DOT Applicable Regulations
Part 195.432 “Each operator must inspect the physical integrity of in-service atmospheric and low-pressure steelaboveground breakout tanks according to API Standard 653 (incorporated by reference, see §195.3). However, if structural conditions prevent access to the tank bottom, the bottom integrity may be assessed according to a plan included in the operations and
6.1.2 u If 5% or more of any 12 inch by 12 inches square area of the tank has a remaining wall thickness less than or equal to 50% of the original
thickness, remove the tank from service and contact a qualified tank manufacturer to have these sections repaired. These sections must be repaired by cutting out these sections and replacing them with new steel of the original design thickness or else by welding new steel of the original design thickness over the damaged areas. These repairs must be made from the side that is corroded. Have the qualified inspector re-inspect the tank after the repairs have been made. Identify and correct the cause of corrosion. Re-inspect the tank in 5 years, or less as recommended by the qualified tank inspector.
three translational components and three rotational components; translational components include two components in the horizontal plane, and one in the vertical direction. Rotation about horizontal axes leads to rising of rocking, while the rotational component about a vertical axis generates torsional effects even in symmetrical buildings. Due to evident and significant contribution of ground shakings to the overall response of structures, rocking and torsional components of these motions resulted by strong earthquakes are recently subjected to widespread researches by engineering and research communities. In this study, first rotational components of ground motion are determined using a method developed by Hong-Nan Li and et al (2004). This method is based on frequency dependence on the angle of incidence and the wave velocity. In consequence, abovegroundstoragetanks with different water elevations have been analyzed with the effects of these six components of earthquake. Three translational components of six important earthquakes have been adopted to generate relevant rotational components based on SV and SH wave incidence by the Fast Fourier Transform (FFT) with the discrete frequencies of time histories of translational motion. Using finite element method, linear properties of tank material including steel for cylindrical tanks have been taken into with considering fluid- structure interaction. Numerical linear dynamic analysis of these structures considering six components of earthquake motions is presented; results are compared with cases in which three translational components are considered.
The Steel Tank Institute (STI), formed in 1916, is a not-for-profit organization whose purpose is to secure co-operative action in advancing by all lawful means the common purposes of its members and to promote activities designed to enable the industry to conduct itself with the greatest economy and efficiency. It is further the purpose of STI to cooperate with other industries, organizations and government bodies in the development of reliable standards which advance industry manufacturing techniques to solve market- related problems.
Large capacity tanks and vessels are one such device which is assessed in terms of vulnerability against seismic effects. Tank-liquid systems are commonly used in the storage of various liquids in various sectors of industry (e.g., nuclear, chemical, food, etc.). Seismic analysis of liquid storagetanks requires special considerations which take into account time- dependent hydrodynamic forces and pressure exerted by the liquid on the tank wall and bottom. Knowledge of these hydrodynamic effects is essential in the seismic design of tanks. Inadequately designed tanks in the past exposed to strong ground motions led to damage, ruptures and failures of tank accessories. Furthermore, when tanks store flammable or toxic liquids, disastrous effects, such as uncontrolled fire, explosion or toxic dispersion arose . Therefore, tanks must be designed to maintain their integrity before, during and after a seismic event to prevent negative future effects.
The two tanks included in this study have steel plate walls with flexible flat bottoms and flexible floating roofs. The first tank (Tank 1) has a diameter of 92.3 meters, a wall height of 21.4 meters and a maximum fluid height of 20.0 meters. Its foundation consists of a reinforced concrete ring. The second tank (Tank 2) has a diameter of 60.5 meters, a wall height of 19.8 meters and a maximum fluid height of 18.0 meters. Its foundation consists of a reinforced concrete pad on piles.
In the test carried out on A36 steel, yield strength value for non-corroded steel was determined as 368 MPa (3750 kg/cm 2 ), the theoretical value for such stress is 345 MPa (3500 kg/cm 2 ) and the value determined in test for corroded steel is 312 MPa (3181 kg/cm 2 ). It was determined that steel lost 15.5% stress yield strength, as shown in Figure 10. The structural element designed with such steel is the false bottom support for filtering material inside the steel tank. Such element is an “I” profile with plate, including the false bottom plate as higher skid. Such type of profile is more sensible to plate thickness loss due to corrosion.
