scholarly journals LABORATORY AND PLANT: GAUGING OF STORAGE TANKS--METHOD OF ACCURATELY AND RAPIDLY DETERMINING THE VOLUME CONTENT OF MATERIAL IN HORIZONTAL CYLINDRICAL TANKS WITH BUMPED HEADS

1916 ◽  
Vol 8 (5) ◽  
pp. 430-433
Author(s):  
K. B. Howell
Keyword(s):  
Volume Content ◽  
Storage Tanks ◽  
Cylindrical Tanks

Consideration of Wind Loads in Fitness for Service Assessment of Storage Tanks

2020 ◽  
Author(s):  
Gys van Zyl ◽  
Stewart Long
Keyword(s):  
Wind Pressure ◽  
Wind Loads ◽  
Wind Loading ◽  
Storage Tanks ◽  
Actual Distribution ◽  
Wind Actions ◽  
Level 3 ◽  
Tank Design ◽  
Cylindrical Tanks ◽  
Direct Guidance

Abstract Wind actions are important to consider when performing fitness for service assessment on storage tanks with damage. Tank design codes typically have rules where a design wind velocity is used to determine required dimensions and spacing of wind girders, and a uniform wind pressure is used to evaluate tank anchorage for uplift and overturning due to wind actions. These rules are of little use in a fitness for service assessment of localized damage, as the actual distribution of wind pressure on the wall and roof of a cylindrical tank is far from constant, and a better evaluation of the wind pressure distribution is desired when performing a level 3 fitness for service assessment. API 579/ASME FFS-1 provides no direct guidance relating to the application of wind loading but refers to the American Society of Civil Engineers Standard ASCE/SEI 7. Other international codes relating to wind loads, such as Eurocode EN-1991-1-4 and Australia/New Zealand Standard AS/NZS 1170.2 also contain guidance for the evaluation of wind actions on cylindrical tanks. This paper will present a review of these international codes by comparing their guidance for wind actions on cylindrical tanks, with specific emphasis on how this may affect a level 3 fitness for service assessment of a damaged storage tank.

Simplified Model for the Seismic Performance of Unanchored Liquid Storage Tanks

2015 ◽  
Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos
Keyword(s):  
Bottom Plate ◽  
Storage Tanks ◽  
Mass System ◽  
Aspect Ratios ◽  
Liquid Storage ◽  
Stress And Deformation ◽  
Cylindrical Tanks ◽  
Welded Connection ◽  
Simplified Modeling ◽  
Different Levels

Ground-supported unanchored liquid-storage cylindrical tanks, when subjected to strong seismic loading may exhibit uplifting of their bottom plate, which has significant effects on their dynamic behavior and strength. Those effects mainly concern: (a) the increase of axial (meridional) compression at the tank base, resulting in premature buckling in the form of elephant’s foot and (b) the significant plastic deformation at the vicinity of the welded connection between the tank shell and the bottom plate that may cause failure of the welded connection due to fracture and fatigue. The present study focuses on base uplifting mechanics and tank performance with respect to the shell/plate welded connection through a numerical two-step methodology: (1) a detailed finite element shell model of the tank for incremental static analysis, capable of describing the state of stress and deformation at different levels of loading and (2) a simplified modeling of the tank as a spring-mass system for dynamic analysis, enhanced by a nonlinear spring at its base to account for the effects of uplifting. Two cylindrical liquid storage tanks of different aspect ratios are modeled and analyzed in terms of local performance of the welded connection. The results are aimed at better understanding of tank uplifting mechanics and motivating possible amendments in existing seismic design provisions.

Saddle and Lug Supported Tanks and Vessels

1994 ◽  
Vol 208 (1) ◽  
pp. 17-21 ◽  
Author(s):  
V Křupka
Keyword(s):  
Plastic Deformation ◽  
Cyclic Loading ◽  
Brittle Fracture ◽  
Crack Growth ◽  
Carrying Capacity ◽  
Cyclic Load ◽  
Storage Tanks ◽  
Local Stresses ◽  
The Difference ◽  
Cylindrical Tanks

High stresses originate in the region of the support of circular cylindrical storage tanks and vessels. These influence the brittle fracture and crack growth by cyclic loading. The plastic deformation caused by the squeeze of the saddle into the vessel limits, in particular, the carrying capacity. Besides local stresses the effect of buckling is not negligible. The difference between the loose and welded support is discussed. Unstiffened and ring-stiffened circular cylindrical tanks are taken into consideration. Derived formulae enable the designer to take into account the effect of cyclic load, fatigue and buckling.

