系杆拱桥的稳定性分析

Analysis on the Stability of a Tied Arch Bridge

刚性梁柔性拱组合式桥梁是常用的下承式或中承式系杆拱桥。为保证拱的空间稳定性,常采用多肋式,即两榀或多榀设横系梁或桁架组合;大跨径有把拱平面倾侧形成提篮式。采用独榀拱布置时会遇到裸拱的空间稳定性问题,考虑到拱梁间吊杆的存在,依托系梁的强大抗弯刚度,为拱提供了抵抗失稳的能力。根据小挠度稳定性理论推导出拱在面外失稳时吊杆产生的扶正力,从而计算拱的临界压力。根据公路桥规相关规定提出可供实用的计算长度,验算拱的正截面抗压承载力,并以实例说明相关的计算。

The flexible arch with rigid beam is a commonly arch bridge structure with through and half through. In order to ensure the spatial stability of the arch, several ribs are usually adopted with transverse girder or truss combination. Some large span arch bridge has the inclined arch plane to form the basket type. The spatial stability of bare arch is encountered when single trusses rib are used. Because the existence of suspenders between arch beams and the strong flexural rigidity of tie beams, it provides the arch with the ability to resist instability. According to the theory of small deflection stability, the supporting force of the suspenders when the arch is unstable outside the surface is deduced to calculate the critical pressure of the arch. According to the relevant specification of the highway bridge, the practical calculating length is proposed, the positive section compressive bearing capacity of the arch is verified, and the relevant calculation is illustrated with an example.