Liquid Storage Structures Research Articles

Seismic Response of Foundation Settlement for Liquid Storage Structure in Collapsible Loess Areas

To investigate the impact of foundation settlement in loess areas on the dynamic response of liquid storage structure (LSS) under seismic motion, a finite element analysis model of the liquid–solid coupling of LSS was established using ADINA V9.6 software. By analyzing the dynamic response patterns of LSS under seismic motion with foundation failure, this study examines the effects of foundation failure and the direction of seismic wave incidence on the equivalent stress, maximum shear stress, wall displacement, and liquid sloshing wave height of the structure. The results indicate that among the three foundation failure scenarios, foundation failure at the center of the tank bottom has the least impact on the structural dynamic response. In contrast, foundation failure affecting one-fourth of the tank base has the greatest impact. Furthermore, compared to seismic motion along the X-axis, the dynamic response of the structure is more significantly affected when seismic motion co-occurs along the X-Z-axis.

Enhancement of the structural behavior of elevated water tanks using X-plate dampers

This study aims at utilizing of X-plate dampers to effectively address vibrations and minimize the possible structural harm to water tank facilities, and also at utilizing a finite element methodology to simulate and analyze the structural reactions. A non-linear time history analysis is employed to assess the effectiveness of X-plate dampers when subjected to different blast-induced ground motions. The efficiency of dampers was evaluated by conducting a comparative analysis of liquid storage structures with and without dampers using 50 m3 and 1500 m3 tanks in empty and full conditions. X – plate dampers are installed in a variety of bracing schemes, such as diagonal, X, V, Inverted V, and K bracing subjected to underground blast loads to improve the resilience of the selected elevated water tanks. The results showed the X-bracing pattern is the most effective configuration for X-plate dampers in mitigating blast loads in a 50 m3 elevated tank without water, resulting in a reduction of displacement, shear force, and bending moment by 43%, 15%, and 22%, in case of elevated tank with water reduced by 39% 25% and 33% respectively. In 1500 m3 elevated tank without water, the K-bracing is determined to be the most effective type of bracing, reducing the displacement, shear force, and bending moment by 50%, 70%, and 70%, in case of elevated tank with water reduced by 53%, 52%, and 54% respectively. The current study makes a significant contribution to the field of structural engineering by providing useful insights into raised water tank construction.

Dynamic Response of Sand Cushion Layer Isolation Concrete Liquid Storage Structure with X-Type Soft Steel-SMA Shock Absorber Considering Long (Short) Period Earthquake

Dynamic Response of Sand Cushion Layer Isolation Concrete Liquid Storage Structure with X-Type Soft Steel-SMA Shock Absorber Considering Long (Short) Period Earthquake

Seismic Responses of Large Height-Width Ratio Liquid Storage Structure with Base Isolation and Baffles

Seismic Responses of Large Height-Width Ratio Liquid Storage Structure with Base Isolation and Baffles

Seismic Isolation Measures of Plate-Shell Integrated Concrete Liquid-Storage Structure

In order to study isolation measures for plate-shell integrated concrete liquid storage structure (PSICLSS), shaking table tests were carried out to investigate the seismic responses of PSICLSS. The isolation performance of rubber isolation and sliding isolation bearings for PSICLSS was studied and shape memory alloy (SMA) was used to reduce the residual displacement of sliding isolation PSICLSS. The results show that the sliding isolation bearing can effectively reduce the seismic response of PSICLSS; however, there is a large residual displacement in the isolation layer. On the other hand, SMA-sliding isolation can provide a reliable recentering capability for isolating PSICLSS and does not cause amplification of structural response.

On the dynamic response of rectangular liquid storage structure subjected to blast-induced ground shock

The paper aims to investigate the dynamic response of the rectangular liquid storage structure (LSS) under blast-induced ground shock. A two-way fluid–structure interaction (FSI) finite-element model was established, and its effectiveness was verified using a laboratory experiment conducted on an explosion shock and vibration simulation platform (ESVSP). The relationship between the mode shape and frequency was explored using modal analysis. Higher-order modes are characterised by more half-waves preferentially forming in the short sidewall and adjacent sidewalls vibrating in the same direction. The sensitivities of the deflection, hydrodynamic pressure, and equivalent strain in relation to the peak, duration, and loading direction of ground acceleration (i.e. PGA, TGA, and DGA) were highlighted. The results showed that the LSS response magnitude increases linearly as the PGA increases, whereas it first increases and then decreases as the TGA is extended. Furthermore, a feasible method for building a standard shock response spectrum (SRS) was proposed, in which the ground-shock effects were divided into mitigation, enhancement, and equality regions. It is beneficial to evaluate the extreme value of the LSS response to ground shock. The LSS vibration is dominated by different modes as the DGA is varied. The deformation mechanism was revealed by considering the boundary conditions and force characteristics. The conclusion indicates that the bottom middle of the sidewall, as a weak link, needs to be protected.

