Response of Elevated Liquid Storage Steel Tank with Variable Frequency Pendulum Isolator
Poonam S. Sutar1, S. C. Potnis2, S. K. Bhor3, Vinayak Sutar4
1Poonam S. Sutar, Dept. of Civil Engg, JSPM’s Rajarshi Shahu College of Engg.,Pune,India.
2Dr. S. C. Potnis, Dept. of Civil Engg, JSPM’s Rajarshi Shahu College of Engg., Pune, India, Mobile No. 9890436536,
3S. K. Bhor, Dept. of Mech. Engg, JSPM’s Rajarshi Shahu College of Engg., Pune, India.
4Vinayak Sutar, Dept. of electronics Engg., D.K.T.E. College of Engg., Ichalkaranji, India.
Manuscript received on October 08, 2013. | Revised Manuscript Received on October 21, 2013. | Manuscript published on October 20, 2013. | PP: 31-36 | Volume-1, Issue-11, October 2013. | Retrieval Number: K03341011113/2013©BEIESP
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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The seismic response of liquid storage steel tanks with the variable frequency pendulum isolator (VFPI) is compared with that of the same liquid storage steel tanks isolated using the linear elastomeric bearings under real earthquake ground motion. In order to measure the effectiveness of isolation system, the seismic response of isolated steel tanks is compared with that of the non-isolated steel tanks. Two types of isolated tank models are considered in which the bearings are placed at the base and top of the steel tower structure. The seismic response is obtained by the Newmark’s step-by-step method. The response of two types of tanks, namely slender and broad tanks, is obtained and a parametric study is carried out to study the effects of important system parameters on the effectiveness of seismic isolation. The various important parameters considered are the tank aspect ratio, the time period of tower structure, damping and the time period of isolation system. Further, a parametric study has been carried out to examine the behavior of liquid storage steel tanks isolated with VFPIs. The important parameters considered are the friction coefficient of the VFPI, the Frequency Variation Factor (FVF) of the VFPI and the tank aspect ratio. It is observed from proposed analysis that the seismic response of elevated steel tanks accurately with significantly less computational efforts. It is concluded that seismic response, viz. the base shear, the sloshing displacement and the impulsive displacement, of liquid storage steel tanks during earthquake ground motions can be controlled with the installation of the VFPI. The linear elastomeric bearings and VFPI isolators has almost the same effect in the tank to the far-field ground motions. MATLAB software has been used for analysis and solving all dynamic equations of motion. The isolation is very effective in reducing the seismic response of elevated liquid storage tanks.
Keywords: aspect ratio, isolation system, liquid storage steel tank, system parameters.