scholarly journals Dynamic time-history response of concrete rectangular liquid storage tanks

Author(s):  
Amirreza Ghaemmaghami

In this study, the finite element method is used to investigate the seismic behaviour of concrete, open top rectangular liquid tanks in two and three-dimensional spaces. This method is capable of considering both impulsive and convective responses of liquid-tank system. The sloshing behaviour is simulated using linear free surface boundary conditions. Two different finite element models corresponding with shallow and tall tank configurations are studied under the effects of all components of earthquake record. The effect of earthquake frequency content on the seismic behaviour of fluid-rectangular tank system is investigated using four different seismic motions including Northridge, El-Centro, San-Fernando and San-Francisco earthquake records. These records are scaled in such a way that all horizontal peak ground accelerations are similar. Fluid-structure interaction effects on the dynamic response of fluid containers are taken into account incorporating wall flexibility. A simple model with viscous boundary is used to include deformable foundation effects as a linear medium. Six different soil types are considered. In addition the application of slat screens and baffles in reducing the sloshing height of liquid tank is investigated by carrying out a parametric study. The results show that the wall flexibility, fluid damping properties, earthquake frequency content and soil-structure interaction have a major effect on seismic behaviour of liquid tanks and should be considered in design criteria of tanks. The effect of vertical acceleration on the dynamic response of the liquid tanks is found to be less significant when horizontal and vertical ground motions are considered together. The results in this study are verified and compared with those obtained by numerical methods and other available methods in the literature.

2021 ◽  
Author(s):  
Amirreza Ghaemmaghami

In this study, the finite element method is used to investigate the seismic behaviour of concrete, open top rectangular liquid tanks in two and three-dimensional spaces. This method is capable of considering both impulsive and convective responses of liquid-tank system. The sloshing behaviour is simulated using linear free surface boundary conditions. Two different finite element models corresponding with shallow and tall tank configurations are studied under the effects of all components of earthquake record. The effect of earthquake frequency content on the seismic behaviour of fluid-rectangular tank system is investigated using four different seismic motions including Northridge, El-Centro, San-Fernando and San-Francisco earthquake records. These records are scaled in such a way that all horizontal peak ground accelerations are similar. Fluid-structure interaction effects on the dynamic response of fluid containers are taken into account incorporating wall flexibility. A simple model with viscous boundary is used to include deformable foundation effects as a linear medium. Six different soil types are considered. In addition the application of slat screens and baffles in reducing the sloshing height of liquid tank is investigated by carrying out a parametric study. The results show that the wall flexibility, fluid damping properties, earthquake frequency content and soil-structure interaction have a major effect on seismic behaviour of liquid tanks and should be considered in design criteria of tanks. The effect of vertical acceleration on the dynamic response of the liquid tanks is found to be less significant when horizontal and vertical ground motions are considered together. The results in this study are verified and compared with those obtained by numerical methods and other available methods in the literature.


2021 ◽  
Author(s):  
Mehdi Moslemi

In this study, the seismic performance of concrete ground-supported cylindrical as well as liquid-filled elevated water tanks supported on concrete shaft is evaluated using the finite element method. The effects of a wide spectrum of parameters such as liquid sloshing, tank wall flexibility, vertical ground acceleration, tank aspect ratio, base fixity, and earthquake frequency content on dynamic behaviour of such structures are examined. Furthermore, the adequacy of current practice in seismic analysis and design of liquid containing structures is investigated. A comprehensive parametric study covering a wide range of tank capacities and aspect ratios found in practice today is also carried out on elevated tanks. Two different innovative strategies to reduce the seismic response of elevated tanks are examined, in the first strategy the inclined cone angle of the lower portion of the vessel is increased while in the second strategy the supporting shaft structure is isolated either from the ground or the vessel mounted on top. The results of this study show that capability of the proposed finite element technique. Using this method, the major aspects in the fluid-structure interaction problems including wall flexibility, sloshing motion, damping properties of fluid domain, and the individual effects of impulsive and convective terms can be considered. The effects of tank wall flexibility, vertical ground acceleration, base fixity, and earthquake frequency content are found to be significant on the dynamic behaviour of liquid tanks. The parametric study indicates that the results can be utilized with high level of accuracy in seismic design applications for conical elevated tanks. This study further shows that increasing the cone angle of the vessel can result in a significant reduction in seismically induced forces of the tank, leading to an economical design of the shaft structure and the foundation system. It is also concluded that the application of passive control devices to conical elevated tanks offers a substantial benefit for the earthquake-resistant design of such structures.


