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HomeMy WebLinkAboutBRIDGEFIELD P.U.D., PHASE I - FINAL - 45-94A - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGeotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955.007 Terracon The Geotechnical Engineer should also be retained to provide services during excavation, grading, foundation and construction phases of the work. Observation of footing excavations should be performed prior to placement of reinforcing and concrete to conform that satisfactory bearing materials are present and is considered a necessary part of continuing geotechnical engineering services for the project. Construction testing, including field and laboratory evaluation of fill, backfill, pavement materials, concrete and steel should be performed to determine whether applicable project requirements have been met. It would be logical for Empire Laboratories, Inc. to provide these additional services for continuing from design through construction and to determine the consistency of field conditions with those data used in our analyses. The analyses and recommendations in this report are based in part upon data obtained from the field exploration. The nature and extent of variations beyond the location of test borings may not become evident until construction. If variations then appear evident, it may be necessary to re-evaluate the recommendations of this report. Our professional services were performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical engineers practicing. in this or similar localities. No warranty, express or implied, is made. We prepared the report as an aid in design of the proposed project. This report is not a bidding document. Any contractor reviewing this report must draw his own conclusions regarding site conditions and specific construction techniques to be used .on this project. This report is for the exclusive purpose of providing geotechnical engineering and/or testing information and recommendations. The scope of services for this project does not include, either specifically or by implication, any environmental assessment of the site or identification of contaminated or hazardous materials or conditions. If the owner is concerned about the potential for such contamination, other studies should be undertaken. 15 Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 3. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving. 4. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscaped irrigation adjacent to the foundation system should be minimized or eliminated. Additional Design and Construction Considerations: • Exterior Slab Design and Construction: Exterior slabs -on -grade, exterior architectural features, and utilities founded on, or in backfill may experience some movement due to the volume change of the backfill. Potential movement could be reduced by: • minimizing moisture increases in the backfill • controlling moisture -density during placement of backfill • using designs which allow vertical movement between the exterior features and' adjoining structural elements • placing effective control joints on relatively close centers. • allowing vertical movements in utility connections I • Corrosion Protection: Results of soluble sulfate testing indicate that ASTM Type 1/II Portland cement is suitable for all concrete on and below grade. Foundation I concrete should be designed in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4. I GENERAL COMMENTS It is recommended that the Geotechnical Engineer be retained to provide a general review of final design plans and specifications in order to confirm that grading and foundation recommendations have been interpreted and implemented. In the event that any changes of the proposed project are planned, the conclusions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary. 14 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon 5. On -site clay soils placed around or beneath the foundations should be compacted within a moisture content range of optimum to 2 percent above optimum. On -site clay soils beneath pavements should be compacted within a moisture content range of 2 percent below to 2 percent above optimum. Granular soils should be. compacted within a moisture content range of 3 percent below to 3 percent above optimum. • Compliance: Performance of slabs -on -grade, foundations and pavement elements supported on compacted fills or prepared subgrade depend upon compliance with "Earthwork" recommendations. To assess compliance, observation and testing should be performed under the direction of the geotechnical engineer. • Excavation and Trench Construction: Excavations into the on -site soils will encounter a variety of conditions. Excavations into the clays can be expected to stand on relatively steep temporary slopes during construction. However, caving granular soils will likely be encountered. The individual contractor(s) should be made responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards. Drainage: • Surface Drainage: 1. Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Infiltration of water into utility or foundation excavations must be prevented during construction. Planters and other surface features which could retain water in areas adjacent to the building or pavements should be sealed or eliminated. 