Study on the dynamic response of offshore bridge under earthquake action and tsunami impact

Abstract

This paper takes an offshore continuous rigid bridge as the background bridge to reveal the dynamic response law of an offshore bridge under the action of earthquake and tsunami. A tsunami wave is simulated by a dam-break wave. A numerical model of a dam-break impact of a bridge pier is established in Fluent software, and k−ε turbulence model is chosen to solve the Navier–Stokes equation. Meanwhile, ABAQUS software is used to establish a three-dimensional nonlinear full bridge model. The dam-break wave working condition is proposed according to the Stoker theory. The bridge dynamic response index under a single earthquake action and a continuous earthquake tsunami action is calculated, and the dynamic response rules under the two actions are summarized. The results show that compared with the tsunami action alone, the sequential action of the earthquake and tsunami will cause a greater dynamic response of the bridge structure. With the increase in the height of the incoming tsunami wave, the waveform trend difference of the response index will be more significant. Moreover, the influence coefficient of the dynamic response index of the bridge tends to increase as the probability level of the earthquake occurrence decreases.