) underlain by aggregate base course (ABC), along with a designated area possibly utilizing permeable pavers. Minor grade changes are expected to develop final site grades. The purpose of this report is to describe the subsurface conditions encountered in the three (3) soil 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, Inc. (EEC) by pacing and estimating angles from identifiable site features. Those approximate boring locations are indicated on the attached boring location diagram. The locations CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 2 of the borings should be considerate accurate only to the degree implied by the methods used to make the field measurements. Due to the known presence of landfill debris and the possibility for asbestos containing materials (ACM), an environmental assessment was conducted concurrently with our geotechnical subsurface exploration by Walsh Environmental Engineers and Scientists (Walsh). As part of the environmental related concerns, the site is under a “Soil Characterization Management Plan” (SCMP), and a “soil-spotter” from Walsh was on-site during the geotechnical subsurface exploration drilling operations. The borings were performed using a truck-mounted, CME-75 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-1/4-inch nominal inside diameter continuous hollow stem augers and samples of the subsurface materials encountered were obtained using split-barrel sampling procedures in general accordance with ASTM Specifications D-1586. In the split barrel sampling procedure, a standard sampling spoon is 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 sampler is recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. All samples obtained in the field were sealed and returned to the laboratory for further examination, classification and testing. Moisture content tests were completed on each of the recovered samples. The unconfined strength of appropriate samples was estimated using a calibrated hand penetrometer. The quantity and plasticity of the fines in the subgrade were determined by washed sieve analysis and Atterberg limits tests on selected samples. Water soluble sulfates (SO4) tests were completed on selected samples to evaluate the risk of sulfate attack of the subsurface materials on Portland cement concrete. Results of the outlined tests are indicated on the attached boring logs and summary sheets. Environmental analytical testing services were performed by Walsh and are beyond the scope of services conducted by EEC. As part of the testing program, all samples were examined in the laboratory by an engineer and classified in 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 CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 3 system is included with this report. Classification of the bedrock was based on visual and tactual observation of disturbed samples and auger cuttings. Coring and/or petrographic analysis may reveal other rock types. SITE AND SUBSURFACE CONDITIONS The proposed building addition will be constructed on the south side of the existing EECL building within a grass landscaped area and existing asphalt paved portion of the property. The area for the proposed addition is relative flat, with positive drainage generally in the south to east directions. Photographs of the site were taken during the subsurface exploration and are included in the Appendix of this report. An EEC field engineer was on site during the drilling operations to evaluate the subsurface conditions encountered and direct the drilling activities. Field logs prepared by EEC’s site personnel were based on visual and tactual observation of auger cuttings and disturbed samples. A “soil- spotter” from Walsh was also on-site during the subsurface exploration activities as required per the site-specific SCMP. The boring logs included with this report may contain modifications to the field logs based on results of laboratory testing and engineering evaluation. Based on results of the field boring and laboratory testing, subsurface conditions can be generalized as follows. At boring location B-1, an approximate 6 to 8-inch layer of existing topsoil/grass landscape surficial layer was encountered. At the surface of borings B-2 and B-3, an existing pavement section consisting of approximate 2 to 2-1/2-inches of asphaltic concrete underlain by approximately 6- inches of existing aggregate base course was encountered. In summary, the subsurface materials encountered beneath the surficial layer in each of the three (3) geotechnical engineering borings consisted of approximately 17 to 18-feet of existing fill material/landfill debris, which extended to the native sand, gravel and intermittent cobble zone below. Within a few of the split-spoon samples obtained with the upper 9 and 14-foot samples and periodic auger cuttings, slight evidence of landfill debris consisting of cinders, wood, ceramic tile, and copper wiring were noted; other materials may be present and variations in depth may exist across the site. Underlying the fill/landfill materials was the native silty sand with gravel and intermittent cobbles which extended to the bedrock formation below. The granular stratum was moist to saturated and medium dense to very dense with CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 4 increased depths. The sandstone bedrock formation was encountered at approximate depths of 27 to 28-feet below existing site grades and extended to the depths explored, approximately 40 to 45-feet. Well-cemented sandstone bedrock lenses were encountered at increased depths, as evident by the Standard Penetration Test (SPT) results presented on our boring logs presented in the Appendix of this report. The underlying bedrock formation with intermittent well-cemented sandstone lenses, SPT results ranging between 50 blows per ½ -inch to 50-blows per 3-inches at increased depths. To penetrate the well-cemented sandstone lenses, specialized equipment will be required. 