Effect of pavement maintenance cycle on the fatigue reliability of simply-supported steel I-girder bridges under dynamic vehicle loading

In this study, the effect of the pavement maintenance cycle on the fatigue reliability of simply-supported steel I-girder bridges under dynamic vehicle loading is studied. The bridge model and the fatigue load model are both adopted from the Load and Resistance Factor Design (LRFD) Bridge Design Specifications of the American Association of State Highways and Transportation Officials (AASHTO). A three-dimensional vehicle-bridge coupled model is developed to simulate the vehicle-bridge interaction and used to obtain the stress ranges of the steel bridge girders under the dynamic vehicle loading. Numerical simulations are carried out to study the influence of three important parameters, including the road surface condition, bridge span length and vehicle speed, on the fatigue damage induced by the fatigue truck. The results from this study show that the bridge fatigue reliability decreases dramatically under repeated dynamic vehicle loads when the road surface condition is very poor and that the pavement maintenance cycle has a significant influence on the bridge fatigue reliability. A procedure for determining the desired pavement maintenance cycle to achieve the target fatigue reliability of steel bridge girders is developed. An example is also provided for demonstrating the proposed procedure.