论文部分内容阅读
以面外失稳的主要影响因素作为构造参数,对已建的钢管混凝土桁拱进行统计分析,构建一虚拟拱,然后参照实际桥例,建立了既有典型意义、又符合工程实际的标准拱。以标准拱为对象,进行面外弹性稳定性的参数分析。结果表明:钢管混凝土桁拱面外稳定性随着拱桥宽跨比增加而增大;拱顶横撑形式对面外稳定性影响较小;其他横撑影响较大,其有利作用从大到小依次为X型与米字型、K型和一字型;拱肋间横撑的疏密程度(拱肋的自由长度)影响较大;桁拱的弹性稳定系数随着矢跨比f/L的增大呈现先增大后较小的趋势,在f/L=0.2 0.25时达到峰值;面外长细比越大面外稳定性越差,面外长细比在80~140区间影响较大,在140~220区间影响减弱。最后,对应用特征值求解拱的面外弹性分支计算方法进行了讨论。结果表明:计算时应以拱所受压力最大的荷载工况,且该方法的计算结果不能有效反映几何初始缺陷和横向力对结构真实的面外失稳破坏的影响。
Taking the main influencing factors of out-of-plane instability as the structural parameters, the statistical analysis of the existing steel-pipe concrete truss arch was carried out to construct a virtual arch. Then, with reference to the actual bridge example, a standard arch with both typical and actual conditions was established . With standard arch as the object, parametric analysis of out-of-plane elastic stability was carried out. The results show that the external stability of CFST truss arch increases with the width-span ratio of the arch bridge. The horizontal bracing of the arch has less influence on the stability of the out-of-plane. The other bracing has a greater effect, For the X type and the Meizi type, K type and a font; arch spandrel between the degree of density (the free length of the arch ribs) greater impact; truss arch elastic stability coefficient with the span ratio f / L When the f / L = 0.2 0.25, the out-of-plane stability is worse, and the aspect ratio is more significant in the range of 80-140 140 ~ 220 range of influence weakened. Finally, the calculation method of out-of-plane elastic bifurcation using eigenvalue solving arch is discussed. The results show that the calculation should be based on the maximum pressure load on the arch, and the calculation results of this method can not effectively reflect the effect of geometric initial flaws and lateral forces on the real out-of-plane failure of the structure.