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HomeMy WebLinkAboutB12-0382 GEOTECHNICAL REPORTKOECHLEIN CONSULTING ENGINEERS, INC. GEOTECHNICAL AND MATERIALS ENGINEERS GEOTECHNICAL REPORT PROPOSED FORD PARK COMPLEX REDEVELOPMENT 580 SOUTH FRONTAGE ROAD EAST VAIL, COLORADO Job No. 09 -034 Prepared for: Todd Oppenheimer _ Town of Vail Department of Public Works D 1309 Elkhorn Drive Vail, CO 81657 "I 2 1 2012 TOWN OF VAIL September 10, 2009 DENVER: 12364 West Alameda Prkwy., Suite 115, Lakewood, CO 80228 (303) 989 -1223 GRAND JUNCTION. 52925 112 Rd* Suite 201 . Grand Junction, C081505(970)241-7700 AVON /SILVERTHORNE. (970) 949 -6009 31a -o38a September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers TABLE OF CONTENTS SCOPE I EXECUTIVE SUMMARY 2 SITE CONDITIONS 5 PROPOSED CONSTRUCTION 6 SUBSURFACE EXPLORATION 7 SUBSURFACE CONDITIONS 8 RADON 10 MOLD 10 EXISTING FILL 11 GROUND WATER 12 EXCAVATIONS 13 SHORING 14 SEISMICITY 15 DEWATERING 15 CORROSION 17 FOUNDATIONS 18 SLABS -ON -GRADE 20 FOUNDATION DRAINAGE 22 LATERAL WALL LOADS 23 RETAINING WALL 24 SURFACE DRAINAGE 25 COMPACTED FILL 26 PAVEMENT DESIGN 27 Flexible Pavement Design 28 Rigid Pavement Design 29 Pavement Materials 30 Subgrade Stabilization 31 Construction Considerations 32 Drainaee 33 LIMITATIONS 33 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers LIST OF FIGURES VICINITY MAP LOCATION OF EXPLORATORY BORING IN SOUTH AREA LOCATIONS OF EXPLORATORY BORINGS IN NORTH AREA LOGS OF EXPLORATORY BORINGS LEGEND OF EXPLORATORY BORINGS GRADATION TEST RESULTS FOUNDATION EXCAVATION RECOMMENDATIONS TYPICAL WALL DRAIN DETAIL TRAPEZOIDAL LATERAL EARTH PRESSURE TYPICAL RETAINING WALL DRAIN DETAIL SUMMARY OF LABORATORY TEST RESULTS PAVEMENT DESIGN CALCULATIONS PAVEMENT CONSTRUCTION RECOMMENDATIONS Fig. 1 Fig. 2 Fig.3 Figs. 4 and 5 Fig. 6 Figs. 7 thru 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Table I Appendix A Appendix B September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers SCOPE This report presents the results of a subsurface exploration performed for the proposed Ford Park Complex redevelopment project to be constructed at 580 South Frontage Road East in Vail, Colorado. The approximate site location is shown on the Vicinity Map, Fig. 1. The purpose of this report is to present the results of the subsurface exploration at the subject site and to provide geotechnical recommendations for the proposed construction. This report includes descriptions of subsurface soil and ground water conditions encountered in the exploratory borings, recommended foundation systems, allowable soil bearing pressure, engineering soil properties, and recommended foundation design and construction criteria. This report was prepared from data developed during our subsurface exploration, laboratory testing, and our experience with similar projects and subsurface conditions in the area. At the time of our subsurface exploration, the locations of the proposed structures within the site had not been fmalized. The recommendations presented in this report are based on the construction of a multi -level parking structure and recreation center building within the south and north site boundaries as indicated in the Location of Exploratory Boring in South Area, Fig. 2 and Locations of Exploratory Borings in North Area, Fig. 3. We should be contacted to review our recommendations when the final locations and plans for the proposed parking garage and recreation center building have been September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers completed. A summary of our findings and conclusions is presented in the following paragraphs. EXECUTIVE SUMMARY 1. Subsurface conditions encountered in the exploratory borings TH -1 thru TH -5 varied. The subsurface conditions encountered in exploratory boring TH -1 consisted of 3 inches of asphalt underlain by a medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 20.0 feet. The subsurface conditions encountered in exploratory borings TH -2 and TH -4 consisted of 2.5 to 6 inches of either asphalt or topsoil underlain by existing fill to varying depths of 6.0 to 12.0 feet. The existing fill is characterized by a medium dense to dense, gravelly sand with scattered cobbles and lenses of silty clay. Below the existing fill the subsurface conditions consisted of natural, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depths explored of 40.0 feet. The subsurface conditions encountered in boring TH -3 consisted of 6 inches of topsoil underlain by existing fill. The existing fill is characterized by a medium stiff, sandy clay to a depth of 4.0 feet. Below the existing fill the subsurface conditions consisted of natural, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 20.0 feet. The subsurface conditions encountered in boring TH -5 consisted of 2 inches of topsoil underlain by medium dense to dense, sandy silt to a depth of 4.0 feet. Below the silt, the subsurface conditions consisted of a medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 40.0 feet. Refer to the SUBSURFACE CONDITIONS section of this report for additional information. 2. At the time of drilling, ground water was encountered in boring TH -3 at a depth of 9.0 feet. Ground water was not encountered during drilling in borings TH -1, TH -2, TH -4, and TH -5 to the maximum depth explored of 20.0 feet in TH -1 and 40.0 feet in borings TH -2, TH -4, and TH -5. Refer to the GROUND WATER section of this report for additional details. 2 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers 3. Topsoil was encountered in borings TH -3 thru TH -5 to varying depths of 2 to 6 inches. Greater depths of topsoil could be encountered across the site. All topsoil below areas of proposed construction should be removed. Topsoil may be used in landscaped areas. 4. Asphalt was encountered in borings TH -1 and TH -2 to varying depths of 2.5 to 3 inches. Greater depths of asphalt could be encountered in paved areas across the site. All asphalt in the area of the proposed construction should be removed prior to the start of construction. 5. Existing fill was encountered in exploratory borings TH -2 thru TH -4 to varying depths of 4.0 to 12.0 feet. However, greater depths of existing fill could be encountered across the site. The existing fill encountered in borings TH -2 and TH -4 is characterized by tan, brown, slightly moist to moist, medium dense to dense, silty, gravelly sand with organics, scattered cobbles, and lenses of silty clay. The existing fill encountered in boring TH -3 is characterized by a dark brown, slightly moist, medium stiff, sandy clay, with some gravel. Refer to the EXISTING FILL section of this report for additional recommendations. 6. We anticipate that the subsurface conditions at the foundation elevation for the proposed parking garage will consist of the natural sand and gravel. It is our opinion that a spread footing foundation system constructed on the sand and gravel will have a low risk of movement. We anticipate that the subsurface conditions at the foundation elevation for the proposed recreation center building could consist either of existing fill or the natural sand and gravel. Due to the presence of existing fill at the foundation elevation, special consideration should be taken into account when selecting a foundation system for the proposed recreation center building. Refer to the FOUNDATIONS section of this report for complete recommendations. 7. We anticipate that the subsurface conditions at the proposed slabs -on- grade elevation for the proposed parking garage will consist of the natural sand and gravel. Slabs -on -grade constructed on the natural, sand and gravel will have a very low risk of movement. We anticipate that the subsurface conditions at the slab -on -grade elevation for the proposed recreation center building could consist of either existing fill or the natural sand and gravel. Due to the presence of existing fill at the slab -on -grade elevation, special considerations will need to be taken into account. Refer 3 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers to the SLABS -ON -GRADE section of this report for complete recommendations. 8. We anticipate excavation depths of up to 40 feet may be required for construction of the proposed parking garage and 4 feet for the proposed recreation center building. All cuts should be constructed as recommended in this report in order to maintain the stability of the slopes and sides of excavations. Refer to the EXCAVATIONS section of the report for additional details. 9. Based on the subsurface conditions encountered in the exploratory borings and depth of the anticipated excavations, we believe that heavy -duty construction equipment may be necessary to complete the required excavations. 10. Due to the anticipated depth of excavation for the proposed parking garage, we anticipate that a temporary shoring system may be necessary for the proposed construction. Refer to the SHORING section of this report for additional details 11. Laboratory tests were conducted on soil samples to determine their corrosive potential in order to evaluate any potential impact on construction activities. Refer to the CORROSION section of this report for additional information. 