• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.125-133
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• 2010

Researches and studies which have been conducted so far on external confinement of long span concrete columns have mainly concentrated on concentric loading. But, long span bridge concrete columns over the sea are mainly subjected to concentrated axial load, and at the same time lange amount of moment by eccentric load. This paper experimentally investigates the performance of externally confined high-strength concrete columns subjected to loading mechanism and evaluates the effectiveness of two confinement materials carbon fibre and high performance glass fibre. Twelve short columns with the same dimensions were cast and tested Six columns were reinforced with hoop bars, the remaining six columns were reinforced with spiral bars and wrapped with three layers of carbon failure and high performance glass FRP sheets. Test variables considered were the shape of internal reinforcement and strengthening materials according to loading location. The experimental results showed that eccentric load could obviously lower down the maximum failure load of FRP-confined concrete columns, compared with the columns under concentric load. And compared with the carbon FRP-confined reinforced concrete columns, high performance glass FRP-confined columns displayed a higher load capacity and ductility, when tested both concentrically and eccentrically.

• Journal of the Korea Concrete Institute
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• v.25 no.6
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• pp.667-674
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• 2013

Improving the earthquake resistance of buildings through seismic retrofitting using steel braces can result in brittle failure at the connection between the brace and the building, as well as buckling failure of the braces. This paper proposes a new seismic retrofit methodology combined with glass fiber sheet (GFS) and non-compression X-brace system using carbon fiber (CFXB) for reinforced concrete buildings damaged in earthquakes. The GFS is used to improve the ductility of columns damaged in earthquake. The CFXB consists of carbon fiber bracing and anchors, to replace the conventional steel bracing and bolt connection. This paper reports the seismic resistance of a reinforced concrete frame strengthened using the GFS-CFXB system. Cyclic loading tests were carried out, and the hysteresis of the lateral load-drift relations as well as ductility capacities were investigated. Carbon fiber is less rigid than the conventional materials used for seismic retrofitting, resulting in some significant advantages: the strength of the structure increased markedly with the use of CF X-bracing, and no buckling failure of the bracing was observed.