摘要
以宁波象山港大桥为背景,研究阻尼器和弹性索组合使用对大跨斜拉桥地震反应的影响。建立了与一般冲刷、局部冲刷两种冲刷类型对应的主桥动力分析有限元模型,对多遇地震和罕遇地震下不同主梁纵向约束方式的主桥模型分别进行了非线性时程分析。通过对分析结果的比较发现:用阻尼器耗能的约束方式对于减小地震下斜拉桥的内力和位移响应都非常有效,减震效果优于单独采用弹性索的约束方式;阻尼器和弹性索组合使用与只采用阻尼器的约束方式相比,构件内力增大幅度很小,却可以更好地控制主梁的梁端位移。因此,在宁波象山港大桥主桥抗震设计中建议采用阻尼器和弹性索组合使用的减震方案。
This paper takes Ningbo Xiangshan Harbor Bridge as an example to study the seismic performance of long-span cable-stayed bridges with both dampers and elastic cable being used as longitudinal restraints of the main girder. The FEM dynamic analysis models were built for two different scouring depths, the nonlinear time history analysis was conducted for the FEM models with different longitudinal restraint conditions under common and rare earthquake. The seismic analysis results demonstrated that earthquake-induced inertial force and deformation response in key positions of the bridge can be reduced dramatically by using only dampers in the main girder, and the dampers are also more efficient than elastic cable in reducing earthquake-induced structural responses. Compared with the restraint condition of simply using dampers, using both dampers and elastic cable in the main girder can limit the deck displacement farther with negligible increase of inertial force response in key positions of the bridge. Therefore, both dampers and elastic cable are recommended as the longitudinal restraints of the main girder in the seismic design of Ningbo Xiangshan Harbor cable-stayed bridge.
出处
《结构工程师》
2008年第5期71-76,共6页
Structural Engineers
基金
国家科技支撑计划项目(2006BAG04B01)
国家自然科学基金项目(50778131)
关键词
斜拉桥
抗震设计
弹性索
阻尼器
cable-stayed bridge, seismic design, elastic link device, damper
