连续大跨度钢桁梁顶推施工监控技术研究

A Study of the Monitoring Techniques for the Incremental Launching Construction of a Continuous Large-Span Steel Truss Beam

结合黄大铁路黄河特大桥的(120+4×180+120)m连续钢桁梁顶推施工,介绍了钢桁梁顶推过程中的监控技术及措施。利用数值模拟仿真计算,检验钢桁梁各杆件安全性并提出较弱杆件加固措施;综合利用应力应变监控元件及挠度监控措施,监控钢桁梁顶推实际应力应变情况;利用千斤顶精确调整各节点间的相对标高,控制桥梁三维姿态,调整各支点反力,保证钢桁梁的成桥线形。各项措施的综合应用,确保桥梁成桥状态达到最优。

With the incremental launching construction of the （120＋4×180＋120）m continuous steel truss beams of the Yellow River Mega Bridge of the Huang-Da Railway as the background,the monitoring techniques and measures adopted in the course of launching the steel truss beams are introduced in the paper. The numerical simulation calculation is used to test the security of all the members of the steel truss beam in the paper,with the corresponding measures to strengthen the weaker members presented.Upon the basis of comprehensively using the stress-strain-monitoring components and the deflection-monitoring measures,the real stress and strain of the steel truss beam in the course of being launched are monitored.Jacks are used to adjust the relative elevation among all nodes so as to control the 3-dimensional attitude of the bridge and adjust the counter-force of each fulcrum in order to ensure the bridge-forming linearity of the steel truss beam.As all the above-mentioned measures are comprehensively adopted,the optimization of the bridge-forming state is achieved.