Evaluation of the seismic collapse capacity of steel moment-resisting frames designed using Elastic Design (ED) and Performance-Based Plastic Design (PBPD) methodologies

• Published in: I-Manager's Journal on Civil Engineering Vol. 15; no. 1; p. 1
• Main Authors: Kourosh, Mehdizadeh, Abbasali, Sadeghi, Amirreza, Sadeghi, Mohammad, Hossein Razmkhah
• Format: Journal Article
• Language: English
• Published: Nagercoil iManager Publications 01.03.2025
• Subjects: Buildings; Collapse; Design; Earthquake damage; Fragility; Plastic design; Seismic activity; Shear forces; Statistical analysis; Steel frames; Structural failure
• ISSN: 2231-1068; 2249-0779
• DOI: 10.26634/jce.15.1.21742

In the past, calculating and spreading seismic base shear forces along the height of buildings mainly used the elastic design (ED) method found in different structural codes. This approach often resulted in designs that were neither optimal nor cost-effective, potentially leading to severe damage to buildings during seismic events. To address these shortcomings, the Performance-Based Plastic Design (PBPD) method has emerged in recent years, emphasizing the plastic behavior of structures. This study focuses on assessing the seismic collapse capacity of Steel Moment Resisting Frames (SMRFs) designed using both the ED and PBPD methods. Two SMRFs, comprising five and ten stories with intermediate ductility, were analyzed using OpenSees software and subjected to seven pairs of far-fault earthquake records. Subsequently, incremental dynamic analysis (IDA) was conducted until structural failure occurred, allowing for the extraction of fragility curves to evaluate the seismic collapse capacities of the frames. The results show that the PBPD method improves how well we can manage the ways structures bend and change shape under stress. Furthermore, the probability of failure for frames designed with the PBPD method is deemed acceptable. Notably, the research reveals that the seismic collapse capacities of frames designed with PBPD are significantly superior to those designed with ED, with a 25% and 31% increase in collapse capacity for the five-story and ten-story frames, respectively, at a statistical level of 50%. This result underscores the reliability and precision of the PBPD method in comparison to the ED approach.