Agenda - Council - 04/14/2020 - Laserfiche WebLink

Home

4. CONSIDERED IMPROVEMENTS 4.1 Project Area Selection The City's 10-year Capital Improvement Program (CIP) calls for the reconstruction of Variolite Street between Alpine Drive and 173rd Avenue in 2020. The CIP does not include watermain or sanitary sewer improvements. However, the City's 2040 Comprehensive Plan calls for sanitary sewer and watermain improvements north of the existing utilities along Variolite Street. The scope of the proposed improvements is included in Appendix A. 4.2 Street Improvements Variolite Street is proposed to be reconstructed by matching existing widths and elevations between 163rd Lane and 173rd Avenue, with bituminous pavement and ditch sections to carry storm water runoff. Between Alpine Drive and 163rd Lane, Variolite Street is generally proposed to be reconstructed 6-feet narrower than existing, but generally matching existing elevations with bituminous pavement and ditch sections. 4.2. a Stabilized Full Depth Reclamation To meet the required MSA design standards, several pavement sections were considered. Stabilized Full Depth Reclamation (SFDR) was determined to be the most cost-effective method of reconstruction. This process involves reclamation (grinding in -place) of the existing bituminous pavement plus a portion of the underlying aggregate base. Excess reclaimed material is then removed as needed so the new pavement will match into existing shoulders, driveways, and cross streets. Staff is proposing to stabilize the base 1 foot beyond the edges of drive lanes by adding liquid asphalt emulsion into the reclaim material, which is then mixed in, rolled and compacted. Once compacted, the SFDR can be opened up to traffic, and gains strength with the further compaction of vehicle traffic. This project proposes 6-inches of SFDR, with 4-inches of new bituminous pavement placed on top. The City recently completed an SFDR project on Sunwood Drive between Ramsey Boulevard and Bunker Lake Boulevard. A concern with this process is that the moisture content of the stabilized base must meet a specific range before paving is allowed, therefore rain delays are a possibility. However, similar to the Sunwood Drive project, stabilizing the reclamation allows for a thinner overall pavement section, avoiding the need to excavate below the existing aggregate base to make costly subgrade corrections. Considering that Sunwood Drive was reconstructed in 2017 and is still exhibiting very little cracking, Staff is confident that the SFDR process will provide as long of a life for the new pavement section as a full reconstruction with subgrade corrections would, but at a significantly lower cost. To maximize the existing reclamation volume re -used on site, the cross slope of the road is proposed to be increased from 2-percent to 3-percent, allowing the center profile of the street to be raised approximately 2-inches yet sill tie into existing shoulders, driveways and cross streets. Feasibility Report Variolite Street Reconstruction City of Ramsey Project No. 20-01 6