AN EXPERIMENTAL STUDY ON RETROFITTING METHODS ON EXISTING REINFORCED CONCRETE COLUMNS WITH EXTERNAL LATERAL REINFROCEMENTS ANCHORED AT FOUR COLUMN'S CORNERS

Abstract

After Hyogo-Ken Nanbu Earthquake in 1995, seismic retrofitting on existing RC columns have been carried out, and steel jacket methods are mainly adopted. But these methods can't use in case of using spaces under superstructures for shops or store houses. So, we have developed new seismic retrofitting methods adopted easily on existing RC columns in above mentioned cases. In this method, external lateral reinforcements are arranged around existing RC columns and anchored at four corners of the column section by L-shaped steels. We carried out cyclic loading tests by using model columns retrofitted by this method, and confirmed that ductility ratio increases substantially by this method.