Resilience-incorporated seismic risk assessment of precast concrete frames with “dry” connections

A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame (PCF) structures with “dry” connections in terms of their low damage and rapid recovery. The framework integrates various uncertainties in the seismic hazard, fragility, capacity, demand, loss functions, and post-earthquake recovery. In this study, the PCF structures are distinguished from ordinary reinforced concrete frame (RCF) structures by characterizing multiple limit states for the PCF based on its unique damage mechanisms. Accordingly, probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit states. In the seismic resilience analysis, a step-wise recovery model is proposed to idealize the functionality recovery process, with separate considerations of the repair and non-repair events. The recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss estimation. As such, contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely circumvented. The proposed framework is demonstrated through a comparative study between two “dry” connected PCFs and one RCF designed as alternative structural systems for a prototype building. The results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the RCF. Particularly, the PCF equipped with energy dissipation devices at the “dry” connections largely reduces the expected economic loss, downtime, and resilience loss by 29%, 56%, and 60%, respectively, compared to the RCF.