Seismic Failure Mechanism and Influencing Factors of Plate-Shell Integrated Concrete Liquid Storage Structure

To study the seismic failure mechanism of Plate-Shell Integrated Concrete Liquid Storage Structure (PSICLSS), the mechanical properties of each component under earthquake are studied. The influences of excitation frequency and amplitude on seismic responses of PSICLSS are analyzed. Based on the alternate load path method, the influences of partial component failure on the seismic responses of PSICLSS are studied, and the effects of free surface and structure size on seismic responses of PSICLSS are studied. Results show that the upper connection beams, upper plate and upper shell are easily tension failure. The effect of external liquid sloshing on the seismic response of the structure is more significant. The upper beams have a more significant influence on the structural seismic response. Considering the liquid free surface will cause structural stress increases. With the increase of the structural size, the structural stress, displacement and hydraulic pressure all increase, but the liquid sloshing height does not increase as the structural size increases.

Shaking table test of combination isolation plate-shell integrated concrete liquid-storage structure

To obtain the seismic performance of plate-shell integrated concrete liquid-storage structures (PSICLSS), a scale test model was built for shaking table testing. A combination isolation layer is proposed, and the dynamic responses of non-isolation and combination isolation PSICLSS under unidirectional and bidirectional earthquakes were tested. The results show that the combination isolation layer can change the spectral characteristics of the input acceleration, reducing the acceleration response and displacement of the structure, but it will increase the hydrodynamic pressure and liquid sloshing height. Under earthquake action, the liquid sloshing of combination isolation PSICLSS clearly appears as a nonlinear splash phenomenon. When considering the vertical earthquake, the horizontal acceleration response of PSICLSS and the liquid sloshing height change little, the peak hydrodynamic pressure changes significantly, and the peak position also changes. The maximum displacement of the isolation layer increases, but the residual displacement decreases.

Seismic characteristics of isolated plate-shell integrated concrete LSS

Plate-shell integrated concrete liquid-storage structure (PSICLSS) has been widely applied with the development of water treatment technology. However, there are few anti-seismic performance and base-isolation design researches on it. The seismic performance of PSICLSS was studied, and the accuracy of finite element analysis was verified by experimental study. A calculation method of damping coefficient is proposed and used in a PSICLSS study. Based on 5 natural accelerations and 2 artificial accelerations, the dynamic responses of the isolation liquid storage structure under different peak ground acceleration are analyzed. The analysis results show that, non-isolated PSICLSS is easy to damage when subject to earthquake. The principal stress of the structure is maximum at the upper beam, and the maximum liquid hydrodynamic pressure appears at the connection position of the upper and lower conical shell. When the base isolation measure is used, the stress of the structure can be effectively reduced, but the liquid sloshing response will be magnified. With the increase of peak ground acceleration, the structural dynamic response and liquid sloshing response will increase.

Pinch and exergy evaluation of a liquid nitrogen cryogenic energy storage structure using air separation unit, liquefaction hybrid process, and Kalina power cycle

Starting up thermal power plants for peak shaving is very time-consuming and expensive. Therefore, when the consumption demand is less than the baseload, the surplus energy that can be produced can be stored in a cryogenic energy manner, and in the hours of increasing demand, the stored energy can be injected into the consumption network as electrical energy. The main problems of liquid air energy storage systems are the high cost of development and low energy efficiency. In the present study, an integrated power generation system with liquid nitrogen recovery as a cryogenic energy storage system is developed. For this purpose, by producing pure nitrogen through air separation unit and liquefaction it during off-peak time and recovery it at the on-peak time, the required power of the grid is supplied. By using the excess heat of the integrated system in the Kalina power cycle and producing more power during the on-peak time, an attempt has been made to increase the system round-trip efficiency. Important parameters of the proposed system are the liquid yield (59.17%), multifunctional round-trip efficiency (40.67%), and baseline round-trip efficiency (54.69%). Pinch analysis is applied to the multi-stream exchangers of the system and the corresponding heat exchanger networks being extracted. The results of exergy analysis show that the exergy efficiencies of the nitrogen liquefaction unit and power generation unit are calculated as 79.75% and 85.11%, respectively. The exergy efficiency of the whole integrated system is 43.85%. The most exergy destruction belongs to the heat exchangers, which accounts for 48.56% of the total destruction. One of the important results of the parametric study is the increase of baseline round-trip efficiency to 57.24% by increasing the Kalina cycle pressure up to 1100 kPa.

