AN EXPERIMENTAL STUDY ON EFFECTS OF EXTERNAL LATERAL REINFORCEMENTS ANCHORED AT COLUMN'S CORNERS FOR SEISMIC RETROFITTING

Abstract

Seismic retrofitting on existing RC columns have been carried out, and the steel jacket method has been mainly adopted. But the steel jacket method can't use where spaces under viaducts are used for stores and offices. So, we developed the new seismic retrofitting method which could be easily adopted at spaces being used under viaducts. In this method with external lateral reinforcements, lateral reinforcements do not yield if there is some spacing between extemal lateral reinforcements and column surfaces, or shear-to-moment-capacity ratio (V_yd/V_mu) is over 2.3. And flexural capacity which is larger than that of normal RC columns is obtained with a lower ratio of lateral reinforcement.