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HomeMy WebLinkAboutTIMBERLINE INTERNATIONAL MIXED USE - PDP200007 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT400 North Link Lane | Fort Collins, Colorado 80524 Telephone: 970-206-9455 Fax: 970-206-9441 SUBGRADE INVESTIGATION LOT 1, INDUSTRIAL BUSINESS PARK TIMBERLINE ROAD AND INTERNATIONAL BOULEVARD FORT COLLINS, COLORADO Prepared For: Architecture West, LLC 5833 Big Canyon Drive Fort Collins, Colorado 80528 Attention: Steve Steinbicker Project No. FC08517-135 November 4, 2019 TABLE OF CONTENTS SCOPE 1 SUMMARY OF CONCLUSIONS 1 SITE LOCATION AND PROJECT DESCRIPTION 2 FIELD AND LABORATORY INVESTIGATION 2 PAVEMENT DESIGN 3 Traffic Projections 4 Subgrade and Groundwater Conditions 4 Pavement Thickness Calculations 5 Pavement Recommendations 5 PAVEMENT SELECTION 6 SUBGRADE AND PAVEMENT MATERIALS AND CONSTRUCTION 6 WATER-SOLUBLE SULFATES 8 MAINTENANCE 9 SURFACE DRAINAGE 9 LIMITATIONS 10 FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX A – RESULTS OF LABORATORY TESTING APPENDIX B – PAVEMENT DESIGN CALCULATIONS APPENDIX C – SAMPLE SITE GRADING SPECIFICATIONS APPENDIX D – PAVEMENT CONSTRUCTION RECOMMENDATIONS APPENDIX E – MAINTENANCE PROGRAM ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 1 SCOPE This report presents the results of our Subgrade Investigation and Pavement Recommendations for the proposed widening of a segment of Timberline Road in Fort Collins, Colorado. The purpose of our subgrade investigation was to determine the subsurface conditions and to evaluate pavement support characteristics for our pavement recommendations. The report was conducted in general conformance with the Chapters 5 and 10 of the Larimer County Urban Areas Street Standards (LCUASS) dated January 2, 2001 (repealed and reenacted April 1, 2007) as adopted by the City of Fort Collins (City). This report was prepared from data developed during field exploration, laboratory testing, engineering analysis, and experience with similar conditions. The report includes a description of the subsurface conditions found in exploratory borings, laboratory test results, and pavement construction and material recommendations for the widening of part of Timberline Road. If plans change significantly, we should be contacted to review our investigation and determine if our recommendations still apply. A brief summary of our conclusions is presented below, with more detailed criteria and recommendations contained in the report. SUMMARY OF CONCLUSIONS 1. Soils encountered in our borings were variable and consisted of 0 to 4 feet of fill over clayey sand to the depths explored. Groundwater was not encountered in the borings during drilling. Existing groundwater levels are not expected to affect the proposed construction. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 2 2. Soils encountered in our boring are generally considered to exhibit fair to good subgrade support characteristics based on classification tests. Field penetration tests indicate the soil is loose to dense and may require stabilization prior to placing pavement materials. 3. Our laboratory tests indicate the subgrade soils have a low to moderate expansion potential and mitigation for swell of the subgrade soils will be required. We recommend over-excavation of the existing subgrade to a depth of 2 feet below the final subgrade surface elevation. 4. Hot mix asphalt over aggregate base course and Portland cement concrete are appropriate surface pavements. Minimum pavement recommendations are presented in this report. SITE LOCATION AND PROJECT DESCRIPTION The subject project is located in a developed area east of downtown Fort Collins on the plains of Colorado. At the time of our investigation, grading had not begun. Ground cover consists of native grasses, garbage and trees. The site varies in topography with a general slope to the west. An irrigation ditch flows southeast, passing underneath the intersection of International Boulevard and Timberline Road. We understand the proposed construction includes widening of Timberline Road from International Boulevard, north approximately 400 feet to service a proposed neighboring development at Lot 1, Industrial Business Park, located at the northwest corner of the intersection of Timberline Road and International Boulevard. FIELD AND LABORATORY INVESTIGATION Subsurface conditions at the site were investigated by drilling two borings in the proposed roadway alignment. The approximate locations of the borings are shown on Figure 1. Our field representative observed drilling, logged the ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 3 soils found in the borings and obtained samples. Summary logs of the borings, including results of field penetration resistance tests, are presented on Figure 2. Samples obtained during drilling were returned to our laboratory and examined by the geotechnical engineer for this project. Laboratory testing included natural moisture content, dry density, gradation analyses, swell- consolidation, Atterberg Limits, water-soluble sulfates, and Hveem Stabilometer test. Laboratory testing was performed in general accordance with AASHTO and ASTM methods to determine index properties, classification, and subgrade support values for those soil types influencing the pavement design. To evaluate potential