Lateral Load Response of Pre-Engineered Buildings with Conventional and Advanced Bracing Systems

Pre-Engineered Buildings (PEBs) are widely used in industrial and commercial construction because of their structural efficiency, faster erection, and economic advantages. However, due to their large spans, lightweight steel sections, and relatively flexible framing systems, PEBs are highly vulnerable to lateral loads such as wind and earthquake forces. Hence, the selection of an appropriate bracing system becomes essential to improve stiffness, stability, and overall seismic performance. The present study presents a comparative assessment of a steel PEB structure incorporating five different bracing configurations: Conventional X-bracing, Harp bracing, and Perimetral bracing. The structure is modelled and analysed using ETABS software in accordance with IS 800:2007 for steel design, IS 875 (Parts 1, 2 and 3):2015 for gravity and wind loads, and IS 1893 (Part 1):2020 for seismic analysis. Wind and earthquake loads are considered, and seismic effects are evaluated using the Response Spectrum Method. The investigation focuses exclusively on the distribution of translational (UX, UY) and rotational (RX, RY, RZ) mass participation across vibration modes for Conventional X bracing, Harp bracing, and Perimetral bracing systems. The results indicate significant variation in modal mass distribution depending on the bracing configuration. The Conventional X bracing system exhibits mass participation distributed over multiple modes in the longitudinal direction, along with noticeable torsional coupling, indicating the influence of higher modes on seismic response. Harp bracing demonstrates improved dynamic efficiency by concentrating mass participation within fewer lower-order modes, thereby reducing higher-mode dominance and torsional irregularities. The Perimetral bracing system shows the most desirable behaviour, with nearly complete mass participation captured in the fundamental modes of both principal directions, ensuring predictable and stable seismic response. The findings confirm that advanced bracing systems enhance dynamic performance by minimizing higher-mode effects and controlling torsional response, thereby improving the overall seismic reliability of PEB structures