Effect of cross-section size on flexural compressive failure of RC columns: Monotonic and cyclic tests

Abstract

The paper presents the results of 12 groups of geometrically similar reinforced concrete (RC) squared columns subjected to the combined loading of compression and bending. The performances and characteristics of the test RC columns are investigated in terms of the capacity of dissipated energy, the ductility capacity, the flexural capacity, the stiffness degradation as well as the rotation capacity of plastic hinge. The study also examines the influences of structural size, axial load ratio and the loading types (involving monotonic and cyclic lateral loading) on the flexural compressive failure characteristic of columns. The test observations indicate that the failure patterns of the tested columns are closely similar in spite of the difference in cross-sectional dimensions, and the flexural compressive failure of the columns presents obvious size effect. As the structural size of the tested RC columns increases, the dimensionless nominal moments (involving the nominal yield moment, the maximum moment and the ultimate moment corresponding to ultimate displacement), the ultimate drift ratio, the displacement ductility and the rotation capacity of plastic hinge decrease significantly. Moreover, a larger axial load ratio leads to larger load carrying capacity and weaker deformation capacity.