scholarly journals Study of the influence of the foundation and the reservoir on the dynamic response in a concrete gravity dam profile

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Iarly Vanderlei da Silveira ◽  
Lineu José Pedroso ◽  
Giuliano Santa Marotta
Keyword(s):  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Coupled System ◽  
Seismic Excitation ◽  
The Finite Element Method ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Ansys Apdl ◽  
Maximum Stresses

abstract: This work aims to verify the influence of the foundation and the reservoir on the dynamic behavior of concrete gravity dams in terms of the natural frequencies, vibration modes for a free vibration analysis; and in terms of maximum displacements and maximum stresses at singular points of the structure for a seismic excitation. The dam-reservoir-foundation interaction was investigated through modal and transient analysis by the finite element method via ANSYS APDL software. For this study, we used a typical Brazilian dam profile and compatible data from a Brazilian earthquake for the seismic excitation. The results showed the influence of the reservoir and the foundation on the natural frequencies in the coupled system, as well as its repercussions on the response of the dam under seismic excitation.

Application of Digital Simulation Software ANSYS in Rolling Concrete Dams Construction Technology

2011 ◽  
Vol 704-705 ◽  
pp. 352-357
Author(s):  
Gui Xiang Zeng
Keyword(s):  
Digital Simulation ◽  
Simulation Software ◽  
Construction Technology ◽  
Dynamic Features ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Dam ◽  
Concrete Gravity Dams ◽  
Xinjiang Autonomous Region ◽  
Important Significance

Taking a large hydropower station in Xinjiang Autonomous Region as an example, and based on the limited unit method, the structure and seism forces features and response rules of rolling concrete gravity dam under different construction conditions were studied. The purpose for the paper is to understand dam working status under the different design conditions, and to evaluate anti-earthquake safety capability. It is proved that the present findings should play an important significance in the development of rolling concrete dam construction technology. Key words: Rolling Concrete Gravity Dams, Limited Unit Methods, Static Force Analysis, Dynamic Features.

Uncertain Structural Free Vibration Analysis With Non-Probabilistic Spatially Varying Parameters

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Jinwen Feng ◽  
Qingya Li ◽  
Alba Sofi ◽  
Guoyin Li ◽  
Di Wu ◽  
...  
Keyword(s):  
Free Vibration ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Spatial Dependency ◽  
The Finite Element Method ◽  
Engineering Structures ◽  
Spatially Varying ◽  
Computational Strategy ◽  
Bounded System

The uncertain free vibration analysis of engineering structures with the consideration of nonstochastic spatially dependent uncertain parameters is investigated. A recently proposed concept of interval field is implemented to model the intrinsic spatial dependency of the uncertain-but-bounded system parameters. By employing the appropriate discretization scheme, evaluations of natural frequencies for engineering structures involving interval fields can be executed within the framework of the finite element method. Furthermore, a robust, yet efficient, computational strategy is proposed such that the extreme bounds of natural frequencies of the structure involving interval fields can be rigorously captured by performing two independent eigen-analyses. Within the proposed computational analysis framework, the traditional interval arithmetic is not employed so that the undesirable effect of the interval overestimation can be completely eliminated. Consequently, both sharpness and physical feasibility of the results can be guaranteed to a certain extent for any discretized interval field. The plausibility of the adopted interval field model, as well as the feasibility of the proposed computational scheme, is clearly demonstrated by investigating both academic-sized and practically motivated engineering structures.

scholarly journals Research and Application of a Seismic Damage Classification Method of Concrete Gravity Dams Using Displacement in the Crest

2020 ◽  
Vol 10 (12) ◽  
pp. 4134
Author(s):  
Xiang Lu ◽  
Liang Pei ◽  
Jiankang Chen ◽  
Zhenyu Wu ◽  
Chen Chen
Keyword(s):  
Failure Modes ◽  
Seismic Damage ◽  
Classification Method ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Damage Classification ◽  
Residual Displacement ◽  
Concrete Gravity Dams ◽  
Damage Coefficient

