Analysis Of Interface Slip Effect Of Double Steel-Concrete Composite Beam

In traditional continuous steel-concrete composite beam, the crack in the concrete that suffers negative bending moment grows easily and the bottom steel flange may suffer "local buckling "or "overall buckling" and its bearing capacity weakens greatly. So the actual mechanical behaviour of the continuous beam conflicts with the "composite" purpose and limits its popularization and application in civil engineering. Double steel-concrete beam is a structure that besides the concrete roadway slab, there is a concrete bottom slab connected with the bottom steel flange through studs where this section suffers negative bending moment, which gives an effective way to solve this difficult problem. In this way, the compress stress in the bottom steel flange and web is shared with the "help" of the concrete slab, so their "burden" decreases largely, which improves the rigid flexibility and bearing capacity of the beam.This dissertation makes an exploratory research on the interface slip of the double steel-concrete composite beam under negative bending moment with the primary mechanical principle. The slip's formulas along the span direction are obtained and an example is used to make a comparison between the slip features of the double steel-concrete composite beam and the traditional continuous steel-concrete composite beam. A further analysis is made of the interface slip of the double steel concrete composite beam by the static load experiment of three double steel-concrete composite continuous beams model.The general Finite Element software ANSYS is used to make finite element models of the experiment's beams to analyse the nonlinear quality of the interface slips of double steel-concrete composite continuous beams. Corresponding to the double steel-concrete composite continuous beams'model, a single steel-concrete continuous beam is made, and the results of them is compared and analysed.The difference of deformation produced by the shrinkage of concrete and steel beam can have certain effects on the structure. In this dissertation, the formulas of the curvature of the composite beam's section produced by the shrinkage of concrete and steel beam of double steel-concrete composite beams under negative bending moment is obtained.Through the study, we can gain a preliminary insight into the mechanical behavior of the double steel-concrete composite beam, which provides a basis for further researches.