Structural performance of reinforced concrete exterior beam–column joint subjected to combined shear and torsion

Abstract

This article presents the results of an experimental study conducted in order to investigate the behavior of Type-I beam–column joints, where the beam was subjected to shear stresses due to combined effect of shear force and torsional moment (beam eccentric loading). Eight beam–column joint specimens were constructed and tested up to failure in order to better understand the complicated behavior due to combined loading transmitted from the beam to the column. The studied parameters were the eccentricity of beam load (torsional-moment-to-shear-force ratio M_t/Q), the configuration of beam side and compression reinforcing steel, the existence of the joint reinforcing stirrups, and the beam rigidity. Generally, the shear failure at the beam zone or at the joint panel was noticed to be the governing mode of failure for all tested specimens. The test results highlighted the importance of the configuration of both longitudinal side and compression reinforcing steel of the beam, where the inadequate embedded length of both of them into the joint panel including stirrups decreased the beam ultimate capacity but it kept the failure zone away from the joint panel. Finally, a three-dimensional truss model was presented and analyzed. The results of the three-dimensional model showed good agreement with the experimental findings.