Numerical Analysis of Wave-Current Loads on Large Steel Caisson in Complex Marine Environments During Sinking Process

This study investigates the wave-current loads on the large steel caisson in complex marine environments during the sinking process. The Xihoumen Rail-cum-Road Bridge was applied as a case. Numerical analysis was condueted to analyze the responses of the steel caisson to wave-current loads with a fluid-solid coupling model. The dynamic responses of the caisson at different sinking depths at different current velocities under pure current forces(wave height = 0) and under combined wave and current forces (with wave heights of 3, 4, and 5 m), respectively, were compared. The results demonstrate that the horizontal forces on the steel caisson are prone to the current velocities, at the same sinking depth, the peak horizontal forces were increased by a maximum 575. 27% when the current velocity was increased from 1 m/s to 4 m/s. The horizontal forces on the steel caisson are substantially increased under the wave-current loads rather than under the pure current loads, while the Overall vertical forces on the steel caisson showed minor changes under the wave-current loads. The influences of the wave-current loads and sinking depth of the steel caisson should be considered sufficiently during the positioning and sinking process. As the sinking depth increases, the Stresses in the caisson strueture correspondingly scale up, with the maximum Stresses increased by 116. 88%. The connections of ropes and caisson should be given great concerns since these are sensitive locations to stress concentration. © 2025 Wuhan Bridge Media Co., Ltd., MBEC. All rights reserved.