Seismic Design of a Double Deck Floating Roof Type Used for Liquid Storage Tanks

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Mohammad Ali Goudarzi
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Hydrodynamic Pressure ◽  
Nonlinear Effects ◽  
Vertical Displacement ◽  
Bottom Plate ◽  
Liquid Storage ◽  
Geometric Nonlinear ◽  
General Displacement ◽  
Seismic Stress

Sloshing response of a cylindrical liquid storage tank with the double deck type floating roof (DDFR) subjected to seismic excitation is considered in this paper. The aim of the paper is to clarify the significant parameters that should be considered in the seismic design of a DDFR and proposing a practical seismic design procedure for evaluating the dynamic stresses inside a DDFR. A numerical method including fluid–structure interaction and the geometry details of a DDFR tank are established. The geometric nonlinear effects on the seismic behavior of the DDFR as well as the accuracy of common analytical solution suggested in the literature are examined by the numerical model. The numerical results show that the geometric nonlinear effects can considerably reduce the seismic stress in DDFR, but have no significant effect on the liquid hydrodynamic pressure exerted on the DDFR and the roof's vertical displacement. It is also revealed that not only the general displacement of DDFR but also the local effects of liquid hydrodynamic pressure on the bottom plate should be considered for seismic design of a DDFR. Finally, a design procedure for the evaluation of dynamic stress in the DDFR due to the seismic loads is proposed and discussed.

scholarly journals Generalized SDOF system for dynamic analysis of concrete rectangular liquid storage tanks

2021 ◽  
Author(s):  
Jun Zheng Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Seismic Analysis ◽  
Design Procedure ◽  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Tank Wall ◽  
Storage Tanks ◽  
Sdof System ◽  
Liquid Storage

Liquid storage tanks are essential facilities in lifeline and industrial systems. To ensure liquid tightness, serviceability is the prime design concern for these structures. While there have been major studies on the behavior of steel tanks, little attention has been paid to the behavior of rectangular concrete tanks. In this study, the dynamic response of concrete rectangular liquid storage tanks is investigated. In the current design practice, the response of liquid and tank structure is determined based on rigid tank wall and the lumped mass approach. However, the results of analysis show that the flexibility of tank wall increases the hydrodynamic pressures as compared to the rigid wall assumption. Also, recent studies show that the lumped added mass method leads to overly conservative results in terms of base shear and base moment. In addition, in spite of advanced analysis techniques available for dynamic analysis of liquid storage tanks such as finite element method and sequential coupling analysis procedure, there is a need to develop a simplified analysis method for practical applications. In this thesis, a simplified method using the generalized single degree of freedom (SDOF) system is proposed for seismic analysis of concrete rectangular liquid containing structures (LCS). Only the impulsive hydrodynamic pressure is considered. In the proposed method, the consistent mass approach and the effect of flexibility of tank wall on hydrodynamic pressures are considered. Different analytical methods are used to verify the proposed model in this study. The comparison of results based on the current design practice, the analytical-finite element models and full finite element model using ANSYS® shows that the proposed method is fairly accurate which can be used in the structural design of liquid containing structures. Parametric studies on seismic analysis of concrete rectangular LCS using the generalized SDOF system are carried out. Five prescribed vibration shape functions representing the first mode shape of fluid structure interaction system are used to study the effect of flexibility of tank wall and boundary conditions. The effect of flexibility of tank wall, the amplitude of hydrodynamic pressure, the added mass of liquid due to hydrodynamic pressure, the effective heights for liquid containing system and the effect of higher modes on dynamic response of LCS are investigated. In addition, the effect of variable size of tanks and liquid depth are studied. The contribution of higher modes to the dynamic response of LCS is included in the proposed model. A design procedure based on the structural model using the generalized SDOF system is proposed in this study. Design charts and tables for the added mass of liquid due to impulsive hydrodynamic pressure and the corresponding effective heights are presented. The proposed design procedure can be used for engineering design applications.

scholarly journals Generalized SDOF system for dynamic analysis of concrete rectangular liquid storage tanks

2021 ◽  
Author(s):  
Jun Zheng Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Seismic Analysis ◽  
Design Procedure ◽  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Tank Wall ◽  
Storage Tanks ◽  
Sdof System ◽  
Liquid Storage

