双缆多跨悬索桥力学性能及主缆用钢量研究

为了进一步明确双缆多跨悬索桥的力学和经济性能，比较了双缆多跨悬索桥与传统多跨悬索桥在活载作用下的加劲梁变形及桥塔受力，分析了二者主缆用钢量的差异；拟定双缆体系与传统体系的四塔三跨悬索桥有限元模型，分别计算了活载作用下的结构变形及受力。研究结果表明:双缆悬索桥体系的主缆纵向刚度可达传统悬索桥体系的2~4倍甚至更高，双缆体系纵向刚度与上缆和下缆的垂度及恒载在上下缆之间的分配比例有关，双缆体系主缆用钢量与传统体系相当；在桥塔抗推刚度相对较低的情况下，双缆多跨悬索桥在活载作用下的加劲梁挠度及塔底弯矩均远小于传统多跨悬索桥体系，采用双缆体系可有效增大多跨悬索桥的结构刚度。

Study on Mechanical Properties and Steel Consumption of Double-cable Multi-span Suspension Bridge

In order to determine the mechanical properties and economic performance of double-cable multi-span suspension bridge, the stiffening girder deformation and bridge tower stress of double-cable multi-span suspension bridge and traditional multi-span suspension bridge under live load were compared, as well as the steel consumption of the two main cable systems was analyzed. Finite element models of the suspension bridge with four towers and three main spans in double-cable system and traditional cable system were established, and the deformation and force of the structure under live load were calculated respectively. The study results show that the longitudinal stiffness of main cable in double-cable system can be two to four times higher than that of the traditional suspension system. The longitudinal stiffness of double-cable system is related to the sag and the dead load distribution of the upper and lower cables. The steel consumption of double cable system is almost the same as the traditional cable system. The deflection of stiffening girder and bending moment at tower bottom in double-cable suspension bridge are much smaller than that of the traditional multi-span suspension bridge when the anti pushing rigidity of bridge tower is relatively low. The double-cable system can increase the stiffness of multi-span suspension bridge effectively.