考虑主体结构与临时支撑相互作用的拆撑过程动力响应分析

ANALYSIS OF DYNAMIC RESPONSE OF MAIN STEEL STRUCTURE-TEMPO BRACE INTERACTION DURING REMOVING TEMPO BRACES PROCESS

结合天津市于家堡交通枢纽站房结构实际工程,基于有限元软件ANSYS详细模拟了实际施工过程,以精确模拟拆撑过程中各构件的内力分布。然后,采用降温法模拟切割连接构件进行拆撑的方式,对引起的动力响应进行了详细分析计算。分别选取反力最大的提升点与支撑点,研究主体结构与临时支撑体系在拆撑时的动力响应。结果显示:该拆撑方式引起的结构动力响应与支撑点反力、拆撑位移及结构刚度等因素有关;拆撑后的振动过程中,主体结构与临时支撑体系存在复杂的相互作用,而有限元方法可精确捕捉该过程;拆撑后的振动效应对提升拉索的影响最为不利,设计中应保证提升拉索及节点的可靠度;拆撑引起的振动效应对临时支撑结构的影响要大于主体结构,支撑体系设计阶段应充分考虑整个施工方案,提高临时支撑的可靠度,而不是仅满足静力强度。

The erection process simulation of Yujiapu railway station building in Tianjin was conducted based on ANSYS software package to exactly simulate distribution of component internal force. Then cooling method was adopted to simulate removing tempo brace process by cutting the connected members and dynamic response was computed in detail. The hoisting point and supporting point,at which the reaction force were the biggest,were selected to investigate law of dynamic response. It can be concluded that the dynamic response induced by method of removing tempo brace was influenced by reaction force,removing tempo brace displacement,and structural stiffness;finite element method could capture the dynamic rule of main structure and temporary supporting system that interact with each other; dynamic response induced by removing tempo brace was most unfavorable for hoisting cables,the dynamic coefficient was far greater than that known before and reliability of cables and joints should be ensured; the influence of dynamic response on temporary support system was greater than that on main structures,so the temporary support system should be designed by considering the whole construction process,rather than meeting static strength requirement only.