2. In areas where sidewalks or paving do not immediately adjoin a structure, we recommend that protective slopes be provided with a minimum grade of approximately 10 percent for at least 10 feet from perimeter walls. Backfill against footings, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. 13 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 • general site grading • foundation areas • interior floor slab areas Terracon • exterior slab areas • pavement areas • foundation backfill 2. Frozen soils should not be used as fill or backfill. 3. Aggregate base should conform to Colorado Department of Transportation Class 5 or 6 specifications. • Placement and Compaction: 1. Place and compact fill in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. 2. No fill should be placed over frozen ground. 3. Materials should be compacted to the following: Minimum Percent Material (ASTM D698) Subgrade soils beneath fill areas ..................... 95 On -site soils or approved imported fill: Beneath foundations ......................... 98 Beneath slabs ............................. 95 Beneath pavements ......................... 95 Utility trenches beneath construction ............. 95 Utility trenches in open areas ................... 90 Aggregate base (beneath pavement) ................... 95 Miscellaneous backfill .............................. 90 4. If a well defined maximum density curve cannot be generated by impact compaction in the laboratory for any fill type, engineered fill should be compacted to a minimum of 80 percent relative density by determined by ASTM D4253. 12 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon 2. Demolition of the existing building should include removal of the entire foundation. If unexpected fills or underground facilities are encountered during site clearing, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. All excavations should be observed by the geotechnical engineer prior to backf ill placement. 3. Stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to revegetate exposed slopes after completion of grading operations. 4. All materials derived from the demolition of existing structures should be removed from the site, and not be allowed for use in any on -site fills. 5. All exposed areas which will receive pavement, fill and/or upper level floor slabs, once properly cleared, should be scarified to a minimum depth of 8 inches, conditioned to near optimum moisture content and compacted. • Pavement Subgrade Preparation: On -site clay soils may pump or become unstable or unworkable at high water contents. Workability may be improved by scarifying and drying. Overexcavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce subgrade pumping. Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction. Proofrolling the subgrade may be required to determine stability prior to paving. I• Fill Materials: 1. Clean on -site soils or approved imported materials may be used as fill material for the following: Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon Future performance of pavements constructed on the clay soils at this site will be dependent upon several factors, including: • maintaining stable moisture content of the subgrade soils; and, • providing for a planned program of preventative maintenance. Since the clay soils on the site have shrink/swell characteristics, pavements could crack in the future primarily because of expansion of the soils when subjected to an increase in moisture content to the subgrade. The cracking, while not desirable, does not necessarily constitute structural failure of the pavement. The performance of all pavements can be enhanced by minimizing excess moisture which can reach the subgrade soils. The following recommendations should be considered at minimum: • Site grading at a minimum 2% grade away from the pavements; • Compaction of any utility trenches for landscaped areas to the same criteria as the pavement subgrade; • Sealing all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration to subgrade soils; • Placing compacted backfill against the exterior side of curb and gutter; and, J • Placing curb, gutter and/or sidewalk directly on subgrade soils without the use of base course materials. Earthwork: • Site Clearin4: I 1. Strip and remove existing vegetation, debris, existing foundations and other deleterious materials from proposed building and pavement areas. . All exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. 10 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon �y Plant -mixed bituminous base course should be composed of a mixture of aggregate, filler J and additives if required, and approved bituminous material. The bituminous base should. conform to an approved mix design stating the Marshall or Hveem properties, optimum . asphalt content, job mix formula, and recommended mixing and placing temperatures. Aggregate used in plant -mixed bituminous base course should meet a particular gradation. Use of aggregates meeting Colorado Department of Transforation Grading G or C specifications is recommended. The mix design should be submitted prior .to construction to verify it adequacy. The asphalt material should be placed in maximum 3-inch lifts, and should be compacted to a minimum of 95% Marshall or Hveem density (ASTM D1559). Where rigid pavements are used, the concrete should be obtained from an approved mix design with the following minimum properties: I I • Modulus of Rupture @ 28 days ................. 650 psi minimum • Strength Requirements ........................... ASTM C94 • Minimum Cement Content ..................... 