heave, swell-consolidation testing was performed on samples of the subgrade soils under a pressure of 150 pounds per square foot (psf) as required under LCUASS. Results of laboratory tests are presented in Appendix A and summarized on Table A-I. SUBSURFACE CONDITIONS Subsurface conditions encountered in our borings consisted of 0 to 4 feet of clayey sand with gravel fill over clayey sand with slight gravel fractions to the depths explored. Groundwater was not encountered in the borings. Graphic logs of the borings are presented on Figure 2. Based on our laboratory testing, the native and fill materials classify as A-6 or A-2-4 Soils in accordance with AASHTO procedures. A Hveem Stabilometer test was performed on a composite sample of the fill and native materials, resulting in an R-value of 47. PAVEMENT DESIGN New construction is planned for the widening of Timberline Road. We understand improvements to Timberline Road are regulated by the City, which requires the use of the AASHTO and CDOT pavement design methods for their roadways. These design methods require input parameters for traffic projections ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 4 for a specified design life, roadway classification, characteristics of the subgrade materials, type and strength characteristics of pavement materials, groundwater conditions, drainage conditions, minimum pavement sections, and statistical data. Traffic Projections The traffic projections are based on vehicle loading, traffic volume, design period, and growth factor. Traffic projections are expressed as an 18-kip Equivalent Daily Load Application (EDLA) for a single day and as an 18-kip Equivalent Single Axle Load (ESAL) for the design period, which is typically 20 years. An ESAL of 1,460,000 for Timberline Road was provided by City personnel using a 20-year design life. Subgrade and Groundwater Conditions The subgrade soils consist of sandy clay that classifies as A-6 or A-2-4 in accordance with AASHTO classification methods. A Hveem stabilometer test of a composite sample of the subgrade soil resulted in an R-value of 47, which we converted to a resilient modulus of 11,749 psi based on CDOT criteria. For rigid pavement design, we estimated a modulus of subgrade reaction (k-value) of 150 psi/in based on soil classification and standard penetration tests. Swell tests indicate the subgrade soils have a low to medium expansion potential. LCUASS requires swell mitigation where swell is 2 percent or greater. Based on the results of laboratory testing and LCUASS, we believe that mitigation for swell will be required. Groundwater was not encountered in the borings. Groundwater located at least 5 feet below the subgrade surface is not expected to interfere with the performance of the pavement. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 5 Pavement Thickness Calculations We used AASHTO methods to develop our pavement thickness calculations for both flexible and rigid pavements with input values provided by the City, LCUASS, and our laboratory tests and observations. For our design, we assumed the pavement will be constructed during a single stage. Input values including initial and terminal serviceability indices, reliability factor, layer strength coefficients, and minimum sections were provided by LCUASS for Timberline Road, which is classified as a four-lane arterial. Other input values not specified by LCUASS were estimated based on our experience with similar projects. Computer generated printouts of the pavement calculations are presented in Appendix B. Pavement Recommendations For our design, we assume the pavement will be constructed during a single stage. If multiple-stage construction is desired, we should be consulted to revise our recommendations. Our pavement thickness calculations did not include credit towards chemically treated subgrade soils or the design of a soil/fly ash mixture. If plans change, we are available to perform a soil/fly ash mix design. We have provided pavement design alternatives for new construction including hot mix asphalt (HMA) on aggregate base course (ABC), and Portland cement concrete (PCC) pavement. Our pavement thickness alternatives are presented on Table A. Additional discussion regarding advantages and disadvantages of the pavement alternatives and their expected performance is included under the PAVEMENT SELECTION section of this report. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 6 TABLE A MINIMUM PAVEMENT THICKNESS RECOMMENDATIONS Roadway Hot Mix Asphalt (HMA) + Aggregate Base Course (ABC)+ Moisture Treated Subgrade (MTS) Portland Cement Concrete (PCC) + Moisture Treated Subgrade (MTS) Timberline Road ESAL = 1,460,000 8” HMA + 6” ABC+ 24” MTS 8.5” PCC+ 24” MTS PAVEMENT SELECTION Both HMA/ABC composite (flexible) and PCC (rigid) pavements are expected to perform well for the roadways. However, PCC pavement has better performance in freeze-thaw conditions and should require less long-term maintenance than HMA pavement. PCC pavement is also recommended for sections that may experience frequent stopping and turning, heavy point loads, or chemical spills. SUBGRADE AND PAVEMENT MATERIALS AND CONSTRUCTION The construction materials are assumed to possess sufficient quality as reflected by the strength factors used in our design calculations. Materials and