In this paper, new seismic retrofitting methods by external reinforcement is proposed. Main objectives of this technique is to increase the flexural strength of existing RC columns detailing weak column and strong beam joint type in RC connection and to ensure the seismic performance subjected to large deformation under cyclic lateral loads. The proposed methods herein is the combined the steel plates and continuous fiber sheets with grout mortar layer. Furthermore, additional external longitudinal bar through the beam-column joint which is encased in mortar layer. These members are connected with the existing RC columns together with bonded anchor.
In order to investigate the increasing flexural strength, the lateral cyclic loading tests were conducted for the five specimens with two different joint type of exterior and interior columns which the different mechanical properties of beam were planned, and respectively, compared them with the original RC frame. Test results shows that this method was very effective in enhancing the flexural strength of column. But its strength for all specimens of interior columns were almost similar, because hysteresis characteristics were hardly affected by mechanical properties of beam.
