A Comparative Study on Seismic Performance of Irregular RCC Frames with Shear Wall and Bracings

Abstract

In the present study, seismic performance of Irregular RCC frames is investigated using ETABS software. Regular frame, type s1 vertical geometrical irregular frame, type s1 with shear wall and type s1 with bracings are considered and are modelled as per IS 1893–Part 1 (2002). Seismic parameters viz. storey displacement, storey shear, auto lateral loads for the developed RCC models are obtained by response spectrum analysis as per IS 1893–Part 1 (2002) in seismic zone V.

Introduction

I. INTRODUCTION

Earthquake is one of the most devastating of all the natural hazards and is considered to be the most powerful disaster which is unavoidable. IS 1893–Part 1 (2002) stipulates the criteria for earthquake resistant design of structures With the Increase in the modern architecture, different complex design of buildings has been introduced in the construction field. These architectural works sometimes create problem for the structural engineer regarding the structure’s stability and safety. In most of the cases it is the vertical irregularity of the building. Vertical irregularity in building refers to variations or deviations from a regular pattern in the vertical alignment or distribution of a building's structural components, such as columns, beams, walls, or floors. This paper demonstrates how a regular and vertical geometric irregular structure performs and behaves when subjected to seismic activity.

From Fig. 5 for the seismic zone V, it is observed that TYPE S1 model shows promising performance in terms of base reactions, while additional analysis and review may be needed for the TYPE S1 model with Shear Walls (SW) to understand the differences in behaviour compared to the other models.

From Fig. 6 for the seismic zone V, it is observed that all models (except shear wall model) achieved an outstanding 99% response reduction factor. This suggests that these models are designed with robust lateral load-resisting systems and effective energy dissipation mechanisms, making them highly resilient against seismic forces.

 From Figs. 7 and 8 for the seismic zone V, it is observed that the TYPE S1 model with Shear Walls (SW) is the best performing model, and the model with bracings is the second best. These findings indicate that the inclusion of shear walls and bracings significantly enhances the structure's seismic performance by reducing lateral displacements.

From Figs. 9 and 10 for the seismic zone V, it is observed that the TYPE S1 model is the best performer, and the model with bracings is the second best. These findings suggest that both the TYPE S1 model and the model with bracings effectively resist lateral forces in the X-direction. From Figs. 11 and 12 for the seismic zone V, it is observed that TYPE S1 model performs the best in terms of auto lateral loads in the Y-direction, and the model with bracings ranks as the second-best performer. Here's a summary of the auto lateral results in the Y-direction for each model, ranked from best to second best.

Conclusion

Based on the analysis and comparison of the results in terms of displacement, storey shear, and auto lateral load, the following conclusions can be drawn: 1) Performance of type s1 model: the type s1 model without any additional lateral load-resisting systems has demonstrated excellent seismic performance in all aspects, including displacement, storey shear, auto lateral loads, and response reduction factor. 2) Shear walls and bracings: The inclusion of shear walls and bracings in the structural models showed improvements in certain aspects of seismic performance. The models with shear walls and bracings had lower displacements and storey shears compared to the basic type s1 model. 3) Best performing model: Considering all results, the type s1 model without shear walls, bracings, or any additional lateral load-resisting systems stands out as the best performer. It demonstrated superior seismic resistance compared to other models, including those with shear walls and bracings. 4) Importance of proper design: The results highlight the critical role of a well-designed and balanced structural system in achieving optimal seismic performance. Careful consideration of lateral load-resisting systems, their configuration, and detailing is crucial to ensuring structural safety and resilience during seismic events. 5) Project-specific considerations: It\'s important to remember that every project is unique, and the selection of lateral load-resisting systems should be tailored to the specific building design, site conditions, and local seismic requirements. 6) Professional expertise: Engaging experienced structural engineers and seismic experts is vital to conduct a thorough analysis, interpret results accurately, and make informed decisions during the design process. 7) Continuous monitoring and maintenance: Even with a well-designed structure, ongoing monitoring and maintenance are essential to ensure long-term resilience against seismic hazards. In conclusion, based on the analysis results, the type s1 model without additional lateral load-resisting systems emerges as the optimal choice for the given project, demonstrating superior seismic performance across all evaluated criteria.

References

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Copyright

Copyright © 2023 Akshatha M, Chidananda G, Arpitha D J. 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.