考虑桥墩非线性的深水桥梁抗震性能分析

摘要

To study the seismic fluid-structure interaction of a deep-water bridge, an understanding of the pier non-linearity is not enough.Based on the smeared crack concrete theory , this paper establishes a 3D solid pier column model of deep-water bridges taking into consideration the nonlinearity of the reinforced concrete pier , and the feasi-bility of the mechanical behavior of a reinforced concrete structure under the action of a simulative earthquake was studied.Based on the abovementioned aspects , to simulate the water-surrounding pier , Φ-U potential fluid element is used, and a finite element model of a deep-water bridge considering the fluid-structure interaction effect and the nonlinearity of pier is established.In addition, the influence of hydrodynamic effect on the deep-water bridge con-sidering pier nonlinearity during different earthquake recurrence periods is researched.The results show that after pier nonlinearity is considered , the vibration properties of the structure are different from those of a linearly elastic structure.Such differences make the influence of hydrodynamic effect on the structure be different from the influ -ence of hydrodynamic effect on a linearly elastic structure.When the nonlinearity of the pier is apparent , the influ-ence caused by the water flowing to the bridge structure is large.%针对目前深水桥梁抗震流固耦合研究中对桥墩非线性的影响认识的不足,本文基于弥散裂缝混凝土理论,建立了考虑钢筋混凝土桥墩非线性的三维桥梁墩柱实体模型,研究了弥散裂缝混凝土模型对于模拟地震作用下钢筋混凝土结构力学行为的可行性.在此基础上,采用Φ-U格式的势流体单元模拟桥墩周围水体,建立了考虑桥墩的非线性深水桥梁流固耦合分析模型,研究了不同地震重现期下动水效应对采用非线性桥墩的深水桥梁的影响.研究表明:采用非线性桥墩之后,结构的振动特性将与线弹性结构有所差别,从而导致动水效应对结构的影响不同于动水效应对线弹性结构的影响,桥墩非线性较明显时,动水对桥梁结构的影响较大.