一种悬索桥主缆计算的新方法

New Method for Calculating Main Cable of Suspension Bridge

基于对主缆索段的受力分析,在建立各索段统一线形方程的基础上,找到主缆最低点的位置及其斜率,利用变形相容条件建立方程,以主缆张力水平分力的变化规律求解方程,提出一种受力更明确、适应性更强、计算更简便的主缆线形计算方法,并将其总结为斜率爬升法。该方法对平面主缆悬索桥的平面缆索结构均能保证求解收敛,经过算例论证,计算精度较高。在求解主缆水平分力的基础上推导主缆坐标、有应力长度和无应力长度的求解方法。同时研究主塔不等高时,主缆斜率最小点的位置和斜率大小变化情况,并研究不等高主塔对主缆受力和主缆线形的影响,结果表明不等高主塔的主缆斜率最小点会向较矮的主塔一侧偏移,且较小的主塔高差会对主缆受力和主缆线形产生较大影响。

Based on stress analysis of main cable section,as well as the unified linear equation of each cable section,the position and slope of the lowest point of the main cable were found,the equation was established using the deformation compatibility conditions,which was solved by the change law of horizontal component force of the main cable. Finally,a calculation method for the main cable shape with more explicit force,stronger adaptability and simpler calculation was put forward,as the slope climbing method. This method can guarantee the convergence of all suspension bridges,and the calculation accuracy proves to be higher by example. On the basis of solving the horizontal component force of the main cable,the solution method for the main cable coordinates,the length of stress and the length of non-stress was deduced. At the same time,the position of the minimum point of the main cable slope and the change of the slope when the main towers were unequal in height were studied. The influence of the unequally high main towers on the main cable force and the main cable shape was also studied. The results show that when the towers are unequal in height,the point with the minimum slope of the main cable will drift to the lower side of the main tower. The height difference of the shorter main tower will have greater influence on the force and the shape of the main cable.