【摘要】 目的对一座下承式钢箱系杆拱桥拱脚进行有限元分析,了解拱脚处应力分布规律,对该处构造合理性做出综合评价.方法根据圣维南原理,运用三维有限元程序Midas/Civil,从总体杆系计算模型中提取钢拱圈节段内力,通过虚拟梁和刚性面加载到局部模型上,进行拱脚节点部位空间有限元分析.结果拱脚结点内部的应力绝对值都较小,应力值较大的区域出现在拱肋与拱脚结点连接处、预应力锚点处,但上述应力值均没有超出混凝土抗压设计强度.在拱肋与拱脚连接处周围出现了拉应力,且有小部分区域的拉应力超过混凝土抗拉设计强度,特别是混凝土实体的角点处.结论拱脚结点以纵桥向受压为主,结点内部应力分布较均匀,应力集中现象出现在拱肋与拱脚结点相接处和预应力锚点处,施工中应注意刚度突变处以及预应力锚点等应力集中区域的施工质量,并进行局部钢筋网的加强,以便于应力的分散.更多还原

【Abstract】 In order to learn the stress distribution law and comprehensively evaluate the construction rationality of arch spring,the arch spring of one through-type steel-box tied arch bridge was analyzed.According to Saint-Venant Principle,the segment internal forces of steel arch ring from the calculation results of whole member model using 3-d finite element software Midas/Civil.Then the internal forces of arch spring were applied on local model through virtual beam and rigid surface,and local spatial model of arch spring was analyzed by using finite element method.The stress values of arch spring are lower and the regions with relative higher stress values are conneced between arch rib and arch spring,as well as anchorage zone,but all of the stress values are not exceed the design value of concrete compressive strength.There are tensile stresses in the connection between arch rib and arch spring,and the tensile stress values of small region exceed the design value of concrete tensile strength.The results show that the arch spring mainly bears longitudinal compression and the stress distribution is more uniform.The stress concentration phenomenon exists on the connection of arch rib and arch spring and prestressed anchorage zone.In the arch bridge construction,the construction quality of these regions should be guaranteed,which exist stress concentration.Moreover,the mesh reinforcement of these regions should be strengthened in order to disperse stress.更多还原