Seismic risk assessment of mid-rise cold-formed steel structures in China considering various uncertainties

Seismic risk assessment is an important aspect for the performance-based seismic design of building structures. Cold-formed steel (CFS) structure is a typical green and industrialized building system, but very few investigations have been conducted on seismic risk assessment of CFS structures. This study aims at analyzing and assessing various uncertainties involved in seismic analysis of CFS structure, and then quantifies its seismic risks. A typical 6-story CFS building of eight-fortification is designed. Based on the simplified numerical analysis method verified by shaking table tests, a simplified numerical model of the building is established for quantifying various uncertainties and seismic risks. The results show that: because the shape parameters of seismic hazard function are large for some regions in China, the failure probability of CFS structure increases remarkably if various uncertainties are considered, and the collapse probability in 50 years of the building increases more than ten times; the case building basically meets the requirements that no damage under minor earthquake, no un-repaired damage under moderate earthquake, and no collapse under major earthquake proposed by the standard in China, but the probabilities on slight damages of the CFS buildings at some special regions should be controlled appropriately. Besides, various uncertainties shall be considered comprehensively for their effects on seismic risk quantification of CFS structures, and the values of uncertain parameters as well as the method of calculating the seismic risks proposed in this study can be referred to. © 2021, Editorial Office of China Civil Engineering Journal. All right reserved.