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HomeMy WebLinkAboutB12-0356 REV3 LSD ASI 1 (1) 123 North College Avenue, Suite 206 Fort Collins, CO 80524 Phone: (970) 449-4100 Fax: (970) 449-4101 Architect's Supplemental Instructions Project Ford Park Phase I Improvements Owner Town of Vail Todd Oppenheimer 530 South Frontage Road E Vail, CO 81657 From Logan Simpson Design, Inc Kurt Friesen 123 North College Avenue, Suite 206 Fort Collins, CO 80524 970.449.4100 To R.A. Nelson Mike Kowalski 51 Eagle Road #2 Avon, CO 81620 970.949.5152 Architect's Supplemental Instruction NO: 001 Date of Issuance 10/01/2012 Contract For General Construction Contract Date Project Number 125315 Description: 1. Concrete Pavement Jointing Plan (Sheets 1 – 4): Sheets submitted per Owner request to assist Contractor with concrete pavement joint layout and construction. 2. Concrete Pavement Thickness Sheet LS201: Per Owner request, the Concrete Walk, Concrete Paver, Paver Edge Restraint, Asphalt Walk Details have been modified to increase the concrete thickness per recommendations from Ground Engineering. Revised details are attached. 3. Concrete Pavement Sub grade preparation: A Geotechnical Report from Ground Engineering provides 4. East Betty Ford Way Plan and Profile Sheet C201: No revised drawing issued. Shift drain basin from station 15+66.78 to 15+73.59 and grate elevation 8211.11. 5. Raw Water Sheet C620: Sheet to be removed from drawing set. 6. Raw Water Sheet C621: Sheet modified to route raw water along retaining wall footer. Three-inch HDPE material revised to (1) 2-inch PE and (1) 3-inch PE tubing. Existing pipe configuration modified within meter vault to accommodate adjacent retaining wall footing. 7. Raw Water Sheet C622: Sheet modified per revised raw water routing. Solid steel sleeve added for crossing of East Betty Ford Way. 123 North College Avenue, Suite 206 Fort Collins, CO 80524 Phone: (970) 449-4100 Fax: (970) 449-4101 8. Water Sheet C610: Sheet revised to remove all references to C909 PVC and cathodic protection. All water mains and fire hydrant laterals to be DIP. Revise playground restroom meter size, and pipe size / alignment. 9. Water Sheet C611: Sheet revised to remove all references to C909 PVC and cathodic protection. All water mains and fire hydrant laterals to be DIP. 10. Water Sheet C612: Sheet revised to remove all references to C909 PVC and cathodic protection. All water mains and fire hydrant laterals to be DIP. Add note to reconnect VRD building water service. Revise note to require abandonment of existing main, as opposed to removal. Revise existing concessions service to be permanently abandoned at a time as selected by the Owner. 11. Water Sheet C613: Sheet revised to remove all references to C909 PVC and cathodic protection. All water mains and fire hydrant laterals to be DIP. Proposed fire hydrant location and associated lateral alignment revised. 12. Sanitary Sewer Sheet C712: Sheet revised to accommodate sanitary sewer connection as located in the field. 13. Sanitary Sewer Sheet C711: Provide at least one piece of 20-ft C900 PVC pipe centered over revised playground restroom water service location. 14. Details Sheet C900: Revise EBFW Inlet detail to include minimum 2.0% pipe slope and overall structure depth of 3.0 feet from top of grade to invert of outfall pipe. 15. East Betty Ford Way Revised Grading & Planting. The grading, electric manhole elevations and planting have been updated along East Betty Ford Way. See attached drawings for revisions. Attachments: LSASI1_SANITARY PLAN AND PROFILE LSASI1_CONCRETE PAVEMENT JOINTING LSASI1_RAW WATER PLAN LSASI1_WATER PLAN AND PROFILE LSASI1_CONCRETE PAVER DETAIL LSASI1_CONCRETE CURB DETAIL LSASI1_ASPHALT WALK DETAIL LSASI1_PAVER EDGE RESTRAINT DETAIL LSASI1_EBFW GRADING NEAR MEMORIAL LSASI1_EBFW PERENNIAL COUNT REVISED LSASI1_EBFW PLANTING PLAN FOR AREA BEHIND MEMORIAL LSASI1_EBFW REVISED PLANT SCHEDULE FOR AREA BEHIND MEMORIAL LSASI1_EBFW GRADING_AMPHITEATER WALL CONNECTION Ground Engineering Geotechnical Report - Access Road Pavement Section Civil CAD base files Issued by: Kurt Friesen, Senior Associate 10/01/2012 ____________________ _____________________________ _________________ (Signature) (Printed Name and Title) (Date) 379 Indian Road, Grand Junction, CO 81501 Phone (970) 242-4300 Fax (970) 242-4301 www.groundeng.com Office Locations: Englewood Commerce City Loveland Granby Gypsum Grand Junction Casper, WY   July 19, 2012 Subject: Access Road Pavement Section, Ford Amphitheater Improvements, Vail, Colorado Job No. 11-6029 Mr. Chad Salli Vail Public Works Department 1309 Elkhorn Drive Vail, CO 81657 Dear Mr. Salli: GROUND Engineering Consultants, Inc. (GROUND) performed a subsurface exploration