6.5 sacks/cu. yd. • Cement Type ................................ Type I Portland • Entrained Air Content .............................. 6 to 8% • Concrete Aggregate ............ ASTM C33 and CDOT Section 703 • Aggregate Size ............................. 1 inch maximum • Maximum Water Content ................... 0.49 lb/lb of cement • Maximum Allowable Slump .......................... 4 inches Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes from time the water is added to the mix. Other specifications outlined by the Colorado Department of Transportation should be followed. 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 and should be placed (in feet), at roughly twice the slab thickness (in inches), on center in either direction. Sawed joints should be cut within 24- hours of concrete placement, and should be a minimum of 25% of slab thickness plus 1 /4 inch. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer. Where dowels cannot be used at joints accessible to wheel loads, pavement thickness should be increased by 25 percent at the joints and tapered to regular thickness in 5 feet. 9 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon Recommended alternatives for flexible and rigid pavements, summarized for each traffic area, are as follows: Recommended Pavement Section Thickness (inches) Asphalt Concrete Aggregate Base Plant -Mixed Bituminous Portland Cement Total Traffic Area Alternative Surface Course Base Concrete A 4 12 16 B 3 5 B Bridgefield Drive C 6 6 (Collector) All Other A 3 9 12 B 2 4 6 Public Streets C 6 5 and Private Drives Each alternative should be investigated with respect to current material availability and economic conditions. Aggregate base course (if used on the site) should consist of a blend of sand and gravel which meets strict specifications for quality and gradation. Use of materials meeting Colorado Department of Transportation Class 5 or 6 specifications is recommended. In addition, the base course material should be moisture stable. Moisture stability is determined by R-value testing which shows a maximum 12 point difference in R-values between exudation pressures of 300 psi and 100 psi. Aggregate base course material should be tested to determined compliance with these specifications prior to importation to the site. Aggregate base course should be placed in lifts not exceeding six inches and should be compacted to a minimum of 95% Standard Proctor density (ASTM D698). Asphalt concrete should be obtained from an approved mix design stating the Marshall or Hveem properties, optimum asphalt content, job mix formula, and recommended mixing and placing temperatures. Aggregate used in asphalt concrete should meet a particular gradation. Use of materials meeting Colorado Department of Transportation Grading C or CX specification is recommended. The mix design should be submitted prior to construction to verify its adequacy. The asphalt materials should be placed in maximum 3-inch lifts, and should be compacted to a minimum of 95% Marshall or Hveem density (ASTM D1559). 8 �J I I] J J I Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 Based upon AASHTO criteria, Colorado is located within Climatic Region VI of the United States. This region is characterized as being dry, with hard ground freeze and spring thaw. The spring thaw condition typically results in saturated or near -saturated subgrade soil moisture conditions. The AASHTO criteria suggests that these moisture conditions are prevalent for approximately 12-1/2% of the annual moisture variation cycle. Local drainage characteristics of proposed pavement areas are considered to be good. These characteristics, coupled with the approximate duration of saturated subgrade conditions, results in a design drainage coefficient of 1.0 when applying the AASHTO criteria for design. For flexible pavement design, a terminal serviceability index of 2.0 was utilized along with an inherent reliability of 85% for the collector street and 70% for all other streets and drives. Using a design R-value of 5, appropriate EDLA, environmental criteria and other factors, the structural numbers (SN) of the pavement sections were determined on the basis of the 1986 AASHTO design equation. In addition to the flexible pavement design analyses, a rigid pavement design analysis was completed, based upon AASHTO design procedures. Rigid pavement design is based on an evaluation of the Modulus of Subgrade Reaction of the soils (K-value), the Modulus of Rupture of the concrete, and other factors previously outlined. The design K-value of 100 for the subgrade soil was determined by correlation to the laboratory tests results. A modulus of rupture of 650 psi (working stress 488 psi) was used for pavement concrete. The rigid pavement thicknesses for each traffic category were determined on the basis of the AASHTO design equation. 