Study on time-dependent seismic fragility analysis of RC frame structures corroded by the most disadvantageous chloride attack

Based on a one-dimensional Fick's second law and the probability prediction model of initial corrosion time in DuraCrete Code, the remaining reinforcement diameters were calculated by the Statistical formula. Considering the cracking and spalling in the compressed concrete of compression zone caused by reinforcement corrosion, the modified compression-field (MCF) was used to predict the peak value of compressive strength by the function of the single-factor time-dependent remaining reinforcement diameters. Concerning parameters of the material constitutive models of corroded reinforcement and Mander confine concrete were also modified by the remaining reinforcement diameters. At the same time, the time-dependent fragility model was developed for corroding reinforced concrete (RC) frame designed according to the Chinese Code with a merger between a probabilistic model for chloride-induced corrosion and fragility model for undamaged RC frames. Finally, with the forced-based fiber plastic hinge model, the software SeismoStruct was employed to build the numerical model of the three-floor plane frame. Based on the material degradation models presented above, the time-dependent fragility curves and surfaces of three-floor RC frame in four ages (i.e., non-corroded (t=0), 5, 10 and 15 years), corresponding to different performance levels, were depicted by the incremental dynamic analysis(IDA) method. This method may be employed to predict service-life and life-cycle cost analysis of RC frame structures ©, 2015, Chinese Vibration Engineering Society. All right reserved.