The Experts below are selected from a list of 9648 Experts worldwide ranked by ideXlab platform
Mohammad Amin Haririardebili - One of the best experts on this subject based on the ideXlab platform.
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risk reliability resilience r3 and beyond in Dam Engineering a state of the art review
International journal of disaster risk reduction, 2018Co-Authors: Mohammad Amin HaririardebiliAbstract:Abstract Dams are critical infra-structures whose their failure could leads to high economic and social consequences. For this reason, application of quantitative risk analysis has gained extensive attention in recent years. Dam safety management has become an indispensable part of all Dam Engineering projects worldwide. The concept of risk is heavily tied to probabilistic methods. From an Engineering point of view, a clear definition of the terminologies involved in Dam safety, and a comprehensive state-of-the-art review of the current literature are the starting points towards an effective risk-based approach. The first part of this paper provides a systematic review on the funDamental elements in uncertainty quantification. Then, different terminologies in risk-based Dam safety are explored and their inter-connections are discussed. More than 350 papers are summarized, and several tables and conceptual plots are used for extra clarification. Since no such a paper is ever published, hopefully this can unify all the future activities and improves our understanding from probabilistic risk analysis.
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strain based seismic failure evaluation of coupled Dam reservoir foundation system
Coupled Systems Mechanics, 2013Co-Authors: Mohammad Amin Haririardebili, Hasan Mirzabozorg, A GhasemiAbstract:Generally, mass concrete structural behavior is governed by the strain components. However, relevant guidelines in Dam Engineering evaluate the structural behavior of concrete Dams using stress-based criteria. In the present study, strain-based criteria are proposed for the first time in a professional manner and their applicability in seismic failure evaluation of an arch Dam are investigated. Numerical model of the Dam is provided using NSAD-DRI finite element code and the foundation is modeled to be massed using infinite elements at its far-end boundaries. The coupled Dam-reservoir-foundation system is solved in Lagrangian-Eulerian domain using Newmark-β time integration method. Seismic performance of the Dam is investigated using parameters such as the demand-capacity ratio, the cumulative inelastic duration and the extension of the overstressed/overstrained areas. Real crack profile of the Dam based on the Damage mechanics approach is compared with those obtained from stress-based and strain-based approaches. It is found that using stress-based criteria leads to conservative results for arch action while seismic safety evaluation using the proposed strain-based criteria leads to conservative cantilever action.
Vahid Lotfi - One of the best experts on this subject based on the ideXlab platform.
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a symmetric implementation of pressure based fluid structure interaction for nonlinear dynamic analysis of arch Dams
Journal of Fluids and Structures, 2017Co-Authors: Omid Omidi, Vahid LotfiAbstract:Abstract Fluid–structure interaction formulated in the Lagrangian–Eulerian approach with pressure-based fluid elements, which inherently results in non-symmetric matrices, is commonly treated by either direct un-symmetric solvers or staggered solution methods. Developing an in-house finite element code called SNACS, we implement the pressure-based Eulerian formulation so that a usual symmetric solver can be employed for Dam–reservoir interaction analyses. The equilibrium equations of motion for such a coupled system are directly integrated herein by the HHT time marching algorithm in an incremental–iterative solution procedure to tackle a highly nonlinear dynamic analysis of jointed arch Dams. The HHT time integration scheme is able to Damp out high-frequency noises resulting from sudden changes in the stiffness due to opening/closing of pre-existing joints during an earthquake. First, a Pseudo-Symmetric technique is proposed to store the total matrices and solve the coupled non-symmetric equations in a symmetric manner. Then, the interface element formulation and stress update procedures of two discrete crack constitutive models suitable for contraction and peripheral joints of arch Dams are detailed. Afterwards, results of the analysis on a typical arch Dam are compared with the case in which the interaction is approximately represented by added masses as a widely-used method in Dam Engineering practice to illustrate the effects of water compressibility and reservoir bottom absorption. Besides, the straightforward implementation of pressure-based fluid–structure interaction utilizing a symmetric solution strategy is validated herein to be efficient for a 3-D large scale practical usage in other finite element codes even the commercial ones to avoid using un-symmetric solvers. Employing this symmetric implementation for the Dam–water interaction drastically reduces the computational effort, particularly when an iterative scheme is required to solve such a highly nonlinear system.
Mitsuhiro Murasaki - One of the best experts on this subject based on the ideXlab platform.
