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Home My WebLink AboutSTONERIDGE PUD, SECOND FILING PRELIMINARY AND FINAL - 21 92E - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTREPORT OF A PAVEMENT DESIGN FOR STONE RIDGE VILLAGE P.U.D. PHASE II FORT COLLINS, COLORADO A Division of The Terracon Companies, Inc. i Terracon Stripping, grubbing, subgrade preparation, and fill and backfill placement should be accomplished under the continuous observation of the geotechnical engineer. Field density tests should be taken daily in the compacted subgrade, fill and backfill under the direction of the geotechnical engineer. Laboratory resistivity tests, pH, oxidation-reduction potential and sulfide tests performed in the laboratory indicate the subsoils at the site are noncorrosive, and protection of metal utility pipe will not, in our opinion, be required. Flexible Pavement It is our opinion flexible pavement is suitable for the proposed street construction at the site. A flexible pavement alternate:should consist of asphalt concrete underlain by crushed aggregate base course and subbase or asphalt concrete underlain by plant mix bituminous base course. The design criteria described below will be utilized in determining the pavement thicknesses at the site. All soils data needed for pavement design has been provided and is included in this report. When traffic data becomes available, pavement sections for Graystone Court will be provided. City of Fort Collins "Design Criteria and Standards for Streets" dated July 1986 and AASHTO Guide for Design of Pavement Structures 1986 18 kip ESAL - 36,500 based on an 18 kip EDLA of 5 for residential streets Resilient Modulus MR of 3775 psi based on an "R" value of 5 Reliability Factor - 70 Overall Deviation - .44 Initial Serviceability Index - 4.5 Terminal Serviceability Index - 2.0 Drainage Coefficient - 1 Qi. f! Terracon 20-Year Design Life Structural Number - 2.24 Strength Coefficients: Asphalt Concrete - 0.44 Plant Mix Bituminous Base Course - 0.34 Crushed Aggregate Base Course - 0.11 Select Subbase - 0.10 The following minimum pavement thicknesses are recommended for Jewelstone, Rosestone and Jadestone Courts: Asphalt Concrete 3" Crushed Aggregate Base Course 8" Total Pavement Thickness 11" Asphalt Concrete 2" Plant Mix Bituminous Base Course 4" Total Pavement Thickness 6" The select subbase should meet City of Fort Collins Class 1 specifications, and the crushed aggregate base course should meet City of Fort Collins Class 5 or 6 specifications. The subgrade below the proposed asphalt pavement should be prepared in accordance with the recommendations discussed in the "Site Grading, Excavation and Utilities" section of this report. Upon proper preparation of the subgrade, the subbase and base course should be placed and compacted between optimum moisture and two percent (2%) wet of optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) It is recommended the asphalt concrete and/or plant mix bituminous base course be placed in two (2) to three (3) inch lifts. All plant mix bituminous base course and asphalt concrete shall meet City of Fort Collins specifications and shall be placed -7- Terracon in accordance with these specifications. All subbase material shall have an "R" value between 50 and 69, the crushed aggregate base course shall have an "R" value between 70 and 77, the plant mix bituminous base course shall have an Rt value of 90 or greater, and the asphalt concrete shall have an Rt value of 95 or greater. The "R" value of the pavement materials used should be verified by laboratory tests. Field density test results should be taken in the aggregate base course, bituminous base course and asphalt concrete under the direction of the geotechnical engineer. Rigid Pavement A feasible foundation alternate at the site would be rigid pavement. Using the 18 kip equivalent daily load application described above, a modulus of subgrade reaction of one hundred (100) pounds per square inch per inch based on an "R" value of 5, a design life of 20 years, and concrete designed with a modulus of rupture of six hundred fifty (650) pounds per square inch, the following minimum pavement thicknesses are recommended: Jewelstone, Rosestone, and Jadestone Courts Nonreinforced Concrete - 6" Subgrade below proposed streets should be prepared in accordance with the recommendations discussed in the "Site Grading, Excavation and Utilities" section of this report. Concrete pavement should be placed directly on the