摘要
由于桥墩的质量与上部结构的质量相比通常是比较小的 ,各桥墩高度和截面大致相同的连续桥梁可以简化为单自由度体系进行抗震设计。当在桥面大梁与桥墩之间设置隔震橡胶支座时 ,上述规则型桥梁可以看作串连型双自由度体系。文中根据桥墩的水平刚度远大于橡胶支座的水平刚度和上部结构的质量甚大于桥墩的特点推导了此双自由度体系的自振特性 (包括自振周期、振型、地震作用的振型参与系数和振型阻尼比 )的简化计算公式。这些公式可以方便地应用于隔震桥梁的抗震设计。此外 ,文中还分析了这些简化公式的计算精度与双自由度体系质量比和刚度比的关系。精度分析和数字实例的计算结果表明 。
The seismic?isolation regular bridge is regarded as a double degree?of?freedom system of shear model.Based on the peculiarities of that the horizontal stiffness of piers is much greater than that of rubber bearings and the mass of the superstructure is much larger than that of piers, a set of approximate formulas for calculating natural frequencies, mode shapes, modal participation factors,and modal damping ratios are proposed in the paper. These formulas can be easily used in design of seismic?isolation regular bridge. The accuracies of formulas how depending on mass ratio and stiffness ratio are analyzed. The results of accuracy analysis and numerical example show that the proposed simplified formulas are accurate enough.
出处
《土木工程学报》
EI
CSCD
北大核心
2001年第3期53-58,66,共7页
China Civil Engineering Journal
基金
国家自然科学基金资助重大项目(59895401)
关键词
隔震
规则型桥梁
剪切型
自振频率
振型
振型参与系数
振型阻尼比
seismic-isolation
regular bridge
bridge natural frequencies
mode shapes
modal participation factors
modal damping ratios