Nonlinear behaviour of bottom plate in cylindrical liquid storage tanks for seismic applications

1995 ◽  
Vol 22 (1) ◽  
pp. 180-189 ◽  
Author(s):  
David T. Lau ◽  
Xianguang Zeng
Keyword(s):  
Bottom Plate ◽  
Response Analysis ◽  
Beam Model ◽  
Nonlinear Behaviour ◽  
Storage Tanks ◽  
One Dimensional ◽  
Nonlinear Springs ◽  
Liquid Storage ◽  
Cylindrical Tanks ◽  
Seismic Applications

The paper presents a simplified pseudostatic approach to model the nonlinear behaviour of the bottom plate in unanchored cylindrical liquid storage tanks for seismic applications. In this paper, the problem of axisymmetric uplift of the bottom plate is studied for tanks supported on both rigid and elastic Winkler foundations. In the analysis, the bottom plate is modelled by one-dimensional beam and two-dimensional plate models. By comparing the results, it is found that the one-dimensional beam model gives accurate results acceptable for all practical design purposes, in view of the many other uncertainties in the tank uplift problem. The analysis results also show that the support foundation flexibility may have significant effects on the uplift behaviour of the tanks. Based on the axisymmetric uplift results, the paper then presents a simple approach to model the seismic partial uplift problem of unanchored tanks by means of nonlinear springs. Modelling parameters for the nonlinear springs are generated for dynamic uplift response analysis. Sensitivities of the uplift behaviour and the nonlinear spring modelling parameters to the tank height-to-radius ratio and the soil stiffness are also studied. Key words: axisymmetric uplift, cylindrical tanks, earthquakes, pressure vessel, shell, soil effect.

Seismic Design of Cylindrical and Spherical Storage Tanks According to API and Eurocode: A Difficult Merge in Design Philosophies

2003 ◽  
Author(s):  
Ch. Botsis ◽  
G. Anagnostides ◽  
N. Kokavesis
Keyword(s):  
Seismic Design ◽  
Structural Design ◽  
Bottom Plate ◽  
Design Codes ◽  
The European Union ◽  
Storage Tanks ◽  
Member States ◽  
The World ◽  
Design Requirements ◽  
Cylindrical Tanks

Herein a comprehensive review and comparison of the parameters used in design of cylindrical tanks according to API 650 and Eurocodes is presented. API 650 is extensively used in many countries, including Greece, for the design of storage tanks. The European Community has developed a set of structural design codes named Eurocodes. They are the gathering and combination of existing design knowledge of many member states. Some of these codes are already mandatory in many member states, whereas others are still under discussion and improvement. The design of storage tanks is covered in the last editions of Eurocodes. It was found that the seismic design according to Eurocodes is more conservative that of API 650. As compared to API 650, the thickness of the first, second, and third courses of storage tanks needs to be increased by 15% or 20% on average, when the seismic design requirements of Eurocodes is used. Similarly the thickness of the bottom plate under the first course, must also be increased to comply with the seismic design requirements of Eurocodes. Most likely Eurocodes will be mandatory in the European Union, and therefore it is important to study and discuss the main differences between API 650 and Eurocodes. Undoubtedly API 650 is a historic and well-tested code. It has been applied in the design of storage tanks all over the world, however compliance with local and European laws is required to issue an installation license.

scholarly journals Buckling of thin-walled cylinders: experimental and numerical investigation

2010 ◽  
pp. 47-52
Author(s):  
Caitríona de Paor
Keyword(s):  
Chemical Engineering ◽  
Oil And Gas ◽  
High Strength ◽  
External Pressure ◽  
Storage Tanks ◽  
Diverse Range ◽  
Thin Walled Structures ◽  
Liquid Storage ◽  
Thin Walled ◽  
Cylindrical Tanks

Thin-walled structures, also known as shells, combine light weight with high strength and are used in a diverse range of fields including aerospace engineering, civil engineering and chemical engineering. Common applications of these shells include oil and gas storage tanks, powder or liquid storage tanks in pharmaceutical plants as well as airplane frames and ship bodies. Although these thin-walled shells have a wide variety of uses, this research is motivated by storage tank collapse in the process industry. Thin-walled cylindrical tanks common in the food and biotechnology sectors are prone to buckling (or inward collapse) due to accidentally induced internal vacuum. During the sterilisation process, steam can condense, causing a reduction in volume. This results in an equivalent increase in external pressure, triggering collapse, or buckling of the tank. Such a collapse, if it occurs, tends to be catastrophic resulting in the complete destruction of the vessel (see Fig.1). Notwithstanding ...

scholarly journals APPLICATION OF THE NON-LINEAR FE MODELS TO ESTIMATE EFFECT OF SOFT DEFECTS ON THIN WALLS OF STEEL CYLINDRICAL TANKS

2006 ◽  
Vol 12 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Konstantin Rasiulis ◽  
Michail Samofalov ◽  
Antanas Šapalas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thin Wall ◽  
Storage Tanks ◽  
The Finite Element Method ◽  
Design Standards ◽  
Thin Walls ◽  
Cylindrical Tanks ◽  
Local Defects ◽  
Element Method

Steel storage tanks and other structures of such kind of buildings have been extensively designed following the requirements of continuous cyclic operations. Because of many economically based reasons any engineering inspections of a huge volume are very expensive, so numerical investigations of the local defects are practically important. Natural inspection of tank dents (volumes of tanks were from 1 000 to 50 000 m3, diameter of dents from 0,40 to 4,50 m, a depth up to 120 mm) has shown that analytical approach of their investigation by using existing design standards is rather complicated. The main objectives of the presented investigations are: to determine an appropriate size of the finite element for geometrical defect modelling on thin wall of the steel cylindrical tank; to identify stress/strain state by using finite element method in the place of the defect; to define the appropriate results of the proposed analytical solutions and requirements of the codes with FEM results. The results, derived from the proposed formulas, are compared to those of natural inspection of real tanks and also with the results obtained by numerical modelling using the finite element method.

