Retrofitting of Floating Bridges With Perforated Outer Cover for Mitigating Wave-Induced Responses

Abstract

An investigation has been carried out based on multi-domain boundary element method to analyze the mitigation of wave-induced hydrodynamic loads on a pair of floating rectangular bridges by retrofitting the structures with external porous plates. The study is based on the assumptions of small amplitude water wave theory in finite water depth with the characteristics of wave-body interactions remain unaltered along the bridge. Wave past porous structure is modelled using Darcy’s law. Various hydrodynamic characteristics are studied by analyzing the wave forces acting on the floating bridges and the retrofitted porous structures for different wave and structural parameters. With the introduction of a retrofit, the horizontal force on the bridge reduces irrespective of wave and structural parameters, whilst vertical force increases under certain conditions. Moreover, when the distance between the bridges is an integer multiple of half of the wavelength of the incident waves, both the bridges experience optima in horizontal and vertical wave forces, with both these forces being 180° out of phase. The present study is expected to be useful in the design of efficient bridge structures which will reduce wave-induced hydrodynamics loads on the structure and thus enhance the service life of floating bridges.