Agenda - Council - 06/14/2011 - Laserfiche WebLink

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BACKGROUND Routine maintenance is the most economical method for safeguarding the public investment in bituminous paved streets. The bituminous street surface weakens as a result of sunlight exposure, precipitation, freeze /thaw cycles and traffic loading. As a result, the asphaltic components of the bituminous become brittle and susceptible to cracking. Once water is able to penetrate surface cracks into the road base, pavement deteriorates at an accelerating pace. To avoid this rapid deterioration, it is the goal of the City to address the preventative maintenance needs of its street system on a periodic basis. The goal of sealcoating is to restore the imperviousness of the pavement. Eliminating water and pavement oxidation retains the flexibility of bituminous pavement. Sealcoating also adds skid resistance as a secondary benefit. Unlike sealcoats which only preserve the flexibility of the bituminous, an overlay provides additional strength to the pavement structure as well as a like new surface. Streets receive a bituminous overlay when they are no longer able to benefit from a sealcoating operation. The construction and maintenance history of the pavements proposed for the 2011 Street Maintenance Program is presented in Appendix A. The 2011 program consists of six individual projects addressing the maintenance needs on 13,47 miles of City streets. Projects 11 -01 through 11 -04 will address 11.93 miles of City streets, and receive a sealcoat preceded by sealing of cracks having widths that exceed one - quarter inch (1/4 "). Projects 11 -05 and 11 -06 will address 1.54 miles of City streets, and receive a one and one -half inch (1 1/2") bituminous overlay on top of the existing bituminous pavement. Pavement maintenance on Minnesota State Aid (MSA) streets is covered under project 11 -04. 2011 sealcoating projects, 11 -01 through 11 -04, consist of streets that have been recently overlaid, a majority of which were done in 2006. These projects will be assessed under the City's new assessment policy for sealcoating, as explained in the financing section below. 2011 overlay projects, 11 -05, through 11 -08, consist of streets that have been aggregated by subdivision or similar lot sizes and will be assessed per unit. The pavement distress on these proposed projects indicate that additional pavement strength is needed. All streets scheduled for maintenance are shown in Appendix C, the preliminary assessment role. This appendix contains a general mapping of each project and lists all the parcels receiving benefit; noting the number of shares being assessed. All streets proposed for the program have received a preliminary survey by the City Engineer and Public Works Supervisor. A post winter survey will be conducted prior to awarding bids in July. Appropriate project adjustments will be made if any of the scheduled projects are deemed to be inappropriate for sealcoating due to advanced deterioration. 2