无铺装钢箱梁顶推施工温度效应影响分析

Analysis of the Influence of Temperature Effect of Unpaved Steel Box Girders in Bridge Incremental Launching Construction

随着我国桥梁建设事业日益发展,钢结构被大量运用于大跨径桥梁建设中。对钢结构桥梁而言,温度荷载对结构产生的影响不可忽视。长期暴露在自然环境下的桥梁结构在温度荷载作用下会产生温度变形,从而引起温度应力,对结构安全性和稳定性造成影响,尤其正处于施工阶段的无铺装钢箱梁,温度效应影响更为显著。以临猗黄河大桥为工程背景进行实桥温度场试验,选取典型日实测温度数据进行分析,探讨钢箱梁温度变化规律和分布特征;拟合最不利温度梯度分布函数,并采用有限元软件研究温度作用对钢箱梁顶推施工过程最大悬臂状态下主梁受力影响。结果表明:温度梯度作用下,导梁前端产生较大的竖向位移和横向位移;温度梯度作用对主梁内力影响显著;系统温度作用下主梁纵向变形较大,需设置一定的支座预偏量。

With the increasing development of bridge construction in China,steel structure is widely used in constructing long-span bridges.In the design and construction process of the steel box girder,the influence of temperature load on the structure has been focused on.The temperature load effect will cause temperature deformation of the bridge structure exposed to the natural environment for a long time,which will cause temperature stress and affect its structural safety and stability.Especially for unpaved steel box girders under construction,the impact of temperature effect is more significant.In this paper,the temperature field test of the real bridge is carried out with the Linyi Yellow River Bridge as the background project.The measured temperature data of the typical date are selected for analysis.The steel box girder’s temperature variation law and distribution characteristics are discussed,and the most unfavorable temperature gradient distribution function is fitted.Combined with finite element software,the paper analyzes the influence of temperature on the stress of the main beam during the maximum cantilever state of the steel box girder launching construction process.The results show that under the action of temperature gradient,the front end of the guide beam undergoes significant vertical and lateral displacementꎻthe temperature gradient has a significant impact on the internal force of the main beamꎻunder the overall temperature effect,the longitudinal deformation of the main beam is relatively large,and a certain amount of support pre deviation needs to be set.