三塔悬索桥主缆与中塔鞍座抗滑简化计算方法

为研究三塔悬索桥主缆与鞍座的抗滑特性,给出了三塔悬索桥主缆抗滑安全系数的简化计算方法.考虑活载作用下塔、缆变形以及加载跨与非加载跨主缆内力的平衡关系,推导鞍座处主缆抗滑安全系数的解析计算公式;建立有限元模型对公式进行验证;研究垂跨比、塔缆刚度比、恒活载比、跨径等主要设计参数对主缆抗滑安全系数的影响.研究表明:该公式可用于悬索桥初步设计阶段主缆抗滑安全系数的估算,能够为设计参数的合理取值提供理论依据.主缆抗滑安全系数随着塔缆刚度比增大而减小,当塔缆刚度比小于3时,增大塔缆刚度比,主缆抗滑安全系数迅速减小,当塔缆刚度比大于3时,塔缆刚度比对主缆抗滑安全系数影响较小;垂跨比对主缆抗滑安全系数的影响取决于桥塔刚度;主缆抗滑安全系数随着恒活载比值及跨径增大而增大.

Simplified calculation method of anti-slip stability between main cable and saddle of three-tower suspension bridges

To study anti-slip characteristics of main cable and saddle of three-tower suspension bridges, a simplified calculation method for calculating anti-slip factor was proposed. Analytical formulas for calculating anti-slip factor were deduced and finite element models were established to verify formulas. The effects of some important design parameters on the anti-slip factor were studied. Analysis shows that the analytical method has a high accuracy, which can be used in preliminary design of three-tower suspension bridges. With the ratio of tower and cable stiffness increasing, the anti-slip factor decreases; when the ratio of tower and cable stiffness is less than 3, changing the ratio of tower and cable stiffness has a great influence on the anti-slip factor. When the ratio of tower and cable stiffness is more than 3, the anti-slip factor is not sensitive to the ratio of tower and cable stiffness. Effect of sag-to-span ratio to the anti-slip factor depends on the tower stiffness. With the increment of span length and the ratio of dead load and live load, the anti-slip factor increases.