PARAMETRIC STUDY OF BRACED MEGA FRAMES CORE TUBE STRUCTURAL SYSTEM WITH DIFFERENT MATERIALS.

·       Composite and Structural Steel Braced Mega-Frame Core Tube systems exhibited superior seismic performance compared to RCC buildings for both G+30 and G+50 structures. The Composite system showed the best overall performance with higher lateral stiffness and lower displacement. ·       Plan irregularity significantly influenced seismic behaviour. L-shaped and T-shaped buildings showed higher storey displacement, storey drift, and torsional effects, whereas the Plus-shaped configuration performed better due to its balanced structural layout. These effects became more significant from G+30 to G+50. ·       With increasing building height, seismic response became more critical. However, Composite and Structural Steel systems reduced storey displacement by 8–61% in G+30 and up to 55% in G+50, while storey drift was reduced by 8–81% in G+30 and up to 63% in G+50, demonstrating better nonlinear seismic performance and energy dissipation. ·       Composite and Structural Steel systems also achieved a 6–35% reduction in the fundamental natural time period and higher storey stiffness. Although base shear increased by about 25% in G+30 and 6–24% in G+50, and base moments increased by more than 23% in several irregular G+50 models, these systems provided superior seismic performance and structural efficiency compared to conventional RCC buildings.

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