Seismic collapse assessment of a 20-story steel moment-resisting frame structure

Abstract

The 2010 edition of the load standard in the United States (U.S.), ASCE 7-10, (Minimum Design Loads for Buildings and Other Structures) introduced risk-targeted spectral acceleration values for the estimation of seismic design loads. In this study, a 20-story steel moment resisting frame structure located in Century City, CA, USA was designed based on ASCE 7-10 and a probabilistic seismic collapse assessment was conducted. The main goals of this study are: (a) to evaluate whether the design of a typical steel moment-frame structure based on risk-targeted spectral accelerations fulfills the target design collapse level of 1% probability of collapse in 50 years; and (b) to quantify the collapse potential of a tall steel structure design based on the most current U.S. seismic code provisions. The probability of collapse was estimated for two sets of 104 and 224 recorded ground motions, respectively. An evaluation of the results demonstrated that for this specific structure the code-prescribed collapse performance target was reasonably met.