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Home My WebLink AboutHOMESTEAD PUD SECOND - Filed SER-SUBSURFACE EXPLORATION REPORT - (2)111 SUBSURFACE EXPLORATION REPORT HOMESTEAD HEIGHTS PAVEMENTS FORT COLLINS, COLORADO EEC PROJECT NO. 1034086P EEC EARTH ENGINEERING CONSULTANTS, INC. III II E EC 11 April 23, 2004 EARTH ENGINEERING CONSULTANTS, INC. 4 Splittgerber Professional Builders P.O. Box 271307 111 Fort Collins, Colorado 80527-1307 111 Attn: Mr. Rick Splittgerber Re: Pavement Design II Homestead Heights Fort Collins, Colorado EEC Project No. 1034086P UMr. Splittgerber: 111 Enclosed,herewith,are the results of the geotechnical subsurface exploration completed by Earth Engineering Consultants,Inc.personnel for Hearthside Drive,Old Legacy Drive,Old Dominion Court and Fireside Court in the Homestead Heights development in Fort Collins. IIThe structural pavement design for the roadways will be completed after we receive traffic load information from the City of Fort Collins Engineering Department. IllWe appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed report, or if we can be of further service to you in any Uother way,please do not hesitate to contact us. Very truly yours, 1111 Earth Engineering Consultants,Inc. Reviewed by:p0 RCS/•' F, sj: 0 REBih.NON 6 .'cc' p-^ t..110i il4 ,, OM II Wolf von car owitz, P.E. Les e' Litton, P.E. Senior Project Engineer Principal Engineer 111 cc: Rick Richter- City of Fort Collins (4) IICENTRE FOR ADVANCED TECHNOLOGY 230 I RESEARCH BOULEVARD, SUITE 104 U FORT COLLINS, COLORADO 80526 970) 224-1522 (FAx) 224-4564 U SUBSURFACE EXPLORATION REPORT HOMESTEAD HEIGHTS PAVEMENTS FORT COLLINS, COLORADO EEC PROJECT NO. 1034086P U April 23, 2004 111 INTRODUCTION The subsurface exploration for a portion of the roadways in the Homestead Heights U development located southwest of the intersection of Ziegler and Kechter Roads in Fort Collins, Colorado has been completed. Ten (10) soil borings were advanced in the right- of-way of the new streets to develop information on existing subsurface conditions. At the time of our exploration, the sanitary sewer and water line had been installed in the roadway right-of-way. Individual boring logs and a diagram indicating the approximate boring locations are included with this report. The roadways evaluated include Hearthside Drive, Old Legacy Drive, Old Dominion Court and Fireside Court located in southeast Fort Collins. The location of referenced roadways is indicated on the attached location diagram. At the time of our exploration, the street subgrade was at approximate final grade and the sanitary sewer and water utilities had been installed in the street right-of-ways. The purpose of our exploration was to define the existing subsurface conditions in the referenced streets for use in the pavement structure design. EXPLORATION AND TESTING PROCEDURES The boring locations were selected'and established in the field by Earth Engineering Consultants, Inc. (EEC) personnel. In accordance with current City of Fort Collins requirements, two (2) soil borings were advanced at each of five (5) test areas. One of the Iborings at each test location was advanced through the utility trench backfill to a depth of approximately 5 feet below present grade. A second boring was advanced to a depth of Iapproximately 10 feet below surface grade at each test location outside the utility backfill U N Earth Engineering Consultants,Inc. EEC Project No. 1034086P April 23, 2004 Page 2 area. The boringlocations were selected and established in the field byEarth Engineeringgg Consultants, Inc. (EEC)personnel. The field locations were established by approximating locations relative to identifiable site features. The locations of the field borings should be considered accurate only to the degree implied by the methods used to make the field measurements. The borings were performed with a CME-45 drill rig using 4-inch nominal diameter continuous flight augers. Samples of the subgrade materials were obtained in general accordance with split-barrel and California barrel sampling procedures (ASTM Specification D-1586) and from the auger cuttings. Subsurface samples were also obtained by pushing thin-walled"Shelby"tubes in general accordance with ASTM Specification D- 1587. All samples were sealed and returned to our Fort Collins laboratory for further classification and testing. N Moisture content tests were completed in the laboratory on each of the recovered samples. Washed sieve analysis and Atterberg limits tests were performed on selected samples to help evaluate the quantity and plasticity of fines in the subgrade soils. Swell/consolidation tests were performed on selected samples to help evaluate subgrade volume change characteristics. As a 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 shown on the boring logs and a brief 1111 description of that classification system is included with this report. 111 SITE AND SUBSURFACE CONDITIONS Based on the results of our subsurface exploration and laboratory testing, subsurface conditions can be generalized as follows. The subgrade soils encountered in the test borings generally consisted of brown lean clay with varying amounts of silt and sand sized U U Earth Engineering Consultants,Inc. EEC Project No. 1034086P April 23, 2004 Page 3 Uparticles. A portion of material encountered in the test borings was utility backfill. The site materials are slightly to moderately plastic as indicated from the Atterberg limits tests. 111 The lean clay soils showed low swell potential in their in-situ moisture and density conditions. The subsurface soils have low remolded strength. Bedrock was not 11 encountered in any of the borings completed for this project. The lean clay encountered extended to the depth explored of approximately 5 to 10 feet below ground surface. The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil types; in-situ, the transition of materials may be gradual and indistinct. Observations were made while drilling and after completion of the borings to detect the presence and depth to free water. Free water was not observed in any of the completed borings at the time of drilling. 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. Zones of perched and/or trapped water may be encountered at times throughout the year in more permeable zones in the subgrade materials. Perched water is commonly encountered in soils overlying less permeable bedrock. 111 ANALYSIS AND RECOMMENDATIONS The subgrades for the roadway have been prepared in general accordance with City of Fort Collins criteria. The sewer and water utilities have been installed within the roadway right-of-way in accordance with City requirements. Field density tests have been completed on the utility backfill materials within the roadway area. The test results indicate the site fill and backfill materials were compacted to at least 95% of standard Proctor maximum dry density. U U U U Earth Engineering Consultants,Inc. EEC Project No. 1034086P April 23, 2004 Page 4 The subgrade soils in the roadway areas generally consist of lean clay with low potential. At current moisture and density conditions, we expect the roadway subgrades could be 111 used for direct support of a composite asphalt/aggregate base pavement structure as required by the City of Fort Collins. Care will be needed to insure pavement subgrades are not disturbed prior to paving. Structural pavement design for the roadways will be completed after we receive traffic load information from the City of Fort Collins Engineering Department. 011 An R-value less than 5 was estimated for the pavement subgrades. A Hveem stabilometer R-value of 5 will be used in the pavement design for the rough graded pavement subgrades. 1111 GENERAL COMMENTS 1 The preliminary analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations which may occur between borings or across the site. The nature and extent of such variations may not become evident until further exploration or construction. If variations appear evident, it 111 will be necessary to re-evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so that comments can be made regarding the interpretation and implementation of our geotechnical recommendations in the design and specifications. It is 111 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. U U U U Earth Engineering Consultants,Inc. EEC Project No. 1034086P April 23, 2004 Page 5 This report has been prepared for the exclusive use of Splittgerber Professional Builders 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 111 this report modified or verified in writing by the geotechnical engineer. 11 U U U U U U U U U U