program to develop geotechnical recommendations for design and construction of the proposed restroom facilities and Canopy Entrance at the Ford Amphitheater Park in Vail, Colorado. Our findings and conclusions were presented in the report, Subsurface Exploration Program, Geotechnical Recommendations, Ford Amphitheater Improvements, Vail, Colorado, Job No. 11-6029, prepared for the Vail Valley Foundation, dated December 30, 2011. We understand that the access roadway to the site will be improved and that pavement section recommendations have been requested. Evaluation of the access road alignment subgrade was not included in our scope of services. Therefore, the pavement section provided herein is based on extrapolation of the data available from the test holes drilled for our December 30, 2011, report and our experience in the general project area. It should be considered preliminary. We recommend that the exposed subgrade be evaluated during construction so that the pavement section indicated below can be modified, as appropriate. Additional Geotechnical Recommendations Proposed Ford Park Amphitheater Improvements Job No. 11-6029 Page 2 of 6 Reference is made to our December 30, 2011 report, which contains a description of the surface and subsurface conditions at the site, general geotechnical findings and recommendations, and limitations on our services, which will also apply to GROUND’s conclusions and recommendations provided herein. We consider all recommendations in that report not specifically superseded herein to remain valid. Pavement Section A pavement section is a layered system designed to distribute concentrated traffic loads to the subgrade. Performance of the pavement structure is directly related to the physical properties of the subgrade soils and traffic loadings. Because the project pavements will be maintained by the city, the recommended pavement sections were developed in general accordance with town specifications, the Colorado Department of Transportation (CDOT) and local construction practice. Subgrade Materials Based on the limited results of our field and laboratory studies near the proposed roadway, we estimate the subgrade soils in the area proposed for vehicle traffic to consisted predominantly of non-plastic sand and gravel material classified typically as A-2-4 to A-4 soils in accordance with the AASHTO classification system, with Group Index values of 0. Based on our experience with similar materials, we assumed a resilient modulus of 5,000 psi, corresponding to a R-value of about 20. It is important to note that significant decreases in soil support as quantified by the resilient modulus have been observed as the moisture content increases above the optimum. Therefore, pavements that are not properly drained may experience a loss of the soil support and subsequent reduction in pavement life. Anticipated Traffic Based on information provided by the Town of Vail, anticipated traffic along the access road will be as follows: Light (passenger) vehicles: 80 per day (±); Single-axle trucks: 20 per day (±); and Semi-trailer trucks: 1 per day (±). An equivalent 18-kip, single-axle load (ESAL) value of 27,622 was estimated for a ’20-year,’ flexible pavement using these data and CDOT loading factors. (See the attached sheet.) This ESAL value is equivalent daily load application (EDLA) value of about 4. If the design traffic loading differs signigicantly from the above values, GROUND should be notified to re-evaluate the pavement recommendations below. Additional Geotechnical Recommendations Proposed Ford Park Amphitheater Improvements Job No. 11-6029 Page 3 of 6 Pavement Section The estimated soil resilient modulus and the ESAL value were used to obtain a required structural number for the project pavement. The structural number was then used to develop a minimum pavement section using the DARWin™ computer program that solves the 1993 AASHTO pavement design equation. Pavement parameters and calculations are summarized on the attached sheet. A Reliability Level of 90 percent and a Terminal Serviciability Index of 2.5 were used develop the pavement sections. Structural coefficients of 0.40 and 0.12 were used for hot bituminous asphalt and high quality aggregate base course, respectively. Based on the above parameters, a pavement section of 4 inches of asphalt over 6 inches of aggregate base is indicated. Pavement Materials Asphalt pavement should consist of a bituminous plant mix composed of a mixture of aggregate and bituminous material. Asphalt mixture(s) should meet the requirements of a job-mix formula established by a qualified engineer as well as applicable municipal design requirements. The aggregate base material should meet the