Seismic fragility and risk assessment of self-centering wall structures with traditional and sliding joint infill walls

Self-centering (SC) precast wall structures have emerged as earthquake-resilient structural systems with excellent seismic performances characterized by low damage as well as negligible post-earthquake residual deformation. However, research on SC wall systems often ignores infill walls for simplicity, which results in difficulty to achieve an integrated resilient structural system. To fill this gap, this paper presents a comprehensive assessment of SC precast concrete wall structures with three different types of infill walls and compares the results with that without infill walls. The maximum inter-story drift, the peak floor acceleration, and the damage index of the considered systems at different seismic intensities are calculated through incremental dynamic analysis. The assessment is then expanded from fragility to risk by evaluating the probabilities of exceeding each potential limit state throughout the service life. Results show that, despite merely no damage to the SC wall itself, the integral system could sustain significant damage due to the damage to the infills attached. What's more, with stronger infill walls, severer damage to the integral system is likely to be. Among the three infills considered in this study, the one with sliding joints performs the best from the perspective of damage, resulting in a smaller likelihood of 21%similar to 60% exceeding various damage limits than that of traditional infills. However, the sliding joint infill's benefit in damage is at the expense of larger drift and slightly higher acceleration responses compared with traditional infills. It is concluded that the infills considered in this paper all have their drawbacks and new infills that combine the sliding mechanism (to reduce damage) and higher damping (to reduce drift and acceleration) are encouraged to develop an integrated resilient system.