Direct tension pullout bond test / S. P. Tastani in Journal of structural engineering, Vol. 136 N° 6 (Juin 2010)  

Public ISBD [article]  inJournal of structural engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 731-743 Titre : Direct tension pullout bond test : experimental results Type de document : texte imprimé Auteurs : S. P. Tastani, Auteur ; S. J. Pantazopoulou, Auteur Année de publication : 2011 Article en page(s) : pp. 731-743 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Local bond Bar diameter Rib height Direct tension Pull out Anchorage length Splitting failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Results from 50 bond tests conducted using the so-called direct tension pullout specimen type are presented. Anchorages of steel bars with machined deformations were tested so as to enable a targeted study of the effect of rib height and related rib area on bond behavior; tests were conducted with or without the combined presence of external confinement over the embedded length. The novel specimen form presented in the paper was designed to simulate the state of stress arising in usual bar anchorages in the tension zones of flexural members (where both cover concrete and bar are stressed in tension). This development was motivated by the need to eliminate spurious influences of the test setup on specimen behavior, which are known to interfere with bond mechanics in conventional bond tests leading to unconservative estimates of bond strength and misleading interpretations as to the true parametric dependencies of the bond problem. Additional parameters studied in the experimental program were the development length, the cover thickness, the effect of confinement, and the tensile strength of concrete. Data reduction (local bond strength and slip estimates) was possible by fitting the exact solution of the differential equations describing the state of stress along the anchorage to the test measurements, while accounting for important phenomena such as yield penetration or debonding, and bond plastification. Next, the obtained values for local bond strength were used for calibration of the frictional analog for bond strength (a Mohr-Coulomb failure criterion). Milestone values for bond and slip were estimated with reference to the code limit-state model for bond. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i6/p731_s1?isAuthorized=no [article] Direct tension pullout bond test : experimental results [texte imprimé] / S. P. Tastani, Auteur ; S. J. Pantazopoulou, Auteur . - 2011 . - pp. 731-743. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 731-743 Mots-clés : Local bond Bar diameter Rib height Direct tension Pull out Anchorage length Splitting failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Results from 50 bond tests conducted using the so-called direct tension pullout specimen type are presented. Anchorages of steel bars with machined deformations were tested so as to enable a targeted study of the effect of rib height and related rib area on bond behavior; tests were conducted with or without the combined presence of external confinement over the embedded length. The novel specimen form presented in the paper was designed to simulate the state of stress arising in usual bar anchorages in the tension zones of flexural members (where both cover concrete and bar are stressed in tension). This development was motivated by the need to eliminate spurious influences of the test setup on specimen behavior, which are known to interfere with bond mechanics in conventional bond tests leading to unconservative estimates of bond strength and misleading interpretations as to the true parametric dependencies of the bond problem. Additional parameters studied in the experimental program were the development length, the cover thickness, the effect of confinement, and the tensile strength of concrete. Data reduction (local bond strength and slip estimates) was possible by fitting the exact solution of the differential equations describing the state of stress along the anchorage to the test measurements, while accounting for important phenomena such as yield penetration or debonding, and bond plastification. Next, the obtained values for local bond strength were used for calibration of the frictional analog for bond strength (a Mohr-Coulomb failure criterion). Milestone values for bond and slip were estimated with reference to the code limit-state model for bond. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i6/p731_s1?isAuthorized=no

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Global interventions for seismic upgrading of substandard RC buildings / G. E. Thermou in Journal of structural engineering, Vol. 138 N° 3 (Mars 2012)  

Public ISBD [article]  inJournal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 387-401 Titre : Global interventions for seismic upgrading of substandard RC buildings Type de document : texte imprimé Auteurs : G. E. Thermou, Auteur ; S. J. Pantazopoulou, Auteur ; Amr S. Elnashai, Auteur Année de publication : 2012 Article en page(s) : pp. 387-401 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Buildings Rehabilitation Reinforced concrete Seismic design Columns Walls Résumé : A methodology is developed in this paper for the design and proportioning of interventions for seismic upgrading of substandard reinforced-concrete (RC) buildings. The retrofit approach is presented in the form of a simple design tool that aims toward both demand reduction and enhancement of force and deformation supply through controlled modification of stiffness along the height of the building. This objective is achieved by engineering the translational mode-shape of the structure, so as to optimize the distribution of interstory drift. Results from the proposed approach are summarized in a spectrum format in which demand, expressed in terms of interstory drift, is related to stiffness. Design charts, which relate the characteristics of commonly used global intervention procedures to influence drift demands, are developed to facilitate the retrofit design. The intervention procedures considered in this paper are reinforced-concrete jacketing, the addition of reinforced-concrete walls, and the addition of masonry infills. The proposed methodology is also amenable to adaptation to other strengthening methods, such as the addition of cross-bracing. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p387_s1?isAuthorized=no [article] Global interventions for seismic upgrading of substandard RC buildings [texte imprimé] / G. E. Thermou, Auteur ; S. J. Pantazopoulou, Auteur ; Amr S. Elnashai, Auteur . - 2012 . - pp. 387-401. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 387-401 Mots-clés : Buildings Rehabilitation Reinforced concrete Seismic design Columns Walls Résumé : A methodology is developed in this paper for the design and proportioning of interventions for seismic upgrading of substandard reinforced-concrete (RC) buildings. The retrofit approach is presented in the form of a simple design tool that aims toward both demand reduction and enhancement of force and deformation supply through controlled modification of stiffness along the height of the building. This objective is achieved by engineering the translational mode-shape of the structure, so as to optimize the distribution of interstory drift. Results from the proposed approach are summarized in a spectrum format in which demand, expressed in terms of interstory drift, is related to stiffness. Design charts, which relate the characteristics of commonly used global intervention procedures to influence drift demands, are developed to facilitate the retrofit design. The intervention procedures considered in this paper are reinforced-concrete jacketing, the addition of reinforced-concrete walls, and the addition of masonry infills. The proposed methodology is also amenable to adaptation to other strengthening methods, such as the addition of cross-bracing. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p387_s1?isAuthorized=no

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