Dépouillements

Three-dimensional behavior of a spherical self-centering precast prestressed pile isolator / Rosita Jünemann in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 541-564 Titre : Three-dimensional behavior of a spherical self-centering precast prestressed pile isolator Type de document : texte imprimé Auteurs : Rosita Jünemann, Auteur ; Llera (de la), Juan C., Auteur ; Jaime Besa, Auteur ; José L. Almazán Article en page(s) : pp. 541-564 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Kinematic  isolators;  Prestressed  rod;  Seismic  isolation  ;  Structural  element;  Self-centering;  Rolling  constraints Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A 3D analytical formulation of a precast prestressed pile (PPP) seismic isolator with top and bottom spherical rolling kinematic constraints is proposed. The PPP isolator was initially conceived as a low-cost seismic isolation (and foundation) system for housing units of low-income people. Since these structures are usually located at sites with poor soil conditions, the PPP isolator also works as a foundation pile by connecting the superstructure with more competent soil layers. The non-holonomic nature of the rolling constraint is dealt with by a structural formulation. The proposed 3D formulation is validated by numerical results obtained from a previously proposed formulation for the 2D problem, and a contact finite element model in ANSYS (www.ansys.com). Other issues associated with the dynamic response of isolated structures with the PPP are also examined, such as expected response reductions, variation in the axial force of the central prestressed cable, and torsional response amplifications. Finally, guidelines to estimate the actual 3D response using 2D analysis results are investigated. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122210039/abstract [article] Three-dimensional behavior of a spherical self-centering precast prestressed pile isolator [texte imprimé] / Rosita Jünemann, Auteur ; Llera (de la), Juan C., Auteur ; Jaime Besa, Auteur ; José L. Almazán . - pp. 541-564. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 541-564 Mots-clés : Kinematic  isolators;  Prestressed  rod;  Seismic  isolation  ;  Structural  element;  Self-centering;  Rolling  constraints Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A 3D analytical formulation of a precast prestressed pile (PPP) seismic isolator with top and bottom spherical rolling kinematic constraints is proposed. The PPP isolator was initially conceived as a low-cost seismic isolation (and foundation) system for housing units of low-income people. Since these structures are usually located at sites with poor soil conditions, the PPP isolator also works as a foundation pile by connecting the superstructure with more competent soil layers. The non-holonomic nature of the rolling constraint is dealt with by a structural formulation. The proposed 3D formulation is validated by numerical results obtained from a previously proposed formulation for the 2D problem, and a contact finite element model in ANSYS (www.ansys.com). Other issues associated with the dynamic response of isolated structures with the PPP are also examined, such as expected response reductions, variation in the axial force of the central prestressed cable, and torsional response amplifications. Finally, guidelines to estimate the actual 3D response using 2D analysis results are investigated. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122210039/abstract

A fibre flexure-shear model for seismic analysis of RC-framed structures / P. Ceresa in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 565-586 Titre : A fibre flexure-shear model for seismic analysis of RC-framed structures Type de document : texte imprimé Auteurs : P. Ceresa, Auteur ; L. Petrini, Auteur ; R. Pinho, Auteur ; R. Sousa Article en page(s) : pp. 565-586 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Fibre  element;  Shear  deformations;  Seismic  analysis;  Reinforced  concrete  frames Résumé : While currently existing modelling approaches of reinforced concrete (RC) behaviour allow a reasonably accurate prediction of flexural response, the determination of its shear counterpart needs further developments. There are various modelling strategies in the literature able to predict the shear response and the shear-flexure coupling under monotonic loading conditions. However, very few are the reported models that have demonstrated successful results under cyclic loading, as in the seismic load case. These considerations lead to this research work focused on the development of a flexure-shear model for RC beam-column elements. A reliable constitutive model for cracked RC subjected to cyclic loading was implemented as bi-axial fibre constitutive model into a two-dimensional Timoshenko beam-column element. Aim of this research work is to arrive at the definition of a numerical model sufficiently accurate and, at the same time, computationally efficient, which will enable implementation within a finite element package for nonlinear dynamic analysis of existing non-seismically designed RC structures that are prone to shear-induced damage and collapse. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122201890/abstract [article] A fibre flexure-shear model for seismic analysis of RC-framed structures [texte imprimé] / P. Ceresa, Auteur ; L. Petrini, Auteur ; R. Pinho, Auteur ; R. Sousa . - pp. 565-586. