交叉布索预应力立体桁架拱静力与稳定性研究

摘要

In order to improve the bearing capacity and rigidity of the pure arch structure,a new cable arch structure is proposed based on the concept of the beam string structure.Ordinary arch and cable arch models with span of 100m are built.The maximum deflection,horizontal support reaction,peak value of member internal force and distribution of internal force,ultimate load and buckling mode of the structure,and the influence of the position of cable joints are analyzed with utilizing ANSYS.The result shows that,the adoption of the prestressing system can significantly improve the stress state of the truss arch,along with the rigidity and ultimate bearing ca-pacity of the structure.And the optimal ratio is 0.3 under full-span load and half-span load.The position of the cable joints has great influence on the ultimate bearing capacity of the structure.%为提高拱结构的承载力与刚度，改善其静力性能，根据张弦梁结构的布索特点，提出一种新型索拱结构。选取桁架拱为研究对象，建立跨度为100 m的交叉布索预应力桁架拱结构和普通桁架拱结构模型，采用ANSYS分析不同矢跨比下各布索方案结构的最大竖向位移、支座水平反力、杆件内力峰值和内力分布情况、在全跨和半跨荷载作用下的静力稳定性、屈曲模态，以及拉索节点位置对其稳定性能的影响。研究结果表明：索杆体系的引入能有效改善纯拱的受力性能，提高结构的极限承载力和刚度；在全跨、半跨荷载作用下，本文建议的结构最优矢跨比均为0．3；拉索节点位置对结构极限承载力有很大影响。