A new confinement scheme for reinforced concrete columns using stainless steel or glass fiber reinforced plastic

Abstract

AbstractA new lateral confining method is proposed for reinforced concrete columns in this study. The new scheme incorporates additional lateral confinements that are placed outside conventional lateral reinforcements within cross section of a column. Stainless steel wires or glass fiber reinforced plastic (GFRP) rings have been employed as the additional confinement. A total of seven reinforced concrete column specimens have been tested to validate the proposed new scheme. Primary parameters in the test are vertical spacing and volumetric ratio of the additional confinements amongst others. Lateral hysteretic response shows that specimens with the newly proposed scheme exhibit no strength degradation up to 6% of drift ratio, the specimen without such scheme displays somewhat sudden degradation at 5% of drift ratio. Experimental results also indicate that displacement ductility and energy dissipation of specimens confined by the additional confinements are greater than those of specimen without such confinements. Margin of safety with reference to the code‐specified ductility is 1.6, 2.2, and 2.1 for specimen with no confinements, stainless steel wires, and GFRP rings, respectively. In addition, energy dissipation ability reveals that specimens with the confinements show up to 50% higher than the specimen without confinements. In all, experimental observation confirms that the present approach is promising to provide an additional confinement and ductility. It is thus expected that the suggested scheme can be applied to reinforced concrete columns and be particularly effective for those members with relatively large vertical spacing of conventional lateral reinforcements.