Steel and Concrete Structures

To improve the safety of existing structures, the Taiwanese government has been urging the seismic rehabilitation of old buildings in recent years. Among the numerous retrofit approaches, column-jacketing, which builds up building columns with enlarged sections and additional reinforcement, is the most widely used techniques currently in Taiwan. However, with the mechanism dominated by the flexural yielding of column base, the retrofit bonus drops quickly as the height of building increases. To provide additional strength, the concept of supplemental beams is introduced. By constructing additional beams between adjacent columns, the effectiveness of column jacketing could be improved. For verification, a full-scale, quasi-static experiment on three two-story concrete frames was performed in this study. Result of the experiment indicates that this technique can make a great enhancement to the seismic performance of the retrofitted frames.