Evaluation of seismic performance of unbonded post-tensioned precast concrete walls with internal and external dampers. II: Design criteria and numerical research

This paper presents an analytical procedure to assess the monotonic (envelope) force-deformation response (capacity curve) of unbonded post-tensioning precast concrete (UPT) walls with internal and external replaceable dampers. This procedure, which can also be used to design UPT walls, was compared and validated against experimental evidence. A close agreement (strength discrepancies of 2% on average) was found between the response predictions and experimental results. This agreement was maintained until peak strength was achieved. Moreover, fiber-based models were implemented to further study the cyclic behavior of UPT walls designed according to the proposed analytical procedure. The numerical models were accurate in representing the global cyclic behavior of UPT walls in terms of strength, displacement capacity, and energy dissipation; nonetheless, these models showed some discrepancies in capturing the residual drifts of some UPTwalls with internal dampers. A parametric analysis was also conducted to explore the influence of some design parameters on the deformation capacity and energy dissipation of UPTwalls. It was found that the ratio of damper reinforcement is critical for the energy dissipation and self-centering capacity of UPT walls, so ratios of 0.10 to 0.25 should be provided to follow the limit states indicated in this paper. Based on the results, the analytical procedure and limit states presented in this paper are considered suitable for UPT walls with external replaceable dampers under total axial load ratios equal or lower than 0.125. keywords: Post-tensioning; Precast concrete; Self-centering system; Shear walls; Nonlinear analysis; Finite element (FE) analysis; Fiber models; Seismic dampers.