The failure of reinforced concrete columns is one of the major causes of collapse in framed structures during an earthquake. Therefore, to achieve an appropriate margin of safety, it is critical to design structures that prevent columns from losing their load-carrying capacity. To control premature structural failure, it is preferable to control plastic hinge formation in beams rather than in columns to avoid soft story mechanism and a decrease in the energy dissipation capacity of the structure. Collapses because of local damage to columns, the major gravity load-bearing elements of framed structures, produce the need for ductile detailing of columns for resisting lateral ground motions.

Using the displacement ductility capacity is a good way to identify the deformation capaci...[ Read more ]

The failure of reinforced concrete columns is one of the major causes of collapse in framed structures during an earthquake. Therefore, to achieve an appropriate margin of safety, it is critical to design structures that prevent columns from losing their load-carrying capacity. To control premature structural failure, it is preferable to control plastic hinge formation in beams rather than in columns to avoid soft story mechanism and a decrease in the energy dissipation capacity of the structure. Collapses because of local damage to columns, the major gravity load-bearing elements of framed structures, produce the need for ductile detailing of columns for resisting lateral ground motions.

Using the displacement ductility capacity is a good way to identify the deformation capacity of reinforced concrete (RC) columns under seismic attack. In general, the capacity is evaluated with force-displacement response, where equivalent curvature distribution approaches and plastic hinge length models generate the response from the sectional moment-curvature. The tools focus on minimising computational effort, predicting approximate force-displacement responses and determining the ultimate deformation capacity of RC columns. However, there is no widespread agreement on how to define the ultimate limit stage, so the determination of plastic hinge length is ambiguous.

This thesis proposes a modified equivalent curvature distribution approach that involves the development processes of plastic hinge formation. It outlines the procedures to generate the force-deflection responses of rectangular RC columns, proposes a modified equivalent plastic hinge length model and discusses the numerical evaluations with experimental results. Other existing approaches are also considered to investigate the effectiveness of the proposed approach. The predicted backbone envelopes of the force-deflection responses correlate well with the experimental results in literature.