criteria of CDOT Class 6 aggregate base course. Base course should be placed in uniform lifts not exceeding 8 inches in loose thickness and compacted in accordance with recommendations in the Project Earthwork section of GROUND’s December 30, 2011, report. Note that where those recommendations may differ from Town of Vail standards for public roadway construction, the Town standards take precedence. The following information is provided based on GROUND’s experience in the area, however, Town of Vail standards for public roadway or utility construction should take precedence. Subgrade Preparation GROUND recommends that shortly before paving, the pavement subgrade be excavated and/or scarified to a depth of at least 12 inches, moisture-conditioned and properly re-compacted. Subgrade preparation should extend the full width of the pavement from back-of-curb to back-of-curb. Proof Rolling Immediately prior to paving, the subgrade should be proof rolled with a heavily loaded, pneumatic tired vehicle. Areas where water that show excessive deflection during proof rolling should be excavated and replaced and Additional Geotechnical Recommendations Proposed Ford Park Amphitheater Improvements Job No. 11-6029 Page 4 of 6 stabilized. Areas allowed to pond prior to paving will require significant re- working prior to proof-rolling. Passing proof-rolling is an additional requirement for pavement subgrade soils; it may be possible for soils to be compacted within the limits noted above and fail proof rolling, particularly in the upper range of recommended moisture contents. Subgrade Stabilization Because of the sandy nature of some of the site soils, they may “pump” or deflect during compaction and proof-rolling if moisture levels are not carefully controlled and achieving a stable platform for paving may be difficult. Chemical stabilization of the pavement subgrade may be necessary. We anticipate that stabilization of subsurface soils with portland cement or lime would be effective. It is not possible to assess subgrade stability reliably on the basis of information during geotechnical exploration or subsequent laboratory testing. It is often our experience that where an existing pavement is removed, the underlying subgrade exhibits instability when subjected to construction and/or traffic loading, even where testing suggests otherwise acceptable moisture contents and density. Therefore, it may be necessary to stabilize the majority of the existing subgrade prior to repaving. This may require reprocessing or chemical stabilization of existing soils or removal and replacement with other site materials or imported soil. A geotechnical engineer should be retained to observe the subgrade condition and stability during the removal process. If additional or more specific information is required, then we suggest additional exploration be performed along the proposed roadway. Drainage and Maintenance The collection and diversion of surface drainage away from paved areas is extremely important to satisfactory performance of the pavement. The subsurface and surface drainage systems should be carefully designed to ensure removal of the water from paved areas and subgrade soils. Where topography, site constraints or other factors limit or preclude adequate surface drainage, pavements should be provided with edge drains to reduce loss of subgrade support. The long-term performance of the pavement also can be improved greatly by proper backfilling and compaction behind curb, gutter, and sidewalk. Additional Geotechnical Recommendations Proposed Ford Park Amphitheater Improvements Job No. 11-6029 Page 5 of 6 Landscape irrigation in planters adjacent to pavements and in “island” planters within paved areas should be carefully controlled or differential heave and/or rutting of the nearby pavements will result. Drip irrigation systems are recommended for such planters to reduce over-spray and water infiltration beyond the planters. Enclosing the soil in the planters with plastic liners and providing them with positive drainage also will reduce differential moisture increases in the surrounding subgrade soils. In our experience, infiltration from planters adjacent to pavements is a principal source of moisture increase beneath those pavements. This wetting of the subgrade soils from infiltrating irrigation commonly leads to loss of subgrade support for the pavement with resultant accelerating distress, loss of pavement life and increased maintenance costs. This is particularly the case in the later stages of project construction after landscaping has been emplaced but heavy construction traffic has not ended. Heavy vehicle traffic over wetted subgrade commonly results in rutting and pushing of