Study and Behaviour of Wind Evaluation of Multi-Storey Building with Floating Columns

Abstract

Tall buildings often face space constraints due to the current surge in urbanization. The structure can be affected by wind gusts in both directions. These gusts have the potential to impact the structure from both directions. Over the past few years, the structure has experienced effects from these gusts in both directions. These designs aim to enhance the visual perspective of the projects they undertake. The variability in floor height causes a discontinuity in the stiffness of the structure at the level of the soft story. This phenomenon is caused by floor height fluctuations. In the even If winds expose this discontinuity, it could potentially cause buildings to This study aimed to perform a static analysis of three-dimensional building frames, which included G+7 storeys, floating columns, and soft storey elements. elements. The other sixty-four examples feature floating columns at a single level, with the soft storey varying directly from the ground (G) story to the G+7 storey. Eight of the instances include centre floating columns on any one of the storeys, while sixty-four of the other cases have floating columns at a certain level. This instance considers a total of seventy-three instances. Furthermore, we construct a simple example where neither the storeys nor any of the column’s float, adhering to the previously stated conditions. We conducted the analysis using the maximum node displacements (resultant), maximum moments, maximum shear force, maximum axial force, and maximum storey drift. It is necessary to do an analysis of the findings in order to arrive at technical conclusions.

Introduction

• The key factor distinguishing high-rise from low- and mid-rise building design is the lateral loading caused by wind and earthquakes.

• Wind loads have minimal impact on buildings up to about 10 stories but increase significantly for taller buildings, causing larger deflections and structural demands.

• High-rise buildings tend to be lighter and more flexible, making them susceptible to wind-induced movements like wobbling.

2. Objectives

• Analyze building frames with floating columns and soft storeys under wind loads using STAAD.Pro software.

• Determine which structural configurations are more secure by studying:

  • Maximum node displacements

  • Maximum moments

  • Maximum shear forces

  • Maximum axial forces

  • Maximum story drift

3. Scope

• Focus on a G+20 story building model with and without floating columns, studied under seismic Zone III.

• Use Construction Sequence Analysis (CSA) combined with seismic load analysis.

• Examine responses such as storey drift, displacement, and storey shear.

• Floating column structures exhibit more movement than conventional column structures.

• Displacement generally increases from lower to higher stories.

4. Key Concepts

• Floating Column: A vertical column supported by a beam instead of directly extending to the foundation, disrupting direct load paths.

• Soft Storey: A story with significantly lower stiffness/resistance compared to adjacent floors, making it prone to higher lateral displacements.

• Both floating columns and soft storeys influence building performance under lateral loads, often negatively.

5. Literature Review Highlights

• Wind load effects increase with terrain slope and building interference.

• Composite structures tend to be lighter, more economical, and show acceptable displacement under wind and seismic loads compared to pure steel or concrete buildings.

6. Methodology

• Buildings categorized into three groups:

  1. Normal buildings (no floating columns or soft storeys)

  2. Buildings with floating columns only

  3. Buildings with floating columns plus varying soft storey locations

• Wind load calculations consider peak gust velocity and factors like terrain, risk, and topography.

• Structural models created and analyzed in STAAD.Pro with consistent plan dimensions.

7. Results and Discussion

• Wind pressure effects increase with building height and structural configuration.

• Column placement significantly affects structural response.

• Floating columns cause notable changes in structural robustness and performance.

• Displacement and drift increase with height, especially in buildings with floating columns and soft storeys.

• Recommendations include further research on buckling and wind load variations.

Key Takeaway:

Floating columns and soft storeys affect the wind resistance and seismic behavior of high-rise buildings, often increasing lateral displacements and reducing structural robustness. Careful design and analysis using advanced tools like STAAD.Pro are essential for ensuring safety and performance.

Conclusion

1) The analysis emphasizes the importance of considering wind loads when designing high-rise G+7 buildings with and without floating columns. The use of advanced modeling techniques aids in better understanding and mitigating potential risks . 2) When floating columns are present at the highest level of a building that contains non- soft floors, the structures produce the greatest nodal displacement. This is because floating columns give the building a more rigid appearance. 3) The floating columns are the ones responsible for the most nodal displacement, which explains why this is the case.Wind loads exert an influence, leading to a concentration of larger drift values up to the G+7 story level. This is due to the impact that wind loads have on the structure. 4) Providing good floor space index but risky & vulnerability of the building increases. 5) We can conclude that wind loads have the greatest potential to cause storey drift based on the assumption that floating columns and soft storey are both located at the G+2 storey level. 6) Wind loads exert an influence, leading to a concentration of larger drift values up to the G+4 story level. This is due to the impact that wind loads have on the structure

References

[1] Aakash Saxena and S.S. Kushwaha, “Seismic Evaluation of G+2 Institutional Building in Bhopal”, International Journal of Latest Research in Engineering and Technology, Volume 1, Issue 3, pp. 70-79, 2015. [2] A. Misam, N. Madhuri Magulakar, “Structural response of soft story high rise buildings under different shear wall location”. International Journal of Civil Engineering and Technology, Vol. 3, Issue 2, pp. 169–180, 2012. [3] A. Mortezaei , H. R. Rounagh , A. Kheyroddin, “Seismic evaluation of FRP strengthened RC buildings subjected to near-fault ground motions having fling step”, Composite Structures, pp. 1200-1211, 2010. [4] B.D. Prajapati and D. R. Panchal, “Study of Seismic and Wind Effect on Multi-Storey R.C.C., Steel and Composite Building”, International Journal of Advances in Engineering & Technology, Vol.6, No. 4, pp. 1836- 1847, 2013. [5] G. Dilip Kumar, A. B. S. Dadapeer, “Comparative Study of RCC and Composite Structures with Soft Storey using ETABS” International Journal of Scientific Research in Science and Technology, Volume 3, Issue 1, 2017. [6] F. Maison Bruce and E. Ventura Carlos , “Dynamic analysis of a thirteen storey building”, Journal of Structural Engineering, Vol. 117, No. 12, pp. 3783-3803, 1991. [7] J. C. Awkar and E.M. Lui, “Seismic analysis and response of multistory semi rigid frames”, Journal of Engineering Structures, Volume 21, Issue 5, pp. 425-442, 1997. [8] L. Saad , S.S. Jamkar, “Comparative Study of Wind Load Analysis of Buildings of Various Shapes and Sizes as per IS: 875 (Part III) and ASCE 7-02”, International Journal of Emerging Technology and Advanced Engineering, Vol. 5, No. 5, pp. 465-470, 2015. [9] Mehmet Alper Altuntop, “Analysis of building structures with soft stories”, October 2007. [10] M. R. Amin, P. Hasan, B.K. and M.A. Islam, “Effect of soft storey on multistoried reinforced concrete building frame.” 4th Annual Paper Meet and 1st Civil Engineering Congress, Dhaka, Bangladesh, December 22-24, 2011.

Copyright

Copyright © 2025 Joga Indu , Avinash Joshi . 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.