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Analytical and numerical modeling of prestressed continuous steel-concrete composite beams / Jianguo Nie 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. 1405-1418 Titre : Analytical and numerical modeling of prestressed continuous steel-concrete composite beams Type de document : texte imprimé Auteurs : Jianguo Nie, Auteur ; Muxuan Tao, Auteur ; C. S. Cai, Auteur Année de publication : 2012 Article en page(s) : pp. 1405-1418 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Prestressed  concrete  Composite  beam  Continuous  beam  Loading  capacity  Crack  load  Yield  load  Ultimate  load  Finite  element  analysis  Nonlinear  Whole  process Résumé : A loading capacity analysis is conducted for prestressed continuous steel-concrete composite beams. On the basis of the basic theoretical framework of the solution of externally unbonded prestressed structures, formulas for calculating the three characteristic loads (crack, yield, and ultimate loads) of two-span prestressed continuous composite beams under symmetric concentrated loads are proposed and extended to general cases. The variation of tendon force is considered and the adopted limit equilibrium approach only requires the development of equilibrium equations, which avoids the solution of cumbersome simultaneous deformation compatibility equations. Furthermore, an elaborate finite element model is presented for simulating the nonlinear behavior of prestressed continuous composite beams by using the commercial finite element package. The numerical model considering both the material and geometric nonlinearities can fully reflect the complex behaviors of prestressed continuous composite beams during the whole loading process. The comparisons among the analytical, numerical, and experimental results demonstrate that the analytical method provides a convenient and reliable tool for a routine design practice and the finite element model provides an excellent numerical simulation for the nonlinear behavior of prestressed continuous composite beams. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i12/p1405_s1?isAuthorized=no [article] Analytical and numerical modeling of prestressed continuous steel-concrete composite beams [texte imprimé] / Jianguo Nie, Auteur ; Muxuan Tao, Auteur ; C. S. Cai, Auteur . - 2012 . - pp. 1405-1418. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 12 (Décembre 2011) . - pp. 1405-1418 Mots-clés : Prestressed  concrete  Composite  beam  Continuous  beam  Loading  capacity  Crack  load  Yield  load  Ultimate  load  Finite  element  analysis  Nonlinear  Whole  process Résumé : A loading capacity analysis is conducted for prestressed continuous steel-concrete composite beams. On the basis of the basic theoretical framework of the solution of externally unbonded prestressed structures, formulas for calculating the three characteristic loads (crack, yield, and ultimate loads) of two-span prestressed continuous composite beams under symmetric concentrated loads are proposed and extended to general cases. The variation of tendon force is considered and the adopted limit equilibrium approach only requires the development of equilibrium equations, which avoids the solution of cumbersome simultaneous deformation compatibility equations. Furthermore, an elaborate finite element model is presented for simulating the nonlinear behavior of prestressed continuous composite beams by using the commercial finite element package. The numerical model considering both the material and geometric nonlinearities can fully reflect the complex behaviors of prestressed continuous composite beams during the whole loading process. The comparisons among the analytical, numerical, and experimental results demonstrate that the analytical method provides a convenient and reliable tool for a routine design practice and the finite element model provides an excellent numerical simulation for the nonlinear behavior of prestressed continuous composite beams. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i12/p1405_s1?isAuthorized=no

Comparative study on steel plate shear walls used in a high-rise building / Jianguo Nie in Journal of structural engineering, Vol. 139 N° 1 (Janvier 2013) 

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 85–97 Titre : Comparative study on steel plate shear walls used in a high-rise building Type de document : texte imprimé Auteurs : Jianguo Nie, Auteur ; Jiansheng Fan, Auteur ; Xiaogang Liu, Auteur Année de publication : 2013 Article en page(s) : pp. 85–97 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Steel  plate  shear  wall  Concrete-filled  tubular  columns  Low-cycle  reverse  loading  Stiffener Résumé : Tianjin Jinta Tower is the first high-rise building built with steel plate shear walls in China. The main lateral force resisting system is the composite core tube composed of steel plate shear walls and concrete-filled steel tubular columns. To investigate the seismic performance of this structural system and to provide design instructions, two specimens of 2-bay and 5-story steel plate shear walls were tested under low-cycle reverse loading. The unstiffened steel plates of the first specimen were connected to the boundary beam and column frame by high-strength bolts. The steel plates of the second specimen were connected to the boundary frame by welding, and the steel panels were stiffened by channels. Both specimens showed satisfactory energy dissipation mechanisms during the loading process. For the unstiffened specimen with bolted connections, the considerable postbuckling strength generated excellent ductility and energy dissipation performance, but a slip at the bolted connections and the buckling of steel panels decreased the stiffness in the serviceability condition. The stiffened and welded specimen showed higher stiffness in the elastic range and excellent energy dissipation capacity, but the cost of stiffeners would decrease the economy of the steel plate shear walls. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000613 [article] Comparative study on steel plate shear walls used in a high-rise building [texte imprimé] / Jianguo Nie, Auteur ; Jiansheng Fan, Auteur ; Xiaogang Liu, Auteur . - 2013 . - pp. 85–97. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 85–97 Mots-clés : Steel  plate  shear  wall  Concrete-filled  tubular  columns  Low-cycle  reverse  loading  Stiffener Résumé : Tianjin Jinta Tower is the first high-rise building built with steel plate shear walls in China. The main lateral force resisting system is the composite core tube composed of steel plate shear walls and concrete-filled steel tubular columns. To investigate the seismic performance of this structural system and to provide design instructions, two specimens of 2-bay and 5-story steel plate shear walls were tested under low-cycle reverse loading. The unstiffened steel plates of the first specimen were connected to the boundary beam and column frame by high-strength bolts. The steel plates of the second specimen were connected to the boundary frame by welding, and the steel panels were stiffened by channels. Both specimens showed satisfactory energy dissipation mechanisms during the loading process. For the unstiffened specimen with bolted connections, the considerable postbuckling strength generated excellent ductility and energy dissipation performance, but a slip at the bolted connections and the buckling of steel panels decreased the stiffness in the serviceability condition. The stiffened and welded specimen showed higher stiffness in the elastic range and excellent energy dissipation capacity, but the cost of stiffeners would decrease the economy of the steel plate shear walls. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000613

Experimental research on fatigue behavior of RC beams strengthened with steel plate-concrete composite technique / Jianguo Nie in Journal of structural engineering, Vol. 137 N° 7 (Juillet 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 7 (Juillet 2011) . - pp. 772-781 Titre : Experimental research on fatigue behavior of RC beams strengthened with steel plate-concrete composite technique Type de document : texte imprimé Auteurs : Jianguo Nie, Auteur ; Yuhang Wang, Auteur ; C. S. Cai, Auteur Année de publication : 2011 Article en page(s) : pp. 772-781 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Steel  plate-concrete  composite  technique  Strengthening  Strengthening  under  sustained  load  Load  bearing  capacity  Fatigue Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Based on fatigue experiments on eight reinforced concrete (RC) beams strengthened with the steel plate-concrete composite (SPCC) technique, the fatigue life and development trend of stiffness and strain of specimens under a constant amplitude fatigue loading were studied. The experimental results showed that the fatigue failure mode of the SPCC strengthened beams was the fatigue failure of the steel plate. The initial fatigue crack in the steel plate appeared near the weld toe of studs and then expanded through the plate. Unlike regular RC beams, the fatigue failure mode of the tested specimens was ductile. The amplitude of stress in the steel plate had the most important influence on the fatigue behavior of RC beams strengthened with the SPCC technique. The level and amplitude of stress in the steel plate should be strictly controlled in practical design, and therefore, the high-strength steel and thin steel plate were not suitable for RC beams strengthened with the SPCC technique. The prestress in the steel plate could improve the fatigue life of RC beams strengthened with the SPCC technique. The S-N curve of the tension steel plate, welded with studs specified in the British code of practice for bridge design, BS5400, was conservative for the design of steel plate in RC beams strengthened with the SPCC technique. Calculation models were presented of the residual static capacity and stiffness of RC beams strengthened with the SPCC technique after fatigue failure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i7/p772_s1?isAuthorized=no [article] Experimental research on fatigue behavior of RC beams strengthened with steel plate-concrete composite technique [texte imprimé] / Jianguo Nie, Auteur ; Yuhang Wang, Auteur ; C. S. Cai, Auteur . - 2011 . - pp. 772-781. