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Accounting for ground-motion spectral shape characteristics in structural collapse assessment through an adjustment for epsilon / Curt B. Haselton in Journal of structural engineering, Vol. 137 N° 3 (Mars 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 3 (Mars 2011) . - pp. 332-344 Titre : Accounting for ground-motion spectral shape characteristics in structural collapse assessment through an adjustment for epsilon Type de document : texte imprimé Auteurs : Curt B. Haselton, Auteur ; Jack W. Baker, Auteur ; Abbie B. Liel, Auteur Année de publication : 2011 Article en page(s) : pp. 332-344 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Ground  motions  Spectral  shape  Epsilon  Collapse  assessment  Performance  assessment  ATC-63  FEMA  P695 Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : One of the challenges of assessing structural collapse performance is the appropriate selection of ground motions for use in the nonlinear dynamic collapse simulation. The ground motions should represent characteristics of extreme ground motions that exceed the ground-motion intensities considered in the original building design. For modern buildings in the western United States, ground motions that cause collapse are expected to be rare high-intensity motions associated with a large magnitude earthquake. Recent research has shown that rare high-intensity ground motions have a peaked spectral shape that should be considered in ground-motion selection and scaling. One method to account for this spectral shape effect is through the selection of a set of ground motions that is specific to the building’s fundamental period and the site hazard characteristics. This selection presents a significant challenge when assessing the collapse capacity of a large number of buildings or for developing systematic procedures because it implies the need to assemble specific ground-motion sets for each building. This paper proposes an alternative method, whereby a general set of far-field ground motions is used for collapse simulation, and the resulting collapse capacity is adjusted to account for the spectral shape effects that are not reflected in the ground-motion selection. The simplified method is compared with the more direct record selection strategy, and results of the two approaches show good agreement. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i3/p332_s1?isAuthorized=no [article] Accounting for ground-motion spectral shape characteristics in structural collapse assessment through an adjustment for epsilon [texte imprimé] / Curt B. Haselton, Auteur ; Jack W. Baker, Auteur ; Abbie B. Liel, Auteur . - 2011 . - pp. 332-344. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 3 (Mars 2011) . - pp. 332-344 Mots-clés : Ground  motions  Spectral  shape  Epsilon  Collapse  assessment  Performance  assessment  ATC-63  FEMA  P695 Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : One of the challenges of assessing structural collapse performance is the appropriate selection of ground motions for use in the nonlinear dynamic collapse simulation. The ground motions should represent characteristics of extreme ground motions that exceed the ground-motion intensities considered in the original building design. For modern buildings in the western United States, ground motions that cause collapse are expected to be rare high-intensity motions associated with a large magnitude earthquake. Recent research has shown that rare high-intensity ground motions have a peaked spectral shape that should be considered in ground-motion selection and scaling. One method to account for this spectral shape effect is through the selection of a set of ground motions that is specific to the building’s fundamental period and the site hazard characteristics. This selection presents a significant challenge when assessing the collapse capacity of a large number of buildings or for developing systematic procedures because it implies the need to assemble specific ground-motion sets for each building. This paper proposes an alternative method, whereby a general set of far-field ground motions is used for collapse simulation, and the resulting collapse capacity is adjusted to account for the spectral shape effects that are not reflected in the ground-motion selection. The simplified method is compared with the more direct record selection strategy, and results of the two approaches show good agreement. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i3/p332_s1?isAuthorized=no

Evaluation of the seismic performance of a code-conforming reinforced-concrete frame building - from seismic hazard to collapse safety and economic losses / Christine A. Goulet in Earthquake engineering structural dynamics, Vol. 36 N°13 (Novembre 2007) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 36 N°13 (Novembre 2007) . - 1973-1997 p. Titre : Evaluation of the seismic performance of a code-conforming reinforced-concrete frame building - from seismic hazard to collapse safety and economic losses Type de document : texte imprimé Auteurs : Christine A. Goulet, Auteur ; Curt B. Haselton, Auteur ; Judith Mitrani-Reiser, Auteur Article en page(s) : 1973-1997 p. Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : seismic  performance  assessment  building  epsilon  collapse  lossesSismique  Performances  Évaluation  Bâtiment  Epsilon  PertesEffondrement Résumé : A state-of-the-art seismic performance assessment is illustrated through application to a reinforced-concrete moment-frame building designed per current (2003) building code provisions. Performance is quantified in terms of economic losses and collapse safety. The assessment includes site-specific seismic hazard analyses, nonlinear dynamic structural response simulations to collapse, damage analyses, and loss estimation. When selecting ground motion records for nonlinear dynamic analyses that are consistent with a target hazard level expressed in terms of a response spectral value at the building's fundamental period, it is important to consider the response spectral shape, especially when considering higher hazard levels. This was done through the parameter commonly denoted by . Neglecting these effects during record selection is shown to lead to a factor of 5-10 overestimation of mean annual collapse rate. Structural response simulations, which properly account for uncertainties in ground motions and structural modelling, indicate a 2-7% probability of collapse for buildings subjected to motions scaled to a hazard level equivalent to a 2% probability of exceedance in 50 years. The probabilities of component damage and the means and coefficients of variation of the repair costs are calculated using fragility functions and repair-cost probability distributions. The calculated expected annual losses for various building design variants range from 0.6 to 1.1% of the replacement value, where the smaller losses are for above-code design variants and the larger losses are for buildings designed with minimum-code compliance. Sensitivity studies highlight the impact of key modelling assumptions on the accurate calculation of damage and the associated repair costs. Un état de l'art sismique évaluation de la performance est illustrée par l'application d'un cadre en béton armé instant bâtiment conçu par actuelle (2003) des dispositions du code du bâtiment. La performance est quantifiée en termes de pertes économiques et de l'effondrement de sécurité. L'évaluation comprend des sites spécifiques risque sismique analyses dynamiques non linéaires réponse structurelle à l'effondrement des simulations, des analyses des dommages et pertes d'estimation. Lors de la sélection des mouvements de dossiers pour des analyses dynamiques non linéaires qui sont compatibles avec un niveau de risque cible exprimée en termes de la réponse spectrale de valeur à la période fondamentale de la construction, il est important de considérer la réponse spectrale de la forme, en particulier lors de l'examen des niveaux de risque plus élevé. Cela s'est fait par l'intermédiaire du paramètre couramment signalés par. Négliger ces effets pendant la sélection d'enregistrements est affichée pour aboutir à un facteur de 5-10 surestimation de la moyenne annuelle des taux d'effondrement. Réponse structurelle des simulations, qui bien tenir compte des incertitudes dans les mouvements au sol et la modélisation structurelle, 2-7% indiquent une probabilité de l'effondrement des bâtiments soumis à des motions de l'échelle à un niveau de risque équivalent à 2% de probabilité de dépassement en 50 ans. Les probabilités de dommages et de la composante des moyens et des coefficients de variation des coûts de réparation sont calculées en utilisant la fragilité des fonctions et des coûts de réparation distributions de probabilités. Le calculé les pertes annuelles attendues pour différentes variantes de la conception des bâtiments varient de 0,6 à 1,1% de la valeur de remplacement, où les pertes sont plus petits pour le code ci-dessus et de concevoir des variantes les plus grandes pertes sont conçus pour les bâtiments, avec un minimum de code de la conformité. Sensibilité études mettent en lumière l'impact de la modélisation des hypothèses clés sur le calcul précis des dommages et les frais de réparation. DEWEY : 551.2 ISSN : 0098-8847 RAMEAU : Génie parasismique En ligne : http://www3.interscience.wiley.com/cgi-bin/abstract/114280160/ABSTRACT [article] Evaluation of the seismic performance of a code-conforming reinforced-concrete frame building - from seismic hazard to collapse safety and economic losses [texte imprimé] / Christine A. Goulet, Auteur ; Curt B. Haselton, Auteur ; Judith Mitrani-Reiser, Auteur . - 1973-1997 p. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 36 N°13 (Novembre 2007) . - 1973-1997 p. Mots-clés : seismic  performance  assessment  building  epsilon  collapse  lossesSismique  Performances  Évaluation  Bâtiment  Epsilon  PertesEffondrement Résumé : A state-of-the-art seismic performance assessment is illustrated through application to a reinforced-concrete moment-frame building designed per current (2003) building code provisions. Performance is quantified in terms of economic losses and collapse safety. The assessment includes site-specific seismic hazard analyses, nonlinear dynamic structural response simulations to collapse, damage analyses, and loss estimation. When selecting ground motion records for nonlinear dynamic analyses that are consistent with a target hazard level expressed in terms of a response spectral value at the building's fundamental period, it is important to consider the response spectral shape, especially when considering higher hazard levels. This was done through the parameter commonly denoted by . Neglecting these effects during record selection is shown to lead to a factor of 5-10 overestimation of mean annual collapse rate. Structural response simulations, which properly account for uncertainties in ground motions and structural modelling, indicate a 2-7% probability of collapse for buildings subjected to motions scaled to a hazard level equivalent to a 2% probability of exceedance in 50 years. The probabilities of component damage and the means and coefficients of variation of the repair costs are calculated using fragility functions and repair-cost probability distributions. The calculated expected annual losses for various building design variants range from 