Load Bearing Behavior And Test Research Of Simply Supported U-section Steel-encased Concrete Composite Beams

The new type of steel-encased composite beam takes thin steel plate into the cold bending directly or use the cold bending thin-walled steel welded U-shaped section,and then fill concrete in the section of the U-shaped as internal T-shaped beam ribs.Flange acts cast-in-situ concrete board members. The web and concrete flange floor are integrated by shear connectors and work together.Test research, theoertical analysis and computer simulation have been carried out in this article to sutdy two kinds type of simply supported composite beam.The details are as followings.(1)six specimens of this type of beam have been tested(shear connector includes two kinds:one kind is stud welding on both sides of the plate on the flange and innersplitring welding in the u-shape section,another kind is angle steel welding only on both sides of the plate on the flange).two kind of shear connectors'effects,failure modes of the six specimens,loading capacity,variation of load-strain of bottom plate,variation of load-deflection and strain distribution along section are tested.From the test,the failure modes and behavior of this new type of composite beam have been gotten.(2) According to the test results, reasonable calculation model and calculation assumption are adopted. The flexural strength of normal section, deformation calculation formula, vertical shearing capacity,longitudinal shearing capacity and longitudinal slippage of the steel-encased composite beam are deduced,and compared with the experimental results, the reasonable and simple formula used in engineering calculation are deduced.(3)Numberical simulation is conducted by nonlinear finite element methods.And the stress contour figures and load-displacement curves are acquired.Two kind of shear connectors'effects are compared,and the simulated results are compared to the test ones and they proved the correctness of the test results and theoretical ones.On this basis,some parameters are analysed and related conclusions are acquired.(4) Finally,study expectation of this new type of steel-encased concrete composite beam are advanced according to the results of test research and theoretical analysis.