Influential properties of hysteretic energy dissipating devices on collapse capacities of frames

• To obtain grounds for the 75-% criterion of the minimum seismic base shear carried by the seismic force-resisting system
• To obtain the rational grounds on the 75 % criterion related to the minimum seismic base shear carried by the seismic force-resisting systems
• To quantitatively evaluate the collapse capacities of damped structures based on the procedure of FEMA P695

Various advantages of hysteretic energy dissipating devices (HEDDs) have been recognized and their applications are getting popular. In parallel with this, current seismic codes prescribe a design procedure for structures employing HEDDs. According to one of seismic codes, ASCE/SEI 7, the minimum seismic base shear resisted by its seismic force-resisting systems (SFRSs) shall not be < 75% of the total seismic base shear which is carried by a structure. This minimum base shear requirement for SFRSs is implicitly intended to provide safety in the event of malfunction of HEDDs. Although there are rigorous requirements for damped structures, further studies are still required to investigation of the collapse capacities of damped structures which have increasingly paid attention to earthquake engineering communities. In order to address this, this study carried out incremental dynamic analyses to evaluate the collapse performance of the 3- and 6-story prototype steel special moment-resisting frames (SMRFs) with and without HEDDs of which the strength capacities are different. The analysis results show that the collapse margin ratios of the prototype frames depend on the amount of base shear carried by their HEDDs and uncertainties on design requirements. The prototype structures with larger seismic base shear carried by HEDDs result in small variation in collapse capacity distribution and satisfy the minimum collapse margin ratio regardless of uncertainties on design requirements.