Parallel computation of seismic analysis of high arch dam (original) (raw)
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Numerical effect of seismic force on a medium arch dam
Water Practice & Technology, 2022
The dam is considered a huge structure that has multiple purposes in the life of a human. The most important role of a dam is the production of electricity, and the storage of a huge quantity of water. Therefore, it is very important to be vigilant in the studies made for it. Lebanon has indeed been designated as a seismicity country. However, the number of dams is increasing due to several natural consideration. Mseilha dam is an executed medium arch dam, which faced several problems during and after construction. The initial problem that faced a dam is the seismic force. This natural force is very dangerous for any structure, especially for a dam. It could increase the existing concrete stresses. These stresses will cause the development of cracks all along the dam. Once the concrete shows cracks, its resistance will decrease, and it will become more vulnerable to external effects. Several studies were made to fortify it and make it resistant to seismic force. To show the major effect of this force, two methods 'pseudo-static' and 'response spectrum' were applied to a medium arch dam. Therefore, to evaluate the performance of these two methods, the dam is modeled using finite element software. The obtained results show the importance of using the appropriate model in the design of such dams without taking the appropriate model.
Seismic Analyis of Concrete Arch Dams - Two Case Studies
Proceedings of 10th World Congress on Computational Mechanics, 2014
In the framework of the Portuguese National Programme for Dams with High Hydroelectric Potential (PNBEPH), a set of large concrete dams is currently under design or construction, including several 100 m high arch dams. Earthquake loading is one of the important aspects to be considered in the design of these structures. A variety of numerical methods have been developed over the years by various researchers and are presently available for seismic analysis of concrete dams. The methods in use by the dam engineering community have different approaches, for example, in the representation of the seismic action, the dam-water interaction or the structural nonlinear behavior. In the paper, the models applied in the study of new Portuguese dams are presented, and their fundamental assumptions discussed. In particular, the analysis of the response of arch dams to the Maximum Design Earthquake is examined, considering the non-elastic behavior of the contraction joints and the dam foundation. An explicit time integration algorithm was used in these simulations, allowing a detailed representation of the slip and separation events along the discontinuities. The boundary conditions appropriate for seismic analysis are discussed, namely the type of free-field boundaries employed. In the paper, the application of this modeling methodology to two new dams is presented and discussed. Foz Tua dam, that is already under construction, is a concrete arch dam, 108 m high and 275 m long at the crest. Fridão dam is also a concrete arch dam, 98 m high and with a crest length of 300 m. Design criteria and the results of the numerical analyses are discussed.
Earthquake risk reduction and seismic safety evaluation of arch dams using finite elements
14th World Conference on Earthquake Engineering, 2008
Uncertainty in seismic behavior of arch dams due to the effect of foundation and reservoir interaction is an important issue in the seismic safety evaluation of existing dams. In the present paper, a direct time domain procedure is used for dynamic analysis of the coupled system of reservoir-dam-foundation in 3D space. In the present paper, it is attempted to simulate the foundation radiation effect on the system by infinite elements and the reservoir water is assumed to be compressible. Material nonlinearity of the mass concrete is modeled by smeared crack approach which is able to simulate the non-uniform cracking within the finite elements of the dam body. Amir-kabir arch dam in Iran is chosen as a case study to investigate the nonlinear seismic behavior of the coupled system. It is realized that the crack profiles within the dam body are less when the foundation is assumed massed. It is found that the proposed numerical algorithm is useful in seismic safety evaluation of arch dams in 3D space and the assumptions in the pertinent environments within the coupled problem are more realistic. Due to the reduction of the seismic response of the coupled system, it is expected to reduce the seismic risk of dams using more real assumptions in the numerical models.
A Concrete Arch Dam under Seismic Loading Conditions
A new regulation for the safety assessment of dams has just been developed in Italy and its approval process is still in progress. As a matter of fact the behaviour of dams under seismic loading conditions is deemed of actual interest due to the recent seismic events occurred. In earthquake analysis, some of the most challenging aspects dam engineers have to deal with are: the capability to take duly into account the dam-reservoir and foundation rock-reservoir interactions; a careful evaluation of the maximum displacements/stresses of the concrete structures; a proper choice of constitutive models. This paper shows how COMSOL Multiphysics can afford the safety assessment of a large concrete arch dam under dynamic excitation, taking into account the dam-reservoir and foundation rock-reservoir interactions as well.
