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为了探讨地震作用下斜拉桥支座脱空现象及其对结构地震响应的影响,分析支座脱空的影响因素.根据一座独塔斜拉桥建立考虑支座脱空的全桥三维非线性有限元模型,以7条实际地震动作为地震输入,采用非线性时程方法研究地震作用下斜拉桥支座脱空现象及其效应,探讨塔梁间纵向设置黏滞阻尼器和墩梁间竖向设置抗拉装置这2种方式对支座脱空的控制效果.结果表明:在纵向地震作用下,支座脱空后梁端产生了较大的竖向位移,当梁体与支座再次接触时会产生较大碰撞力;支座脱空对结构整体地震响应的影响不大,如墩底弯矩、塔柱弯矩、梁端纵向位移等受支座脱空的影响较小;竖向地震动对支座脱空影响明显,考虑竖向地震动后,在输入地震波地面加速度峰值PGA较小时可能产生支座脱空现象;对于背景工程,仅在塔梁纵向设置黏滞阻尼器不能达到支座脱空的控制目标;在墩梁竖向设置抗拉装置能满足要求,但抗拉装置的弹性刚度和拉力均较大;黏滞阻尼器和抗拉装置联合使用可以优化抗拉装置参数,满足支座脱空控制目标时对应的抗拉装置弹性刚度和拉力均大幅度减小.“,”In order to explore the phenomenon of end span uplift for the cable-stayed bridge and the influence on structural seismic response,and to analyze influence factors of end span uplift,3D nonlinear finite-element model of a single-tower cable-stayed bridge was established,in consideration of the end-span uplift.The model was then excited by seven real earthquake ground motions,and nonlinear time history analysis method was used to investigate end span uplift and its effect during the earthquake.The effectiveness of two measures to control end-span uplift effect were further discussed including implementing viscous damper to longitudinally connect the deck and the tower and introducing tensile devices to the deck and the pier.The results show that under longitudinal earthquake excitation,there are large impact forces of the bearing at the moment of re-contacting the deck with bearing after the end-span uplift and large vertical displacement at deck end.The end span uplift of the bending moment at the bottom of the pier and tower sections and displacement at deck end has a limited influence on the seismic response of whole structure.The vertical ground motions enlarge bearing force so that end-span uplift will be caused at smaller peak ground acceleration (PGA).Besides,viscous damper will fail to satisfy the requirement of controlling end span uplift effect.The tensile device is effective in controlling end span uplift along the vertical direction of the pier,but relatively large stiffness and tension forces of the device are required.By both viscous damper and tensile device,the stiffness and tension force of the tensile device is reduced and end span uplift effect is effectively controlled.