Quantitative seismic resilience evaluation of steel braced frames retrofitted using buckling-restrained braces

Ahmed A. Saeed , Sherif A. Mourad , Omar A. Sediek

Abstract

Earthquakes have historically caused significant impacts on human societies and the built environment, emphasizing the need for proactive disaster preparedness. Seismic retrofitting is a key strategy for enhancing structural resilience, particularly for existing buildings that do not meet modern seismic standards. This study examines the effectiveness of retrofitting steel ordinary braced frames (OBFs) with buckling-restrained braces (BRBs). Three prototype OBF buildings of varying heights (4, 6, and 10-story) are designed according to an outdated code and retrofitted by replacing conventional braces with BRBs. A detailed finite element (FE) model is developed and validated against experimental data, then used to conduct a comprehensive seismic resilience assessment, including fragility analysis and loss estimation in terms of repair cost, repair time, and debris generation. Incremental dynamic analysis (IDA) is performed on unretrofitted and retrofitted buildings using eleven scaled ground motions, with simulations carried out up to collapse. Fragility curves quantify improvements in peak ground acceleration and base shear due to BRB retrofitting. Results show that BRBs substantially enhance resilience, reducing interstory drifts by 45%, repair cost by 47%, repair time by 44%, and debris by 57%. These findings confirm the effectiveness of BRBs, especially for low- and mid-rise buildings in seismically active regions.

Key Words

buckling restrained braces; finite element; risk assessment; seismic resilience; seismic retrofit

Address

Ahmed A. Saeed — Department of Structural Engineering, Cairo University, Giza 12613, Egypt
Sherif A. Mourad — Department of Structural Engineering, Cairo University, Giza 12613, Egypt
Omar A. Sediek — Department of Structural Engineering, Cairo University, Giza 12613, Egypt

PDF Viewer

Preview is limited to the first 3 pages. Sign in to access the full PDF.

← Back to Volume 59, No. 5