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. WATER LEVEL OBSERVATIONS Groundwater was encountered in each of the soil borings at approximate depths of 17 to 18-feet below site grades. As requested, due to the environmental concerns, the borings were backfilled with bentonite upon completion of the drilling operation; therefore stabilized/subsequent groundwater 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. In addition, zones of perched and/or trapped may be encountered at times throughout the year in more permeable areas within the subgrade materials. The location and amount of perched water can also vary over time depending on variations in hydrologic conditions and other conditions not apparent at the time of this report. ANALYSIS AND RECOMMENDATIONS General Considerations and Discussion of Fill/Landfill Materials As shown on the enclosed boring logs, the area for the proposed addition and site improvements is generally underlain by approximately 18-feet of fill material with interbedded landfill debris. Walsh performed a Phase II Environmental Site Assessment for the property and has evaluated the landfill CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 5 material accordingly. Due to the unconsolidated and uncontrolled characteristics of the fill material, in conjunction with the potential environmental related concerns, the in-situ fill/landfill material should not be used for support of foundations and/or floor slabs. The consistency and composite of the fill/landfill material is unknown, therefore an estimation of short term and /or long-term settlement cannot be determined or a determination of the material’s lateral earth pressures or stability. The lateral earth pressures presented herein are for approved imported cohesive and/or non-cohesive materials placed and compacted in general accordance with the earthwork recommendations in this report. As discussed in the Site Preparation section of this report, a “bridging layer” over the landfill material with a suitable/approved imported material within the pavement areas may be considered, depending upon the acceptable risk of long-term movement of the pavements. The recommendations contained in this report assume that imported/approved fill material will be required, and will be placed according to the recommendations provided herein. If there are any significant deviations from the assumptions concerning fill placement when the final site plan is developed, the conclusions and recommendations of this report should be reviewed and confirmed/modified as necessary to reflect the final planned site configuration. General Considerations Precautions will be required in the design and construction of the building addition and new pavements to address the existing fill material with intermittent landfill debris, the removal/excavation of cobbles at increased depths, penetration of the underlying well cemented sandstone bedrock lenses, and shoring/protection of the existing building and property amenities during excavation for the basement level of the addition. Depending upon the depth of excavation, (i.e., if lower level construction is being planned for), consideration should be given to installing an underdrain/underslab drainage system to intercept or control groundwater from impacting the lowest opening. Removal of large sized cobbles during excavation procedures may be necessary to reduce the potential for point loading conditions developing on foundation and floor slabs. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 6 It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. However, if excavations penetrating the well-cemented sandstone bedrock are required, the use of specialized heavy-duty equipment such as a rock hammer or core barrel to achieve final design elevations may be necessary. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. With the location of the proposed 3-story building and the close proximity of adjacent railroad tracks and the existing building, shoring mechanisms to protect these features may be required during excavation stages. Depending upon the depth of lower level construction, a shoring plan will be necessary to protect the adjacent sidewall slopes. The project design team should use the subsurface information provided herein to properly design a mechanism for shoring protection. EEC is available to provide supplemental design criteria or details such as but not limited to secant piles or piers, soldier piers, or a tie-back/bracing concept. Site Preparation Although final site grades were not available at the time of this report, based on our understanding of the proposed development, we expect about 1 to 3-feet of fill material may be necessary to achieve design grades, (i.e., assuming the new addition will generally conform to the existing building’s finished first floor elevation). Pending the results of the Walsh Phase II ESA, within the building footprint, and applying the appropriate OSHA set-back/slope criteria, all of the existing fill material with interbedded landfill debris, should be removed and either stockpiled for reuse as fill material or hauled off-site. The majority of the fill material generally consisted of clayey sand with gravel and/or sandy lean clay with gravel and intermittent cobbles, with various “pockets” of landfill debris. If portions of the fill material is consideration acceptable from an environmental viewpoint, the over-excavated material void of landfill debris, could be stockpiled for reuse as engineered fill material. After stripping, over-excavating and completing all cuts, and prior to placement of any fill material or site improvements, we recommend the exposed subsoils below, where practical within the pavement areas, be scarified to a minimum depth of 12-inches, adjusted in moisture content to within 0 to (+) 4% of modified Proctor optimum moisture content, and compacted to at least 90% of CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 7 the material's modified Proctor maximum dry density as determined in accordance with ASTM Specification D-1557. Due to the unreliable characteristics of portions of the existing site subsoils within the pavement areas, ground