12. Drainage around the proposed parking garage and recreation center building should be designed and constructed to provide for rapid removal of surface runoff and avoid concentration of water adjacent to foundation walls. Refer to the SURFACE DRAINAGE section of this report for additional recommendations. 13. The potential for radon gas is a concern in the area. Refer to the RADON section of this report for additional recommendations. 14. The potential for mold is a concern in new construction. Refer to the MOLD section of this report for additional recommendations. 15. Based on the subsurface soil profile, this site has a seismic site classification of Site Class C. Refer to the SEISMICITY section of this report for additional details. September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers 16. Laboratory testing on the subgrade samples in borings TH -1 and TH -2 to a depth of 5.0 feet indicate that the soils classify as A -1 -a and A -1 -b soils in accordance with the AASHTO classification system. The pavement designs presented in this report are based on the subgrade soils classifying as A -1 -b soils 17. Pavement thickness design recommendations for the proposed parking lots are presented in the PAVEMENT DESIGN section and in Appendix A of this report. 18. Pavement construction recommendations are presented in the CONSTRUCTION CONSIDERATIONS section of this report and in Appendix B. SITE CONDITIONS The subject site is located at 580 South Frontage Road East in Vail, Colorado which is currently occupied by the existing Ford Park Complex. The existing Ford Park Complex consists of asphalt parking lots, concrete pathways, athletic fields, a concession stand, tennis courts, playgrounds, gardens, and an amphitheater. The existing structures are single -story in height with no below grade levels. Buildings are of wood frame and cast -in -place construction with slab -on -grade floors. The northern portion of the park is bordered to the north by South Frontage Road East, to the east and south by Gore Creek, and to the west by residential structures. The southern portion of the park is bordered to the north by Vail Valley Drive, to the east and south by the Vail Golf Club golf course, and to the west by Pinos Del Norte. At the time of our subsurface exploration the specific locations for the proposed parking garage and recreation center building had not been 5 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers determined. Overall site topography is gently rolling with a slope down towards the south at an approximate grade of 5 percent. However, the topography changes along the southern side of the north improvement area to a steep slope down towards Gore Creek at an approximate grade of 10 to 25 percent. The existing parking lots are constructed of asphalt pavement. Vegetation on -site consists of cut grasses within the athletic fields with tall pine and aspen trees in the adjacent landscaped areas. PROPOSED CONSTRUCTION We understand that the proposed project consists of the construction of a parking garage and recreation center building as well as the pavement of parking lots within the existing Ford Park Complex in Vail, Colorado. Prior to the start of our subsurface exploration a site plan showing the location of the requested exploratory borings was provided by the Town of Vail. At the time of our subsurface exploration, locations for the proposed structures had not been determined. We anticipate that the proposed parking garage will consist of a multi -level structure with up to three levels of above grade and three levels of below grade parking. The proposed parking garage will most likely consist of cast -in -place and pre -cast concrete construction with slab -on -grade floors at the lowest level. We anticipate that excavations up to 40 feet in depth may be necessary for construction of the proposed Ce September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers parking garage. Due to the potential for deep excavation cuts both temporary and /or permanent shoring systems may be necessary. We anticipate that the proposed recreation center building will consist of a structure with up to two- stories above grade and no below grade levels. The proposed recreation center building will be of cast -in -place concrete and wood frame construction with slab -on -grade floors. Excavations up to 4 feet in depth will likely be necessary for the construction of the proposed recreation center building. However, if the proposed recreation center building is constructed in the area of existing fill, excavation depths may be as deep as 12 feet. SUBSURFACE EXPLORATION Subsurface conditions were explored at this site on August 18, 19, and 20, 2009 by drilling a total of five exploratory borings (TH -1 thru TH -5). Exploratory borings TH- 1, TH -2, TH -4, and TH -5 were drilled using an air rotary percussion down -hole hammer mounted on a tracked drill rig at the approximate locations shown on the Location of Exploratory Boring in South Area, Fig. 2 and on the Locations of Exploratory Borings in North Area, Fig. 3. Boring TH -3 was drilled with a 4 -inch diameter continuous flight power auger mounted on a tracked drill rig at the approximate location shown on the Locations of Exploratory Borings in North Area, Fig. 3. 7 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers An engineer from our office was on site during the subsurface exploration to supervise the drilling of the exploratory borings and to visually classify and document the subsurface soils and ground water conditions. Graphical logs of the subsurface conditions encountered within the exploratory borings are presented on the Logs of Exploratory Borings, Figs. 4 and 5; and on the Legend of Exploratory Borings, Fig. 6. Soil samples obtained from the exploratory borings were visually classified and select samples were tested in our laboratory to determine their natural moisture content, natural dry density, gradation properties, Atterberg limits, and corrosive potential. Results of the laboratory testing are presented on the Logs of Exploratory Borings, Figs. 4 and 5; on the Gradation Test Results, Figs. 7 thru 10; and on the Summary of Laboratory Test Results, Table I. SUBSURFACE CONDITIONS Subsurface conditions encountered in exploratory borings TH -1 thru TH -5 varied. The subsurface conditions encountered in exploratory boring TH -1 consisted of 3 inches of asphalt underlain by a brown, slightly moist to wet, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 20.0 feet. The subsurface conditions encountered in exploratory borings TH -2 and TH -4 consisted of 2.5 to 6 inches of either asphalt or topsoil underlain by existing fill to varying depths of 6.0 to 12.0 feet. The existing fill is characterized by a tan, brown, slightly moist E September 10, 2009 KOECALEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers to moist, medium dense to dense, silty, gravelly sand with organics, scattered cobbles, and lenses of silty clay. Below the existing fill the subsurface conditions consisted of a natural, brown, slightly moist to wet, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depths explored of 40.0 feet. The subsurface conditions encountered in boring TH -3 consisted of 6 inches of topsoil underlain by existing fill. The existing fill is characterized by a dark brown, slightly moist, medium stiff, sandy clay, with some gravel to a depth of 4.0 feet. Below the existing fill the subsurface conditions consisted of a natural, brown, slightly moist to wet, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 20.0 feet. The subsurface conditions encountered in TH- 5 consisted of 2 inches of topsoil underlain by a brown, dry to slightly moist, medium dense to dense, sandy silt with scattered gravels and cobbles to a depth of 4.0 feet. Below the silt, the subsurface conditions consisted of a brown, slightly moist to wet, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to the maximum depth explored of 40.0 feet. At the time of drilling, ground water was encountered in boring TH -3 at a depth of 9.0 feet. Ground water was not encountered during drilling in borings TH -1, TH -2, TH -4, and TH -5 to the maximum depth explored of 20.0 feet in TH -1 and 40.0 feet in borings TH -2, TH -4, and TH -5. 