Evaluation of Storage Tank Floating Roofs for Stress and Stability Due to Earthquake Induced Liquid Sloshing

2007 ◽  
Author(s):  
Philip J. Cacciatore ◽  
Benjamin F. Hantz ◽  
L. Magnus Gustafsson
Keyword(s):  
Liquid Fuel ◽  
Theoretical Foundation ◽  
Liquid Sloshing ◽  
Storage Tanks ◽  
Analysis Method ◽  
Seismic Belt ◽  
Oil Storage ◽  
Fire Disaster ◽  
Work Done ◽  
Tank Geometry

Considerable interest has developed in the engineering community concerning the damage to the floating roof of oil storage tanks due to liquid sloshing from earthquake loading. Engineering groups in countries bordering the circum-Pacific seismic belt in particular are devoting extensive efforts to obtaining solutions capable of identifying vulnerable roof designs and developing modifications to improve strength. The recent efforts of the Japanese Fire Disaster and Management Authority (FDMA) as a result of 1995 Kobe and the 2003 Tokachi-Oki earthquakes are examples of recent work in this area. This paper focuses on efforts to analyze floating roof structures for stress and stability under typical earthquake velocity spectrums using advanced finite element methods. It employs ideas included in the Japanese FDMA studies, work done as part of the ASCE Committee on Gas and Liquid Fuel Lifelines, and some original methods developed at ExxonMobil. It has been applied to several tank designs and been submitted as a suitable advance analysis method to the Japanese FDMA. The paper provides both the theoretical foundation as well as an example covering typical tank geometry.

Seismic Response Analysis of Flexible Drain System Into External Floating Roof Storage Tanks

2017 ◽  
Author(s):  
Gary Bernard ◽  
Damien Vera ◽  
Weng Kheong Lim
Keyword(s):  
Dynamic Analysis ◽  
System Analysis ◽  
Liquid Sloshing ◽  
Response Analysis ◽  
Minimal Risk ◽  
Storage Tanks ◽  
Analysis Software ◽  
Drain Pipe ◽  
Oil Storage ◽  
Pipe Systems

Floating roofs are commonly used worldwide on top of cylindrical oil storage tanks as a primary means to prevent formation of vapor above stored products into the storage tanks and should provide a safe and efficient storage of products with minimal risk for the environment. However, aboveground storage reservoirs built in seismic zones are prone to earthquake damage. Extensive research has been done to enhance performance of the floating roof tanks against damage to ground foundations, fixed and floating roof, tank shells as well as adjacent piping. Indeed, the stored oil sloshing in a cylindrical storage tank is known to have caused damage to the tank shell, tank roof and as well to anti-rotation columns. One of the possible dangers of liquid sloshing is the resultant damage to in-situ roof drain systems within external floating roof tanks. Indeed, roof drain systems are designed for continuous withdrawal of rainwater from external floating roofs, and if damaged, would result in dysfunction of the systems and irreversible discharge of oil products into the containment dyke. In this regard, a reliable roof drain system should have the capability to withstand liquid sloshing effects, and to a certain degree, ensure resistance in events of displacement of the floating roof. The aim of this document is to use knowledge of flexible pipe technology and industry recognized dynamic analysis software to analyze the effects of earthquakes on the integrity of a flexible drain pipe system. Analysis of liquid sloshing effects on flexible drain pipe systems using dynamic analysis software will be presented and the effects of structural damages such as loss of anti-rotation columns on the integrity of flexible drain pipe systems will be assessed. In the end, the document will propose recommendations on how industry can further enhance roof drain systems within external floating roof tanks to ensure performance and functionality after occurrence of earthquakes.

Liquid Sloshing of Oil Storage Tanks due to the 2003 Tokachi-oki Earthquake

2004 ◽  
Vol 2004.6 (0) ◽  
pp. 21-22
Author(s):  
Shinsaku ZAMA ◽  
Minoru YAMADA ◽  
Haruki NISHI ◽  
Ken HATAYAMA ◽  
Masahiro HIROKAWA
Keyword(s):  
Liquid Sloshing ◽  
Storage Tanks ◽  
Oil Storage

