Structural Behaviour of Friction Dampers and Isolation Techniques for Seismic Vibration Control of Buildings

Abstract

Buildings often provide individuals’ shade. Construction of large structures is necessary because most people prefer solitude. Tall buildings have the drawback of being less earthquake-resistant. Therefore, tall buildings constructed in seismically active areas may sustain serious damage or even die. Therefore, a building\'s construction must be capable of withstanding the lateral and gravitational forces generated by earthquakes. Multi-story buildings employ a specific method to withstand lateral loads. The storey\'s RC-framed construction used three distinct bracing methods. We have examined and assessed the G+14 stored RC frame design for seismic zone IV. We use computer-aided software, STAAD Pro V8i, to analyse the RC-framed models using the Response Spectrum Method. We examined the structural behaviour using a range of bracing methods, including X-bracing, inverted-V bracing, and V-bracing. We placed these techniques at different positions on the outer faces and all four sides of the constructions. We examine the parameters of time, base shear, storey drift, storey displacement, bending moment, and peak storey shear for both braced and unbraced models. The braced frame\'s base shear value increases compared to an unbraced frame, while its storey displacement, storey drift, bending moment, and duration decrease. The braced frames have higher peak story shear values. The model with X-bracing on the mid-bays of the buildings\' exterior sides significantly increases the structure\'s stiffness when compared to the alternative bracing technique.

Introduction

• Earthquakes are caused by natural (e.g., geological faults) and human-made activities (e.g., mining), generating seismic waves that apply lateral forces to structures.

• In India, many structures are inadequately engineered, especially in seismic zones III, IV, and V.

• Seismic resistance isn't just about strength, but also about controlling displacement within safe limits.

• Multi-story RC buildings are especially vulnerable to deformation.

• Steel bracing systems (like X, V, and Inverted-V) are introduced to improve lateral stiffness and reduce deformation.

2. Objectives of the Study

• Use STAAD.Pro V8i software for modeling and seismic analysis.

• Perform Response Spectrum Analysis on RC frames with Concentric Braced Frames (CBF).

• Compare seismic parameters: storey drift, displacement, time period, bending moment, storey shear, and base shear.

• Identify the most effective bracing configuration for seismic zone IV in RC buildings.

3. Structural Model Details

• Structure: G+14 RC-framed building (15 storeys)

• Plan dimensions: 12 m x 12 m (square)

• Floor height: 3 m per storey

• Beam: 450 x 450 mm | Column: 600 x 600 mm

• Bracing: ISMB200 steel sections

• Loads: Dead Load – 3 kN/m² | Live Load – 4 kN/m²

• Seismic Zone: IV

• Soil Type: Medium

• Importance Factor (I): 1.0

• Response Reduction Factor (R): 5

• Support Type: Fixed

• Damping Ratio: 5%

• Analysis Method: Response Spectrum (linear dynamic analysis)

4. Bracing Systems Analyzed

• X-Bracing

• V-Bracing

• Inverted V-Bracing

• Placement of bracing in different bays and storeys was analyzed.

5. Key Findings from Seismic Analysis

A. Time Period

• Braced frames show a significant reduction in time period compared to bare frames.

• X-bracing in middle bays (Model 2) reduces time period by 19.24%.

• Lower time period = higher stiffness and better resistance to dynamic forces.

B. Base Shear

• Base shear is the maximum horizontal force at the base.

• Bracing increases base shear slightly, indicating better energy dissipation.

• Values are relatively consistent across different bracing configurations.

C. Storey Displacement

• Displacement is lowest in X-bracing, especially when placed in middle bays.

• X-bracing effectively reduces lateral movement at critical floor heights (24m, 42m).

D. Storey Drift

• Storey drift is greatly reduced in braced models, particularly between storeys 3 to 7.

• X-bracing shows the steepest decline in storey drift values.

• Indicates enhanced inter-storey stiffness and reduced risk of collapse.

E. Bending Moment

• Braced models significantly reduce bending moment in beams/columns.

• X-bracing again proves most effective, reducing bending moment by nearly 25% compared to bare frames.

Conclusion

1) The time period measures a building\'s response to an earthquake, with longer time periods indicating higher responses and shorter time periods indicating smaller responses. Model-2 has a shorter time period (1.125 seconds), making it more rigid and the most efficient among the models. In comparison, the unbraced structure has a longer time period (1.393 seconds). Model-2\'s time period is reduced by 19.24% compared to the bare frame (Model-1). 2) As the building height increases, the bracing system\'s lateral displacement diminishes in comparison to the bare frame. The structural model-2 shows less lateral displacement than the other bracing (inverted-V bracing and V-bracing) and un braced structures in zone IV. In zone IV, the reduction in lateral displacement values for model-2 at storey heights of 24 and 45 meters is 35.98% and 32.29%, respectively. 3) Models 2 and 3 have high base shear values compared to other models, according to the overall base shear correlation. The braced models\' base shear is higher than that of the un braced RC frame model. 4) The model minimizes storey drift by utilizing a variety of bracing techniques. A structural model with X-bracing on the outside of the building and on the middle bays (model-2) exhibits less floor drift than the braced and un braced structures. When compared to bare frame at storey heights of 24 and 45 meters, the model-2\'s storey drift values are reduced by 42.41% and 13.17%, respectively. 5) Bending moment values for the central column in the braced frame are lower than those in the un braced frame. The braced model with the X-bracing in the mid-bays has the lowest potential bending moment when compared to the other versions. Consequently, the X-bracing in the middle two bays of the construction is more effective. 6) At different structural levels, peak storey shear values increased in the braced frame model relative to the un braced frame model. The frame model-2 yielded better results because it could sustain more shear than the other models. It is minimum at the top of the building and maximum at the bottom. Thus, in terms of advantages, Model 2 is better than previous models.

References

[1] Katte, Aniket, and D. B. Kulkarni. \"Seismic Analysis of Multi-Storey Steel Structure with Steel Bracing at Different Location.\" International Research Journal of Engineering and Technology (IRJET), ISSN (2019):2395-0056. [2] AnesBabu, Dr,etal.\"Effect of steel bracings on RC framed structure.\"International Journal of Mechanics and Solids 9.1(2017):97-112. [3] Bajoria et.al. (2012) examined the steel structure with or without bracing for the seismic analysis. [4] Tupe, Rashmi,etal.\"Zinc inhibits glycation induced structural, functional modifications in albumin and protects erythrocytes from glycated albumin toxicity.\" International journal of biological macromolecules 79 (2015):601-610. [5] Chadhar and Sharma (2015) studied that for resisting the horizontal forces in RCC building. [6] Yadav, Purnima, Diptendu Roy, and Megha Kalra. \"Model-based analysis of base isolation systems for multistory buildings subject to various Seismic Events.\" (2018):209-221.

Copyright

Copyright © 2025 Kalyankar Anuragheswar , Dr. Ankit . 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.