拱桥吊杆等刚度设计及其动态响应分析

A study on equal stiffness design of arch bridge suspenders and their dynamic response analysis

针对中承式拱桥结构中短吊杆处较易率先疲劳破坏的情况,分析各个吊杆处的刚度差异。以某中承式钢管混凝土拱桥主跨吊杆为研究对象,通过调整吊杆单元的弹性模量对吊杆进行等刚度设计,采用车桥耦合迭代的计算方法,得到车辆荷载作用下吊杆的应力响应曲线并计算冲击系数。对拱桥吊杆的动态响应进行分析并与初始模型情况比较,结果表明:等刚度模型短吊杆应力有明显下降,各吊杆间应力差异降低;吊杆的冲击系数降低,长短吊杆间冲击系数之差减小幅度达到50%;不平度等级对冲击系数的放大作用不随刚度调整而改变。说明对拱桥吊杆进行等刚度设计能够有效的平衡吊杆受力情况,使吊杆受到的冲击作用较为均匀,提高吊杆耐久性,为实际工程应用提供依据。

Short suspenders in a half-through arch bridge structure are easier to be ruined firstly.To solve this problem,the stiffness difference of each suspender departments was analyzed.Taking a half-through concrete-filled-steel-tube arch bridge as the study object,the elastic modulus of suspender element was adjusted to make the equal stiffness design.The stress response curve of suspenders was obtained and the impact coefficient was calculated under the vehicle load with the vehicle-bridge coupling method.Compared with the initial model,dynamic response of arch bridge suspenders was analyzed.The results show that the stress of short span is apparently decline in an equal stiffness model and the stress difference of each suspender is reduced;the suspender impact coefficient is reduced and the difference between short and long suspenders is reduced as high as 50%;the amplification of roughness level on impact coefficient does not change with stiffness adjustment.It is shown that equal stiffness design for arch bridge suspenders can effectively balance the suspender stress,and make the impact effect more uniform.The durability of suspenders is enhanced to provide a base for practical engineering application.