Dynamic analyses of pile-supported bridges including soil-structure interaction under stochastic ice loads

The Gulf of Bohai has a huge area of floating ice in winter each year, and when seawater freezes, significant uncertainties are introduced in the offshore structural design. In this study, a complete bridge analysis model is proposed to investigate the dynamic responses of offshore bridges in the Bohai Sea subjected to stochastic ice loads by floating sea ice. Based on a real stochastic ice load spectrum, a simulation methodology to generate the stochastic ice load process is proposed. The soil resistance is modelled utilising the American Petroleum Institute-based cyclic p-y, t-z, and Q-z springs. A dynamic analysis is conducted in the time domain utilising the finite element method and considering stochastic ice loads. The influences of undrained soil strength and water depth on the dynamic behaviours of the bridge are systematically investigated. The results show that the dynamic responses of bridges in deep water are much larger than those in shallow water, and the soil–structure interaction (SSI) can substantially affect the structural vibrations. The result from the method can also be used to identify the most critical condition for bridge design under ice loads. •A complete bridge analysis model was proposed to investigate the dynamic responses of bridges under ice loads.•Based on a real stochastic ice load spectrum, a simulation methodology of ice load process was proposed..•The dynamic analysis of a bridge is conducted includes soil-pile interaction under ice loads.•The influences of undrained soil strength and water depth on the dynamic responses of a bridge were investigated.•The results can also be used to identify the most critical condition for a bridge design under ice loads.