Seismic Response Analysis of G+10 Storey Building in Zone IV Using Different Grade of Steel

Abstract

Seismic safety of reinforced concrete buildings remains a critical concern in earthquake-prone regions, particularly with the rapid increase in medium-rise urban construction. Traditional strength-based design approaches often fail to capture the complex dynamic behaviour of multi-storey structures subjected to earthquake loading, thereby necessitating performance-oriented analytical evaluation frameworks. This research paper presents a comprehensive seismic response assessment of a G+10 reinforced concrete building using advanced computational modelling in ETABS software. The study investigates the influence of different grades of reinforcing steel on key seismic performance indicators including storey displacement, inter-storey drift, base shear response, modal time period characteristics, and overall structural stiffness distribution. A controlled analytical methodology was adopted in which identical geometric configuration, loading conditions, and boundary assumptions were maintained while varying reinforcement grade parameters. Response spectrum analysis was performed in accordance with seismic design provisions applicable to Zone IV conditions to simulate realistic earthquake excitation effects. Comparative results demonstrate that higher grade reinforcement contributes to improved deformation control and reduced drift demand while influencing internal force distribution and dynamic response behaviour. The findings highlight the importance of material selection in achieving optimal seismic performance and provide valuable insights for performance-based design of medium-rise reinforced concrete buildings subjected to strong ground motion.

Introduction

Earthquakes pose a major threat to reinforced concrete (RC) buildings, especially medium-rise structures like G+10 buildings that are widely used in urban areas. Their seismic performance is influenced by complex factors such as material properties, stiffness, mass distribution, and dynamic behavior. Since reinforced steel grade significantly affects strength and stiffness, this study investigates how different reinforcement grades impact seismic response using ETABS-based response spectrum analysis for a building in Seismic Zone IV.

The literature shows a shift from traditional strength-based seismic design to performance-based approaches that emphasize displacement, drift, ductility, and energy dissipation. While modern computational tools and design codes have improved analysis accuracy, a research gap remains in systematically evaluating the effect of reinforcement grade under controlled conditions.

The study uses a G+10 RC building model with identical geometry while varying steel grades. Key performance parameters include storey displacement, inter-storey drift, base shear, and modal time period. Results show that higher-grade reinforcement reduces displacement and drift, improving stiffness and serviceability. However, it slightly increases base shear due to greater rigidity. Modal analysis indicates reduced time periods, confirming increased stiffness.

Conclusion

This research paper presented a comprehensive analytical investigation into the seismic performance of a G+10 reinforced concrete building considering the influence of different grades of reinforcing steel under response spectrum loading conditions corresponding to Seismic Zone IV. The primary objective of the study was to evaluate how variations in reinforcement material properties affect key structural response parameters such as storey displacement, inter-storey drift, base shear demand, and modal time period characteristics. By adopting a controlled computational modelling framework in which geometric configuration, loading conditions, and boundary assumptions were maintained constant, the research successfully isolated the role of reinforcement grade in governing dynamic structural behaviour. The analytical results demonstrate that higher grade reinforcement contributes significantly to improved deformation control in medium-rise reinforced concrete buildings. Reduction in global storey displacement and inter-storey drift values indicates enhanced lateral stiffness and increased resistance to earthquake-induced deformation. Such improvements are particularly important in seismic performance evaluation because excessive deformation is closely associated with both structural damage and non-structural component failure. The observed drift reduction suggests that reinforcement optimization can play an effective role in achieving performance objectives such as life safety and operational continuity following moderate seismic events. At the same time, the study highlights the fundamental trade-off between stiffness enhancement and seismic force demand. Increased structural rigidity associated with higher grade reinforcement results in marginally higher base shear values, reflecting greater inertia force attraction. This behaviour reinforces the importance of adopting balanced design strategies that integrate strength, stiffness, and ductility considerations rather than focusing exclusively on deformation control. Adequate detailing and capacity design provisions remain essential to ensure that increased force demand does not lead to premature failure mechanisms. Modal analysis results further confirm that reinforcement grade influences dynamic characteristics by reducing the fundamental natural time period of the structure. This change modifies resonance interaction with ground motion frequency content and contributes to overall variation in seismic demand distribution. Accurate representation of such material-dependent dynamic properties is therefore critical in computational structural analysis. The study demonstrates that advanced modelling tools such as ETABS provide valuable capabilities for evaluating parameter sensitivity and supporting performance-based design decisions. From a practical engineering perspective, the findings of this research provide useful guidance for material selection in medium-rise building construction located in high seismic hazard regions. Reinforcement grade optimization can improve structural resilience, reduce damage potential, and enhance long-term serviceability performance. However, designers must ensure that stiffness enhancement is accompanied by sufficient ductility capacity and energy dissipation mechanisms to maintain overall seismic safety. The research therefore contributes to the broader objective of developing rational, performance-oriented structural design approaches that balance safety, economy, and constructability considerations. Despite its contributions, the study acknowledges certain limitations that offer opportunities for future research. The analytical framework focused on a regular G+10 building configuration and response spectrum analysis methodology. Future investigations may extend this work by examining taller buildings, structural irregularities, soil–structure interaction effects, and nonlinear time-history analysis for more detailed performance evaluation. Experimental validation of analytical findings and integration of seismic retrofitting strategies such as bracing systems or supplemental damping devices may further enhance the reliability and applicability of results. In conclusion, the research demonstrates that reinforcement grade selection is a critical parameter influencing seismic performance of reinforced concrete buildings. Through systematic computational analysis and comparative response assessment, the study provides meaningful insights that support performance-based structural design and contribute to improving earthquake resilience in urban built environments.

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Copyright

Copyright © 2026 Bharti Lilhare, Dr. Bikram Prasad. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.