拉索预应力损失机理及其对在役张弦结构性能的影响

项目名称： 拉索预应力损失机理及其对在役张弦结构性能的影响

项目编号： No.51478310

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 陈志华

作者单位： 天津大学

项目金额： 84万元

中文摘要： 张弦结构体系已广泛应用于体育场馆、会展设施、交通枢纽等重要工程，服役期内拉索松弛和锈蚀会导致明显的预应力损失，影响结构的承载特性和安全性。现有预应力损失的研究主要集中在施工阶段和温度效应上，对拉索松弛和锈蚀导致的预应力损失及其对结构影响的研究较为缺乏。本项目在分析服役期内拉索预应力损失诱致因素的基础上，探索拉索松弛和锈蚀机理，研究拉索绞捻特性对松弛模型的影响机制，建立考虑拉索松弛和锈蚀影响的拉索预应力时变模型；分析现有三点弯曲法等索力测试方法的适用范围以及存在问题，研制拉索弯曲性能试验装置并开展系列试验，建立拉索抗弯刚度计算公式，探索基于抗弯刚度修正的改进频率法；考虑服役期内拉索预应力损失的时变模型以及拉索内力实测结果，研究拉索预应力损失对在役张弦结构承载特性的影响，建立张弦结构索力检测体系判定、补张拉及换索机制。成果可为大跨结构建设和运营提供理论支撑，对张弦结构安全保障具有重要科学意义。

中文关键词： 张弦结构；拉索；松弛；索力测试；性能状态评估

英文摘要： Cable-supported structures have been widely used in various major engineering projects including stadiums and gymnasiums, convention and exhibition centers, and transportation hub stations. However, existing structures would have prestress loss problem that caused by cable relaxation and corrosion, and this will greatly threaten structural bearing capacity and safety. Current studies on prestress loss mainly focus on the effect of construction and temperature, but the influence of cable relaxation and corrosion on existing structures have been rarely involved in relevant studies. Based on the analysis of the factors that induce the prestress loss of the in-service cables, the cable relaxation and the corrosion mechanism will be explored, and the influence of cable twisting characteristics on cable relaxation model will be studied. Also a time-varying model of cable prestress considering the influence of cable relaxation and corrosion will be established in this project. In addition, considering the application scopes and the problems of current cable force measuring methods, a precise formula for calculating flexural rigidity of stubby cables in beam string structures will be established through elaborate numerical simulation and experimental study. Then based on the precisely modified flexural rigidity, the advanced cable force measurement will be explored. Influence of prestress loss on the bearing properties of existing cable-supported structures will be studied based on the time-varying model, with considering the prestress loss and the measured values of cable force. Mechanism of the cable force measurement, tensioning compensation and cable replacement will also be studied. The results of this project demonstrate a long-term significance in providing scientific support for the construction and operation safety of engineering structures.

英文关键词： cable-supported structure;cable;relaxation;cable force measurement;condition assessment