Agenda - Council - 11/26/2024 - Laserfiche WebLink

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replace all curb in gutter in the reconstruction area between Sunfish Lake Boulevard and Nowthen Boulevard compared to spot repairs. Alpine Drive between Nowthen Boulevard and Saint Francis Boulevard(TH 47) is a combination of 44-foot-wide urban and rural section with an 8-foot bituminous trail on the south side of the street, and an 8-foot bituminous trail between Krypton Street and TH 47 on the north side of the street. The Anoka County signal upgrade at Nowthen Boulevard from 2024, including turn lanes for westbound Alpine Drive, reconstructed approximately 740 linear feet of Alpine Drive east of Nowthen Boulevard(generally to Krypton Street). This was found to generally be in good condition,with only refreshing of the pavement markings proposed in this section of Alpine Drive. The ADT for this segment of Alpine Drive is 2,500. Review of the geotechnical report found clean sands, ideal for both utility and pavement support. The total project length of Alpine Drive between Sunfish Lake Boulevard and TH 47 is approximately 1.02 miles. Alpine Drive is an MSA street and must meet MSA 10-ton pavement strength design requirements. To achieve this, staff is proposing to place 4.5-inches new bituminous over 5-inches aggregate base (9.5-inch total pavement section). The pavement cores produced as part of the geotechnical report found approximately 5-inches of bituminous over 4.5-inches aggregate base, which will allow the project to be built without additional subsoil excavation to achieve the proposed pavement section. The western 460 linear feet is proposed to only receive a 2-inch mill and overlay. Approximately 750 linear feet adjacent to the wetlands west of Nowthen Boulevard are proposed to be raised,which will require replacement of the concrete curb and gutter. Additionally, Staff will be reviewing the cost-effectiveness of replacing all concrete curb and gutter west of Nowthen Boulevard(in the areas proposed to be reconstructed). The section of Alpine Drive approximately 660 linear feet west and 460 linear feet east of Nowthen Boulevard is not proposed to receive a bituminous treatment, only refreshing the existing pavement markings. The remaining pavement, generally between Krypton Street and TH 47 is proposed to be reconstructed using the FDR method with only spot curb and gutter repairs. Bituminous trail exists throughout the project area, including on both sides of Alpine Drive for approximately half the project. In general, the bituminous trail is functional,but has deteriorated to a point where improvements to the trail are recommended. Staff is proposing to include reconstruction of the bituminous trail and associated pedestrian ramps as an alternative bid. In total there is approximately 7,600 linear feet of 8-foot bituminous trail within the project area. Replacement of this trail is not included within the CIP. Staff believes the majority of the trail should qualify for MSA funding if desired,but will look further into potential funding sources as part of the project design process. Staff estimates construction costs for the trail replacement at$250,000. Staff has identified an unmarked crossing at Sodium Street, connecting the Alpine Acres subdivision with the Fox Knoll subdivision to the south. Alpine Drive is a 45 mph(high speed)road, staff does not support a crossing at this location and is proposing to remove the pedestrian ramp on the south side of Alpine Drive with this project. The bituminous trail continues west to Sunfish Lake Boulevard which provides safe crossings, including crossing westbound to Alpine Park; the most likely destination for local trail users in this region of the City. Additionally, a marked mid-block crossing exists between Nowthen Boulevard and Helium Street, and a marked crossing exists at Helium Street. Staff is proposing to eliminate both of these marked crossings as part of this project,primarily due to Alpine Drive being a high speed(45 mph) street and safe signalized crossings located at traffic signals at both County and MnDOT roads. Watermain, sanitary sewer, and storm sewer exist throughout the project area. The only known utility improvements include storm sewer located in the wetland area west of Nowthen Boulevard. Two corrugated metal pipe(CMP) culverts are proposed to be upgraded to reinforced concrete pipe(RCP). In addition,two sets of storm sewer inlets and outlets to the wetlands exist in this stretch. By raising the roadway, at a minimum the catch basin castings will need to be adjusted,but may need to be replaced depending on how high the road is raised. Any additional repairs will not be known until the sewer televising reports are reviewed. If repairs are required, they will be included within the final plans,unless staff determines the repair needs are imminent. Additional Permitting Alpine Drive is an MSA street,which requires review and approval by the MnDOT MSA department prior to bidding the project. Because the project goes up to both the Anoka County and MnDOT right-of-way's, and will