Cylindrical liquid storagetanks are contemplated as vital structures in industrial complex whose nonlinear dynamic behavior is of crucial importance. Some of these structures around the world have demonstrated poor seismic behavior over the last few decades; consonantly a major improvement is required to reach their level of applicability. There are several methods and techniques for rehabilitation and reducing damages in these structures which among them the devices for passive control, particularly base isolators, are perceptible. Friction Pendulum System (FPS) is the most popular base isolation system which its period does not depend on the structural weight. In this research work, the efficiency of FPS is examined on decreasing the seismic responses of base isolated steelstoragetanks as well as the impact effect of slider to the side restrainer. To this end, the whole mass of liquid storage tank is contemplated as three lumped masses known as convective mass, impulsive mass which is connected to tanks with corresponding spring, and rigid mass which is connected rigidly. By means of state space method the time history analysis is done applying 60 earthquake records to acquire dynamic responses under the various hazard levels i.e. SLE, DBE and MCE ground motions. The results show that the normalized base shear force in squat tank decreased 59%, 62% and 33% respectively under SLE, DBE and MCE ground motions. The reduction of normalized base shear force in slender tank is 53%, 49% and 35% under the aforementioned hazard levels. Examining the effect of side restrainer’s stiffness on the maximum responses exhibit that the impact effect must be considered particularly when the system is excited by MCE’s ground motions.
The experimental part of the study was also performed by a graduate student at North Carolina State University, and was entitled “Test of an Earth-Coupled Heat Pump With Aboveground Water Storage”. This study compared the results of the geothermal heat pump system to the results of a nearly identical air source heat pump on an adjacent classroom. The results of this study showed that the heat pump did use about one-half as much electricity as the air-source heat pump while in heating mode. However, in the cooling mode, the geothermal heat pump actually used about 80% as much energy as the air-source heat pump. Subsequent study showed that the ventilation rate in the classroom with the air source heat pump was well below the value recommended by ASHRAE. This changed the building load in favor of the air source heat pump.
An aim in the meshing was to obtain well proportioned elements, and mesh variations were made to ensure a converged solution. The meshing for uncovered tanks was with four-node 20 degree-of-freedom plate/shell elements. For covered tanks some triangular elements were used in the roof. In the circumferential direction, elements of equal size were selected, whereas in the axial direction scaling of element size by a ratio of one to three from bottom to top was undertaken. The small elements at the bottom were desirable to better represent the expected EFB in the collapse analysis. As symmetry exists, the majority of the meshes were for half-tank models, to reduce the computational effort. For some cases of analysis full-tank models were also conducted to demonstrate the validity of the half-tank models. The mesh sizes used are indicated in the following for some sample cases.
Impressed Current - An impressed current system uses an external DC power source,
usually a rectifier, to artificially impress anodes with electric current that then flows to the tank bottom. An impressed current system has the advantages of being able to produce the large driving electrical potential and high electric current output that are needed to satisfactorily protect large diameter tank bottoms. Electric current can also be increased or decreased as any variation in need occurs. Impressed current systems generally require a higher capital investment and maintenance level than sacrificial anode systems for small tanks, but cost less for larger tanks. Several different designs of impressed current systems are possible. The particular design that is selected often depends on the soil profile and the surrounding structures.
Methodologies such as one as discussed in O'Rourke and Pak (2000) can be used to develop storage tank seismic fragility curves. A fragility curve describes the probability of various levels of component damage as a function of measure of the seismic hazard, e.g., peak ground motion (PGA). Damage states are used to characterize component damage.Storage tanks on the path of tornado can be directly impacted by a tornado and the consequence can be overturning of the tanks, rupture of the pipe connections to the tanks, or collapse of the storagetanks in seismically active regions, or combination of these consequences. Furthermore, the tornado may impact the storage tank terminal by tornado-induced debris impact which may result in collapse and release of storage tank’s content.The appropriate secondary containment must be designed to address the quantity of oil that may be discharged from the tank failure, quantity of liquid from fire-fighting activities, and quantity of liquid from a 1-in-10 year and 1-in-100 year 24-hour rain precipitation events. Series of events potentially leading to a secondary containment overfill are identified. Probability of multiple storage tank rupture in a single shared secondary containment is considered in the calculation for structural behavior demonstration.
• containment of fire-fighting agents
• dynamic factors such as overtopping caused by surge and wave action following tank failure • an allowance for rainwater in the bund.
