Steel Water Storage Tanks Research Articles

SEISMIC EVALUATION OF FLEXIBLE STEEL WATER STORAGE TANKS

Cylindrical steel liquid storage tanks are widely used for water supply and industrial chemicals. The seismic response of these tanks differs from buildings as it stores liquid with different hydrodynamic characteristics. Steel tanks can be exposed to severe damages during earthquakes such as elephant’s foot buckling, diamond shape buckling, roof damage and failure of anchor bolts. This research investigates the seismic behavior of flexible steel water storage tanks using an analytical method. A series of parametric analyses are conducted for a typical liquid storage tank with different geometry properties and soil conditions. The effects of storage tank height, wall thickness, and subsoil type are investigated and their effects on the seismic response of the tank are evaluated and discussed. The results indicate that the soil type (representing shear wave velocity and shear modulus of the soil) has a profound impact on the base shear, overturning moment and hoop stress in the flexible tanks.

Seismic Analysis of Steel Tanks Subjected to Transitional-Rotational Components of Earthquakes

ABSTRACT In this study, the response of the steel water storage tank considering the water-structure interaction under the effects of the transitional and rotational components of the earthquake as well as the soil-structure interaction was evaluated using the Eulerian-Lagrangian method. Seismic loading consisted of rotational and transitional components of the earthquake. Rotational components of the earthquake were first obtained using the transitional components. Then, the seismic analysis of the tanks considering four different tank models with empty and 90% full reservoirs and five different foundation models with and without considering the rotational components was done. Foundation flexibility and its effect on the structure performance were addressed by changing the foundation stiffness from the rigid to the very soft one. Water-structure interaction was considered in the analysis taking into account the fluid compressibility and the energy absorption boundaries. Results showed that in most cases by applying the rotational components, the maximum displacements and shear stress decreased. Maximum displacement reduction values for tanks with height to radius ratios of 0.4, 1, 2, and 3 for empty tanks are 51.62, 32.32, 24.0, and 23.79, respectively, and tanks with 90% full are 49.42, 42.86, 28.88, 26.74, respectively. Also, principle stress decreased in most cases, and in few cases, an increase was observed. This decrease in shear stress was far higher for empty reservoirs than full reservoirs. By increasing the tank height, reducing effects of the rotational components in the seismic response of the tanks reduced, and the structural responses with and without applying the rotational components got close to each other. Results also showed that the rotational components have a significant effect on the structural response in terms of changing the location of the maximum responses in whole cases as well as increasing the maximum response in a few cases.

Seismic Fragility Assessment of Base-Isolated Steel Water Storage Tank

Steel water storage tanks (WSTs) are among the important components of water treatment industry facilities that are expected to remain functional and applicable after strong earthquakes. In this study, the seismic vulnerability of base-isolated steel WST is investigated. A three-dimensional finite element stick model of the targeted tank is created using OpenSees. This model is capable of reproducing convective, impulsive, and rigid responses of fluid-tank systems. Time-history responses of convective displacement, bearing displacement, and base shear force for base-isolated tank subjected to a typical ground motion are compared. Furthermore, time-history analysis based on a suite of 80 ground motions is conducted. The seismic demand models for various responses are established and the most efficient intensity measure (IM) is determined based on the dispersion and coefficient of determination. Seismic fragility curves for different responses are derived for all three damage states using cloud analysis. The results from this study reveal that (i) the convective displacement is significantly greater than bearing displacement; (ii) peak ground displacement (PGD) is the most efficient and sufficient IM for the targeted tank; and (iii) the characteristic of isolation bearing significantly influences the seismic fragilities of convective displacement and bearing displacement and has a little impact on base shear force, which makes the selection of the proper characteristic parameters for isolation bearing very essential. The analysis technique and procedure mentioned above as well as derived insights are of significance to general liquid storage tank system configuration.

On the modal response of an instrumented steel water-storage tank including soil-structure interaction

The modal response of liquid-storage steel tanks and the associated prevailing frequencies in the horizontal impulsive mode of vibration are explored by means of earthquake recordings. To this end, a well-documented case study is employed, referring to an instrumented steel cylindrical tank which is a property of the HEL.PE. Oil Company in the Kalochori area, west of Thessaloniki in Northern Greece. The 28.5m-diameter tank has a self-supporting dome roof fixed to the tank walls and it is partially filled with water, corresponding to a ratio of the liquid free surface height to the tank's radius (H/R) at 0.74. Two accelerometric stations are mounted close to the center of the tank roof and on the ground surface at free-field conditions. Seventy four (74) acceleration records from low-intensity earthquake motions are processed to identify the fundamental frequencies of the tank and of the foundation soil from pertinent transfer functions in the frequency domain. The experimental findings are compared with predictions from theoretical formulae recommended by seismic design codes for fixed-base and flexibly-supported tanks, thus allowing the assessment of soil-structure interaction effects on the fundamental period of the tank. A simplified three-dimensional finite-element model of the fluid-tank system resting on flexible supports is also analyzed to provide further insight on the recorded response, as affected by critical structural features of the tank. Results highlight a dominant rigid-body mode which is associated to the lateral fundamental period of the flexibly-supported system, in agreement with relevant code provisions for tanks with H/R below unity.