construction requirements of LCUASS should be followed. Subgrade preparation will only apply to areas planned for new construction. Our laboratory tests indicate the subgrade soils have an expansion potential ranging from 0.7 to 2.4 percent. LCUASS requires mitigation for subgrade soils that swell 2 percent or greater. Based on these conditions, we believe the subgrade soils will require mitigation for swell. We recommend over- excavation of the top 2 feet of subgrade soils. To prepare the subgrade for ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 7 paving with conventional moisture treatment and compaction, the over-excavated soils should be moisture conditioned to 1 to 3 percent above optimum for swell mitigation and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T99). Recommendations for conventional moisture treatment and compaction are presented in Appendix D. Preparation of the subgrade should extend from back-of walk to back-of-walk where feasible. Recompaction of the upper subgrade soils should occur as close to the time of pavement construction as possible. The final subgrade surface must be protected from excessive drying or wetting until such time as the pavement section is constructed. Maintaining moisture contents near optimum will be critical to avoid excessive deflections, rutting and pumping of the subgrade during subgrade preparation of streets. If moisture and density cannot be sufficiently controlled during subgrade preparation and stabilization is required, chemical stabilization, stabilization by removal and replacement, or stabilization using geotextiles and imported granular materials may be used. For isolated or small areas requiring stabilization, removal and replacement or “crowding” crushed, coarse aggregate into the subgrade may be effective. If large areas require stabilization, chemical treatment of the soils may be a more effective alternative. These criteria were developed from analysis of the field and laboratory data, our experience and LCUASS requirements. If the materials cannot meet these requirements, our pavement recommendations should be re-evaluated based upon available materials. The use of recycled materials, such as recycled asphalt pavement (RAP) and recycled concrete may be used in place of aggregate base course provided they meet minimum R-values and gradations established by LCUASS and CDOT. Materials planned for construction should ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 8 be submitted and the applicable laboratory tests performed to verify compliance with the specifications. WATER-SOLUBLE SULFATES Concrete that comes into contact with soils can be subject to sulfate attack. We measured water-soluble sulfate concentrations in two samples from this site. Concentrations were measured at 0.03 and 0.48 percent. Water- soluble sulfate concentrations between 0.2 and 2 percent indicate Class 2 exposure to sulfate attack for concrete that comes into contact with the soil, according to the American Concrete Institute (ACI). For sites with Class 2 sulfate exposure, ACI recommends using a cement meeting the requirements for Type V (sulfate resistant) cement or the equivalent, with a maximum water-to- cementitious material ratio of 0.45 and air entrainment of 5 to 7 percent. As an alternative, ACI allows the use of cement that conforms to ASTM C 150 Type II requirements, if it meets the Type V performance requirements (ASTM C 1012) of ACI 201, or ACI allows a blend of any type of portland cement and fly ash that meets the performance requirements (ASTM C 1012) of ACI 201. In Colorado, Type II cement with 20 percent Class F fly ash usually meets these performance requirements. The fly ash content can be reduced to 15 percent for placement in cold weather months, provided a water-to-cementitious material ratio of 0.45 or less is maintained. ACI also indicates concrete with Class 2 sulfate exposure should have a minimum compressive strength of 4500 psi. Concrete should be air entrained. Sulfate attack problems are comparatively rare in this area when quality concrete is used. Considering the range of test results, we believe risk of sulfate attack is lower than indicated by the few laboratory tests performed. The risk is also lowered to some extent by damp-proofing the surfaces of concrete walls in contact with the soil. ACI indicates sulfate resistance for Class 1 exposure can be achieved by using Type II cement, a maximum water-to-cementitious material ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 9 ratio of 0.50, and a minimum compressive strength of 4000 psi. We believe this approach should be used as a minimum at this project. The more stringent measures outlined in the previous paragraph will better control risk of sulfate attack and are more in alignment with written industry standards. MAINTENANCE Routine maintenance, such as sealing and repair of cracks, is necessary to achieve the long-term life of a pavement system. We recommend a preventive maintenance program be developed and followed for all pavement systems to assure the design life can be realized. Choosing to defer maintenance usually results in accelerated deterioration leading to higher future maintenance costs, and/or repair. A recommended maintenance program is outlined in Appendix E. Excavation of completed pavement for utility construction