Agenda - Council - 09/12/2017 - Laserfiche WebLink

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4.1.2 Stormsewer Improvements The existing storm sewer system is in good condition and appears to meet all current State Aid design standards and is therefore not proposed to be improved. The only proposed storm sewer improvements include adjusting and/or repairing catch basin castings as needed. No stormwater quality treatment improvements are required for this project since the street is proposed to be reconstructed at its current width. 4.1.3 Geotechnical Considerations Northern Technologies, Inc. (NTI) completed a Geotechnical Exploration and Engineering Review including eleven (11) soil borings spaced at approximate 200 foot intervals along Sunwood Drive. The locations of the borings are shown in the Boring Location Diagram in Appendix C of NTI's report, attached in Appendix D. NTI recommends completing a full reconstruction with subgrade corrections and the removal and replacement of all concrete curb and gutter. This work would result in project costs approximately twice as much as the current estimate included in this report, and would result in significant site access and traffic impacts during construction. WSB completed four (4) pavement cores along Sunwood Drive as shown in their Pavement Evaluations and Recommendations report, attached in Appendix D. WSB recommends leaving all intact existing curb and gutter in place, which staff estimates accounts for over 80% of the existing curb and gutter, which is only 20 years old. WSB also recommends reconstructing only the aggregate base and bituminous pavement by incorporating additional strength in the aggregate base using a Stabilized Full Depth Reclamation process. In total, this work is estimated to cost half as much as a total reconstruction yet would result in a pavement design life of 30-plus years. In considering that the remaining curb and gutter will likely need to be replaced in 30 to 40 years, a total reconstruction could be evaluated at that time. Another benefit to this design is that it would result in minimal impacts to site access and traffic during construction. 4.1.4 Other Considerations Driveways: Existing driveways will need to be reconstructed to varying degrees. The limits of construction will vary with each driveway based on the elevations of the street and the parking lot, as well as the driveway pavement type. During design, staff will evaluate the construction limits for each driveway and will incorporate this into the plans, but as with all street reconstruction projects the exact limits of construction will be determined in the field during construction. Right -of -entry forms would be obtained from private property owners if work is required outside City right-of-ways and easements. Irrigation Systems: Developed properties along the project corridor may have private irrigation systems. Impacts to these systems may occur where the existing curb and gutter is being replaced. On past street reconstruction projects, the City repaired private irrigation systems that were damaged as part of the project. Staff recommends foregoing this practice on future projects. Instead, staff recommends notifying property owners in writing of the pending Feasibility Report Sunwood Drive Reconstruction City of Ramsey Project No. 17-00 Page 7