腹板开洞钢拱的平面内稳定极限承载力设计理论及方法

腹板开洞钢拱组合了拱和开洞构件的特性,目前在轻轨列车站篷及航站楼等的钢结构中有广泛应用。本文首先用有限壳单元分析了以工形截面腹板开洞圆弧钢拱为代表的拱的平面内弹性屈曲性能,考察了腹板孔洞的几何参数和拱本身的几何参数对屈曲荷载的影响;按照整体屈曲荷载的等效原则,把腹板开洞拱等效为由两个T形截面和缀板组成的格构式构件,并给出了格构式构件的等效截面尺寸。然后研究了各参数下的腹板开洞钢拱的弹塑性屈曲性能,定量考察了孔洞对稳定极限承载力的削弱作用,提出了腹板开洞钢拱特有的单边塑性铰的破坏机理。利用已经建立的拱的稳定系数与拱的正则化长细比的关系,根据等效构件的换算长细比,提出了受静水压力及其它荷载分布形式的腹板开洞拱的平面内稳定极限承载力设计方法。

Design theory and method for in-plane ultimate strength of arches with web openings

As a new type structural member,the steel arch with web openings combines the features of both arches and members with web openings and has found its wide applications.A finite shell element model is employed to study the buckling behavior and ultimate strength of arches with web openings.Firstly,the elastic buckling of two-hinged I-sectional circular steel arches with web openings subject to hydrostatic load is investigated theoretically.The effect of web openings is analyzed comprehensively.For design convenience,the arches with web openings are simplified as battened members composed of two T-sections.Secondly,elasto-plastic nonlinear buckling of arches with different web opening sizes is studied to review arch failure mechanism and to obtain the ultimate strength.Then,according to the established relationship between the arch's stability coefficient and its normalized slenderness ratio,the formulas for the ultimate strength design of arches with web openings subject to hydrostatic load and other forms of load distribution are proposed based on the equivalent slenderness ratio.