UCLA

This study is focused on assessing the seismic resilience of two 42-story reinforced concrete dual system tall buildings designed by different methods. A systematic rating approach based on the United States Resiliency Council (USRC) Seismic Rating procedure is used as the resilience metric. The two buildings were developed as part of the Pacific Earthquake Engineering Research (PEER) Institute’s Tall Building Initiative (TBI) project. Both buildings were designed based on an assumed site location in Los Angeles, California. One variant was designed using prescriptive code provisions and the second using the Los Angeles Tall Building Structural Design Council (LATBSDC, 2008) Guidelines. The Seismic Performance Prediction Program (SP3) is used to perform the building rating analysis based on the FEMA P-58 methodology (FEMA, 2012). Ratings are established for the three categories of performance including safety, repair cost and functional recovery time. The results showed that both buildings achieve ratings of five and two stars for the safety and recovery dimensions respectively. However, for damage dimension, 2A gets a four stars rating while 2B has a five stars rating. At the design basis earthquake (DBE) level, the mean repair cost normalized by the building replacement value is 5.57% for the code-based building and 4.01% for the LATBSDC building. However, at the MCE level, the repair costs for the LATBSDC building (20%) is about 18% higher than that of the code-based building (17%). This result is explained by the fact that the residual drift demands are significantly higher in LATBSDC building and dominates the losses at the MCE level. For both buildings, the REDi recovery time is dominated by impeding factors which account for more than 75% of the functional recovery time.