Modified performance-based plastic design for self-centering structures

The Performance-Based Plastic Design method (PBPD), developed on the energy concept, has been frequently used in technical literature as a performance-based design method for various structures. However, implementing the method for self-centering (SC) structures, which can concentrate damage in replaceable members and reduce residual deformation, encounters difficulties due to selecting an overall energy modification factor regardless of structural geometry, ductility, and energy absorption capacity. In this study, considering the behavior of self-centering structures, the PBPD method is modified to implement any SC structure with a specific energy modification factor. The proposed method was then implemented to design two braced SC structures with different height, cable, and damper configurations. For comparison, the designed structures and similar structures designed by force method under identical conditions were subjected to nonlinear dynamic and pushover analysis employing eleven far-field earthquake records. The results show that the structures designed by the energy method with different heights and configurations exhibit average seismic response close to the target performance response while maintaining cable linearity. While in the force method, the cables did not remain linear in some cases, and the structures were designed with about 20 % deviation of mean response to the target performance. Furthermore, assessing the proposed approach with analytical results in terms of absorbed energy reveals that the accuracy of the proposed method in forecasting the structures' input energy was more than 87 %. The results indicated that the modified energy method is simple, accurate, straightforward, and efficient for the PBPD of SC structures.