0j September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers RADON In recent years, radon gas has become a concern. Radon gas is a colorless, odorless gas that is produced by the decay of minerals in soil and rock. The potential for radon gas in the subsurface strata is likely. Since the proposed parking garage could be constructed with up to three levels of below grade parking, the risk of radon gas for this structure is high. We suggest that all below grade levels be designed with ventilation for these areas. Because the proposed recreation center will likely be constructed with no below grade levels, the risk for radon gas for this structure is low. However, if plans change and below grade levels are added, we recommend all below grade levels be designed with ventilation for these areas. MOLD Mold has become a concern with new construction. Mold tends to develop in dark or damp areas such as below grade levels, under floor spaces, or bathrooms. Recommendations for the prevention, remediation, and /or mitigation of mold is outside the scope of this report. We recommend that the owner contact a Professional Industrial Hygienist for recommendations for the prevention, remediation, and /or mitigation of mold. 10 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers EXISTING FILL Existing fill was encountered in exploratory borings TH -2 thru TH -4 to varying depths of 4.0 to 12.0 feet. However, greater depths of existing fill could be encountered across the site. The existing fill encountered in borings TH -2 and TH -4 is characterized by tan, brown, slightly moist to moist, medium dense to dense, silty, gravelly sand with scattered cobbles and lenses of silty clay. The existing fill encountered in boring TH -3 is characterized by a dark brown, slightly moist, medium stiff, sandy clay, with scattered gravels and cobbles. All existing fill should be removed and replaced with properly moisture conditioned and compacted new structural fill where new structures will be constructed. Due to the necessary depth of the excavation for the proposed parking garage, we anticipate that all existing fill will be removed in the initial excavation and will not likely influence the construction of the proposed parking garage. However, the presence of existing fill could influence the construction of the proposed recreation center building. The final location of the proposed recreation building should be carefully selected to an area with the least amount of existing fill. When the final location the proposed recreation center building is determined, an additional site specific subsurface exploration could be performed in order to better define the limits of the existing fill within the final location. 11 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers We anticipate that the existing, gravelly sand fill may be used as structural fill for this project. However, we do not recommend that that the existing, silty clay fill be used as structural fill for this area. The existing, silty clay fill may be placed in landscaped areas. Existing fill should be evaluated by a representative of our office prior to its use to determine placement criteria as structural fill. Refer to the COMPACTED FILL section of this report for additional recommendations. GROUND WATER At the time of drilling, ground water was encountered in boring TH -3 at a depth of 9.0 feet. Ground water was not encountered during drilling in borings TH -1, TH -2, TH -4, and TH -5 to the maximum depth explored of 20.0 feet in TH -1 and 40.0 feet in borings TH -2, TH -4, and TH -5. Based on the encountered ground water conditions, the anticipated excavation depths, and depending upon where the proposed structures are constructed across the site, it is possible that ground water could adversely affect the construction of the proposed parking garage. However, we do not anticipate that ground water will adversely affect the construction of the proposed recreation center building. If ground water is encountered during construction, both temporary and permanent dewatering may be necessary. Refer to the DEWATERING section of this report for additional information. 12 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers EXCAVATIONS We anticipate that excavation depths of up to 40 feet could be necessary for construction of the proposed parking garage, while excavations of up to 4 feet will be necessary for construction of the proposed recreation center building. However, if the proposed recreation center building is constructed in the area of existing fill, excavation depths may be as deep as 12 feet. Based on the subsurface conditions encountered in the exploratory borings, it is our opinion that heavy -duty excavation equipment will be necessary to complete the required excavations. Care needs to be exercised during construction so that the excavation slopes remain stable. In our opinion, the existing fill, natural silt, and natural sand and gravel above the water table classify as Type B soils in accordance with OSHA classifications. The existing fill, natural silt, and natural sand and gravel below the water table classify as Type C soils in accordance with OSHA regulations. OSHA regulations should be followed in any excavations or cuts. Existing fill was encountered at this site to varying depths of 4.0 to 12.0 feet. Greater depths of existing fill could be encountered across the site. All existing fill located below areas of construction should be removed. If necessary these areas may be brought back to finished grade with properly moisture conditioned and compacted new structural fill as outlined in the COMPACTED FILL section of this report. Asphalt and topsoil was encountered to varying depths of 2 to 6 inches. Greater 13 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers amounts of asphalt and topsoil could be encountered across the site. All asphalt and topsoil located below areas of construction should be removed prior to the start of construction. Topsoil may be used in landscaped areas. SHORING Based on the proposed construction, we anticipate that the parking garage will require excavations of up to 40 feet in depth. While the location of the proposed parking garage had not been finalized at the time of the issue of this report, we anticipate that the construction of the garage could be influenced by existing structures and athletic fields across the Ford Park Complex. Due to the depth of excavation and close proximity of utilities, roadways, and existing structures, it may not be possible to slope all of the excavation sides as required by OSHA regulations. Therefore, a temporary shoring system may be necessary. The ability to complete the excavation within the site constraints and the need for a shoring system including the type of system should be evaluated during the design phase of the project. Due to the constant evolution of shoring systems, we recommend a contractor specializing in shoring be contacted to provide applicable shoring system alternatives and associated design and construction criteria. If requested, we can assist the owner in selecting an appropriate shoring system after a shoring contractor has been contacted. 14 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSUL TING ENGINEERS, INC. Geotechnical and Materials Engineers The subsurface conditions encountered across the Ford Park Complex site consisted of existing sand fill, existing clay fill, natural silt, and natural sand and gravel. Engineering properties of the soils are based on visual observation and laboratory testing that was conducted. The following table outlines engineering properties of the soils that may be used in design of the proposed shoring system. Soil Type Y (c (degrees) C (psf) FILL, Sand 120 35 0 FILL, Clay 105 0 200 SILT 115 30 0 SAND and GRAVEL 135 35 0 SEISMICITY The subsurface soil and ground water conditions encountered within the exploratory borings indicate that the soil profile classifies as a very dense soil and soft rock profile. Based on this classification and the International Building Code (IBC), it is our opinion that the subject site has a seismic site classification of Site Class C. DEWATERING At the time of drilling ground water was encountered in boring TH -3 at a depth of 9.0 feet. Groundwater was not encountered during drilling in borings TH -1, TH -2, TH -4, and TH -5 to the maximum depth explored of 20.0 feet in TH -1 and 40.0 feet in borings TH -2, TH -4, and TH -5. Ground water in mountain terrain typically travels in more 15 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers permeable layers of soil. Therefore, ground water may be encountered at various elevations across the site. During wetter times of the year, ground water may be encountered at higher elevations. If construction begins after July 15'', it is our opinion, less ground water may be encountered. Based on the proposed construction, excavations for the proposed parking garage could be up to 40 feet below the current ground surface elevation, while excavations for the proposed recreation center building will be approximately 4 below the ground surface elevation. Because ground water was encountered in the exploratory borings above the proposed excavation depths for the proposed parking garage, we anticipate that both temporary and permanent dewatering systems will be necessary. Temporary dewatering methods that have worked in this area to control the ground water have consisted of either shallow trenches or interceptor trenches. Shallow trenches can be constructed in the footing excavations adjacent to the proposed footings and can be sloped to a sump pit where the water can be removed by