Evaluation of traffic load on bridges based on extreme load effect analysis

The traffic load effects on existing bridges may be quite different from those of design live loads due to various traffic environments. However, the bridge maintenance of in-service bridges are performed to maintain the load carrying capacities that have been aimed at the design stage without considering current traffic environments in the fields. The real traffic conditions on existing bridges may require considerably different load carrying capacities. The target load carrying capacity of an existing highway bridge, therefore, should be determined based on the characteristics of the extreme load. This study presents a simulation process to determine the evaluation vehicle loads for bridge safety assessment based on the expected extreme load effects. The simulation results show that the extreme load effects tend to increase along with either increasing traffic volume or proportion of heavy vehicle.