Seismic responses and design recommendations for a plate-shell integrated concrete liquid-storage structure

The seismic capacity of a plate-shell integrated concrete liquid-storage structure (PSICLSS, a new type water treatment structure) is studied under different liquid storage conditions to obtain the most unfavorable liquid storage conditions and provide theoretical guidance for PSICLSS design and construction. In this paper, different liquid storage conditions are analyzed for the maximum displacements, principal stresses, hydraulic pressures and sloshing wave heights of liquids in the structure. The results show that different liquid storage conditions cause significant changes in PSICLSS responses. The principal stress caused by external liquid is larger than that caused by internal liquid and is maximum when both internal and external liquids are stored, close to the tensile strength of concrete. Different liquid storage conditions do not cause significant response changes in the hydraulic pressure and sloshing wave height of the liquid. The hydraulic pressure caused by internal water is higher than that caused by external liquid, but the sloshing wave height of external liquid is higher than that of internal liquid. Further, the structural and hydrodynamic response mechanisms caused by different peak accelerations are similar and only cause peak values to change significantly. Finally, some design and construction recommendations are proposed and applied to an actual project.

Simplified Analysis of Pure Conical Water Vessels Under Hydrostatic Loading

Liquid storage structures represent an important component of modern infrastructure. They can take variety of shapes of which the conical shape is one of the most common configurations. Conical tanks are preferred by both architects and structural engineers because of their appealing look and structural efficiency in addition to their large capacities with relatively small footprint area. The state of stresses in these tanks is rather complicated and needs powerful computational tools. However, in the preliminary design phase, it is important to have a simplified analysis method for selection of economic design parameters including tank height, inclination angle, and footprint radius needed to achieve the desired tank capacity. It is also of importance that the structural engineer has an insight and understanding of the effect of these various parameters on the resulting internal forces acting on the tank. This paper presents a simplified analysis of conical tanks under hydrostatic loading based on the application of the membrane theory. The equations governing the behavior of these structures are first derived. Then, they are applied on several vessels of practical dimensions and the resulting of stresses are presented to give a deeper understanding of the resulting internal actions. Moreover, a simple guide to achieve efficient structural preliminary design parameters for a wide range of tank capacities is introduced.

Mechanical properties of Q345 structural steel after artificial cooling from elevated temperatures

Water cannot be used to effectively extinguish fires that occur in chemical plants, oil and gas pipelines, and other flammable and combustible liquid storage structures. In such cases, firefighting foam is often used as a fire-extinguishing agent. In this study, we experimentally investigate the mechanical properties of Q345 steel after subjecting it to temperatures of 200–900 °C, followed by artificial cooling using water or firefighting foam. The fire-affected specimens are subjected to tensile tests to observe their fracture characteristics and obtain their stress–strain curves. Below an exposure temperature of 600 °C, the mechanical properties of Q345 steel remain almost entirely unchanged, irrespective of the cooling method. Above 600 °C, the mechanical properties of Q345 steel experience significant changes based on the exposure temperature and the type of cooling method. When Q345 steel is exposed to temperatures of 800 °C and 900 °C and cooled using water, its yield strength and ultimate strength increase significantly. In contrast, the ductility of the Q345 steel that is water cooled from temperatures of 600–900 °C rapidly decreases with the increase in temperature. When Q345 steel is exposed to temperatures of 600–900 °C and cooled using firefighting foam, it experiences a significant reduction in both yield strength and ultimate strength. In contrast, the ductility of Q345 steel that is cooled using firefighting foam does not change significantly. Subsequently, the macroscopic and microscopic fracture morphologies are also analyzed to better understand the changes in the mechanical properties of Q345 steel. Finally, empirical equations are proposed to predict the mechanical properties of fire-affected Q345 steel that is cooled using water or firefighting foam.

