Cyclic response of RC beam-column joints strengthened with transverse steel bars and with C-FRP diagonal ties

Abstract

The use of additional bars, internally placed through drill holes, in external beam-column connections subjected to cyclic loading, as shear reinforcement is experimentally investigated.The presented experimental work includes tests of full-scale specimens with different reinforcement arrangements in the joint area, they are as follows: (a) the JB0V control specimen with two (extra) vertical side bars without shear reinforcement in the joint area and, (b) the JB0R joint, same as in the case of the control specimen, without the extra vertical bars, but with four additional steel bars that were placed in holes, which were drilled through the concrete of the joint body for this purpose, (c) the JB0VFX joint, the damaged control specimen repaired and strengthened with C-FRP diagonal ties (rope connections) through the joint area. The effectiveness of these additional bars and ropes as a shear reinforcement on the overall seismic performance of the tested joint is examined.A comparison between the test results of the examined specimens indicated that the applied retrofitting technique is appropriate for the enhancement of the overall hysteretic performance of the beam-column joints in terms of load carrying capacity, stiffness and hysteretic energy dissipation.