stabilization mechanisms may be necessary to create a working platform for construction equipment. Placement of a granular material, such as a 3-inch minus recycled concrete or equivalent, may be necessary as a subgrade enhancement layer embedded into the underlying “left-in-place” existing fill material zones, prior to placement of any additional fill material or operating heavy earth-moving equipment. Supplemental recommendations can be provided upon request. Fill soils required for developing the building, pavement and site subgrades, after the initial subgrade zone, (i.e., the layer beneath any over-excavation requirements) has been stabilized, where applicable, should consist of approved, low-volume-change materials, which are free from organic matter and landfill and/or construction debris. We recommend structural fill materials be placed and compacted within the building footprint and consist of essentially granular soils with less than 20% material passing the No. 200 sieve. We recommend fill materials be placed in loose lifts not to exceed 9 inches thick and adjusted in moisture content, generally +/- 2% of optimum moisture content, and compacted to at least 95% of the materials maximum dry density as determined in accordance with ASTM Specification D-1557, the modified Proctor procedure. Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade materials. Positive drainage should be developed away from the structure to avoid wetting of subgrade materials. Subgrade materials becoming wet subsequent to construction of the site structure can result in unacceptable performance. In areas where excavations will extend below existing groundwater table, placement of cleaner granular fill material would be desirable, (i.e. material having less than 10 percent passing the No. 200 sieve relatively consistent with the native granular subsoils). Those materials should be placed in lifts and compacted to at least 70% relative density, ASTM Specification D4253 and D4254. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 8 Foundation Systems – General Considerations The site appears useable 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 for the proposed 50,000 SF, 3-story structure having full-depth basement construction:  Screwpiles extending into the underlying bedrock formation, and  Conventional type spread footings bearing on the native, underlying granular strata, or on engineered fill material extended to the native sand and gravel layer. Foundation Systems–Screwpiles (comparable to drilled piers) A deep foundation system to consider, which was the preferred approach for the Northside Aztlan Community Center project to the south, and the Discovery Museum project currently being constructed to the west, would be to support the proposed EECL building addition on screwpiles. There are several benefits for using a screwpile design concept versus a drilled pier in certain situations, especially in cases similar to this site, with the presence of unconsolidated/uncontrolled fill material, relatively shallow groundwater, and where bedrock is encountered within approximately 30-feet from existing site grades. A screwpile can be installed in less time than a drilled pier and there is no need for concrete, a pump truck, or additional reinforcement. Casing is not necessary and a screwpile can also be loaded up to approximately 350 to 500 kips, or a series of screwpiles can be installed to achieve a greater concentrated loading arrangement. The project design team could contact a reputable screwpile contractor to provide additional information and design services for the project. The screwpile contractor should also provide a site-specific load test to determine the achievable torque necessary to support the anticipated loads imposed by the proposed additions. The screwpile contractor working in conjunction with the project’s structural engineer, should be capable of designing a screwpile foundation system to accommodate the necessary loads for the project based on the structural engineer's load design calculations as well as a pile cap/foundation wall system. The screwpiles may vary with depth and generally follow the bedrock contours. The screwpiles should extend into the underlying bedrock formation sufficiently to achieve the design torque to CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 9 support the anticipated loading parameters. A screwpile is installed to a design torque and not necessarily a required depth of penetration into the bedrock. As long as the required torque is achieved the screwpile install typically is then terminated. In general, depending upon the design loads as well as the design torque, a screwpile may only extend a few feet into the bedrock formation. The screwpile contractor and/or associates should be capable of designing the screwpile system with the necessary pipe diameter, wall thickness, and helix flight configuration to accommodate the project. EEC can provide supplemental on-site corrosivity characteristics of the underlying subsurface soils upon request. Based upon review of the soil, bedrock, and groundwater conditions at the site, it is our opinion a screwpile foundation system could be considered as a foundation system for this site. However, an experienced screwpile contractor should be consulted to review the boring logs provided in this site- specific geotechnical report. Groundwater, intermittent cobbles, and variable depths to the cemented to well-cemented sandstone bedrock encountered at the site could result in pile installation difficulties. At a minimum, we recommend that test piles/load test procedures be conducted to determine the appropriate design parameters for the site, (i.e. tested for axial and lateral capacity prior to installing production piles). If lateral load testing cannot be performed, a sufficient number of battered piles should be installed to resist all lateral loading imposed. The actual design of the piles including the pile capacity, spacing, helix diameter(s), shaft length, bracket attachment and configuration, and shaft diameter