一种确定既有斜拉桥内力初始状态的方法研究

Study on a Method of Determining Initial State of Internal Force of Existing Cable-stayed Bridge

对运营多年的斜拉桥进行索力调整,也就是内力优化调整,与优化一个处于设计阶段或正在施工过程中的斜拉桥内力优化不同,主要体现在前者施工工序的不确定和材料结构参数的退化。把施工工序的不确定和结构参数的变化以及外荷载的改变引起的相应桥梁结构的位移归于索力的变化,基于静力测试数据的基础上,验证了索力的变化和位移的变化之间存在着对应关系,提出了依据"索力-位移"对应关系的参数识别方法以确定既有斜拉桥的内力初始状态。该法应用于运营多年的G325九江大桥斜拉桥调索换索加固工程中,确定了桥梁的内力初始状态,指导了该桥调索加固工程,检验了实测参数误差对参数识别结果的影响程度。

Cable force adjustment,that is also called the internal force optimization adjustment,has been execu-ted for the cable-stayed bridge after years of operation,which is different from the internal force optimization ad-justment for a cable-stayed bridge in its design stage or under construction stage,mainly because of the uncer-tainty of the former construction procedure and the degradation of the material structure parameters.In this pa-per,the change of cable force arising from the uncertainty of construction process,the variation of structure pa-rameters and corresponding displacement of bridge structure from the external load,on the basis of the static test data,has been verified to have a close relationship with the change of displacement,so the parameters identifica-tion method on the basis of “cable force-displacement”corresponding relation has been put forward to determine the initial state of internal force of the cable-stayed bridge.The method is applied to the reinforcing of G325 Jiu-jiang Bridge with years of operating by cable adjustment and cable replacement,with the initial state of internal force being determined,to guide the whole reinforcing project,which has examined the influence of measured parameters variation with the parameters identification results.