Dynamic buckling analysis of cylindrical steel water storage tanks subjected to Kobe earthquake loading

AbstractCylindrical steel storage tanks are thin‐walled significant engineering structures. This study investigated the buckling conditions of ground‐supported cylindrical steel liquid storage tanks according to roof shapes and shell thicknesses. The roof shapes selected were open‐top, flat‐closed, conical‐closed and torispherical‐closed‐top tanks, and shell thicknesses were 4, 6 and 8 mm. These tanks may be exposed to several types of failure during earthquakes, such as elephant‐foot buckling, diamond‐shape buckling, overturning and uplift. Great financial loss and environmental damage can also ensue when steel liquid storage tanks are damaged in an earthquake. The seismic analyses were conducted under Kobe earthquake conditions for cylindrical steel tanks with different shell thicknesses and roof types. To investigate dynamic behaviour of the tanks accurately, the hydrodynamic response of each tank was divided into impulsive and convective components. Directional deformation and buckling results are presented for both impulsive and convective masses. As a result, the deformation of the tank is significantly reduced when the top of the tank is in the shape of a torispherical dome. The flat‐closed tank has a maximum directional deformation in both impulsive and convective modes. Results also show that when shell thickness was increased, buckling deformation decreased, but different deformation states were observed on the wall and roof components depending on the type of roof.

Corrosion of stainless steel water storage tanks exposed in coastal atmospheric conditions

Results of corrosion survey for stainless steel tanks used in water storage at various coastal areas are presented. Corrosion damages were revealed at both the outer and inner surfaces of tanks made of 304 and 201 steel grades. Corrosion deterioration was more severely observed for the atmospheric areas with higher airborne salinity and time of wetness. Corrosion products examined by visual inspection and SEM-EDX technique show relatively distinctive characteristics for outer and inner surfaces which are attributed to different mechanisms of corrosion initiated by various corrosive agents in the atmosphere. Atmospheric chlorides from airborne sources are considered the main reason for causing corrosion of 304 and 201 steel grade water tanks.

DESIGN OF LIQUID-STORAGE TANK: RESULTS OF SOFTWARE MODELING VS CALCULATIONS ACCORDING TO EUROCODE

The objective of this article is to show the design process of a liquid-storage tank shell according to Eurocode and compare the results obtained using the norms with those from a finite element method (FEM) analysis. The calculations were performed for an aboveground vertical steel water-storage tank with a variable thickness wall and stiffening ring on top. First, the types of liquid storage tanks are briefly explained. Second, the given tank is described. Third, an analysis of the tank wall according to the Eurocode was carried out. The FEM analysis was performed using the Scia Engineer ver. 17 software. Finally, all the results are presented in tables and compared.

Dynamic analysis of liquid storage tank under blast using coupled Euler–Lagrange formulation

A growing number of terror attacks all over the world have become a threat to the human civilization. In the last two decades, bomb blasts in crowded business areas, underground railway stations and busy roads have taken numerous lives and destroyed properties in different parts of the world. However, blast response of many important civil infrastructures has still not been well understood due to the complexities in their material behavior, loading and higher nonlinearities. One such example of important civil infrastructure is liquid storage tanks which are undividable parts of any society for storage of water, milk, liquid petroleum, chemicals in industries etc. Blast loading on liquid storage structures may lead to disaster due to water and milk crisis, health hazard owing to the spread of chemicals and fire hazard due to the spread of liquid fuel. Hence, understanding the dynamic behavior of liquid storage structures under blast loading through numerical simulations is of utmost importance. In the present study, three dimensional (3D) finite element (FE) simulations of a steel water storage tank for different tank aspect ratios, percentages of water stored in the tank, tank wall thicknesses, boundary conditions at the bottom of the tank and magnitudes of blast loading have been performed using the FE software Abaqus. The coupled Euler–Lagrange (CEL) formulation in Abaqus has been adopted herein which has the advantage of considering the coupling of structural mechanics and fluid mechanics fundamental equations. The maximum hoop stress and shear stress in the tank wall, the water sloshing heights in tanks and the energy response of the tanks have been studied. It is observed that stresses and liquid sloshing heights in the tank increase with decreasing scaled distance of the explosive material and increasing aspect ratio, i.e. height to radius ratio.