Seismic Design of Floating Roof of Oil Storage Tanks Under Liquid Sloshing

2006 ◽  
Author(s):  
Yoshihiko Yamauchi ◽  
Asamichi Kamei ◽  
Sinsaku Zama ◽  
Yoshinori Uchida
Keyword(s):  
Wave Height ◽  
Seismic Design ◽  
Response Spectrum ◽  
Nonlinear Behavior ◽  
Liquid Sloshing ◽  
Storage Tanks ◽  
Natural Period ◽  
Oil Storage ◽  
Deck Plate ◽  
Sloshing Mode

The 2003 Tokachi-oki earthquake caused the severe damage to oil storage tanks by liquid sloshing. Especially at Tomakomai in Hokkaido, the ground motions at the periods of 3 to 8 sec predominated, which were harmonized with the natural period of liquid sloshing of oil storage tanks, then seven single-deck-type floating roofs were damaged and sank. For the 30,000kl FRT(φ 42.7m), one of those tanks, with about 7 see of fundamental sloshing period, maximum sloshing wave height was estimated 3m and over. On the other hand, for the 100,000kl FRT(φ 78.2m) with about 12 sec of fundamental sloshing period, maximum sloshing wave height was estimated about 1.5m and the excitation of 2nd sloshing mode was considered to be strongly excited. Considering both of nonlinear behavior of a large amplitude wave of 1st sloshing mode and nonlinear effects of large deflection of a deck plate at 2nd sloshing mode, we established the simplified method of seismic design of single-deck-type floating roofs using modified velocity response spectrum. This spectrum was based on many studies, investigated by Zama [1] and others, of the prediction of long-period strong ground motion and of liquid sloshing of oil tanks in Japan.

Liquid Sloshing of Oil Storage Tanks and Long-Period Strong Ground Motions in the 2003 Tokachi-Oki Earthquake

2004 ◽  
Author(s):  
Shinsaku Zama
Keyword(s):  
Seismic Waves ◽  
Ground Motions ◽  
Liquid Sloshing ◽  
Response Analysis ◽  
Storage Tanks ◽  
Severe Damage ◽  
Long Period ◽  
Oil Storage ◽  
Wave Heights ◽  
Strong Ground

The 2003 Tokachi-oki earthquake caused the severe damage to oil storage tanks by liquid sloshing. Especially at Tomakomai, two tank fires broke out and six floating roofs sank. Seismograms showed that long-period motions were predominant and duration became longer when the seismic waves propagated into the Yufutsu Plain, where Tomakomai is located. Sloshing wave heights (Wh) of all tanks were calculated by two-dimensional response analysis. It was found that estimated Wh exceeded 3 m at periods 5 and 7.5 sec, and exceeded 2m from 3.5 to 9 sec of sloshing period and that severe damaged tanks had the highest Wh at each period in general.

CHARACTERIZATION OF SLUDGE WAXES FROM CRUDE OIL STORAGE TANKS HANDLING OFFSHORE CRUDE

1997 ◽  
Vol 15 (7-8) ◽  
pp. 755-764 ◽  
Author(s):  
S.A. Fazal ◽  
R. Rai ◽  
G.C. Joshi
Keyword(s):  
Crude Oil ◽  
Storage Tanks ◽  
Oil Storage

Simplified Development Method of FEA Code for Sloshing of Floating Roof Tanks (Lagrangian Formulation for Axisymmetric Linear Problem)

2014 ◽  
Author(s):  
Shoichi Yoshida
Keyword(s):  
Linear Problem ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Computational Time ◽  
Storage Tanks ◽  
Coupling Vibration ◽  
Development Method ◽  
Oil Storage ◽  
Fluid Behavior ◽  
Computer Codes

Floating roofs are widely used to prevent evaporation of content in large cylindrical aboveground oil storage tanks. The 2003 Hokkaido Earthquake caused severe damages to the floating roofs due to sloshing. These accidents became a cause to establish structural integrity of the floating roof tanks in sloshing. However, many designers do not have a solution for the sloshing of floating roof tanks except for three-dimensional FEA computer codes. The three-dimensional FEA requires a long computational time and expenses. The sloshing of floating roof tanks is a coupling vibration problem with fluid and structure. The simplified and convenient method has been desired for this solution. This paper presents a simplified development method of a FEA code in the axisymmetric linear problem. It is performed to modify an existing structural analysis code. The fluid behavior is formulated in terms of displacement as the Lagrangian approach.

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