Liquid storage tanks are essential facilities in lifeline and industrial systems. To ensure liquid tightness, serviceability is the prime design concern for these structures. While there have been major studies on the behavior of steel tanks, little attention has been paid to the behavior of rectangular concrete tanks. In this study, the dynamic response of concrete rectangular liquid storage tanks is investigated. In the current design practice, the response of liquid and tank structure is determined based on rigid tank wall and the lumped mass approach. However, the results of analysis show that the flexibility of tank wall increases the hydrodynamic pressures as compared to the rigid wall assumption. Also, recent studies show that the lumped added mass method leads to overly conservative results in terms of base shear and base moment. In addition, in spite of advanced analysis techniques available for dynamic analysis of liquid storage tanks such as finite element method and sequential coupling analysis procedure, there is a need to develop a simplified analysis method for practical applications. In this thesis, a simplified method using the generalized single degree of freedom (SDOF) system is proposed for seismic analysis of concrete rectangular liquid containing structures (LCS). Only the impulsive hydrodynamic pressure is considered. In the proposed method, the consistent mass approach and the effect of flexibility of tank wall on hydrodynamic pressures are considered. Different analytical methods are used to verify the proposed model in this study. The comparison of results based on the current design practice, the analytical-finite element models and full finite element model using ANSYS® shows that the proposed method is fairly accurate which can be used in the structural design of liquid containing structures. Parametric studies on seismic analysis of concrete rectangular LCS using the generalized SDOF system are carried out. Five prescribed vibration shape functions representing the first mode shape of fluid structure interaction system are used to study the effect of flexibility of tank wall and boundary conditions. The effect of flexibility of tank wall, the amplitude of hydrodynamic pressure, the added mass of liquid due to hydrodynamic pressure, the effective heights for liquid containing system and the effect of higher modes on dynamic response of LCS are investigated. In addition, the effect of variable size of tanks and liquid depth are studied. The contribution of higher modes to the dynamic response of LCS is included in the proposed model. A design procedure based on the structural model using the generalized SDOF system is proposed in this study. Design charts and tables for the added mass of liquid due to impulsive hydrodynamic pressure and the corresponding effective heights are presented. The proposed design procedure can be used for engineering design applications.

Design procedure for dynamic response of concrete rectangular liquid storage tanks using generalized SDOF system

2015 ◽  
Vol 42 (11) ◽  
pp. 960-965
Author(s):  
J.Z. Chen ◽  
M.R. Kianoush
Keyword(s):  
Dynamic Response ◽  
Seismic Design ◽  
Current Practice ◽  
Design Procedure ◽  
Storage Tanks ◽  
The Finite Element Method ◽  
Single Degree Of Freedom ◽  
Sdof System ◽  
Liquid Storage ◽  
Proposed Model

In this paper, a design procedure using the generalized single degree of freedom (SDOF) system is proposed for two-dimensional dynamic response of rectangular liquid containing structures (LCS). The proposed model considers the effect of flexibility of tank wall on hydrodynamic pressures and uses the consistent mass approach in dynamic analysis. The contribution of higher modes to the dynamic response of LCS is included in the proposed model. The square root of sum of squares method is proposed for the combination of the first two modes. One set of calculations for a tall tank is presented and compared with the results obtained using the current practice as well as the finite element method reported by the authors in previous investigations. The proposed method using the generalized SDOF system can be simply used in seismic design of LCS.

New Design Method to Evaluate the Seismic Stress of Single Deck Floating Roof for Storage Tanks

2015 ◽  
Vol 31 (1) ◽  
pp. 421-439 ◽  
Author(s):  
Mohammad Ali Goudarzi
Keyword(s):  
Design Method ◽  
Plane Deformation ◽  
Design Procedure ◽  
Nonlinear Behavior ◽  
Primary Source ◽  
Nonlinear Effects ◽  
Storage Tanks ◽  
Deck Plate ◽  
Out Of Plane ◽  
Seismic Stress

Liquid sloshing causes severe damage to the floating roofs of storage tanks. Liquid–roof interaction imposes a complicated distribution of out-of-plane deformation in a single deck floating roof (SDFR), which is the primary source of high seismic stress. This paper proposes a new seismic design procedure for evaluating the seismic stress of an SDFR. This method revises the relationship between vertical deformation of the deck plate and the radial shrinkage of the pontoon, and estimates the nonlinear behavior of the free surface. Moreover, the attenuation of the sloshing wave height attributable to the presence of an SDFR is analytically evaluated. A design flowchart according to the new method is suggested. This method emphasizes the nonlinear effects of large amplitude wave for smaller capacity tanks, and the seismic stress caused by the second sloshing mode for broad tanks.

Geometric Nonlinear Effect on Large Span Cable-Stayed Bridge

2014 ◽  
Vol 638-640 ◽  
pp. 942-946
Author(s):  
Shuang Rui Chen ◽  
Quan Sheng Yan
Keyword(s):  
Linear Method ◽  
Bending Moment ◽  
Nonlinear Effects ◽  
Element Model ◽  
Vertical Displacement ◽  
Displacement Effect ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Geometric Nonlinear ◽  
Main Girder

It is introduced that three main factors cause geometric nonlinear effects of long span cable-stayed bridge: large displacement effect, cable sag effect, and the combination of bending moment and axial force effect. The iteration method of geometrical nonlinear problem is also introduced. The bridge deformation was calculated by establishing a plane truss finite element model of a long-span single tower cable-stayed bridge under consideration of nonlinearity and compared with that done with linear method. It is concluded that nonlinearity influenced differently to the bending moment of main girder, the displacement of tower root and the vertical displacement of girder.

Drift-based seismic design procedure for Buckling Restrained Braced Frames

Structures ◽  
2021 ◽  
Vol 30 ◽  
pp. 62-74
Author(s):  
Seyed Amin Mousavi ◽  
Seyed Mehdi Zahrai ◽  
Ali Akhlagh Pasand
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Braced Frames ◽  
Buckling Restrained Braced Frames

Seismic Design of Liquid Storage Tanks

1981 ◽  
Vol 107 (1) ◽  
pp. 191-207
Author(s):  
Medhat A. Haroun ◽  
George W. Housner
Keyword(s):  
Seismic Design ◽  
Storage Tanks ◽  
Liquid Storage
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