温度变化对人字形桥塔施工的影响分析

摘要

松原市天河大桥北汊主桥为(40+100+266+100+40) m双塔空间索面自锚式悬索桥,桥塔为混凝土结构的人字形塔,内斜角度大.塔柱施工期间昼夜温差大,为研究塔柱施工期间温度的影响,采用有限元软件MIDAS Civil建立桥塔施工的仿真模型,在桥塔施工的12个关键施工工序中,选取其中3个关键工序,分析不同荷载组合下温度荷载对施工过程中塔柱的强度、刚度的影响.结果表明:温度的上升与下降对塔柱变形的影响较小,但对其塔柱应力的影响较大;施工过程忽略温度荷载的作用,会导致塔柱拉应力超出限值而产生裂缝;桥塔施工期间,应考虑温度荷载的影响,加强温度监控,采取一定的温控措施.%The north main bridge of Songyuan Tianhe Bridge is a two-tower self-anchored suspension bridge with spatial cable planes and with span arrangement of (40+100+266+100+40) m.The tower is an inverted Y-shaped concrete structure (like the Chinese character "ren" or people), the two legs of which incline inwardly at a big angle.The tower construction has to experience a period with big day-night temperature differences.To study the temperature effect on the tower legs construction, the MIDAS Civil software was used to establish the simulation model of the tower construction.The bridge tower construction were carried out in 12 stages, among which 3 key stages were chosen to analyze the influence of temperature loads on the strength and stiffness of the tower legs during the construction process, under different load combinations.The results show that the temperature rise and fall has minimal impact on the tower leg deformation, but great impact on the stresses in the tower legs.If the effects of temperature loads were ignored during the construction process, the tensile stresses in the tower legs would exceed the limit values, which could consequently lead to cracking.It is necessary to take into account of temperature loads in the bridge tower construction process, closely monitor temperature variation and make proper temperature control prevention.