pumping. Due to the potential for shallow ground water and the required depth of excavation for the proposed parking garage, permanent dewatering will be required for the construction of the proposed parking garage. The permanent dewatering system should consist of an underslab drain in conjunction with foundation wall drains. These two systems could be combined and sloped to a sump pit where the water can be removed by pumping. Because the water will require pumping, we recommend that the permanent 16 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers dewatering system be designed with redundant pumps and possibly with backup power. The underslab drain may consist of a series of lateral and collection pipes sloped to the sump pit, while the foundation wall drains may consist of a manufactured wall drain and collection pipes sloped to a sump pit. A professional Civil Engineer or Dewatering Consultant should be contacted to layout the underslab drains, foundation wall drains and sump pit locations. If requested, we can assist the dewatering system designer. CORROSION Laboratory tests were conducted on soil samples to determine the corrosive potential of the on -site soils and to evaluate any potential impact on construction activities. Conductivity, resistivity, pH, as well as soluble chloride and sulfate testing was conducted on the sand and gravel and the sandy silt. The sand and gravel at a depth of 14.0 feet had a resistivity of 4,300 Ohm- centimeters, a pH of 7.0, water soluble chloride concentration of 14.0 ppm, and soluble sulfate concentration of 0 ppm. The sandy silt at 0.2 - 4.0 feet had a resistivity of 5,800 Ohm- centimeters, a pH of 7.1, water soluble chloride concentration of 4.8 ppm, and soluble sulfate concentration of 0 ppm. The results of these tests are presented in the Results of the Summary of Laboratory Test Results, Table I. Chloride concentrations greater than or equal to 500 ppm, sulfate concentrations greater than or equal to 2000 ppm, a pH of less than 5.5, and a resistivity of 1,000 Ohm- 17 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers centimeter or less indicate a high corrosion potential. Based on the laboratory test results, the sand and gravel and sandy silt have a negligible corrosive potential. In our opinion, no special cement requirements will be required for concrete elements that come in contact with the on -site soils. FOUNDATIONS While the final locations of the proposed parking garage and recreation center building have not been determined, based on the subsurface exploration and the proposed construction, we anticipate that the material at the foundation elevation for the proposed parking garage will consist of the natural sand and gravel. The material at the foundation elevation for the proposed recreation center building will consist either of existing clay fill, sand fill, or natural sand and gravel. It is our opinion that spread footings constructed on the natural sand and gravel or properly moisture treated and compacted structural fill will have a low risk of movement. Spread footings constructed on the existing fill will have a high risk of movement. We do not recommend that spread footings be constructed on the existing fill. If the owner would like to construct the proposed structures in areas of existing fill, we recommend that all existing fill below the proposed construction be removed and, if necessary, replaced with properly moisture treated and compacted structural fill. We recommend that spread footings at these sites be designed and constructed to meet the following criteria: IN September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers Spread footings should be supported by either the natural sand and gravel or properly moisture conditioned and compacted non - expansive structural fill. 2. Footings at depths less than 20 feet from the current ground surface may be designed for a maximum allowable soil bearing pressure of 4,000 psf. Footings at depths greater than 20 feet from the current ground surface may be designed for a maximum allowable soil bearing pressure of 6,000 psf. Existing fill was encountered to varying depths of 4.0 to 12.0 feet in exploratory borings TH -2 thru TH -4. Greater depths of existing fill could be encountered across the site. Topsoil and asphalt was encountered to varying depths of 2 to 6 inches in the exploratory borings. Greater depths of topsoil and asphalt could be encountered across the site. Any topsoil, asphalt, and all existing fill must be removed in order to expose the natural soils. If necessary, properly moisture conditioned and compacted non- expansive structural fill may be placed beneath the proposed foundations. Refer to the COMPACTED FILL section of this report for structural fill requirements. 4. Spread footings constructed on the natural sand and gravel or properly moisture conditioned and compacted structural fill should experience less than 0.5 inch of differential movement between foundation elements. Because the soils are granular, we anticipate that the majority of the settlement will occur during construction. Continuous foundation systems should be designed to span a distance of at least 10 feet in order to account for anomalies in the soil or fill. 6. Compacted structural fill placed beneath spread footings should extend at a 1 to 1 (Horizontal to Vertical) slope from the outside edge of the footings. Excavation recommendations beneath spread footings are shown in the Foundation Excavation Recommendations, Fig. 11. 7. The base of the exterior footings should be established at a minimum depth below the exterior ground surface, as required by the local building code. We believe that the depth for frost protection in the local building code in this area is 40 inches. 19 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers 8. Column footings should have a minimum dimension of 24 inches square and continuous wall footings should have a minimum width of 16 inches. Footing widths may be greater to accommodate structural design loads. 9. Pockets or layers of soft soils or existing fill may be encountered in the bottom of the completed footing excavations. These materials should be removed to expose the undisturbed natural sand and gravel. The foundations should be constructed on the natural sand and gravel or new structural fill. Refer to the COMPACTED FILL section of this report for backfill requirements. 10. Structural fill should be placed and compacted as outlined in the COMPACTED FILL section of this report. We recommend that a representative of our office observe and test the compaction of structural fill used in foundation construction during the placement process. It has been our experience that without engineering quality control, inappropriate construction techniques can occur which result in unsatisfactory foundation performance. 11. A representative from our office must observe the completed foundation excavations. Variations from the conditions described in this report, which were not indicated by the borings, can occur. The representative can observe the excavations to evaluate the exposed subsurface conditions. SLABS -ON -GRADE While the final locations of the proposed parking garage and recreation center building have not been determined, based on the subsurface exploration and the proposed construction, we anticipate that the subsurface conditions at the approximate slab -on- grade elevation for the proposed parking garage should consist of the natural sand and gravel while the conditions at the approximate slab -on -grade elevation for the proposed recreation center building could consist of either topsoil, asphalt, existing fill, or natural sand and gravel. It is our opinion that slabs -on -grade could be constructed on the natural, 20 September 10, 2009 Job No. 09 -034 XOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers sand and gravel with a very low risk of movement. Slabs -on -grade constructed on the existing fill will have a high risk of movement. We do not recommend that slabs -on- grade be constructed on the existing fill. We recommend the following precautions for the construction of slabs -on -grade at these sites: 1. Slabs -on -grade may be constructed on the natural sand and gravel or properly moisture conditioned and compacted structural fill with a very low risk of movement. 2. Existing fill was encountered in exploratory borings TH -2 thru TH -4 to varying depths of 4.0 to 12.0 feet. Greater depths of existing fill could be encountered across the site. All existing fill should be removed and, if necessary, replaced with properly moisture treated and compacted structural fill. Refer to the COMPACTED FILL section of this report for structural fill requirements. 3. Topsoil and asphalt was encountered to varying depths of 2 to 6 inches in the exploratory borings. Greater depths of topsoil and asphalt could be encountered across the site. All topsoil and asphalt should be removed from below slabs -on -grade. 