International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 11 Issue: 06 | Jun 2024
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p-ISSN: 2395-0072
Seismic Analysis of Braced Reinforced Concrete Building Frame with Effect of Base Isolation Prof. Ganesh C. Jawalkar1, Uzma Kausar A. Haranmare2, Prof. Rameez R.Badeghar3 1Lecturer at N.B. Navale Sinhagad College of Engineering, Solapur, Maharashtra, India-413255
2Research Scholar at N.B. Navale Sinhagad College of Engineering, Solapur, Maharashtra, India-413255 3Lecturer at N.B. Navale Sinhagad College of Engineering, Solapur, Maharashtra, India-413255 ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Here in this paper we discuss different structural
structures must possess both vertical load-bearing capacity and lateral stiffness to withstand these forces effectively.
control systems such as bracings and base isolators are employed using ETABS software, with ground motion data assigned as per codes. Various low-rise and mid-rise building frames with low damping and flexibility are analyzed to mitigate unwanted vibrations. The results of the seismic response of each control system and their combinations in lowrise and mid-rise building models are compared with conventional building methods and various other control systems through response spectrum analysis.
Various bracing techniques, including concentric, eccentric, and knee bracing, have been utilized over the years to effectively control lateral displacements. Bracing proves to be highly efficient and cost-effective in stiffening framed structures against lateral stresses, thereby reducing the need for large member sizes. Consequently, the bracing system significantly reduces lateral and torsional movements during seismic loading.
Key Words: ETABS software, Base isolator, low rise building, high rise building, Response spectrum analysis, seismic response.
1.2 Base Isolation Base isolation is a smart way to make buildings safer during earthquakes. It separates the building's base from the rest of the structure using flexible joints. These joints, called isolators, absorb a lot of the earthquake's energy, so the building shakes less. Unlike regular buildings, where everything moves together during an earthquake, in base isolated buildings, only the top part moves slightly, which keeps it safer. This means base isolated buildings can stay strong and safe even during big earthquakes without needing any extra help..
1.INTRODUCTION Traditional approaches to seismic design of building structures have long focused on enhancing stiffness, strength, and ductility. However, this often leads to increased structural member size and material consumption, amplifying both building costs and seismic reactions. Consequently, the effectiveness of the standard seismic design method is limited. In response, various vibrationcontrol strategies, categorized as structural controls, have emerged, marking significant advancements in recent years. The field of structural control encompasses diverse techniques, including active, passive, hybrid, and semi-active control systems. Passive vibration control, such as base isolation, operates without external power sources, utilizing structural motion to generate control forces. This method effectively elasticizes buildings, ensuring safety during seismic events. Bracing systems offer substantial compression strength, particularly when integrated with surrounding frames to bolster lateral load resistance. In steel frames, bracings serve as diagonal compression struts, efficiently distributing compressive forces to adjacent joints.
2. Response Spectrum Analysis This approach proves invaluable for analyzing structures where in primary modes exert a significant influence on overall response. It involves determining the response of a multi-degree of freedom system through the superposition of modal responses. Each modal response is derived from spectral analysis of single-degree of freedom systems, which are then integrated to ascertain the total response. Widely utilized across various industries, the Response Spectrum Method represents a linear dynamic technique used to estimate structural response during short, nondeterministic, and transient dynamic events, such as earthquakes and shocks. Estimation is typically achieved through either the Complete Quadratic Combination (CQC) or Square Root of the Sum of the Squares (SRSS) method, with SRSS favored for widely spaced frequencies and CQC for closely spaced ones. This method operates within the linear range to determine the peak structural response of a building and subsequently identify the lateral forces it experiences..
1.1 Bracing Systems The primary objective of structural systems in construction is to efficiently transfer gravity loads. Gravity loads typically include dead load, active load, and snow load. Lateral loads, such as wind or seismic forces, can induce high stresses, sway movement, and vibration in structures. Therefore,
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