Gravity load-designed reinforced concrete buildings - Part II: evaluation of detailing enhancements

The seismic performance of a reinforced concrete (RC) building designed primarily for gravity loads was presented in the first part of this investigative study. Since the source of most of the structural damage is attributed to nonseismic details in the beam-column joint area, it was decided to examine the effects of improving these details in a marginal way, so that the seismic performance could be enhanced without resorting to a full seismic design. An extensive parametric study of the original buildings with refined detailing characteristics is carried out to ascertain effectiveness of the techniques to improve seismic resistance of gravity load-designed buildings. The important feature of the study is that the buildings are not redesigned for lateral forces, but only that detailing in critical regions is altered to achieve improved performance. This study may also be viewed indirectly as an inquiry into the effectiveness of retrofit strategies, should they be considered in real practice. The investigation also includes a cost evaluation of the various detailing schemes.