should be performed by an experienced screwpile contractor or structural engineer. As previously outlined, due to the subsurface conditions and variable depth to bedrock, an experienced screwpile contractor should review the data to assess whether heavy-duty equipment or pre-drilling will be required to achieve the minimum length and capacity. Screw piles should be considered to work in-group action if the horizontal spacing is less than 3 pile diameters. A minimum practical horizontal spacing between piles of at least 3 diameters should be maintained, and adjacent piles should bear at the same elevation. The capacity of individual piles must be reduced when considering the effects of group action. Capacity reduction is a function of pile spacing and the number of piles within a group. If group action analyses are necessary, capacity reduction factors can be provided for the analyses. Based on our understanding, installation of CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 10 screwpiles on the adjacent projects described herein did not appear to pose much difficulty during the initial construction phase; however variations may exist on the EECL site. Foundations – Conventional Type Spread Footings Based on results of field borings and laboratory testing as outlined in this report, it is our opinion the proposed building addition could be supported on conventional type spread footing foundations bearing on the native granular stratum encountered at an approximate depths of 18-feet below site grades, or on a zone of engineered fill material extending to the native granular subsoils. In no case should any foundation system be placed on the existing on-site fill material. Footings bearing on approved native granular subsoils or on engineered fill material extended to the granular strata could be designed for a maximum net allowable bearing pressure of 3,000 psf. Based on our review of the existing “Transverse Section Layout – Figure 2” diagram included in the Appendix of this report, it appears the existing building’s foundation system consists of a conventional type spread foundation bearing on the native granular subsoils. If fill material is required to achieve foundation bearing elevations, the engineered fill material should consist of imported structural fill placed in uniform lifts; properly moisture conditioned, and mechanically compacted to at least 95% of modified Proctor density (ASTM D1557). The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Overexcavation for placement of the structural fill should extend to the native granular subsoils, and should extend at least eight (8) inches beyond the edges of the foundations for each 12 inches of structural fill placed beneath the footing. We estimate the long-term settlement of footing foundations supported on suitable strength native granular subsoils or engineered fill material, and designed and constructed as outlined above would be about 1-inch or less. Differential settlement should be expected between the addition and the existing structure. The differential settlement could approach the expected total settlement of the proposed addition. Steps should be taken to accommodate the anticipated differential settlement between the existing building and the addition. A minimum dead load pressure would not be required in the low swell potential subsoils as described herein. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 11 Exterior footings and foundations in unheated areas must be protected from frost action. The normal depth of frost protection in this location is a minimum depth of 30-inches. Continuous wall footings generally have a width of at least 12-inches. Isolated column pads generally require dimensions of at least 24-inches by 24-inches. Based upon the structural loading conditions provided, larger footing sizes may be needed to accommodate actual foundation load and design requirements. Footings should be proportioned to reduce differential foundation movement. Proportioning on the basis of equal total settlement is recommended; however, proportioning to relative constant dead- load pressure will also reduce differential settlement between adjacent footings. Total settlement resulting from the assumed structural loads is estimated to be on the order of 1 inch or less. Differential settlement should be on the order of 1/2 to 3/4 of the estimated total settlement. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction. Care should be taken during construction to see that the footing foundations are supported on suitable strength native subsoils or approved fill material. In areas immediately adjacent to the existing structure, previously placed backfill materials may be encountered beneath the foundation bearing levels. Extra care should be taken in evaluating the in-place soils in these areas as the backfill materials are commonly not placed for future support of foundations. If unacceptable materials are encountered at the time of construction, it may be necessary to extend the footing foundations to bear below the unacceptable materials or removal and replacement of a portion or all of the unacceptable materials may be required. Those conditions can best be evaluated in open excavations at the time of construction. No unusual problems, other than any potential environmentally related concerns that may be presented by Walsh, are anticipated in completing the excavation required for construction of the footing foundations. Due to the presence of groundwater at approximate depths of 17 to 18-feet below site, and depending upon final excavation grades, temporary dewatering may be necessary. Care should be taken during construction to avoid disturbing the foundation bearing materials. 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 prior to placement of foundation concrete. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 12 Seismic The site soil conditions consist of approximately 27 to 28-feet of existing fill material and overburden granular subsoils overlying cemented to well-cemented sandstone bedrock. For those site conditions, the 2006 International Building Code indicates a Seismic Site Classification of D. Lateral Earth Pressures As we understand the current plan is to construct a full-depth basement with the new EECL building. Therefore portions of the building will be subjected to unbalanced lateral earth pressures. Passive lateral earth pressures may help resist the driving forces for retaining wall or other similar site structures. The values presented herein are for approved imported material placed and compacted adjacent to the EECL basement foundation walls. If, depending upon design considerations, lateral earth pressures are required for the existing on-site subsoils, additional testing would be required. 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. 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 a 30 degrees or low volume change cohesive soils. For the at-rest and active earth pressures, slopes down and away from the structure would result in reduced driving forces with slopes up and away from the structures resulting in greater forces on the walls. The passive resistance would be reduced with slopes away from the wall. The top 30-inches of soil on the passive resistance side of walls could be used as a surcharge load; however, 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. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 13 Soil Type – ONLY FOR APPROVED MATERIALS Low Plasticity Cohesive – Approved Import Material Medium Dense Granular – On- site or Approved Imported Fill Wet Unit Weight 115 135 Saturated Unit Weight 135 140 Friction Angle () – (assumed) 15° 30° Active Pressure Coefficient 0.59 0.33 At-rest Pressure Coefficient 0.74 0.50 Passive Pressure Coefficient 1.70 3.00 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 into the system. Where necessary, appropriate hydrostatic load values should be used for design. Basement Construction Based on our understanding the initial building design concept, a full-depth basement is currently planned. Groundwater was encountered within the three (3) geotechnical soil borings at approximate depths of 17 to 18-feet below existing site grades; however variations may exist across the site. Full- depth basement construction could be considered for the site provided a permanent drainage system is installed. Surface water infiltration and/or groundwater fluctuations may impact the underlying foundation and/or floor subgrade materials. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 14 Any below grade level construction for the site should be placed a minimum of 4-feet above the maximum anticipate rise in groundwater. If this cannot be achieved an underdrain system should be installed to reduce the potential for hydrostatic loads to develop as well as to control elevated groundwater levels on below grade walls and to intercept infiltration of surface water into below grade areas. When design grades are more established, we should be consulted to further evaluate the necessity of an underdrain system for the site and provide supplemental recommendations in addition to those presented herein. Floor Slab Subgrades All existing vegetation/topsoil and/or existing pavement and associated fill materials with intermittent landfill debris should be removed from beneath the new building floor slab area(s). Based on our review of the “Transverse Section Layout – Figure 2” diagram included in the Appendix of this report, it appears the existing building may have a structural floor system isolated from the underlying subsurface materials. It also appears the existing foundation system and floor slab is positioned on native subsoils below the extent of the landfill zone. Depending upon the results developed from Walsh’s Phase II ESA study, consideration could be given to utilizing a similar type structural floor system for the new building. Depending upon the final design grade for the lower/basement level floor slab and the constructability of either a conventional slab-on-grade concept or a structural floor method, placement of an approved imported structural fill material may be necessary to achieve final basement level subgrade elevations. If a slab-on-grade concept is utilized, and elevations from the native zone are required to achieve final grade, imported structural fill material should be placed and compacted to at least 95% of the material’s modified Proctor density, (ASTM D1557), as described in the Site Preparation” section of this report. Soft or loose in-place fill/backfill associated with prior building or utility construction and any wet and softened or dry and desiccated soils should be removed from the floor areas. Fill materials required to develop the floor slab subgrades should consist of approved, low-volume change materials which are free from organic matter and debris. We recommend structural fill materials be placed and compacted within the building footprint and consist of essentially granular CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 15 soils with less than 20% material passing the No. 200 sieve. Fill materials beneath the floor slabs areas should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted to at least 95% of the material's modified Proctor maximum dry density (ASTM D1557). After preparation of the subgrades, care should be taken to avoid disturbing the subgrade materials. Materials which are loosened or disturbed by the construction activities will require removal and replacement or reworking in place prior to placement of the overlying floor slabs. Positive drainage should be developed away from the proposed building addition to avoid wetting the subgrade or bearing materials. Subgrade or bearing materials allowed to become wetted subsequent to construction can result in unacceptable performance of the improvements. Pavement Subgrades Within the pavement improvement areas, all existing vegetation/topsoil and/or existing pavement and associated fill materials with intermittent landfill debris, should be removed to a minimum depth of 4-feet below existing site grades. Depending upon the