空间索面的自锚式悬索桥主梁稳定简化计算研究

A Study on Simplified Calculation Method for Main Girders Stability of Self-Anchored Suspension Bridges with Spatial Cables

自锚式悬索桥在荷载作用下,主梁端部承受主缆巨大的水平分力作用,为压弯构件,其稳定是个十分重要的问题。根据弹性支承梁屈曲失稳简化计算方法,推导了适用于空间索面的自锚式悬索桥主梁屈曲失稳简化计算公式,并以江东大桥为例,分别用简化计算方法和有限元法分析主梁稳定,在恒载下两种方法得到的失稳安全系数很接近,且简化公式计算偏于安全,验证了公式的可行性。

Under the gravity loading,the main girders of a self-anchored suspension bridge are subjected to a great compression force horizontally introduced by the main cables and the behavior of the girders is like that of beam-columns, so that their instability is a key issue in design of the self-anchored suspension bridge. On the basis of the buckling design principle of a strut with lateral elastic restraints, a simplified calculation method to assess buckling resistance of the main girders of the self-anchored suspension bridge is developed. In design of the Jiangdong Bridge,the buckling safety factor for the main girders of the bridge is assessed by the simplified calculating method and by the FEA method respectively,and in the permanent gravity loading, the buckling safety factors from the two methods are quite close. Practicability of the simplified formulas is verified by comparison with the FEA method,and it appears that the formulas give a lower load so that it is on the safe side.