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 565-586 Mots-clés : Fibre  element;  Shear  deformations;  Seismic  analysis;  Reinforced  concrete  frames Résumé : While currently existing modelling approaches of reinforced concrete (RC) behaviour allow a reasonably accurate prediction of flexural response, the determination of its shear counterpart needs further developments. There are various modelling strategies in the literature able to predict the shear response and the shear-flexure coupling under monotonic loading conditions. However, very few are the reported models that have demonstrated successful results under cyclic loading, as in the seismic load case. These considerations lead to this research work focused on the development of a flexure-shear model for RC beam-column elements. A reliable constitutive model for cracked RC subjected to cyclic loading was implemented as bi-axial fibre constitutive model into a two-dimensional Timoshenko beam-column element. Aim of this research work is to arrive at the definition of a numerical model sufficiently accurate and, at the same time, computationally efficient, which will enable implementation within a finite element package for nonlinear dynamic analysis of existing non-seismically designed RC structures that are prone to shear-induced damage and collapse. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122201890/abstract

Simulation of the shaking table test of a seven-story shear wall building / Mohamed Talaat in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 609-634 Titre : Simulation of the shaking table test of a seven-story shear wall building Type de document : texte imprimé Auteurs : Mohamed Talaat, Auteur ; Khalid M. Mosalam, Auteur Article en page(s) : pp. 609-634 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Dynamic  analysis;  Element  removal;  Finite  element;  Progressive  collapse;  Reinforced  concrete  frame;  Unreinforced  masonry  infill Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a novel analytical formulation of an element removal algorithm based on dynamic equilibrium and the resulting transient change in system kinematics, by applying imposed accelerations instead of external forces at a node where an element was once connected. The algorithm is implemented into an open-source finite element code, numerically tested using a benchmark structural system with simplified element removal criteria, and able to capture the effect of uncertainty in member capacity. Realistic element removal criteria are introduced for mode-dependent gravity load collapse of seismically deficient and retrofitted reinforced concrete (RC) columns and unreinforced masonry (URM) infill walls. Two applications are conducted using structural systems of RC frames with URM infill walls. The first is a probabilistic study of a one-story model subjected to an ensemble of 14 ground motion recordings from similar neighboring sites during an earthquake event. The study produces empirical probability curves for partial and complete collapse conditioned on different hazard levels, and concludes that the intra-event variability is a major source of uncertainty affecting the outcome of progressive collapse simulations. The second application is a deterministic sensitivity study of progressive collapse response in a five-story structural model to uncertainty in live load, stiffness, damping, and seismic hazard level, subjected to one ground motion record. The analysis identifies the time at incipient collapse as an adequate sensitivity measure, and the uncertainty in ground motion intensity as the most important, followed by the stiffness of the URM infill wall. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198914/abstract [article] Simulation of the shaking table test of a seven-story shear wall building [texte imprimé] / Mohamed Talaat, Auteur ; Khalid M. Mosalam, Auteur . - pp. 609-634. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 609-634 Mots-clés : Dynamic  analysis;  Element  removal;  Finite  element;  Progressive  collapse;  Reinforced  concrete  frame;  Unreinforced  masonry  infill Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a novel analytical formulation of an element removal algorithm based on dynamic equilibrium and the resulting transient change in system kinematics, by applying imposed accelerations instead of external forces at a node where an element was once connected. The algorithm is implemented into an open-source finite element code, numerically tested using a benchmark structural system with simplified element removal criteria, and able to capture the effect of uncertainty in member capacity. Realistic element removal criteria are introduced for mode-dependent gravity load collapse of seismically deficient and retrofitted reinforced concrete (RC) columns and unreinforced masonry (URM) infill walls. Two applications are conducted using structural systems of RC frames with URM infill walls. The first is a probabilistic study of a one-story model subjected to an ensemble of 14 ground motion recordings from similar neighboring sites during an earthquake event. The study produces empirical probability curves for partial and complete collapse conditioned on different hazard levels, and concludes that the intra-event variability is a major source of uncertainty affecting the outcome of progressive collapse simulations. The second application is a deterministic sensitivity study of progressive collapse response in a five-story structural model to uncertainty in live load, stiffness, damping, and seismic hazard level, subjected to one ground motion record. The analysis identifies the time at incipient collapse as an adequate sensitivity measure, and the uncertainty in ground motion intensity as the most important, followed by the stiffness of the URM infill wall. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198914/abstract

