【摘要】 大跨度钢屋盖拆撑过程分析是目前大型工程建设中常遇到的施工力学问题,其求解的难点在于千斤顶工作机理、临时支撑与主体结构脱离和接触以及临时支撑回弹现象的模拟,尚未得到有效解决。基于通用有限元软件平台,利用其模块中的只压不拉杆单元和经典梁单元的独特性质,把这两个特性不同的单元并联在一起,通过耦合单元两端相应节点的自由度和修正单元的刚度,构造一种组合型千斤顶单元。引入刚化系数α和软化系数β,分别对杆单元和梁单元的轴向刚度进行修正,研究给出了α和β的取值范围,使组合千斤顶单元具有实际千斤顶的性质。建立了拆撑过程分析的千斤顶单元法,能够模拟拆撑过程中千斤顶和临时支撑的工作机理及其与主体结构之间的相互作用。算例分析表明,千斤顶单元法理论正确,应用方便,可以用于实际工程中拆撑过程的模拟,能够分析主体结构及临时支撑内力和变形的变化历程。更多还原

【Abstract】 Simulation of removing temporary supports of large-span steel roof is a construction mechanical problem frequently met in the construction of large structures recently.There are few approaches available to solve the problem effectively.Based on the finite element program,a jack element model used to simulate removing temporary supports of roof is presented and discussed.The jack element model is composed of a compression-only link element and a classical beam element,and the two elements are modified by two coefficientαandβ.The jack element model behaves as a real jack and it can simulate accurately the separation and contact between the main structure and the jack fixed on the temporary support,as well as rebound of temporary supports during the process of removing temporary supports.The results obtained demonstrate that the jack element model can be used to compute effectively and accurately the internal force and deformation of the steel structural roof and temporary supports during the construction process.更多还原