Structural Design Actions to Mitigate Bridge Deck Cracking

Abstract

A design consideration that probably receives too little attention in bridge design and in concrete mixture design as well, is durability. One of the primary factors affecting concrete bridge durability is cracking. This cracking results primarily from thermal and drying shrinkage and from static and dynamic truck loadings. Structural designers have greater control of the ultimate cracking and durability performance of bridges than any other group. Specific actions are recommended in this article for the consideration of structural designers to mitigate concrete cracking and thus to enhance bridge durability. Most of the actions pertain to the deck, which is the bridge component that typically exhibits the greatest deterioration rate. An example illustrates dramatic improvements in bridge deck performance in the transverse direction for only a 2.54 cm (1 in.) increase in thickness. In the longitudinal direction, a 2.54 cm (1 in.) deck thickness increase also results in significant beneficial effects.