杆件局部失稳对钢桁架拱桥整体稳定性的影响  

Influence of Local Instability of Members on Overall Stability of Steel Truss Arch Bridge

作　　者：孔丹丹 于晓坤[1] 郝向炜[2] 于莹 顾子丰 Kong Dandan;Yu Xiaokun;Hao Xiangwei;Yu Ying;Gu Zifeng(Northeast Forestry University,Harbin 150036,P.R.China)

机构地区：[1]东北林业大学土木工程学院,哈尔滨150036 [2]东北林业大学,哈尔滨150036

出　　处：《东北林业大学学报》2021年第7期116-121,共6页Journal of Northeast Forestry University

基　　金：黑龙江省交通运输厅科技项目(2020HLJ018)。

摘　　要：以某城市钢桁架拱桥为研究对象,采用板单元、梁单元、桁架单元等模拟整体有限元模型,分析钢桁架拱桥局部杆件弹塑性稳定性的特征值;通过改变风撑、斜撑、拱肋、吊杆数量及拱肋的刚度和矢跨比等参数,分析成桥状态下局部稳定性对钢桁架拱桥整体稳定性的影响。结果表明:(1)经计算结构的失稳临界值,杆件局部失稳是钢桁架拱桥失稳的主要影响因素,局部杆件受力能较好地反映结构稳定性承载力。(2)增加风撑结构的数量可以显著提高结构的稳定性;但当风撑数量足够时,继续增加风撑结构的数量,结构的稳定性并不能得到很大的提高;斜撑的设置对整体稳定性有很大的影响,特别是"K"和"X"斜撑对结构稳定性的影响非常显著。(3)风撑和拱肋刚度变化对结构的稳定性影响较为显著,吊杆刚度变化对结构的稳定性影响不大。(4)当矢跨比为1.0/4.0~1.0/5.0时,失稳位置出现在风撑位置;矢跨比为1.0/5.5~1.0/6.0时,失稳位置出现在拱肋弦杆位置;矢跨比主要通过影响局部位置杆件的受力状态影响结构整体的稳定性。Taking a certain urban steel truss arch bridge as the research object,we used plate elements,beam elements,truss elements,etc.to simulate the overall finite element model,and analyzed the characteristic values of the local members of the steel truss arch bridge under the elastic-plastic stability.By changing the number of wind bracing,diagonal bracing,arch rib,the quantity and stiffness of suspenders,vector-span ratio and other parameters,we analyzed the influence of local stability on the overall stability of the steel truss arch bridge in the completed state.The results show that:(1)After calculating the critical value of structural instability,local instability of members is the main factor influencing the instability of steel truss arch bridges,and the force of local members can better reflect the stability and bearing capacity of the structure.(2)Increasing the number of wind bracing structures can significantly improve the stability of the structure;but when the number of wind bracings is sufficient,continue to increase the number of wind bracing structures,and the stability of the structure cannot be greatly improved;the setting of diagonal braces will affect the overall stability.The performance has a great influence,especially the"K"and"X"diagonal braces have a significant influence on the structural stability.(3)The changes in the stiffness of wind bracing and arch ribs have a significant effect on the stability of the structure,while the changes in the stiffness of the suspender have little effect on the stability of the structure.(4)When the rise-span ratio is 1.0/4.0-1.0/5.0,the instability position appears at the position of the wind brace;when the rise-span ratio is 1.0/5.5-1.0/6.0,the instability position appears at the position of the arch rib chord.The ratio mainly affects the stability of the structure as a whole by influencing the force state of the members at the local position.

关 键 词：钢桁架拱桥 局部稳定性 稳定系数 失稳模态 

分 类 号：U443.35[建筑科学—桥梁与隧道工程]