Experimental Study On Mechanical Properties Of Boxsection Bamboo-steel Composite Beams

Combination structure is the inevitable outcome of that human more fully consider structure safety, durability and good construction. Building construction materials and construction structure in the high performance is the important development direction of the composite structure, many new type composite structure emerge in this context. The bamboo-steel composite structure is a new type composite structure, cold-formed thin-walled steel and bamboo-based panel can form various bamboo-steel composite members such as composite slabs, composite walls, composite columns and composite beams, with structural adhesive or adhesive-screw hybrid joins.The paper presents a new type of box-section composite beams based on the research of the bamboo-steel composite structure. Two pieces of cold-formed thin-walled U-shape steel form the box section framework that bonding four pieces of bamboo plywood on the outside surface. Experimental study and theoretical analysis have been done on mechanical properties of them.Experimental study of flexural behavior and shear behavior of12composite beams was carried out by mechanical parameter of steel thickness, bamboo plywood thickness and sectional dimension. The failure process, failure modes and failure mechanism were analyzed, the change of strain in the steel sheets and bamboo plates at all levels loads and deflection of the development of composite beams were observed, the ultimate strength, flexural properties and shear properties of composite beams were explored.Based on bearing capacity superposition method, the paper presents the computational formula of flexural bearing capacity, shear bearing capacity and mid-span deflection in the ultimate state, the calculation results largely accord with the experimental results, and established the nonlinear finite element model of the composite beams, through the finite element analysis software ANSYS program, obtained the simulation data in the load test such as the stress, strain and deformation, which was in close compliance with relevant experiment result.The results indicate that box section bamboo-steel composite beams give full play to the strong bending deformation ability of bamboo plywood, ensure the stability of the specimen section, make steel plate into plastic development stage, to the full play of the strength of materials, composite effects are obvious, mechanical properties are good, can be used in construction engineering as the bearing capacity components. The research work of this paper may promote the development of bamboo-steel composite structure and offer some reference for its application.