Experimental studies on the behaviour of non_seismically detailed reinforced concrete column

Abstract

Post earthquake and experimental research have shown that old reinforced concrete structures which are designed based on non-seismic details are vulnerable to shear failure during earthquakes. Shear failure can lead to a reduction in building lateral strength, change in inelastic deformation mechanism and loss of axial load-carrying capacity. The loss of axial load-carrying capacity in the columns is extremely dangerous as once the axial strength of the column drops below the designed axial load of the column, all excess loadings will be transferred to the surrounding columns, hence leading to a propagation of collapse. Recognizing the risk posed by column shear failure, engineers evaluating existing buildings or designing new buildings for seismic effects aim explicitly to avoid column shear failure. Engineering models for column shear strength that includes uncertainty measures are needed so that safe yet efficient evaluations and designs can be achieved. For evaluating older existing reinforced concrete buildings, models that are sensitive to the details that are prevalent in these buildings are needed. This research focuses on the mechanism of the axial strength degradation of non-seismically detailed columns under reverse seismic loadings and tests were designed to observe the behaviour of these columns. The results from these tests provide data on shear strength, the behaviour of columns under shear failure and the degradation trend of axial strength.