上承式两铰桁架拱桥的拱轴线计算长度研究

拱桥的纵向稳定常常采用拱轴线计算长度系数将主拱换算为相当长度的压杆,通过强度校核的形式来控制稳定,但现行规范3]只给出了裸拱的拱轴线计算长度系数;桁架拱桥的拱上建筑对主拱圈具有明显的约束作用,可以提高稳定性,其拱轴线计算长度系数仍有待于进一步研究。通过对上承式两铰桁架拱桥的稳定性影响因素进行分析比较,并对其拱轴线计算长度系数的数值进行分析,拟合得到了拱轴线计算长度系数的简化公式,对实际工程具有一定的指导意义。

Study on Arch Axis Calculation Length of Deck Two-hinged Truss Arch Bridge

The longitudinal stability of arch bridge is controlled often by the arch axis calculation length coefficient to converse the main arch into the corresponding length of compressed bar in the type of strength checking.However,the current criterion only shows the arch axis calculation length coefficient of the bare arch.The spandrel structure of truss arch bridge plays the obvious restriction role for the main arch ring and can improve the stabilization.Its arch axis calculation length coefficient still needs to be further studied.After analyzing and comparing the influence factors on the stabilization of the deck two-hinged truss arch bridge,and analyzing the numerical value of its arch axis calculation length coefficient,the article gives the simplified formula of arch axis calculation length coefficient,which has a certain instructing meaning for the practical projects.