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

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3. EXISTING CONDITIONS 3.1 Existing Pavement, Soil, and Traffic Conditions. All streets proposed to be improved were constructed in 1981 with bituminous pavement, class 5 aggregate base, and ditches. The streets are generally centered within a 66-foot wide right-of-way. Pavement maintenance treatments applied to the street segments included crack seal and seal coat improvements in 1987, an overlay in 1997, and crack seal and seal coat improvements in 2002 and 2012. 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 both street segments. In September of 2018, City Staff recorded a traffic volume of 54 average annual daily traffic (AADT) on 180th Lane west of TH 47. Since Krypton Street is only accessed by 180th Lane, it can be reasonably stated that Krypton Street would have even less traffic. The speed limit is 30 mph for these street segments. Braun Intertec was employed to complete a Geotechnical Exploration and Engineering Review for this project, which included two (2) soil borings spaced at approximately 600-feet along 180th Lane/Krypton Street, including 1 boring in the cul-de-sac on Krypton Street. The locations of the borings are shown in the Soil Boring Location Map in the Appendix of Braun'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 11 feet below the existing ground surface. There was no groundwater observed during the soil borings. Based on the work proposed and the lack of groundwater at a depth of 11 feet below the existing ground surface, groundwater is not anticipated to be encountered during work completed with this proposed project. The soil borings generally indicate the existing bituminous pavement thickness ranges between 4 to 5 inches, and aggregate base thickness is 5 inches. The subgrade generally consists of silty sand, lean clay with sand, and lean clay. This lean clay layer varies from 2 to 9 feet below existing ground. Poorly graded sand was found below the lean clay layer at 4 to 9 feet below existing ground and generally extends to the bottom of the borings (11 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 4.3 inches, and a median aggregate base thickness of 4.1 inches. The median street pavement and base section thickness was 8.2 inches, with a minimum section of 6.1 inches located on 180th Lane, 111 feet west of the intersection with Trunk Highway 47. Feasibility Report Ford Brook Estates Street Reconstructions City of Ramsey Project No. 19-01 7