or repair can destroy the integrity of the pavement and result in a severe decrease in serviceability. To restore the pavement top original serviceability, careful backfill compaction before repaving is necessary. SURFACE DRAINAGE A primary cause of premature pavement deterioration is infiltration of water into the pavement system. This increase in moisture content usually results in the softening of base course and subgrade soil and eventual failure of the pavement. In addition, parts of Colorado experience many freeze-thaw cycles each season that can result in deterioration of the pavement. We recommend that subgrade, pavement, and surrounding ground surface be sloped to cause surface water to run off rapidly and away from pavements. Backs of curbs and gutters should be backfilled with compacted fill and sloped to prevent ponding ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 10 adjacent to backs of curbs and to paving. The final grading of the subgrade should be carefully controlled so the pavement design cross-section can be maintained. Low spots in the subgrade that can trap water should be eliminated. Seals should be provided within the curb and pavement and in all joints to reduce the possibility of water infiltration. LIMITATIONS This report has been prepared for the exclusive use of Architecture West, LLC for the purpose of providing geotechnical design and construction criteria for the proposed project. This report was prepared from data developed during our field exploration, laboratory testing, engineering analysis, and experience with similar conditions. The borings were spaced to obtain a reasonably accurate understanding of the subsurface conditions. The borings are representative of conditions encountered only at the exact boring locations. Variations in subsurface conditions not indicated by our borings are always possible. The recommendations contained in this report were based upon our understanding of the planned construction. If plans change or differ from the assumptions presented herein, we should be contacted to review our recommendations. A representative of our firm should observe subgrade preparation and pavement construction. Our representative should also conduct tests of construction materials for compliance with recommendations presented in this report and/or specifications of the controlling agency. Due to the changing nature of site characterization, pavement design methods, standards, and practices, the information and recommendations provided in this report are only valid for one year following the date of issue. Following that time, our office should be contacted to provide, if necessary, any ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 11 updated recommendations and design criteria as appropriate for the engineering methodologies used at that time. We believe this investigation was conducted in a manner consistent with that level of skill and care ordinarily used by members of the profession currently practicing under similar conditions in the locality of this project. No warranty, express or implied, is made. If we can be of further service in discussing the contents of this report or in the analysis of the influence of subsurface conditions on design of the pavements, please call. CTL | THOMPSON, INC. by: Taylor H. Ray, EIT Spencer Schram, PE Staff Geotechnical Engineer Geotechnical Department Manager THR:SAS Via e-mail: steve@architecturewestllc.com International Boulevard Timberline Road TH-2 TH-1 E. VINE DR. TIMBERLINE RD. INTERNATIONAL BLVD. E. LINCOLN AVE. E. MULBERRY ST. SITE LEGEND: INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING TH-1 ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL I T PROJECT NO. FC08517-135 FIGURE 1 Locations of Exploratory Borings VICINITY MAP (FORT COLLINS, COLORADO) NOT TO SCALE 40' 80' APPROXIMATE SCALE: 1" = 80' 0' 0 5 10 0 5 10 13/12 20/12 35/12 WC=4.6 -200=31 R-VAL=47 WC=3.4 LL=28 PI=10 -200=34 WC=4.2 DD=117 SW=2.4 SS=0.480 WC=4.6 -200=31 WC=3.4 LL=28 PI=10 -200=34 WC=4.2 DD=117 SW=2.4 SS=0.480 TH-1 13/12 8/12 13/12 WC=7.4 DD=119 SW=0.7 WC=16.3 DD=108 LL=35 PI=14 -200=44 WC=7.4 DD=119 SW=0.7 SS=0.030 WC=16.3 DD=108 LL=35 PI=14 -200=44 TH-2 FIGURE 2 SAND, CLAYEY, MOIST, LOOSE TO DENSE, BROWN, TAN (SC) 3. DRIVE SAMPLE. THE SYMBOL 13/12 INDICATES 13 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. SAND, GRAVEL AND CLAY FILL, MOIST, MEDIUM DENSE, BROWN, DARK BROWN BULK SAMPLE FROM AUGER CUTTINGS. LEGEND: WC DD SW -200 APPENDIX A RESULTS OF LABORATORY TESTING Sample of SAND, CLAYEY (SC) DRY UNIT WEIGHT= 117 PCF From TH - 1 AT 4 FEET MOISTURE CONTENT= 4.2 % Sample of FILL, SAND, CLAYEY, SLIGHTLY GRAVELLY (SC) DRY UNIT WEIGHT= 119 PCF From TH - 2 AT 2 FEET MOISTURE CONTENT= 7.4 % ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL | T PROJECT NO. FC08517-135 APPLIED PRESSURE - KSF APPLIED PRESSURE - KSF COMPRESSION % EXPANSION COMPRESSION % EXPANSION -3 -2 -1 0 1 2 3 4 EXPANSUND IONC ER ONS TA NT PRSUDUE ES RE TO W ETT IN G -4 -3 -2 -1 0 1 2 3 EXPANSUND IONC ER ONS TA NT PRDUE ESSURE TO W ETT IN G 0.1 1.0 10 100 0.1 1.0 10 100 FIGURE A-1 Swell Consolidation Sample of SAND, CLAYEY, GRAVELLY (SC) GRAVEL 12 % SAND 57 % From S - 1 AT 0-4 FEET SILT & CLAY 31 % LIQUID LIMIT % PLASTICITY INDEX % Sample of SAND, CLAYEY (SC) GRAVEL 3 % SAND 63 % From TH - 1 AT 2 FEET