跨铁路同步转体桥施工阶段梁体应力及变形监测研究

Monitoring and Study on Stress and Deformation of the Beams in the Construction of Synchronizing Swivel Bridge Across Railway

施工监测是确保桥梁在整个施工过程中安全、稳定的有效手段。结合密涿高速公路跨京哈铁路分离式立交主桥同步转体工程背景,对梁体在整个施工过程中的应力及线形变化进行了监测分析,重点讨论了混凝土浇筑、预应力张拉、拆除支架、转体前后4个阶段的梁体应力及变形特点。据现场实测数据分析可知在施工中,预应力张拉阶段梁端的应力变化最为剧烈,梁端沉降增幅最大;受力最不利的位置在于根部截面。在工程中应重点关注预应力张拉阶段和转体桥的根部截面位置。

Construction monitoring is an effective means to ensure the safety and stability of the bridge in the whole construction process. Taking the separate overpass synchronous rotation engineering of Miyun-Zhuozhou Expressway across the Beijing-Harbin Railway as a background,this paper carried out an analysis and monitoring on the stress and deformation of the beams in the whole construction,and focused on the stress and deformation characteristics of the beams in four stages of concrete pouring,prestressed tension,stent removal and swivel construction. Based on the field measured data,the analysis showed that in the construction,the stress change at the end of beam was the most intense and its settlement amplitude was the largest at the stage of prestress tensioning,while the most unfavorable position of the force was in the root section.We should focus on the prestress tensioning phase and the root section position of the swing bridge.