A study of reinforced concrete corner columns after fire

This study investigated the behavior of corner columns under axial loading, biaxial bending and asymmetric fire loading. It is found that, under a longitudinal stress ratio of 0.1fc′, the residual strength ratios of the columns after fire loading show: (a) the 2 and 4 h fire loadings result in residual strength ratios of 67% and 57%, respectively; a 10% reduction on residual strength results as the duration changes from 2 to 4 h; (b) reductions in reinforcing steel ratio cause lower residual strength ratios; and (c) increasing the thickness of concrete cover causes lower residual strength ratios. It was also found that the temperature distribution across the cross-section is not affected by concrete cover thickness and steel ratio. The residual strengths can be used for future evaluation, repair and strengthening.