INFLUENCE OF THE COMPRESSIVE STRENGTH (FCK) IN THE ANALYSIS OF CONCRETE STRUCTURES DEFORMATION

Abstract

The Compressive strength (fck) has become the reference parameter in design of Reinforced Concrete Structures due to the ease of testing and the possibility of deducing other material properties from this one. The present paper seeks to analyze how the fck value influences the analysis of deformations of reinforced concrete structures. This verification will be done from the modeling of a hypothetical 10- floors building for the fck values of 30 MPa, 35 MPa, 40 MPa and 60 MPa. From the floor plan, the cross-section of the structural elements was pre-dimensioned; a plan of actions and loads according to ABNT norms was elaborated, and the modeling was carried out using the software SAP2000. Seven models of the same building were obtained, in which the influence of the fck in several parameters was evaluated, such as: the geometry of the pieces; the shortening of the pillars; the vertical displacement of beams and slabs and the horizontal displacements of the building. It was found that the modification of the compressive strength of the concrete contributed significantly to the determination of material properties and section geometry. The influences in the vertical and horizontal displacements were also observed, besides the final load of the pillars. It was concluded that the influence of fck value on structural analysis verifications occurs predominantly through the change in the final stiffness of the structural elements.