A Practical and Innovative Alternative Framework for Plastic Design of Structures

This paper challenges the efficiency of the collapse‐based design (CBD) method as an innovative framework for the plastic design of structures. It aims to evaluate this method as a suitable and efficient alternative to conventional seismic design principles by examining its speed, accuracy, and simplicity. In this study, a three‐dimensional buckling‐restrained braced frame (BRBF) with an irregular plan is selected as the prototype model and designed using the CBD method. Because this design approach relies solely on the load‐to‐capacity ratio of individual elements under the median collapse intensity of the model, it is essential to assess the structural behavior under various seismic intensities. This ensures that the method can effectively control both capacity and structural damage, maintaining satisfactory performance across different seismic hazard levels. To achieve this, the irregular 3D‐BRBF model is designed using CBD principles and then evaluated through nonlinear time history analysis (NTHA), incremental dynamic analysis (IDA), and pushover analysis. In addition, the ultimate capacity of the model is quantified according to the FEMA P695 methodology, and its fragility curves and residual displacements are investigated. The results demonstrate that the CBD method, with its simplified principles, accurately addresses the factors influencing seismic behavior and effectively controls structural damage. Moreover, the techniques employed can reduce the structural analysis time in each round of the design process by up to 450 times compared with both IDA and NTHA, while retaining the benefits of these analyses and applying them in design, thus simplifying the design principles to their most basic form. The CBD‐designed structure meets the minimum requirements of seismic codes and standards. Furthermore, evaluations indicate that this framework operates quickly, simply, and accurately, effectively meeting seismic design needs. Consequently, the CBD method is proposed as a suitable and efficient alternative framework for the plastic design of structures.