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 7 (Juillet 2011) . - pp. 772-781 Mots-clés : Steel  plate-concrete  composite  technique  Strengthening  Strengthening  under  sustained  load  Load  bearing  capacity  Fatigue Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Based on fatigue experiments on eight reinforced concrete (RC) beams strengthened with the steel plate-concrete composite (SPCC) technique, the fatigue life and development trend of stiffness and strain of specimens under a constant amplitude fatigue loading were studied. The experimental results showed that the fatigue failure mode of the SPCC strengthened beams was the fatigue failure of the steel plate. The initial fatigue crack in the steel plate appeared near the weld toe of studs and then expanded through the plate. Unlike regular RC beams, the fatigue failure mode of the tested specimens was ductile. The amplitude of stress in the steel plate had the most important influence on the fatigue behavior of RC beams strengthened with the SPCC technique. The level and amplitude of stress in the steel plate should be strictly controlled in practical design, and therefore, the high-strength steel and thin steel plate were not suitable for RC beams strengthened with the SPCC technique. The prestress in the steel plate could improve the fatigue life of RC beams strengthened with the SPCC technique. The S-N curve of the tension steel plate, welded with studs specified in the British code of practice for bridge design, BS5400, was conservative for the design of steel plate in RC beams strengthened with the SPCC technique. Calculation models were presented of the residual static capacity and stiffness of RC beams strengthened with the SPCC technique after fatigue failure. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i7/p772_s1?isAuthorized=no

Long-term behavior of composite beams under positive and negative bending. I, Experimental study / Jiansheng Fan in Journal of structural engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 849-857 Titre : Long-term behavior of composite beams under positive and negative bending. I, Experimental study Type de document : texte imprimé Auteurs : Jiansheng Fan, Auteur ; Jianguo Nie, Auteur ; Quanwang Li, Auteur Année de publication : 2011 Article en page(s) : pp. 849-857 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Shrinkage  Creep  Crack  Composite  steel-concrete  beam  Long-term  test Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents an experimental program designed to examine the long-term behavior of composite steel-concrete beams under sustained loads. The test program consisted of two simply supported beams under positive bending moments and two cantilever beams under negative bending moments. Long-term deflections, strains, and the cracking behaviors of the specimen beams were monitored over a period of 3 years. The primary observations are: (1) the deflection of the simply supported beam under positive bending moment increased quite significantly over the time due to creep and shrinkage, with the midspan deflections after 3 years of loading reached 2.5 times of the initial deflections, and (2) the cracking of concrete occurred in hogging moment regions for cantilever beams due to the combined effects of concrete shrinkage and sustained negative bending moments. Current design codes were evaluated through a comparison between the calculations and testing results. It was found that the effective modulus method provides a satisfactory prediction on deflections and strains for beams under positive bending moments. But for beams under negative bending moment, the stiffness reduction due to cracking effect should be considered in calculation. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i7/p849_s1?isAuthorized=no [article] Long-term behavior of composite beams under positive and negative bending. I, Experimental study [texte imprimé] / Jiansheng Fan, Auteur ; Jianguo Nie, Auteur ; Quanwang Li, Auteur . - 2011 . - pp. 849-857. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 849-857 Mots-clés : Shrinkage  Creep  Crack  Composite  steel-concrete  beam  Long-term  test Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents an experimental program designed to examine the long-term behavior of composite steel-concrete beams under sustained loads. The test program consisted of two simply supported beams under positive bending moments and two cantilever beams under negative bending moments. Long-term deflections, strains, and the cracking behaviors of the specimen beams were monitored over a period of 3 years. The primary observations are: (1) the deflection of the simply supported beam under positive bending moment increased quite significantly over the time due to creep and shrinkage, with the midspan deflections after 3 years of loading reached 2.5 times of the initial deflections, and (2) the cracking of concrete occurred in hogging moment regions for cantilever beams due to the combined effects of concrete shrinkage and sustained negative bending moments. Current design codes were evaluated through a comparison between the calculations and testing results. It was found that the effective modulus method provides a satisfactory prediction on deflections and strains for beams under positive bending moments. But for beams under negative bending moment, the stiffness reduction due to cracking effect should be considered in calculation. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i7/p849_s1?isAuthorized=no