Concrete gravity dams are one of the most common water retention structures, some of which are located in seismically active regions. Determination of damage level after earthquakes plays an important role in assessing the safety behavior of concrete dams. Compared with the traditional performance parameters obtained from numerical simulations, such as the damage coefficient, energy dissipation, failure modes, and stress state, etc., the displacement of dams can be acquired from daily monitoring data conveniently and quickly. It is of great significance for the rapid and effective evaluation of dam properties after earthquakes. The residual displacement in the concrete gravity dam crest was adopted as the performance parameter in the paper, and the linear mapping function between the residual displacement and the damage coefficient was established based on the concrete damaged plasticity model (CDP). Based on the traditional classification method with damage coefficient, a residual displacement-based seismic damage classification method with corresponding level limits was proposed. The seismic fragility analysis of Guandi concrete gravity dam was conducted as an example to illustrate the presented methodology. The results indicate that the proposed method is reasonable, effective, and can be easily applied to different projects after slight modifications.

scholarly journals Reliability analysis of built concrete dam

2019 ◽  
Vol 12 (3) ◽  
pp. 551-579
Author(s):  
K. O. PIRES ◽  
A. T. BECK ◽  
T. N. BITTENCOURT ◽  
M. M. FUTAI
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Design Parameters ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Deterministic Method ◽  
Concrete Dam ◽  
Case Study Analysis ◽  
Concrete Gravity Dams

Abstract The conventional design of concrete gravity dams still follows the deterministic method, which does not directly quantify the effect of uncertainties on the safety of the structure. The theory of structural reliability allows the quantification of safety of these structures, from the quantification of the inherent uncertainties in resistance and loading parameters. This article illustrates application of structural reliability theory to the case study analysis of a built concrete gravity dam. Results show that reliability of the built structure is greater than that of the designed structure. The study compares reliability for design conditions, with the corresponding safety coefficients, illustrating a lack of linearity between safety coefficients and reliability. Furthermore, the study shows which are the failure modes and the design parameters with greater influence on dam safety.

scholarly journals The Failure Mechanism of Concrete Gravity Dams considering Different Nonlinear Models under Strong Earthquakes

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chunli Yan ◽  
Jin Tu ◽  
Deyu Li ◽  
Shengshan Guo ◽  
Hui Liang
Keyword(s):  
Nonlinear Models ◽  
Failure Process ◽  
Damage Model ◽  
Dynamic Contact ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Seismic Capacity ◽  
Gravity Dams ◽  
Strong Earthquakes ◽  
Concrete Gravity Dams

The paper focuses on the failure process and mechanism of the concrete gravity dam considering different nonlinear models under strong earthquakes. By taking a typical monolith of a concrete gravity dam as a case study, a comparative analysis of the failure process and mechanism of the dam considering the plastic damage model and the dynamic contact model, respectively, is performed using the seismic overload method. Moreover, the ultimate seismic capacity of the dam is evaluated for both of the nonlinear models. It is found that the ultimate seismic capacity of the dam is slightly different, but the failure process has significant distinctions in each model. And, the damage model is recommended when the conditions permit.

scholarly journals Numerical Simulation of Shock Response and Dynamic Fracture of a Concrete Dam Subjected to Impact Load

2016 ◽  
Vol 20 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lu Lu ◽  
Xin Li ◽  
Jing Zhou ◽  
Genda Chen ◽  
Dong Yun
Keyword(s):  
Dynamic Fracture ◽  
Impact Load ◽  
Failure Process ◽  
Gravity Dam ◽  
Strong Impact ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Shock Response ◽  
The Impact

<p>The shock response and dynamic fracture of concrete gravity dams under impact load are the key problems to evaluate the antiknock safety of the dam. This study aims at understanding the effects of impact shock on the elastic response and dynamic fracture of concrete gravity dams. Firstly, this paper uses acceleration records of a concrete gravity dam under impact to establish the correct way to determine the concrete gravity dam of the fundamental frequency and present cut sheets multi-degree-of-freedom dynamic modeling. Under strong impact loading, the constitutive relation of concrete gravity dam and the highest frequency of the impact are uncertain. So, the main advantage of this method is avoiding the use of elastic modulus in the calculation. The result indicates that the calculation method is a reliable computational method for concrete gravity dams subjected to impact. Subsequently, the failure process of dam models was numerically simulated based on ABAQUS commercial codes. Finally, this paper puts forward suggestions for future research based on the results of the analysis.</p>