Seismic responses of concrete rectangular liquid storage structure with large height-width ratio

Concrete rectangular liquid storage structure (CRLSS) with a large height-width ratio has good application prospects due to saving land resources. 3-D Solid element and 3-D Fluid element are used to simulate structure and liquid; and free surface is set to simulate the liquid sloshing behavior. Based on potential flow theory, a three-dimensional numerical model for CRLSS with large height-width ratio is established by ADINA. Results show that wall tensile stress exceeds the concrete tensile strength 2.39 MPa when liquid level height reaches to 11.70 m. There are the optimal baffle positions which can ensure that the wall tensile stress is less than the concrete tensile strength when PGA is 0.22 g, and the wall tensile stress reaches the minimum value when the baffle height is 3.6 m. Opening size has little effect on the wall tensile stress, but it has a significant effect on the baffle tensile stress. Seismic capacity of CRLSS with large height-width ratio designed by using the optimal baffle position can meet the requirements when PGA is 0.22 g, and it is necessary to carry out further comprehensive damping measures when PGA reaches 0.62 g. The arrangement of horizontal baffle can provide an effective way for the engineering application of large height-width ratio CRLSS.

Seismic capacity evaluation of a sliding isolation concrete rectangular liquid-storage structure

Considering fluid-structure interaction (FSI), material nonlinearity and liquid sloshing nonlinearity, a nonlinear calculation model of sliding isolation concrete rectangular liquid-storage structure (CRLSS) with limiting devices is established. Failure criteria for sliding isolation CRLSS are summarised and defined, and a method for evaluating seismic capacity of sliding isolation CRLSS is proposed. Under near-field pulse-like earthquake, near-field no-pulse earthquake and far-field earthquake, seismic capacities of no-isolation structure, pure sliding isolation structure and sliding isolation structure are studied, comparatively. Results show that the seismic capacity of CRLSS is weakest under the actions of near-field pulse-like earthquakes; when the height of the reserved no-liquid wall is sufficiently large, sliding isolation can convert the main failure mode of the CRLSS from wall crack to excessive structure displacement, and the reasonable design of limiting device can reduce the failure probability of the sliding isolation CRLSS caused by excessive structure displacement. Besides, it is more reasonable to evaluate the seismic capacity of the system considering multiple failure criteria, and liquid level height and limiting device are the two important factors that affect the failure probability of the sliding isolation CRLSS.

Dynamic responses of base-isolated concrete liquid storage structure under two types of resonances

One important characteristic of base-isolated liquid storage structure (LSS) is that the vibration periods of structure and liquid are different, namely, there are two kinds of periods in the system. As a result, structure or liquid resonance may occurs under external excitation. In order to reflect the nonlinear characteristics of liquid sloshing, subsonic potential-based element is used to simulate the liquid. The governing equations of liquid field and fluid-structure interaction (FSI) equations are established; the initial and boundary conditions of liquid sloshing in dynamic coordinate system are obtained. Harmonic functions used to conduct time history analysis are generated by the first order vibration frequencies of structure and liquid respectively. The dynamic responses of base-isolated rectangular liquid storage structure (RLSS) under two types of resonance are studied comparatively. Results show that when the external excitation frequency is equal to the first order vibration frequency of isolated structure or liquid sloshing, wall tensile stress, structure displacement, base shear force and liquid sloshing wave height will appear resonance amplification phenomenon. The dynamic responses of structure itself caused by structure resonance are greater than that of liquid resonance; while the liquid sloshing wave height caused by liquid resonance is greater than that of structure resonance. Under structure resonance, the wall is prone to be cracked; and under liquid resonance, the liquid velocity field will become unusually violent, and liquid overflow will be caused easily.

