Seismic Risk Assessment of Gravity Load Designed Reinforced Concrete Frames Subjected to Mid-America Ground Motions

The infrequent nature of earthquakes in the Central and Eastern United States (CEUS), and the fact that none with intensity comparable to the New Madrid sequence of 1811-12 has occurred in the past century, have caused the earthquake hazard in the CEUS to be neglected until quite recently. The performance of reinforced concrete (RC) frames in the CEUS may be deficient if they are subjected to earthquakes that are believed to be plausible in the New Madrid Seismic Zone (NMSZ). This study presents a set of probability-based tools for seismic vulnerability and risk assessment of such gravity load designed (GLD) RC frames, and uses these tools to evaluate the seismic vulnerability of RC frames that are representative of the building inventory in Memphis, Tenn.-the largest population center close to the NMSZ. This evaluation indicates that traditional GLD RC frames have a substantial probability of suffering life-threatening damage or collapse in the event that they are subjected to earthquake demands stipulated in recent seismic design regulations such as ASCE Standard 7-05.