【摘要】 为探讨不同纵向约束体系对超高墩多塔混凝土斜拉桥地震响应的影响,以墩高178m的赤石特大桥为研究对象,建立全桥有限元模型并进行非线性时程分析,研究了一致和非一致2种纵向约束方式下约束刚度对结构地震反应的影响,并综合对比了各类典型纵向约束体系下结构的抗震效果,最后根据分析结果确定该新桥型的合理纵向约束体系。研究结果表明:一致纵向约束方式下,约束刚度对结构变形的影响较内力更加突出,设计时应以控制结构变形为主,设置较刚性的纵向约束对改善结构抗震性能更加有利;非一致纵向约束方式下,边塔约束刚度对各塔地震反应的分布有重要影响,合理设置边塔纵向约束刚度对平衡结构的响应分布非常关键;对于超高墩多塔斜拉桥而言,采用全漂浮体系和弹性约束体系,抗震效果均不是十分理想,而采用固结体系和弹性-固结体系,可在不显著增大结构内力的同时大幅降低结构变形,是比较合理的纵向约束体系。更多还原

【Abstract】 To explore the influences of different longitudinal constraint systems on seismic response S of super highpier multi-span concrete cable-stayed bridges,the 178 m height Chishi bridge is taken as an object bridge. The finite element model is built to conduct the nonlinear time-history analysis. The influence of the longitudinal stiffness on the seismic behavior is analyzed,both of the uniform and non-uniform longitudinal restraint systems are considered. Then,the effects of various longitudinal constraint systems are compared to propose the reasonable longitudinal restraint system for this new type cable-stayed bridge. The analysis results indicate that the effect of the longitudinal restraint system on the displacement is more remarkable than internal force under uniform constraints and it’s better to control the deformation for the bridge design; Setting up the reasonable restraint stiffness of edge towers is critical to balance the response distribution of structure under non-uniform longitudinal constraint. The floating system and elastic constraints system should not recommend to be used,while the consolidation system and elastic-consolidation system is suitable to super high-pier multi-span concrete cable-stayed bridges because they can greatly reduce the structure deformation and will not observably increase the internal force at the same time.更多还原