Estimation of Horizontal Wave Pressure on the Caisson Protected by Tetrapods

Physical experiments were performed in a two-dimensional wave flume to measure the horizontal wave pressure acting on a caisson protected by Tetrapods. The experiments were conducted using 20 regular waves with varying wave heights and periods. The coverage ratio of Tetrapods placed in front of the caisson was adjusted under different conditions of caisson height, water depth, and rubble mound height. The results indicate that when Tetrapods do not fully cover up to the crest level of the caisson, the wave pressure on the unprotected section of the caisson increased significantly compared to the pressure on an upright vertical wall without Tetrapods. Since the current design standard do not provide a method for estimating wave pressure on this type of structure, a pressure adjustment factor is proposed based on the concept of the coverage ratio (CR) defined by Lee and Oh (2025). The proposed method can be applied for estimating horizontal wave pressure on the caisson when it is fully or partially covered with Tetrapods.