新广州站内凹式索拱结构索夹节点抗滑性能分析

Anti-sliding performance of cable clips of inner concave cable arches in the New Guangzhou Railway Station

新广州站主站房主要采用内凹式索拱结构,由于与撑杆连接处拉索两侧的不平衡索力较大,索夹节点的抗滑性能影响了索拱结构的承载力。利用ABAQUS有限元软件对索夹节点进行非线性抗滑性能分析,并与索夹节点足尺模型的抗滑性能试验实测结果进行比较,分析材料非线性、索与索夹间的接触特性、螺栓预紧力等对索夹节点抗滑性能的影响,进而采用虚拟温度法分析了施拧顺序、索横截面收缩对螺栓预紧力的影响。分析结果表明:有限元计算与试验实测结果吻合良好;新广州站内凹式索拱结构索夹节点具有较好的抗滑性能,在设计荷载作用下,节点安全可靠;索夹节点抗滑性能分析中应考虑材料非线性对索夹的影响;索夹抗滑力随着摩擦系数、螺栓预紧力的增长非线性提高;索的滑移会对索夹孔道和拉索本身产生损伤,使索夹的抗滑力降低;采用从螺栓群中心间隔向外的施拧顺序可有效减弱螺栓之间的相互影响,减小螺栓预紧力的损失。

Inner concave cable arches are mainly used in the roof of main building of the New Guangzhou Railway Station. As the unbalanced forces of a cable are relatively large where the cable connects struts and changes its direction, sliding resistance of the cable clip significantly affects the bearing capacity of the cable arch. Nonlinear anti- sliding analysis of the cable clips was carried out with the aid of ABAQUS, and the FEM results were compared with the experimental data of the full size model of the cable clip. The effects of the material nonlinearity, the contact characteristics between cable and clip, and the pre-tightening forces of high-strength bolts were investigated. Using a pseudo-temperature method for tightening, the effects of prestressing scheme and shrinkage of cross section areas of cables on the pre-tightening loss were discussed. The results show that the FEM results agree well with the experimental data. Cable clips of the inner concave arches used in the New Guangzhou Railway Station have good anti- sliding performance, and they are safe subjected to design loads. The material nonlinearity should be considered in the contact analysis of the cable clips. The anti-sliding stress of a clip is nonlinearly raised by the increase of friction coefficient and pre-tightening force. Further, sliding of cables would damage the channel of the clip and the contact surfaces of the cables, and reduce the anti-sliding performance of the clip. Unavoidable interaction among the bolts can he neatly weakened by adopting optimized scheme of prestressing （ symmetrically and diagonally distributed from the center of bolts to the outside）, to reduce the pre-tightening loss of the bolts.