Skip to main content


Project Type
UTRC Research Initiative
Project Dates
12/31/2007 - 12/31/2009
Principal Investigators
Project Status

The challenge to minimizing or eliminating deck cracking is the contradiction between the flexibility needed to accommodate shrinkage strains and the stiffness/bonding required to provide full composite action. It is possible to achieve both of these contradicting goals through the use of controlled composite action (C2A) connectors for the deck-girder system. The innovative design mechanism controls composite action by preventing it during early ages (i.e., to allow for unrestraint crack free concrete shrinkage) while it is activated for higher service load and under ultimate loading condition. To achieve this objective (i.e., no composite action initially and full composite action ultimately) it is proposed that the shear connectors be wrapped in a hyper-elastic (rubber like) material of carefully designed thickness. Under low level of stresses the hyper-elastic material does not provide any resistance and deforms easily allowing for unrestraint shrinkage of concrete deck. Subsequent to initial straining due to shrinkage, the hyper-elastic material will develop high level of resistance and will fully engage the shear studs, thus, providing full composite action.

Tens of thousands of bridges in the US develop transverse deck cracking due to concrete shrinkage. Transverse cracks are observed on various types of superstructures and in most geographical locations. They increase the maintenance cost, reduce bridge life span through acceleration in reinforcement corrosion, and due to leakage of water through superstructure damage bridge substructure and affect bridge aesthetics. Thus, the life-cycle design feature of the proposed concept will have significant impact on durability and maintenance of highway bridges with enormous cost saving benefits with practically no initial cost.