悬索桥上、下对合型索夹结构分析研究

摘要

To study the mechanical properties of the cable band structure of upper and lower halves type for suspension bridge,the Shuangyong Bridge in Liuzhou was cited as an example.The upper limit value of transverse elastic modulus of the ideally arrayed main cable sustaining macroscopic sense force was derived and with reference to the empirical formulae,the value range of the transverse elastic modulus of the main cable was determined.The finite element model for the main cable and cable band was established,the bolt additional force coefficients and the inner pressure coefficients and disengaging angles of the cable band under changing of the transverse elastic modulus in a certain range were analyzed.The results of the analysis show that the suspender force is the direct cause leading to the obvious non-uniformity of the inner pressure stress distribution in the upper and lower halves of the cable band.The increase of the gripping forces of the bolts can increase the inner pressure stress of the cable band.The bolt additional force produced by the suspender force is not sensitive to the changing of the transverse elastic modulus and the inner pressure coefficients of the cable band will accordingly become less under the forces of the suspenders and main cable.For the bolt additional forces,the influences of the relative stiffness of the bolts and members to be connected should be considered and for the cables band at midspan,the gripping forces of the bolts should be timely adjusted from the control of the disengaging angles.%为研究悬索桥上、下对合型索夹结构的受力特性,以柳州双拥大桥为背景,推导了理想排列的主缆在宏观受力意义下的横向弹性模量的上限值,并结合经验公式确定主缆横向弹性模量的取值范围.建立该桥主缆和索夹有限元模型,分析主缆横向弹性模量在一定范围内变化时的螺杆附加力系数、索夹内压系数和脱空角.结果表明,吊索力是造成上、下索夹内压应力分布明显不均匀的直接原因,增大螺杆夹紧力能增大索夹内压应力;吊索产生的螺杆附加力对主缆横向弹性模量变化不敏感;索夹内压系数在吊索力和主缆力作用下会相应变小;螺杆附加力应该考虑螺栓和被连接件的相对刚度影响;跨中索夹应从控制脱空角入手适时调整螺杆夹紧力.