Compared to the traditional suspension bridges with only two pylons, the anti-sliding issue of the saddle on middle pylon is the key problem for three-pylon suspension bridges, which is not clearly presented in existing researches. The basic mechanical model between the middle pylon saddle and the main cable shows that the unbalanced live load is the most important factor for this issue. Because of the obvious geometric nonlinear effect in suspension bridges, the nonlinear influence of vehicle loads on this issue was analyzed. Then based on live load models in various codes, the safety assessment for anti-sliding performance between the main cable and the middle tower saddle was given. The result indicates that the middle pylon can be safe under live loads of various codes. However, the corresponding anti-sliding safety margins are not identical, since different load standards. So further additional studies for refined assessment results based on the real work station are needed.%中间塔鞍座抗滑安全是三塔悬索桥设计的关键问题之一,其特点与传统两塔悬索桥不同.根据鞍座与主缆间的抗滑力学模型,中间塔两侧的不平衡车辆荷载是导致主缆与鞍座滑移的主要因素.由于三塔悬索桥体系存在明显的几何非线性特性,通过分析明确了对于中间塔抗滑问题,不考虑车辆荷 .载的几何非线性是偏安全的,于是可选用基于叠加原理的线性理论计算车辆荷载效应.基于规范车辆荷载模型的中间塔鞍座抗滑安全评估表明,不同规范标准下的车辆荷载都能保证中间塔鞍座的抗滑安全,但相应的抗滑安全水平存在差异.因此为获取更加精细化的评估结果,有必要在桥梁实际工作状态下开展进一步的研究.
展开▼
