基于分布式长标距应变响应的混凝土梁桥使用性能与安全性能指标反演

项目名称： 基于分布式长标距应变响应的混凝土梁桥使用性能与安全性能指标反演

项目编号： No.51508269

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑科学

项目作者： 洪万

作者单位： 南京工业大学

项目金额： 20万元

中文摘要： 针对混凝土梁桥存在“下挠”及“开裂损伤”问题，本项目拟采用长标距应变传感技术反演混凝土梁桥的使用性能和安全性能的主要指标（挠度及损伤），本项目首先提出一种考虑结构非线性影响的适用于桥梁受力全过程的分布式长标距应变反推结构挠度分布的方法，该方法既适用于结构的弹性阶段，也适用于结构的非线性阶段，同时,该方法适用于动静态荷载的情形。其次，提出一种利用车辆移动荷载下的长标距应变时程面积的比值向量对结构进行损伤识别的方法，该损伤识别指标只和结构的局部刚度相关，与车辆荷载轴数、轴重、速度无关，不仅可以进行损伤定位，也可以进行损伤定量。最后，提出一种利用车辆移动荷载下的长标距应变时程面积的比值向量构造目标函数，进行梁桥的有限元模型修正的方法，修正变量仅包含单个截面的局部刚度及边界条件等有限几个未知变量，未知量大大减少，有利于提高精确度和收敛性，修正后的模型反映了结构的损伤分布信息。

中文关键词： 混凝土梁桥；分布式长标距应变；挠度分布；损伤识别；有限元模型修正

英文摘要： This project aims at developing a method for estimation of service and safety performance index of concrete girder bridge based on distributed long-gauge strain response considering existence of down warping and crack damage in this kind of bridges. Firstly, a method of calculating structural deflection distribution based on distributed strain is presented, and this method is suitable for linear and nonlinear stages of structures. Meanwhile, it can be applied to both static load and dynamic load. Secondly, a method of damage identification of bridges under moving vehicular load based on the ratio vector of area of long-gauge strain time history is presented. The damage index is only in relation to the local stiffness of the structure, and independent of axle numbers, axle weight and velocity of vehicles. This method is suitable for damage localization and damage quantification of structures. Finally, finite element model updating of bridges based on the objective function that comprises ratio vector of area of long-gauge strain time history is also presented. The design variables include local stiffness of single section and boundary condition, and the decrease of design variable enables the improvement of accuracy and convergence. Actual damage distribution of bridges can be well reflected in the updated model.

英文关键词： Concrete girder bridge;distributed long-gauge strain;deflection distribution;damage identification;finite element model updating