Experimental Study on Characteristics of Tsunami bore Force on Multi-box girder

The characteristics and influencing factors of the tsunami bore force on the multi-box girder are experimentally studied for the first time by using breaking solitary waves to simulate the tsunami bore. The factors influencing tsunami bore force such as wave height a, water depth h, and clearance Z are investigated. It is found that the tsunami bore force time history curve can be divided into three stages, i.e., the impinging stage, the fluctuation stage, and the quasi-stable stage. The horizontal and vertical tsunami bore force maxima (Fx+ and Fz+, respectively) occur in the impinging stage. The girder model is decomposed into panels and the contribution of each panel of the multi-box girder to the tsunami bore force maxima is significantly different from that of the T-girder because of the difference in the geometric shape of the upstream panel. The contribution of the side panels of the multi-box girder to Fz+ is larger than that of the T-girder, because the horizontal projection area of the side panels of the multi-box girder is larger than that of the T-girder. And Fx+ generally decreases with clearance and increases with wave height. However, Fx+ firstly increases and then remains stable as the wave height increases when the clearance is smaller (for example, less than 0.04 m). When h = 0.64 m and Z = 0.02 m and the wave height increases from 0.12 m to 0.21 m, the increment of Fx+ is 221.76 %, Fz+ increases with wave height but significantly decreases with clearance. When h = 0.61 m and a = 0.15 m, the clearance increases from 0.01 m to 0.07 m, the reduction of Fz+ is 87.56%.