4. Slabs -on -grade may be designed using a modulus of subgrade reaction of 150 psi. 5. Slabs should be separated from exterior walls and interior bearing members. Vertical movement of the slab should not be restricted. 6. Exterior slabs should be separated from the parking garage and the recreation center building. These slabs should be reinforced to function as independent units. Movement of these slabs should not be transmitted directly to the foundations or walls of these structures. 7. Frequent control joints should be provided in all slabs to reduce problems associated with shrinkage of the concrete. 8. Structural fill beneath slabs -on -grade may consist of the existing sand fill, natural sand and gravel, or approved imported, non - expansive fill. 21 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers Structural fill should be placed and compacted as outlined in the COMPACTED FILL section of this report. We recommend that a representative of our office observe and test the placement and compaction of each lift of structural fill used in slab -on -grade construction. It has been our experience that without engineering quality control, inappropriate construction techniques can occur which results in unsatisfactory slab performance. FOUNDATION DRAINAGE Surface water tends to flow through relatively permeable backfill typically found adjacent to foundations. The water that flows through the fill collects on the surface of relatively impermeable soils occurring at the foundation elevation. Both this surface water and possible ground water can cause wet or moist below grade conditions after construction. It is our understanding that the proposed recreation center building will not be constructed with below grade levels. Provided no below grade levels or crawl spaces are constructed, it is our opinion that a foundation drain will not be necessary for the proposed recreation center building. However, due to the depth of the excavation for the proposed parking garage we anticipate that below grade walls will be constructed, therefore, we recommend the installation of an exterior drain along the below grade foundation walls of the proposed parking garage. The foundation drain for the below grade area of the proposed parking garage may consist of a manufactured wall drain and gravel. The gravel should have a maximum size of 1.5 inches and a maximum of 3 percent passing the No. 200 sieve. Screened aggregate 22 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers will be satisfactory for the drainage layer. The manufactured drain should extend from the bottom of the retaining wall to within 2 feet of subgrade elevation. The water can be drained by a perforated pipe with collection of water at the bottom of the wall leading to a sump pit where water can be pumped out. Recommended details for typical foundation wall drains are presented in the Typical Wall Drain Detail, Fig. 12. LATERAL WALL LOADS Based on the proposed construction we anticipate that the parking garage will be constructed with below grade walls that will require lateral earth pressures for design. Lateral earth pressures depend on the type of backfill and the height and type of wall. Walls, which are free to rotate sufficiently to mobilize the strength of the backfill, should be designed to resist the "active" earth pressure condition. Walls that are restrained should be designed to resist the "at rest" earth pressure condition. The following table presents the lateral wall pressures that may be assumed for design with on -site soils for walls less than 15 feet in height. 23 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers Earth Pressure Condition Equivalent Fluid Pressure ( cf) Active 40 At -rest 60 Passive 300 Notes: 1. Equivalent fluid pressures are for a horizontal backfill condition with no hydrostatic pressures or live loads. 2. A coefficient of friction of 0.5 may be used at the base of footings to resist lateral wall loads. Walls greater than 15 feet in height that are braced may be designed using the lateral earth pressure diagram presented in the Trapezoidal Lateral Earth Pressure (Braced Walls — Dewatered), Fig. 13 of this report. RETAINING WALL Based on the proposed depth of excavation for the proposed parking garage, we anticipate that retaining walls will be constructed as part of the development of the site. Foundations for retaining walls may be designed and constructed as outlined in the FOUNDATIONS section of this report. Lateral earth loads for retaining wall designs are presented in the LATERAL WALL LOADS section of this report. In order to reduce the possibility of developing hydrostatic pressures behind retaining walls, a drain should be constructed adjacent to the wall. The drain may consist of a manufactured drain system and gravel. The gravel should have a maximum size of 1.5 inches and have a maximum of 3 percent passing the No. 200 sieve. Screened aggregate will be satisfactory for the drainage layer. The manufactured drain should extend from the bottom of the retaining 24 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers wall to within 2 feet of subgrade elevation. The water can be drained by a perforated pipe with collection of the water at the bottom of the wall leading to a positive gravity outlet. A typical detail for a retaining wall drain is presented in the Typical Retaining Wall Drain Detail, Fig. 14. SURFACE DRAINAGE Reducing the wetting of structural soils and the potential of developing hydrostatic pressure behind below grade walls can be achieved by carefully planned and maintained surface drainage. We recommend the following precautions be observed during construction and maintained at all times after the proposed construction has been completed. 1. Wetting or drying of the open excavations should be minimized during construction. 2. All surface water should be directed away from the top and sides of the excavations during construction. 3. The ground surface surrounding the exterior of the proposed structures should be sloped to drain away from the structures in all directions. We recommend a slope of at least 12 inches in the first 10 feet in landscaped areas. 4. Hardscape (concrete and asphalt) should be sloped to drain away from the structures. We recommend a slope of at least 2 percent for all hardscape within 10 feet of the structures. 5. Backfill, especially around foundation walls, should be placed and compacted as recommended in the COMPACTED FILL section of this report. 25 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers 6. Roof drains should discharge at least 10 feet away from foundation walls with drainage directed away from the structures. 7. Surface drainage for this site should be designed by a Professional Civil Engineer. COMPACTED FILL Structural fill for this project may consist of the existing sand fill free of deleterious material, the natural sand and gravel, or approved imported, non - expansive structural fill. A representative of our office should evaluate the condition of the existing fill during to construction to verify its suitability as structural fill. Topsoil and the existing clay fill are not suitable for use as structural fill and should be removed prior to construction. The topsoil and existing clay fill may be used in landscape areas. Imported fill may consist of non - expansive silty or clayey sands or gravels with up to 30 percent passing the No. 200 sieve with a maximum plasticity index of 10. No cobbles larger than 10 inches should be placed in fill areas. Fill areas should be stripped of all vegetation, topsoil, and existing fill, and then scarified. Fill should be placed and compacted in thin loose lifts, moisture conditioned and compacted to the recommended compaction shown in the following table. The recommended compaction varies for the given use of the fill. 26 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers Use of Fill Recommended Compaction Percentage of the Standard Proctor Maximum Dry Density (ASTM D -698) Percentage of the Modified Proctor Maximum Dry Density (ASTM D -1557) Below Structure Foundations 98 95 Below Slabs -on -Grade 95 90 Utility Trench Backfill 95 90 Pavement Sub grade 95 (AASHTO T -99 90 (AASHTO T -180) Base Course 98 (AASHTO T -99) 95 (AASHTO T -180) Backfill (Non - Structural) 90 1 90 Note : 1. For granular soils, the moisture content should be —2 to +2 percent of the optimum moisture content. We recommend that a representative of our office observe and test the placement and compaction of each lift placed for structural fill. Fill placed below foundations, slabs -on- grade, retaining walls, and pavement sections is considered structural. It has been our experience that without engineering quality control, inappropriate construction techniques can occur which result in unsatisfactory foundation, slab -on- grade, retaining wall, and pavement performance. PAVEMENT DESIGN As part of the redevelopment of this site, we anticipate that parking lots will be constructed adjacent to the athletic fields in the general vicinity of the existing parking lots. We anticipate that both flexible pavement and rigid pavement