张弦网壳结构索张拉模拟计算及试验研究

NUMERIAL SIMULATION AND EXPERIMENTAL STUDIES ON CONSTRUCTION PROCESS OF RETICULATED SHELL-STRING STRUCTURE

施工张拉控制是张弦网壳结构的关键技术之一,提出采用控制索原长的反分析方法追踪结构施工整个过程。首先,通过控制索在预应力状态下的张拉力求出零状态和索原长,并同时获得预应力态下所有单元的内力。在此基础上,通过控制每一级张拉索的原长,进行非线性有限元迭代计算,可求出索在分级分批施工时的控制力,并用VC++6.0编制相应的计算程序。这一方法有效地避免了通用有限元需要反复试算,计算繁琐的缺点。最后,以张弦网壳结构模型为试验对象,按分级分批张拉的方式模拟结构的现场施工,并跟踪施工过程中杆件单元的应力状态。结果表明,数值模拟计算与试验值吻合较好,计算结果可靠,该方法能精确模拟结构的施工成形过程,且在整个过程中,每根索只需张拉一次,简化了施工工艺。

The construction tension control is a key technique for reticulated shell-string structure. The whole construction process of structure was traced by inverse analysis method based on the theory of controlling the original length of cable. First, the initial status and the initial cable length were calculated by means of controlling the cable force and the internal force of all members in the pre-stressed state were obtained at the same time. Then, the tension force at each grade and batch was obtained, via controlling the initial cable length of every grade and calculating by the iterative algorithm of nonlinear finite element. A piece of software calculating cable tension was built by using VC ＋＋ 6.0 program, which avoids the repeated calculation in the large current FEM program. Finally, an experiment on the reticulated shell-string model was done, with which the construction was simulated by the multi-times and batching tensioning method, which traced the stress state of bar member during construction process. It was shown that the calculation results by the proposed method were matched the experimental results and the method could accurately simulate the shape-forming process of structure, cables were tensioned only once and the construction was simplified.