Efeito da continuidade no comportamento e na resistencia de lajes mistas com forma de aço incorporada

Abstract

The goal of this work was to evaluate the effects of continuity on the behavior and strength of composite slabs with ribbed decking. Six two span one-way prototypes, using Steel Deck MF-75 profiled sheeting, were built and tested in laboratory. The prototypes were placed over three equally spaced supports and subjected to a symmetrical loading. The effect of continuity was ensured by the presence and continuity of the steel sheeting, the wire mesh and the hogging reinforcement placedover the internal support. Throughout the loading tests, midspan deflections, end slips and strains in the ribbed decking and the reinforcing bars were measured. The test results showed expressively the gain in ductility and strength of the continuous slabs. In all tests, the failure mode consisted of a combination of shear bond and yielding of the reinforcement over the internal support. The comparative study with test results of single span slabs showed a significant increase in stiffness and load carrying capacity due to continuity. Since in practice the composite slabs are continuous over three or more supports, it would be only necessary to specify the hogging reinforcement.