Construction Industry Research and Information Association (CIRIA) research (Reference 12) involving tanks of 25m 3 or less suggests that the 10% safety margin is inadequate in some circumstances to provide protection from loss of oil due to these factors. This research provides an alternative method for calculating bund capacity and height, and introduces the concept of the ’freeboard‘. The freeboard is the height of bund wall standing above the level of oil retained within the bund. See Appendix B for further details.
medians along elevation gradients, and these patterns differed in the N and S regions. In the north, the low- lands (< 1050 m) harbored a highly skewed distribution of carbon storage, resulting from human-driven forest losses leading to low carbon levels; yet with a sufficiently large, high-resolution regional sample size, we also found that ACD can reach very high values in surviving lowland forests. In effect, the right side of the distribu- tion indicates maximum potential carbon stocks in the lowlands, which exceeded 200 Mg C ha -1 . In contrast to N lowland carbon values, the S region harbored very suppressed ACD levels (Figure 4), and this was due to the drier conditions that support lower-biomass spiny forests as well as extremely high forest loss rates.
The methodology followed in the CST evaluation consists of generating stick models for the SSI analysis, obtaining response accelerations on the sticks and applying inertial loads computed from the response accelerations on a detailed FEM of the tank using the computer program GT-STRUDL (Ref. 5). Similar to the RMWT, the stick model representation of the CST captures 1) the horizontal impulsive mode, 2) the horizontal convective (sloshing) mode and, 3) the vertical mode. The dynamic characteristics of each mode are computed using the methodology provided in ACI 350 (Ref. 2), which is a standard methodology for concrete liquid storagetanks.
This study involves the filling automation and dosing control of a sulfuric acid storage tank with a capacity of 20000 liters. The filling control to carry out the reaction of sulfuric acid with bauxite more precisely avoiding risks and accidents to workers is proposed. To achieve this, a system that uses a flow sensor, a transmitter, and a PLC (Programmable Logic Controller) which performs the control actions on the solenoid valves and the centrifugal pump has been designed and implemented. Also, an HMI (Human Machine Interface) that allows the operator to manipulate and interact with the system to perform storage and dosing operations automatically or manually is performed. As a result of this work, a system in which the operator can store and dose sulfuric acid automatically or manually from the operating panel safely is achieved.
Stone columns in compressive loads fail in three main different modes: bulging  and general shear failure , punching in short columns and bulging in long columns . Therefore to investigate bulging and settlement characteristics of stone columns beneath the tanks, analysis was carried out. From fig 3 (a) shows that interior stone columns experiences less lateral deformation than exterior stone columns and is mainly due to higher confining pressure. This is in agreement with different previous research works on group of stone columns , . Lateral deformation of exterior stone columns is about 8 times more than interior stone columns. Whereas when settlement behavior of stone column under storage tank was considered, settlement of stone columns decreases with radial distance from centre of tank. In other words, centre columns experienced more settlement than columns at edge and is as shown in fig 3 (b).
There are a number of large cylindrical tanks containing water at nuclear power plants (NPPs). Condensate storagetanks (CSTs) are of particular concern for assuring the safe shutdown of an NPP in an accident and thus are classified as safety-related components requiring high confidence of a low probability of failure in a design-basis seismic event. CSTs store and provide cooling water used during normal NPP operation and in accidents for the removal of decay heat. The failure of CST may result in severe core damage due to the inability to remove decay heat from the primary system. Thus, an appropriate structural model for probabilistic risk assessment (PRA) analysis is required to evaluate risks associated with CSTs in NPPs (Sezen et al., 2015; Hur et al., 2016a). Seismic evaluation of CSTs is complicated due several issues, such as the dynamic fluid-structure interaction (FSI) between tank shell and fluid inside, sloshing motion of free surface vibration, capacity to resist buckling likely to occur on the tank body and other failure modes triggered by excessive hydrodynamic pressure of the fluid. Under some specific conditions such as buckling, the wall of the CST can be deformed sufficiently to display nonlinear inelastic behavior (Hur et. al., 2016b).
Storagetanks are essential part in industry in oil & gas fields. They are mainly used to store different fluid products such as water, oil and gas. To transport fluids from places of production to end users, we need storagetanks to store the products. Storagetanks were a key factor of the development of dozens of industries. Petrochemicals industry is a good example for the importance of storagetanks as it couldn’t be developed without the ability to store huge amount of crude and refined oils products in a safe and economic storages. Another example of the usages of storages tanks are the processing plants such as chemicals factory and food processing factories; since production pauses are always occur to allow reactions at different stages. Also, after ending the production process, we need safe and huge storages as the products cannot transport immediate to the customers and end users. The majority of the storagetanks are working under atmospheric pressure. According to API 620  the maximum allowable pressure for storagetanks is 15 psi and if the pressure is larger than this value, it is considered as a pressure vessel.