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HomeMy WebLinkAboutPATEROS CREEK - PDP - PDP130011 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORTPRELIMINARY SUBSURFACE EXPLORATION REPORT 912 WOOD STREET – PROPOSED RESIDENTIAL DEVELOPMENT FORMER BENDER MOBILE HOME PARK NORTH OF CITY OF FORT COLLINS UTILITIES AND SOUTH OF THE CACHE LA POUDRE RIVER FORT COLLINS, COLORADO EEC PROJECT NO. 1112069 Prepared for: Bellisimo, Inc. 3702 Manhattan Avenue, Suite 201 Fort Collins, Colorado 80526 Attn: Mr. Gino Campana (gcampana@bellisimo-inc.com) Prepared by: Earth Engineering Consultants, Inc. 4396 Greenfield Drive Windsor, Colorado 80550 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 www.earth-engineering.com November 17, 2011 Bellisimo, Inc. 3702 Manhattan Ave Suite 201 Fort Collins, Colorado 80526 Attn: Mr. Gino Campana (gcampana@bellisimo-inc.com) Re: Preliminary Subsurface Exploration Report 912 Wood Street – Proposed Residential Development Former Bender Mobile Home Park, North of City of Fort Collins Utilities and South of the Cache La Poudre River Fort Collins, Colorado EEC Project No. 1112069 Mr. Campana: Enclosed, herewith, are the results of the preliminary geotechnical subsurface exploration completed by Earth Engineering Consultants, Inc. (EEC) personnel for the referenced project. The proposed residential development is located north of the City of Fort Collins Utilities facility, south of the Cache La Poudre River and east of Wood Street in north-central Fort Collins, Colorado. For this study, a total of eight (8) preliminary test borings were drilled at select locations within the proposed development parcel. The preliminary borings were drilled to approximate depths of 15 to 30-feet below existing site grades. This study was completed in general accordance with our proposal dated October 21, 2011. In summary, the subsurface materials encountered in the preliminary test borings completed for this study consisted of apparent fill material and native slightly to moderately cohesive subsoils, generally classified as sandy lean clay, clayey silt, lean clay with sand and/or clayey sand with varying amounts of gravel, transitioning to a granular strata below. Silty sand with gavel and intermittent cobbles was encountered across the site in each of the borings at approximate depths of 2-1/2 to 7-feet below existing site grades and extended to the depths explored, or to the bedrock formation below. Claystone/siltstone bedrock with intermittent sandstone lenses was encountered in the deeper preliminary borings, (i.e., boring Nos. B-1, B-4, and B-7) at approximate depths of 13 to 18-feet below site grades and extended to the depths explored, approximately 30-feet. Groundwater was encountered during drilling operations in each of the preliminary test borings at approximate depths of 6 to 12-1/2-feet below site grades. Based on the materials observed within the preliminary boring locations and the anticipated foundation loads, we believe the proposed lightly loaded, single-story to 2-story residential structures, having slab-on-grade, crawl-space, or garden-level construction could be supported on PRELIMINARY SUBSURFACE EXPLORATION REPORT 912 WOOD STREET – PROPOSED RESIDENTIAL DEVELOPMENT FORMER BENDER MOBILE HOME PARK NORTH OF CITY OF FORT COLLINS UTILITIES AND SOUTH OF THE CACHE LA POUDRE RIVER FORT COLLINS, COLORADO EEC PROJECT NO. 1112069 November 17, 2011 INTRODUCTION The preliminary subsurface exploration for the proposed 912 Wood Street residential development, (AKA the former Bender Mobile Home Park), located north of the City of Fort Collins Utilities facility, south of the Cache La Poudre River and east of Wood Street in north- central Fort Collins, Colorado has been completed. For this study, a total of eight (8) preliminary test borings were drilled at select locations within the proposed development parcel. The preliminary borings were drilled to approximate depths of 15 to 30-feet below existing site grades. Individual boring logs and a site diagram indicating the approximate boring locations are provided with this report. We understand for this phase, approximately 8 to 10-acres of the approximate 18-acre parcel, will be developed for single family residential units along with associated on-site roadways to accommodate the anticipated traffic flow. The development will generally consist of approximately 15 larger sized estate lots along the northern and eastern perimeters, approximately 16 moderately sized residential lots along the southern perimeter and approximately 17 smaller/higher density/bungalow style lots within the interior portion of the proposed development area. The remaining acreage on-site along the northern and eastern boundaries will be developed as open-space areas with community theme concepts and orchards to preserve the historical characteristics of the property. The existing pond situated near the southeast portion of the site will be enlarged and converted to an on-site amenity. A preliminary site plan schematic overlain on a Google Earth aerial image is included herein to illustrate the proposed development plan. As shown on the enclosed site diagram/aerial photograph, the central portion of the site is currently occupied by several mobile homes along with various outbuildings. An existing residential home site with outbuildings is located near the southwest portion of the site. Generally throughout the property, various abandoned vehicles, car Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 2 parts, and domestic “junk” exists. The various mobile home sites, outbuildings, and “junk” are currently in the process of being removed and/or demolished on-site to make way for the proposed development. The existing mobile home sites are currently being serviced by a community on-site sewage disposal system, which will also be removed and new utility service lines will be installed. Minor grade changes are generally expected to develop final site grades, although the eastern portion of the site will be raised to “above flood plain” elevations. As shown on the enclosed site development improvement diagram, on-site pavement improvements are planned and will be coordinated and designed in general accordance with Larimer County Urban Area Street Standards (LCUASS) Pavement Design criteria. We anticipate proposed residential structures will have light loads with continuous wall loads less on the order of 1 to 3 kips per lineal foot and individual column loads on the order of 15 to 50 kips. Floor loads are expected to be light. If actual values differ from the estimated loads and assumptions presented herein, we should be contacted to review our design recommendations and provide supplemental design parameters, if warranted. The purpose of this report is to describe the subsurface conditions encountered in the preliminary borings, analyze and evaluate the test data and provide preliminary geotechnical recommendations concerning design and construction of the foundations and support of floor slabs and pavements. EXPLORATION AND TESTING PROCEDURES The boring locations were selected and located in the field by Earth Engineering Consultants, Inc. (EEC) personnel by pacing and estimating angles from identifiable site references. The approximate locations of the borings are indicated on the attached boring location diagram. The locations of those borings should be considered accurate only to the degree implied by the methods used to make the field measurements. The test borings were completed using a truck mounted, CME-45 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 3 using 4-inch nominal diameter continuous flight augers. Samples of the subsurface materials encountered were obtained using split barrel and California barrel sampling procedures. 