results of the Walsh environmental assessment study and the areas/amount of existing fill material to remain, along with the acceptable amount of potential long-term movement within the on-site pavement improvement areas we suggest placing and compacting a “bridging layer” over the existing fill material. The suggested “bridge- layer” thickness would depend upon several factors, which can be further discussed when the design is further along. At a minimum, we would suggest the bridge layer consist of at least 4-feet of approved imported structural fill material placed and compacted to at least 95% of the material’s modified Proctor density, (ASTM D1557), as described in the Site Preparation” section of this report. For pavement near the addition, backfill against the basement walls my account for structural fill below at least a portion of those pavements. Fill materials required to develop the pavement subgrades should consist of approved, low-volume change materials which are free from organic matter and debris. We recommend structural fill materials be placed and compacted within the building footprint and consist of essentially granular soils with less than 20% material passing the No. 200 sieve. Fill materials beneath any pavement CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 16 improvement areas should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content, and compacted to at least 95% of the material's modified Proctor maximum dry density. After preparation of the subgrades, care should be taken to avoid disturbing the subgrade materials. Materials which are loosened or disturbed by the construction activities will require removal and replacement or reworking in place prior to placement of the overlying pavement sections. Pavement Design Sections We expect the site pavements will include areas designated for automobile traffic and areas for possible heavy-duty drive lanes. Heavy-duty areas we have assumed an equivalent daily load axle (EDLA) rating of 25 and automobile areas an EDLA of 10. Proofrolling and recompacting the subgrade is recommended immediately prior to placement of the aggregate road base section. Soft or weak areas delineated by the proofrolling operations should be undercut or stabilized in-place to achieve the appropriate subgrade support. Based on the subsurface conditions encountered at the site, we would assume the approved imported fill material would generally consist of a CDOT Class 7 aggregate base course type material having a minimum R-Value equivalency of 25. Subgrade stabilization to mitigate for potentially compressible conditions and/or consolidation prone conditions should be over-excavated and/or “cut to grade” to accommodate a minimum of 4-feet of non-expansive granular soils to be placed and compacted beneath the pavement section as previously described. Depending upon the severity of potential movement with the on-site existing subsurface conditions, increasing the over-excavation and replacement depth could be considered. A field determination may be required at the time of construction. Placement of imported structural fill material as described herein should provide for an acceptable subgrade support layer but will not address for long-term settlement of the unknown characteristics of the existing fill material at increased depths. The only way to minimize the amount of future movement within the pavement areas would to be removed the entire fill material with intermittent landfill debris beneath the entire pavement improvement areas. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 17 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 long-term settlement characteristics of the existing fill material with intermittent landfill debris susceptible to consolidation. Thus, the pavement may be adequate from a structural standpoint, yet still experience cracking and deformation due to related movement of the underlying subsoils. Recommended pavement sections are provided below in TABLE I. The hot mix asphalt (HMA) pavement should be grading S (75) or SX (75) with PG 58-28 oil. The aggregate base should be Class 5 or Class 6 base. Portland cement concrete should be a pavement design mix with a minimum 28-day compressive strength of 4,000 psi and should be air entrained. HMA pavements may show rutting and distress in truck loading or turning areas. Concrete pavements should be considered in those areas. TABLE I – RECOMMENDED PAVEMENT SECTIONS Automobile Parking Heavy Duty Areas EDLA ESAL’s – Based on 20-Year Design Life Reliability Resilient Modulus – Assume R-Value = 25 PSI Loss –(Initial = 4.5, Terminal = 2.5) 10 73,000 75% 5816 2.0 25 182,500 85% 5816 2.0 Design Structure Number 2.21 2.71 Composite: Alternative A Hot Mix Asphalt (HMA) Aggregate Base Course (ABC) – CDOT Class 5 or 6 Design Structure Number 4" 6" (2.42) 4-1/2" 7" (2.75) PCC (Non-reinforced) 5” 6″ The recommended pavement sections are minimums and 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 within 24-hours of concrete placement. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 18 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. Depending upon the final decision as to the extent and/or limits for removal of the existing fill material, EEC can provide additional preventive maintenance suggestions and/or recommendations upon request. 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. 