Rational Transmitting Boundaries for Time-Domain Analysis of Dam-Reservoir Interaction

Rational Transmitting Boundaries for Time-Domain Analysis of Dam-Reservoir Interaction PDF

Author: Benedikt Weber

Publisher: Birkhäuser

Published: 2013-06-29

Total Pages: 273

ISBN-13: 303487751X

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Most existing arch dams have been designed for seismic loading by static methods involving the use of seismic coefficients. Although there are no known examples of arch dams which have been seriously damaged by earthquakes, the need for more realistic seismic analyses is now well recognized, not only for new dams but especially in the context of the safety evaluation of existing dams. Fortunately, with the finite element method, engineers have a powerful tool for modeling the complex geometry and the nonlinear material behavior of a dam. However, there is still a major complication in the analysis procedure, namely the interaction of the dam with the reservoir and with the foundation during an earthquake. Interaction is a wave propagation problem involving transmitting boundaries. The State of the Art in engineering practice is to neglect wave propagation by modeling the water as incompressible and the foundation as massless. More advanced analysis methods using compressible water and foundation with mass have been available for some time. However, these methods are restricted to linear models, because they work in the frequency domain. On the other hand, there are also advanced nonlinear models for dams, but they can only be used in the time domain, usually with simple transmitting boundaries. In this report, which is based on an a doctoral thesis, rigorous transmitting boundaries in the time domain are developed which permit combining compressible water with n- linear dam behavior. The new numerical model is based on a systems-theory approach.

Hydrodynamics

Hydrodynamics PDF

Author: Harry Schulz

Publisher: BoD – Books on Demand

Published: 2012-01-05

Total Pages: 304

ISBN-13: 9533078936

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The knowledge of the characteristics of the fluids and their ability to transport substances and physical properties is relevant for us. However, the quantification of the movements of fluids is a complex task, and when considering natural flows, occurring in large scales (rivers, lakes, oceans), this complexity is evidenced. This book presents conclusions about different aspects of flows in natural water bodies, such as the evolution of plumes, the transport of sediments, air-water mixtures, among others. It contains thirteen chapters, organized in four sections: Tidal and Wave Dynamics: Rivers, Lakes and Reservoirs, Tidal and Wave Dynamics: Seas and Oceans, Tidal and Wave Dynamics: Estuaries and Bays, and Multiphase Phenomena: Air-Water Flows and Sediments. The chapters present conceptual arguments, experimental and numerical results, showing practical applications of the methods and tools of Hydrodynamics.

Absorbing Boundaries for the Time-Domain Analysis of Dam-Reservoir-Foundation Systems

Absorbing Boundaries for the Time-Domain Analysis of Dam-Reservoir-Foundation Systems PDF

Author: Glauco Feltrin

Publisher: Birkhäuser

Published: 2014-09-12

Total Pages: 0

ISBN-13: 9783034876100

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This report deals with the modeling and analysis of the earthquake behavior of concrete gravity dams. This task becomes very challenging when the interaction with the reservoir and foundation has to be considered. In addition, a concrete gravity dam may get severely damaged by dynami cally propagating cracks when subjected to a severe earthquake ground motion. This strongly nonlinear behavior of dams impedes the application of state-of-the-art frequency-domain meth ods for the analysis because the Superposition principle is no longer valid. As a consequence, the model has to be formulated in the time domain complicating the analysis even more. In this report, which is based on a doctoral thesis, a new method is presented that permits to develop absorbing boundary conditions for the nonlinear time-domain analysis of concrete grav ity dams. These conditions are based on a approximation of dynamic stiffness matrices using series of orthogonal functions and advanced model reduction techniques of linear systems theory. The new absorbing boundary conditions are very accurate so that they are virtually equivalent to dynarnic stiffness matrices obtained by a rigorous solution of a far field. This allows to reduce the size of near fields dramatically and permits an accurate and numerically efficient nonlinear time domain analysis.

Validation of Dynamic Analyses of Dams and Their Equipment

Validation of Dynamic Analyses of Dams and Their Equipment PDF

Author: Jean-Jacques Fry

Publisher: CRC Press

Published: 2018-06-27

Total Pages: 802

ISBN-13: 0429957076

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Validation of Dynamic Analyses of Dams and Their Equipment is the outcome of a three year cooperation program between CFBR (Comite Francais des Barrages et Reservoirs or French Committee on Large dams) and JCOLD (Japan Commission on Large Dams), and focusses on the dynamic behavior of concrete and embankment dams analyzed based on acceleration records of the JCOLD data base. The book covers a broad range of topics, including simplified and detailed methods of dynamic analysis for the seismic response of concrete and embankment dams compared with measured behavior. The response of embankment dams subjected to a 1.0 g foundation acceleration time history is computed by several analytical methods and compared. The modelling of stress-strain behavior of compacted soils for seismic stability analysis of earth-fill dams and its application for a failed earthfill dam is described. The cracking of the face slab of four faced rockfill dams during earthquakes is analyzed. The seismic behavior of concrete arch dams is discussed by the comparison of numerical and experimental results. Displacement-based seismic assessment of concrete dams is presented. Finally the book contains a comparison between the Japanese and French design criteria of gates and a comparison of the analysis of gates and field measurements. Validation of Dynamic Analyses of Dams and Their Equipment will be useful to professional and academics involved or interested in dam engineering.