0.6 to 1.1% of the replacement value, where the smaller losses are for above-code design variants and the larger losses are for buildings designed with minimum-code compliance. Sensitivity studies highlight the impact of key modelling assumptions on the accurate calculation of damage and the associated repair costs. Un état de l'art sismique évaluation de la performance est illustrée par l'application d'un cadre en béton armé instant bâtiment conçu par actuelle (2003) des dispositions du code du bâtiment. La performance est quantifiée en termes de pertes économiques et de l'effondrement de sécurité. L'évaluation comprend des sites spécifiques risque sismique analyses dynamiques non linéaires réponse structurelle à l'effondrement des simulations, des analyses des dommages et pertes d'estimation. Lors de la sélection des mouvements de dossiers pour des analyses dynamiques non linéaires qui sont compatibles avec un niveau de risque cible exprimée en termes de la réponse spectrale de valeur à la période fondamentale de la construction, il est important de considérer la réponse spectrale de la forme, en particulier lors de l'examen des niveaux de risque plus élevé. Cela s'est fait par l'intermédiaire du paramètre couramment signalés par. Négliger ces effets pendant la sélection d'enregistrements est affichée pour aboutir à un facteur de 5-10 surestimation de la moyenne annuelle des taux d'effondrement. Réponse structurelle des simulations, qui bien tenir compte des incertitudes dans les mouvements au sol et la modélisation structurelle, 2-7% indiquent une probabilité de l'effondrement des bâtiments soumis à des motions de l'échelle à un niveau de risque équivalent à 2% de probabilité de dépassement en 50 ans. Les probabilités de dommages et de la composante des moyens et des coefficients de variation des coûts de réparation sont calculées en utilisant la fragilité des fonctions et des coûts de réparation distributions de probabilités. Le calculé les pertes annuelles attendues pour différentes variantes de la conception des bâtiments varient de 0,6 à 1,1% de la valeur de remplacement, où les pertes sont plus petits pour le code ci-dessus et de concevoir des variantes les plus grandes pertes sont conçus pour les bâtiments, avec un minimum de code de la conformité. Sensibilité études mettent en lumière l'impact de la modélisation des hypothèses clés sur le calcul précis des dommages et les frais de réparation. DEWEY : 551.2 ISSN : 0098-8847 RAMEAU : Génie parasismique En ligne : http://www3.interscience.wiley.com/cgi-bin/abstract/114280160/ABSTRACT

Seismic collapse safety of reinforced concrete buildings. I, Assessment of ductile moment frames / Curt B. Haselton in Journal of structural engineering, Vol. 137 N° 4 (Avril 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 4 (Avril 2011) . - pp. 481-491 Titre : Seismic collapse safety of reinforced concrete buildings. I, Assessment of ductile moment frames Type de document : texte imprimé Auteurs : Curt B. Haselton, Auteur ; Abbie B. Liel, Auteur ; Gregory G. Deierlein, Auteur Année de publication : 2011 Article en page(s) : pp. 481-491 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Collapse  Earthquake  engineerin  Seismic  effects  Reinforced  concrete  structures  Structural  reliability Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study applies nonlinear dynamic analyses to assess the risk of collapse of RC special moment-frame (SMF) buildings to quantify the seismic safety implied by modern building codes. Thirty archetypical RC SMF buildings, ranging in height from 1 to 20 stories, are designed according to ASCE 7-02 and ACI 318-05 for a high-seismic region. The results of performance-based seismic assessments show that, on average, these buildings have an 11% probability of collapse under ground motion intensities with a 2% probability of exceedance in 50 years. The average mean annual rate of collapse of 3.1×10-4 collapses per year corresponds to an average of 1.5% probability of collapse in 50 years. The study further examines the influence of specific design provisions on collapse safety. In particular, changes to the minimum seismic base shear requirement between 2002 and 2005 editions of ASCE 7 and variations in ACI 318 strong-column weak-beam (SCWB) design requirements are investigated. The study finds that the reduction in the minimum base shear, introduced in ASCE 7-05 and subsequently rescinded, dramatically increases the collapse risk of tall (long-period) frame buildings in high-seismic regions. An investigation of the SCWB requirements shows that the current ACI 318 provisions delay, but do not prevent, column yielding and the formation of story collapse mechanisms. An increase in the SCWB ratio above 6/5 (1.2) does not significantly improve performance of low-rise frame buildings but may reduce collapse risk for midrise and taller buildings. This study of modern RC buildings is contrasted with the collapse safety of older (nonductile) RC moment-frame buildings in the companion paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i4/p481_s1?isAuthorized=no [article] Seismic collapse safety of reinforced concrete buildings. I, Assessment of ductile moment frames [texte imprimé] / Curt B. Haselton, Auteur ; Abbie B. Liel, Auteur ; Gregory G. Deierlein, Auteur . - 2011 . - pp. 481-491. