Vehicle Impact on the Deck Slab of Concrete Box-Girder Bridges due to Damaged Expansion Joints

Abstract

Expansion joints will experience increasing deterioration and damage under repeating vehicle loading. A severely damaged expansion joint will induce significant dynamic vehicle load effects on the bridge deck near the expansion joint, whereas it may not cause such a large effect on the global bridge responses, e.g., deflection and bending moment at the bridge midspan. The impact factors (IMs) in bridge design codes are usually determined from global bridge responses. Therefore, it may be inappropriate to use the IMs in bridge design codes for the design of deck slabs for which the transverse bending moment is usually the controlling internal force. In this study, a three-dimensional vehicle-bridge model is used to study vehicle impact on the deck slab of prestressed concrete box-girder bridges caused by damaged expansion joints. Results show that the damage condition of expansion joints has a significant effect on the vehicle impact on the bridge deck slab, whereas it has a limited effect on the global bridge responses, especially for long bridges. The relationships between the vehicle impact on the deck slab and a few important parameters are also investigated, and some useful conclusions are obtained.