有初始几何缺陷混凝土系杆拱桥极限承载力分析

Ultimate load carrying capacity analysis of concrete tied arch bridges with initial geometric defects

分别采用线弹性分析方法、几何非线性分析方法、材料非线性分析方法及双重非线性(几何非线性和材料非线性)四种不同分析方法对某系杆拱桥进行极限承载力分析.通过比较四种方法的分析结果,研究非线性对于分析结果的影响.采用考虑双重非线性的分析方法对存在初始缺陷的系杆拱桥进行极限承载力分析.结果表明:此类拱桥应以双重非线性分析方法进行极限承载力分析计算;面内初始几何缺陷对极限承载力的影响要比面外初始几何缺陷的影响大;面外初始几何缺陷对于系杆拱桥极限承载力不会产生较大影响;我国规范所给拱肋施工允许偏差可适当放宽,同时对于轴线横向偏位的允许范围应该大于竖向偏位的允许范围.

A concrete tied arch bridge with different initial defects is analyzed in the paper by means of linear,geometric nonlinear, material nonlinear, and dual nonlinear （geometric nonlinear and material nonlinear） methods respectively, and the nonlinear influence on the analysis results of concrete tied arch bridge is studied. The effects of different initial defects on concrete tied arch bridge are also studied by dual nonlinear method. The results show： In order to get accurate results, the influence of geometric nonlinearity and material nonlinearity must be considered when studying the ultimate load carrying capacity of concrete tied arch bridges; the initial geometric defects out plane have little influence on the analysis results of the concrete tied arch bridge;and initial geometric defects in plane have much more influence on the analysis results of concrete tied arch bridge than that of the out plane. The permissive arch axis departure in Chinese code can be relaxed properly,and the permissive arch axis departure rage out plane should be larger than that in plane.