Study On Flexural Behavior Of The Light Steel-gypsum Based Self-leveling Floor Compound Composite Beams

Light steel-gypsum based self-leveling floor compound composite beams is a new type of lightweight composite beams consisting of Light steel joists connected to composite slab based profiled steel sheet, interfacial agent and gypsum based self-leveling floor compound by self-drilling screws. This paper primarily researchs flexural behavior of the light steel-gypsum based self-leveling floor compound composite beams by the experimental study and theoretical analysis, and the corresponding proposed design method is put forward.The flexural performance of three full scale experimental models which have different types of shear transfer(steel wire gauze, Z tab shear transfer) at construction stage and serviceability limit stage was studied. Meanwhile the trial device, test method and full test course as well as the analysis of test data are introduced in details. According to test results, the working and destruction mechanism of Light steel-gypsum based self-leveling floor compound composite beams were analyzed for the first time. Then, the study shows shear transfer has little effect on flexural stiffness at serviceability limit stage and ultimate flexural capacity.Finite element method based on ABAQUS program considering geometric large deformation, materials and boundary nonlinear was used to simulate the flexural performance of test models at different stages. It was found that the computer analysis and experimental results are in good agreement with each other. Parameter analysis was carried out to mainly determine the effect of spacing of screws, height of floor joists, thickness of floor joists, gypsum based self-leveling floor compound thickness and the strength of steel members. The analysis indicates when the screw spacing is less than 126 mm or greater than 630 mm, and changing the height and thickness of floor joists, which have more significantly influence to flexural stiffness at serviceability limit stage and ultimate flexural capacity.At last, based on the experiment and nonlinear finite element analysis, the design method of flexural stiffness at serviceability limit stage and ultimate flexural capacity considering the coefficient η of height-thickness ratio of floor joists and spacing of screws are proposed with partial shear connection. Compared with the ABAQUS results, the proposed method indicates high degree of accuracy.