7 Geotechnical Engineering Exploration Lagunitas Company ELI Project No. 20955007 Additional floor slab design and construction recommendations are as follows: Terracon • Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement. • Contraction joints should be provided in slabs to control the location and extent of cracking. Maximum joint spacing of 15 to 20 feet in each direction is recommended. • A minimum 1'/s-inch void space should be constructed above, or below non - bearing partition walls placed on the floor slab. Special framing details should be provided at door jambs and frames within partition walls to avoid potential distortion. Partition walls should be isolated from suspended ceilings. • Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined below. • In areas subjected to normal loading, a minimum 4-inch layer of aggregate base course shouldbe placed beneath interior slabs. • Floor slabs should not be constructed on frozen subgrade. J • Other design and construction considerations, as outlined in the ACI Design Manual, Section 302A R are recommended. Pavement Design and Construction: Design of pavements for the project have been based on the procedures outlined in the 1986 Guideline for Design of Pavement Structures by the American Association of State Highway and Transportation Officials (AASHTO). Areas I within proposed pavements on the site will be divided into two categories. based upon anticipated. traffic and usage. Traffic criteria provided for pavement thickness designs include 18-kip equivalent daily load applications (EDLA) of 20 for the collector street (Bridgefield Drive) and 5 for all public, local streets. An EDLA of 5 was also used for all private, residential drives. 6 3 Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 Existing fill on the site should not be used for support of foundations. Exterior footings should be placed a minimum of 30 inches below finished grade for frost protection. Interior footings should bear a minimum of 12 inches below finished grade. Finished grade is the lowest adjacent grade for perimeter footings and floor level for interior footings. Footings should be proportioned to minimize 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 or differential settlement resulting from the assumed structural loads are estimated to be on the order of 3/a, inch or less. 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. Foundations and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in masonry walls is recommended. Each foundation excavation should be observed by the geotechnical engineer. If the soil conditions encountered differ from those presented in this report, supplemental recommendations may be required. =� Basement Construction: Groundwater was not encountered on the site to the maximum depth of exploration, 15 feet. Therefore, full -depth basement construction is considered feasible. Floor Slab Design and Construction: Some differential movement of a slab -on -grade floor system is possible should the subgrade soils increase in moisture content. Such movements are considered within general tolerance for normal slab -on -grade construction. To reduce any potential slab movements, the subgrade soils should be prepared as outlined in the Earthwork section of this report. For structural design of concrete slabs -on -grade, a modulus of subgrade reaction of 150 pounds per cubic inch (pci) may be used for floors supported on existing or compacted soils at the site. I I 5 J Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 J Lean Clay with Sand: The upper clay stratum was encountered below the topsoil in borings 2, 3 and 4 and extends to depths of 1'/2 to 3Yz feet. This brown clay contains moderate quantities of sand and is moist in its in -situ condition. • Sandy Lean Clay with Gravel: The lower clay stratum was encountered at depths of 1'/z to 7Yz feet and extends to the depths explored. This tan and red clay contains substantial quantities of sand and moderate quantities of gravel, is interbedded with granular strata and is moist in its in -situ condition. r: • Clayey and/or Silty Sand with Gravel: The granular stratum was encountered below the fill in boring 1 and interbedded with the lower, red clay stratum in borings 3 and 4. The granular material is moist in its in -situ condition. i 1 ; Field and Laboratory Test Results: Field test results indicate the clay soils vary from stiff to very stiff in consistency. The sand soils vary from medium dense to dense in relative i, density. Laboratory test results indicate the clay soils at anticipated foundation depths have low to moderate expansive potential and moderate bearing capacity. Jt Groundwater Conditions: Groundwater was not observed in any test boring at the time of the field exploration, nor when checked two days after drilling. These observations represent only current groundwater conditions, and may not be indicative of other times, or at other locations. Groundwater levels can be expected to fluctuate with varying seasonal and weather conditions. CONCLUSIONS AND RECOMMENDATIONS Foundation Systems: Based on the soil conditions encountered on the site, spread footing and/or grade beam foundation systems bearing upon undisturbed subsoils are recommended for support of the proposed structures. The footings may be designed for a maximum bearing pressure of 2,000 psf. The design bearing pressure applies to dead loads plus '/2 design live load conditions. In addition, the footings should be sized to maintain a minimum dead load pressure of 750 psf. 4 Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 Selected soil samples were tested for the following engineering properties: • Water content • Liquid limit • Dry density • Plasticity Index • Compressive strength • Percent fines • Consolidation • R-Value • Expansion • Water soluble sulfate content The significance and purpose of each laboratory test is described in Appendix C. Laboratory test results are presented .on the boring logs and in Appendix B, and were used for the geotechnical engineering analyses, and the development