Development of Collapse Indicators for Risk Assessment of Older-Type Reinforced Concrete Buildings

This study examines the seismic collapse safety of older, non-ductile reinforced concrete building frames designed and constructed prior to the 1980s. The study considered idealized buildings with heights ranging from 4 to 12 stories. Performance was gauged using nonlinear dynamic analysis software considering nonlinearities associated with flexural yielding, shear failure, and axial failure. In addition to building height, the main variables were the relative strengths of columns and beams, and the relative shear and moment strengths in the columns. Incremental dynamic analysis was used to determine the probability of collapse for various combinations of the study variables. The results indicate that simple engineering indicators such as column-to-beam strength ratio and column flexural to shear strength ratio can be used to assess the collapse risk of older-type concrete buildings.