Agenda - Council - 01/26/1993 - 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 becomes brittle and susceptible to cracking. Once water is able to penetrate surface crack into the road base, pavement deteriorates at an accelerating pace. To avoid this rapid deterioration, it is the acknowledged goal of the City to address the maintenance needs of its street system at no longer than a seven year interval. The 1993 program addresses the maintenance need of bituminous pavements which last received comprehensive maintenance in 1984 and 1985. The 1993 program consists of two distinct types of pavement maintenance. Projects #93-01 through #93-07 consist of sealcoat operations which will be preceded by spot repairs of isolated failed areas and cracksealing of significant pavement cracks. The sealcoating operation juvenates the pavement by applying liquid bituminous to the weathered surface of the bituminous, and thereby protects the underlying pavement mat from losing its flexibility. Projects #93-08 and #93-09 entail one and one-half inch bituminous overlays of the existing pavements. The overlaying process adds additional pavement strength to the roadway, and provides a new even surface. The streets scheduled for maintenance are illustrated in Exhibit A. All streets proposed for the 1993 program have received a preliminary survey by the city engineer and public work supervisor. A post winter survey will be conducted prior to awarding bids in June. Appropriate project adjustments will be made if Projects 93-01 through 93-07 are deemed to be inappropriate for sealcoating due to advanced deterioration or insufficient pavement structurt . PROJECTS QUANTITIES AND COSTS Table 1 provides a detailed breakdown of street lengths, widths and pavement areas for each project. Individual projects have been delineated such that the majority of the propenies benefitted within each project have similar characteristics. Estimates are also provided for cracksealing material, application rates and city public work department time necessary to provide the patching and preparatory work prior to the cracksealing and sealcoating work which will be performed by competitively bid contracts. The estimated construction costs are contained in Table 2. Previous years low bid and estimated 1993 unit prices for seaIcoating and crack sealing are as follows: 1991 Actual 1992 Actual 1993 Estimated Sealcoating $/Sq Y d .292 .350 .388 Cracksealing $/Lb 0.92 0.833 0.95 The amount of cracksealing material required is highly variable depending upon the number of cracks in the individual pavements. Based upon last year's experience, and a windshield survey of - 1 -