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

Influence of structural design on the aeroelastic stability of brancusi 's endless column / R. D. Gabbai in Journal of engineering mechanics, Vol. 134 n°6 (Juin 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 n°6 (Juin 2008) . - pp. 462–465. Titre : Influence of structural design on the aeroelastic stability of brancusi 's endless column Type de document : texte imprimé Auteurs : R. D. Gabbai, Auteur Année de publication : 2008 Article en page(s) : pp. 462–465. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Aeroelasticity  Vortex  shedding  Wind  loads  Structural  engineering  Columns Résumé : Brancusi’s Endless Column (Târgu-Jiu, Romania) is an interesting case study in bluff body aeroelasticity. It has been referred to as aeroelastically indifferent owing to its remarkable aeroelastic stability. This stability has been attributed to its unconventional shape. Calculations are presented which show that this strictly aerodynamic view of the column behavior is incomplete, and that the structural dynamics characteristics of the column have a powerful role in ensuring its aeroelastic stability. The calculations show that the column’s design, which provided for significant damping and mass, would assure its aeroelastic stability even if the column had a conventional and aeroelastically less favorable shape, i.e., if it were a circular cylinder (a shape that is unfavorable from the point of view of vortex-induced response) or a square cylinder (a shape that is unfavorable from the point of view of galloping). ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A6%2846 [...] [article] Influence of structural design on the aeroelastic stability of brancusi 's endless column [texte imprimé] / R. D. Gabbai, Auteur . - 2008 . - pp. 462–465. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 n°6 (Juin 2008) . - pp. 462–465. Mots-clés : Aeroelasticity  Vortex  shedding  Wind  loads  Structural  engineering  Columns Résumé : Brancusi’s Endless Column (Târgu-Jiu, Romania) is an interesting case study in bluff body aeroelasticity. It has been referred to as aeroelastically indifferent owing to its remarkable aeroelastic stability. This stability has been attributed to its unconventional shape. Calculations are presented which show that this strictly aerodynamic view of the column behavior is incomplete, and that the structural dynamics characteristics of the column have a powerful role in ensuring its aeroelastic stability. The calculations show that the column’s design, which provided for significant damping and mass, would assure its aeroelastic stability even if the column had a conventional and aeroelastically less favorable shape, i.e., if it were a circular cylinder (a shape that is unfavorable from the point of view of vortex-induced response) or a square cylinder (a shape that is unfavorable from the point of view of galloping). ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A6%2846 [...]