uncertainty quantification in seismic collapse assessment of the iranian code-conforming rc buildings

Structural collapse is the main concern for the existing structures which are built in the seismic-prone regions. therefore, the primary goal of the seismic provisions in building codes is to prevent the global collapse. iran is located in the alpine-himalayan belt, and has experienced some of the most destructive earthquakes in the past century. to evaluate the extent to which the iranian building code provisions meet the abovementioned objective, the authors conducted a detailed assessment of collapse risk on a set of moderate moment resisting reinforced concrete (rc) buildings. while many features might affect the seismic performance of the rc structures, this study considers p-δ effects, deterioration in strength and stifiness, and cyclic deterioration in structural components. structural assessment was performed using opensees platform and the multiple-record incremental dynamic analysis (ida). results were obtained in terms of ida capacity curves and collapse fragility functions at different seismic hazard levels. results showed that probability of instability increased with height of the buildings. moreover, the collapse confidence level was evaluated considering the available uncertainties. assuming a minimum confidence level of 90% for the buildings, the collapse prevention (cp) limit state (ls) under the 2%/50 yr hazard level was not satisfied for the 9- and 12-story frames, and they needed to be re-designed.