Absorbing Boundaries for the Time-Domain Analysis of Dam-Reservoir-Foundation Systems

Absorbing Boundaries for the Time-Domain Analysis of Dam-Reservoir-Foundation Systems PDF

Author: Glauco Feltrin

Publisher: Birkhäuser

Published: 2000-10-11

Total Pages: 263

ISBN-13: 9783764358693

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This report deals with the modeling and analysis of the earthquake behavior of concrete gravity dams. This task becomes very challenging when the interaction with the reservoir and foundation has to be considered. In addition, a concrete gravity dam may get severely damaged by dynami cally propagating cracks when subjected to a severe earthquake ground motion. This strongly nonlinear behavior of dams impedes the application of state-of-the-art frequency-domain meth ods for the analysis because the Superposition principle is no longer valid. As a consequence, the model has to be formulated in the time domain complicating the analysis even more. In this report, which is based on a doctoral thesis, a new method is presented that permits to develop absorbing boundary conditions for the nonlinear time-domain analysis of concrete grav ity dams. These conditions are based on a approximation of dynamic stiffness matrices using series of orthogonal functions and advanced model reduction techniques of linear systems theory. The new absorbing boundary conditions are very accurate so that they are virtually equivalent to dynarnic stiffness matrices obtained by a rigorous solution of a far field. This allows to reduce the size of near fields dramatically and permits an accurate and numerically efficient nonlinear time domain analysis.

Seismic Safety Evaluation of Concrete Dams

Seismic Safety Evaluation of Concrete Dams PDF

Author: Chong Zhang

Publisher: Elsevier

Published: 2014-10-23

Total Pages: 671

ISBN-13: 0124079199

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The consequences of a large dam failing can be disastrous. However, predicting the performance of concrete dams during earthquakes is one of the most complex and challenging problems in structural dynamics. Based on a nonlinear approach, Seismic Safety Evaluation of Concrete Dams allows engineers to build models that account for nonlinear phenomena such as vertical joint slippage, cracks, and cavitation. This yields more accurate estimates. Advanced but readable, this book is the culmination of the work carried out by Tsinghua University Research Group on Earthquake Resistance on Dams over the last two decades. Nonlinearity characteristics of high concrete dams, seismic analysis methods, evaluation models A systematic approach to nonlinear analysis and seismic safety evaluation of concrete dams Includes nonlinear fracture of dam-water-foundation interaction system, dynamic fluid-structure Covers soil-structure interactions, and meso-scale mechanical behavior of concrete are all international front issues of the field

Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems

Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems PDF

Author: Alphose Zingoni

Publisher: CRC Press

Published: 2022-09-02

Total Pages: 4438

ISBN-13: 1000824365

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Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems comprises 330 papers that were presented at the Eighth International Conference on Structural Engineering, Mechanics and Computation (SEMC 2022, Cape Town, South Africa, 5-7 September 2022). The topics featured may be clustered into six broad categories that span the themes of mechanics, modelling and engineering design: (i) mechanics of materials (elasticity, plasticity, porous media, fracture, fatigue, damage, delamination, viscosity, creep, shrinkage, etc); (ii) mechanics of structures (dynamics, vibration, seismic response, soil-structure interaction, fluid-structure interaction, response to blast and impact, response to fire, structural stability, buckling, collapse behaviour); (iii) numerical modelling and experimental testing (numerical methods, simulation techniques, multi-scale modelling, computational modelling, laboratory testing, field testing, experimental measurements); (iv) design in traditional engineering materials (steel, concrete, steel-concrete composite, aluminium, masonry, timber); (v) innovative concepts, sustainable engineering and special structures (nanostructures, adaptive structures, smart structures, composite structures, glass structures, bio-inspired structures, shells, membranes, space structures, lightweight structures, etc); (vi) the engineering process and life-cycle considerations (conceptualisation, planning, analysis, design, optimization, construction, assembly, manufacture, maintenance, monitoring, assessment, repair, strengthening, retrofitting, decommissioning). Two versions of the papers are available: full papers of length 6 pages are included in the e-book, while short papers of length 2 pages, intended to be concise but self-contained summaries of the full papers, are in the printed book. This work will be of interest to civil, structural, mechanical, marine and aerospace engineers, as well as planners and architects.

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