预应力混凝土连续弯梁桥悬臂法施工的监控技术研究

Research on monitoring technology for prestressed concrete continuous curved girder constructed by cantilever casting method

结合郑西高铁咸阳渭河特大桥工程,总结了施工过程中影响大跨径预应力混凝土连续弯梁桥应力、应变的主要因素,分析了弯桥结构在悬臂法施工阶段的力学性能和线形变化规律,探讨了曲率半径和季节温差对弯桥的作用效果。研究结果表明:随着曲率半径的减小,静定T构悬臂根部截面的扭矩增大,而弯矩和轴力有所减小,横向位移增加明显;季节温差会引起静定T构端部截面产生较大的横向位移;日照温差应按二维温度梯度模式进行温度作用效应计算,不同的温度梯度模式引起的效应差别很大。

Combined with the Xianyang Weihe Bridge project in Zhengzhou-Xi＇an high speed railway,the main factors of stress and strain of the long-span prestressed concrete continuous curved girder bridge during the construction process were summarized. The mechanical properties and linear variation of curved bridge structure during cantilever construction were analyzed. The effects of the radius of curvature and the seasonal temperature difference were discussed. The results show that with the decreasing radius of curvature,cantilever root section torque of statically determinate T structure is increasing,while the axial force and bending moment are reduced,lateral displacement increases obviously. The seasonal temperature difference will cause a larger lateral displacement of the end cross section of statically determinate T structure. For there is a large difference effects caused by temperature gradient mode,sunshine temperature difference should be calculated according to the two-dimensional temperature gradient mode for temperature effect.