of foundation, pavement and earthwork recommendations. All laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards. SITE CONDITIONS The site consists of approximately 8 acres of land vegetated with grass, weeds and deciduous trees. An existing residence is located near the center of the north edge of the property. The property is bordered by West Prospect Road to the north, Larimer County Canal No. 2 to the south and southeast, an existing residence to the east and New Mercer Ditch and the Bridges P.U.D. townhomes to the west. The north portion of the site exhibits surface drainage to the north and the south portion of the site exhibits surface drainage to the south. SUBSURFACE CONDITIONS Soil Conditions: As presented on the boring logs, the following describes the characteristics of the primary strata encountered at the site: • Topsoil: A '/z-foot layer of topsoil was encountered at the surface of Borings 2, 3 and 4. The topsoil has been penetrated by root growth and organic matter. • Fill: A 1'/z foot layer of fill was encountered at the surface of Boring 1. The fill consists of clayey sand with gravel and pieces of concrete. 3 Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 SITE EXPLORATION The scope of the services performed for this project included site reconnaissance by a geotechnical engineer, a subsurface exploration program, laboratory testing and engineering analyses. Field Exploration: A total of four test borings were drilled on January 25, 1995 to a depth of 15 feet at the locations shown on the Site Plan, Figure 1. Three borings were drilled in proposed building areas and one boring was drilled in the area of proposed pavement. All borings were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter solid stem auger. The borings were located in the field relative to the north property line. Elevations were taken at -each boring location with an engineer's level using a temporary bench mark (TBM) shown on the site plan. The accuracy of boring locations and elevations should only be assumed to the level implied by the methods used. Continuous lithologic logs of each boring were recorded by the geotechnical engineer, during the drilling operations. At selected intervals, samples of the subsurface materials were taken by pushing thin -walled Shelby tubes, or by driving split -spoon samplers. Representative bulk samples of subsurface materials were obtained from two borings. Penetration resistance measurements were obtained by driving the split -spoon into the subsurface materials with a 140-pound hammer falling 30 inches. The penetration resistance value is a useful index to the consistency, relative density or hardness of the materials encountered. Groundwater was not encountered in the test borings at the time of the site exploration nor when checked two days after drilling. Laboratory Testing: All samples retrieved during the field exploration were returned to .the laboratory for observation by the project geotechnical engineer, and were classified in accordance with the Unified Soil Classification System described in Appendix C. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Boring logs were prepared and are presented in Appendix A. 2 1 GEOTECHNICAL ENGINEERING REPORT Terracon BRIDGEFIELD P.U.D., PHASES I AND II WEST PROSPECT ROAD FORT COLLINS, COLORADO ELI Project No. 20955007 February 7, 1995 INTRODUCTION This report contains the results of our geotechnical engineering exploration for the proposed project to be located on the south side of West Prospect Road between South Shields Street and South Taft Hill Road in southwest Fort Collins, Colorado. The site is located in the N'/z of Section 22, Township 7 North, Range 69 West of the 6th Principal .Meridian. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: • subsurface soil conditions 0 groundwater conditions • foundation design and construction 0 basement construction • floor slab design and construction • pavement design and construction • earthwork 0 drainage The conclusions and recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, our experience with similar soil conditions and structures and our understanding of the proposed project. PROPOSED CONSTRUCTION Based on information provided concerning construction, the proposed structures will consist of 62 single-family and duplex residences. The buildings will be one and two-story structures with conventional basement construction. Residential drives and city streets will be constructed throughout the project area. Although final site grading plans were not available prior to preparation of this report, ground floor levels are anticipated to be at, or near existing site grades. J Geotechnical Engineering Exploration Lagunitas Company ELI Project.No. 20955007 TABLE OF CONTENTS (Cont'd) Terracon APPENDIX A Site Plan ........................................... Figure No. 1 Logs of Borings ...................................... Al thru A4 APPENDIX B Consolidation Tests ................................... 131 thru B2 R-Value................................................. B3 Summary of Test Results ............................... B4 thru B5 APPENDIX C: GENERAL NOTES Drilling & Exploration ....................................... C1 Unified Soil Classification ..................................... C2 Laboratory Testing, Significance and Purpose ...................... C3 Report Terminology .......................................... C4 APPENDIX D Recommended Preventative Maintenance -Asphalt Concrete Pavements .... D1 Recommended Preventative Maintenance -Jointed Concrete Pavements .... D2 Geotechnical Engineering Exploration Terracon Lagunitas Company ELI Project No. 20955007 TABLE OF CONTENTS Page No. Letter of Transmittal ............................................... i INTRODUCTION................................................ 