倒三角截面空间桁架拱平面外弹塑性稳定设计方法研究

OUT-OF-PLANE STRENGTH AND DESIGN OF SPACE TRUSS ARCHES WITH TRIANGULAR SECTIONS

该文研究了倒三角截面两铰桁架拱和固支桁架拱的平面外稳定性能:首先介绍了倒三角形桁架拱的平面外弹性屈曲荷载,此后采用大挠度弹塑性有限元方法,通过引入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。在此基础上,研究了杆件的变形对桁架拱平面外整体稳定性能的影响,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。进一步,依据有限元数值计算结果,提出了全跨水平均布荷载或半跨水平均布荷载作用下桁架拱的轴力和弯矩稳定承载力设计方程,供倒三角截面桁架拱平面外稳定性设计。

This paper is concerned with the out-of-plane inelastic stability of space truss arches with triangular sections. First, the out-of-plane elastic buckling load is derived. After that, the nonlinear inelsatic behaviors of space truss arches under uniform compression and uniform bending, respectively, are investigated, and the design equations are obtained using the normalized slenderness. Effects of component deformation on the out-of-plane strength of space truss arches are subsequently studied and accounted for in the design equations with two additional parameters. Space truss arches subjected to full-span uniformly distributed loads or half-span uniformly distributed loads are studied. Based on FEM numerical results, interaction equations for the out-of-plane strength of space truss arches considering the combination of compression and bending are proposed. These interaction equations can be used for the out-of-plane strength design of space trusses with triangular sections.