Retrofit of RC square short columns

There exist many reinforced concrete short columns that are vulnerable to brittle shear failure as repeatedly demonstrated during recent severe seismic events. Due to the large scale of the problem, it is important to investigate the behaviour of short columns and approaches to their retrofit. The objective of this research program is to evaluate the performance enhancement of short reinforced concrete columns with high and low transverse steel content when retrofitted using fibre-reinforced composites. Seven reinforced concrete short columns were designed and tested under lateral cyclic loading and constant axial load. Carbon or glass fibre-reinforced polymers were used to strengthen the short columns.It is found that short columns, even ones designed according to current codes, suffered brittle shear failures. It is demonstrated experimentally that it is possible to strengthen the shear resistance of short columns such that a flexural ductile failure occurs by developing plastic hinges at both ends of the column. Anchoring of the fibre wraps to the columns was found to be effective in increasing the shear resistance and energy dissipation capacities of the columns.