Impact Factors of Simply Supported Prestressed Concrete Girder Bridges due to Vehicle Braking

Abstract

Much research has been conducted to study the dynamic impact of simply supported bridges due to vehicles moving at constant speeds, whereas only a few studies have focused on the impact due to vehicles changing speed on bridges. Previous numerical studies have shown that the impact factors due to vehicle braking may exceed those prescribed in the bridge design codes. However, most researchers adopted simple vehicle and bridge models that were not able to consider the spatial effect of real bridges and may have overestimated the actual impact factors due to vehicle braking. In this study, a three-dimensional vehicle–bridge coupled model was developed to study the dynamic impact factors of simply supported prestressed concrete girder bridges due to vehicle braking. Impact factors for different bridge responses were studied, including deflection, bending moment, and shear. The results showed that the impact factors due to vehicle braking could be notably larger than those due to the vehicles moving at constant speeds and could exceed the impact factor specified in the AASHTO bridge design code.