钢管桁架拱和实腹式拱的平面外稳定性能及设计方法

发布时间：2018-03-14 02:34

本文选题：桁架拱　切入点：带支撑实腹式拱　出处：《清华大学》2014年博士论文　论文类型：学位论文

【摘要】：目前钢管桁架拱和实腹式钢拱已经在大跨度工程中有比较广泛的应用。人们对它们的平面外稳定理论研究甚少，平面外稳定设计方法尚未完全建立。本文全面系统的研究了桁架拱和带支撑实腹式拱的平面外弹性屈曲和弹塑性稳定理论，建立了两者的平面外稳定承载力设计方法。由于钢管桁架拱的格构式截面特性，其平面外稳定性能相比实腹式拱更加复杂。本文首先分析了格构式截面剪切变形对桁架拱平面外变形的影响，在此基础上建立了纯压、纯弯桁架拱的平面外弹性屈曲荷载计算公式；其次采用大挠度弹塑性有限元方法，通过引入桁架拱的纯压正则化长细比和纯弯正则化长细比，，分别建立了纯压和纯弯桁架拱的平面外弹塑性稳定设计方法；研究了杆件的变形对桁架拱平面外相关稳定性能的影响，并通过两个相关系数将该影响体现在稳定承载力设计方程中。依据有限元数值计算结果，提出了常见荷载工况下桁架拱的轴力和弯矩稳定承载力相关方程，可用于矩形截面和倒三角截面桁架拱平面外弹塑性稳定设计。采用能量法研究了带支撑拱的平面外弹性和弹塑性受力特点，参考带支撑柱的稳定理论，得到了带支撑拱的弹性和弹塑性门槛刚度理论解及近似解；建立了拱脚为弹性支承时，钢拱的平面外弹性屈曲荷载计算公式，在此基础上得到了支撑沿拱轴线非均匀分布时，相邻拱段间的相互约束作用和支撑间拱段的平面外稳定性能；研究了不同初始几何缺陷分布模式对带支撑拱平面外稳定承载力的影响，并获得了对应于最低稳定承载力的最不利初始几何缺陷；最终提出了带支撑钢拱的平面外稳定设计理论和支撑布置方法。根据钢拱的平面外失稳变形特点，提出了一套专门用于研究钢拱平面外稳定性能试验的加载装置。进行了9根实腹式截面钢拱的平面外稳定试验，研究了拱脚条件、截面类型、矢跨比、长细比、初始几何缺陷以及加载方式等多个因素对钢拱平面外弹塑性稳定承载力的影响，并采用有限元方法对以上结论进行了验证。为拱形结构平面外稳定承载力设计方法的建立提供了试验依据。
[Abstract]:At present, steel tube truss arch and solid web steel arch have been widely used in long span engineering. The design method of out-of-plane stability has not been completely established. In this paper, the theory of out-of-plane elastic buckling and elastic-plastic stability of truss arch and arch with braced solid web are studied systematically, and the design methods of out-of-plane stability bearing capacity are established. Due to the lattice section characteristics of steel pipe truss arch, the stability of the steel tube truss arch is more complex than that of the real web arch. In this paper, the influence of shear deformation of the lattice section on the deformation of the truss arch outside the plane is analyzed, and the pure pressure is established on the basis of the analysis of the effect of shear deformation on the external deformation of the truss arch. The calculation formula of out-of-plane elastic buckling load of pure curved truss arch is given. Secondly, the large deflection elastic-plastic finite element method is used to introduce the pure compression regularization slenderness ratio and the pure bending regularized slenderness ratio of truss arch. The design methods of elastoplastic stability of pure compression arch and pure bending truss arch are established respectively, and the influence of the deformation of the member on the external correlation stability of truss arch is studied. The influence is reflected in the design equation of stable bearing capacity through two correlation coefficients. Based on the results of finite element numerical calculation, the equations of axial force and bending moment stability bearing capacity of truss arch under common load conditions are proposed. It can be used in the elastoplastic stability design of rectangular section and inverted triangle section truss arch. The external elastic and elastic-plastic stress characteristics of braced arch are studied by energy method. The elastic and elastic-plastic threshold stiffness theoretical solution and approximate solution of braced arch are obtained by referring to the stability theory of braced column. The calculation formula of external elastic buckling load of steel arch is established when the arch foot is elastic support. On this basis, the mutual restraint action between adjacent arch segments and the out-of-plane stability performance of arch segment between supports are obtained when the support is distributed inhomogeneously along the arch axis. The influence of different initial geometric defect distribution modes on the external stability bearing capacity of arch with braced arch is studied, and the most unfavorable initial geometric defect corresponding to the lowest stable bearing capacity is obtained. Finally, the design theory of external stability of steel arch with bracing and the method of bracing arrangement are put forward. According to the characteristics of out-of-plane buckling deformation of steel arch, a set of loading device is put forward to study the out-of-plane stability performance test of steel arch. The out-of-plane stability test of 9 steel arch with solid web section is carried out, and the condition of arch foot is studied. The effects of cross section type, aspect ratio, aspect ratio, initial geometric defect and loading mode on the elastoplastic stability capacity of steel arch outside the plane, The conclusion is verified by finite element method, which provides the experimental basis for the design method of out-of-plane stability bearing capacity of arch structure.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU391;TU311.2

【参考文献】