基于现场测试的斜拉桥有限元模型修正

由于多年使用，桥的结构材料等都已经发生变化，因此在研究桥的当前工作状态时，必须依照现场测试结果，将初始模型修正为符合现阶段实际情况的有限元模型。本文以黄河胜利大桥为工程背景，根据设计资料建立了该桥初始有限元模型，用ANSYS通用软件开发了索力修正程序，该程序通过调整拉索的初始应变和附加质量块，使模型索力与设计索力之间误差在5％以内。计算发现，有限元模型中的施工顺序对成桥状态有着很大影响，应通过单元生死技术进行施工模拟。本文以各级加载工况下挠度、索力的变化情况作为控制目标，最终建立了能够反映加载工况下挠度变化、索力变化的黄河胜利大桥基准有限元模型，为今后监测桥的索力变化情况进而了解整座桥的工作状态奠定了基础。

Finite Element Model Updating for Cable-Stayed Bridge Based on Field Testing

Due to many years of use, the structure, material and so on of the bridge have changed. In addition, the detection technology is not very well, so it is not suitable to set up the cable-stayed bridge model which can reflect the bridge＇s real action. It is necessary to amend the finite element model in order to comply with the results of the tests so as to fit the facts now. In this paper, a initial finite element model is built through the design information of the Yellow River Bridge which is the background of the project. A program which could amend the cable force is devoloped using ANSYS common software redevelopment. The program adjusts the initial strain and the mass element, so as to control the error between the calculated cable stress and the design stress less than 5%. In the process, it is found that the construction order in the modeling process has a important effect on the state of the accomplished bridge. The construction order should be simulated by the kill/birth element technology. In this paper the change of the deflection and cable force under several cases is aimed at, so as to set up the benchmark finite element model which could reflect the deflection and cable force changing. This model may establish the groundwork for monitoring the change of the cable force and the working status of the whole bridge.