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Engineered bamboo I-joists / Mark Aschheim in Journal of structural engineering, Vol. 136 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 12 (Décembre 2010) . - pp. 1619-1624 Titre : Engineered bamboo I-joists Type de document : texte imprimé Auteurs : Mark Aschheim, Auteur ; Luisa María Gil-Martín, Auteur ; Enrique Hernandez-Montes, Auteur Année de publication : 2011 Article en page(s) : pp. 1619-1624 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bamboo  I-joists  Flexural  strength  Shear  strength  Stiffness  Design  values  Sustainable  materials  Rapidly  renewable  materials Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Many bamboo species are well regarded for their strength and rapid renewability, although the nonuniformity of bamboo poles has impeded use in developed countries. Described herein are the results of a pilot effort to develop engineered bamboo I-joists for use in common low-rise construction applications. Solid section bamboo materials were used to fabricate I-beams; flanges consisted of single-strand bamboo material and webs consisted of bamboo OSB or three-ply material. Experimental results indicate that flexural strengths were limited to 5.2 ksi (36 MPa) by the failure of the flange finger joints; shear strengths were 2.1 ksi (14 MPa) for the bamboo OSB and 3.3 ksi (22 MPa) for the three-ply web material. The modulus of elasticity averaged 2,000 ksi (14 GPa), while the shear modulus was 250 ksi (1.7 GPa) for the bamboo OSB and 140 ksi (0.94 GPa) for the three-ply material. Design values are developed from the test results following a hybrid approach based on ASTM procedures for wood I-joists and whole bamboo poles. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i12/p1619_s1?isAuthorized=no [article] Engineered bamboo I-joists [texte imprimé] / Mark Aschheim, Auteur ; Luisa María Gil-Martín, Auteur ; Enrique Hernandez-Montes, Auteur . - 2011 . - pp. 1619-1624. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 12 (Décembre 2010) . - pp. 1619-1624 Mots-clés : Bamboo  I-joists  Flexural  strength  Shear  strength  Stiffness  Design  values  Sustainable  materials  Rapidly  renewable  materials Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Many bamboo species are well regarded for their strength and rapid renewability, although the nonuniformity of bamboo poles has impeded use in developed countries. Described herein are the results of a pilot effort to develop engineered bamboo I-joists for use in common low-rise construction applications. Solid section bamboo materials were used to fabricate I-beams; flanges consisted of single-strand bamboo material and webs consisted of bamboo OSB or three-ply material. Experimental results indicate that flexural strengths were limited to 5.2 ksi (36 MPa) by the failure of the flange finger joints; shear strengths were 2.1 ksi (14 MPa) for the bamboo OSB and 3.3 ksi (22 MPa) for the three-ply web material. The modulus of elasticity averaged 2,000 ksi (14 GPa), while the shear modulus was 250 ksi (1.7 GPa) for the bamboo OSB and 140 ksi (0.94 GPa) for the three-ply material. Design values are developed from the test results following a hybrid approach based on ASTM procedures for wood I-joists and whole bamboo poles. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i12/p1619_s1?isAuthorized=no

Load-history effects on deformation capacity of flexural members limited by bar buckling / Despina V. Syntzirma 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. 1-11 Titre : Load-history effects on deformation capacity of flexural members limited by bar buckling Type de document : texte imprimé Auteurs : Despina V. Syntzirma, Auteur ; Stavroula J. Pantazopoulou, Auteur ; Mark Aschheim, Auteur Année de publication : 2011 Article en page(s) : pp. 1-11 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bar  buckling  Rotation  capacity  Ductility  Reinforcement  Deformation  Instability  Failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Buckling of reinforcement is one of the possible phenomena that limit the deformation capacity of reinforced concrete members under reversed cyclic loading. Previous experimental research suggests that occurrence of buckling is linked to displacement history, a parameter that is not explicitly accounted for in the available expressions for ultimate drift or curvature ductility capacities. This problem is explored in the present paper, by following through analytical expressions that relate the critical buckling strain as defined by the hysteretic stress-strain model of the reinforcement and the imposed cyclic history in terms of displacement. The analytical expressions thus derived are evaluated parametrically in order to establish behavioral trends. It is shown that when controlled by bar buckling, deformation capacity cannot be defined uniquely as it varies with the path of applied load. A primary conclusion of the research is that any quantifiable indices of deformation capacity referred to in the framework of displacement-based design using deterministic approaches need be adjusted to represent conservative lower bounds rather than approximations to the actual values of nominal failure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p1_s1?isAuthorized=no [article] Load-history effects on deformation capacity of flexural members limited by bar buckling [texte imprimé] / Despina V. Syntzirma, Auteur ; Stavroula J. Pantazopoulou, Auteur ; Mark Aschheim, Auteur . - 2011 . - pp. 1-11. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 1-11 Mots-clés : Bar  buckling  Rotation  capacity  Ductility  Reinforcement  Deformation  Instability  Failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Buckling of reinforcement is one of the possible phenomena that limit the deformation capacity of reinforced concrete members under reversed cyclic loading. Previous experimental research suggests that occurrence of buckling is linked to displacement history, a parameter that is not explicitly accounted for in the available expressions for ultimate drift or curvature ductility capacities. This problem is explored in the present paper, by following through analytical expressions that relate the critical buckling strain as defined by the hysteretic stress-strain model of the reinforcement and the imposed cyclic history in terms of displacement. The analytical expressions thus derived are evaluated parametrically in order to establish behavioral trends. It is shown that when controlled by bar buckling, deformation capacity cannot be defined uniquely as it varies with the path of applied load. A primary conclusion of the research is that any quantifiable indices of deformation capacity referred to in the framework of displacement-based design using deterministic approaches need be adjusted to represent conservative lower bounds rather than approximations to the actual values of nominal failure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i1/p1_s1?isAuthorized=no