Effectiveness of Textile Reinforced Mortars (TRM) on Shear Strengthening of Seismically Deficient RC Beam-Column Joints

Textile reinforced Mortar (TRM) was experimentally investigated in this study as a new material for strengthening and seismic retrofitting of RC beam-column joints. The results of TRM-upgraded joints were then compared with that of Glass Fiber Reinforced Polymer (GFRP)-strengthened joint specimens. Three as-built joint specimens were constructed with non-optimal design parameters (inadequate joint shear strength with no transverse reinforcement) representing extreme case of pre-seismic code design construction practice of joints and encompassing the vast majority of existing beam column connections. Out of these three as-built specimens, one specimen was used as baseline specimen (control specimen) and the other two were strengthened with TRM and GFRP sheets respectively. All these three sub-assemblages were subjected to quasi static cyclic lateral load histories so as to provide the equivalent of severe earthquake damage. Response histories of control and strengthened specimens were then compared. The test results demonstrated that TRM can effectively improve both the shear strength and deformation capacity of seismically deficient beam-column joints to an extent which is comparable to the strength and ductility achieved by well-established GFRP-strengthening of joints.