上承式钢管混凝土拱桥动力特性分析

为研究上承式钢管混凝土拱桥的动力特性,以大型有限元计算软件ANSYS为平台,对跨径为252 m的上承式钢管混凝土拱桥——千岛湖1号特大桥建立了空间有限元模型,进行了动力特性分析。通过对前十阶频率和振型的分析,得出结论:面内基频一般较面外基频大,尤其是大跨度拱桥,应注意保证拱的横向稳定性;桥面系的面内振动与拱肋基本同步,桥面系的面外振动受桥面系与拱肋之间联结形式的影响较大,采用立柱或刚性吊杆联结时,二者振动基本同步;通过收集到的大量钢管混凝土拱桥的结构型式和基频计算结果,可得出钢管混凝土拱桥基频随跨径的变化趋势,并由此回归出频率对于跨度的公式,当缺少实测资料时,可作为工程设计中的参考依据。

On Dynamic Characteristics of Deck-type CFST Arch Bridge

In order to studying the dynamic characteristics of deck-type CFST arch bridge,the space finite element model of this type,Qiandaohu No.1 Great Bridge with 252 m span is established to make dynamic characteristic analysis with large-scale computation program ANSYS.Through the analysis of the first ten frequencies and vibration,the relevant conclusions can be drawn that the in-plane frequency is generally greater than the out-of-plane frequency,and especially,the large span arch bridge should pay attention to ensure the lateral stability of arch.The in-plane vibration and arch rib are consistent,and out-of-plane vibration is influenced largely by the connection type of deck system and arch rib.When using connection of stand column or rigid suspender,the two vibrations are synchronic.Through large amounts of data collected about structure types and frequencies calculations results of CFST arch bridge,a trend of fundamental frequency and the formula of frequency to span can be obtained,which can provide references for the engineering design when having no measured data.