flexible pavements, and cracking of rigid pavements. In relatively flat areas where design drainage gradients necessarily are small, subgrade settlement can obstruct proper drainage and yield increased infiltration, exaggerated distress, etc. Also, GROUND’s experience indicates that longitudinal cracking is common in asphalt-pavements generally parallel to the interface between the asphalt and concrete structures such as curbs, gutters or drain pans. Cracking of this type is likely to occur even where the subgrade has been prepared properly and the asphalt has been compacted properly. The anticipated traffic loading does not include excess loading conditions imposed by heavy construction vehicles. Consequently, heavily loaded concrete, lumber, and building material trucks can have a detrimental effect on the pavement. GROUND recommends that an effective program of regular maintenance be developed and implemented to seal cracks, repair distressed areas, and perform thin overlays throughout the life of the pavements. The standard practice in pavement design describes the recommended flexible pavement section as a “20-year” design pavement; however, most pavements will not remain in satisfactory condition without regular maintenance and rehabilitation procedures performed throughout the life of the pavement. Maintenance and rehabilitation measures preserve, rather than improve, the Additional Geotechnical Recommendations Proposed Ford Park Amphitheater Improvements Job No. 11-6029 Page 6 of 6 structural capacity of the pavement structure. Therefore GROUND recommends that an effective program of regular maintenance be developed and implemented to seal cracks, repair distressed areas, and perform thin overlays throughout the lives of the pavements. The greatest benefit of pavement overlaying will be achieved by overlaying sound pavements that exhibit little or no distress. Crack sealing should be performed at least annually and a fog seal/chip seal program should be performed on the pavements every 3 to 4 years. After approximately 8 to 10 years after construction, patching, additional crack sealing, and asphalt overlay may be required. Prior to overlays, it is important that all cracks be sealed with a flexible, rubberized crack sealant in order to reduce the potential for propagation of the crack through the overlay. If actual traffic loadings exceed the values used for development of the pavement sections, however, pavement maintenance measures will be needed on an accelerated schedule. We trust that this provides the information that you needed at this time. If you have any questions, please contact this office. Sincerely, GROUND Engineering Consultants, Inc. Scott W. Richards, P. E. Reviewed by Brian H. Reck, P.G., C.E.G. Attachments: Pavement Section Calculations Tr a f f i c L o a d i n g C a l c u l a t i o n s Jo b N o . 1 2 - 6 0 2 9 18 k i p L o a d i n g s , S . I . = 2 . 5 Eq u i v a l e n t 1 8 k i p A x l e L o a d i n g s Hi g h A v e r a g e M e t h o d Al i g n m e n t : Fo r d A m p h i t h e a t e r A c c e s s R o a d ES A L 18 's Lo n g T e r m T r a f f i c Fl e x i b l e R i g i d Pa v e m e n t P a v e m e n t To t a l V e h i c l e s p e r d a y : 10 1 % B u s e s : 0 0 v e h i c l e s 00 % C o m b i n a t i o n T r u c k s : 0. 9 9 % 0. 9 9 9 9 v e h i c l e s 4, 7 6 1 7 , 4 1 0 % S i n g l e U n i t T r u c k s : 19 . 8 % 19 . 9 9 8 v e h i c l e s 21 , 8 1 0 2 4 , 9 6 4 % C a r s & P i c k u p s : 79 . 2 1 % 80 . 0 0 2 1 v e h i c l e s 1, 0 5 1 1 , 0 5 1 No . O f T r a f f i c L a n e s = 2 To t a l : 27 , 6 2 2 To t a l : 33 , 4 2 5 (t o t a l , b o t h w a y s ) La n e F a c t o r : 0 . 6 0 ED L A : 4 ED L A : 5 De s i g n L i f e ( Y e a r s ) : 20 So u r c e o f T r a f f i c D a t a : To w n o f V a i l Lo a d F a c t o r s pe r 1 0 0 0 V e h i c l e s : Fl e x i b l e Ri g i d Bu s e s 2, 7 3 0 2 , 7 3 0 Co m b i n a t i o n T r u c k s 1, 0 8 7 1 , 6 9 2 Si n g l e - U n i t T r u c k s 24 9 2 8 5 Ca r s & P i c k u p T r u c k s 33 Page 1 1993 AASHTO Pavement Design DARWin Pavement Design and Analysis System A Proprietary AASHTOWare Computer Software Product Network Administrator Flexible Structural Design Module Job No. 12-6029 Access Road Flexible Structural Design 18-kip ESALs Over Initial Performance Period 27,622 Initial Serviceability 4.5 Terminal Serviceability 2.5 Reliability Level 90 % Overall Standard Deviation 0.44 Roadbed Soil Resilient Modulus 5,000 psi Stage Construction 1 Calculated Design Structural Number 2.21 in Specified Layer Design Layer Material Description Struct Coef. (Ai) Drain Coef. (Mi) Thickness (Di)(in) Width (ft) Calculated SN (in) 1 Asphalt 0.4 1 4 -1.60 2 Aggregate Base 0.12 1 6 -0.72 Total ---10.00 -2.32