Hydrodynamic experiments with rigid cylindrical tanks subjected to transient motions*

1951 ◽  
Vol 41 (4) ◽  
pp. 313-346
Author(s):  
Lydik S. Jacobsen ◽  
Robert S. Ayre
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Vertical Plane ◽  
Storage Tanks ◽  
Direction Parallel ◽  
Fluid Damping ◽  
Hydrodynamic Experiments ◽  
Wave Heights ◽  
Equivalent Mass ◽  
Cylindrical Tanks

Abstract Four tanks, from 6 inches to 4 feet in diameter, have been subjected simultaneously to transient, horizontal “ground motions” of simplified type. The important parameters, in addition to size of tank, were depth of fluid and frequency, duration, and amplitude of ground motion. The envelopes of the gravity-wave profiles have been recorded on a vertical plane of symmetry placed within each tank in a direction parallel to the ground motion. The data include samples of the wave envelopes, photographic studies of the wave formation, maximum wave heights and the locations of these maxima, and the fluid damping coefficients. Equivalent mass and overturning moment due to the fluid have been shown for various degrees of confinement of the upper surface, from complete confinement (owing to use of a rigid cover) to a free surface. The study relates to the effect of earthquakes and other ground motions on oil and water storage tanks. The results can be extrapolated with reasonable certainty to full-scale tanks.

Structural Effects of Foundation Tilt on Storage Tanks

1992 ◽  
Vol 206 (2) ◽  
pp. 83-92 ◽  
Author(s):  
S C Palmer
Keyword(s):  
Rational Design ◽  
Experimental Tests ◽  
Storage Tanks ◽  
Structural Effects ◽  
Bulk Storage ◽  
Simple Method ◽  
Current Design ◽  
Shear Buckling ◽  
Cylindrical Tanks ◽  
Liquefied Gas

Vertical cylindrical tanks for bulk storage of oil and liquefied gas are sometimes constructed on soils that are susceptible to settlement. The types of foundation settlement and their structural effects on the tank are reviewed. An arbitrary operational limit of 1 in 200 is sometimes quoted for the foundation tilt of atmospheric storage tanks. This limit is based on aesthetic considerations and on the effects on pipework connections and other attachments. Many tanks reach this limit before the end of their design life, and tank owners face difficulties in assessing the effects of foundation tilt since the current design and inspection codes give no guidance. The purpose of this paper is to present a simple method for calculating the overturning moment, shear force and associated stresses caused by tilt of a tank, and to present a rational design basis. The procedures can be used in the design of new tanks to withstand a specified magnitude of foundation tilt and also to predict the maximum allowable tilt for existing tanks. Similarities with the overturning effects caused by wind and seismic loading are identified. The possibilities of axial buckling and shear buckling are investigated, and allowable stresses are discussed. For anchored tanks, the effects of tilt on the shell hold-down anchors are shown to be significant, and for unanchored tanks the possibility of shell uplift is discussed. A diagrammatic representation of the results is presented which allows stresses caused by tilt to be compared with stresses caused by other tank loads and the prediction of stresses caused by future tilt. Experimental tests on a model open-top tank are reported, and indicate that tilt did not cause significant distortion of the tank.

scholarly journals Rectangular tank under the seismic load

2020 ◽  
Vol 313 ◽  
pp. 00022
Author(s):  
Norbert Jendželovský ◽  
Lenka Uhlířová
Keyword(s):  
Response Spectrum ◽  
Water Storage ◽  
Static Model ◽  
Seismic Load ◽  
Lower Sensitivity ◽  
Storage Tanks ◽  
The Finite Element Method ◽  
Rectangular Tank ◽  
Cylindrical Tanks ◽  
Over Time

Tanks have been currently used for the storage of various substances, in particular as drinking water storage tanks and for storage of various technical fluids. Rectangular tanks have advantages over cylindrical tanks, such as: lower sensitivity to unilateral loads and better use of space when used in a system of tanks. The rectangular tank analyzed in this article is filled with water. During the dynamic analysis of the tank, it was loaded by an accelerogram of a natural earthquake. In the calculation, the method of direct integration over time was used, considering damping. From the accelerogram a response spectrum was generated and applied as an additional loading of the tank. The static model of the tank was created in the ANSYS program, which works on the basis of the finite element method (FEM).

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