Keywords: seismic sidesway collapse; simplified analysis; nonlinear static (pushover); incremental dynamic analysis (IDA); collapse margin ratio (CMR); FEMA P695; soft story; high performance computing; viscous dampers; hysteretic dampers.
Abstract: A simplified procedure is developed for estimating the seismic sidesway collapse capacity of frame building structures. The procedure is then extended to quantify the seismic collapse capacity of buildings incorporating supplemental damping systems. The proposed procedure is based on a robust database of seismic peak displacement responses of viscously damped nonlinear single-degree-of-freedom systems for various seismic intensities and uses nonlinear static (pushover) analysis without the need for nonlinear time history dynamic analysis. The proposed procedure is assessed by comparing its collapse capacity predictions on 1,470 different building models with those obtained from incremental nonlinear dynamic analyses. A straightforward unifying collapse capacity based design procedure aimed at achieving a predetermined probability of collapse under maximum considered earthquake event is also introduced for structures equipped with viscous dampers (linear and nonlinear) and hysteretic dampers. The proposed simplified procedure offers a simple, yet efficient, computational/analytical tool that is capable of predicting collapse capacities with acceptable accuracy for a wide variety of frame building structures incorporating several types of supplemental damping systems.