Minimization Of Soft Storey Effects In Symmetrical Structure Using IS Code Method
Keywords:
Soft storey, Symmetrical structures, Seismic performance, IS 1893:2016, Inter-storey drift.Abstract
Soft storey configurations in multi-storey buildings significantly increase vulnerability to seismic forces, particularly in high-seismic zones across India. This empirical study investigates the effectiveness of Indian Standard (IS) code provisions in mitigating soft storey effects in symmetrical structures. The research employs dynamic analysis on various symmetrical building configurations with soft storeys at different levels, comparing their seismic performance before and after implementing IS code recommendations. Five structural models with varying soft storey positions were analyzed using response spectrum analysis under seismic conditions typical of Indian seismic zones III and IV. Results demonstrate that implementing IS 1893:2016 provisions for soft storey mitigation reduced inter-storey drift by 37-42% and decreased storey displacement by 28-33% compared to conventional designs. The study found that soft storeys at lower levels exhibited 1.8 times higher vulnerability than those at intermediate levels. Design modifications including enhanced column stiffness, strategic shear wall placement, and increased beam-column capacity ratio proved particularly effective, with combined implementation reducing the structural vulnerability index by 45.6%. These findings validate the effectiveness of IS code provisions while offering optimization strategies for symmetrical structures in India's seismic regions.
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