Publication: Effects of jacket height and jacket reinforcement on seismic retrofitting of reinforced concrete columns using concrete jacketing
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Date
2020-08-01
Authors
Zaiter, Ali
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Abstract
Reinforced columns may need to be jacketed as a retrofit measure to withstand earthquake damages, aging of concrete, deficient design, steel deterioration and construction errors. Concrete jacketing is one of the common and simple methods of retrofitting. Motivated by the above concern, experimental tests were conducted on a one-third downscaled interior column of a four-storey building (SMK Ranau) to evaluate the effectiveness of the jacket reinforcement and jacket height on the structural capacities of the retrofitted column. The jacketed columns were tested under monotonic loading to determine their ultimate capacities and to design their corresponding cyclic test. Under monotonic and cyclic tests, columns with jacket h/4 high had a significant increase in their lateral load capacity. Similarly, specimens with h/2 jacket high doubled the lateral load capacity of the reference column. The jacket reinforcement showed a minor influence on the lateral load capacity. The jacket reinforcement reduced the damage level in the jacket due to the lateral confinement of the jacket transversal reinforcement. Consequently, the jacket reinforcement increased the stiffness irregularity, damage and concrete spalling in the column above the jacket. The unreinforced concrete jacket of h/2 high almost doubled the lateral load capacity and lateral secant stiffness of the damaged columns. As there were paucity studies on the effect of jacket height and type of jacket reinforcement (reinforced or unreinforced), the findings in this study were believed to provide new insight towards the concrete jacketing forreinforced columns.