Modeling progressive collapse in reinforced concrete buildings using direct element removal / Mohamed Talaat in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 609-634 Titre : Modeling progressive collapse in reinforced concrete buildings using direct element removal Type de document : texte imprimé Auteurs : Mohamed Talaat, Auteur ; Khalid M. Mosalam, Auteur Article en page(s) : pp. 609-634 Note générale : Génie Civile Langues : Anglais (eng) Mots-clés : Dynamic  analysis;  Element  removal;  Finite  element;  Progressive  collapse;  Reinforced  concrete  frame;  Unreinforced  masonry  infill Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a novel analytical formulation of an element removal algorithm based on dynamic equilibrium and the resulting transient change in system kinematics, by applying imposed accelerations instead of external forces at a node where an element was once connected. The algorithm is implemented into an open-source finite element code, numerically tested using a benchmark structural system with simplified element removal criteria, and able to capture the effect of uncertainty in member capacity. Realistic element removal criteria are introduced for mode-dependent gravity load collapse of seismically deficient and retrofitted reinforced concrete (RC) columns and unreinforced masonry (URM) infill walls. Two applications are conducted using structural systems of RC frames with URM infill walls. The first is a probabilistic study of a one-story model subjected to an ensemble of 14 ground motion recordings from similar neighboring sites during an earthquake event. The study produces empirical probability curves for partial and complete collapse conditioned on different hazard levels, and concludes that the intra-event variability is a major source of uncertainty affecting the outcome of progressive collapse simulations. The second application is a deterministic sensitivity study of progressive collapse response in a five-story structural model to uncertainty in live load, stiffness, damping, and seismic hazard level, subjected to one ground motion record. The analysis identifies the time at incipient collapse as an adequate sensitivity measure, and the uncertainty in ground motion intensity as the most important, followed by the stiffness of the URM infill wall. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198914/abstract [article] Modeling progressive collapse in reinforced concrete buildings using direct element removal [texte imprimé] / Mohamed Talaat, Auteur ; Khalid M. Mosalam, Auteur . - pp. 609-634. Génie Civile Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 609-634 Mots-clés : Dynamic  analysis;  Element  removal;  Finite  element;  Progressive  collapse;  Reinforced  concrete  frame;  Unreinforced  masonry  infill Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : This paper presents a novel analytical formulation of an element removal algorithm based on dynamic equilibrium and the resulting transient change in system kinematics, by applying imposed accelerations instead of external forces at a node where an element was once connected. The algorithm is implemented into an open-source finite element code, numerically tested using a benchmark structural system with simplified element removal criteria, and able to capture the effect of uncertainty in member capacity. Realistic element removal criteria are introduced for mode-dependent gravity load collapse of seismically deficient and retrofitted reinforced concrete (RC) columns and unreinforced masonry (URM) infill walls. Two applications are conducted using structural systems of RC frames with URM infill walls. The first is a probabilistic study of a one-story model subjected to an ensemble of 14 ground motion recordings from similar neighboring sites during an earthquake event. The study produces empirical probability curves for partial and complete collapse conditioned on different hazard levels, and concludes that the intra-event variability is a major source of uncertainty affecting the outcome of progressive collapse simulations. The second application is a deterministic sensitivity study of progressive collapse response in a five-story structural model to uncertainty in live load, stiffness, damping, and seismic hazard level, subjected to one ground motion record. The analysis identifies the time at incipient collapse as an adequate sensitivity measure, and the uncertainty in ground motion intensity as the most important, followed by the stiffness of the URM infill wall. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198914/abstract

High-precision finite element analysis of elastoplastic dynamic responses of super-high-rise steel frames / Makoto Ohsaki in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 635-654 Titre : High-precision finite element analysis of elastoplastic dynamic responses of super-high-rise steel frames Type de document : texte imprimé Auteurs : Makoto Ohsaki, Auteur ; Tomoshi Miyamura, Auteur ; Masayuki Takahashi, Auteur Article en page(s) : pp. 635-654 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Large-scale  structure;  Dynamic  collapse  analysis;  Finite  element  analysis;  E-simulator;  Steel  frame Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new framework is presented for analysis of dynamic collapse behavior of steel frames using large-scale parallel finite element method based on the domain decomposition method. The analysis software is based on ADVC as a part of the E-Simulator that takes advantage of recent development of computer science and high-performance parallel computing in computational mechanics. By making an analysis model with fine meshing, a complicated sequence of local buckling of columns and beams can be simulated. Numerical results are shown for dynamic collapse analysis of single-story and 5-story frame models to show that the global and local behaviors are simultaneously simulated by a high-precision finite element analysis. Eigenvalue analysis is also carried out for a 31-story frame to demonstrate that dynamic analysis can be carried out for a structure discretized to solid elements with more than 70 million DOFs. