Study on anti-tsunami optimization design of bridge pier: A new type bridge pier

Abstract The surface of the bridge pier is divided into upstream surface and downstream surface. The tsunami force characteristics and generation mechanisms for regular piers, i.e. square, circular and diamond piers, as well as pressure distribution and flow field around piers are discussed. Results show that the upstream surface of the diamond pier is most beneficial to reduce water blocking effect and to lower runup at the stagnation point, which ultimately reduces the tsunami force on the upstream surface before tsunami bore reaches the downstream surface. Downstream surface of the circular pier is most beneficial for two branches of tsunami bore flow back and run up on the downstream surface, which generates larger negative tsunami force on downstream surface larger earlier, and ultimately makes entire tsunami force on circular pier smaller after tsunami bore reaches the downstream surface. Based on which, a new type pier is invented by combining the upstream surface of diamond pier and downstream surface of circular pier together. Further, the mitigation effect of new type pier is validated and the mitigation mechanism is explored. Among circular pier and the three piers of new type, N60 is proven to the best to reduce tsunami force.