Seismic analysis of concrete arch dams considering different foundation conditions
Sakarya University Journal of Science, 2019
Earthquake response of arch dams should be calculated under strong ground motion effects. In this study, threedimensional linear response of an arch dam is investigated. The hydrodynamic effect of water is taken into account with Westergaard approach. Different ground motion effects and also foundation conditions are considered in the finite element analyses. For this purpose, the Type 3 double curvature arch dam was selected for numerical examples. All numerical analyses are carried out by SAP2000 program for full reservoir cases. According to numerical analyses, maximum horizontal displacements and maximum normal stresses are presented by dam height in the largest section. These results are evaluated for five different elastic foundation conditions. The selected foundation conditions of the all models have different sandstone material parameters. Furthermore, near-fault and far-field ground motion effects on the selected arch dam are taken into account by different accelerograms obtained from the Loma Prieta earthquake at various distances.
Seismic analysis of concrete arch dams considering hydrodynamic effect using Westergaard approach
Sakarya Üniversitesi Fen Bilimleri Enstitüsü Dergisi, 2019
Earthquake response of arch dams should be calculated under strong ground motion effects. In this study, three-dimensional linear response of an arch dam is investigated. Different ground motion effects and also foundation conditions are considered in the finite element analyses. For this purpose, the Type 3 double curvature arch dam was selected for numerical examples. All numerical analyses are carried out by SAP2000 program for empty reservoir cases. According to numerical analyses, maximum horizontal displacements and maximum normal stresses are presented by dam height in the largest section. These results are evaluated for five different elastic foundation conditions. The selected foundation conditions of the all models have different sandstone material parameters. Furthermore, near-fault and far-field ground motion effects on the selected arch dam are taken into account by different accelerograms obtained from the Loma Prieta earthquake at various distances.
The interaction between dam foundation and rocks plays a significant role in the design and analysis of concrete arch dams. In the current study, comprehensive dynamic analysis of the dam-reservoir-foundation system is performed by developing a non-linear finite element program. The objective of this paper is to study the seismic behavior of a concrete arch dam taking into account the effects of foundation discontinuities and foundation inhomogeneity on the stability. Proper modeling truncated boundary conditions at the far-end of the foundation and reservoir fluid domain as well as to correctly apply the in-situ stresses for the foundation rock represents field conditions in the model more realistically. In this paper, the nonlinear seismic response of the dam-reservoir-foundation system includes dam-canyon interaction, dam body contraction joint opening, discontinuities (possible sliding planes) of the foundation rock and the failure of the joined rock and concrete materials. The results for the Karun 4 dam as a case study revealed the substantial effect of modeling discontinuities and boundary conditions of the rock foundation under seismic excitation that needs to be considered in the design of new dams and can be applied to seismic safety evaluation of the existing dams.
Earthquake Analysis of Concrete Arch Dams Considering Elastic Foundation Effects
2016
Dynamic effects on an arch dam should be taken into account for the ground motions. This study presents threedimensional linear earthquake response of an arch dam. Different ground motion effects and besides rigid and elastic foundation conditions are considered in the finite element analyses. For this purpose, the Type 3 double curvature arch dam was selected due to numerical solutions. All numerical analyses are carried out by SAP2000 V.17 program for empty reservoir case. In the scope of this study, linear modal time-history analyses are performed using three dimensional finite element model of the arch dam and arch dam-foundation interaction systems. Furthermore, near-fault and far field ground motion effects on the selected arch dam were taken into account by different accelerograms obtained from the Loma Prieta earthquake at various distances. According to numerical analyses, maximum horizontal displacements and maximum normal stresses are presented by height and these are eva...
ISRN Civil Engineering, 2012
Seismic failure of major concrete dams can be disastrous due to sudden release of reservoir water. At the present study, 203 m DEZ arch dam was selected as case study, and two types of nonlinearity were incorporated in seismic analysis of dam, joint nonlinearity and material nonlinearity. The finite element model of the dam, soil, and water was excited using multicomponent maximum design earthquake record which was extracted from seismic hazard analysis of the dam site. Also seismic performance of the dam was evaluated based on linear analysis. The extension of overstressed areas, demand-capacity ratio, and cumulative inelastic duration were used to identify the necessity of nonlinear analysis. It was found that when contraction joints between dam blocks are modeled, the direction of the principal stresses and their distribution patterns are changed meaningfully. In addition, overstress surfaces on the dam body change in comparison with the model without contraction joints.
Seismic Response Predication of Concrete Arch Dam
Department of Civil Engineering, Jamia Millia Islamia New Delhi, 2017
The performance evaluation of concrete arch dam under dynamic excitation is a challenging task which requires the comprehensive knowledge of modeling aspects. This paper summarizes important and critical parameters to be considered during dynamic analysis of concrete arch dams. A comprehensive review work is carried out in order to identify the factors which influence significantly the three-dimensional analysis of arch dams.