Investigation on the effects of L-shaped FRPs for strengthening of exterior RC joints to relocate the plastic hinge place away from the column face

In a RC structure subjected to column removal, beam-column joints compromise one of the critical regions. According to analysis, after column removal (result from deliberate attack, vehicle impact, natural causes, etc), in some cases, plastic hinges will be formed and rotation of some of this hinges exceed acceptance criteria. An appropriate procedure to decrease plastic hinges rotation is FRP strengthening. This paper presents the results of a numerical study performed to evaluate the ability of L-shaped CFRP sheets in preventing the plastic hinge formation at the face of the column and decreasing the plastic hinge rotation in exterior RC joints. Two plain/CFRP-retrofitted joints of a typical intermediate RC frame were modeled in ANSYS and loaded under monotonic loads to failure. the results show that L-shaped strengthening with CFRPs can decrease plastic hinge rotation and effectively relocate the plastic hinge away from the column face