独柱塔空间缆索自锚式悬索桥动力特性分析

为研究独柱塔空间缆索自锚式悬索桥的动力特性,以南京江心洲大桥为工程背景,运用有限元软件Midas/civil 2015,分别建立了成桥状态的墩底固结模型和桩-土相互作用模型,对比分析了桩-土相互作用对结构动力特性的影响,并分析了恒载集度、加劲梁刚度、桥塔刚度、主缆刚度以及吊杆刚度对该类桥梁动力特性的影响规律。分析结果表明,考虑桩-土相互作用时,结构自振周期延长了1.4s,并且振型发生了变化;恒载集度主要影响结构竖弯振型;加劲梁竖向刚度对结构竖弯振型影响较大;加劲梁扭转刚度对结构各主要振型影响均不明显;桥塔纵向刚度主要影响结构纵飘振型;桥塔横向刚度对桥塔横弯振型影响较大;主缆抗拉刚度主要影响加劲梁竖弯振型;吊杆抗拉刚度的提高对结构整体刚度的贡献可以忽略。

DYNAMIC CHARACTERISTICS ANALYSIS OF SELF-ANCHORED SUSPENSION BRIDGE WITH SPATIAL CABLE AND SINGLE-COLUMN TOWER

In order to study the dynamic characteristics of self-anchored suspension bridges with spatial cable and single-column tower,the main bridge of Nanjing Jiangxinzhou bridge is cited as an example and two spatial finite element models of the completion state,the consolidation model under the pier and the pile-soil interaction model,was established based on the software Midas/Civi1 2015 and compared the influence of pile-soil interaction on the dynamic characteristics of structure,and analyzed the influence of the dead load intensity,the stiffness of the stiffening girder,the tower,the main cable and the hanger on dynamic characteristics of this kind bridges.The results show that the self-vibration period of the structure is prolonged by 1.4s and the vibration mode changes when considering the interaction between the pile and soil.The dead load intensity mainly influences the vertical bending mode.The influence of the vertical stiffness of the stiffening girder on the vertical bending is great.The influence of the torsional stiffness of the stiffening girder on each vibration mode is very little.The longitudinal stiffness of tower mainly influences the longitudinal fluctuation vibration mode and the influence of the horizontal stiffness of tower on tower horizontal bending is great.The main cable tensile stiffness mainly influences the vertical bending mode of the stiffening girder.The contribution of the enhancement of the hanger tensile stiffness to the whole stiffness of the structure can be neglected.