纯压圆弧形钢管桁架拱平面内稳定性能及设计方法  

In-plane buckling and design of two-hinged steel tube circular truss-arches under pure compression

作　　者：郭彦林[1] 郭宇飞[1] 窦超[1] 

机构地区：[1]清华大学土木工程系,北京100084

出　　处：《建筑结构学报》2010年第8期45-53,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(50478013)

摘　　要：目前针对钢管桁架拱平面内稳定性能及承载力的研究较少,缺少相应的设计方法。提出了钢管桁架拱截面剪切刚度表达式,考虑剪切变形的影响推导了纯压两铰圆弧桁架拱屈曲荷载的简化计算公式以及换算长细比表达式。基于有限元方法,全面分析了截面高宽比、矢跨比、腹杆夹角及腹杆截面尺寸等不同参数对平面桁架拱和空间桁架拱弹性屈曲性能的影响,结果表明采用简化公式与有限元分析结果吻合良好。借鉴实腹拱和格构柱的稳定设计方法,采用大挠度弹塑性有限元法系统研究了平面及空间纯压桁架拱的相关稳定承载力,发现节间弦杆长细比与桁架拱整体长细比的比值是衡量局部稳定对整体稳定影响的关键参数,在此基础上提炼出纯压桁架拱的相关作用影响系数,并拟合得到了纯压桁架拱的稳定设计曲线,从而为一般荷载作用下压弯桁架拱的稳定承载力的设计奠定了基础。Until recently, the corresponding stability design method is absent for the lack of researches on the in-plane stability and load-carrying capacity of steel tube truss-arches. In this paper, firstly the expression of sectional shear stiffness is proposed, and the buckling loads and modified slenderness ratio of two-hinged circular arches under pure compression are derived, considering the effects of sectional shear deformation on buckling behavior. Secondly, by adopting finite element numerical method, the buckling analysis of a pure compressive arch is carried out to investigate the influence of different parameters on the elastic buckling behavior of planar and spatial truss-arches, such as sectional height-to-width ratio, rise-to-span ratio, web-member included angle and sectional dimension. It indicates that the buckling loads calculated by the formula derived above are in good agreement with numerical results. Finally, referring to the stability design method of solid webs arch and latticed columns in current Chinese code for steel structures, by elasto-plastic finite element method the interactive ultimate load-carrying capacity of pure compressive truss-arch is studied, considering the influence of member local buckling on global stability. It is found that the ratio between slenderness ratio of intersegmental chord members and that of the whole truss arch is the key factor reflecting that influence. Based on that, the so-called interactive influence coefficient is extracted, as well as stability design curves are proposed for two-hinged pure compression steel tube circular truss-arches.

关 键 词：钢管桁架拱 弹性屈曲 剪切变形 换算长细比 相关稳定 设计曲线 

分 类 号：TU393.302[建筑科学—结构工程]