Reliability-based evaluation of seismic design and performance of steel self-centering moment-resisting frames

Recently developed steel self-centering moment-resisting frames (SC-MRFs) have been analytically and experimentally validated as having the potential to eliminate structural damage under a design basis earthquake and restore their original vertical position following a major earthquake. Three, nine, and twenty story prototype buildings were designed according to the existing performance-based design procedure for SC-MRFs. Using Monte Carlo simulation, nonlinear models of the prototype SC-MRFs were subjected to thousands of natural and synthetically generated ground motions. Peak structural demand responses such as story drift and beam-column relative rotation were recorded. This data was used to examine the sensitivity of the SC-MRF behavior to structural properties and geometry, seeking to refine the recommendations in the existing design procedure. A reliability-based methodology was used to assess the likelihood of reaching a key limit state of post-tensioned strand yielding.;This research develops the understanding of behavior and performance of steel SC-MRF systems. It (1) expands the current knowledge of the seismic response data for these systems, (2) quantifies their structural performance in terms of probabilistic predictions of the seismic hazard, and (3) validates and refines the existing seismic design recommendations for this system. Quantified likelihood of reaching a limit state in the system can be used to explore the ways to optimize the design by balancing the appropriate level of seismic safety with the life-cycle cost efficiency.;Self-centering frames are a viable alternative to the conventionally designed steel moment-resisting frames, as they exhibit equivalent stiffness and strength, and can eliminate the excessive residual drifts associated with the conventional frames. By using a reliability-based methodology (for the first time) to validate the existing seismic design procedure for SC-MRFs, this dissertation contributes to the ongoing research needed to develop the guidelines to be included in the design standards used by practicing engineers.;Further, this research advances the state-of-the art for designing resilient buildings to resist earthquakes. The current design practice ensures that the basic life safety objectives of structural design are met, however the post-earthquake damage related to such level of structural performance can be costly and require time until a fully functional state of a building (and its occupants) is restored. The analysis of SC-MRFs shows that even after a major earthquake, minimum, if any, repairs to the structure are needed. These frames are therefore an example of a new vision and goal for damage-free seismic design of structures.