SILT & CLAY 34 % LIQUID LIMIT 28 % PLASTICITY INDEX 10 % ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL | T PROJECT NO. FC08517-135 Gradation Test Results 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 Sample of SAND, CLAYEY (SC) GRAVEL 5 % SAND 51 % From TH - 2 AT 4 FEET SILT & CLAY 44 % LIQUID LIMIT 35 % PLASTICITY INDEX 14 % Sample of GRAVEL % SAND % From SILT & CLAY % LIQUID LIMIT % PLASTICITY INDEX % ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL | T PROJECT NO. FC08517-135 Gradation Test Results 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 FIGURE A-4 Hveem Stabilometer Test Results ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL|T PROJECT NO. FC08517-135 0 100 200 300 400 500 600 700 800 900 0 10 20 30 40 50 60 70 80 90 0.1 1.0 10 1 "R" VALUE EXUDATION PRESSURE (PSI) Sample Location AASHTO Classification % -200 Liquid Limit Plasticity Index Design R - Value S-1 A-2-4 31 47 PASSING WATER- MOISTURE DRY LIQUID PLASTICITY APPLIED NO. 200 SOLUBLE R- DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE SIEVE SULFATES VALUE BORING (FEET) (%) (PCF) (%) (PSF) (%) (%) DESCRIPTION S-1 0-4 4.6 31 47.0 SAND, CLAYEY, GRAVELLY (SC) TH-1 2 3.4 28 10 34 SAND, CLAYEY (SC) TH-1 4 4.2 117 2.4 150 0.48 SAND, CLAYEY (SC) TH-2 2 7.4 119 0.7 150 0.03 FILL, SAND, CLAYEY, SLIGHTLY GRAVELLY (SC) TH-2 4 16.3 108 35 14 44 SAND, CLAYEY (SC) ATTERBERG LIMITS SWELL TEST RESULTS* Page 1 of 1 * NEGATIVE VALUE INDICATES COMPRESSION. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL|T PROJECT NO. FC08517-135 SUMMARY OF LABORATORY TESTING TABLE A-I APPENDIX B PAVEMENT DESIGN CALCULATIONS Roadway(s): Reliability 95 % Standard Deviation 0.44 Initial Serviceability 4.5 Terminal Serviceability 2.5 Resilient Modulus 11,749 psi Design ESALs 1,460,000 Layers Structural Coefficient Drainage Thickness SN HMA 0.44 1 8 3.52 ABC 0.11 1.05 15 1.73 CSS 0.1 1 0 0.00 SUM 5.25 ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL|T PROJECT NO. FC08517-135 FIGURE B-1 Design Structural Number 3.21 Flexible Structural Design Timberline Road (Native Subgrade) Rigid Pavement Design - Based on AASHTO Supplemental Guide Reference: LTPP DATA ANALYSIS - Phase I: Validation of Guidelines for k-Value Selection and Concrete Pavement Performance Prediction Results Project # FC08517-135 Description: RIGID PAVEMENT DESIGN Location: LOT 1, INDUSTRIAL BUSINESS PARK Slab Thickness Design Pavement Type JPCP 18-kip ESALs Over Initial Performance Period (million) 1.46 million Initial Serviceability 4.5 Terminal Serviceability 2.5 28-day Mean PCC Modulus of Rupture 600 psi Elastic Modulus of Slab 3,400,000 psi Elastic Modulus of Base 1,200 psi Base Thickness in. Mean Effective k-Value 150 psi/in Reliability Level 95 % Overall Standard Deviation 0.44 Calculated Design Thickness* 8.30 in * = Design Thickness should be rounded up to nearest half inch. 8.5" PCC is final design thickness ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL|T PROJECT NO. FC08517-135 FIGURE B-2 APPENDIX C SAMPLE SITE GRADING SPECIFICATIONS ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 C-1 SAMPLE SITE GRADING SPECIFICATIONS 1. DESCRIPTION This item shall consist of the excavation, transportation, placement, and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve site elevations. 2. GENERAL The Soils Engineer shall be the Owner's representative. The Soils Engineer shall approve fill materials, method of placement, moisture contents, and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all trees, brush, and rubbish before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to provide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified to a depth of 8 inches until the surface is free from ruts, hummocks or other uneven features, which would prevent uniform compaction by the equipment to be used. 5. COMPACTING AREA TO BE FILLED After the foundation for the fill has been cleared and scarified, it shall be disked or bladed until it is free from large clods, brought to the proper moisture content and compacted to not less than 95 percent of maximum density as determined in accordance with ASTM D 698. 6. FILL MATERIALS Materials classifying as SC, SM, SW, SP, GP, GC, and GM are acceptable. Fill soils shall be free from organic matter, debris, or other deleterious substances, and shall not contain rocks or lumps having a diameter greater than three (3) inches. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 C-2 7. MOISTURE CONTENT Fill materials shall be moisture treated. Clay soils should be moisture-treated to between optimum and 3 percent above optimum moisture content as determined from Standard Proctor compaction tests. Sand soils should be moistened to within 2 percent optimum moisture content. Sufficient laboratory compaction tests shall be made to determine the optimum moisture content for the various soils encountered in borrow areas. The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The Contractor may be required to rake or disk the fill soils to provide uniform moisture content through the soils. The application of water to embankment materials shall be made with any type of watering equipment approved by the Soils Engineer, which will give the desired results. Water jets from the spreader shall not be directed at the embankment with such force that fill materials are washed out. