三塔自锚式悬索桥主索鞍约束体系研究

Research on main saddle's restriction of self-anchored suspension bridge with three towers

以三塔自锚式悬索桥——福州市螺洲大桥为工程背景,采用有限元法分析不同的主索鞍约束体系对结构受力与变形的影响.主要从主梁与主塔的变形和内力、主缆水平不平衡力及抗滑安全等方面研究其变化规律.结果表明,主索鞍固结方式能有效减小主梁的挠度与弯矩,主索鞍有限位移方式能有效减小主塔水平位移及塔顶两侧主缆的不平衡力,提高主缆的抗滑安全性.对于多塔大跨悬索桥而言,控制结构的变形十分重要.为减小主梁挠度可采用主索鞍固结方式,而主缆不平衡力将随之增大,对主缆抗滑安全及主塔受弯较为不利.采用主索鞍有限位移方式能有效减小这一不利影响,但有限位移式主索鞍装置造价较高,其施工及养护相对复杂.因此,主索鞍约束体系的选择应综合考虑结构受力、耐久性以及经济性等因素.

Based on the self- anchored suspension bridge with three towers Luozhou bridge in Fuzhou, the effects on mechanics and deformation of different kinds of main saddle＇ s restriction schemes are compared by using finite element method. Not only the variation of the deformation and inner force of girder and tower, but also the cable＇ s unbalanced horizontal force are investigated. The results show that main saddle consolidation restriction can reduce the deformation and inner force of girder effectively, and main saddle finite displacement restriction can reduce the horizontal deflection of tower top and the cable＇ s unbalanced force remarkably. As for multi - tower suspension bridges with large span, it＇ s very important to control structure deformation. Main saddle consolidation restric- tion could be adopted to reduce the deformation of girder. Meanwhile cable＇ s unbalanced force is in- creasing, and it has bad effect on cable anti - slide and tower bending. Main saddle finite displace- ment restriction could be adopted to reduce this disadvantage effect. But the device of main saddle fi- nite displacement restriction is expensive, and it＇s difficult to construct and maintain. Therefore, the selection of main saddle＇ s restriction scheme should take structure stress, durability, economic effi- ciency and others into account.