Evaluation of Deck Durability on Continuous Beam Highway Bridges

About the report:

In an effort to determine the extent of deck cracking on continuous steel beam bridges and the effect of the cracking on deck durability, 137 structures were visually inspected and 5 of these were selected for detailed evaluation. The general survey disclosed widespread transverse cracking throughout the lengths of the continuous beam sections in both the positive and negative moment areas. The cracking appeared to propagate, as the spans vibrated, from short pattern cracking probably caused by differential subsidence of the plastic concrete over the reinforcing steel and plastic shrinkage of the slab. Detailed deck evaluations, which included half-cell potential measurements and chloride content determinations, disclosed that chlorides were present in the cracks to a significantly greater degree than in adjacent uncracked concrete. However, sealing the cracks with a low viscosity, low modulus epoxy compound appeared to be effective in limiting the entry of chlorides. In spite of the widespread cracking noted and the presence of chlorides in the cracks, corrosion-induced deck distress was not found to be a widespread problem on continuous span bridges.

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