时变温度及剪切徐变对大跨径预应力混凝土梁桥长期变形的影响研究

项目名称： 时变温度及剪切徐变对大跨径预应力混凝土梁桥长期变形的影响研究

项目编号： No.51208056

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 建筑环境与结构工程学科

项目作者： 牛艳伟

作者单位： 长安大学

项目金额： 24万元

中文摘要： 大跨径预应力混凝土梁桥(连续梁桥、连续刚构桥)在我国广泛应用，但近年来不断出现的长期变形过量及开裂问题严重制约了此类桥型的发展。目前有关长期变形过量的成因已有一定研究，但由于计算手段限制以及缺少表征性实验，对于时变温度场和剪切徐变作用下，混凝土梁桥的三维时变受力状态和长期往复变形特性研究缺乏。本课题针对大跨径桥梁空间受力特点，首先研究建立预应力混凝土梁桥"三维温度-徐变-收缩"的有限元计算方法；在此基础上通过多方位角混凝土箱梁温度场分布长期试验，探索箱梁空间温度场分布的时变规律并建立相关模型；同时引入高应力状态下预应力混凝土的剪切徐变试验得到相应材料参数；进而采用混凝土材料非线性和时变非线性耦合计算方法，探讨大跨径混凝土梁桥长期变形往复、下挠过量特性；最终结合桥梁实测数据，较为系统完整地解决大跨径混凝土梁桥长期变形问题。成果适用于同类桥梁及复杂结构的长期性能分析和维护，具有广泛的应用前景。

中文关键词： 大跨径混凝土桥梁；徐变；温度；试验；长期变形

英文摘要： Long-span prestressed concrete (PC) girder bridges (including continuous bridges and continuous rigid frame bridges) are used widely in China for their easy construction and low cost. However, in recent years the excessive long-term deformation and cracks becomes the main problem which limits the development of such bridges. There is exist research about the reason of excessive deformation, but the time-varying temperature distribution and shear creep effect to the three dimensional (3D) stress and long-term cycle deformation is rarely involved because of limitation of computation method and lack of representational experiment. According to the mechanical characteristics of long-span bridges, first the finite element (FE) method for 3D Temperature-Creep-Shinkage of PC girder bridges is studied; and based on this, by temperature distribution experiment of box girder segments through multi-directional angle, the time-varying feature and models of box girders' temperature are researched and established. As while, shear creep experiments in high stress PC are carried out and provide the shear creep parameters. Both of the experiments support the anlysis FE method considering concrete material nonlinear and time-effect nonlinear which used next to investigate the mechanism and solution method of long-term excessive c

英文关键词： long-span concrete bridge；creep；temperature；experiment；long-term deformation