Self-healing and leakage performance of cracks in the wall of a reinforced concrete water tank

A reinforced concrete water tank is a typical functional liquid storage structure and cracks are the greatest threat to the liquid storage structure. Tanks are readily cracked due to seismic activity, thereby leading to the leakage of the stored liquid and a loss of function. In order to study the effect of cracks on liquid storage tanks, self-healing and leakage tests for bending cracks and through cracks in the walls of a reinforced concrete water tank were conducted. Material performance tests were also performed. The self-healing performance of bending cracks in a lentic environment and through cracks in a lotic environment were tested, thereby the self-healing width of bending micro-cracks in the lentic environment in the short term were determined. The through cracks had the capacity for self-healing in the lotic environment was found. The leakage characteristics of the bending cracks and through cracks were tested with the actual water head on the crack. The effects on liquid leakage of the width of bending cracks, the depth of the compression zone, and the acting head were determined. The relationships between the leakage rate and time with the height of the water head were analyzed. Based on the tests, the relationships between the crack characteristics and self-healing as well as the leakage were obtained. Thereby the references for water tank structure design and grading earthquake damage were provided.

Cooperative inversion of magnetotelluric and seismic data on Shurab diapirs in Central Iran

Using diapirs as liquid or gas storage structures has increased because salt formations are considered to be extremely impermeable and non-reactive. The process of delineating the diapirs’ structures ends in lots of challenges due to their geological complexity. Therefore, the integration of different geophysical methods seems to be necessary to cover different physical characteristics of the diapirs. Shurab diapirs located at the NW of Kashan in Qom basin of Central Iran have been considered as candidates for the first natural gas storages in Iran. A previous 2D seismic survey across the diapir No. 4 of Shurab could not resolve the diapir structure properly and some ambiguities left unresolved. The main goal of this paper is to resolve the structure of diapir No. 4 by employing a cooperative inversion of the seismic and magnetotelluric (MT) data and a comparison with the joint inversion of transverse electric (TE) and transverse magnetic (TM) modes of the MT data. Both inversion schemes show the salt and sedimentary sequences of the stratigraphy of the Qom basin. The sequences of formations from the surface to depth are classified as upper red formation (URF), Qom formation (QF) and lower red formation (LRF). The results also show that the salt body has originated from the LRF. It is worthwhile to mention that the results from the cooperative inversion provide more details especially on the flanks and overhangs of the diapir No. 4. In addition, we have come to the conclusion that the right lateral strike-slip fault system is the most responsible phenomenon for the development of the diapirs in the survey area and the Sen–Sen fault plays a basic role as an elevator to pushing the salt up. The results are in good agreements with the resistivity and density logs of the boreholes. Moreover, the information from the geology, the cooperative inversion results on diapir No. 4, and the coincidence of the path of the Sen–Sen fault with the outcrops of the diapirs No. 1, 3 and 4 obviously provide that the tectonic scenario of the existence for diapir No. 4 could be appointed to the diapirs No. 1 and 3 equally. Another probable consequence would be the under surface continuation of the salt bodies all along the Sen–Sen fault, the verification of which requires regional MT surveys in a regular grid.

Pounding Dynamic Responses and Mitigation Measures of Sliding Base-isolated Concrete Rectangular Liquid Storage Structuress

This paper adopts a simplified spring-mass mechanical model for a concrete rectangular liquid-storage structure (CRLSS). Using a nonlinear model to simulate the pounding effect based on the contact element method, the effects of pounding and parameters on the dynamic responses of a CRLSS are studied. Mitigation measures for the pounding effect are investigated. The dynamic responses and the liquid sloshing height are increased after pounding. A parameter analysis shows that impact stiffness, initial gap, peak ground velocity, isolation period, liquid height and length-width ratio (LWR) of the structure are the main factors affecting the pounding response. Certain intermediate gaps can maximize the amplification caused by pounding. The coefficient of restitution (COR) can be reduced by installing a bumper layer, and the COR decreases with an increasing bumper thickness. A reasonable bumper design not only allows the moat wall to limit the displacement but also effectively reduces the structure’s dynamic responses and number of collisions caused by pounding.

Seismic reliability of concrete rectangular liquid-storage structures

To analyze the seismic reliability of concrete rectangular liquid storage structures (CRLSSs), assuming that the wall thickness and internal liquid depth of CRLSSs are random variables, calculation models of CRLSSs are established by using the Monte Carlo finite element method (FEM). The principal stresses of the over-ground and buried CRLSSs are calculated under three rare fortification intensities, and the failure probabilities of CRLSSs are obtained. The results show that the seismic reliability increases with the increase of wall thickness, whereas it decreases with the increase of liquid depth. Between the two random factors, the seismic reliability of CRLSSs is more sensitive to the change in wall thickness. Compared with the overground CRLSS, the buried CRLSS has better reliability.