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The compressive strength of concrete according to certain codes can be based on the compressive strength of unconfined plain standard concrete cylinders tests at the age of 28 days. In this paper, the standard concrete cylinders were spirally confined with steel bars and with/without hooked-end steel fibers. The influence of the use of hooked-end steel fiber in spirally confined concrete with various pitches was investigated. It can be seen that the use of hooked-end steel fiber contributes significantly in improving both compressive strength and ductility of concrete. The compressive strength and ductility of steel fibered concrete also increase with the reduction of the spiral’s pitch.

A lightly reinforced column is commonly believed to be relatively brittle with a very low drift capacity. A research project has been undertaken to investigate collapse behaviour of such columns. The effect of variation of axial load ratio and longitudinal reinforcement ratio on flexural, yield penetration, and shear displacement as components of the drift capacity were observed. Interesting outcomes showed that lightly confined reinforced concrete was able to sustain gravity axial load considerably greater than the code recommendations. Moreover, the present shear predictions available are deficient for lightly reinforced columns, since they tend to overestimate the nominal shear strength of the column.

Lightly reinforced concrete walls are commonly found in low-to-moderate seismic regions such as Australia. While many theoretical analyses on lateral load-displacement of structural walls have been proposed and widely used, not many have been developed for lightly reinforced concrete walls. The lateral load-displacement behaviour and failure mechanism of lightly reinforced structural walls differ to those of heavily reinforced concrete walls, particularly in terms of tension stiffening effects, possible failure mechanisms and drift capacities. An analytical study on lightly reinforced rectangular concrete walls is presented in this paper. A parametric study was conducted to provide initial insight into the effect of four design parameters (aspect ratio, axial load ratio, transverse reinforcement ratio and longitudinal reinforcement ratio) on the ultimate displacement capacity of reinforced concrete walls. Two analytical models were developed to predict the lateral load-displacement behaviour of lightly reinforced walls consisting of a detailed wall model and a simplified wall model that provides a quick and conservative estimate for initial design checking purposes using displacement-based principles. Both models are shown to provide good agreement with experimental results in the literature. Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad Magazine of Concrete Research Volume 65 Issue 13 Seismic performance of lightly reinforced structural walls for design purposes Wibowo, Wilson, Lam and Gad

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