Analysis Of Shear Mechanism And Test Research On Main And Secondary Beams Node Of U-section Steel-encased Concrete Composite Beams

This article puts forward a new type of steel-encased composite beam—U-section steel-encased concrete composite Beams. This kind of 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, theoretical analysis and nonlinear finite element analysis have been carried out in this article to study the main and secondary beams node of the new type composite beam. The details are as followings:1.Three specimens of this type of main and secondary beams node have been tested, failure modes of the three specimens, loading capacity, variation of load-strain of bolt connection plates and U—section steel—encased, variation of load-deformation are tested. From the test, the failure modes and shear mechanism of the main and secondary beams node have been gotten.2. Reasonable calculation model and calculation assumption are adopted. The reasonable and simple formula of shearing capacity of the main and secondary beams node are deduced. Compared the theoretical results with the experimental results, it is showed that the two results are corresponded, and the formula is accurate and reasonable. 3. The main and secondary beams node of U-section steel-encased concrete composite beams were analyzed using the nonlinear three-dimensional finite element method (FEM). And the distribution of stress contour figures, load-displacement curves and concrete cracks are acquired. The simulated results are compared to the test ones and they proved the correctness of the test results and theoretical ones. And on this basis, the correct joints details are acquired.4.Finally, construction design suggestions and study expectation of this new type of main and secondary beams node of steel-encased concrete composite beam are advanced according to the results of test research, theoretical analysis and nonlinear finite element analysis.