may be used for the construction of the proposed parking lots. It is recommended that rigid pavement be used 27 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers in high traffic areas such as entrances or where heavy vehicles (fire trucks and trash trucks) turn or maneuver. The following sections present design assumptions, recommended flexible pavement sections, and recommended rigid pavement sections. Flexible Pavement Design The design of the flexible pavement sections was based upon an Equivalent Daily Load Application (EDLA), laboratory test results, and the Colorado Department of Transportation Pavement Design Manual. Design calculations for the parking lots were based on engineering soil characteristics from soil samples encountered in exploratory borings TH -1 and TH -2 to a depth of 5.0 feet. The subsurface conditions encountered in exploratory boring TH -1 consisted of 3 inches of asphalt underlain by brown, slightly moist to wet, medium dense to very dense, silty, sand and gravel with cobbles and scattered boulders to a depth of 5 feet. The subsurface conditions encountered in boring TH -2 consisted of 2.5 inches of asphalt underlain by a tan, brown, slightly moist to moist, medium dense to dense, silty, sand and gravel with organics, scattered cobbles, and lenses of silty clay to a depth of 5 feet. Laboratory test results indicated that the soils encountered within exploratory boring TH -1, to a depth of 5.0 feet, classify as A -1 -a soils, as defined by the AASHTO classification system. The soils encountered within exploratory 28 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers boring TH -2, to a depth of 5.0 feet, classify as A -1 -b soils. The pavement section designs presented in this report are based on the subgrade soils classifying as A -1- b soils. This soil type was assumed to have an Hveem Stabilometer R -value of 50. The R -value was estimated from the AASHTO classification of the soil. An EDLA was taken as 10 for traffic and parking areas. Flexible pavement sections for the subject side are shown in the following table. Full Depth Asphalt (inches) Asphalt + Base Course (inches) 5.0 4.0+6.0 Flexible pavement design values and calculations are presented in the Pavement Design Calculations, Appendix A. Rigid Pavement Design A rigid pavement section was designed using an EDLA value of 10 as used in the flexible pavement design. The subgrade soils were assumed to have a modulus of subgrade reaction of 150 psi /in. The rigid pavement design is based on the working stress of the concrete, which is assumed to be 650 psi. The Colorado Department of Transportation Pavement Design Manual, along with the above mentioned design values, was used to determine a rigid pavement section. The rigid pavement design resulted in a design section of 5.0 inches of concrete. 29 September 10, 2009 Job No. 09 -034 Pavement Materials KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers The design of a pavement system is as much a function of the paving materials as the support characteristics of the subgrade. The quality of the construction materials is reflected by the structural coefficients used in the design calculations. If the pavement system is constructed of inferior materials, the life and serviceability will be substantially reduced. The asphalt component of the pavement is designed assuming at least 1,800 pounds Marshall stability (strength coefficient of 0.44). Normally, an asphalt aggregate should be relatively impermeable to moisture and should be designed as a well - graded mix. The oil content and voids ratio also need to be determined to verify compliance with the mix design. We recommend a job mix design be performed and periodic checks be made to verify compliance with the specifications for this project. All asphalt should be compacted to between 92 and 96 percent of the maximum theoretical density. During asphalt placement, joints between asphalt rows should be feathered such that the surface water is shed from the asphalt surface. For a more thorough description of our pavement construction recommendations, please refer to Appendix B. 30 September 10, 2009 Job No. 09 -034 Subgrade Stabilization KOECHLEIN CONSUL TING ENGINEERS, INC. Geotechnical and Materials Engineers Based on our subsurface exploration, it is possible that existing fill could be encountered during the construction of the proposed parking lots. Pavements constructed on existing fill may experience a shortened life expectancy. Movement of the pavement may result in cracking, high and low spots, and other distress. Repair of high and low spots and cracking in the pavements should be expected if pavements are constructed on the existing fill. If the owner is willing to accept the risk of premature deterioration of the pavements, then the flexible pavements may be constructed on the existing fill. If the owner would like to reduce the risk of early pavement deterioration due to the existing fill, we recommend that 3.0 feet of the existing fill be removed and replaced with a non - expansive structural fill. Construction of pavements on properly moisture conditioned and compacted non - expansive fill should experience a typical life expectancy, provided proper maintenance is provided. If fill is required to obtain the final pavement subgrade elevation, the fill should consist of non - expansive material and be moisture treated and compacted as recommended in the COMPACTED FILL section of this report. 31 September 10, 2009 Job No. 09 -034 Construction Considerations KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers Major utilities, such as water and sewer, are usually placed beneath pavements during construction. If utilities are installed, the trench backfill should be observed, tested, and approved prior to paving. Careful attention should be paid to compaction of curb lines and around manholes. Excavation of completed pavements for utility construction and repair can destroy the integrity of the pavement and result in a severe decrease in serviceability. To restore the pavement to its original serviceability, careful control of backfill compaction and repaving is necessary. If utilities are to be installed beneath the proposed access drive or parking lot, the utilities should be installed, tested, and approved prior to paving. We do not anticipate that construction of the proposed parking lots will take place during cold weather. However, if plans change, caution should be employed when constructing during freezing times of the year. Construction on frozen subgrade soils may result in damage to the pavement. When the subgrade thaws, premature pavement failure may occur. Pavement or fill should be placed on unfrozen or frost -free subgrade soils. Frozen subgrade soils should be allowed to thaw or be removed and replaced to prevent future problems caused by the frozen subgrade. For a more thorough description of our pavement construction recommendations, please refer to Appendix B. 32 September 10, 2009 KOECHLEIN CONSULTING ENGINEERS, INC. Job No. 09 -034 Geotechnical and Materials Engineers Drainage The primary cause of saturated subgrade soils and early pavement deterioration is water infiltration into the pavement system. The addition of moisture usually results in softening of the subgrade, potential frost heave, and the eventual failure of the pavement section. In order to reduce the risk of water infiltration below the pavement section and potential frost heave, we recommend that a surface drainage system be designed, constructed, and maintained in order to provide rapid removal of surface runoff. The design cross -slope should be maintained. If curb and gutter is installed, seals should be provided between curb and pavement and all joints to reduce moisture infiltration. LIMITATIONS Although the exploratory borings were located to obtain a reasonably accurate determination of foundation and subgrade conditions, variations in the subsurface conditions are always possible. Any variations that exist beneath the site generally become evident during excavations for the proposed structures. Therefore, we should be contacted by the contractor and/or owner so that a representative of our office can observe the completed excavation to confirm that the soils are as indicated by the exploratory 33 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers borings and to verify our foundation and slab -on -grade design and construction recommendations. The placement and compaction of fill, as well as installation of foundations, should also be observed and tested. The design criteria and subsurface data presented in this report are valid for 3 years provided that a representative from our office observes the site at that time and confirms that the site conditions are similar to the conditions presented in the SITE CONDTIONS section of this report and that the recommendations presented in this report are still applicable. We recommend that fmal plans and specifications for proposed construction be submitted to our office for study, prior to beginning construction, to determine compliance with the recommendations presented Routine maintenance, such as sealing and repair of cracks annually and overlays at 5 to 10 year intervals, is generally necessary to achieve long -term life of a pavement system. In addition, positive drainage must be maintained at all times in order to reduce the risk of pavement failure. 