Effect of Environmental Conditions and Structural Design on Linear Cracking in Virginia Bridge Decks

Abstract

EFFECT OF ENVIRONMENTAL CONDITIONS AND STRUCTURAL DESIGN ON LINEAR CRACKING IN VIRGINIA BRIDGE DECKS <p> Wesley John Keller <p> Abstract <p> Chloride-induced corrosion of reinforcing steel is widely accepted as the primary cause of premature deterioration in concrete bridge decks (Brown, M.C., 2002). Since linear cracking in concrete cover can potentially accelerate chloride ingress to the depth of the reinforcing steel, there is reason to believe that severity of deck cracking can significantly influence the time to first repair and/or rehabilitation of the bridge deck. <p> Surface width, orientation, and length of cracks in 38 Virginia bridge decks were investigated in order to characterize the general distribution of deck cracking in the commonwealth of Virginia. Crack data was correlated to structural/material design parameters and environmental exposure conditions in order to determine significant predictor-response relationships. The majority of surveyed bridge decks were divided into four classifications of deck type based on superstructure type and construction era, either 1968-1971 or 1984-1991. Surveyed bridge decks that did not fit into any of the four classifications were used to form more generalized subsets. These larger subsets were used to determine if significant influence factors could be translated to broader classifications of bridge decks. <p> Transverse beam spacing, annual average daily truck traffic (AADTT), resistivity of the deck concrete, chloride exposure, and the percentage of concrete clear cover depths less than or equal to 38mm (1.5in) were all determined to have a significant correlation with linear deck cracking.