International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 12 | Dec 2024
p-ISSN: 2395-0072
www.irjet.net
DYNAMIC RESPONSE OF A TYPICAL RC FRAME WITH HYBRID BRACING SYSTEM Desai Abhishek Annasaheb1, Dr. Chethan K2 1P.G Student, Department of Civil Engineering, U.V.C.E, Bangalore University, Bengaluru
2Associate Professor, Department of Civil Engineering, U.V.C.E, Bangalore University, Bengaluru.
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Abstract - Steel bracing systems play a key role in ensuring
Overall, incorporating steel bracings in high-rise buildings is vital for ensuring safety, stability, and structural integrity, making it a fundamental consideration for engineers and architects involved in the design and construction of tall structures.
the stability of high-rise buildings by effectively resisting lateral forces induced by wind, seismic activity and other dynamic loads. Various types of steel bracing systems are used in high-rise buildings focusing on their design considerations, performance under different loading conditions and the impact on overall building stability. The objective is to provide a comprehensive understanding of bracing systems, highlighting their importance in modern high-rise construction and offering insights into the selection of optimal bracing solutions to achieve a balance between safety, cost effectiveness and sustainability. In this study, RC Frame of G+15 stories is considered with different steel braces along with hybrid bracing system for the Finite Element Analysis. The performance of building is studied in terms of Modal, Equivalent Static and Response Spectrum analysis. Time Period, Base shear, Displacement and Storey Drift results are obtained, tabulated and conclusions are drawn.
1.1 Concentric Bracing System The steel braces are usually placed in vertically aligned spans. This system allows to obtaining a great increase of stiffness with a minimal added weight. Concentric bracings increase the lateral stiffness of the frame thus increases the natural frequency and also usually decreases the lateral storey drift. Concentric bracing are designed to be in pure axial compression or tension when lateral loads are applied. When wind or seismic forces push or pull on the building, the braces either compress or stretch, transferring the load through the diagonal braces to the columns and beams, which in turn transfer the forces to the foundation. This system operates based on the concept of axial load transfer, which makes it effective in resisting lateral forces without inducing bending or significant deformation in the frame.
Key Words: Cross-bracing, V-bracing, Inverted V-bracing, diagonal braces, Time Period, Base Shear, Storey Displacement and Storey Drift.
1.2 Eccentric Bracing System The eccentricity in the bracing system introduces a combination of both shear and bending forces, allowing the braces to resist larger lateral loads more efficiently. The braces work to absorb lateral forces by "deforming" at the connection point, often through a plastic hinge mechanism where the braces or connections yield, dissipating energy from seismic forces. The eccentric nature of the bracing allows for a more flexible system, which can dissipate energy more effectively during seismic events, reducing the amount of force transmitted to the overall structure. The energy dissipation through the yielding of braces or joints makes the system especially useful in earthquake-resistant designs.
1.INTRODUCTION Steel bracings are a crucial component in the structural design of high-rise buildings, providing essential stability and resistance against lateral forces such as wind and earthquakes. These forces can cause significant displacement and deformation in a structure, and steel bracing systems are designed to minimize this by enhancing the building's rigidity and strength. The use of steel bracings in high-rise construction offers several advantages, including improved load-bearing capacity, cost-effectiveness, and ease of installation. Steel’s high strength-to-weight ratio makes it an ideal material for supporting large loads while maintaining a relatively light structure. Furthermore, steel bracing systems can be tailored to meet the specific demands of different building designs, offering flexibility in layout and appearance. Bracing systems can take various forms, including diagonal braces, cross-bracing, and momentresisting frames, each offering unique benefits in terms of performance and aesthetic integration. The choice of bracing type depends on factors such as the height of the building, its location, and the type of loads it is expected to encounter.
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2. OBJECTIVES 1. To evaluate the Dynamic Response of a Typical RC
Bare Frame with various bracing systems subjected to seismic loads. Bracing system used in this study are X, V, Inverted V and Diagonal Bracings. 2. To evaluate the Dynamic Response of a Typical RC Bare Frame with combination of the bracing systems called as “Hybrid Bracing System”.
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