Calculation of Short-Term Deflection of a Composite Slim Floor with Single Span

Abstract

For the problem of stiffness calculation of a composite slim beam with reinforced concrete composite truss slab as floor slab, the short-term deflection of the slim beam is calculated and analyzed by theoretical and numerical methods. The result shows that the load-deflection curve is linear in the middle span of the composite slim beam, and the cross section of the composite slim beam is the ideal cross section. The stiffness of the composite flat beam can be calculated according to the linear elastic theory. The concrete area is converted into steel beam area by the method of conversion section, and then analyzed by the method of material mechanics. The elastic deflection obtained by the theoretical formula is in good agreement with the finite element analysis. The load – displacement curve of a single span composite slim beam is obtained by numerical simulation using finite element method. The curve is nonlinear. In front of the concrete cracking (the load reaches 25% of the failure load), the curve is accord with the theoretical calculation of the elastic curve, then the curve of the finite element calculation is along the horizontal deviation, especially when the load applied to 45% of the breaking load, then the offset value increase, this match the experimental analysis of the early stage of our research team is good.