钢桁梁桥主桥设计比选及顶推施工抖振数值模拟研究

Design Comparison and Selection of Main Bridge of Steel Truss Bridge and Numerical Simulation Research of Incremental Launching Construction Buffeting

风致抖振响应对于桥梁顶推施工过程具有重要的影响。以张家口市宣化区胜利路桥新建工程为对象,开展主桥桥型设计比选研究,并采用ANSYS进行顶推施工抖振响应数值模拟。对主桥桥型设计进行比选,选择采用钢桥面系,带竖杆华仑桁架,钢-混凝土组合桥面铺装的简支钢桁架桥分幅桥梁方案。风荷载作用下,同一横断面处不同主桁处支座反力不同,对竖向支座反力而言,下游边桁架处最大,中间支座反力次之,上游支座反力最小。计算发现,在不考虑、考虑墩梁耦合效应两种状态时,下游边桁架支座反力峰值分别占恒载反力的10.5%和13%,中桁架支座反力峰值分别占恒载反力的5%、6.9%,上游边桁架支座反力峰值约占恒载反力的比例分别是6.5%、7.1%,可见墩梁耦合效应对该桥的抖振响应影响较小,可以忽略。结论可为今后类似工程设计与施工提供参考。

The wind-induced buffeting response has an important impact on the incremental launching constructionprocess of bridge.Taking the new construction project of Shengli road bridge in Xuanhua district,Zhangjiakou city as the object,the research on the design comparison and selection of the main bridge type is carried out,and the numerical simulation of the buffeting response during the incremental launching construction is carried out by using ANSYS.The design of main bridge type is compared and selected,and the scheme of simply supported steel truss bridge with steel bridge deck system,vertical pole truss and steel-concrete composite bridge deck pavement is selected.Under wind load,the reaction forces of different main trusses at the same cross-section are different.For vertical support reaction forces,the downstream side truss is the largest,the middle support reaction is the second,and the upstream support reaction is the smallest.It is found through calculation that,without considering or considering the pier beam coupling effect,the peak reaction force of the downstream side truss support accounts for 10.5%and 13%respectively of the dead load reaction force.The peak reaction force of the middle truss support accounts for 5%and 6.9%respectively of the dead load reaction force.The peak reaction force of the upstream side truss support accounts for about 6.5%and 7.1%respectively of the dead load reaction force.It can be seen that the pier beam coupling effect has a small impact on the buffeting response of the bridge and can be ignored.The conclusions can provide reference for similar engineering design and construction in the future.