基于能量法的斜拉桥纵向1阶自振周期简化计算

发布时间：2018-06-19 23:10

本文选题：桥梁工程 + 纵向阶自振周期　；参考：《中国公路学报》2017年07期

【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。
[Abstract]:In view of the fact that the coupling effect of bidirectional vibration is neglected in the simplified calculation of longitudinal first order natural vibration period of existing floating system and tower girder hinged cable-stayed bridge, The Rayleigh energy method is used to deduce the simplified formulas for calculating the longitudinal first order natural vibration period of these two cable-stayed bridges. Firstly, based on the transmission path of longitudinal horizontal inertial force of cable-stayed bridge under seismic action, the simplified calculation models of floating system and pylon girder hinge system cable-stayed bridge are established respectively. Considering that the longitudinal first order vibration of cable-stayed bridge presents the characteristics of the coupling of longitudinal vibration and vertical vibration, the longitudinal and vertical displacement vibration equations of the main beam and main tower of cable-stayed bridge with hinged tower and floating system are considered. The deformation energy and kinetic energy of two kinds of cable-stayed bridges are analyzed and calculated. Based on the principle of conservation of energy, a simplified formula for calculating the longitudinal first order natural vibration period of cable-stayed bridge with floating system and cable stayed bridge with hinged tower beam is derived. Five existing cable-stayed bridges were selected to carry out the first-order longitudinal modal analysis using finite element software, and the theoretical results were compared with the finite element calculation results. The results show that the calculated results of the simplified formula are in good agreement with the calculated values of the finite element method, and the relative errors are less than 15. The simplified calculation method has good stability and can be used to estimate the longitudinal first order natural vibration period of cable-stayed bridge. The simplified calculation formula of longitudinal first order natural vibration period of cable-stayed bridge with floating system is combined with the simplified formula of longitudinal first order natural vibration period of cable-stayed bridge with tower girder, which can provide a reference for the preliminary design and scheme selection of cable-stayed bridge.
【作者单位】：北京工业大学建筑工程学院;
【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)
【分类号】：U441.3;U448.27

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