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198910/abstract [article] High-precision finite element analysis of elastoplastic dynamic responses of super-high-rise steel frames [texte imprimé] / Makoto Ohsaki, Auteur ; Tomoshi Miyamura, Auteur ; Masayuki Takahashi, Auteur . - pp. 635-654. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 635-654 Mots-clés : Large-scale  structure;  Dynamic  collapse  analysis;  Finite  element  analysis;  E-simulator;  Steel  frame Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new framework is presented for analysis of dynamic collapse behavior of steel frames using large-scale parallel finite element method based on the domain decomposition method. The analysis software is based on ADVC as a part of the E-Simulator that takes advantage of recent development of computer science and high-performance parallel computing in computational mechanics. By making an analysis model with fine meshing, a complicated sequence of local buckling of columns and beams can be simulated. Numerical results are shown for dynamic collapse analysis of single-story and 5-story frame models to show that the global and local behaviors are simultaneously simulated by a high-precision finite element analysis. Eigenvalue analysis is also carried out for a 31-story frame to demonstrate that dynamic analysis can be carried out for a structure discretized to solid elements with more than 70 million DOFs. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122198910/abstract

Numerical collapse simulation of large-scale structural systems using an optimization-based algorithm / Sivaselvan, Mettupalayam V. in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 655-677 Titre : Numerical collapse simulation of large-scale structural systems using an optimization-based algorithm Type de document : texte imprimé Auteurs : Sivaselvan, Mettupalayam V., Auteur ; Oren Lavan, Auteur ; Dargush, G. F., Auteur Article en page(s) : pp. 655-677 Note générale : Génie Cicil Langues : Anglais (eng) Mots-clés : nonlinear  dynamic  simulation  •  convex  optimization  •  generalized  standard  material  •  stored  energy  •  dissipation  potential  •  mixed  Lagrangian  formalism Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new algorithm for nonlinear dynamic simulation of structures is presented. The algorithm is based on a mixed Lagrangian approach described by Sivaselvan and Reinhorn (J. Eng. Mech. (ASCE) 2006; 132(8):795-805). The algorithm developed in this paper is for the simulation of large-scale structural systems. The algorithm is applicable to a wide class of structural systems whose constituent material or component behavior can be derived from a stored energy function and a dissipation potential. The algorithm is based on the fact that for such systems, when using a certain class of time-discretization schemes to numerically compute the system response, the incremental problem of computing the system state at the next sample time knowing the current state and the input is one of convex minimization. As a result, the algorithm possesses excellent convergence characteristics. It is also applicable to geometric nonlinear problems. The implementation of the algorithm is described, and its applicability to the collapse analysis of large-scale structures is demonstrated through numerical examples. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121676918/abstract [article] Numerical collapse simulation of large-scale structural systems using an optimization-based algorithm [texte imprimé] / Sivaselvan, Mettupalayam V., Auteur ; Oren Lavan, Auteur ; Dargush, G. F., Auteur . - pp. 655-677. Génie Cicil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 655-677 Mots-clés : nonlinear  dynamic  simulation  •  convex  optimization  •  generalized  standard  material  •  stored  energy  •  dissipation  potential  •  mixed  Lagrangian  formalism Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new algorithm for nonlinear dynamic simulation of structures is presented. The algorithm is based on a mixed Lagrangian approach described by Sivaselvan and Reinhorn (J. Eng. Mech. (ASCE) 2006; 132(8):795-805). The algorithm developed in this paper is for the simulation of large-scale structural systems. The algorithm is applicable to a wide class of structural systems whose constituent material or component behavior can be derived from a stored energy function and a dissipation potential. The algorithm is based on the fact that for such systems, when using a certain class of time-discretization schemes to numerically compute the system response, the incremental problem of computing the system state at the next sample time knowing the current state and the input is one of convex minimization. As a result, the algorithm possesses excellent convergence characteristics. It is also applicable to geometric nonlinear problems. The implementation of the algorithm is described, and its applicability to the collapse analysis of large-scale structures is demonstrated through numerical examples. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121676918/abstract

