Experimental Study on Seismic Retrofit of Reinforced Concrete Buildings using Combination of Column-Jacketing and Supplemental Beams

摘要

To ensure the seismic safety of existing buildings, the Taiwanese government has been pushing seismic retrofit of old buildings in recent years. In these projects, one of the most frequently used techniques is column-jacketing, which is accomplished by encasing existing columns with a thick cover of concrete along with addition of longitudinal and lateral reinforcement. While this technique only strengthens individual columns, the beams which these columns are connected to are left out. As resistances provided by these beams remain unchanged, these columns must act alone to resist lateral load, making this technique less effective. In this study, an adjustment is made by adding a supplemental beam between adjacent jacketed columns to providing additional resisting moments at the beam-column joints. To verify the effectiveness of the proposed technique, a quasi-static experiment was performed on three full-scale concrete frames at NCREE. Result of the experiment indicates that with this addition, the lateral strength of the frame is significantly increased, which will help improving both the stability of the building and the effectiveness of column jacketing during potential earthquakes.