International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 07 | Jul 2023
p-ISSN: 2395-0072
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Parametric Study of Elevated Water Tank with Metallic and Friction Damper Swaty Arun1, Deepa H Raval2 1PG student, Applied Mechanics Department, L.D. College of Engineering, Gujarat, India 2Assistant Professor, Applied Mechanics Department, L.D. College of Engineering, Gujarat, India
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external source of energy for activation. Passive control devices do not require any external energy and only require earthquake forces to act. Semi active devices require some external energy to activate. These are modification of passive control devices. Since passive control devices do not require external source to operate it can be a viable solution for seismic retrofit as well as rehabilitation of structures. Passive control devices convert lateral forces induced by earthquake into other forms of energy such as heat energy [4]. Supplemental energy dissipation system and seismic isolation system comes under passive energy dissipation devices. Devices such as dampers comes under supplemental control system whereas base isolation and multi-story isolations come under seismic isolation system. Optimization of dampers can result in economic design and is done in various literatures. Optimal design of metallic and friction dampers is proposed by Moreschi et al [9]. On installation of isolation devices time period of the structure increases and whereas there is a decrease in time period on application of dampers.
Abstract – Present research attempts to find the response of RC elevated water tank with metallic dampers. Analytical investigation of metallic damper and friction damper in reducing seismic response of an Elevated Water Tank is done using different time history. Seismic response parameters such as base shear, base moment, time period, top staging displacement and sloshing displacements are evaluated and compared. Key Words: Time history, Seismic response, Elevated water tank, Metallic damper, Friction damper
1. INTRODUCTION Many structures such as bridges buildings etc. damaged in previous earthquakes. Important structures such as water tanks hospitals etc. should remain functional even after an earthquake. Failure of water tanks makes evacuation and rehabilitation during earthquakes worse. All structures irrespective of its importance should be designed for lateral forces induced during ground motions. Performance of elevated water tanks during Bhuj earthquake was studied by Durgesh C Rai [11].
1.2 X - PLATE METALLIC DAMPER (XPD) Generally metallic dampers are made of steel, aluminum, copper, lead, and shape memory alloys. Mild steel is the most commonly used material as a metallic damper. Steel material can be simplified as a bilinear or trilinear elastoplastic model. Hence these dampers are also called elastoplastic dampers. These dampers are also called hysteretic dampers. These dampers are also yielding dampers as dissipation of energy occurs by yielding of metals.
Generally, water tanks are designed for deadloads, live loads, and forces due to wind and earthquakes. Selection of type of water tank is a crucial step in design of water tanks. Intze type tanks are very economical as it reduces the size of bottom ring beam.
1.1 SEISMIC CONTROL DEVICES
XPD is a type of metallic damper which consists of a series of X shaped plates arranged parallelly. These can be connected diagonally or on top of chevron bracing etc. This type of dampers was introduced by Kelly et.al [15]. XPD’s made of steel undergoes many cycles until it reaches the yield limit [1]. These dampers showed good response reduction in piping systems [10]. The properties of an XPD can be derived using beam theory which is done after a series of tests. Initially XPD is assumed to be made of two triangular plates and properties such as stiffness and yield strength is found out. Fig 1 shows a typical diagram of an XPD with holding devices.
Conventional seismic design method, overall safety, and safety of structures against earthquake, are designed and constructed to have sufficient strength. The traditional design methodology is quite expensive. The use of passive control devices results in reduction of seismic design forces on the building [14]. This method uses an external source of energy to resist lateral forces due to earthquake. Vibrations induced by wind or earthquake forces can be diminished without increasing the strength of the structure by addition of structural control devices. Generally seismic control devices are classified into active, passive, and semi-active. Active control devices require an
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