钢管混凝土拱桥结构受力及参数设计分析

Structural Force and Parameter Design Analysis of Concrete Filled Steel Tubular Arch Bridges

以某钢管混凝土桥梁工程为例,通过有限元分析了自重作用下拱桥的位移及受力,并对使用阶段拱桥的稳定性进行求解,对最不利荷载组合时影响钢管混凝土拱桥稳定的参数进行了分析.结果表明,自重荷载作用下拱桥最大挠度发生在跨中位置,最大负弯矩出现在两端拱脚处,最大正弯矩出现在跨中位置;在不同荷载组合下,结构稳定安全系数在7.35~12.79,恒载及两排车辆全桥满布(偏心布置)工况为最不利荷载组合;改变钢管壁厚、钢管直径,以及选用不同拱轴线形对提高结构安全稳定系数不明显,而采用双K字撑时,可使结构稳定安全系数相对于K字撑时增大近1/3.

Taking a concrete-filled steel tube bridge project as an example,the displacement and stress of the Arch bridge under the action of self-weight were analyzed by finite element method,the stability of the arch bridge in the use phase was solved,and the parameters affecting the stability of the concrete-filled steel tube arch bridge under the most unfavorable load combination were analyzed.The results show that the maximum deflection of the arch bridge under dead weight load occurs at the mid-span position,the maximum negative bending moment occurs at the arches at both ends,and the maximum positive bending moment occurs at the mid-span position.Under different load combinations,the structural stability safety factor is between 7.35 and 12.79,and the dead load and the full bridge(eccentric arrangement)of two rows of vehicles are the most unfavorable load combinations.It is not obvious to improve the safety and stability coefficient of the structure by changing the wall thickness of the steel tube,the diameter of the steel tube and choosing different arch axis shapes.However,when using double K-braces,the safety coefficient of the structure stability can be increased by nearly 1/3 compared with that when using K-braces.