Fatigue life estimation of existing bridges under vehicle and non-stationary hurricane wind

During hurricane events, additional damages to existing bridge details might be accumulated from the large stress cycles generated by the non-stationary wind and dynamic vehicle loads. The environmental corrosion could also reduce the structural fatigue strength. Based on the non-stationary wind field modeling techniques and the vehicle–bridge–wind dynamic analysis framework, this paper initiates a fatigue damage assessment of existing bridges with corrosion under vehicle and non-stationary extreme hurricane wind loads. The non-stationary hurricane wind is simulated as a summation of time-varying mean and fluctuating non-stationary components with a time-varying spectrum. Dynamic stress histories are obtained by solving the vehicle–bridge–wind dynamic system. The rain flow counting method is used to obtain the stress ranges and numbers of stress cycles. The corrosion induced fatigue strength degradation is included in the analysis. Numerical examples of an existing long span bridge under simulated non-stationary hurricane winds and vehicles are presented to demonstrate the effects of the dynamic loads and corrosions on the fatigue life estimation of existing bridges.