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LSPIV implementation for environmental flow in various laboratory and field cases
Journal of Hydro-environment Research, 2011Co-Authors: S.a. Kantoush, Anton Schleiss, Tesuya Sumi, Mitsuhiro MurasakiAbstract:Large-Scale Particle Image Velocimetry (LSPIV) is an extension of a quantitative imaging technique to measure water surface velocities using simple and inexpensive equipment. This paper describes the implementation of imaged-based LSPIV in eight different environmental flow and hydraulic Engineering applications for the investigation of complex configurations with and without sediment transport (bed and suspended loads). These applications include the investigation of sedimentation in shallow reservoirs, run-of-river hydropower plants, side weirs used to control bank overflow, flow fields in different spillway configurations with and without Piano Key Weir (PKW), oil spills with flexible and rigid barriers, groin fields, river confluence, and sediment flushing in reservoirs. The paper summarises some special problems encountered in such study cases. The selection and adjustments of the parameters to solve them properly were examined. The potential of LSPIV to measure surface flow velocities in the context of river and Dam Engineering projects is shown. Despite significant variations of natural and artificial illuminations and seeding tracers in the laboratory, field, wind, and water surface elevation, LSPIV was applied successfully to obtain velocity measurements. LSPIV has proven to be a reliable, flexible, and inexpensive flow diagnostic tool that can be employed successfully in many Engineering applications.
S.a. Kantoush - One of the best experts on this subject based on the ideXlab platform.
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LSPIV implementation for environmental flow in various laboratory and field cases
Journal of Hydro-environment Research, 2011Co-Authors: S.a. Kantoush, Anton Schleiss, Tesuya Sumi, Mitsuhiro MurasakiAbstract:Large-Scale Particle Image Velocimetry (LSPIV) is an extension of a quantitative imaging technique to measure water surface velocities using simple and inexpensive equipment. This paper describes the implementation of imaged-based LSPIV in eight different environmental flow and hydraulic Engineering applications for the investigation of complex configurations with and without sediment transport (bed and suspended loads). These applications include the investigation of sedimentation in shallow reservoirs, run-of-river hydropower plants, side weirs used to control bank overflow, flow fields in different spillway configurations with and without Piano Key Weir (PKW), oil spills with flexible and rigid barriers, groin fields, river confluence, and sediment flushing in reservoirs. The paper summarises some special problems encountered in such study cases. The selection and adjustments of the parameters to solve them properly were examined. The potential of LSPIV to measure surface flow velocities in the context of river and Dam Engineering projects is shown. Despite significant variations of natural and artificial illuminations and seeding tracers in the laboratory, field, wind, and water surface elevation, LSPIV was applied successfully to obtain velocity measurements. LSPIV has proven to be a reliable, flexible, and inexpensive flow diagnostic tool that can be employed successfully in many Engineering applications.
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large scale particle image velocimetry applications for complex free surface flows in river and Dam Engineering
33rd IAHR Congress "Water Engineering for a Sustainable Environment", 2009Co-Authors: M Bieri, S.a. Kantoush, Jenzer J Althaus, J L BoillatAbstract:Note: [662] Reference LCH-CONF-2009-010 URL: http://content.asce.org/conferences/iahr09/ Record created on 2009-10-08, modified on 2016-08-08
Omid Omidi - One of the best experts on this subject based on the ideXlab platform.
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a symmetric implementation of pressure based fluid structure interaction for nonlinear dynamic analysis of arch Dams
Journal of Fluids and Structures, 2017Co-Authors: Omid Omidi, Vahid LotfiAbstract:Abstract Fluid–structure interaction formulated in the Lagrangian–Eulerian approach with pressure-based fluid elements, which inherently results in non-symmetric matrices, is commonly treated by either direct un-symmetric solvers or staggered solution methods. Developing an in-house finite element code called SNACS, we implement the pressure-based Eulerian formulation so that a usual symmetric solver can be employed for Dam–reservoir interaction analyses. The equilibrium equations of motion for such a coupled system are directly integrated herein by the HHT time marching algorithm in an incremental–iterative solution procedure to tackle a highly nonlinear dynamic analysis of jointed arch Dams. The HHT time integration scheme is able to Damp out high-frequency noises resulting from sudden changes in the stiffness due to opening/closing of pre-existing joints during an earthquake. First, a Pseudo-Symmetric technique is proposed to store the total matrices and solve the coupled non-symmetric equations in a symmetric manner. Then, the interface element formulation and stress update procedures of two discrete crack constitutive models suitable for contraction and peripheral joints of arch Dams are detailed. Afterwards, results of the analysis on a typical arch Dam are compared with the case in which the interaction is approximately represented by added masses as a widely-used method in Dam Engineering practice to illustrate the effects of water compressibility and reservoir bottom absorption. Besides, the straightforward implementation of pressure-based fluid–structure interaction utilizing a symmetric solution strategy is validated herein to be efficient for a 3-D large scale practical usage in other finite element codes even the commercial ones to avoid using un-symmetric solvers. Employing this symmetric implementation for the Dam–water interaction drastically reduces the computational effort, particularly when an iterative scheme is required to solve such a highly nonlinear system.