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 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 CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 19 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. The water soluble sulfate (SO4) testing of the site overburden materials indicated sulfate contents of less than 10 ppm, while the underlying bedrock revealed sulfate contents on the order of approximately 250 ppm. Sulfate content less than 150 ppm (0.1 percent) is considered negligible risk of sulfate attack on Portland cement concrete, whereas sulfate contents between 150 and 1,500 ppm indicate a moderate sulfate exposure, requiring a Type II cement. For the overburden soils, these results indicate that ASTM Type I Portland cement is suitable for all concrete; however, if there is no, or minimal cost differential, use of ASTM Type II Portland cement is recommended for additional sulfate resistance of construction concrete. For imported fill material planned for use on-site, additional laboratory testing should be performed to evaluate the material’s water soluble sulfate characteristics to determine the appropriate type of cement. Foundation concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. Excavations into the on-site soils may encounter a variety of conditions, especially within the delineated landfill footprint portion on the site. Excavations extending into the on-site underlying fill zone and native granular strata may encounter loose and caving conditions. 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 and taking into account the site subsurface conditions as described herein. 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. All underground piping within or near the proposed structure should be designed with flexible couplings, so minor deviations in alignment do not result in breakage or distress. Depending upon the amount of removal of the existing fill material with intermittent landfill debris, consideration should be given to providing flexible connections with all new utility alignments to accommodate for potentially shifting underlying subsoils. Utility knockouts in foundation walls should be oversized to accommodate differential movements. CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 20 All piping should be adequately bedded for proper load distribution. It is suggested that clean, graded gravel compacted to at least 70 percent of Relative Density ASTM D4253 and D4254 be used as bedding. Where utilities are excavated below groundwater, temporary dewatering will be required during excavation, pipe placement and backfilling operations for proper construction. Utility trenches should be excavated on safe and stable slopes in accordance with OSHA regulations as discussed above. Backfill should consist of the on-site soils or approved imported materials. The pipe backfill should be compacted to a minimum of 90% of modified Proctor density ASTM D698,outside of the building envelop and to at least 95% of modified Proctor density within the building footprint, consistent with the floor slab and backfill recommendations as previously provided. 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 further exploration or 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 that 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 and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use for representatives with CSURF and/or appropriate assignee, 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 CDN#2214A-005 Earth Engineering Consultants, Inc. CSU’s EECL – 430 North College Avenue Fort Collins, Colorado EEC Project No. 1112015 June 14, 2011 Page 21 shall not be considered valid unless the changes are reviewed and the conclusions of this report modified or verified in writing by the geotechnical engineer. CDN#2214A-005 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. HARDNESS AND DEGREE OF CEMENTATION: CDN#2214A-005 CDN#2214A-005 CDN #2627A-012 CDN#2214A-005 CDN #2627A-012 COLORADO STATE UNIVERSITY – ENGINES & ENERGY CONSERVATION LAB FORT COLLINS, COLORADO EEC PROJECT NO. 1112015 JUNE 2011 PHOTO #1 PHOTO #2 CDN#2214A-005 COLORADO STATE UNIVERSITY – ENGINES & ENERGY CONSERVATION LAB FORT COLLINS, COLORADO EEC PROJECT NO. 1112015 JUNE 2011 PHOTO #3 PHOTO #4 CDN#2214A-005 DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF SPARSE VEGETATION - GRASS LANSCAPED AREA _ _ 1 FILL MATERIAL: Sandy Lean Clay/Clayey Sand w/ Gravel _ _ Miscellaneous LANDFILL DEBRIS 2 loose unconsolidated material _ _ evidence of wood, ceramic tiles, copper, cinders, and 3 miscellaneous landfill debris, minimal evidence _ _ of asbestos containing materials (ACM) 4 drilling operations monitored by WALSH _ _ Environmental Consultants as "soil-spotters" 5 _ _ 6 Note: due to presence of known landfill debris, upper level _ _ soil samples were not obtained. EEC began sampling at an 7 approximate depth of 9-feet below site grade to assist _ _ in delineating depth of landfill debris 8 _ _ 9 _ _ 1 *Evidence of FILL MATERIAL at 9-feet SS 10 0 -- 20.3 _ _ 1 11 _ _ 12 _ _ 13 _ _ 14 _ _ 2 *Evidence of FILL MATERIAL at 14-feet 15 3 -- 55.3 _ _ 4 16 _ _ 17 _ _ 18 _ _ SILTY SAND with GRAVEL and COBBLES 19 tan, gray, rust, moist to saturated, medium dense _ _ 13 to dense granular strata SS 20 17 -- 7.3 _ _ 22 21 _ _ 22 _ _ 23 _ _ 24 _ _ 50 SS 25 17 -- 11.4 NL NP 4.1 Continued on Sheet 2 of 2 _ _ 50 Earth Engineering Consultants 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Continued from Sheet 1 of 2 26 SILTY SAND with GRAVEL and COBBLES _ _ 27 _ _ SANDSTONE BEDROCK 28 weathered tan, olive, gray with depth _ _ cemented to well cemented with increased depth 29 _ _ 30 50/2-1/2" 9000 20.4 _ _ 31 _ _ 32 _ _ 33 _ _ 34 SS _ _ 50/1" -- 1.1 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 SS _ _ 50/1/2" -- 19.3 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 SS _ _ 50/1/2" -- 22.4 BOTTOM OF BORING DEPTH 44.1' 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF _ _ AGGREGATE BASE COURSE - Existing approx. 