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 and hardness of weathered bedrock. In the California barrel sampling procedure, relatively undisturbed samples are obtained in removable brass liners. 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. In addition, the unconfined strength of appropriate samples was estimated using a calibrated hand penetrometer. Atterberg Limits and washed sieve analysis tests were completed to evaluate the quantity and plasticity of fines in the subgrade samples. Swell/consolidation tests were completed to evaluate the potential for the subgrade materials to change volume with variation in moisture and load. 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 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 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. SUBSURFACE CONDITIONS An EEC field engineer was on site during drilling to evaluate the subsurface conditions encountered and direct the drilling activities. Field logs prepared by EEC site personnel were based on visual and tactual observation of disturbed samples and auger cuttings. The final boring logs included with this report may contain modifications to the field logs based on the results of Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 4 laboratory testing and evaluation. Based on the results of the field borings and laboratory evaluation, subsurface conditions can be generalized as follows. In summary, the subsurface materials encountered in the preliminary test borings completed for this study consisted of apparent fill material, in the general vicinity of boring Nos. B-3 and B-6, and native slightly to moderately cohesive subsoils, generally classified as sandy lean clay, clayey silt, lean clay with sand and/or clayey sand with varying amounts of silt and gravel, transitioning to the granular strata below. Silty sand with gavel and intermittent cobbles was encountered across the site in each of the borings at approximate depths of 2-1/2 to 7-feet below existing site grades and extended to the depths explored, or to the bedrock formation below. Claystone/siltstone bedrock with intermittent sandstone lenses was encountered in the deeper preliminary borings, (i.e., boring Nos. B-1, B-4, and B-7) at approximate depths of 13 to 18-feet below site and extended to the depths explored, approximately 30-feet. The bedrock consisted of moderately hard to hard claystone/siltstone with intermittent cemented to well-cemented sandstone lenses at increased depths. The bedrock soils were weathered nearer surface; however, became less weathered and more competent with depth. 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. Existing Fill Material Approximately 4 to 6-feet of apparent fill material was encountered in the general vicinity of boring Nos. B-3 and B-6. In the remaining borings fill material was not apparent; however variations may occur during construction and the fill depths may vary as well. The fill material, (generally classified as either clayey sand with trace amounts of gravel and/or sandy lean clay), in its in-situ condition should not be used for support of foundations, floor slabs, or support of pavements without ground modification and testing procedures. The existing fill material may be suitable for reuse provided ground modification procedures are implemented. It is recommended the existing fill material be over-excavated, moisture conditioned to near optimum moisture content (+/- 2%) of the material’s optimum moisture content as determined by ASTM D698), replaced in uniform lifts and re-compacted to a minimum of 95% of the materials’ standard Proctor density ASTM D698 characteristics. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 5 GROUNDWATER CONDITIONS Observations were made while drilling and a few days after completion of the borings to detect the presence and depth to hydrostatic groundwater. At the time of our field exploration and when checked a few days later, groundwater was encountered in each of the preliminary borings at approximate depths of 6 to 12-1/2-feet below site grades. The relatively shallow depth of groundwater may be attributed to the Cache La Poudre River which borders the site along the northern perimeter, and existing pond near the southeast corner of the site. 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. Monitoring in cased borings protected from the infiltration of surface water would be required to more accurately evaluate the depths and fluctuation in groundwater levels. Zones of perched and/or trapped groundwater may occur at times in the subsurface soils overlying bedrock, on top of the bedrock surface or within permeable fractures in the bedrock materials. The location and amount of perched water is dependent upon several factors, including hydrologic conditions, type of site development, irrigation demands on or adjacent to the site, fluctuation of volume with the meandering irrigation ditch along the northern perimeter of the property, and seasonal and weather conditions. The observations submitted with this report represent groundwater conditions at the time of the field exploration and may not be indicative of other times, or at other locations. ANALYSIS AND RECOMMENDATIONS General Considerations and Discussion of Native Overburden Soils The subject site is generally overlain by approximately 2 to 7-feet of either fill materials and/or native subsoils classified as silty clay, slightly cohesive silt soils and slightly to moderately plastic cohesive lean clay subsoils. Groundwater was also encountered at relatively shallow depths on the order of 6 to 12-1/2-feet below present site grades. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 6 High silt content soils can be problematic and certain precautions will be necessary during the design and construction phases of the site to minimize or reduce the potential impact/movement these soils may have. The silt soils and the slightly cohesive materials with elevated silt content are generally unstable at elevated moisture contents, susceptible to frost heave, (especially in areas where shallow groundwater is present) and silts are easily erodible. Frost heave potential can be reduced by using non-frost susceptible soils, removing the water source or reducing the exposure to freezing temperatures. Ground modification procedures as further discussed herein will be required to enhance the stability and structural integrity of these soils. The on-site cohesive clay soils would be suitable for reuse in select locations as fill material; however the silt soils should not be used as fill in structural related areas. The silt material could be reused in landscape portions of the site. Consideration could be given to the installation of an area underdrain system to lower or control the shallow groundwater levels as well as lower/decrease the moisture content of the overburden soils. Additional geotechnical engineering design recommendations regarding an area underdrain system can be provided upon request. Present site configuration and topography indicate that fill material will likely be required to achieve final grades. Final grading plans were not provided prior to the preparation of this preliminary subsurface exploration report; therefore the magnitude of the required fill thickness was not available to us at this time. We estimate about 1 to 5-feet of fill may be necessary in the area of the building envelopes and pavement areas. Consideration could be given to surcharge loading with fill material to reduce long-term movement of the soft/compressible overburden soils. Additional recommendations can be provided upon request. The recommendations contained in this report assume that fill will be required, and will be placed according to the specifications 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. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 7 Swell – Consolidation Test Results The swell-consolidation test is commonly performed to evaluate the swell or collapse potential of soils or bedrock for determining foundation, floor slab and pavement design criteria. In this test, relatively undisturbed samples obtained directly from the California sampler or thin-walled tubes are placed in a laboratory apparatus and inundated with water under a predetermined load. The swell-index is the resulting amount of swell or collapse after the inundation period, expressed as a percent of the sample’s initial thickness. Samples obtained at approximate depths of 1 to 2-feet are generally pre-loaded at 150-psf to simulate the pavement loading conditions, while samples obtained at greater depths are pre-loaded at 500 psf or 1000 psf to simulate the overburden soil pressures. All samples are inundated with water and monitored for swell and consolidation. After the inundation period additional incremental loads are applied to evaluate the swell pressure and consolidation. For this preliminary assessment, we conducted five (5) swell-consolidation tests on relatively undisturbed samples obtained at various intervals/depths and loading schemes throughout the site. The swell index values for the in-situ soil samples analyzed revealed low to moderate swell characteristics on the order of (-) 0.4 to (+) 3.7%. The (+) test results indicate the soil materials swell potential characteristics, while the (-) test results indicate the soil materials tendency to consolidate upon inundation with water and increased loads. The higher swell-index values, (i.e., the +1.9, and +3.7%) were samples inundated and pre-loaded at 150 psf to simulate pavement conditions. The swell-index test results for the underlying soil samples inundated and pre- loaded at 500 psf loading criteria varied from approximately (-) 0.4% to (+) 0.7%. The results of the five (5) swell-consolidation tests for samples collected at varies depths across the site within the preliminary soil borings are presented in the table below. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 8 TABLE I Summary of Swell-Consolidation Test Results Boring No. Depth, Ft. Description Swell-Consolidation Test Results In-Situ Moisture Content, % In-Situ Dry Density, PCF Dead Loading, PSF % Swell- Index +/- 1 4 Clayey Silt (CL-ML) 21.9 107.1 500 (-) 0.4 2 2 Silty, Clayey Sand (SC-SM) 11.4 106.3 150 (+) 1.9 5 4 Clayey Sand (SC) 11.2 108.3 500 (-) 0.2 7 4 Silt (ML) 6.6 107.3 500 (+) 0.7 8 2 Sandy Lean Clay (CL) 9.0 108.0 150 (+) 3.7 Colorado Association of Geotechnical Engineers (CAGE) uses the following information in Table II, to provide uniformity in terminology between geotechnical engineers to provide a relative correlation of slab performance risk to measured swell. “The representative percent swell values are not necessarily measured values; rather, they are a judgment of the swell of the soil and/or bedrock profile likely to influence slab performance.” Geotechnical engineers use this information to also evaluate the swell potential risks for foundation performance based on the risk categories. TABLE II: Recommended Representative Swell Potential Descriptions and Corresponding Slab Performance Risk Categories Slab Performance Risk Category Representative Percent Swell (500 psf Surcharge) Representative Percent Swell (1000 psf Surcharge) Low 0 to < 3 0 < 2 Moderate 3 to < 5 2 to < 4 High 5 to < 8 4 to < 6 Very High > 8 > 6 Based on the laboratory test results, the in-situ samples analyzed for this project at current moisture contents and dry densities generally were within the low range. In general, the (+) 3.7% swell- index test result was conducted on a sample pre-loaded and inundated at 150 psf, whereas CAGE does not have a specific category for pavement related swells, it is our opinion a comparable to pre- loading this sample at 500 psf might reveal a results of about 1-1/2 to possibly 2%. The sampling and testing completed for this preliminary evaluation was limited. Due to the boreholes caving in upon completion of the drilling operation within the granular zone, undisturbed samples of the bedrock were not obtained. It should be noted, that intermittent siltstone and/or claystone lenses Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 9 within the Cretaceous Pierre Formation may exhibit moderate to high swell-index values. A more complete testing protocol would be required during final design stages of the project. 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 5-feet of fill material may be necessary to achieve design grades. Existing fill material was encountered in a few of the preliminary soil borings as shown on the enclosed boring logs in the Appendix of this report, and may vary across the site. Due to the presence of the existing uncontrolled fill material, we recommend the existing fill zone in structural related areas, (i.e., beneath pavement, exterior flatwork, and building footprints) be removed and stockpiled for possible reuse as controlled/engineered fill material, where applicable. Additional laboratory testing will be required to verify the suitability/reuse of the existing fill material and field monitoring including moisture, density and percent compaction should be performed for compliance purposes. The preliminary recommendations contained in this report assume that earthwork activities will be required. Demolition of the existing Bender Mobile Home Park and various outbuildings, etc., should include complete removal of all foundation systems within the proposed residential construction/development area. This should include removal of any loose backfill found adjacent to existing foundations. All materials derived from the demolition of all existing structures and pavements should be removed from the site and either not be allowed for use in any on-site fills, or processed and re-evaluated for possible reuse. After stripping and completing all cuts and prior to placement of any fill or site improvements, we recommend the exposed soils be scarified to a minimum depth of 12-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 D-698. Due to the soft/compressible characteristics of native cohesive clay and silt soils, ground stabilization mechanism 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 soft soils, prior Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 10 to placement of 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 zone has been stabilized, should consist of approved, low-volume-change materials, which are free from organic matter and debris. It is our opinion the on-site cohesive clay soils could be used as general site fill outside of the building areas, provided adequate moisture treatment and compaction procedures are followed. We recommend structural fill materials be placed and compacted within the building footprint(s) and consist of essentially granular soils with less than 20% material passing the number 200 sieve, such as a CDOT Class 7 aggregate base course (ABC) type material or equivalent. 