Assessment and rehabilitation strategies/guidelines to maximize the service life of concrete structures

Abstract

This report presents a spreadsheet tool for evaluating life-cycle maintenance strategies for existing concrete bridge decks that have deteriorated as a result of chloride-induced corrosion. The spreadsheet tool construct a performance curve for existing bridge decks, computse the estimated service life of common treatments for bridge decks such as patching, concrete or asphaltic overlays as well as that of a new deck with epoxy coated bars, conducts a life-cycle cost analysis for common maintenance scenarios, and determines the optimal maximum (tolerable) condition index that minimizes total life-cycle maintenance cost. The life-cycle cost analysis is probabilistic. Also, this report provides a library of alternative life-cycle treatment scenarios and offers distribution functions for estimated unit costs. Both agency and user costs are considered. A case study analysis was conducted using the tool. Findings and conclusions suggest that the least cost maintenance scenario may depend on the choice of discount rate. The most significant findings are that total life-cycle cost (user cost plus agency cost) is a function of the maximum tolerable condition Sm. and that the function can be optimized to find the value of Sm that minimizes the total life-cycle cost.