Agenda - Council - 01/13/2015 - Laserfiche WebLink

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4.PROPOSED IMPROVEMENTS 4.1Streetand Stormwater Improvements 4.1.1Garnet Street Garnet Street is proposedto be reconstructedwithbituminous pavement and concrete curb and gutterwhich will better facilitate drainage over time.Numerous streetsexist throughout the City with bituminous curbing and almost all of them are deteriorating more rapidly than streets withconcrete curb and gutterdue to their inability to rapidly convey drainage off of the pavement surface, particularly along edges of streets. Figure 1in Appendix A The proposed surface improvements are shown on . Pathway/Sidewalk: New sidewalksegmentsareproposed to be constructed along the east side of Garnet th Streetto connect to existing concrete sidewalks located along the north side of 167 Avenue at the south end of the project, and along the east side of Garnet Streetat the north end of the project, both of which are immediately available at the project termini. Figure 2in Appendix A. Existing pedestrian facilities are shown on StreetDesign: Garnet Streetis currently an urban residential street with bituminous curb and pavement 31 feet in width from back-of-curb to back-of-curb.Existing and proposed traffic counts are consistent with typical residential streets. Garnet Street is proposedto be reconstructedmaintaining its current width of 31 feet from back-of-curb to back-of-curb. NTI recommends a pavement section of 6” class 5 aggregate base, 2” bituminous base course, and 1½” bituminous wear course. However, the City’s standard residential street pavement section is 4” class 5 aggregate base, 2” bituminous base course, and 1½” bituminous wear course. Based on the low traffic volumes on these streets, staff recommends using the City’s standard residential street pavement section. NTI recommends completing a12” minimum subgrade correction by scarifying and re- compacting existing poor subgrade soils, then test rolling the corrected soils after and checking for poor or unsuitable areas and making spot corrections as needed. NTI recommends also adding sub-drain pipealong the outside bottom edges of subgrade on all streetsandplugging the drain pipe into storm sewer catch basins.However, NTI also suggests there will be a long-term potential for differential settling of the streetsif the existing subgrade soils are scarified and re-compactedas per their recommendation. Staff is therefore recommending to correctall poor subgradesoilsby excavating 3 feet of existing poor soils and replacing itwith clean imported select granular borrow. This will provide a uniform subgrade section that will not be prone to differential settling over time and will thereforerequireless maintenance over timeto reducethe City’s long-term maintenance costs,and will maximize the life of the street. Feasibility Report th Garnet Street and 168Avenue Reconstruction City of RamseyProject No. 13-10 Page 9