Experimental study of strengthening of RC frames with column retrofitting

Abstract

Recently, researches related with strengthening have been increased. In most of these studies, strengthening of reinforced concrete frames with inadequate earthquake resistance was searched. However, it is known that there are buildings with inadequate earthquake resistance as well as buildings with both inadequate earthquake resistance and inadequate axial load bearing capacity. A 1/3 geometric scaled reinforced concrete frame with inadequate earthquake resistance and inadequate axial load strength modeled as a sample building was strengthened with column retrofitting and tested under vertical and lateral loads. In this study, two 1/3 geometric scaled specimens were tested under the effect of reversible repeatable lateral loads simulating earthquake. One of these samples is a bare reinforced concrete frame representing buildings with inadequate earthquake resistance and axial load strength as well as including building defects without any strengthening which are frequently encountered in our country. The second experiment element was constructed in order to represent the buildings which necessitate strengthening due to earthquake loads and axial loads. In this specimen, the columns were strengthened by retrofitting from three sides. The hysteresis curves, envelope curves, rigidity, ductility and consumed energy graphs of these tested elements are given and the differences between them were investigated and interpreted. In the final section, the experimental results obtained were evaluated, interpreted and suggestions were made.