拱塔斜拉桥预应力索塔锚固区节段应力分析

Stress Analysis of Segments of Prestressed Cable-to-Pylon Anchor Zone of an Arch Pylon Cable-Stayed Bridge

某桥为主跨260 m三塔双索面预应力混凝土拱塔斜拉桥,采用空间有限元法对5种荷载工况下索塔锚固区节段应力进行分析。结果表明:空心矩形索塔内布置双向井字形预应力筋能够有效抵消斜拉索水平分力产生的拉应力;索力及预应力分别作用下,距离基准节段中心分别为1.2 m和1.5 m范围内,应力呈现渐进衰减趋势;设计计算中可通过控制侧墙与倒角交界处、斜拉索出口处以及锚块与塔壁交界等处混凝土应力,来控制整个索塔锚固区的应力分布。

A bridge is a prestressed concrete arch pylon cable-stayed bridge with three pylons and double cable planes and with a main span 260 m.The spatial finite element method is used to analyze the stress in the segments of the cable-to-pylon anchor zone of the bridge subjected to 5 load cases.The results of the analysis indicate that the arrangement of dual #-shape prestressing tendons for the hollow rectangular pylon can effectively counteract the tensile stress caused by the horizontal component of stay cables.Under the respective action of the stay cable force and prestressing and respectively within the range of 1.2 m and 1.5 m from the center of the datum segment,the stress tends to gradually decay.In the design and calculation,the stress distribution along the whole anchor zone can be controlled through the control of concrete stress in the intersection between the side wall and rounded corner,in the outlet of the stay cables and also in the intersection of the anchor block and pylon wall.