Research and Application of Long-Span Orthogonal Inclined Space Tube Truss Structure to Improve Construction Accuracy Control

The roof structure of the middle group project of Xiaohe International Convention and Exhibition Center is the most complex part. It belongs to the discontinuous long-span orthogonal inclined space tube truss structure. It is divided into three parts: four corner roofs, glass roof of cross traffic corridor and central dome, the projected area of the corner top steel truss is 6 575 square meters, the span is 63 m, and the maximum span of the corner top oblique truss is 88.7 m, and a four-sided unequal height shape, the entire truss node is complex. There are various forms of steel pipe truss(single-curved arc, hyperbolic arc), variable diameter, welded ball, box-shaped cantilever, etc. The high-altitude workload is heavy, the construction period is short, and the professional cross-operation is frequent. In order to effectively reduce the construction difficulty and safety risks, and ensure the construction quality and progress, a combination of "floor(ground) assembly, block-by-block overall cumulative improvement + local floor in-situ direct bulk loading" is adopted for installation. In order to realize the control of the construction accuracy of the long-span orthogonally inclined space tube truss structure, the pre-camber setting before ground assembly was firstly studied, and the SAP 2000 software was used to simulate and analyze the staggered lifting, closing and unloading of the partitions, and calculate the lifting process accurately. At the same time, the nonlinear finite element simulation software simufact welding was used to analyze the welding deformation of each truss, and the pre-camber was considered by improving the deformation and welding deformation data; secondly, the virtual pre-assembly was realized by using 3D laser scanning technology during the ground assembly process; finally, in the lifting process, real-time control of the lifting synchronization was carried out to realize the research on the assembly welding from the ground and the control accuracy of the lifting process, which promoted the construction accuracy of the roof structure to reach the millimeter level, and avoided the rework of construction operations effectively and ensured that the entire roof space tube truss structure met the design requirements of the original state of the building.