34 September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers We appreciate the opportunity to provide this service. If we can be of further service in discussing the contents of this report or in the analyses of the proposed structures from a geotechnical viewpoint, please contact our office. KOECHLEIN CONSULTING ENGINEERS, INC. Jessica E. Street, E.I. Staff Engineer Reviewed by: Scott B. Myers, P.E. Senior Engineer (4 copies sent) 35 �i L r (Generated by MapQuest on 8/26/09) NOT TO SCALE R;vt__ NORTH AREA VICINITY MAP KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers al SOUTH AREA JOB NO. 09 -034 FIG. 1 t in= 100ft JOB NO. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers v L / \ ATHLETIC FIELD Q) EXISTING RESTROOM BUILDING LOCATION OF EXPLORATORY BORING IN SOUTH AREA FIG. 2 = m •c K, W W W Z=u U2 Z m W p 02 Z y f C J N 7 H q Z C OL U V = O W m 2U U W O Y Q w Q O z z V z EE Q m } O Q O J CL x w U- 0 cn z O a U O J 25 30 35 W1 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers TH -3 APP.EL. 8235 0 9/12 WC =28 D D =92 o LL =46 Q :- �. P1 =17 5 23/12 d: R� �: ti 50/6 bQ•: -200=14 10 50/5 LOGS OF EXPLORATORY BORINGS 15 v m T 20 m m 25 30 35 Ell JOB NO. 09-034 FIG. 4 TH -1 N Q- TH -2 APP. EL. 8229 APP. EL. 8246 0 CL =14.0 �' SS =O Q WC =4 PH =7.0 w a - 200 =12 RES =4300 W C3: OD'd LL =NL O . LX P1 =NP 20 d 50/9 2�' o: 50/7 o: WC =3 o o� 50/11 DD =118 44/18 5 y �3 bra - 200 =22 2019 LL =NL a P1 =NP � c3: b 50/11 17/18 10 ! Q�: 25 30 35 W1 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers TH -3 APP.EL. 8235 0 9/12 WC =28 D D =92 o LL =46 Q :- �. P1 =17 5 23/12 d: R� �: ti 50/6 bQ•: -200=14 10 50/5 LOGS OF EXPLORATORY BORINGS 15 v m T 20 m m 25 30 35 Ell JOB NO. 09-034 FIG. 4 N Q- 34/12 15 rd o WC =5 �p CL =14.0 �' SS =O PH =7.0 w a o RES =4300 W C3: OD'd O . 20 d 50/9 (L o: WC =3 o DD =118 - 200 =22 25 30 35 W1 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers TH -3 APP.EL. 8235 0 9/12 WC =28 D D =92 o LL =46 Q :- �. P1 =17 5 23/12 d: R� �: ti 50/6 bQ•: -200=14 10 50/5 LOGS OF EXPLORATORY BORINGS 15 v m T 20 m m 25 30 35 Ell JOB NO. 09-034 FIG. 4 TH -4 APP.EL. 8216 0 15 w w u_ = 20 a w 0 25 30 KOECHLEIN CONSULTING ENGINEERS, INC. 20/12 5 Qd s WC =7 APP. EL. 8218 DD =104 ►_' o, : - 200 =21 A �3: q �}. 50/9 9da 0o r io Q� SS =O ►0 18/12 10 15 w w u_ = 20 a w 0 25 30 KOECHLEIN CONSULTING ENGINEERS, INC. 50/7 Geotechnical and Materials Engineers Qd s WC =5 APP. EL. 8218 DD =103 ►_' o, : - 200 =11 35 40 50/3 10 15 v m 20 = m m 50/6 WC =6 25 DD =103 - 200 =13 30 35 40 LOGS OF EXPLORATORY BORINGS JOB NO. 09-034 FIG. 5 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers TH -5 APP. EL. 8218 0 WC =4 q �}. 50/9 0o CL =4.8 5 Q� SS =O e PH =7.1 �3 RES =5800 50/3 10 15 v m 20 = m m 50/6 WC =6 25 DD =103 - 200 =13 30 35 40 LOGS OF EXPLORATORY BORINGS JOB NO. 09-034 FIG. 5 LEGEND: ■ ASPHALT SAND and GRAVEL, Silty, Cobbles, Scattered boulders, Slightly moist to wet, Medium dense to very dense, Brown. FILL, Sand, Gravelly, Silty, Scattered cobbles, Lenses of silty clay, Organics, Slightly moist to moist, Medium dense to dense, Tan, Brown. ® TOPSOIL FILL, Clay, Sandy, Some gravel, Slightly moist, Medium stiff, Dark brown. FMSILT, Sandy, Scattered gravels and cobbles, Dry to slightly moist, Medium dense to dense, Brown. WATER. Indicates depth of water encountered while drilling. BULK SAMPLE. Obtained from percussion down - hole hammer cuttings. a CALIFORNIA DRIVE SAMPLE. The symbol 50/7 indicates that 50 blows of a 140 pound hammer falling 30 inches were required to drive a 2.5 inch O.D. sampler 7 inches. Notes: KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers ' SPLIT SPOON DRIVE SAMPLE. The symbol 50/11 indicates that 50 blows of a 140 pound hammer falling 30 inches were required to drive a 2.0 inch O.D. sampler 11 inches. 1. The exploratory borings were drilled on August 18, 19, and 20, 2009. Exploratory boring TH -3 was drilled using a 4 -inch diameter continuous flight power auger mounted on a tracked drill rig. Exploratory borings TH -1, TH -2, TH -4, and TH -5 were drilled using a percussion down -hole hammer technique. 2. Ground water was encountered at the time of drilling in exploratory boring TH -3 at a depth of 9.0 feet. Ground water was not encountered in exploratory boring TH -1 to the maximum depth of 20.0 feet, and in borings TH -2, TH -4, and TH -5 to the maximum depth explored of 40.0 feet. 3. The Logs of Exploratory Borings are subject to the explanations, limitations, and conclusions as contained in this report. 4. Laboratory Test Results: WC - Indicates natural moisture ( %) DD - Indicates dry density (pcf) -200- Indicates percent passing the No. 200 sieve ( %) LL - Indicates liquid limit ( %) PI - Indicates plasticity index ( %) CL- Indicates water soluble chloride concentration (ppm) Ss- Indicates soluble sulfate concentration (ppm) pH - Indicates pH RES - Indicates resistivity (OHM -cm) 5. Approximate elevations for exploratory borings are based on interpreting the elevations after locating the exploratory borings on the topographic maps provided by the Town of Vail. LEGEND OF EXPLORATORY BORINGS JOB NO. 09 -048 FIG. 6 KOECHLEIN CONSULTING ENGINEERS 100 0 90 90 10 80 10 80 20 70 20 0 70 O 30 z 30 z m co m � so 40 40 m <a 40 m z F so 1— so 50 M z w so � z M 40 m D (f D 40 0 w a 80 W a 60 z m z m 30 v 30 70 70 20 20 80 80 10 10 90 0 90 0 1100 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM 100 COBBLES 200 100 10 1 0.1 0.01 0.001 SAND SILT DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of SAND, Gravelly, Some silt GRAVEL 39 % SAND 49 % Source TH -1 Sample No. Elev. /Depth 0.3 -5.0 feet SILT & CLAY 12 % LIQUID LIMIT NL % PLASTICITY INDEX NP % a' 100 0 90 10 80 20 70 O 30 z m � so 40 m 1— so so � z m D 40 0 w a 60 z m 30 70 20 80 10 90 0 1100 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of FILL, Sand, Gravelly, Silty GRAVEL 27 % SAND 54 % Source TH -2 Sample No. Elev. /Depth 4.0 feet SILT & CLAY 19 % LIQUID LIMIT NL % PLASTICITY INDEX NP % GRADATION TEST RESULTS Job No. 09 -034 FIG. 7 KOECHLEIN CONSULTING ENGINEERS 100 0 10 90 80 20 30 70 (7 z 30 70 Z 60 m � 40 i 60 u a � 40 N a a M � 50 1.- 50 w m z -i 50 50 Wm ;0 60 D E 40 w a , 60 D 40 � w 0 z m p 70 30 z m 70 p 30 80 20 80 20 10 90 10 - 1 90 p 0 77- 100 100 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL COBBLES GRAVEL SAND SILT CLAY Sample of SAND, Gravelly, Silty GRAVEL 14 % SAND 64 % Source TH -2 Sample No. Elev. /Depth 20.0 feet SILT & CLAY 22 % LIQUID LIMIT % PLASTICITY INDEX % #143 #200 100 0 10 90 80 20 30 70 (7 z m � 40 i 60 u a M � 50 1.- 50 w ;0 60 D E 40 w a z m p 70 30 80 20 10 - 1 90 p 77- 100 __ 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of SAND, Gravelly, Silty GRAVEL 20 Source TH -3 Sample No. Elev. /Depth 9.0 feet SILT & CLAY 14 PLASTICITY INDEX GRADATION TEST RESULTS • SAND 66 % • LIQUID LIMIT % Job No. 09 -034 FIG. 8 KOECHLEIN CONSULTING ENGINEERS 100 0 90 10 10 80 80 20 20 70 C7 70 30 z CO 30 z m ;U so a m 6o � 40 n Z ao m <a --I 50 50 Z w z 50 M m 40 50 z LU D m 60 W a *C D 40 � W a Z m 60 Z M v 30 70 30 20 70 80 20 10 80 90 0 10 H Li 100 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of FILL, Sand and gravel, Silty GRAVEL 39 % SAND 40 % Source TH -4 Sample No. Elev. /Depth 4.0 feet SILT & CLAY 21 % LIQUID LIMIT % PLASTICITY INDEX % 100 0 90 10 80 20 70 30 z m 6o � ao m <a z 50 50 z LU m D 40 � W a 60 Z M 30 70 20 80 10 H Li 90 0 too 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of SAND, Gravelly, Some silt GRAVEL 36 Source TH -4 Sample No. Elev. /Depth 30.0 feet SILT & CLAY 11 PLASTICITY INDEX GRADATION TEST RESULTS • SAND 53 % • LIQUID LIMIT % Job No. 09 -034 FIG. 9 KOECHLEIN CONSULTING ENGINEERS 100 0 10 90 80 20 30 70 (7 z 60 m ;0 40 M z 50 1.- 50 w D of 40 w a 60 z m 70 p 30 80 20 10 90 p 100 200 100 10 1 0.1 0.01 0.001 DIAMETER OF PARTICLE IN MM COBBLES GRAVEL SAND SILT CLAY Sample of SAND, Gravelly, Some silt GRAVEL 41 % SAND 46 % Source TH -5 Sample No. Elev. /Depth 24.0 feet SILT & CLAY 13 % LIQUID LIMIT % PLASTICITY INDEX % Sample of Source Sample No. Elev. /Depth GRAVEL % SAND % SILT & CLAY % LIQUID LIMIT % PLASTICITY INDEX % GRADATION TEST RESULTS Job No. 09 -034 FIG. 10 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers CONCRETE FOOTING '� is 1 1 EXISTING 1 EXISTING FILL COMPACTED FILL \ FILL (SEE REPORT FOR COMPACTION RECOMMENDATIONS) - =1 I I -1 I I -1 I I-1 I I -1 11= - -1 I 1 =1 I I =11 I- FIRM NATURAL SOIL EDGE OF EXCAVATION (EXCAVATE AS PER OSHA REGULATIONS) FOUNDATION EXCAVATION RECOMMENDATIONS JOB NO. 09 -034 FIG. 11 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers CLAYEY BACKFILL 10 - COMPACTED BACKFILL 11 Y BELOW GRADE WALL EDGE OF EXCAVATION (EXCAVATE AS PER OSHA REGULATIONS) MANUFACTURED WALL DRAIN FILTER FABRIC GRAVEL 12" PERFORATED PIPE NOTES: WATERPROOFING OR DAMPPROOFING `PLASTIC SHEETING 12" MIN. 1. DRAIN SHOULD BE AT LEAST 12 INCHES BELOW TOP OF FOOTING AT THE HIGHEST POINT AND SLOPE DOWNWARD TO A POSITIVE GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING. 2. EXCAVATIONS ADJACENT TO FOOTINGS SHOULD BE CUT AT A 1 TO 1 (HORIZONTAL TO VERTICAL) OR FLATTER SLOPE FROM THE BOTTOM OF THE FOOTINGS. EXCAVATIONS ADJACENT TO FOOTINGS SHOULD NOT BE CUT VERTICALLY. 