先张法预应力U型梁施工关键技术研究

Reserch on key technology of pre-tensioning prestressed U-shape girder

依托深圳市城市轨道交通6号线工程实际,针对大截面U型梁的结构特点,研究设计了U型梁的先张施工工艺,开发了整体压柱式制梁台座,克服了不同跨度梁型长度调整的问题,实现了张拉系统在台座外张拉作业;开发了智能张拉系统,有效控制了单根预应力筋的张拉力值;建立了U型梁数值计算模型,分析其在不同荷载组合下的强度和变形特性,结果表明:U型梁的截面强度、预应力钢绞线最大应力、徐变变形、挠度以及梁端转角等指标均符合规范要求,所设计的U型梁结构安全;梁端产生了拉应力,上翼缘的普通钢筋需加强。本研究可为类似U梁工程提供有益参考。

Based on the engineering project of Shenzhen Metro Line 6,combining the structure characteristics of large cross section U-shape girder,construction process of prestressed U-shape girder was designed.The beam fabrication pedestal was also designed to solve problems caused by span differences,then the tension system can work outside the pedestal.A prestressed intelligent tension system was developed to preciously control the tensioning force of the prestressed tendons.By establishing the three dimensional numerical calculation model,the strength and the deformation characteristics of U-shape girder were analyzed.The results show that the strength,maximum stress,the creep deformation,and the deflection,they all meet the requirements of the code.The U-shape girder is economic and reasonable.The results can provide helpful suggestions for the designand practice of the similar engineerings.