Avaliação experimental de pilaretes submetidos à flexo-compressão reta com variação da excentricidade

Abstract

The eccentricity of the applied load directly alters the behavior of reinforced concrete columns, influencing their load capacity, lateral displacements, and crack development. This work experimentally analyzed reinforced concrete short columns subjected to uniaxial bending and axial compression under different eccentricity levels. Five short columns, identified as P0, P25, P50, P75, and P100, corresponding to eccentricities of 0 mm, 25 mm, 50 mm, 75 mm, and 100 mm, respectively, were cast and tested. All models were produced with a cross-section of 10 cm × 15 cm, a height of 55 cm, and a design compressive strength of approximately 40 MPa. The results showed a reduction in load capacity as eccentricity increased, with failure loads of 415 kN (P0), 397 kN (P25), 372 kN (P50), 153 kN (P75), and 77 kN (P100). Early crack initiation and increased lateral displacements were also observed in models with higher eccentricities. Failure occurred predominantly in the region near the upper corbel. It is concluded that eccentricity caused a non-linear reduction in load capacity, with more pronounced losses starting at 75 mm, in addition to modifying the failure mode, which shifted from concentrated concrete crushing at lower eccentricity levels to more evident flexural cracking in the more eccentric models.