三跨变截面预应力混凝土连续梁桥的收缩徐变效应  

Shrinkage and creep effect of three-span continuous variable cross-section prestressed concrete bridge

作　　者：卫建军[1] 

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054

出　　处：《西安科技大学学报》2015年第2期192-196,共5页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金青年基金(51204113);国家自然科学基金(51474173)

摘　　要：混凝土的收缩徐变效应是影响预应力混凝土连续梁桥受力的重要因素。混凝土收缩徐变效应研究是进行混凝土桥梁设计的前提。通过对影响混凝土收缩徐变效应的主要因素分析,揭示混凝土收缩徐变对桥梁变形和内力的影响规律。以某三跨变截面预应力混凝土连续箱梁桥为工程依托,采用有限元仿真分析方法,将连续箱梁所处环境的相对湿度、混凝土加载龄期以及运营时间对混凝土收缩徐变效应的影响进行参数分析。研究认为:混凝土收缩和徐变所引起的连续梁的竖向位移及截面弯矩均随环境相对湿度的增大而减小;随着加载龄期的延长,混凝土收缩作用引起的连续梁竖向位移与截面弯矩总体呈增长趋势,而混凝土徐变作用引起的连续梁竖向位移与截面弯矩变化较小;运营时间对混凝土收缩作用引起的梁体竖向位移影响显著,而对截面弯矩无影响,运营时间对混凝土徐变作用引起的梁体竖向位移与截面弯矩均影响较大。文中研究结果对同类工程设计提供一定的参考价值。The shrinkage and creep effect of concrete is an important factor impacting the mechanical of prestressed concrete continuous beam bridges. Research on effects of shrinkage and creep of concrete is a prerequisite for concrete bridge design. Influential law of the deformation and internal force of bridge caused by shrinkage and creep of concrete can be revealed through the analysis on the main factors affecting the effects of shrinkage and creep of concrete. Finite element analysis on the main factors that influences the shrinkage and creep effect of concrete is studied by taking a three-span variable cross-section prestressed concrete continuous box girder bridge as the research object,and the main factors include environmental relative humidity,loading age of concrete,operation time etc. The results show that with the increasing environmental relative humidity. Both the vertical displacement and bending moment caused by shrinkage and creep are both decreased gradually. The vertical displacement and bending moment caused by shrinkage are increased with the loading time. Bridge operation time has significant influences on the vertical displacement of the bridge caused by concrete creep,while it has little influences on the bending moment. Both the vertical displacement and bending moment caused by concrete creep are influenced greatly by bridge operation time. The results can provide a certain reference value for the design of similar project.

关 键 词：预应力混凝土连续箱梁 混凝土收缩徐变 有限元分析 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]