Effects of Base Uplifting on the Seismic Response of Unanchored Liquid Storage Tanks

2012 ◽  
Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Hydrodynamic Pressure ◽  
Base Plate ◽  
Seismic Loading ◽  
Storage Tanks ◽  
Liquid Storage ◽  
Detailed Simulation ◽  
Steel Tank ◽  
Static Pushover Analysis

Unanchored liquid storage tanks under strong earthquake loading tend to uplift. In the present study, the effects of base uplifting on the seismic response of unanchored tanks are presented with emphasis on elephant’s foot buckling, base plate strength and shell-to-base connection capacity. Towards this purpose, base uplifting mechanics is analyzed through a detailed simulation of the tank using non-linear finite elements, and a static pushover analysis is conducted that considers the hydrodynamic pressure distribution due to seismic loading on the tank wall and the base plate. The uplifting provisions from EN 1998-4 and API 650 Appendix E standards are briefly described. Numerical results for a typical 27.8-meter-diameter steel tank are compared with the above design provisions.

Rocking and Slip Coupled Seismic Response of Large and Flexible Cylindrical Storage Tanks

2007 ◽  
Author(s):  
Nobuyuki Kobayashi ◽  
Noriaki Seo ◽  
Masahiro Watanabe ◽  
Friedrich Pfeiffer
Keyword(s):  
Seismic Response ◽  
Mechanical Model ◽  
Degrees Of Freedom ◽  
Hydrodynamic Pressure ◽  
Base Plate ◽  
Shaking Table ◽  
Scale Model ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Rocking Motion

The slip and rocking coupled response of the unanchored flexible cylindrical storage tanks due to the seismic excitation is investigated. A five-degrees of freedom mechanical model is developed in order to examine the slip and rocking coupled seismic response accompanied with the uplifting of the base plate. The model takes into account the flexibility of the tank shell and bottom plate, the hydrodynamic pressure effect of the contained liquid to the tank shell and bottom plate as well as the slip and rocking motion introducing the unilateral contact. The validity of the presented mechanical model is demonstrated by the shaking table experiments with a scale model tank. As the numerical simulations results, it is clarified that slip and rocking coupled motion gives significant effect on the seismic response of the tank, and the taller tank is easier to slip than the broader ones is.

scholarly journals Response of Base-Isolated Liquid Storage Tanks

2004 ◽  
Vol 11 (1) ◽  
pp. 33-45 ◽  
Author(s):  
M.B. Jadhav ◽  
R.S. Jangid
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Equations Of Motion ◽  
Approximate Model ◽  
Storage Tanks ◽  
Step Method ◽  
Earthquake Excitation ◽  
System Parameters ◽  
Liquid Storage ◽  
Isolation Systems

Seismic response of liquid storage tanks isolated by elastomeric bearings and sliding system is investigated under real earthquake ground motions. The continuous liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The coupled differential equations of motion of the system are derived and solved in the incremental form using Newmark's step-by-step method with iterations. The seismic response of isolated tank is studied to investigate the comparative effectiveness of various isolation systems. A parametric study is also carried out to study the effect of important system parameters on the effectiveness of seismic isolation for liquid storage tanks. The various important parameters considered are: (i) aspect ratio of the tank and (ii) the time period of the isolation systems. It was observed that both elastomeric and sliding systems are found to be effective in reducing the earthquake forces of the liquid storage tanks. However, the elastomeric bearing with lead core is found to perform better in comparison to other systems. Further, an approximate model is proposed for evaluation of seismic response of base-isolated liquid storage tanks. A comparison of the seismic response evaluated by the proposed approximate method and an exact approach is made under different isolation systems and system parameters. It was observed that the proposed approximate analysis provides satisfactory response estimates of the base-isolated liquid storage tanks under earthquake excitation.

Investigation on Buckling Behavior of Cylindrical Liquid Storage Tanks Under Seismic Loading: 3rd Report — Proposed Design Procedure Considering Dynamic Response Reduction

2003 ◽  
Author(s):  
Akihisa Sugiyama ◽  
Koji Setta ◽  
Yoji Kawamoto ◽  
Koji Hamada ◽  
Hideyuki Morita ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Seismic Loading ◽  
Absorption Capacity ◽  
Reduction Factor ◽  
Storage Tanks ◽  
Energy Absorption Capacity ◽  
Design Guideline ◽  
Response Reduction Factor ◽  
Liquid Storage ◽  
Thin Walled

As for thin walled cylindrical liquid storage tanks in nuclear power plants, the current elastic design guideline against seismic loading might result in too conservative component design as compared with elasto-plastic design in general industries. Therefore, it is thought possible to make the design guideline more reasonable by taking dynamic response reduction into account. In this series of study, experiments using scaled models were carried out, and seismic behavior of thin walled cylindrical liquid storage tanks was simulated to investigate energy absorption capacity and seismic resistance of those tanks. In this 3rd report of series of studies, seismic behavior of tanks was simulated to estimate a dynamic response reduction factor. This factor is based on the energy absorption capacity of structures. Through experiments and numerical study, a response reduction factor to design thin walled cylindrical liquid storage tanks has been proposed.

Generalized SDOF system for dynamic analysis of concrete rectangular liquid storage tanks: effect of tank parameters on response

2010 ◽  
Vol 37 (2) ◽  
pp. 262-272 ◽  
Author(s):  
J. Z. Chen ◽  
M. R. Kianoush
Keyword(s):  
Dynamic Response ◽  
Natural Frequencies ◽  
Hydrodynamic Pressure ◽  
Characteristic Parameter ◽  
Added Mass ◽  
Tank Wall ◽  
Storage Tanks ◽  
Effective Height ◽  
Sdof System ◽  
Liquid Storage

This paper presents the results of parametric studies on the seismic response of concrete rectangular liquid storage tanks using the generalized single-degree-of-freedom (SDOF) system. The effects of height of liquid and width of tank on the dynamic response of liquid storage tanks are investigated. The liquid level varies from the empty condition to a full tank. Also, instead of the commonly used ratio of width of tank to liquid height, Lx/HL, the ratio of width of tank to full height of the tank wall, Lx/Hw, is used as a characteristic parameter of tanks to study the effect of tank size on the dynamic response. The trends of added mass of liquid, effective height, and natural frequencies for different sizes of tanks are established. The values of the added mass of liquid due to impulsive hydrodynamic pressure and the effective height in the relationship with the ratios Lx/Hw and HL/Hw are determined and can be used in the seismic design of liquid storage tanks. Since the natural frequencies of liquid-containing structures are within a band of frequencies between that of a full tank and that of an empty tank, the recommended frequency to be used in the design of the tank wall is the frequency that causes the maximum dynamic response .

Seismic response analysis of adjacent liquid-storage tanks

2016 ◽  
Vol 45 (11) ◽  
pp. 1779-1796 ◽  
Author(s):  
Konstantinos Mykoniou ◽  
Christoph Butenweg ◽  
Britta Holtschoppen ◽  
Sven Klinkel
Keyword(s):  
Seismic Response ◽  
Response Analysis ◽  
Storage Tanks ◽  
Seismic Response Analysis ◽  
Liquid Storage
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