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Glued composite timber-concrete beams. I, Interlayer connection specimen tests / Joao Henrique Jorge de Oliveira Negrao in Journal of structural engineering, Vol. 136 N° 10 (Octobre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 10 (Octobre 2010) . - pp. Titre : Glued composite timber-concrete beams. I, Interlayer connection specimen tests Type de document : texte imprimé Auteurs : Joao Henrique Jorge de Oliveira Negrao, Auteur ; Catarina Alexandra Leitao de Oliveira, Auteur ; Francisco Miguel Maia de Oliveira, Auteur Année de publication : 2011 Article en page(s) : pp. Langues : Anglais (eng) Mots-clés : Wood  structures  Composite  beams  Concrete  Bonding  Adhesives  Reinforcement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The composite interaction in timber-concrete beams is usually achieved with mechanical devices, such as shear connectors or plates driven into the materials. However, this connecting system shows some inherent inconveniences, such as the need for drillings and the limited mechanical improvement owing to interface slip. Using adhesives instead of mechanical connectors might attenuate these drawbacks. However, engineers are hesitant to apply adhesives for structural purposes, mostly because of the different thermohygrometric behavior of the adhesive and the connected material(s). This is particularly concerning timber because its hysteretic response to moisture may cause interface delamination. Therefore, as a preliminary stage for the test of composite beams, an extensive experimental campaign on small-size specimens was performed. The study focused on the shear strength at the interface and the role of some factors. Several series were considered by changing those parameters, and the results were compared. Both prefabricated and cast-on-site concrete specimens were considered. The results show that this system looks suitable for structural application, at least under steady dry conditions. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i10/p1236_s1?isAuthorized=no [article] Glued composite timber-concrete beams. I, Interlayer connection specimen tests [texte imprimé] / Joao Henrique Jorge de Oliveira Negrao, Auteur ; Catarina Alexandra Leitao de Oliveira, Auteur ; Francisco Miguel Maia de Oliveira, Auteur . - 2011 . - pp. Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 10 (Octobre 2010) . - pp. Mots-clés : Wood  structures  Composite  beams  Concrete  Bonding  Adhesives  Reinforcement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The composite interaction in timber-concrete beams is usually achieved with mechanical devices, such as shear connectors or plates driven into the materials. However, this connecting system shows some inherent inconveniences, such as the need for drillings and the limited mechanical improvement owing to interface slip. Using adhesives instead of mechanical connectors might attenuate these drawbacks. However, engineers are hesitant to apply adhesives for structural purposes, mostly because of the different thermohygrometric behavior of the adhesive and the connected material(s). This is particularly concerning timber because its hysteretic response to moisture may cause interface delamination. Therefore, as a preliminary stage for the test of composite beams, an extensive experimental campaign on small-size specimens was performed. The study focused on the shear strength at the interface and the role of some factors. Several series were considered by changing those parameters, and the results were compared. Both prefabricated and cast-on-site concrete specimens were considered. The results show that this system looks suitable for structural application, at least under steady dry conditions. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i10/p1236_s1?isAuthorized=no

Glued composite timber-concrete beams.II, Analysis and tests of beam specimens / Joao Henrique Jorge de Oliveira Negrao in Journal of structural engineering, Vol. 136 N° 10 (Octobre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 10 (Octobre 2010) . - pp. 1246-1254 Titre : Glued composite timber-concrete beams.II, Analysis and tests of beam specimens Type de document : texte imprimé Auteurs : Joao Henrique Jorge de Oliveira Negrao, Auteur ; Francisco Miguel Maia de Oliveira, Auteur ; Catarina Alexandra Leitao de Oliveira, Auteur Année de publication : 2011 Article en page(s) : pp. 1246-1254 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Wood  structures  Composite  beams  Concrete  Bonding  Adhesives  Reinforcement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper reports an experimental program on composite timber-concrete beams with glued interface. The test results are compared to those provided by an analytical model based on the assumption of a fully composite behavior. Both cast-on-site and prefabricated composite timber-concrete beams were produced, aimed at simulating rehabilitation situations or the possibility of a partial or of a full prefabrication of the composite element. Timber-concrete beams with dowel-type shear connectors were also produced and tested for comparison. The results show that the strength is similar, but the glued beams displayed a larger stiffness and, consequently, smaller deflections, which may be of relevance in design. The results also show that, at least under stabilized and dry room conditions, the prevailing mode of failure is tension in timber and, when shear failure occurs, it is mostly conditioned by the shear strength of the concrete or the timber, not by that of the adhesive. As the system depends on the shear strength of the interface, a preceding program consisting in tests on small-size composite specimens was undertaken and is reported in a companion paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i10/p1246_s1?isAuthorized=no [article] Glued composite timber-concrete beams.II, Analysis and tests of beam specimens [texte imprimé] / Joao Henrique Jorge de Oliveira Negrao, Auteur ; Francisco Miguel Maia de Oliveira, Auteur ; Catarina Alexandra Leitao de Oliveira, Auteur . - 2011 . - pp. 1246-1254. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 10 (Octobre 2010) . - pp. 1246-1254 Mots-clés : Wood  structures  Composite  beams  Concrete  Bonding  Adhesives  Reinforcement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper reports an experimental program on composite timber-concrete beams with glued interface. The test results are compared to those provided by an analytical model based on the assumption of a fully composite behavior. Both cast-on-site and prefabricated composite timber-concrete beams were produced, aimed at simulating rehabilitation situations or the possibility of a partial or of a full prefabrication of the composite element. Timber-concrete beams with dowel-type shear connectors were also produced and tested for comparison. The results show that the strength is similar, but the glued beams displayed a larger stiffness and, consequently, smaller deflections, which may be of relevance in design. The results also show that, at least under stabilized and dry room conditions, the prevailing mode of failure is tension in timber and, when shear failure occurs, it is mostly conditioned by the shear strength of the concrete or the timber, not by that of the adhesive. As the system depends on the shear strength of the interface, a preceding program consisting in tests on small-size composite specimens was undertaken and is reported in a companion paper. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i10/p1246_s1?isAuthorized=no