Study of Tall Structures Subjected to Seismic Forces with Irregular Structural Forms

Abstract

The advancement of technology and the increased economic development of the countries have brought about a new era in construction of high-rise buildings. With the significant improvement in construction technology it is witnessed that new structural systems being adopted in the design of tall buildings. One among them is the irregular structural system. Irregular structural system resists lateral loads. In the present study, a 45-storey high rise structure is considered. Five different irregular structural forms are modelled using ETABS software. The models such as simple framed structure, simple tube structure, tube in tube, bundled tube and hybrid tube structure is considered. Models are analyzed for static and dynamic response spectrum analysis. The results are extracted and compared. The conclusions are as below. The Displacement values of static and dynamic analysis are not same and having a difference of around 25%. This is a huge reduction. The dynamic analysis is more suitable for high rise building and it is proved to be economical in terms of displacement and reduces the major construction cost by reducing unnecessary increase in member sizes.

Introduction

I. INTRODUCTION

A multi-story building is a building that has multiple floors above ground. Multi-story buildings aim to increase the floor area of the building without increasing the area of the land. The multi-story building can be transformed to tall building to increase the floor space further more. A building whose height creates different conditions in the design, construction, and use than those that exist in common buildings of a certain region and period. The irregular structural tall building design is influenced by the lateral loads such as wind, seismic, etc.

The advancement in construction field is increased day by day. The numbers of buildings, height of building is increased. The effect of lateral load is increased with respect to the increase of height. Modern construction methods and structural systems are to be introduced to enhance the structural safety. Different types of structural systems are to be used to resist the effect of lateral loads on the buildings. Rigid frame structures, braced frame structures, shear wall frame structures, outrigger systems, irregular structural are the different types of structural systems used in the buildings to enhance structural safety by reduce the effect of lateral loads on the buildings. The irregular structural are widely used and which is to be considered as a better structural system for tall buildings.

II. MATERIALS AND METHODOLOGY

Here models are proposed to have 50 storey RCC irregular structures with various forms. The Following tables gives the information on the data considered for modelling and analysis.

IV. FUTURE SCOPE

1. Further different levels of steel and RCC structure can be analyzed.
2. The Steel and RCC combination can be checked for low rise structure to assess the performance.

Conclusion

1) The Displacement values of static and dynamic analysis are not same and having a difference of around 25%. This is a huge reduction from static and dynamic analysis, hence dynamic analysis is must in tall structure. 2) The Model 3 is having very less displacement compared to all other models. This proves that this model is having highest stiffness comparatively. 3) The model 5 is having highest displacement compared to all other model, this is due to the steel structure is having highest flexibility which is decreasing the stiffness drastically. 4) The limiting value depends on the storey height i.e., h/250 = 3000/250 = 12. However, model 5 at steel concrete junction level, its drift values are exceeding. And it is not acceptable. It is required to provide bracing of other strengthening measure to reduce the drift values. 5) From the overall analysis, it can be concluded that, the hybrid structure is having very less displacement and more economical in every aspect.

References

[1] Lavanya.T1, Sathyanarayana Sridhar.R2, “Dynamic analysis of irregular structural buildings”. [2] R.Ramasubramani , G.Pennarasi, S.Sivakamasundari, “Differential Settlement in Various irregular structural Systems”. [3] Sharadrao Patil1 and Uttam Kalwane 2, “Shear Lag in irregular structural Structures”. [4] Hooman Mazlooma , Maryam Firoozi Nezamabadi*,b, “Performance of Mid-rise Buildings with Tubular Structure Under the Effect of Near Field Earthquakes”. [5] Ray P. S. Han, “Analysis of framed tube structures of arbitrary sections”.

Copyright

Copyright © 2023 Anusha P. 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.