2800t悬挑桁架安装和落架的数字化模拟分析

DIGITAL SIMULATION OF INSTALLATION AND TEMPORARY SUPPORT REMOVAL OF 2 800 TONS CANTILEVERED TRUSS

悬挑桁架的高空安装和整体落架是工程施工中的重难点。工程地上部分的悬挑桁架总质量约2 800余吨,悬挑长度约13 m,采用独立支撑架高空原位安装,总落架结构面积约10 000 m2,有16部胎架参与落架。根据落架原则,结合现场整体施工进度,悬挑结构的落架方式为"分区、分级、等值"落架。根据主体结构的核心筒,将悬挑钢结构参与落架的16个落架点分成两个区,分批等值落架,每一级的落架量为10 mm。为准确模拟施工过程中构件的力学性能,使用有限元分析软件MIDAS-GEN,模拟分析悬挑桁架安装和落架施工的全过程。根据真实施工情况,利用多个落架荷载步模拟实际每一步落架工况,最后分析数字化落架结果,评价实际落架对主体结构的影响。数字化模拟分析中考虑了悬挑结构与支撑结构的相互作用,使计算更加接近实际。

The installation and temporary support removal of a cantilevered truss are the importance and difficulty in the construction of a steel structural project. Cantilevered truss of the project on the ground weighted about 2 800 tons, cantilevered length was about 13 meters, and the independent support upper air in situ installation was used. The total temporary support removal construction area was about 10 000 square meters, and 16 bed-jigs were used to do temporary support removal. According to temporary support removal principle, combined with field overall construction schedule, cantilevered structure temporary support removal way was ＂ zoning, classification and equivalent＂ temporary support removal. According to the main structure of the core tube, the cantilevered steel structure involved in temporary support removal 16 temporary support removal points were divided into two zones, then equivalent and batch removals were done. The removal amount of each level was 10 rnm. To accurately simulate the components mechanical properties of the construction process, the finite element analysis software MIDAS-GEN was used to simulate cantilevered truss install and temporay support removal construction process. Based on the true construction, multiple load steps were used to simulate actual conditions of each temporary support removal step, finally, the digital temporary support removal result was analyzed and the actual temporary support removal impact on the main structure was evaluated. The interaction between the cantilevered structure and the support structure was considered in the simulation, so the calculations were more realistic.