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-698, the standard Proctor procedure. If the site’s cohesive lean clay soils are used as fill material, care will be needed to maintain the recommended moisture content prior to and during construction of overlying improvements. Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade materials. Positive drainage should be developed away from the structures 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. Those materials should be placed in lifts and compacted to at least 70% relative density. Areas of deeper fills may experience settlement from underlying native soils and within the placed fill materials. Settlement on the order of 1-inch or more per each 10 feet of fill depth would be estimated. The rate of settlement will be dependent on the type of fill material placed and construction methods. This estimate is only for the fill materials, underlying softer subsoils beneath the fill zone would show additional settlement. Granular soils will consolidate essentially immediately upon placement of overlying loads. Cohesive soils will consolidate at a slower rate. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 11 Areas of shallow groundwater will also need to be addressed in the development; consideration could be given to the installation of an area underdrain system. Additional geotechnical engineering recommendations can be provided upon request. Foundation Systems – General Considerations The site appears is acceptable for the proposed construction based on the results of our field exploration and review of the proposed development plans. The slightly cohesive subsoils with elevated silt contents in this area will require particular attention in the design and construction to reduce the amount of movement, should the subsoils become elevated in moisture content with increased depth. The following foundation systems were evaluated for use on the site; however final subsurface explorations should be performed after building footprints have been more defined and actual design loads determined:  Conventional type spread footings bearing on native subsoils or engineered controlled fill material.  Post-Tensioned-Slab foundation system bearing on native subsoils or engineered controlled fill material, and  Grade beams and straight shaft piers/caissons drilled into the bedrock Preliminary Foundation Systems - Conventional Type Spread Footings With the anticipated loads, the type of construction proposed and the soil conditions encountered, the proposed lightly to slightly moderately loaded residential type structures could probably be supported using a conventional type spread footing foundation system bearing on approved native subsoils, approved moisture conditioned engineered/controlled fill material, or on a zone of approved imported fill material. Consideration should be given for placement of a uniform zone of material placed/prepared and compacted beneath the entire building footprint(s) to reduce differential movement. The depth of the fill material may vary with each building footprint/lot and owners risk tolerance. We would expect a minimum depth of 3 feet below foundation bearing elevation. However, a final/more thorough subsurface exploration should be performed for each Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 12 residential lot after final design layout of the proposed development and actual design loads are more defined. It is our opinion, the on-site upper native cohesive subsoils, and/or moisture conditioned engineered fill material would be capable of supporting a foundation systems designed using a maximum net allowable bearing pressure ranging from 1,000 to 2,000 psf. For preliminary design purposes, a minimum dead load pressure may not be warranted. Higher allowable bearing pressures could be achieved with the use of imported essentially granular structural fill materials. For fill material placement, full-time quality control measures should be performed to verify compliance to the project specifications. Footings for each residential structure should be placed on similar soils to reduce the potential for differential movement between soil types. Footings should be proportioned to reduce differential foundation movement. Proportioning on the basis of equal total movement is recommended; however, proportioning to relative constant dead-load pressure will also reduce differential movement between adjacent footings. Quality control/field monitoring should include but not limited to moisture content, dry density, percent compaction, swell mitigation to less than 1% when inundated and pre-loading at 500 psf and less than 2% when inundated and pre-loaded at 150 psf, and lift thicknesses for the fill material being placed. Areas of loose soils may be encountered at foundation bearing depths after excavation is completed for the residential footings. When such conditions exist beneath planned footing areas, the subgrade soils should be compacted prior to placement of the foundation system. In addition, large cobbles or boulder sized materials may be encountered beneath footing areas. Such conditions could create point loads on the bottom of footings, increasing the potential for differential foundation movement. If such conditions are encountered in the footing excavations, the cobbles and/or boulder sized materials should be removed and be replaced with engineered fill, conditioned to near optimum moisture content and compacted. Exterior footings and foundations in unheated areas must be protected from frost action. The normal depth of frost protection in this area is estimated to be around 30-inches. Continuous wall footings would have minimum width in the range of 16-inches. Isolated column pads would have minimum dimensions on the order of 24-inches by 24-inches. Based upon the structural loading Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 13 conditions provided, larger footing sizes will be needed to accommodate actual foundation load and design requirements. In the site design, it is imperative that positive drainage be maintained during construction and throughout the life of the facility to minimize the potential for surface water infiltration. It is EEC’s opinion that sub-excavation and replacement with controlled/engineered fill material combined with good positive drainage will reduce the settlement/expansive potential and will create a more stable bearing stratum. However, movement potential cannot be eliminated in expansive and/or consolidation prone subgrade materials. Preliminary Foundation Systems – Post-Tensioned-Slabs (PTS) Due to the relatively shallow depths to groundwater and depending upon the amount fill material placed to elevate the residential building footprints, consideration could be given to the use of a post-tensioned-slab (PTS) on grade foundation system. Preliminary design criteria for the use of a PTS foundation for the “slightly compressible soil” case are presented in the following table. These values should not be used for final design foundations, only for preliminary design purposes. Table III – Preliminary PTS Design Criteria Maximum Allowable Bearing Pressure, psf 1,000 psf Edge Moisture Variation Distance, em Center Lift Condition, ft. 5.5 feet Edge Lift Condition, ft. 2.5 feet Total Soil Movement, δ 1 to 1-1/2-inches Slab-Subgrade friction coefficient,  on polyethelene sheeting 0.75 on cohesionless soils – (sands) 1.0 on cohesive soils – (clays) 2.0 Post-tensioned slabs, thickened or turn-down edges and/or interior beams should be designed and constructed with the requirements of the Post-Tensioning Institute (PTI) and the American Concrete Institute (ACI). Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 14 Preliminary Foundation Systems – Drilled Piers/Caissons As an alternative to the use of a spread footing or a PTS system, and depending upon final layout, amount of fill material placed and compacted, and design loads for each residential site, consideration could also be given to supporting the proposed residential structures on a grade beam and straight shaft drilled pier/caisson foundation system extending into the underlying bedrock formation. The bedrock stratum varies across the site, generally from about 13 to 20-feet below existing site grades; thus requiring relatively lengthy piers, possibly in the range of about 25 to 35- feet depending upon actual design loads. For axial compression loads, we expect the drilled piers could be designed using maximum end bearing pressures ranging between 15,000 to 30,000 pounds per square foot (psf), along with a skin-friction values ranging between 1,500 to 3,000 psf for the portion of the pier extended into the underlying firm and/or harder bedrock formation. Straight shaft piers are typically drilled a minimum of 10 to 15-feet into competent or harder bedrock and generally extend to minimum depths of 25-feet or greater below finish site grades. Final, lot- specific drilled pier recommendations, including laboratory testing, (i.e., swell-consolidation characteristics on the bedrock formation), would be provided after each lot has completed an independent subsurface exploration. The values provided herein are preliminary and should be confirmed at the time of a final exploration for each residential lot. Drilling caissons to design depth should be possible with conventional heavy-duty single flight power augers equipped with rock teeth on the majority of the site. However, areas of well- cemented sandstone bedrock lenses may be encountered throughout the site at various depths where specialized drilling equipment and/or rock excavating equipment may be required. Excavation penetrating the well-cemented sandstone bedrock may require the use of specialized heavy-duty equipment, together with rock augers and/or core barrels. Drilled shafts will most likely not remain open without stabilizing measures. Groundwater was encountered at varying depths at the time of our drilling operations. Therefore, encountering groundwater should be expected during drilled pier installation. Temporary casing could be needed to seal off the drill shafts from groundwater seams. Allowing water depths to stabilize and using tremie procedures to place the concrete could also be considered. However, pier concrete should be placed soon after completion of drilling and cleaning. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 15 Preliminary Floor Slab Design and Construction The variability of the existing overburden soils, (i.e., slightly expansive and slightly consolidation prone characteristics based on the preliminary test results), in close proximity to the slab subgrade elevation, could result in differential movement of slabs should these materials become elevated in moisture content. As presented on the boring logs and the swell-consolidation test results, the subsurface soils on the site exhibited low expansive and slightly consolidation prone characteristics. Therefore, subgrade modifications and positive drainage away from the building footprint(s) to reduce the potential for surface water infiltration from impacting the underlying slab subgrade material should be expected. Use of a structural floor system, which is structurally supported independent of the subgrade soils, is a positive means of reducing the potentially detrimental effects of floor movement. Structural floors should be used for any residential building where risk of some floor movement would not be acceptable. Floor slab and pavement subgrades should be prepared as outlined under “Site Preparation” in this report. As opposed to the use of a structural floor slab, assuming a greater potential risk for movement, we suggest ground modifications such either an overexcavation and replacement procedure, or elevating each site with a zone of imported structural fill material. For the over- excavation and replacement method, we would expect areas beneath the floor slabs, depending upon building location and subsurface profile as encountered during the final/more thorough field exploration would be undercut to depths of at least two (2) feet beneath the slab. The overexcavated areas would be backfilled with moisture conditioned on-site cohesive subsoils or imported structural fill to provide stable subgrades. Depending upon the final grade for each residential lot, placement and compaction of at least 2-feet of imported structural fill could be considered for use a stable/slab support zone. An underslab gravel layer or thin leveling course could be used underneath the concrete floor slabs and concrete pavement areas to provide a leveling course for the concrete placement. Greater or lesser overexcavation depths may be appropriate for each specific residential lot. Ground modification procedures, such as over-excavation and moisture conditioning measures will be required to reduce post-construction movement. However, post-construction movement Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 16 cannot be completely eliminated. The cohesive soil materials may also be subject to strength loss and instability when wetted. Preliminary Basement Design and Construction Groundwater was encountered across the site within the preliminary soil borings at approximate depths of 6 to 12-feet below existing site grades. If lower level construction for either garden- level or full-depth basements are being considered for the site, we would suggest that the lower level subgrade(s) be placed a minimum of 4-feet above maximum anticipated rise in groundwater levels, or a combination exterior and interior perimeter drainage system(s) be installed. To reduce the potential for groundwater to enter the lower level/basement area of the structure(s), installation of a dewatering system is recommended. The dewatering system should, at a minimum, include an underslab gravel drainage layer sloped to an interior perimeter drainage system. The following provide preliminary design recommendations for interior and exterior perimeter drainage systems. The drainage system should consist of a properly sized perforated pipe, embedded in free- draining gravel, placed in a trench at least 12 inches in width. The trench should be inset from the interior edge of the nearest foundation a minimum of 12 inches. In addition, the trench should be located such that an imaginary line extending downward at a 45-degree angle from the foundation does not intersect the nearest edge of the trench. Gravel should extend a minimum of 3 inches beneath the bottom of the pipe. The drainage system should be sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a sump and pump system. The underslab drainage layer should consist of a minimum 6-inch thickness of free-draining gravel meeting the specifications of ASTM C33, Size No. 57 or 67 or equivalent. Cross- connecting drainage pipes should be provided beneath the slab at minimum 15-foot intervals, and should discharge to the perimeter