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 4 (Avril 2011) . - pp. 481-491 Mots-clés : Collapse  Earthquake  engineerin  Seismic  effects  Reinforced  concrete  structures  Structural  reliability Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study applies nonlinear dynamic analyses to assess the risk of collapse of RC special moment-frame (SMF) buildings to quantify the seismic safety implied by modern building codes. Thirty archetypical RC SMF buildings, ranging in height from 1 to 20 stories, are designed according to ASCE 7-02 and ACI 318-05 for a high-seismic region. The results of performance-based seismic assessments show that, on average, these buildings have an 11% probability of collapse under ground motion intensities with a 2% probability of exceedance in 50 years. The average mean annual rate of collapse of 3.1×10-4 collapses per year corresponds to an average of 1.5% probability of collapse in 50 years. The study further examines the influence of specific design provisions on collapse safety. In particular, changes to the minimum seismic base shear requirement between 2002 and 2005 editions of ASCE 7 and variations in ACI 318 strong-column weak-beam (SCWB) design requirements are investigated. The study finds that the reduction in the minimum base shear, introduced in ASCE 7-05 and subsequently rescinded, dramatically increases the collapse risk of tall (long-period) frame buildings in high-seismic regions. An investigation of the SCWB requirements shows that the current ACI 318 provisions delay, but do not prevent, column yielding and the formation of story collapse mechanisms. An increase in the SCWB ratio above 6/5 (1.2) does not significantly improve performance of low-rise frame buildings but may reduce collapse risk for midrise and taller buildings. This study of modern RC buildings is contrasted with the collapse safety of older (nonductile) RC moment-frame buildings in the companion paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i4/p481_s1?isAuthorized=no

Seismic collapse safety of reinforced concrete buildings. II, Comparative assessment of nonductile and ductile moment frames / Abbie B. Liel in Journal of structural engineering, Vol. 137 N° 4 (Avril 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 4 (Avril 2011) . - pp. 492-502 Titre : Seismic collapse safety of reinforced concrete buildings. II, Comparative assessment of nonductile and ductile moment frames Type de document : texte imprimé Auteurs : Abbie B. Liel, Auteur ; Curt B. Haselton, Auteur ; Gregory G. Deierlein, Auteur Année de publication : 2011 Article en page(s) : pp. 492-502 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Collapse  Earthquake  engineering  Structural  reliability  Reinforced  concrete  structures  Buildings  Commercial  Seismic  effects Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study is the second of two companion papers to examine the seismic collapse safety of reinforced concrete frame buildings, and examines nonductile moment frames that are representative of those built before the mid-1970s in California. The probabilistic assessment relies on nonlinear dynamic simulation of structural response to calculate the collapse risk, accounting for uncertainties in ground-motion characteristics and structural modeling. The evaluation considers a set of archetypical nonductile RC frame structures of varying height that are designed according to the seismic provisions of the 1967 Uniform Building Code. The results indicate that nonductile RC frame structures have a mean annual frequency of collapse ranging from 5 to 14×10-3 at a typical high-seismic California site, which is approximately 40 times higher than corresponding results for modern code-conforming special RC moment frames. These metrics demonstrate the effectiveness of ductile detailing and capacity design requirements, which have been introduced over the past 30 years to improve the safety of RC buildings. Data on comparative safety between nonductile and ductile frames may also inform the development of policies for appraising and mitigating seismic collapse risk of existing RC frame buildings. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i4/p492_s1?isAuthorized=no [article] Seismic collapse safety of reinforced concrete buildings. II, Comparative assessment of nonductile and ductile moment frames [texte imprimé] / Abbie B. Liel, Auteur ; Curt B. Haselton, Auteur ; Gregory G. Deierlein, Auteur . - 2011 . - pp. 492-502. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 4 (Avril 2011) . - pp. 492-502 Mots-clés : Collapse  Earthquake  engineering  Structural  reliability  Reinforced  concrete  structures  Buildings  Commercial  Seismic  effects Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study is the second of two companion papers to examine the seismic collapse safety of reinforced concrete frame buildings, and examines nonductile moment frames that are representative of those built before the mid-1970s in California. The probabilistic assessment relies on nonlinear dynamic simulation of structural response to calculate the collapse risk, accounting for uncertainties in ground-motion characteristics and structural modeling. The evaluation considers a set of archetypical nonductile RC frame structures of varying height that are designed according to the seismic provisions of the 1967 Uniform Building Code. The results indicate that nonductile RC frame structures have a mean annual frequency of collapse ranging from 5 to 14×10-3 at a typical high-seismic California site, which is approximately 40 times higher than corresponding results for modern code-conforming special RC moment frames. These metrics demonstrate the effectiveness of ductile detailing and capacity design requirements, which have been introduced over the past 30 years to improve the safety of RC buildings. Data on comparative safety between nonductile and ductile frames may also inform the development of policies for appraising and mitigating seismic collapse risk of existing RC frame buildings. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i4/p492_s1?isAuthorized=no