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
IMPACT OF SEISMIC PERFORMANCE OF AN RCC BUILDING WITH AND WITHOUT BRACING Abhijeet Kumar Das1, Afra Anam Provasha2 1 Graduate Student, Dept. of Civil Engineering, World University of Bangladesh, Dhaka, Bangladesh 2
Lecturer, Dept. of Civil Engineering, World University of Bangladesh, Dhaka, Bangladesh ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Seismic events pose significant threats to the
strength of preexisting structures. Bracing increases the capacity and lateral stiffness of the frame, which improves its seismic performance. By means of integrating the bracing system into the frame, a load from the frame would be redirected to the braces, which will be supported by micro trusses capable of carrying high forces, which will also result in the stiffening of the frame. When constructing buildings that will be subjected to lateral loads from earthquakes or wind, one effective design option is the structural steel framed system. Therefore, reinforced concrete frames with low lateral resistance might benefit from steel bracing systems that can be installed during retrofitting.
structural integrity of buildings, necessitating effective solutions to mitigate potential damages. This research paper investigates the seismic performance of a G+7 storey reinforced concrete (RCC) building with and without bracing by using ETABS software and response spectrum analysis to evaluate the dynamic response of the structure. This study employs a comparative approach to evaluate the effectiveness of X-bracing and V-bracing systems in enhancing the structural resilience of buildings subjected to seismic loads. Through comprehensive analysis, this research aims to provide insights into the seismic behavior of the RCC building with and without bracing. To measure how a structure reacts to seismic loads, engineers look at a number of performance metrics, including base shear, inter-story drift, lateral displacements, and story shear.
A soft storey is defined by BNBC-2020 as one whose lateral stiffness is less than either 70% of the storey above it or 80% of the average stiffness of the three storeys above it. The most typical type of vertical discontinuity results from an unanticipated consequence of infill materials in the upper floors. Typically, only the bare frame effect is taken into account when analyzing buildings, ignoring the effects of infill walls.
Key Words: Steel Bracing, Seismic Performance, Displacement, Reinforcement, Base Shear, Storey Drift, Response Spectrum, Steel Sections, ETABS.
1. INTRODUCTION
Today, designers and engineers are increasingly focused on earthquake resistance when analyzing and constructing buildings to mitigate seismic impact. They must handle a range of structures, from simple elements like poles to complex multi-story buildings and bridges, all of which face various loads, including seismic and dynamic forces. The design process involves selecting an appropriate structural system, calculating loads based on the building's purpose, and conducting structural analysis to predict behavior under specific conditions. This includes designing structural components to withstand different forces throughout the building's lifespan, particularly lateral seismic loads. The study adheres to the National Building Code of Bangladesh (BNBC 2020) for seismic design and analysis.
Buildings with reinforced concrete frames are widely used in construction due to their durability and strength. They may still be susceptible, nevertheless, to lateral forces brought on by earthquakes. Adding steel bracing systems is one way to lessen these stresses and enhance the seismic performance of such buildings. Steel bracing is made up of steel elements that are positioned carefully inside the structure to provide it more rigidity and strength. By absorbing and redistributing the energy produced during seismic events, these bracing can lessen lateral displacements and enhance the structural response as a whole. Two pivotal factors of how to resist a frame structure under the conditions of cross-stresses which occurs horizontally is with the live load method and bracing with steel is cost efficient. The most iconic structures on Earth have all made use of bracing, the primary retrofit method, to lateral stabilize their structures. The diagonals experience axial stress, which causes bracing to be effective. In order to maintain stiffness and strength against horizontal shear, minimum member sizes are required. Several methods are employed, such as cladding walls with slates, constructing shear walls, covering floor columns with an extra layer of mesh, and utilizing steel bracing. Enhance the ductility or
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2 LITERATURE REVIEW Various researches have been performed to review the seismic performances of the RC frames with different bracing systems, such as X-type and V-type bracing, or without bracing. Structural bracing enhances the displacement capacity of a building, and in high-rise RC structures, it is designed to resist lateral forces by increasing stiffness, strength, and energy dissipation. It also investigates different bracing configurations, such as diagonal, V, inverted and K-
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