Agenda - Council - 11/13/2018 - Laserfiche WebLink

Home

3. EXISTING CONDITIONS 3.1 Existing Pavement, Soil, and Traffic Conditions The streets proposed to be improved were constructed between 1992 and 1994 with approximately 2.5-inches of bituminous pavement, 4-inches of aggregate base, and surmountable concrete curb and gutter. The streets were all constructed to a width of 30-feet from face -of -curb to face -of -curb, and are all centered within a 60-foot wide right-of-way. Pavement maintenance treatments applied to the street segments included crack seal and seal coat improvements in 1998 and 2005. Spot patching has been performed on an as -needed basis, and has been a yearly treatment recently. In 2018, Staff assigned a PASER rating of 2 on all the street segments with the exception of the southern half of Krypton Street, which received a rating of 4. In September of 2018, City Staff recorded a traffic volume of 551 average annual daily traffic (AADT) on 146th Avenue west of Nowthen Boulevard, 284 AADT on 146th Avenue east of Junkite Street, 129 AADT on Helium Street south of Sunwood Drive, and 205 AADT on Krypton Street south of Sunwood Drive. The existing speed limit is 30 mph for these street segments. Northern Technologies, LLC (NTI) was employed to complete a Geotechnical Exploration and Engineering Review for this project, which included ten (10) soil borings spaced evenly along 146th Avenue, Helium Street, and Krypton Street. The locations of the borings are shown in the Soil Boring Location Map in the Appendix of NTI's report, attached in Appendix C. The soil borings provide information on existing bituminous pavement and aggregate base course thicknesses, subgrade soil conditions, existing ground water elevations, and potential issues, which may be encountered during construction. All borings terminated at a nominal depth of 10 feet below the existing ground surface. There was groundwater observed in 1 of 10 borings at an elevation of approximately 854.50, 7 feet below existing ground. Based on the work proposed and the lack of groundwater at a depth of 10 feet below the existing ground surface on 9 of 10 borings, groundwater is not anticipated to be encountered during work completed with this proposed projects. The soil borings generally indicate the existing bituminous pavement thickness ranges between 4 to 5 inches, and aggregate base thickness is 6 inches. The subgrade generally consists of poorly graded sand with silt. This poorly graded sand with silt layer was found below the existing aggregate base and generally extends to the bottom of the borings (10 feet). Braun Intertec was employed to complete a ground penetrating radar (GPR) analysis for the project area, which included driving the GPR equipped vehicle throughout all street segments within the project area. A summary table and charts of the GPR Analysis are attached in Appendix C. The GPR data determined a median bituminous pavement thickness of 2.5-inches, and a median aggregate base thickness of 4.1-inches. The median street pavement and base section thickness was 6.5-inches, with a minimum section of 3.6-inches located on Helium Street, 403 feet south of Sunwood Drive. GPR data was unable to be obtained for 146th Avenue. Feasibility Report Wood Pond Kills & Chestnut Ridge Street Reconstructions City of Ramsey Project No. 19-03 8