6-inches 1 _ _ FILL MATERIAL: Sandy Lean Clay/Clayey Sand w/ Gravel 2 Miscellaneous LANDFILL DEBRIS _ _ loose unconsolidated material 3 evidence of wood, ceramic tiles, copper, cinders, and _ _ miscellaneous landfill debris, minimal evidence 4 of asbestos containing materials (ACM) _ _ drilling operations monitored by WALSH 5 Environmental Consultants as "soil-spotters" _ _ 6 _ _ Note: due to presence of known landfill debris, upper level 7 soil samples were not obtained. EEC began sampling at an _ _ approximate depth of 9-feet below site grade to assist 8 in delineating depth of landfill debris _ _ 9 _ _ 1 *Evidence of FILL MATERIAL at 9-feet SS 10 0 -- 58.6 _ _ 1 11 _ _ 12 _ _ 13 _ _ 14 _ _ 1 *Evidence of FILL MATERIAL at 14-feet 15 2 -- 62.5 _ _ 1 16 _ _ 17 _ _ SILTY SAND with GRAVEL and COBBLES 18 tan, gray, rust, moist to saturated, medium dense _ _ to dense granular strata 19 _ _ 7 SS 20 19 -- 9.1 NL NP 5.7 _ _ 27 21 _ _ 22 _ _ 23 _ _ 24 _ _ 19 SS 25 27 9000+ 15.7 Continued on Sheet 2 of 2 _ _ 29 Earth Engineering Consultants COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Continued from Sheet 1 of 2 26 SILTY SAND with GRAVEL and COBBLES _ _ 27 _ _ SANDSTONE BEDROCK 28 weathered tan, olive, gray with depth _ _ cemented to well cemented with increased depth 29 _ _ 30 50/2" -- _ _ 31 _ _ 32 _ _ 33 _ _ 34 SS _ _ 50/1-1/2" 6000 16.6 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 SS _ _ 50/3" 9000+ 22.5 BOTTOM OF BORING DEPTH 39.3' 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF _ _ AGGREGATE BASE COURSE - Existing approx. 6-inches 1 _ _ FILL MATERIAL: Sandy Lean Clay/Clayey Sand w/ Gravel 2 Miscellaneous LANDFILL DEBRIS _ _ loose unconsolidated material 3 evidence of wood, ceramic tiles, copper, cinders, and _ _ miscellaneous landfill debris, minimal evidence 4 of asbestos containing materials (ACM) _ _ drilling operations monitored by WALSH 5 Environmental Consultants as "soil-spotters" _ _ 6 _ _ Note: due to presence of known landfill debris, upper level 7 soil samples were not obtained. EEC began sampling at an _ _ approximate depth of 9-feet below site grade to assist 8 in delineating depth of landfill debris _ _ 9 _ _ 1 *Evidence of FILL MATERIAL at 9-feet SS 10 2 -- 29.7 _ _ 2 11 _ _ 12 _ _ 13 _ _ 14 _ _ 1 15 2 -- _ _ 3 16 _ _ 17 _ _ 18 _ _ SILTY SAND with GRAVEL and COBBLES 19 tan, gray, rust, moist to saturated, medium dense _ _ to dense granular strata 20 50/9" -- 10.2 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 50/10" 12.6 NL NP 8.7 Continued on Sheet 2 of 2 _ _ Earth Engineering Consultants COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) DATE: RIG TYPE: CME 75 FOREMAN: DAR AUGER TYPE: 4-1/4" Inside Dia. HSA SPT HAMMER: MANUAL SOIL DESCRIPTION D N QU MC DD -200 TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF Continued from Sheet 1 of 2 26 SILTY SAND with GRAVEL and COBBLES _ _ 27 _ _ SANDSTONE BEDROCK 28 weathered tan, olive, gray with depth _ _ cemented to well cemented with increased depth 29 _ _ 30 50/3/4" -- 20.5 _ _ 31 _ _ 32 _ _ 33 _ _ 34 SS _ _ 50/1" NR -- 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 SS _ _ 50/1-1/2" 4000 18.7 BOTTOM OF BORING DEPTH 39.2' 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO Project: Colorado State University (CSU) - Engines and Energy Conservation Lab (EECL) Location: Fort Collins, Colorado Project No: 1112015 Sample Desc.: B-1, S-4, at 24' Date: June 2011 EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS 100 18 13 100 97 Sieve Size 2 1/2" 2" Percent Passing 100 100 No. 8 1 1/2" 1" 3/4" 89 86 75 62 43 1/2" 3/8" 6 4.1 25 No. 4 No. 30 No. 40 No. 50 No. 100 No. 200 No. 16 CDN#2214A-005 Project: Colorado State University (CSU) - Engines and Energy Conservation Lab (EECL) Location: Fort Collins, Colorado Project No: 1112015 Sample Desc.: B-2, S-2, at 19' Date: June 2011 EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS 100 19 14 87 78 Sieve Size 2 1/2" 2" Percent Passing 100 100 No. 8 1 1/2" 1" 3/4" 69 63 53 44 35 1/2" 3/8" 9 5.7 25 No. 4 No. 30 No. 40 No. 50 No. 100 No. 200 No. 16 CDN#2214A-005 Project: Colorado State University (CSU) - Engines and Energy Conservation Lab (EECL) Location: Fort Collins, Colorado Project No: 1112015 Sample Desc.: B-3, S-3, at 24' Date: June 2011 EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS 100 30 25 90 87 Sieve Size 2 1/2" 2" Percent Passing 100 100 No. 8 1 1/2" 1" 3/4" 82 78 73 66 54 1/2" 3/8" 15 8.7 37 No. 4 No. 30 No. 40 No. 50 No. 100 No. 200 No. 16 CDN#2214A-005 PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-3 SHEET 2 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 18.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported APPROX. SURFACE ELEV Not Reported 24 HOUR Backfilled A-LIMITS SWELL SS *Interbedded well cemented lenses with increased depths CDN#2214A-005 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-3 SHEET 1 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 18.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported APPROX. SURFACE ELEV Not Reported 24 HOUR Backfilled A-LIMITS SWELL SS ASPHALT PAVEMENT - Existing HMA approx. 2-inches SS *Intermittent 3-inch and larger sized cobbles with increased depths *Evidence of NATIVE CLAYEY SAND zone at 14- feet; however copper wiring was encountered in split-spoon sample at 19-feet. SS CDN#2214A-005 PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-2 SHEET 2 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 17.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported Backfilled A-LIMITS SWELL APPROX. SURFACE ELEV SS *Interbedded well cemented lenses with increased depths Not Reported 24 HOUR CDN#2214A-005 430 NORTH COLLEGE AVENUE - FORT COLLINS, COLORADO PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-2 SHEET 1 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 17.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported A-LIMITS SWELL APPROX. SURFACE ELEV Not Reported 24 HOUR Backfilled SS *Intermittent 3-inch and larger sized cobbles with increased depths ASPHALT PAVEMENT - Existing HMA approx. 2-inches CDN#2214A-005 PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-1 SHEET 2 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 18.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported APPROX. SURFACE ELEV Not Reported SS *Interbedded well cemented lenses with increased depths 24 HOUR Backfilled A-LIMITS SWELL CDN#2214A-005 COLORADO STATE UNIVERSITY (CSU) - ENGINES AND ENERGY CONSERVATION LAB (EECL) PROJECT NO: 1112015 JUNE 2011 LOG OF BORING B-1 SHEET 1 OF 2 WATER DEPTH START DATE 6/2/2011 WHILE DRILLING 18.0' FINISH DATE 6/2/2011 AFTER DRILLING Not Reported APPROX. SURFACE ELEV Not Reported 24 HOUR Backfilled SS *Intermittent 3-inch and larger sized cobbles with increased depths A-LIMITS SWELL CDN#2214A-005 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 CDN#2214A-005