Bridges, Tunnels and other Transportation Structures
Full Session with Abstracts
With coupled dynamic impacts from coastal multi-hazards, such as hurricane induced wind and waves, slender coastal bridges could have complex dynamic responses and stress states in structural details, leading to fatigue damage accumulations. Simulation of the coupled vehicle-bridge-wind-wave (VBWW) system could be very complicated. Different loading scenarios especially associated with stochastic environmental loadings from wind and waves with potential correlations have even larger computational demands. Therefore, there is a significant need in modeling the coupled VBWW system as well as the environmental loading scenarios more effectively. High computational efforts are also needed to establish multi-scale coupled dynamics with sub-modeling techniques to capture the stress variations in the local details that might have short cracks initiated or propagated. In the present study, support vector machines are implemented to quantify the fatigue damage of bridge details based on the established probabilistic fatigue damage assessment framework for coastal slender bridges. Firstly, the marginal probability distribution of the environmental loadings, such as the key parameters for wind and waves are modeled using a copula approach. Multi-scale finite-element analysis (FEA) are performed to provide benchmark results and the equivalent stress ranges are obtained as well as the corresponding number of cycles calculated using the rain-flow counting method. Considering different uncertainty sources of the VBWW system, support vector machines are used to link multiple random input parameters for the environmental loadings and the fatigue damage accumulations. With different training strategies, the fatigue life for critical local details can be obtained considering the life-cycle changes of coastal environmental conditions. Case studies for a coastal slender coastal bridge are provided, and effects from different parameters, such as the traffic volume, vehicle weight, local detail conditions, etc., are discussed, as well.