IMPROVEMENT OF STRENGTH DETERIORATION FOR RC COLUMNS USING LONGITUDINAL BARS WITH PARTIALLY LARGE LUG

Abstract

 In order to improve seismic performance, it is important to prevent rapid strength deterioration of RC columns. In this research, longitudinal bars with partially large lug were proposed for improvement of strength deterioration of RC columns, and the cyclic loading tests for RC columns were conducted. As the results, large lugs could control the occurrence of bond splitting cracks on RC columns surface, and bond characteristics of longitudinal bars with partially large lug was well-improved. Furthermore, by large lugs, both ends fixed boundary condition was maintained, and buckling length was prevented from becoming longer. In consequence, buckling of longitudinal bars became hard to occur, and rapid strength deterioration was prevented. Based on this result, pushover analysis of RC columns was conducted using buckling length as a variable. As a result, it was found that a general model of reinforcement buckling model wasn't able to reproduce strength deterioration with the same amplitude.