Experimental investigation of strengthening of RC short columns using high strength reinforcement

Abstract

The design and construction of structures with fewer amounts of materials such as concrete and steel led the researchers to move towards the production and usage of optimum materials with higher resistance. High strength reinforcement (HSR) shares a higher ultimate resistance in addition to being economical which distinguishes them from the ordinary ones. Short columns, due to possessing a brittle behavior against cyclic loads, have caused serious damage in the past earthquakes, which can be considered as a major cause of building failure and collapse. In this research, three reinforced concrete short columns specimens are tested under constant axial load and cyclic lateral displacement. Since in the past earthquakes, the failure in the short columns was in the form of diagonal cracks and shear failure, therefor, in this study two new techniques are used to strengthen the diameter of the short columns against seismic loads. These techniques include externally bonded reinforcement (EBR) and near surface mounted (NSM) with HSR. The experimental results show that the above-mentioned strengthening techniques lead to a change in the cracks pattern and column failure. Also, EBR and NSM techniques show successful increase in the ductility, loading capacity, and the amount of dissipated energy.