COMPARATIVE STUDY OF DESIGN OF FIBER CONCRETE SLAB ON GROUND USING TOUGHNESS METHOD AND RESIDUAL STRESS METHOD

The use of fibers as concrete reinforcement, replacing steel bars and meshes, is a practice increasingly used in the production of industrial floors, due to the economy and speed of the construction process. However, the design method needs to be adequate to avoid the appearance of undesirable cracks that could cause the interruption of the industry's operation. Recently, the design method of fiber concrete floors based on the residual stresses of the concrete, obtained after the cracking of the matrix, has been adopted by some design standards to replace the traditional method based on toughness. To compare the efficiency of the two methods, this study uses experimental results obtained in the literature and calculates the necessary thickness for an industrial floor with usual loading. The structural design indicates that the floor thickness is inversely proportional to the fiber content in the concrete, with the use of steel fiber reinforced concrete resulting in floors that are thinner than polymeric fiber reinforced concrete. The method based on residual stresses is more sensitive to variation in fiber content than the toughness method but resulted in higher values of thickness´s floor.