Dynamic response of a three-span continuous RC bridge under random waves using an experiment-based method to calculate the slamming force from wave-breaking effect

Abstract

Bridges in coastal regions are vulnerable to breaking waves, which can impose substantial wave loads and trigger severe dynamic responses. This paper represents practical marine conditions using random waves generated from a spectrum-based method and proposes a simplified approach to calculate breaking-wave loads by combining quasistatic and slamming components. The slamming force model is established through experiments and expressed as a normalized exponential rise–decay function, with parameters obtained from regression analysis and probabilistic joint distribution. The framework is verified by experiments and applied to a three-span continuous RC bridge with a 120m length, 20.6m height, and 15.6m water depth. The example case considers a JONSWAP spectrum with a significant wave height of 7.0m and a typical period of 9.38s. Results show that the wave-breaking effect increases the peak wave load on a pier by approximately 3–4 times compared with the non-breaking case, leading to 4–5 times larger pier-top displacements. Bearing deformation exceeds 10 times. These findings highlight strong interaction between piers and bearings and reveal bearings as a critical vulnerability, even when not directly impacted by waves. The developed approach offers an efficient tool for assessing the dynamic response of coastal bridges under extreme wave conditions.