An Integrated Collector Storage Solar Water Heater and Study of its Temperature Stratification

In this paper we describe an integrated collector storage solar water heater for the North Western region of India for use as domestic water heater during the winter season and present the experimental results of temperature stratification. The system consists of a steel water storage tank with azimuthal orientation such that its walls face south east, south west, north east and North West directions. The sunlit walls (south east and south west) and the top cover surface of the storage tank are covered with transparent insulation material (TIM) and the off-sunlit sides with opaque insulation. Experimental results show that the top layer is at the highest temperature. The top layer is drained using a new design of the outlet. The system can be used in rural areas or as a pre heater in more affluent households. The system can return the cost of conversion of the storage tank into a Solar Water Heater in one winter season by saving the cost of electrical energy required for heating water during winter months.

Cathodic Protection Extends Storage Tank Life

By pairing protective coatings and cathodic protection, it's now possible to extend the life of a typical steel water storage tank's coating system for immersion service by as much as 20 years. Without cathodic protection, system failure of some sort is likely to occur within 10 years. This article discusses six key areas where the most significant advances in cathodic protection technology have occurred. AWWA and NACE International have both adopted corrosion‐control standards.

Crack Down on Water Tank Foundation Problems

This article discusses how to determine if cracks in the foundation of concrete storage tanks are superficial or are a real structural problem. The article describes the city of Virginia Beach, Virginia's experience with alkali silica reaction (ASR) on the deteriorating concrete pile caps of the tank foundations, discusses how the city investigated and evaluated the damage, and the repairs that were required. The article provides an inset of information from AWWA Manual M42, Steel Water Storage Tanks, that indicates who should be responsible for storage tank foundation design.

How Do We Keep Tank Water Fresh?

This month's column answers questions on operation and maintenance of finished water storage tanks. The article cites the AWWA Manual of Practice, Steel Water Storage Tanks (M42), as recommending that storage facilities need to be taken out of service, cleaned, inspected, and disinfected prior to return to service at least once every three years. The article addresses tank turnover, citing an AwwaRF report, Guidance Manual for Maintaining Distribution System Water Quality, as recommending a 2.5‐day turnover rate, which is equal to a 40% turnover per day. The article also addresses the change in pressure in the system when the tank water level fluctuates, citing several sources that agree on the general rule that every 2.31‐ft. change is equal to a 1‐psi change in the system.

Top Ten Steel Storage Tank Tasks to Tackle

This article describes the ten most important things to know to avoid potential problems when designing, erecting, demolishing, or rehabilitating your steel water storage tanks.

NEWS OF THE FIELD

The oldest steel water storage tank in service in the United States is in Baraboo, Wisconsin. Research has verified that the tank is 102 years old; it was constructed in 1886 and went into service in 1887. The runner‐up in steel tank longevity is the 170,000‐gal elevated storage tank in Whitewater, Wisconsin put into service in 1889. The water system of Baraboo is described.

Proper Maintenance Makes Tanks Last Longer

Steel water storage tanks that are properly maintained can remain useful for decades. Maintenance is often performed on a regular basis, whether it is needed or not. In other instances, maintenance is performed only when a municipal board of directors or utility manager is warned by a maintenance contractor os imminent tank failure. Most of those who could climb have neither the experience nor technical background to know what to look for once they get to the top of the tank. To correct these problems, a professional approach to tank maintenance was developed. This approach, which has proven to be very successful, is discussed in this article.

Interior Painting of Steel Water Storage Tanks

This article discusses a three‐way cooperative test that was instrumental in the Ambridge Water Authority adopting a more effective paint system (SSPC‐Paint System No. 4.00, vinyl paint system over sand‐blasted steel). It has been conservatively estimated that this system has increased the average trouble‐free life of paint on the interior of water tanks from 3 to more than 8 years, with a 50 per cent savings in annual painting costs.

Coatings for Steel Water Storage Tanks

This article begins by providing a brief overview of coatings for inside surfaces of steel water storage tanks, including various inside coating materials that have been extensively used. Topics covered include: toxicity; red‐lead phenolic paint; tar and asphalt coatings; wax coatings; newer coatings; vinyl paints; epoxy resins; outside coatings; colored paints; surface preparation; pickling and blast cleaning; cleaning and painting costs; and, maintenance and inspections.

Tentative Recommended Practice for Painting and Repainting Elevated Steel Water Storage Tanks, Standpipes, and Reservoirs

<i>Tentative Recommended Practice for</i> Painting and Repainting Elevated Steel Water Storage Tanks, Standpipes, and Reservoirs

Tentative Recommended Practice for Inspecting, Repairing and Repainting Elevated Steel Water Storage Tanks, Standpipes and Reservoirs

Journal AWWAVolume 40, Issue 10 p. 1101-1117 Article Tentative Recommended Practice for Inspecting, Repairing and Repainting Elevated Steel Water Storage Tanks, Standpipes and Reservoirs First published: 01 October 1948 https://doi.org/10.1002/j.1551-8833.1948.tb15058.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume40, Issue10October 1948Pages 1101-1117 RelatedInformation