Jilugu Bhanu Prakash
Wind-induced lateral forces generated by tropical cyclones are among the most critical design considerations for multi-storey reinforced concrete buildings situated in coastal and high-wind zones. When subjected to extreme cyclonic aerodynamic pressures, conventional moment-resisting frames designed primarily for gravity loads exhibit excessive inter-storey drift, elevated bending moments, amplified support shears, and an increased risk of progressive structural failure. This study presents a systematic, quantitative comparison of nine structural configurations for a symmetric G+10 reinforced concrete building (plan 20 m x 20 m; height 35.2 m) subjected to cyclonic wind loading. The configurations comprise a bare conventional frame (baseline), two reinforced concrete shear wall arrangements (corner and central bays, 150 mm thick), and six steel bracing schemes - single diagonal, double diagonal (X), and K-bracing, each at corner and middle bay positions using ISA 100 x 100 x 12 mm angle sections. All nine models were developed and analysed using STAAD.Pro finite element software, with wind loads computed in strict accordance with IS 875 (Part 3): 2015 for Wind Zone V (basic wind speed 50 m/s). Structural response was evaluated through three indicators: maximum lateral nodal displacement in the principal wind direction, base shear reaction at the foundation, and maximum bending moment in the frame members. The bare conventional frame recorded the largest displacement (88.452 mm), exceeding the serviceability drift limit of H/500 = 70.4 mm. The centrally placed shear wall produced the lowest displacement (24.097 mm) but the highest base shear (763.586 kN). Among the bracing systems, double (X) bracing at the middle bays produced the most balanced response, with a displacement of 33.633 mm, a base shear of 201.073 kN, and the lowest bending moment of all nine configurations at 44.148 kN-m. The study concludes that double bracing positioned in middle bays offers the most structurally efficient and practically constructible lateral load-resisting strategy among the steel bracing systems evaluated, and recommends it as the preferred system for the cyclone-resistant design of the G+10 building considered.