倒三角形截面板管连接式钢圆弧拱在平面内的稳定承载力研究

采用理论推导与数值模拟相结合的方法,对倒三角形截面板管连接式钢圆弧拱在平面内的弹性屈曲和弹塑性屈曲进行了深入研究。首先,理论推导了拱的截面剪切刚度,并提出了拱在全跨均布径向荷载作用下的弹性屈曲公式。此外,还提出了避免连接板和弦杆在拱发生整体弹性失稳之前发生局部失稳的限制条件。然后,分别研究了在全跨均布径向荷载和全跨均布竖向荷载作用下,拱的整体弹塑性失稳机理。结果表明,在全跨均布径向荷载下,拱在1/4跨和3/4跨附近的弦杆会发生屈服,最终发生拱的整体弹塑性失稳。基于数值结果,建立了拱在全跨均布径向荷载作用下的稳定曲线,并针对拱发生整体弹塑性屈曲提出了相应的稳定承载力设计公式。在全跨均布竖向荷载作用下,钢拱发生整体失稳时,在拱脚两端附近的下弦杆会进入屈服。同样地,本文也提出了拱在全跨均布竖向荷载作用下,发生整体弹塑性失稳时的稳定极限承载力设计公式。本文所建议的公式与有限元结果符合得较好,可供实际工程设计参考。

Study on in-plane stability load-carrying capacity of plate-tube-connected circular steel arches with inverted triangle section

This paper mainly investigates the in-plane elastic buckling and elastoplastic buckling of plate-tubeconnected circular steel arches with inverted triangle section by adopting methods of theoretical derivation and numerical simulation. Firstly, the section shear stiffness of the arch is derived theoretically, and the in-plane global elastic buckling load formula of the arch is proposed. Furthermore, the restrictive conditions of preventing chord and connecting plate from local buckling are given. Then, the global elastoplastic instability mechanism of the arch is studied when arches subjected to full-span uniform radial load(FSURL) and full-span uniform vertical load(FSUVL), respectively. The results show that chord yields at 1/4 L and 3/4 L span, and the arch presents global elastoplastic instability under FSURL. Based on numerical results, the stability curve of the arch is built and the corresponding stability load-carrying capacity design interaction equation is suggested. Under FSUVL, the arch will suffer from global elastoplastic instability, and the chord nearby the both ends of arches will yield, too. Similarly, the global stability bearing capacity design interaction equation is also proposed when arches subjected to FSUVL. All the formulas proposed in this paper agree well with numerical results, which provide references for practical engineering design.