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Cyclic seismic testing of composite concrete-filled U-shaped steel beam to H-shaped column connections / Cheol-Ho Lee in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 360–378 Titre : Cyclic seismic testing of composite concrete-filled U-shaped steel beam to H-shaped column connections Type de document : texte imprimé Auteurs : Cheol-Ho Lee, Auteur ; Hong-Gun Park, Auteur ; Chang-Hee Park, Auteur Année de publication : 2013 Article en page(s) : pp. 360–378 Note générale : structural engineering Langues : Anglais (eng) Mots-clés : seismic  composite  connection;  U-shaped  composite  beam;  cyclic  tests;  special  moment  frames Résumé : In this study, the cyclic seismic performance of a concrete-filled U-shaped steel beam to H-shaped steel column connections was experimentally evaluated. The concrete-filled U-shaped steel beams were compositely attached to the concrete floor slab. The test was conducted in two stages. The first testing program was carried out on one-sided moment connections to find the most promising connecting scheme. The strengthening scheme, or welding steel plates to the beam bottom flange with minimized stress concentration, was shown to be the most satisfactory, and it was used in the second-stage test on two full-scale cruciform specimens. Considering the unique constructional nature of the proposed composite connections, the critical limit states such as weld fracture, local buckling, concrete crushing, and rebar buckling were carefully addressed in designing specimens. Test results showed that the connection details and design procedures proposed in this study can successfully control the critical limit states mentioned previously. The proposed connection detail successfully pushed the plastic hinging to the tip of the strengthened zone as intended in design, thus effectively protecting the more vulnerable beam-to-column welded joint. The specimens typically exhibited a maximum story drift capacity of more than 5.5% rad, exceeding the minimum limit of 4% rad required of special moment frames. Four of the five specimens tested in this study eventually failed because of a low-cycle fatigue fracture across the beam bottom flange at a high story drift greater than 5.0% rad. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000635 [article] Cyclic seismic testing of composite concrete-filled U-shaped steel beam to H-shaped column connections [texte imprimé] / Cheol-Ho Lee, Auteur ; Hong-Gun Park, Auteur ; Chang-Hee Park, Auteur . - 2013 . - pp. 360–378. structural engineering Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 360–378 Mots-clés : seismic  composite  connection;  U-shaped  composite  beam;  cyclic  tests;  special  moment  frames Résumé : In this study, the cyclic seismic performance of a concrete-filled U-shaped steel beam to H-shaped steel column connections was experimentally evaluated. The concrete-filled U-shaped steel beams were compositely attached to the concrete floor slab. The test was conducted in two stages. The first testing program was carried out on one-sided moment connections to find the most promising connecting scheme. The strengthening scheme, or welding steel plates to the beam bottom flange with minimized stress concentration, was shown to be the most satisfactory, and it was used in the second-stage test on two full-scale cruciform specimens. Considering the unique constructional nature of the proposed composite connections, the critical limit states such as weld fracture, local buckling, concrete crushing, and rebar buckling were carefully addressed in designing specimens. Test results showed that the connection details and design procedures proposed in this study can successfully control the critical limit states mentioned previously. The proposed connection detail successfully pushed the plastic hinging to the tip of the strengthened zone as intended in design, thus effectively protecting the more vulnerable beam-to-column welded joint. The specimens typically exhibited a maximum story drift capacity of more than 5.5% rad, exceeding the minimum limit of 4% rad required of special moment frames. Four of the five specimens tested in this study eventually failed because of a low-cycle fatigue fracture across the beam bottom flange at a high story drift greater than 5.0% rad. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000635

Parallel axial-flexural hinge model for nonlinear dynamic progressive collapse analysis of welded steel moment frames / Cheol-Ho Lee in Journal of structural engineering, Vol. 136 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 2 (Fevrier 2010) . - pp. 165-173 Titre : Parallel axial-flexural hinge model for nonlinear dynamic progressive collapse analysis of welded steel moment frames Type de document : texte imprimé Auteurs : Cheol-Ho Lee, Auteur ; Seonwoong Kim, Auteur ; Kyungkoo Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 165-173 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Progressive  collapse  Steel  moment  frames  Plastic  hinge  Moment-axial  tension  interaction  Nonlinear  dynamic  analysis Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this study, a parallel axial-flexural hinge model capable of representing postyield flexural behavior and considering interaction effects of axial force and moment is proposed for a simplified nonlinear progressive collapse analysis of welded steel moment frames. To this end, the load-resisting mechanism of the column-removed double-span beams was investigated based on the material and geometric nonlinear parametric finite-element analysis. A multilinear parallel point hinge model which captures the moment-axial tension interaction was then proposed. The emphasis was to develop a reliable and computationally efficient macromodel for practical progressive collapse analysis. The application of the proposed hinge model to nonlinear dynamic progressive collapse analysis was illustrated by using OpenSEES program. The accuracy as well as the efficiency of the proposed model was verified based on inelastic dynamic finite-element analysis results. The importance of including catenary action effects for proper progressive collapse resistant analysis and design was also emphasized. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i2/p165_s1?isAuthorized=no [article] Parallel axial-flexural hinge model for nonlinear dynamic progressive collapse analysis of welded steel moment frames [texte imprimé] / Cheol-Ho Lee, Auteur ; Seonwoong Kim, Auteur ; Kyungkoo Lee, Auteur . - 2011 . - pp. 165-173. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 2 (Fevrier 2010) . - pp. 165-173 Mots-clés : Progressive  collapse  Steel  moment  frames  Plastic  hinge  Moment-axial  tension  interaction  Nonlinear  dynamic  analysis Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this study, a parallel axial-flexural hinge model capable of representing postyield flexural behavior and considering interaction effects of axial force and moment is proposed for a simplified nonlinear progressive collapse analysis of welded steel moment frames. To this end, the load-resisting mechanism of the column-removed double-span beams was investigated based on the material and geometric nonlinear parametric finite-element analysis. A multilinear parallel point hinge model which captures the moment-axial tension interaction was then proposed. The emphasis was to develop a reliable and computationally efficient macromodel for practical progressive collapse analysis. The application of the proposed hinge model to nonlinear dynamic progressive collapse analysis was illustrated by using OpenSEES program. The accuracy as well as the efficiency of the proposed model was verified based on inelastic dynamic finite-element analysis results. The importance of including catenary action effects for proper progressive collapse resistant analysis and design was also emphasized. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i2/p165_s1?isAuthorized=no

Prediction of column axial forces in inverted v-braced seismic steel frames considering brace buckling / ChunHee Cho in Journal of structural engineering, Vol. 137 N° 12 (Décembre 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1440-1450 Titre : Prediction of column axial forces in inverted v-braced seismic steel frames considering brace buckling Type de document : texte imprimé Auteurs : ChunHee Cho, Auteur ; Cheol-Ho Lee, Auteur ; Jeong-Jae Kim, Auteur Année de publication : 2012 Article en page(s) : pp. 1440-1450 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Brace  buckling  Concentrically  braced  frame  Vertical  unbalanced  force  Column  design  Higher  mode  effects  Pushover  analysis  Seismic Résumé : Brace buckling in inverted-V-braced frames induces the vertical unbalanced force. The columns in the braced bay should be designed, per the capacity design concept, to remain elastic for gravity load actions and additional column axial forces that result from the brace buckling. However, owing to the difficulty in accumulating the buckling-induced column forces from different stories, empirical and often conservative approaches have been used in design practice. In this paper, three combination rules for a rational estimation of the column axial forces are proposed. The idea central to the three methods is to detect the stories with high buckling potential as precisely as possible by using pushover analysis and/or simple demand-to-capacity analysis. The vertical unbalanced forces in the stories detected as high buckling potential are then summed in a linear manner, whereas those otherwise are combined by following the SRSS (square root of sum of squares) rule. The accuracy and design advantage of the three methods is evaluated on the basis of extensive inelastic dynamic analyses. The mode shape-based method (MSBM), which is both simple and accurate, is recommended as the method of choice for practicing engineers among the three proposed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i12/p1440_s1?isAuthorized=no [article] Prediction of column axial forces in inverted v-braced seismic steel frames considering brace buckling [texte imprimé] / ChunHee Cho, Auteur ; Cheol-Ho Lee, Auteur ; Jeong-Jae Kim, Auteur . - 2012 . - pp. 1440-1450. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1440-1450 Mots-clés : Brace  buckling  Concentrically  braced  frame  Vertical  unbalanced  force  Column  design  Higher  mode  effects  Pushover  analysis  Seismic Résumé : Brace buckling in inverted-V-braced frames induces the vertical unbalanced force. The columns in the braced bay should be designed, per the capacity design concept, to remain elastic for gravity load actions and additional column axial forces that result from the brace buckling. However, owing to the difficulty in accumulating the buckling-induced column forces from different stories, empirical and often conservative approaches have been used in design practice. In this paper, three combination rules for a rational estimation of the column axial forces are proposed. The idea central to the three methods is to detect the stories with high buckling potential as precisely as possible by using pushover analysis and/or simple demand-to-capacity analysis. The vertical unbalanced forces in the stories detected as high buckling potential are then summed in a linear manner, whereas those otherwise are combined by following the SRSS (square root of sum of squares) rule. The accuracy and design advantage of the three methods is evaluated on the basis of extensive inelastic dynamic analyses. The mode shape-based method (MSBM), which is both simple and accurate, is recommended as the method of choice for practicing engineers among the three proposed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i12/p1440_s1?isAuthorized=no