subgrade that has been uniformly and properly prepared in accordance with the above recommendations. All concrete used in the paving shall meet ASTM specifications, and all aggregate shall conform to ASTM C 33 specifications. The concrete should be designed with a minimum modulus of rupture of six hundred fifty (650) pounds per square inch in twenty-eight (28) days. It is recommended laboratory mix designs be performed to -8- I� Terracon determine the proper proportions of aggregates, cement and water necessary to meet these requirements. It is essential the concrete _ have a low water -cement ratio, an adequate cement factor, and sufficient quantities of entrained air. Joints should be carefully designed and constructed in accordance with City of Fort Collins j "Design Criteria and Standards for Streets" specifications to I� ensure good performance of the pavement. It is recommended all concrete pavement be placed in accordance with City of Fort Collins and/or Colorado Department of Transportation specifications. If paving is done during cold weather, acceptable cold weather procedures as outlined in the City of Fort Collins specifications should be utilized. The concrete pavement should be properly cured and protected in accordance with the above specifications. Concrete injured by frost should be removed and replaced. It is i recommended the pavement not be opened to traffic until a flexural I� strength of 400 pounds per square inch is obtained or a minimum of 14 days after the concrete has been placed. GENERAL COMMENTS This report has been prepared for the exclusive use of our client 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. This report has been prepared to aid in the evaluation of the street grades and to assist the engineer in the design of this project. In the event that any changes in the design of the street 1 grades or their locations are planned, the conclusions and recommendations contained in this report will not be considered valid unless said changes are reviewed and conclusions of this report modified or approved in writing by Empire Laboratories, Inc., the geotechnical engineer of record. Terracon Every effort was made to provide comprehensive site coverage through careful locations of the test borings, while keeping the site investigation economically viable. Variations in soil and ground water conditions between test borings may be encountered during construction. In order to permit correlation between the reported subsurface conditions and the actual conditions encountered during construction and to aid in carrying out the plans and specifications as originally contemplated, it is recommended that Empire Laboratories, Inc. be retained to perform continuous construction review during the excavation and foundation phases of the work. Empire Laboratories, Inc. assumes no responsibility for compliance with the recommendations included in this report unless they have been retained to perform adequate on - site construction review during the course of construction. I —10— TEST BORING LOCATION PLAN g5?-F4::7�I E � ► r:: nHA�5 i L4Co L 41 L45 Ld$ n1 L44 L4 or IL43- L5� I L5v L55 L5q L53 L52 L51 L 57 1 L5g LDS L5�► �—� Ltcco Lxo7 L&3 L 400 Loos UoI L�2 L78 w i t„ L 77 L 70 L71 LSo, La L74o L82 0.2 �v5E5-�arl6 c-� 05 L72 I L86 4 L83 L74- L73 I A �) LJU/aL•� I'�Zar�i �u A-2 EMPIRE LABORATORIES, INC. _ R UN REPORT OF A PAVEMENT DESIGN FOR STONE RIDGE VILLAGE P.U.D. PHASE II FORT COLLINS, COLORADO THE KAPLAN COMPANY FORT COLLINS, COLORADO PROJECT NO. 2093-5030 EMPIRE LABORATORIES, INC. A DIVISION OF THE TERRACON COMPANIES INC. 301 NORTH HOWES STREET FORT COLLINS, COLORADO 80521 TABLE OF CONTENTS Table of Contents ................................. i Letter of Transmittal ............................. Report ............................................ 1 Appendix A ........................................ A-1 Test Boring Location Plan A-2 Key to Boring Logs ........................... A-3 Log of Borings .................................. A-4 Appendix B........................................ B-1 Hveem Stabilometer Data ......................... B-2 Summary of Test Results ......................... B-3 AppendixC........................................ C-1 i Empire Laboratories, Inc. A Division of The Terracon Companies, Inc. P.O. Box 503 • 301 No. Howes Fort Collins, Colorado 80522 (303) 484-0359 FAX No. (303) 484-0454 February 26, 1993 The Kaplan Company, Inc. 1060 Sailors Reef Fort Collins, Colorado 80525 Attention: Mr. Les Kaplan Gentlemen: We are pleased to submit our Report of a Pavement Design prepared for the proposed streets for Phase II of Stone Ridge Village located on Horsetooth Road in east Fort Collins, Colorado. The accompanying report presents our findings in the subsurface and our recommendations for pavement design based upon these findings. Very truly yours, EMPIRE LABORATORIES, INC. �' ` 75 `0' ` ALPv 8 'LPL 0 ��) Neil R. errod Senior Engineering Geologist Reviewed by: TER S?„ ice• P Hoag; Chester C. Smith, P.E. - 1:6 o 0ZZ Division Manager o 412r3 cic cc: RBD, Inc. - Mr. Stan Meyers Offices of The Terracon Companies, Inc. 1 i Geotechnical, Environmental and Materials Engineers Arizona: Tucson ■ Colorado: Colorado Springs, Denver, Ft. Collins, Greeley, Longmont ■ Idaho: Boise Illinois: Bloomington, Chicago, Rock Island ■ Iowa: Cedar Falls, Cedar Rapids, Davenport, Des Moines, Storm Lake Kansas: Lenexa, Topeka. Wichita ■ Minnesota: St. Paul ■ Missouri: Kansas City ■ Nebraska: Lincoln, Omaha Oklahoma: Oklahoma City, Tulsa ■ Texas: Dallas ■ Utah: Salt Lake City ■ Wyoming: Cheyenne QUALITY ENGINEERING SINCE 1965 REPORT OF A PAVEMENT DESIGN SCOPE Terracon This report presents the results of a pavement design prepared for the proposed streets located in Stone Ridge Village Phase II in east Fort Collins, Colorado. The scope of the project included test borings and laboratory testing of samples obtained from these borings. The objectives of this study were to (1) determine the soil and ground water conditions at the site, (2) develop criteria for determining pavement design, and (3) make recommendations regarding pavement types and thicknesses for the proposed streets to be constructed at the site. SITE EXPLORATION The field exploration, carried out on February 19, 1993, consisted of drilling, logging, and sampling four (4) test borings. The test borings were located by Empire Laboratories, Inc. from existing property pins using conventional chaining methods. The locations of the test borings are shown on the Test Boring Location Plan included in Appendix A of this report. Boring logs prepared from field logs are shown in Appendix A. These logs show soils encountered, location of sampling and ground water at the time of the exploration. The borings were advanced with a four -inch diameter, continuous -type, power -flight auger drill. During the drilling operations, a geotechnical engineer from Empire Laboratories, Inc. was present and made continuous observations of the soils encountered. ' -1- Terracon SITE LOCATION AND DESCRIPTION The Phase II portion of the site is located directly north of the Phase I portion of the project on Horsetooth Road in east Fort Collins, Colorado. More particularly, the site is described as Stone Ridge Village P.U.D., Phase II, situate in the Southeast 1/4 of Section 29, Township 7 North, Range 68 West of the Sixth P.M., City of Fort Collins, Larimer County, Colorado. The site consists of fallow farmland which is sparsely vegetated with grass and weeds. The majority of the site has been stripped of topsoil. The area is relatively flat and has minor drainage to the south-southeast. The Phase I portion of the project is located to the south and west. Existing farmland is located to the north and east. LABORATORY TESTS Samples from the test borings were subjected to testing in the laboratory to provide a sound basis for evaluating the physical properties of the soils encountered. Moisture contents, dry unit weights, unconfined compressive strengths, laboratory resistivity, pH, sulfides, oxidation-reduction potential, and the Atterberg limits were determined. A summary of the tests results is included in Appendix B. A Hveem stabilometer test was run to determine the "R" value of representative subgrade material at the site, and a curve showing this data is included in Appendix B. SOIL AND GROUND WATER CONDITIONS The soil profile at the site consists of strata of materials j arranged in different combinations. In order of increasing depths, l they are as follows: no= Terracon (1) Silty Topsoil: The area tested is overlain by a six (6) inch layer of silty topsoil. The topsoil has been penetrated by root growth and organic matter and should not be used as a bearing soil or as a fill and/or backfill material. (2) Lean Clay: A layer of brown lean clay underlies the topsoil and extends to depths of four and one-half (4- 1/2) to six (6) feet below the surface. The clay is moderately plastic, is moist and exhibits low subgrade