drainage system. Sizing of drainage pipe will be dependent upon groundwater flow into the dewatering system. Groundwater flow rates will fluctuate with permeability of the soils to be dewatered and the depth to which groundwater may rise in the future. Pump tests to determine groundwater flow Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 17 rates are recommended in order to properly design the system. For preliminary design purposes, the drainage pipe, sump and pump system should be sized for a projected flow of 1 x 10-3 cubic feet per second (cfs) per lineal foot of drainage pipe. Additional recommendations can be provided upon request and should be presented in final subsurface exploration reports for each residential lot. To reduce the potential for surface water infiltration from impacting foundation bearing soils and/or entering any planned below grade portion of any residential structure, installation of an exterior perimeter drainage system is recommended. This drainage system should be constructed around the exterior perimeter of the lower level/below grade foundation system, and sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a sump and pump system. The drainage system should consist of a properly sized perforated pipe, embedded in free- draining gravel, placed in a trench at least 12 inches in width. Gravel should extend a minimum of 3 inches beneath the bottom of the pipe, and at least 2 feet above the bottom of the foundation wall. The system should be underlain with a polyethylene moisture barrier, sealed to the foundation walls, and extending at least to the edge of the backfill zone. The gravel should be covered with drainage fabric prior to placement of foundation backfill. Preliminary Pavements – Design and Construction Recommendations We expect the site pavements will include areas designated as jurisdictional local residential roadways. For preliminary purposes we are using an assumed equivalent daily load axle (EDLA) rating of 10 for the pavement improvement area on-site. A final pavement design exploration and report will be required for the development and should conform to the requirements presented in the Larimer County Urban Area Street Standards (LCUASS) Pavement Design Guidelines. 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, and the laboratory test results, it is suggested for preliminary design purposes that the on-site pavement improvement areas, (i.e., the local residential roadway), be designed using an R-value of 10. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 18 Due to the slightly expansive characteristics of the overburden soils, (i.e., swell-index values in excess of 2% when inundated with water and pre-loaded at 150 psf), a swell mitigation plan may be necessary to reduce the potential for movement within the pavement sections. As presented in the “Site Preparation” and “Floor Slab” sections of this report we suggest over-excavating on the order of two (2) feet of the overburden soils and replacement of these soils as moisture conditioned/engineered fill material beneath pavement areas. Due to the potential pumping conditions which could develop in a moisture treatment process of on-site cohesive soils, we would suggest in conjunction with the under-excavation process, subgrade stabilization by incorporating at least 13 percent by weight, Class C fly ash, into the upper 12-inches of subgrade will also be needed. A determination of the subgrade stabilization requirements will be determined when the final pavement design exploration is completed in general accordance with LCUASS. Hot Mix Asphalt (HMA) underlain by crushed aggregate base course with or without a fly ash treated subgrade, and non-reinforced concrete pavement underlain by an approved subgrade zone are feasible alternatives for the proposed on-site pavement areas. 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. 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. It is, therefore, important to minimize moisture changes in the subgrade to reduce shrink/swell movements. Suggested preliminary pavement sections are provided below in Table IV. HMA pavements may show rutting and distress in truck loading and turning areas. Concrete pavements should be considered in those areas. A final pavement design thickness evaluation will be determined when the pavement design exploration is completed in general accordance with LCUASS. Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 19 TABLE IV – PRELIMINARY PAVEMENT SECTIONS Local Residential Roadways EDLA Reliability Resilient Modulus PSI Loss – (Initial 4.5, Terminal 2.3) 10 75% 3562 2.2 Design Structure Number 2.63 Composite Section without Fly Ash – Alternative A Hot Mix Asphalt (HMA) Grading S (75) PG 58-28 Aggregate Base Course ABC – CDOT Class 5 or 6 Design Structure Number 4" 8” (2.64) Composite Section with Fly Ash – Alternative B Hot Mix Asphalt (HMA) Grading S (75) PG 58-28 Aggregate Base Course ABC – CDOT Class 5 or 6 Fly Ash Treated Subgrade Design Structure Number 4" 6" 12″ (3.02) PCC (Non-reinforced) – placed on an approved subgrade layer 5-1/2″ 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 excessive 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. Final pavement design report, in general accordance with the Larimer County Urban Area Street Standards (LCUASS) pavement design criteria should be performed prior to pavement construction after the site utilities/infrastructure are installed and the subgrade are prepared/constructed to “rough” final subgrade elevations. 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 adjacent to the building and parking and drive areas to avoid features which would pond water adjacent to the pavement, foundations or Earth Engineering Consultants, Inc. EEC Project No. 1112069 November 17, 2011 Page 20 stemwalls. Placement of plants which require irrigation systems or could result in fluctuations of the moisture content of the subgrade material should be avoided adjacent to site improvements. Lawn watering systems should not be placed within 5 feet of the perimeter of the building and parking areas. Spray heads should be designed not to spray water on or immediately adjacent to the structure or site pavements. Roof drains should be designed to discharge at least 5 feet away from the structure and away from the pavement areas. It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. Excavation penetrating the bedrock or cemented soils may require the use of specialized heavy-duty equipment, together with drilling and blasting to facilitate rock break-up and removal. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. If excavations need to penetrate into the bedrock, ripping or jack-hammering may be needed to advance the excavation. Some additional effort may be necessary to extract boulder sized materials, particularly in deep narrow excavations such as utility trenches. Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. Excavations into the on-site soils may encounter a variety of conditions. Excavations into the on- site soils may encounter caving soils and most likely shallow groundwater, depending upon the final depth of excavation. 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. 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, Inc. EEC Project No. 1112069 November 17, 2011 Page 21 Seismic Considerations The project site is located in Seismic Risk Zone I of the Seismic Zone Map of the United States as indicated by the 1997 Uniform Building Code. Based upon the nature of the subsurface materials, Soil Profile Type "Sc" should be used for the design of structures for the proposed project (1997 Uniform Building Code, Table No. 16-J). A site classification "C" would be appropriate for the design of structures for the proposed project (2003 International Building Code, Table No. 1615.1.1). 