The Experiment And Analysis Of Ultimate Buckling Strength In Composite Tube Truss

Compared with composite beam, the composite truss had some advantages including lighter self-weight, greater rigidity and lower fabrication cost. Compared with steel truss, its ductility and entirety were better. The composite trusses possess extensive application foreground and eminent economic benefit in the field of bridge engineer and high-rise building. The composite tube truss is one form of the composite truss. It is composed of concrete slab and tube truss which is made by steel pipe. The bolt will connect the concrete slab and the tube truss to a whole. With the development of intersecting line of CNC cutting technology, made a tube truss become more and more convenient. In a word, research the behavior under bending of the composite tube truss may be valuable to the Engineering applications.Go ahead in this basis, this paper completed experimental study of two composite truss with different thickness of concrete slab under static concentrate vertical loads. In the test, some phenomenon such as the deformation performance in various stages, the state of the component under the loads and the damaging shape was observed. By the measured data, researchers analyze the distribution of the strain and the stress in the surface of concrete slab, tube truss and the cross-section of the composite tube truss.This paper adopted nonlinear finite element method to simulate the whole loading process from one of a test composite tube truss provided by researchers. It can be obtained clearly that the result is accurately enough and can satisfy the demands of engineering. On this basis, this paper designed a sample which span is 15 meters. The load-deformation curve, failure mechanism and the distribution of the stress on the components at the time of the distribution was analyzed in details. Then this paper designed analytical samples of composite tube truss. Some dominant parameters are analyzed on the influence of ultimate buckling strength, such as the thickness of concrete slab, concrete strength, high-span ratio of the truss, yielding strength of steel and so on. Then based on the calculation method of the composite beam, the ultimate buckling strength of composite tube truss with complete shear connection was derived, and it put forward the corresponding formulas and explained by calculating examples. By comparing the calculating examples and the results of finite element analysis, it can be obtained clearly that the result of the ultimate buckling strength which is calculated by the method in this paper and the result of finite element analysis is accurately.At last the conclusions were summarized and the questions, which needed to be experimental investigation and to be analyzed, were listed.