A coupled BE–FE–BE study for investigating the effect of earthquake frequency content and predominant period on seismic behavior of base-isolated concrete rectangular liquid tanks

2018 ◽  
Vol 77 ◽  
pp. 19-35 ◽  
Author(s):  
Mohammad Reza Shekari
Keyword(s):  
Seismic Behavior ◽  
Frequency Content ◽  
Predominant Period ◽  
Earthquake Frequency

Seismic analysis of a system of dam-massed foundation-reservoir under inclined excitation

2021 ◽  
pp. 107754632110005
Author(s):  
Payam Sotoudeh ◽  
Mohsen Ghaemian
Keyword(s):  
Seismic Analysis ◽  
Engineering Practice ◽  
Frequency Content ◽  
Earthquake Excitation ◽  
Concrete Dam ◽  
High Frequencies ◽  
Inhomogeneous Waves ◽  
Earthquake Frequency ◽  
Vertical Propagation ◽  
Massed Foundation

One of the acceptable assumptions in engineering practice is vertical propagation of earthquake waves. When the source of earthquake is located very deep in the ground, this assumption is valid, but for sources located in shallow ground, it loses its viability. In this study, linear seismic analysis of a system of concrete dam-massed foundation-reservoir is performed under inclined earthquake excitation. Both P- and SV-type earthquakes are considered for the purpose of the seismic analysis. To consider the effects of inhomogeneous waves for the case of SV wave propagation, post-critical angles are also considered in the analysis. To investigate the effects of earthquake frequency content on the results, three different records with contents of low, intermediate, and high frequencies are selected. Results indicate that considering vertical propagation underestimates the obtained responses. For the case of SV-type earthquakes, post-critical angles must be looked at. Frequency content of the earthquake also has considerable effects on trend and absolute values of responses.

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

2021 ◽  
Author(s):  
Amirreza Ghaemmaghami
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Vertical Acceleration ◽  
Surface Boundary ◽  
Frequency Content ◽  
Seismic Behaviour ◽  
Structure Interaction ◽  
Earthquake Frequency ◽  
Wall Flexibility ◽  
Tank System

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.

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

2021 ◽  
Author(s):  
Amirreza Ghaemmaghami
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Vertical Acceleration ◽  
Surface Boundary ◽  
Frequency Content ◽  
Seismic Behaviour ◽  
Structure Interaction ◽  
Earthquake Frequency ◽  
Wall Flexibility ◽  
Tank System

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.

scholarly journals Seismic Response of Ground Cylindrical and Elevated Conical Reinforced Concrete Tanks

2021 ◽  
Author(s):  
Mehdi Moslemi
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Cone Angle ◽  
Tank Wall ◽  
Frequency Content ◽  
Ground Acceleration ◽  
Earthquake Frequency ◽  
Wall Flexibility ◽  
Elevated Tanks ◽  
Vertical Ground

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.

Influence of earthquake frequency content on soil dynamic properties at CAO site

2002 ◽  
Vol 22 (4) ◽  
pp. 297-308 ◽  
Author(s):  
Juan C. Carvajal ◽  
Vı́ctor M. Taboada-Urtuzuástegui ◽  
Miguel P. Romo
Keyword(s):  
Dynamic Properties ◽  
Frequency Content ◽  
Earthquake Frequency ◽  
Soil Dynamic
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