characteristics. (3) Sandy Lean Clay: A layer of tan to red sandy lean clay underlies the upper clay and extends to the sand with gravel stratum below and/or the depths explored. The lower clay contains varying amounts of sand, traces of gravel, is moist and medium stiff. (4) Sand with Gravel: This stratum was encountered in ( Borings 2 and 3 at depths of twelve (12) to thirteen (13) feet below the surface and extends beyond the depths explored. The sand contains varying amounts of fine to medium gravel, is wet, medium dense and poorly graded. (5) Ground Water: Six days after drilling, free ground water was encountered at the site at depths of eleven (11) to twelve and one-half (12-1/2) feet below the surface. Water levels in this area are subject to change due to seasonal variations and irrigation demands on and adjacent to the site. -3- Terracon RECOMMENDATIONS AND DISCUSSION It is our understanding that Jewelstone, Rosestone and Jadestone are residential streets ending in cul-de-sacs. Graystone Court will extend through the project area to a future development to the north. At the time of the site exploration, traffic data for Graystone Court was not available. However, the other streets are considered to be local residential streets. We further understand that minor amounts of cut and fill are proposed, and an underdrain system will be constructed in the Istreets below the proposed sewer. The drainage system will connect to the existing drainage system below Fieldstone Drive. The drainage system should be properly designed and approved by the City of Fort Collins. Site Grading Excavation and Utilities It is recommended the upper six (6) inches of topsoil encountered at the site be stripped and stockpiled for reuse in planted areas. The upper six (6) inches of the natural subgrade below should be scarified and recompacted between optimum moisture and two percent (2%) wet of optimum moisture to at least ninety- five percent (95%) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) All fill should consist of the on -site soils or imported material having an "R" value greater than 5, and this material should be approved by the geotechnical engineer. Fill placed at the site should be placed in uniform six (6) to eight (8) inch lifts and compacted between optimum moisture and two percent (2%) wet of optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698-78. The finished subgrade in cut sections below streets should be scarified a minimum of six (6) inches and recompacted between optimum moisture and two percent -4- r L' I` � Terracon t (2%) wet of optimum moisture to at least ninety-five percent (95%) li of Standard Proctor Density ASTM D 698-78. Finished subgrade below all pavement should be placed a minimum of three (3) feet above existing ground water, or the area should be dewatered to allow for a minimum of three (3) feet between the ground water and the I� pavement subgrade. In areas where subgrade compaction cannot be met due to wet or unstable conditions, the subgrade should be Ii stabilized by use of granular pit run or by geotextiles, lime, fly ash, kiln dust or by other suitable means. All excavations should be dug on safe and stable slopes. The slope of the sides of the excavations should comply with local codes or OSHA regulations. Where this is not practical, sheeting, shoring and/or bracing of the excavation will be required. The sheeting, shoring and bracing of the excavation should be done to prevent sliding or caving of the excavation walls and to protect construction workers and adjacent structures. The side slopes of the excavation or sheeting, shoring or bracing should be maintained under safe conditions until completion of backfilling. In addition, heavy construction equipment should be kept a safe distance from the edge of the excavation. Where utilities are excavated below ground water, dewatering will be needed during placement of pipe and backfilling for proper construction. All piping should be adequately bedded for proper load distribution. Backfill placed in utility trenches in open and planted areas should be compacted in uniform lifts between optimum moisture and two percent (2%) wet of optimum moisture to at least ninety percent (90%) of Standard Proctor Density ASTM D 698-78 the full depth of the trench. Backfill placed in utility trenches under roadways and paved areas should be compacted between optimum moisture and two percent (2%) wet of optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698- 78. -5-