Reforço à flexão de lajes de concreto armado com a adição de uma camada de concreto

Abstract

Concrete structures require periodically maintenance, in order to preserve theirs structural and aesthetics properties. Once the behavior of concrete structures appear to be inadequate, due to degradation or by the change of the type of loading, the intervention becomes mandatory in order to rehabilitate them. Actually, there are different types of techniques available for structural strengthening, each technique has advantages and disadvantages, thus the selection of the proper technique that will be used depend on the technical and economic requirements for the specific case under study. One of the available strengthening techniques of the reinforced concrete slabs is by adding a concrete overlay over the compressed face. Within this context, this work presents analytical methodology to calculate the resistance of strengthened slabs, taking into account the concrete compressive strength, the overlay thickness and the existing slab deformations before the intervention. To validate the method proposed, it was applied to slabs tested by other researchers and the comparison of results confirmed its suitability. In order to better understand the behavior of strengthening slabs, were made numerical analyzes based on the Finite Elements Method, taking into consideration the concrete cracking, the existing slab deformation due the dead loads and the used of shear connector crossing the interface concrete overlay-slab. Finally, based on the results of this study, recommendations for the slabs strengthening project using this technique will be made.