Steel Bracing and Fundamental Periods in RC Buildings: A Computational Analysis

Abstract

Understanding the seismic performance of Reinforced Concrete (RC) buildings is crucial for ensuring structural safety in earthquake-prone regions. This study examines the impact of different types of steel Concentrically Braced Frames (CBF) on the fundamental periods of RC buildings, following the BNBC 2020 guidelines. Utilizing ETABS 2021 for computational modeling, the research comprehensively analyzes RC buildings' dynamic behavior with diagonal (D-bracing), cross (X-bracing), and inverted V-bracing systems. Key structural parameters were evaluated to understand their influence on the fundamental periods, including total height, building length, building width, bracing moments of inertia, and total length of bracing. The study revealed that the BNBC 2020 guidelines, which use a general formula for predicting fundamental periods, do not accurately capture the dynamics of buildings with specific bracing configurations, with R² values of 0.65576 for D-bracing, 0.62273 for X-bracing and 0.64396 for inverted V-bracing. To address this limitation, new predictive equations were developed using linear regression in OriginLab, achieving substantially higher R² values of 0.96433 for D-bracing, 0.94696 for X-bracing, and 0.95757 for inverted V-bracing. These results demonstrate the superior accuracy of the proposed equations. The findings underscore the critical role of bracing types in enhancing the seismic performance of RC buildings. By providing tailored predictive models, this study offers valuable tools for engineers and designers, contributing to more accurate and reliable seismic design practices. The proposed equations enable the optimization of RC building designs for improved safety and resilience in seismic regions, thereby advancing the field of structural engineering.