Documents disponibles écrits par cet auteur

Probabilistic capacity models for corroding posttensioning strands calibrated using laboratory results / Gardoni, Paolo in Journal of engineering mechanics, Vol. 135 N° 9 (Septembre 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 9 (Septembre 2009) . - pp. 906-916 Titre : Probabilistic capacity models for corroding posttensioning strands calibrated using laboratory results Type de document : texte imprimé Auteurs : Gardoni, Paolo, Auteur ; Pillai, Radhakrishna G., Auteur ; Hueste, Mary Beth D., Auteur Article en page(s) : pp. 906-916 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Chlorides  Corrosion  Tension  Voids  Ducts  Bridges  Florida  Probability  Capacity. Résumé : The presence of air voids, moisture, and chlorides inside tendons or ducts was cited as a reason for the early age strand corrosion and failure in the Mid-bay, Sunshine Skyway, and Niles Channel posttensioned (PT) bridges in Florida, United States. Although rare, these incidents call for frequent inspection and structural reliability assessment of PT bridges exposed to moisture and chlorides. This paper develops and presents probabilistic strand capacity models that are needed to assess the structural reliability of such PT bridges and recommends a time frequency of inspection. A total of 384 strand test specimens were exposed to various void, moisture, and chloride concentration conditions for 12 and 21 months; the remaining tension capacities were then determined. Using this experimental data and a Bayesian approach, six probabilistic capacity models were developed based on the void type. The mean absolute percentage errors of these models are less than 4%, indicating that reasonably accurate prediction of the strand capacity is possible, when void, aggressive moisture, and chloride conditions are present. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...] [article] Probabilistic capacity models for corroding posttensioning strands calibrated using laboratory results [texte imprimé] / Gardoni, Paolo, Auteur ; Pillai, Radhakrishna G., Auteur ; Hueste, Mary Beth D., Auteur . - pp. 906-916. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 9 (Septembre 2009) . - pp. 906-916 Mots-clés : Chlorides  Corrosion  Tension  Voids  Ducts  Bridges  Florida  Probability  Capacity. Résumé : The presence of air voids, moisture, and chlorides inside tendons or ducts was cited as a reason for the early age strand corrosion and failure in the Mid-bay, Sunshine Skyway, and Niles Channel posttensioned (PT) bridges in Florida, United States. Although rare, these incidents call for frequent inspection and structural reliability assessment of PT bridges exposed to moisture and chlorides. This paper develops and presents probabilistic strand capacity models that are needed to assess the structural reliability of such PT bridges and recommends a time frequency of inspection. A total of 384 strand test specimens were exposed to various void, moisture, and chloride concentration conditions for 12 and 21 months; the remaining tension capacities were then determined. Using this experimental data and a Bayesian approach, six probabilistic capacity models were developed based on the void type. The mean absolute percentage errors of these models are less than 4%, indicating that reasonably accurate prediction of the strand capacity is possible, when void, aggressive moisture, and chloride conditions are present. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...]

Shear characteristics and design for high-strength self-consolidating concrete / Young Hoon Kim in Journal of structural engineering, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 989-1000 Titre : Shear characteristics and design for high-strength self-consolidating concrete Type de document : texte imprimé Auteurs : Young Hoon Kim, Auteur ; Hueste, Mary Beth D., Auteur ; David Trejo, Auteur Année de publication : 2011 Article en page(s) : pp. 989-1000 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Self-consolidating  concrete  Shear  design  Aggregate  interlock  AASHTO  LRFD  design  specifications  Modified  compression  field  theory  Precast  Prestressed  members Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : To achieve adequate flow and homogeneous concrete for precast, prestressed members, self-consolidating concrete (SCC) typically has higher paste and lower coarse aggregate volumes than conventional concrete (CC). The lower aggregate content of SCC can affect the shear capacity of concrete systems. This research performed 48 push-off tests to investigate the influence of SCC aggregate and paste volumes on the shear capacity and these results were compared with those obtained from similar CC samples. The variables included coarse aggregate type (river gravel and limestone), three coarse aggregate volumes for the SCC mixtures, and two target 16-h release strengths [34 and 48 MPa (5 and 7 ksi)]. The aggregate type, aggregate volume, and concrete strength were found to have significant effects on the aggregate interlock. Test results were used to propose new aggregate interlock models based on the modified compression field theory adopted in the AASHTO Load and Resistance Factor Design Specifications. More appropriate expressions have been developed to determine the limiting value of concrete shear strength for CC and SCC precast, prestressed concrete girders with similar mixture proportions, and a 28-day compressive strength greater than 70 MPa (10 ksi). DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p989_s1?isAuthorized=no [article] Shear characteristics and design for high-strength self-consolidating concrete [texte imprimé] / Young Hoon Kim, Auteur ; Hueste, Mary Beth D., Auteur ; David Trejo, Auteur . - 2011 . - pp. 989-1000. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 989-1000 Mots-clés : Self-consolidating  concrete  Shear  design  Aggregate  interlock  AASHTO  LRFD  design  specifications  Modified  compression  field  theory  Precast  Prestressed  members Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : To achieve adequate flow and homogeneous concrete for precast, prestressed members, self-consolidating concrete (SCC) typically has higher paste and lower coarse aggregate volumes than conventional concrete (CC). The lower aggregate content of SCC can affect the shear capacity of concrete systems. This research performed 48 push-off tests to investigate the influence of SCC aggregate and paste volumes on the shear capacity and these results were compared with those obtained from similar CC samples. The variables included coarse aggregate type (river gravel and limestone), three coarse aggregate volumes for the SCC mixtures, and two target 16-h release strengths [34 and 48 MPa (5 and 7 ksi)]. The aggregate type, aggregate volume, and concrete strength were found to have significant effects on the aggregate interlock. Test results were used to propose new aggregate interlock models based on the modified compression field theory adopted in the AASHTO Load and Resistance Factor Design Specifications. More appropriate expressions have been developed to determine the limiting value of concrete shear strength for CC and SCC precast, prestressed concrete girders with similar mixture proportions, and a 28-day compressive strength greater than 70 MPa (10 ksi). DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p989_s1?isAuthorized=no