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling, and all work on that section of the fill shall be delayed until the material has been allowed to uniformly dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum density. Fill materials shall be placed such that the thickness of loose material does not exceed 8 inches and the compacted lift thickness does not exceed 6 inches. Compaction, as specified above, shall be obtained by the use of sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by the Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall be continuous over the entire area. Compaction equipment shall make sufficient trips to insure that the required density is obtained. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 C-3 9. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is no appreciable amount of loose soil on the slopes. Compaction of slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed 3:1 (horizontal to vertical). 10. DENSITY TESTS Field density tests shall be made by the Soils Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate that the density or moisture content of any layer of fill or portion thereof is below that required, the particular layer or portion shall be reworked until the required density or moisture content has been achieved. 11. COMPLETED PRELIMINARY GRADES All areas, both cut and fill, shall be finished to a level surface and shall meet the following limits of construction: A. Overlot cut or fill areas shall be within plus or minus 2/10 of one foot. B. Street grading shall be within plus or minus 1/10 of one foot. The civil engineer, or duly authorized representative, shall check all cut and fill areas to observe that the work is in accordance with the above limits. 12. SUPERVISION AND CONSTRUCTION STAKING Observation by the Soils Engineer shall be continuous during the placement of fill and compaction operations so that he can declare that the fill was placed in general conformance with specifications. All site visits necessary to test the placement of fill and observe compaction operations will be at the expense of the Owner. All construction staking will be provided by the Civil Engineer or his duly authorized representative. Initial and final grading staking shall be at the expense of the owner. The replacement of grade stakes through construction shall be at the expense of the contractor. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 C-4 13. SEASONAL LIMITS No fill material shall be placed, spread or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Soils Engineer indicates that the moisture content and density of previously placed materials are as specified. 14. NOTICE REGARDING START OF GRADING The contractor shall submit notification to the Soils Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in advance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 15. REPORTING OF FIELD DENSITY TESTS Density tests made by the Soils Engineer, as specified under "Density Tests" above, shall be submitted progressively to the Owner. Dry density, moisture content, of each test taken, and percentage compaction shall be reported for each test taken. 16. DECLARATION REGARDING COMPLETED FILL The Soils Engineer shall provide a written declaration stating that the site was filled with acceptable materials, or was placed in general accordance with the specifications. APPENDIX D PAVEMENT CONSTRUCTION RECOMMENDATIONS ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 D-1 SUBGRADE PREPARATION Moisture Treated Subgrade (MTS) 1. The subgrade should be stripped of organic matter, scarified, moisture treated and compacted to the specifications stated below in Item 2. The compacted subgrade should extend at least 3 feet beyond the edge of the pavement where no edge support, such as curb and gutter, are to be constructed. 2. Sandy and gravelly soils (A-1-a, A-1-b, A-3, A-2-4, A-2-5, A-2-6, A- 2-7) should be moisture conditioned near optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Clayey soils (A-6, A-7-5, A-7-6) should be moisture conditioned between optimum and 3 percent above optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 3. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. As a minimum, fill should be compacted to 95 percent of standard Proctor maximum dry density. 4. Final grading of the subgrade should be carefully controlled so the design cross-slope is maintained and low spots in the subgrade that could trap water are eliminated. 5. Once final subgrade elevation has been compacted and tested to compliance and shaped to the required cross-section, the area should be proof-rolled using a minimum axle load of 18 kips per axle. The proof-roll should be performed while moisture contents of the subgrade are still within the recommended limits. Drying of the subgrade prior to proof-roll or paving should be avoided. 6. Areas that are observed by the Engineer that have soft spots in the subgrade, or where deflection is not uniform of soft or wet subgrade shall be ripped, scarified, dried or wetted as necessary and recompacted to the requirements for the density and moisture. As an alternative, those areas may be sub-excavated and replaced with properly compacted structural backfill. Where extensively soft, yielding subgrade is encountered; we recommend a representative of our office observe the excavation. