Documents disponibles écrits par cet auteur

Aerodynamic damping in the along-wind response of tall buildings / R. D. Gabbai in Journal of structural engineering, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 117-119 Titre : Aerodynamic damping in the along-wind response of tall buildings Type de document : texte imprimé Auteurs : R. D. Gabbai, Auteur ; E. Simiu, Auteur Année de publication : 2011 Article en page(s) : pp. 117-119 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Aerodynamics  Damping  Building  technology  Flexible  buildings  Structural  dynamics  Wind  forces Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : We present a novel methodology for the estimation of the aerodynamic damping that affects the along-wind response of tall buildings. The estimation uses (1) measurements of the external pressures on the windward and leeward faces under wind normal to a building face; (2) a simplified model of the relation between those pressures and the longitudinal fluctuating velocities with respect to the building; and (3) time-domain estimates of the along-wind building response that preserve the phase relationships between pressures and response. The methodology accounts explicitly for the shapes of the building’s modes of vibration, the natural frequencies of vibration, and the mechanical damping ratios, and takes advantage of the recent development of efficient time-domain algorithms for calculating dynamic structural response to wind. The methodology is applied to an isolated tall building in suburban terrain. The results of the calculations show that, for the example being considered, the aerodynamic damping (1) is positive, that is, it has a favorable effect; (2) is small relative to the mechanical damping; (3) is for practical purposes independent of the shape of the fundamental mode of vibration; and (4) is unaffected by higher vibration modes. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p117_s1?isAuthorized=no [article] Aerodynamic damping in the along-wind response of tall buildings [texte imprimé] / R. D. Gabbai, Auteur ; E. Simiu, Auteur . - 2011 . - pp. 117-119. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 117-119 Mots-clés : Aerodynamics  Damping  Building  technology  Flexible  buildings  Structural  dynamics  Wind  forces Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : We present a novel methodology for the estimation of the aerodynamic damping that affects the along-wind response of tall buildings. The estimation uses (1) measurements of the external pressures on the windward and leeward faces under wind normal to a building face; (2) a simplified model of the relation between those pressures and the longitudinal fluctuating velocities with respect to the building; and (3) time-domain estimates of the along-wind building response that preserve the phase relationships between pressures and response. The methodology accounts explicitly for the shapes of the building’s modes of vibration, the natural frequencies of vibration, and the mechanical damping ratios, and takes advantage of the recent development of efficient time-domain algorithms for calculating dynamic structural response to wind. The methodology is applied to an isolated tall building in suburban terrain. The results of the calculations show that, for the example being considered, the aerodynamic damping (1) is positive, that is, it has a favorable effect; (2) is small relative to the mechanical damping; (3) is for practical purposes independent of the shape of the fundamental mode of vibration; and (4) is unaffected by higher vibration modes. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p117_s1?isAuthorized=no

Tall building response parameters / J. J. Filliben in Journal of structural engineering, Vol. 136 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 2 (Fevrier 2010) . - pp. 160-164 Titre : Tall building response parameters : sensitivity study based on orthogonal factorial experiment design technique Type de document : texte imprimé Auteurs : J. J. Filliben, Auteur ; E. Simiu, Auteur Année de publication : 2011 Article en page(s) : pp. 160-164 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Damping  Structural  design  Frequency  Buildings  high-rise  Wind  speed Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This work has two objectives. The first objective is to introduce structural engineers to the experiment design technique, whose future applications may include, for example, the total response of tall buildings, the strength reserve of statically indeterminate structures with nonlinear behavior, for which the duration of each run is large, and the aerodynamic response of a structure under a flow with a variety of simulated flow parameters. The second objective is to show, by using the experiment design technique, that wind load factors for tall buildings depend significantly upon uncertainties with respect to the natural frequencies of vibration and the damping ratios. Because this dependence is disregarded in the ASCE 7-05 Standard, wind load factors specified therein can lead to safety levels that are significantly lower for flexible buildings than for rigid buildings. An unexpected result of the study is that estimates of wind effects based on peak gust speeds entail nonnegligible errors. Consideration should therefore be given to replacing peak gust speeds by sustained wind speeds. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i2/p160_s1?isAuthorized=no [article] Tall building response parameters : sensitivity study based on orthogonal factorial experiment design technique [texte imprimé] / J. J. Filliben, Auteur ; E. Simiu, Auteur . - 2011 . - pp. 160-164. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 2 (Fevrier 2010) . - pp. 160-164 Mots-clés : Damping  Structural  design  Frequency  Buildings  high-rise  Wind  speed Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This work has two objectives. The first objective is to introduce structural engineers to the experiment design technique, whose future applications may include, for example, the total response of tall buildings, the strength reserve of statically indeterminate structures with nonlinear behavior, for which the duration of each run is large, and the aerodynamic response of a structure under a flow with a variety of simulated flow parameters. The second objective is to show, by using the experiment design technique, that wind load factors for tall buildings depend significantly upon uncertainties with respect to the natural frequencies of vibration and the damping ratios. Because this dependence is disregarded in the ASCE 7-05 Standard, wind load factors specified therein can lead to safety levels that are significantly lower for flexible buildings than for rigid buildings. An unexpected result of the study is that estimates of wind effects based on peak gust speeds entail nonnegligible errors. Consideration should therefore be given to replacing peak gust speeds by sustained wind speeds. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i2/p160_s1?isAuthorized=no