斜拉桥的弹性约束减震研究

设置梁塔之间纵向弹性约束是飘浮和半飘浮体系斜拉桥减震的一种常用办法.文中采用时程分析方法,研究了弹性约束刚度对斜拉桥减震的影响,并考虑不同场地土类别、不同斜拉桥结构对弹性约束减震效果的影响.结果表明,采用弹性约束抗震措施可以有效地降低塔梁交接处索塔弯矩和主梁纵向位移,但对塔顶位移和索塔墩底弯矩的减震效果不明显,甚至有增大趋势,场地类别和结构变化对弹性约束减震效果影响较大.因此,在实际工程中采用弹性约束减震时应根据桥梁的实际情况仔细分析方可应用.

Study on Shock Absorption of Elastic Restraint of Cable-stayed Bridge

Elastic restraints between main beam and tower are commonly used to reduce the seismic re- spond of floating or half-floating system cable stayed bridges. In this paper, considering different site classifications and different structures of cable stayed bridge, the effects of elastic restraint stiffness on seismic responds are researched by using time-history analysis. Results show that the elastic re- straint with appropriate stiffness can reduce effectively the moment of tower at height of main beam and longitudinal displacement of main beam. However, the moment of the tower at bottom and the displacement of the top of tower decrease indistinctively, even increase generally. The classifications of site and changes of structure have large effects on shock absorption of the elastic restraints. So the analysis must be done in detail according to the actual conditions when the elastic restraint is used for shock absorption of cable stayed bridge.