Performance evaluation of a nonlinear Winkler-based shallow foundation model using centrifuge test results / Prishati Raychowdhury in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 679-698 Titre : Performance evaluation of a nonlinear Winkler-based shallow foundation model using centrifuge test results Type de document : texte imprimé Auteurs : Prishati Raychowdhury, Auteur ; Hutchinson, Tara C., Auteur Article en page(s) : pp. 679-698 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Shallow  foundation;  Centrifuge  tests;  BNWF  modeling;  Nonlinear  analysis Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : When a structure supported on shallow foundations is subjected to inertial loading due to earthquake motions, the foundation may undergo sliding, settling and rocking movements. Even if the capacity of the foundation is mobilized, the soil-foundation interface may dissipate significant amounts of vibrational energy, resulting in reduced force demands to the superstructure. If the capacity is not mobilized, these movements introduce additional flexibility to the system, which may shift its period away from the potentially hazardous zone of response spectra for most earthquake ground motions. In either case, transient and permanent deformations will need to be accounted for. To consider the aforementioned benefits and consequences in performance-based seismic design, robust and reliable numerical modeling tools are needed. In this article, a Winkler-based modeling framework is proposed to address this issue. The model includes a distributed array of mechanistic nonlinear inelastic springs, dashpots, and gap elements, with backbone curves of the nonlinear springs calibrated against shallow foundation experiments. Model evaluation is conducted by simulating the response of a number of centrifuge experiments. Experiments considered include square and strip footings, bridge and building models, static and dynamic loading, footings on sand and clay, a range of static vertical factors of safety, and a range of aspect ratios. It is observed that the model can reasonably predict measured footing response in terms of moment, shear, settlement and rotational demands. In addition, the general hysteresis shape of the moment-rotation, settlement-rotation and shear-sliding curves is reasonably captured. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122246967/abstract [article] Performance evaluation of a nonlinear Winkler-based shallow foundation model using centrifuge test results [texte imprimé] / Prishati Raychowdhury, Auteur ; Hutchinson, Tara C., Auteur . - pp. 679-698. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 679-698 Mots-clés : Shallow  foundation;  Centrifuge  tests;  BNWF  modeling;  Nonlinear  analysis Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : When a structure supported on shallow foundations is subjected to inertial loading due to earthquake motions, the foundation may undergo sliding, settling and rocking movements. Even if the capacity of the foundation is mobilized, the soil-foundation interface may dissipate significant amounts of vibrational energy, resulting in reduced force demands to the superstructure. If the capacity is not mobilized, these movements introduce additional flexibility to the system, which may shift its period away from the potentially hazardous zone of response spectra for most earthquake ground motions. In either case, transient and permanent deformations will need to be accounted for. To consider the aforementioned benefits and consequences in performance-based seismic design, robust and reliable numerical modeling tools are needed. In this article, a Winkler-based modeling framework is proposed to address this issue. The model includes a distributed array of mechanistic nonlinear inelastic springs, dashpots, and gap elements, with backbone curves of the nonlinear springs calibrated against shallow foundation experiments. Model evaluation is conducted by simulating the response of a number of centrifuge experiments. Experiments considered include square and strip footings, bridge and building models, static and dynamic loading, footings on sand and clay, a range of static vertical factors of safety, and a range of aspect ratios. It is observed that the model can reasonably predict measured footing response in terms of moment, shear, settlement and rotational demands. In addition, the general hysteresis shape of the moment-rotation, settlement-rotation and shear-sliding curves is reasonably captured. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122246967/abstract

Time domain simulation of soil-foundation-structure interaction in non-uniform soils / Jeremic, Boris in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 699-718 Titre : Time domain simulation of soil-foundation-structure interaction in non-uniform soils Type de document : texte imprimé Auteurs : Jeremic, Boris, Auteur ; Guanzhou Jie, Auteur ; Matthias Preisig, Auteur Article en page(s) : pp. 699-718 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Time  domain;  Earthquake  soil-foundation-structure  interaction  ;  Parallel  computing;  Finite  elements;  High-fidelity  SSI  models Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Presented here is a numerical investigation of the influence of non-uniform soil conditions on a prototype concrete bridge with three bents (four span) where soil beneath bridge bents are varied between stiff sands and soft clay. A series of high-fidelity models of the soil-foundation-structure system were developed and described in some details. Development of a series of high-fidelity models was required to properly simulate seismic wave propagation (frequency up to 10Hz) through highly nonlinear, elastic plastic soil, piles and bridge structure. Eight specific cases representing combinations of different soil conditions beneath each of the bents are simulated. It is shown that variability of soil beneath bridge bents has significant influence on bridge system (soil-foundation-structure) seismic behavior. Results also indicate that free field motions differ quite a bit from what is observed (simulated) under at the base of the bridge columns indicating that use of free field motions as input for only structural models might not be appropriate. In addition to that, it is also shown that usually assumed beneficial effect of stiff soils underneath a structure (bridge) cannot be generalized and that such stiff soils do not necessarily help seismic performance of structures. Moreover, it is shown that dynamic characteristics of all three components of a triad made up of earthquake, soil and structure play crucial role in determining the seismic performance of the infrastructure (bridge) system. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122197605/abstract [article] Time domain simulation of soil-foundation-structure interaction in non-uniform soils [texte imprimé] / Jeremic, Boris, Auteur ; Guanzhou Jie, Auteur ; Matthias Preisig, Auteur . - pp. 699-718. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 699-718 Mots-clés : Time  domain;  Earthquake  soil-foundation-structure  interaction  ;  Parallel  computing;  Finite  elements;  High-fidelity  SSI  models Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Presented here is a numerical investigation of the influence of non-uniform soil conditions on a prototype concrete bridge with three bents (four span) where soil beneath bridge bents are varied between stiff sands and soft clay. A series of high-fidelity models of the soil-foundation-structure system were developed and described in some details. Development of a series of high-fidelity models was required to properly simulate seismic wave propagation (frequency up to 10Hz) through highly nonlinear, elastic plastic soil, piles and bridge structure. Eight specific cases representing combinations of different soil conditions beneath each of the bents are simulated. It is shown that variability of soil beneath bridge bents has significant influence on bridge system (soil-foundation-structure) seismic behavior. Results also indicate that free field motions differ quite a bit from what is observed (simulated) under at the base of the bridge columns indicating that use of free field motions as input for only structural models might not be appropriate. In addition to that, it is also shown that usually assumed beneficial effect of stiff soils underneath a structure (bridge) cannot be generalized and that such stiff soils do not necessarily help seismic performance of structures. Moreover, it is shown that dynamic characteristics of all three components of a triad made up of earthquake, soil and structure play crucial role in determining the seismic performance of the infrastructure (bridge) system. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122197605/abstract

Nonlinear stochastic dynamic analysis for performance-based earthquake engineering / Der Kiureghian, Armen in Earthquake engineering structural dynamics, Vol. 38 N°5 (Avril 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 719-738 Titre : Nonlinear stochastic dynamic analysis for performance-based earthquake engineering Type de document : texte imprimé Auteurs : Der Kiureghian, Armen, Auteur ; Takita, Kazuya, Auteur Article en page(s) : pp. 719-738 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Equivalent  linearization;  Fragility  curve;  Nonlinear  response  •  Seismic  demand;  Stochastic  dynamics;  Tail  probability Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new approach for computing seismic fragility curves for nonlinear structures for use in performance-based earthquake engineering analysis is proposed. The approach makes use of a recently developed method for nonlinear stochastic dynamic analysis by tail-equivalent linearization. The ground motion is modeled as a discretized stochastic process with a set of parameters that characterizes its evolutionary intensity and frequency content. For each selected response (seismic demand) threshold, a linear system is defined that has the same tail probability as the nonlinear response in first-order approximation. Simple linear random vibration analysis with the tail-equivalent linear system then yields the fragility curve. The approach has the advantage of avoiding the selection and scaling of recorded accelerograms and repeated time-history analyses, which is the current practice for developing fragility curves. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122205256/abstract [article] Nonlinear stochastic dynamic analysis for performance-based earthquake engineering [texte imprimé] / Der Kiureghian, Armen, Auteur ; Takita, Kazuya, Auteur . - pp. 719-738. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N°5 (Avril 2009) . - pp. 719-738 Mots-clés : Equivalent  linearization;  Fragility  curve;  Nonlinear  response  •  Seismic  demand;  Stochastic  dynamics;  Tail  probability Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A new approach for computing seismic fragility curves for nonlinear structures for use in performance-based earthquake engineering analysis is proposed. The approach makes use of a recently developed method for nonlinear stochastic dynamic analysis by tail-equivalent linearization. The ground motion is modeled as a discretized stochastic process with a set of parameters that characterizes its evolutionary intensity and frequency content. For each selected response (seismic demand) threshold, a linear system is defined that has the same tail probability as the nonlinear response in first-order approximation. Simple linear random vibration analysis with the tail-equivalent linear system then yields the fragility curve. The approach has the advantage of avoiding the selection and scaling of recorded accelerograms and repeated time-history analyses, which is the current practice for developing fragility curves. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/122205256/abstract

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