Study On Capacity Of Temporary Support Structures Based On Three Dimensional Stability Analysis

The temporary support structure of building construction, building up with horizontal tube, vertical tube, oblique tube and other fittings, is widely used in civil engineering intended to bearing vertical loads from the upper structure and providing conditions and protections for constructions. With the development of economic and country construction, the structures with longer span and heavier height and variable architecture modeling bring forward higher demands of its practicality and safety. Therefore, it is necessary to research on its loading properties and computation methods of bearing capacity.In this article, a brief introduction of an new classification of temporary support structures was given, and the theoretical and experimental research results of temporary support structures were summarized from three aspects of computation theory, industry standards and program development. Then the research contents and methods of this article were presented.Computation model considering semi-rigid connections of different kinds of support structures was built and buckling mode of support structures were studied. Based on this, basic bearing elements were summarized, unit of frame and unit of truss were put forward.The frame support structure is simplified to single post model according to the characteristics of buckling mode. Theoretical calculation formula for the bearing capacity of frame support structure with x-bracing and without x-bracing were derived by energy method and balancing method, and the dimensionless parameters were proposed. According to a number of FE analysis, the fitting relationship among the bearing capacity, buckling model and dimensionless parameters were studied. The effective length factors in practical calculation formula were calculated by dimensionless parameter, and the computation table was given. Furthermore, examples calculated by this formula were compared with FE analysis and experimental results. Lateral restraint is a important factor of bearing capacity of support structure, displacements of vertical tube were reduced and buckling model were changed under lateral restraint according to the results of FE analysis. The correction coefficient of lateral restraint β was proposed, and the regularities of β change over stiffness and frequency of later restraint. Through analyzing the results of FE analysis, computation formulas for β were put forward.