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 and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of Bellisimo, Inc., for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is made. In the event that any changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by the geotechnical engineer. Additional exploration/evaluation will be necessary to provide specific recommendations for individual users/buildings in part, to match owner expectations with geotechnical recommendations. 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: 912 WOOD STREET DEVELOPMENT FORT COLLINS, COLORADO EEC PROJECT NO. 1112069 NOVEMBER 2011 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 _ _ CLAYEY SILT (CL-ML) 1 brown, moist, loose to medium dense _ _ 2 _ _ *Intermittent CLAYEY SAND lenses with depth 3 _ _ 4 _ _ CS 5 6 2000 21.9 102.5 24 6 58.3 <500 psf None _ _ 6 _ _ 7 _ _ SILTY SAND with GRAVEL (SM) 8 brown, _ _ very dense 9 _ _ *Intermittent COBBLES with increased depths SS 10 50/9" -- 2.5 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 50/8" -- 11.6 _ _ 16 _ _ 17 _ _ 18 _ _ * No Split-Spoon (SS) sample taken @ 19.0' 19 due to boring cave-in within granular strata _ _ SS 20 10.6 _ _ WEATHERED CLAYSTONE / SILTSTONE BEDROCK 21 Gray, moist, soft to moderately hard _ _ 22 *Interbedded SANDSTONE Lenses _ _ 23 _ _ * No Split-Spoon (SS) sample taken @ 24.0' 24 due to boring cave-in within granular strata _ _ 14.2 25 Continued on Sheet 2 of 2 _ _ Earth Engineering Consultants Auger Cuttings 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 Sheet 1 of 2 26 _ _ CLAYSTONE / SILTSTONE BEDROCK 27 Gray, moderately hard to hard _ _ 28 * No Split-Spoon (SS) sample taken @ 29.0' _ _ due to boring cave-in within granular strata 29 BOTTOM OF BORING DEPTH 29.0' _ _ 30 _ _ 31 _ _ 32 _ _ 33 _ _ 34 _ _ 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 _ _ SILTY CLAYEY SAND (SC-SM) 1 brown _ _ loose 2 _ _ % @ 150 PSF *Intermittent CLAYEY SAND (SC) Lenses CS 3 9 7000 11.4 104.2 25 8 48.7 850 psf 1.9% _ _ 4 _ _ SS 5 45 9000 11.2 _ _ SAND & GRAVEL 6 very dense to dense _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 50 -- 8.9 _ _ 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 44 -- 9.5 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 _ _ APPARENT FILL MATRIAL: 1 Sandy Lean Clay / Clayey Sand with Gravel _ _ brown, dry to moist medium stiff 2 _ _ CS 3 11 3000 4.9 107.9 _ _ 4 _ _ SILTY CLAYEY SAND (SC-SM) SS 5 10 7500 12.0 brown _ _ medium dense 6 _ _ 7 _ _ 8 _ _ 9 _ _ CS 10 26 3500 12.7 SAND & GRAVEL (SP-GP) _ _ medium dense to dense 11 _ _ 12 _ _ 13 _ _ 14 _ _ SS 15 39 -- 20.0 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 _ _ SILTY CLAYEY SAND (SC-SM) 1 brown _ _ 2 _ _ SAND & GRAVEL (SP-GP) 3 brown _ _ very dense 4 with cobbles _ _ SS 5 50 -- 3.0 _ _ *Intermittent COBBLES within granular zone at increased depth 6 _ _ 7 _ _ 8 _ _ 9 _ _ *SPT results: 20 blows per 2-inches, then "50/0" SS 10 20/2" -- 13.1 _ _ 11 _ _ 12 _ _ 13 _ _ WEATHERED CLAYSTONE / SILTSTONE / SANDSTONE 14 olive / grey _ _ moderately hard 15 _ _ 16 _ _ 17 _ _ 18 _ _ * No Split-Spoon (SS) sample taken @ 19.0' 19 due to boring cave-in within granular strata _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ SS 25 15.7 _ _ Earth Engineering Consultants Auger Cuttings 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 Sheet 1 of 2 26 _ _ WEATHERED CLAYSTONE / SILTSTONE / SANDSTONE 27 olive / grey, moderately hard to hard _ _ 28 * No Split-Spoon (SS) sample taken @ 19.0' _ _ due to boring cave-in within granular strata 29 BOTTOM OF BORING DEPTH 29.0' _ _ 30 _ _ 31 _ _ 32 _ _ 33 _ _ 34 _ _ 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 _ _ SILTY CLAYEY SAND (SC-SM) 1 brown _ _ medium dense 2 _ _ 3 _ _ 4 *Intermittent CLAYEY SAND (SC) Lenses _ _ CS 5 10 9000 11.2 111.8 26 9 45.6 <500 psf None _ _ 6 _ _ 7 _ _ SAND & GRAVEL 8 brown _ _ medium dense 9 _ _ SS 10 28 -- 8.9 _ _ 11 _ _ 12 _ _ 13 *Intermittent COBBLES with increased depths _ _ 14 _ _ SS 15 50 -- 15.5 _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 _ _ APPARENT FILL MATERIAL: 1 SANDY LEAN CLAY with GRAVEL (CL) _ _ brown, stiff to very stiff 2 with traces of gravel _ _ 3 _ _ 4 _ _ CS 5 19 9000+ 3.8 116.4 _ _ 6 SAND & GRAVEL (SP-GP) _ _ brown 7 dense _ _ 8 _ _ 9 _ _ SS 10 50 -- 2.1 _ _ 11 _ _ 12 _ _ 13 _ _ 14 * No Split-Spoon (SS) sample taken @ 14.0' _ _ due to boring cave-in within granular strata SS 15 -- _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 SILT (ML) _ _ brown 2 medium dense _ _ 3 _ _ 4 _ _ CS 5 12 5000 6.6 100.0 NL NP 67.0 1000 psf 0.7% _ _ SAND & GRAVEL (SP-GP) 6 very dense _ _ 7 _ _ 8 _ _ 9 _ _ SS 10 50 -- 4.4 _ _ 11 _ _ 12 _ _ 13 _ _ * No Split-Spoon (SS) sample taken @ 14.0' 14 due to boring cave-in within granular strata _ _ 15 _ _ 16 _ _ 17 _ _ 18 _ _ WEATHERED CLAYSTONE / SILTSTONE BEDROCK 19 Gray, moist, soft to moderately hard _ _ SS 20 23.4 _ _ 21 _ _ 22 _ _ 23 _ _ * No Split-Spoon (SS) sample taken @ 24.0' 24 due to boring cave-in within granular strata _ _ 25 Continued on Sheet 2 of 2 _ _ Earth Engineering Consultants Auger Cuttings 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 Sheet 1 of 2 26 _ _ SANDSTONE / SILTSTONE 27 grey, hard to well-cemented with SANDSTONE lenses _ _ 28 _ _ *Intermittent SANDSTONE lenses 29 _ _ SS 30 50/3" 9000+ 14.7 _ _ BOTTOM OF BORING DEPTH 30.5' 31 _ _ 32 _ _ 33 _ _ 34 _ _ 35 _ _ 36 _ _ 37 _ _ 38 _ _ 39 _ _ 40 _ _ 41 _ _ 42 _ _ 43 _ _ 44 _ _ 45 _ _ 46 _ _ 47 _ _ 48 _ _ 49 _ _ 50 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT 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 % @ 150 PSF TOPSOIL & VEGETATION _ _ 1 SANDY LEAN CLAY (CL) _ _ brown 2 stiff to very stiff _ _ % @ 150 psf CS 3 6 9000+ 9.0 106.9 30 14 63.7 1600 psf 3.7% _ _ 4 _ _ SS 5 19 3000 6.0 _ _ SAND & GRAVEL (SP-GP) 6 brown _ _ dense 7 _ _ 8 *Intermittent COBBLES with increased depths _ _ 9 _ _ *SPT results: 3 blows per 3-inches, then "50/0" SS 10 3/3" -- 8.4 _ _ 11 _ _ 12 _ _ 13 _ _ 14 * No Split-Spoon (SS) sample taken @ 14.0' _ _ due to boring cave-in within granular strata SS 15 -- _ _ BOTTOM OF BORING DEPTH 15.5' 16 _ _ 17 _ _ 18 _ _ 19 _ _ 20 _ _ 21 _ _ 22 _ _ 23 _ _ 24 _ _ 25 _ _ Earth Engineering Consultants 912 WOOD STREET DEVELOPMENT SWELL / CONSOLIDATION TEST RESULTS % Swell @ 500: Project: Project #: Date: 1112069 November 2011 Swell Pressure: <500 psf 912 Wood Street Development Fort Collins, Colorado None Beginning Moisture: 21.9% Dry Density: 107.1 pcf Ending Moisture: 17.8% Material Description: Sample Location: Liquid Limit: 24 Plasticity Index: 6 Brown CLAYEY SILT (CL-ML) Boring 1, Sample 1, Depth 4' % Passing #200: 58.3% -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) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS % Swell @ 150: Project: Project #: Date: Material Description: Brown SILTY, CLAYEY SAND (SC/SM) Sample Location: Boring 2, Sample 1, Depth 2' Liquid Limit: 25 Plasticity Index: 8 % Passing #200: 48.7% Beginning Moisture: 11.4% Dry Density: 106.3 pcf Ending Moisture: 19.4% Swell Pressure: 850 psf 1.9% 912 Wood Street Development Fort Collins, Colorado 1112069 November 2011 -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) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS % Swell @ 500: