千米级斜拉桥船撞动力响应分析实用方法研究

Practical Procedure for Dynamic Response Analysis of Thousand-meter Scale Cable-Stayed Bridge Subjected to Ship Collision

结合千米斜拉桥基础刚度较大的特点,指出采用实用的两阶段方法来计算千米级斜拉桥在船舶撞击作用下的全桥动力响应.该方法采用非线性显式有限元接触分析来进行船桥局部碰撞分析,得到船舶在碰撞过程的特性曲线,并将其作为第二阶段全桥动力响应分析的基础.然后,用动力分析中常用的空间梁单元模型进行全桥动力响应分析,明确船撞下千米级斜拉桥的动力需求或性能.选择主跨跨径为1 500m的千米级斜拉桥为算例,LS-DYNA完成第一阶段的局部碰撞特性的分析,Sap2000开展第二阶段的全桥动力响应分析,其过程表明该方法的基本思路简单实用且有效,能为实际的设计提供指导和依据.

According to the characteristic of large foundation stiffness of thousand-meter scale cablestayed bridge,apractical two-stage procedure is presented to analyze the dynamic response of shipbridge collision.General-purpose contact-impact nonlinear finite-element codes are employed to analyze the local impact responses of ship-bridge collisions firstly.Thus,the impact curve（such as impact force history）can be obtained in the first stage,which will be used in the second stage as an impact excitation.Then,a spatial beam element model is adopted to evaluate the dynamic responses,demand and performance of the whole bridge subjected to vessel impact.A cable-stayed bridge with main span 1500mis taken as a practical case to evaluate the above procedure.In the case,LS_DYNA soft-ware is employed to conduct the analysis of the first stage ship collision with bridge and SAP 2000 software is used to accomplish the analysis of the second stage full-bridge dynamic response.The results shows that the above approach is simple and effective,and may be used to guide the design for thousand-meter scale cable-stayed bridge.