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 D-2 PAVEMENT MATERIALS AND CONSTRUCTION Aggregate Base Course (ABC) 1. A Class 5 or 6 Colorado Department of Transportation (CDOT) specified ABC should be used. Reclaimed asphalt pavement (RAP) or reclaimed concrete pavement (RCP) alternative which meets the Class 5 or 6 designation and design R-value/strength coefficient is also acceptable. 2. Bases should have a minimum Hveem stabilometer value of 78, or greater. ABC, RAP, and RCP must be moisture stable. The change in R-value from 300-psi to 100-psi exudation pressure should be 12 points or less. 3. ABC, RAP or RCP bases should be placed in thin lifts not to exceed 6 inches and moisture treated to near optimum moisture content. Bases should be moisture treated to near optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 4. Placement and compaction of ABC, RAP, or RCP should be observed and tested by a representative of our firm. Placement should not commence until the underlying subgrade is properly prepared and tested. Hot Mix Asphalt (HMA) 1. HMA should be composed of a mixture of aggregate, filler, hydrated lime and asphalt cement. Some mixes may require polymer modified asphalt cement or make use of up to 20 percent reclaimed asphalt pavement (RAP). A job mix design is recommended and periodic checks on the job site should be made to verify compliance with specifications. 2. HMA should be relatively impermeable to moisture and should be designed with crushed aggregates that have a minimum of 80 percent of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 D-3 3. Gradations that approach the maximum density line (within 5 percent between the No. 4 and 50 sieves) should be avoided. A gradation with a nominal maximum size of 1 or 2 inches developed on the fine side of the maximum density line should be used. 4. Total void content, voids in the mineral aggregate (VMA) and voids filled should be considered in the selection of the optimum asphalt cement content. The optimum asphalt content should be selected at a total air void content of approximately 4 percent. The mixture should have a minimum VMA of 14 percent and between 65 percent and 80 percent of voids filled. 5. Asphalt cement should meet the requirements of the Superpave Performance Graded (PG) Binders. The minimum performing asphalt cement should conform to the requirements of the governing agency. 6. Hydrated lime should be added at the rate of 1 percent by dry weight of the aggregate and should be included in the amount passing the No. 200 sieve. Hydrated lime for aggregate pretreatment should conform to the requirements of ASTM C 207, Type N. 7. Paving should be performed on properly prepared, unfrozen surfaces that are free of water, snow and ice. Paving should only be performed when both air and surface temperatures equal, or exceed, the temperatures specified in Table 401-3 of the 2006 Colorado Department of Transportation Standard Specifications for Road and Bridge Construction. 8. HMA should not be placed at a temperature lower than 245o F for mixes containing PG 64-22 asphalt, and 290o F for mixes containing polymer-modified asphalt. The breakdown compaction should be completed before the HMA temperature drops 20o F. 9. Wearing surface course shall be Grading S or SX for residential roadway classifications and Grading S for collector, arterial, industrial, and commercial roadway classifications. 10. The minimum/maximum lift thicknesses for Grade SX shall be 1½ inches/2½ inches. The minimum/maximum lift thicknesses for Grade S shall be 2 inches/3½ inches. The minimum/maximum lift thicknesses for Grade SG shall be 3 inches/5 inches. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 D-4 11. Joints should be staggered. No joints should be placed within wheel paths. 12. HMA should be compacted to between 92 and 96 percent of Maximum Theoretical Density. The surface shall be sealed with a finish roller prior to the mix cooling to 185o F. 13. Placement and compaction of HMA should be observed and tested by a representative of our firm. Placement should not commence until approval of the proof rolling as discussed in the Subgrade Preparation section of this report. Subbase, base course or initial pavement course shall be placed within 48 hours of approval of the proof rolling. If the Contractor fails to place the subbase, base course or initial pavement course within 48 hours or the condition of the subgrade changes due to weather or other conditions, proof rolling and correction shall be performed again. Portland Cement Concrete (PCC) 1. Portland cement concrete should consist of Class P of the 2017 CDOT - Standard Specifications for Road and Bridge Construction specifications for normal placement or Class E for fast-track projects. PCC should have a minimum compressive strength of 4,200 psi at 28 days and a minimum modulus of rupture (flexural strength) of 600 psi. Job mix designs are recommended and periodic checks on the job site should be made to verify compliance with specifications. 2. Portland cement should be Type II “low alkali” and should conform to ASTM C 150. 3. Portland cement concrete should not be placed when the subgrade or air temperature is below 40°F. 4. Concrete should not be placed during warm weather if the mixed concrete has a temperature of 90°F, or higher. 