摘要
针对现有漂浮体系和塔梁铰接体系斜拉桥纵向1阶自振周期简化计算中均忽略双向振动耦合效应影响的状况,采用Rayleigh能量法对这2种体系斜拉桥的纵向1阶自振周期简化计算公式进行了推导。首先,以斜拉桥在地震作用下纵向水平惯性力的传递路径为依据,分别建立了漂浮体系和塔梁铰接体系斜拉桥的简化计算模型;其次,考虑斜拉桥纵向1阶振型呈现出纵向振动与竖向振动相互耦合的特点,基于假定的漂浮体系、塔梁铰接体系斜拉桥主梁和主塔的纵向、竖向位移振动方程,分别对2种体系斜拉桥斜拉索、主塔、主梁的变形能及动能进行了分析和计算;最后,根据能量守恒原理推导了漂浮体系斜拉桥和塔梁铰接体系斜拉桥的纵向1阶自振周期简化计算公式。选取5座已建斜拉桥利用有限元软件进行1阶纵向模态分析,将理论推导结果与有限元计算值进行了对比。结果表明:所提出的简化公式的计算结果与有限元计算值吻合良好,相对误差均小于15%,简化计算方法具有良好的稳定性,可用于斜拉桥纵向1阶自振周期的估算;将漂浮体系斜拉桥纵向1阶自振周期简化计算公式与塔梁铰接体系斜拉桥纵向1阶自振周期简化计算公式配合使用,可为斜拉桥初步设计和方案比选提供参考。
In the simplified calculation of first-order longitudinal natural vibration period of cablestayed bridges with the floating and tower-girder hinge system,the influence of bidirectional vibration coupling effect was neglected.Taking the situation into consideration,simplified formulas for calculating the first-order longitudinal natural vibration period of two kinds of cablestayed bridges were derived by the Rayleigh energy method.Firstly,simplified calculation models of cable-stayed bridges with the floating and tower-girder hinge system were established respectively,on the basis of the transmission path of longitudinal inertial force under the action of earthquake.Secondly,in the light of assumed longitudinal and vertical displacement vibration equations of main girder and tower of cable-stayed bridges with floating and tower-girder hingesystem,the deformation energy and kinetic energy of cables,main girder and tower of two kinds of cable-stayed bridges were analyzed and calculated respectively,considering the intercoupling between the longitudinal and the vertical modes.Finally,simplified formulas of first-order longitudinal natural vibration period for cable-stayed bridges with the floating and tower-girder hinge system were derived by energy conservation principle.The first-order longitudinal modal of five built-up bridges were analyzed by dint of the finite element software.Then theoretical results were compared with values calculated by the finite element method.The results show that results calculated by simplified formulas are in good agreement with values calculated by the finite element method.And the relative errors are less than 15%.The simplified calculation method with good stability can be used to estimate the first-order longitudinal natural vibration period.It provides a reference for preliminary design and scheme comparison of cable-stayed bridges by combing the simplified formulas for calculating the first-order longitudinal natural vibration period of cable-stayed bridges with floating system with ones with tower-girder hinge system.
作者
张文学
寇文琦
陈盈
杜修力
ZHANG Wen-xue KOU Wen-qi CHEN Ying DU Xiu-li(School of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2017年第7期50-57,共8页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51378034
E080505)
北京市自然科学基金项目(8122007)
关键词
桥梁工程
纵向1阶自振周期
能量原理
漂浮体系
塔梁铰接体系
bridge engineering
first-order longitudinal natural vibration period
energy principle
floating system
tower-girder hinge system
