An Analytical Comparison of Seismic Design Provisions of is 1893:2016 and is 1893:2025 and its Implications on Reinforced Concrete Building Design

Seismic design codes play a critical role in minimizing structural damage during earthquakes by providing rational procedures for estimating seismic forces. In India, IS 1893 serves as the principal standard for earthquake-resistant design and has recently been revised as IS 1893:2025 to reflect advancements in seismic hazard assessment and design philosophy. The revised code introduces modifications in seismic zoning parameters and response spectrum formulation, particularly influencing structures with longer natural periods. This study presents a manual analytical comparison between the seismic force provisions of IS 1893:2016 and IS 1893:2025 for a tall reinforced concrete moment-resisting frame building. The equivalent static method is adopted to compute design seismic forces without the use of numerical analysis software. Key parameters such as natural period, spectral acceleration, design horizontal seismic coefficient, base shear, and storey-wise force distribution are evaluated and compared. The results indicate an increase in seismic demand under IS 1893:2025, highlighting the impact of revised long-period spectral characteristics. The study provides practical insight into the implications of the updated code provisions for seismic design practice in India.