On the Optimum Layout of a Drainage Gallery in Concrete Gravity Dams On Isotropic Foundation

2019 ◽  
Vol 25 (4) ◽  
pp. 345-358
Author(s):  
Tameem Daghestani ◽  
Melih Calamak ◽  
Ali Melih Yanmaz
Keyword(s):  
Beam Theory ◽  
Leakage Rate ◽  
Stress Distributions ◽  
Effective Solution ◽  
The Finite Element Method ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Pump Head ◽  
Post Tension ◽  
Base Width

ABSTRACT This study investigates the optimum location of drainage galleries of concrete gravity dams under usual, unusual, and extreme loading conditions. The uplift and the stress distributions were computed using the gravity method and the beam theory, whereas the leakage rate into the gallery was determined by the finite-element method. The results show that the presence of a drainage gallery can reduce the uplift by over 60 percent compared to a non-drained case. The suitable gallery location shifts toward the upstream if the drain diameter increases and the spacing decreases. This is consistent with previous research. As the gallery is moved toward the downstream, the crack length decreases; however, this increases the uplift. The most effective solution is found to be placing the gallery 10 percent of the base width away from the heel and at the downstream water level or below and adding post-tension cables on the downstream side. This option also yields lower pumping costs by reducing the pump head.

Structural Undamped Free Vibration Analysis Based on Coefficient Reduced-Basis Method

2014 ◽  
Vol 556-562 ◽  
pp. 4214-4217
Author(s):  
Yong Hong Li ◽  
Shu Zhan Li
Keyword(s):  
Vibration Analysis ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Reduced Basis Method ◽  
Mode Shapes ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Reduced Basis ◽  
Linear Elastic ◽  
Basis Method

Using reduced-basis method, design parameters are needed to be separated from the linear elastic operators, which is time-consuming. So, an improved reduced-basis method - coefficient reduced-basis method is introduced to calculate the low order natural frequencies and mode shapes of structure. In this method, the computing process of design parameters separated from the linear elastic operators is simplified. In this paper, a truck frame is taken as an example, frequencies and mode shapes from coefficient reduced-basis method are obtained. Comparing with results from the finite element method, coefficient reduced-basis method can obtain accurate results efficiently.

scholarly journals Free vibration analysis of joined composite conical-cylindrical-conical shells containing fluid

2016 ◽  
Vol 38 (4) ◽  
pp. 249-265 ◽  
Author(s):  
Vu Quoc Hien ◽  
Tran Ich Thinh ◽  
Nguyen Manh Cuong
Keyword(s):  
Vibration Analysis ◽  
Natural Frequencies ◽  
Dynamic Stiffness ◽  
Fluid Pressure ◽  
Free Vibration Analysis ◽  
The Finite Element Method ◽  
Fluid Interface ◽  
Governing Equations ◽  
Conical Shells ◽  
Bernoulli’S Equation

A new continuous element (CE) formulation has been presented in this paper for the vibration analysis of cross-ply composite joined conical-cylindrical-conical shells containing fluid. Governing equations are obtained using thick shell theory of Midlin, taking into account the shear deflection effects. The velocity potential, Bernoulli's equation and impermeability condition have been applied to the shell-fluid interface to obtain an explicit expression for fluid pressure. The dynamic stiffness matrix has been built from which natural frequencies have been calculated. The appropriate expressions among stress resultants and deformations are extracted as continuity conditions at the joining section. A matlab program is written using the CE formulation in order to validate our model. Numerical results on natural frequencies are compared to those obtained by the Finite Element Method and validated with the available results in other investigations. This paper emphasizes advantages of CE model, the effects of the fluid filling and shell geometries on the natural frequencies of joined composite conical-cylindrical-conical shells containing fluid.

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