5. Mixed concrete temperature placed during cold weather should have a temperature between 50°F and 90°F. 6. Free water should not be finished into the concrete surface. Atomizing nozzle pressure sprayers for applying finishing compounds are recommended whenever the concrete surface becomes difficult to finish. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 D-5 7. Curing of the Portland cement concrete should be accomplished by the use of a curing compound. The curing compound should be applied in accordance with manufacturer recommendations. 8. Curing procedures should be implemented, as necessary, to protect the pavement against moisture loss, rapid temperature change, freezing, and mechanical injury. 9. Construction joints, including longitudinal joints and transverse joints, should be formed during construction or sawed after the concrete has begun to set, but prior to uncontrolled cracking. 10. All joints should be properly sealed using a rod back-up and approved epoxy sealant. 11. Traffic should not be allowed on the pavement until it has properly cured and achieved at least 80 percent of the design strength, with saw joints already cut. 12. Placement of Portland cement concrete should be observed and tested by a representative of our firm. Placement should not commence until the subgrade is properly prepared and tested. APPENDIX E MAINTENANCE PROGRAM ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 E-1 MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS A primary cause for deterioration of pavements is oxidative aging resulting in brittle pavements. Tire loads from traffic are necessary to "work" or knead the asphalt concrete to keep it flexible and rejuvenated. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal or rejuvenating the asphalt binder to extend pavement life. 1. Annual Preventive Maintenance a. Visual pavement evaluations should be performed each spring or fall. b. Reports documenting the progress of distress should be kept current to provide information on effective times to apply preventive maintenance treatments. c. Crack sealing should be performed annually as new cracks appear. 2. 3 to 5 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 3 to 5 years to reduce oxidative embrittlement problems. b. Typical preventive maintenance treatments include chip seals, fog seals, slurry seals and crack sealing. 3. 5 to 10 Year Corrective Maintenance a. Corrective maintenance may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. b. Corrective maintenance may include full depth patching, milling and overlays. c. In order for the pavement to provide a 20-year service life, at least one major corrective overlay should be expected. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL  T PROJECT NO. FC08517-135 E-2 MAINTENANCE RECOMMENDATIONS FOR RIGID PAVEMENTS High traffic volumes create pavement rutting and smooth, polished surfaces. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal and improving skid resistance through a new wearing course. 1. Annual Preventive Maintenance a. Visual pavement evaluations should be performed each spring or fall. b. Reports documenting the progress of distress should be kept current to provide information of effective times to apply preventive maintenance. c. Crack sealing should be performed annually as new cracks appear. 2. 4 to 8 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 4 to 8 years to reduce joint deterioration. b. Typical preventive maintenance for rigid pavements includes patching, crack sealing and joint cleaning and sealing. c. Where joint sealants are missing or distressed, resealing is mandatory. 3. 15 to 20 Year Corrective Maintenance a. Corrective maintenance for rigid pavements includes patching and slab replacement to correct subgrade failures, edge damage and material failure. b. Asphalt concrete overlays may be required at 15 to 20 year intervals to improve the structural capacity of the pavement. 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING 0 10 20 30 50 60 70 80 90 100 PERCENT RETAINED 40 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING PERCENT RETAINED 0 10 20 30 40 50 60 70 80 90 100 FIGURE A-3 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING 0 10 20 30 50 60 70 80 90 100 PERCENT RETAINED 40 0.002 15 MIN. .005 60 MIN. .009 19 MIN. .019 4 MIN. .037 1 MIN. .074 *200 .149 *100 .297 *50 0.42 *40 .590 *30 1.19 *16 2.0 *10 2.38 *8 4.76 *4 9.52 3/8" 19.1 3/4" 36.1 1½" 76.2 3" 127 5" 152 6" 200 8" .001 45 MIN. 0 10 20 30 40 50 60 70 80 90 100 CLAY (PLASTIC) TO SILT (NON-PLASTIC) SANDS FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS PERCENT PASSING PERCENT RETAINED 0 10 20 30 40 50 60 70 80 90 100 FIGURE A-2 LL PI UC SS DEPTH - FEET THE BORINGS WERE DRILLED ON SEPTEMBER 9, 2019 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. NOTES: 1. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. DEPTH - FEET Summary Logs of Exploratory Borings - - - - - - - - INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%). INDICATES PASSING NO. 200 SIEVE (%). INDICATES LIQUID LIMIT. INDICATES PLACTICITY INDEX. INDICATES UNCONFINED COMPRESSIVE STRENGTH (psf). INDICATES SOLUBLE SULFATE CONTENT (%). 4. ARCHITECTURE WEST, LLC LOT 1, INDUSTRIAL BUSINESS PARK CTL | T PROJECT NO. FC08517-135 2. NO GROUNDWATER WAS ENCOUNTERED DURING THIS INVESTIGATION.