3. THE DRAIN SHOULD BE LAID ON A SLOPE RANGING BETWEEN 1/8 INCH AND 1/4 INCH DROP PER FOOT OF DRAIN. 4. GRAVEL SPECIFICATIONS: WASHED 1.5 INCH TO NO. 4 GRAVEL WITH LESS THAN 3% PASSING THE NO. 200 SIEVE. 5. THE BELOW GRADE CONCRETE FOUNDATION WALLS SHOULD BE PROTECTED FROM MOISTURE INFILTRATION BY APPLYING A SPRAYED ON MASTIC WATERPROOFING, DAMPPROOFING, OR AN EQUIVALENT PROTECTION METHOD. TYPICAL WALL DRAIN DETAIL JOB NO. 09 -034 FIG. 12 FLOOR NOTES: KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers EARTH PRESSURE --- 45H 0.2 H 0. iH f 0.2 H I 1. THIS PRESSURE DIAGRAM IS APPLICABLE FOR BRACED WALLS THAT ARE GREATER THAN 15 FEET IN HEIGHT WITH NO HYDROSTATIC PRESSURE. 2. THE PRESENCE OF A FLOOR SYSTEM IN BELOW GRADE LEVELS CREATES A BRACED EXCAVATION CONDITION. 3. THE BELOW GRADE WALLS SHOULD BE PROTECTED FROM MOISTURE INFILTRATION BY APPLYING A SPRAYED ON MASTIC WATERPROOFING OR AN EQUIVALENT PROTECTION METHOD. 4. THE LATERAL EARTH PRESSURE DIAGRAM ASSUMES THAT THE WALLS ARE PROPERLY DRAINED AND NO HYDROSTATIC PRESSURE CAN DEVELOP AGAINST THE WALLS. TRAPEZOIDAL LATERAL EARTH PRESSURE (BRACED WALLS - DEWATERED) JOB NO. OM34 FIG. 13 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers CLAYEY 7:7111=11 10 MANUFACTURED — ■ WALL DRAIN EDGE OF EXCAVATION (EXCAVATE AS PER OSHA REGULATIONS) FILTER COMPACTED BACKFILL 11 1,,— RETAINING WALL L PERFORATED PIPE i 101 "MIS WATERPROOFING/ DAMPPROOFING 1. DRAIN SHOULD BE SLOPED DOWNWARD TO A POSITIVE GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING. 2. THE DRAIN SHOULD BE LAID ON A SLOPE RANGING BETWEEN 1/8 INCH AND 1/4 INCH DROP PER FOOT OF DRAIN. 3. GRAVEL SPECIFICATIONS: WASHED 1.5 INCH TO NO. 4 GRAVEL WITH LESS THAN 3% PASSING THE NO. 200 SIEVE. 4. THE BELOW GRADE CONCRETE RETAINING WALLS SHOULD BE PROTECTED FROM MOISTURE INFILTRATION BY APPLYING A SPRAYED ON MASTIC WATERPROOFING /DAMPPROOFING OR AN EQUIVALENT PROTECTION METHOD. TYPICAL RETAINING WALL DRAIN DETAIL JOB NO. 09 -034 FIG. 14 H a E-� W H W W W Q a w O C6 of w w z z w IIIIIIIIIIIIIII �II�I 111�9i ■II�111111� II ■IIIIIIIIIIIIIIII C6 of w w z z w September 10, 2009 Job No. 09 -034 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers APPENDIX A PAVEMENT DESIGN CALCULATIONS FLEXIBLE PAVEMENT DESIGN DATA DESIGN DATA Traffic Load - EDLA = 10 Traffic Load - 18 kip ESAL's = 7,300 Design Life = 20 Subgrade Soil Classification = A -1 -b Assumed "R" Value = 50 Soil Support Value - S, = 7.0 Resilient Modulus - MR (psi) = 13,168 Reliability - R ( %) = 90 Serviceability Index - SI = 2.5 Serviceability Loss - PSI = 2.0 Overall Deviation - So = 0.44 DESIGN CALCULATION RESULTS Based on the following equation: log,o(18k ESAL) = ZRxS,,+9.36xlogio(SN +1) -0.20 +log,o( PSI /(4.2- 1.5))/(0.4 +( 1094 /(SN +1)5'19)) +2.32xlog,AMR) - 8.07 Structural Number - SN = 1.8 PAVEMENT THICKNESS DESIGN EQUATION SN = C,D, +C2D2m2 where C, = Strength Coefficient - Asphalt = 0.44 1112 = Drainage Coefficient = 1.0 D, = Depth of Asphalt (inches) D2 = Depth of Roadbase (inches) PAVEMENT THICKNESS RESULTS Full Depth Asphalt D, = 5.0 inches Asphalt + Aggregate Base Course D, (Asphalt) = 4.0 inches D2 (Aggregate Base Course) = 6.0 inches JOB NO. 09 -034 FIG. A -1 RIGID PAVEMENT DESIGN DATA DESIGN DATA Traffic Load - EDLA = 10 Traffic Load - 18 kip ESAL's = 7,300 Design Life = 20 Subgrade Soil Classification = A -1 -b Assumed Modulus of Subgrade Reaction - k (psi /in) = 150 Modulus of Rupture - S'c (psi) = 650 Modulus of Elasticity - Ec (psi) = 3,400,000 Drainage Coefficient - Cd = 1.0 Load Transfer Coefficient - J = 4.2 Reliability - R ( %) = 90 Serviceability Index - SI = 2.0 Overall Deviation - So = 0.34 DESIGN CALCULATION RESULTS Based on the following equation: loglo(18k ESAL) = ZRxS,,+7.35xloglo(D +1) -0.60 +logio(PSI/(4.5- 1.5))/(1.0 +(1.624x 107) /(D +l )8'46)) +(4.22- 0.32xp,)x(log,o[(Sc' xCDx(Do.7s_ 1.132))/((2l 5.63xJx(D0.75- (18.42 /(E,/k)0z5))))] PAVEMENT THICKNESS RESULTS Rigid Pavement Thickness D = 5.0 inches JOB NO. 09 -034 FIG. A -2 September 10, 2009 Job No. 09 -034 APPENDIX B KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers PAVEMENT CONSTRUCTION RECOMMENDATIONS KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers FLEXIBLE PAVEMENT CONSTRUCTION RECOMMENDATIONS Experience has shown that construction methods can have a significant influence on the life and serviceability of a pavement system. We recommend the proposed pavement be constructed in the following manner: Where the subgrade soils do not satisfy the compaction requirements, they should be scarified, moisture treated, and recompacted. Soils should be compacted as specified in the COMPACTED FILL section of this report. 2. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. Fill should be compacted as specified in the COMPACTED FILL section of this report. 3. After final subgrade elevation has been reached and the subgrade compacted, the area should be proof - rolled with a heavy pneumatic tired vehicle (i.e., a loaded 10 -wheel dump truck). Subgrade that is pumping or deforming excessively should be removed and replaced. 4. If areas of soft or wet subgrade are encountered, the material should be overexcavated and replaced. Suitable structural fill may be used. Where extensively soft, yielding subgrade is encountered, we recommend the excavation be inspected by a representative of our office. 5. Aggregate base course should be laid in loose lifts not exceeding 6.0 inches, moisture treated to within 2.0 percent of the optimum moisture content, and compacted as specified in the COMPACTED FILL section of this report. 6. The aggregate base course may consist of processed recycled asphalt. The recycled asphalt base course should meet the gradation requirements of CDOT Class 5 or Class 6 base course. The recycled asphalt base should be laid in loose lifts not exceeding 6.0 inches, moisture treated and compacted as specified in the COMPACTED FILL section of this report. 7. Asphaltic concrete should be plant -mixed material. Superpave material should be compacted to between 92 and 96 percent of the maximum theoretical density and other asphalt material to at least 95 percent of the maximum Marshall value. The subgrade preparation and the placement and compaction of all pavement layers should be observed and tested. Compaction criteria should be met prior to the placement of the next paving lift. JOB NO. 09 -034 FIG. B -1 KOECHLEIN CONSULTING ENGINEERS, INC. Geotechnical and Materials Engineers RIGID PAVEMENT CONSTRUCTION RECOMMENDATIONS Rigid pavement sections are not as sensitive to subgrade support characteristics as flexible pavement. Due to the strength of the concrete, wheel loads from traffic are distributed over a large area and the resulting subgrade stresses are relatively low. The critical factors influencing the performance of a rigid pavement are the strength and quality of the concrete, and the uniformity of the subgrade. We recommend subgrade preparation and construction of the rigid pavement section be completed in accordance with the following recommendations. 1. Where the subgrade soils do not satisfy the compaction requirements, they should be scarified, moisture treated, and compacted. Soils should be compacted as specified in the COMPACTED FILL section of this report. 2. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. Fill should be compacted as specified in the COMPACTED FILL section of this report. 3. The resulting subgrade should be checked for uniformity and all soft or yielding materials should be replaced prior to paving. This should be done by proof - rolling with a heavy pneumatic tired vehicle (i.e., a loaded 10 -wheel dump truck). Concrete should not be placed on soft, spongy, frozen, or otherwise unsuitable subgrade. 4. Subgrade should be kept moist prior to paving. 5. Curing procedures should protect the concrete against moisture loss, rapid temperature change, freezing, and mechanical injury for at least 3 days after placement. Traffic should not be allowed on the pavement for at least one week. 6. A white, liquid membrane curing compound, applied at the rate recommended by the manufacturer, should be used. 7. Construction joints, including longitudinal joints and transverse joints, should be formed during construction or should be sawed shortly after the concrete has begun to set, but prior to uncontrolled cracking. All joints should be sealed. 8. Construction control and inspection should be carried out during the subgrade preparation and paving procedures. Concrete should be carefully monitored for quality control. JOB NO. 09-034 FIG. B -2