Project: Project #: Date: Material Description: Brown CLAYEY SAND (SC) Sample Location: Boring 5, Sample 1, Depth 4' Liquid Limit: 26 Plasticity Index: 9 % Passing #200: 45.6% Beginning Moisture: 11.2% Dry Density: 108.3 pcf Ending Moisture: 21.3% Swell Pressure: <500 psf None 912 Wood Street Development Fort Collins, Colorado 1112069 November 2011 -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) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS % Swell @ 500: Project: Project #: Date: Material Description: Brown SILT (ML) Sample Location: Boring 7, Sample 1, Depth 4' Liquid Limit: NL Plasticity Index: NP % Passing #200: 67.0% Beginning Moisture: 6.6% Dry Density: 107.3 pcf Ending Moisture: 21.3% Swell Pressure: 1000 psf 0.7% 912 Wood Street Development Fort Collins, Colorado 1112069 November 2011 -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) Water Added Consolidation Swell SWELL / CONSOLIDATION TEST RESULTS % Swell @ 150: Project: Project #: Date: Material Description: Brown SANDY LEAN CLAY (CL) Sample Location: Boring 8, Sample 1, Depth 2' Liquid Limit: 30 Plasticity Index: 14 % Passing #200: 63.7% Beginning Moisture: 9.0% Dry Density: 108 pcf Ending Moisture: 20.8% Swell Pressure: 1600 psf 3.7% 912 Wood Street Development Fort Collins, Colorado 1112069 November 2011 -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) Water Added Consolidation Swell Client: Bellisimo, Inc. Project: 912 Wood Street Development Project No: 1112069 Sample Id: B-2, S-2, at 4' Date: November 2011 Initial Moisture Content of Delivered Sample 10.6% EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS Sieve Size 100 100 Percent Passing 69 67 100 95 95 93 No. 8 90 85 1/2" 3/8" No. 4 79 3" 2" 1 1/2" 1" 3/4" No. 40 No. 50 No. 100 No. 200 -- 73 70 No. 16 No. 30 -- 60 -- Liquid Limit Plastic Limit Plasticity Index 47.6 Liquid Limit, Plastic Limit and Plasticity Index of Soils (AASHTO T 89 & T90/ASTM D 4318) # # 00 00 # # # # Project: 912 Wood Street Development Project Number: Sample Id: B-2, S-2, at 4' Date: Medium Cobble Silt or Clay Fine Summary of Washed Sieve Analysis Tests (ASTM C-117 & C-136) November 2011 EARTH ENGINEERING CONSULTANTS, INC. 1112069 Gravel Sand Coarse Fine Coarse 0 10 20 30 40 50 60 70 80 90 100 1000 100 10 1 0.1 0.01 Percent Finer by Weight Grain Size in Millimeters 5" 3" 1" /2" No. 4 No. 16 No. 40 No. 100 6" 4" 2" 3/4" 3/8" No. 8 No. 30 No. 50 No. 200 Client: Bellisimo, Inc. Project: 912 Wood Street Development Project No: 1112069 Sample Id: B-4, S-2, at 4' Date: November 2011 Initial Moisture Content of Delivered Sample 2.8% EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS Sieve Size 100 100 Percent Passing 21 17 100 90 85 75 No. 8 69 57 1/2" 3/8" No. 4 47 3" 2" 1 1/2" 1" 3/4" No. 40 No. 50 No. 100 No. 200 -- 35 25 No. 16 No. 30 -- 11 -- Liquid Limit Plastic Limit Plasticity Index 7.4 Liquid Limit, Plastic Limit and Plasticity Index of Soils (AASHTO T 89 & T90/ASTM D 4318) # # 00 00 # # # # Project: 912 Wood Street Development Project Number: Sample Id: B-4, S-2, at 4' Date: Medium Cobble Silt or Clay Fine Summary of Washed Sieve Analysis Tests (ASTM C-117 & C-136) November 2011 EARTH ENGINEERING CONSULTANTS, INC. 1112069 Gravel Sand Coarse Fine Coarse 0 10 20 30 40 50 60 70 80 90 100 1000 100 10 1 0.1 0.01 Percent Finer by Weight Grain Size in Millimeters 5" 3" 1" /2" No. 4 No. 16 No. 40 No. 100 6" 4" 2" 3/4" 3/8" No. 8 No. 30 No. 50 No. 200 Client: Bellisimo, Inc. Project: 912 Wood Street Development Project No: 1112069 Sample Id: B-5, S-2, at 9' Date: November 2011 -- 15 -- Liquid Limit Plastic Limit Plasticity Index 10.3 Liquid Limit, Plastic Limit and Plasticity Index of Soils (AASHTO T 89 & T90/ASTM D 4318) No. 40 No. 50 No. 100 No. 200 -- 30 27 No. 16 No. 30 3" 2" 1 1/2" 1" 3/4" No. 8 64 56 1/2" 3/8" No. 4 48 Percent Passing 26 21 100 86 76 69 Initial Moisture Content of Delivered Sample 8.9% EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS Sieve Size 100 100 # # 00 00 # # # # Project: 912 Wood Street Development Project Number: Sample Id: B-5, S-2, at 9' Date: EARTH ENGINEERING CONSULTANTS, INC. 1112069 Gravel Sand Coarse Fine Coarse Medium Cobble Silt or Clay Fine Summary of Washed Sieve Analysis Tests (ASTM C-117 & C-136) November 2011 0 10 20 30 40 50 60 70 80 90 100 1000 100 10 1 0.1 0.01 Percent Finer by Weight Grain Size in Millimeters 5" 3" 1" /2" No. 4 No. 16 No. 40 No. 100 6" 4" 2" 3/4" 3/8" No. 8 No. 30 No. 50 No. 200 Client: Bellisimo, Inc. Project: 912 Wood Street Development Project No: 1112069 Sample Id: B-6, S-2, at 9' Date: November 2011 Initial Moisture Content of Delivered Sample 2.1% EARTH ENGINEERING CONSULTANTS, INC. Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136) SUMMARY OF LABORATORY TEST RESULTS Sieve Size 100 100 Percent Passing 27 22 100 94 81 75 No. 8 71 62 1/2" 3/8" No. 4 52 3" 2" 1 1/2" 1" 3/4" No. 40 No. 50 No. 100 No. 200 -- 42 32 No. 16 No. 30 -- 15 -- Liquid Limit Plastic Limit Plasticity Index 10.3 Liquid Limit, Plastic Limit and Plasticity Index of Soils (AASHTO T 89 & T90/ASTM D 4318) # # 00 00 # # # # Project: 912 Wood Street Development Project Number: Sample Id: B-6, S-2, at 9' Date: Medium Cobble Silt or Clay Fine Summary of Washed Sieve Analysis Tests (ASTM C-117 & C-136) November 2011 EARTH ENGINEERING CONSULTANTS, INC. 1112069 Gravel Sand Coarse Fine Coarse 0 10 20 30 40 50 60 70 80 90 100 1000 100 10 1 0.1 0.01 Percent Finer by Weight Grain Size in Millimeters 5" 3" 1" /2" No. 4 No. 16 No. 40 No. 100 6" 4" 2" 3/4" 3/8" No. 8 No. 30 No. 50 No. 200 FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-8 (PIEZOMETER) SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 9.5-10.0' FINISH DATE 11/4/2011 11/8/2011 8.4' SURFACE ELEV N/A 11/14/2011 8.4' A-LIMITS SWELL PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-7 SHEET 2 OF 2 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 10.0' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL 912 WOOD STREET DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-7 SHEET 1 OF 2 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 10.0' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-6 (PIEZOMETER) SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING None FINISH DATE 11/4/2011 11/8/2011 >7.3' SURFACE ELEV N/A 11/14/2011 >7.3' A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-5 SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 9.0' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-4 SHEET 2 OF 2 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 6.0' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL 912 WOOD STREET DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-4 SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 6.0' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-3 SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 10.5' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-2 (PIEZOMETER) SHEET 1 OF 1 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 9.5' FINISH DATE 11/4/2011 11/8/2011 8.2' SURFACE ELEV N/A 11/14/2011 8.2' A-LIMITS SWELL PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-1 SHEET 2 OF 2 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 12.5' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL Auger Cuttings 912 WOOD STREET DEVELOPMENT FORT COLLINS, COLORADO PROJECT NO: 1112069 NOVEMBER 2011 LOG OF BORING B-1 SHEET 1 OF 2 WATER DEPTH START DATE 11/4/2011 WHILE DRILLING 12.5' FINISH DATE 11/4/2011 AFTER DRILLING N/A SURFACE ELEV N/A 24 HOUR N/A A-LIMITS SWELL 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