International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 04 | Apr 2025
p-ISSN: 2395-0072
www.irjet.net
IDENTIFICATION OF OPTIMUM USE OF ISOLATION AND DAMPING SYSTEM FOR RCC REGULAR AND IRREGULAR BUILDINGS Agamoni Das 1, Debasish Bandyopadhyay 2 1 PhD Scholar, Dept. of Construction Engineering, Jadavpur University, Kolkata, West Bengal-700098, India 2 Professor, Dept. of Construction Engineering, Jadavpur University, Kolkata, West Bengal-700098, India
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Abstract - Seismic hazard refers to the probability or
design structure in DBE is done to ensure that the structure can survive moderate earthquakes without significant damage and that it provides a safe environment for occupants. The MCE represents a more severe earthquake scenario, often associated with the largest earthquake that could reasonably be expected in a region over the lifetime of the structure. Under MCE conditions, the structure may experience significant damage, such as cracking, permanent deformation, or failure of non-essential systems. However, the key objective is for the building to not collapse. The structure should maintain its stability and not pose a danger to occupants, but repairs will likely be needed afterward.
likelihood of certain levels of ground shaking (earthquake intensity) occurring in a specific region over a given period of time. Seismic hazard assessment is typically a map or model that shows areas with varying levels of earthquake hazard, based on the potential for ground shaking, faulting, and other seismic phenomena. Seismic risk is typically assessed by combining seismic hazard data with information on the exposure and vulnerability of a region. It is a measure of the potential impact of earthquakes on people, buildings, infrastructure, and the environment. Seismic disaster mitigation techniques are being adopted which causes reduction in earthquake forces by different methods. The proposed paper investigates the ability of base isolation and energy absorption systems using rubber isolators and fluid viscous dampers to protect the structure by controlling seismic response. Concrete building structures of regular and irregular type have been modelled in SAP 2000 for various story heights of G+5 & G+15 building. Non-linear Time history has been performed for both conventional and isolated buildings. Seismic responses e.g. base shear, max drift/displacement etc. have been compared for the conventional and isolated structures for each of the building models with same seismic considerations. The optimum zone for selection of the ideal combination of isolation and damping system has been identified for all the building types from the parametric study of change in isolation and deformation ratio using various stiffness and damping properties.
Seismic disaster mitigation involves a range of strategies designed to reduce the impact of earthquakes. There are several methods for making structures safe against earthquake; earthquake resistant design using Base isolation and damping systems, retrofitting existing structures etc. Base isolation is one of the most effective seismic disaster mitigation techniques used to protect buildings and infrastructure from earthquake damage ([4], [5], [12]). It involves placing a building or structure on bearings (known as isolators) that allow the building to move independently from the ground motion during an earthquake. This technique reduces the amount of seismic energy transmitted to the building, helping to minimize damage and enhance the safety and resilience of the structure. Base isolation can be applied to a wide range of structures, from residential buildings to large, complex infrastructure projects for both the conditions; retrofitting and new construction. Base isolation technique includes some isolation devices between top and bottom structure and uses the stiffness to lengthen the time period of the entire structure and thus reduces the seismic force to a desired level. Seismic dampers are devices that absorb and dissipate the energy generated by an earthquake, reducing the amount of shaking experienced by a building or structure.
Key Words: Base Shear; Non-linear; Energy absorption; Damping; Isolation ratio; Deformation ratio
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INTRODUCTION
Seismic disaster mitigation for structures is of paramount importance because it directly affects the safety, stability, and functionality of buildings and infrastructure during an earthquake. It aims to anticipate and minimize the risks associated with earthquakes, leading to safer communities, less economic loss, and quicker recovery in the aftermath. When designing structures for seismic conditions, engineers consider two main earthquake scenarios: the Design Basis Earthquake (DBE) and the Maximum Considered Earthquake (MCE). These scenarios help determine how much seismic force a structure should be able to withstand during an earthquake, guiding the design of the structure's components to ensure safety, stability, and performance. The
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Among the many supplemental base isolation and energy dissipation devices proposed and implemented for earthquake hazard mitigation, elastomeric bearings and fluid viscous dampers seem to be a popular solution in recent applications. Effectiveness of the isolator and damper behavior depends on the non-linear viscous characteristics of isolators. For elastomeric isolators (EB) elastic stiffness helps in making structure flexible and base isolated with larger time period whereas fluid viscous dampers (FVD)
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