1 PROPOSED CONSTRUCTION ...................................... 1 SITE EXPLORATION ............................................. 2 Field Exploration .......................................... 2 Laboratory Testing .......................................... 2 SITE CONDITIONS .............................................. 3 SUBSURFACE CONDITIONS ....................................... 3 Soil Conditions ............................................ 3 Field and Laboratory Test Results ............................... 4 Groundwater Conditions ..................................... 4 CONCLUSIONS AND RECOMMENDATIONS ............................. .4 Foundation Systems ...... I ................................. 4 Basement Construction ...................................... 5 Floor Slab Design and Construction ............................. 5 Pavement Design and Construction ............................. 6 Earthwork ............................................... 10 SiteClearing ........................................ 10 Pavement Subgrade Preparation ........................... 11 Fill Materials ........................................ . 11 Placement and Compaction .............................. 12 Compliance......................................... 13 Excavation and Trench Construction ........................ 13 Drainage................................................ 13 Surface Drainage ..................................... 13 Additional Design and Construction Considerations .................. 14 Exterior Slab Design and Construction ...................... 14 Corrosion Protection ................................... 14 GENERAL COMMENTS ........................................... 14 t Geotechnicai Engineering Exploration Lagunitas Company ELI Project No. 20955007 Terracon i We appreciate being of service in the geotechnical engineering phase of this project, and are prepared to assist during the design and construction phases as well. If you have any questions concerning this report or any of our testing, inspection, design and consulting services, please do not hesitate to contact us. Sincerely, J EMPIRE LABORATORIES, INC. scN ° A Division of The Terracon Companies, Inc. 237Q2 00 sa R. Schoenfeld, P.E. 's; ',;>r�°°° °°°•a`,,•';• Geotechnical Engineer Reviewed by: © v L _ c ''...• C0 •y _ Larry G. O'Dell, P.E. _ 2275p Office Manager LRS/LGO/dmf ',F�s�O#Ai•EN'�\��;; Copies to: Addressee (3) City of Fort Collins Planning Department (1) II II February 7, 1995 Lagunitas Company 3307 South College Avenue, Suite 200 Fort Collins, CO 80525 Attn: Mr. John Prouty Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. P.O. Box 503.301 No. Howes Fort Collins, Colorado 60522 (303) 484-0359 Fax (303) 484-0454 Chester C. Smith, P.E. Larry G. O'Dell, P.E. Neil R. Sherrod, C.P.G. Re: Geotechnical Engineering Report, Bridgefield P.U.D., Phases 1 and 11 West Prospect Road, Fort Collins, Colorado ELI Project No. 20955007 Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the proposed project to be located on the south side of West Prospect Road, south of South Bryan Avenue in southwest Fort Collins, Colorado. This study was performed in general accordance with our proposal number D2095018 dated January 18, 1995. The results of our engineering study, including the boring location diagram, laboratory test results, test boring records, and the geotechnical recommendations needed to aid in the design and construction of foundations, pavement and other earth connected phases of this project are attached. The subsurface soils generally consisted of lean clay with sand, sandy lean clay with gravel and silty sand with gravel. The information obtained by the results of field exploration and laboratory testing indicate the clay soils at anticipated foundation bearing depths have low to moderate expansive potential and moderate load bearing capability. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend the proposed buildings be supported on spread footing and/or grade beam foundation systems. Slab -on -grade may be utilized for the interior floor system provided that care is taken in the placement and compaction of the subgrade soil. Other design and construction details, based upon geotechnical conditions, are presented in the report. Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers Arizona ■ Arkansas ■ Colorado ■ Idaho ■ Illinois ■ Iowa ■ Kansas ■ Minnesota Missouri ■ Montana ■ Nebraska ■ Nevada ■ Oklahoma ■ Texas ■ Utah ■ Wyoming OUALITY ENGINEERING SINCE 1965 GEOTECHNICAL ENGINEERING REPORT BRIDGEFIELD P.U.D., PHASES I AND II WEST PROSPECT ROAD FORT COLLINS, COLORADO ELI PROJECT NO. 20955007 February 8, 1995 Prepared for. LAGUNITAS COMPANY 3307 SOUTH COLLEGE AVENUE, SUITE 200 FORT COLLINS, CO 80525 ATTN: MR. JOHN PROUTY Prepared by. Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. February 7, 1995 Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. GEOTECHNICAL ENGINEERING REPORT BRIDGEFIELD P.U.D., PHASES I AND 11 WEST PROSPECT ROAD FORT COLLINS, COLORADO ELI PROJECT NO. 20955007 February 8, 1995 A Division of The Terracon Companies, Inc.