A novel tri-semicircle shaped submerged breakwater for mitigating wave loads on coastal bridges part I: Efficacy

Abstract

Extreme waves generated by hurricanes, together with storm surges, have led to severe damage and even failures in many offshore structures. This paper presents a novel submerged breakwater design suitable for protecting coastal bridges and other infrastructure. The proposed breakwater design is composed of three identical semicircular shells and a rectangular base using the same total volume of construction material as traditional trapezoidal breakwaters. This configuration permits modular construction and quick installation. A high-fidelity numerical wave tank is established to investigate the performance of the new breakwater device under different conditions with varying wave height, water depth, bridge submersion depth, and spacing between the device and the bridge. The extreme wave is simulated using a second-order solitary wave. According to the observation of a typical scenario, based on the numerical simulations, where waves pass over the novel breakwater and then impact the bridge, it is argued that the new design demonstrates an increased effectiveness to dissipate wave energy. Through analysis of the horizontal and vertical wave forces impacting the T-girder bridge deck, the wave loads are shown to be consistently reduced under all parametric studies. Moreover, it is found that the new breakwater offers improved protection when contrasted with the traditional trapezoidal geometry. The work conducted in this study sheds light on the design of high performing submerged breakwater for mitigating wave loads on coastal bridges.