Cyclic response of non-seismically detailed interior RC beam–column connection with varying column tributary area

Abstract

The current paper presents a test of non-seismically detailed reinforced-concrete (RC) beam–column connections under reversed cyclic load. The tested specimens represented those of the actual mid-rise RC frame buildings designed according to the non-seismic provisions of the American Concrete Institute building code. The evaluation of ten existing RC frames was conducted to identify key structural and geometrical indices. It was found that there was correlation among structural and geometrical characteristics and the column tributary area. Hence, the column tributary area was chosen as a parameter for classifying specimens. The test results showed that specimens representing small and medium column tributary areas failed by brittle joint shear while specimens representing large column tributary areas failed by ductile flexure, even though no ductile seismic details were provided. The local bond deterioration and joint shear distress accounted for the pinched hysteretic loops. The detailed failure mechanism was investigated through a nonlinear finite element analysis. In the finite element analysis, the two-dimensional reinforced concrete plate element was used to model beam and column whereas the one-dimensional discrete joint element was used to model the interface between beam and joint face. The finite element analysis revealed that the joint shear failure of specimens representing a small to medium column tributary area resulted from the collapse of the principal diagonal concrete strut.