2021 ◽  
Author(s):  
Mehdi Moslemi

In this study, the seismic performance of concrete ground-supported cylindrical as well as liquid-filled elevated water tanks supported on concrete shaft is evaluated using the finite element method. The effects of a wide spectrum of parameters such as liquid sloshing, tank wall flexibility, vertical ground acceleration, tank aspect ratio, base fixity, and earthquake frequency content on dynamic behaviour of such structures are examined. Furthermore, the adequacy of current practice in seismic analysis and design of liquid containing structures is investigated. A comprehensive parametric study covering a wide range of tank capacities and aspect ratios found in practice today is also carried out on elevated tanks. Two different innovative strategies to reduce the seismic response of elevated tanks are examined, in the first strategy the inclined cone angle of the lower portion of the vessel is increased while in the second strategy the supporting shaft structure is isolated either from the ground or the vessel mounted on top. The results of this study show that capability of the proposed finite element technique. Using this method, the major aspects in the fluid-structure interaction problems including wall flexibility, sloshing motion, damping properties of fluid domain, and the individual effects of impulsive and convective terms can be considered. The effects of tank wall flexibility, vertical ground acceleration, base fixity, and earthquake frequency content are found to be significant on the dynamic behaviour of liquid tanks. The parametric study indicates that the results can be utilized with high level of accuracy in seismic design applications for conical elevated tanks. This study further shows that increasing the cone angle of the vessel can result in a significant reduction in seismically induced forces of the tank, leading to an economical design of the shaft structure and the foundation system. It is also concluded that the application of passive control devices to conical elevated tanks offers a substantial benefit for the earthquake-resistant design of such structures.


2011 ◽  
Vol 2011 ◽  
pp. 1-23 ◽  
Author(s):  
Sanaz Mahmoudpour ◽  
Reza Attarnejad ◽  
Cambyse Behnia

Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite element method and scaled boundary finite element method is applied. Finite element method is used to analyze the structure, and scaled boundary finite element method is applied in the analysis of unbounded soil region. Due to analytical solution in the radial direction, the radiation condition is satisfied exactly. The material behavior of soil and structure is assumed to be linear. The soil region is considered as a homogeneous half-space. The analysis is performed in time domain. A computer program is prepared to analyze the soil-structure system. Comparing the results with those in literature shows the exactness and competency of the proposed method.


2014 ◽  
Vol 1061-1062 ◽  
pp. 767-770
Author(s):  
Fan Lei ◽  
Yu Lin Deng ◽  
Xiao Hua Zhao

It’s important to study the vibration characteristic of submarine pipelines under current for reducing the harmful vibration. Research on fluid-structure interaction of submarine pipeline under current was presented. The pressure and velocity distribution of flow field around pipe with different velocity of flow were studied by ANSYS finite element software. The results show that the pipe is under the action of drag force along the direction of flow. The drag force increases with the flow velocity.


2012 ◽  
Vol 12 (11) ◽  
pp. 3495-3505 ◽  
Author(s):  
E. Çelebi ◽  
F. Göktepe ◽  
N. Karahan

Abstract. The objective of this paper focuses primarily on the numerical approach based on two-dimensional (2-D) finite element method for analysis of the seismic response of infinite soil-structure interaction (SSI) system. This study is performed by a series of different scenarios that involved comprehensive parametric analyses including the effects of realistic material properties of the underlying soil on the structural response quantities. Viscous artificial boundaries, simulating the process of wave transmission along the truncated interface of the semi-infinite space, are adopted in the non-linear finite element formulation in the time domain along with Newmark's integration. The slenderness ratio of the superstructure and the local soil conditions as well as the characteristics of input excitations are important parameters for the numerical simulation in this research. The mechanical behavior of the underlying soil medium considered in this prediction model is simulated by an undrained elasto-plastic Mohr-Coulomb model under plane-strain conditions. To emphasize the important findings of this type of problems to civil engineers, systematic calculations with different controlling parameters are accomplished to evaluate directly the structural response of the vibrating soil-structure system. When the underlying soil becomes stiffer, the frequency content of the seismic motion has a major role in altering the seismic response. The sudden increase of the dynamic response is more pronounced for resonance case, when the frequency content of the seismic ground motion is close to that of the SSI system. The SSI effects under different seismic inputs are different for all considered soil conditions and structural types.


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