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Collapse assessment of steel moment frames based on E-defense full-scale shake table collapse tests / Dimitrios G. Lignos 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. 120–132 Titre : Collapse assessment of steel moment frames based on E-defense full-scale shake table collapse tests Type de document : texte imprimé Auteurs : Dimitrios G. Lignos, Auteur ; Tsuyoshi Hikino, Auteur ; Yuichi Matsuoka, Auteur Année de publication : 2013 Article en page(s) : pp. 120–132 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Collapse  Component  deterioration  Full-scale  collapse  tests  Steel  structures  Local  buckling  Strong-column/weak-beam  ratio  Exposed  column  bases  Collapse  simulation  Sidesway  collapse Résumé : This paper presents key parameters that affect numerical modeling of steel frame structures for reliable collapse simulations. The collapse assessment is based on experimental data obtained from a full-scale shaking table collapse test of a 4-story steel moment frame and a blind numerical analysis contest that was organized in parallel with the collapse test. It is shown that (1) there is no clear advantage between three-dimensional (3D) and 2D analyses in the prediction of a sidesway collapse mechanism for buildings with a regular plan view as in the case of study; (2) the assumption of Rayleigh damping leads to better predictions of structural response compared with stiffness proportional damping; and (3) accurate prediction of collapse necessitates that P-Δ effects always be considered in the analysis. It is also proven that accurate simulation of steel component deterioration is a key factor for reliable prediction of collapse behavior. On the basis of a synthesis of experimental and analytical studies, a few collapse mitigation alternatives are investigated. In particular, the effects of the strong-column/weak-beam ratio and exposed base plates on the collapse capacity are assessed. It is notable that a combination of bending strength increase and delay of local buckling in first-story columns is most effective for the enhancement of seismic performance against collapse. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000608 [article] Collapse assessment of steel moment frames based on E-defense full-scale shake table collapse tests [texte imprimé] / Dimitrios G. Lignos, Auteur ; Tsuyoshi Hikino, Auteur ; Yuichi Matsuoka, Auteur . - 2013 . - pp. 120–132. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 120–132 Mots-clés : Collapse  Component  deterioration  Full-scale  collapse  tests  Steel  structures  Local  buckling  Strong-column/weak-beam  ratio  Exposed  column  bases  Collapse  simulation  Sidesway  collapse Résumé : This paper presents key parameters that affect numerical modeling of steel frame structures for reliable collapse simulations. The collapse assessment is based on experimental data obtained from a full-scale shaking table collapse test of a 4-story steel moment frame and a blind numerical analysis contest that was organized in parallel with the collapse test. It is shown that (1) there is no clear advantage between three-dimensional (3D) and 2D analyses in the prediction of a sidesway collapse mechanism for buildings with a regular plan view as in the case of study; (2) the assumption of Rayleigh damping leads to better predictions of structural response compared with stiffness proportional damping; and (3) accurate prediction of collapse necessitates that P-Δ effects always be considered in the analysis. It is also proven that accurate simulation of steel component deterioration is a key factor for reliable prediction of collapse behavior. On the basis of a synthesis of experimental and analytical studies, a few collapse mitigation alternatives are investigated. In particular, the effects of the strong-column/weak-beam ratio and exposed base plates on the collapse capacity are assessed. It is notable that a combination of bending strength increase and delay of local buckling in first-story columns is most effective for the enhancement of seismic performance against collapse. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000608

Deterioration modeling of steel components in support of collapse prediction of steel moment frames under earthquake loading / Dimitrios G. Lignos in Journal of structural engineering, Vol. 137 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1291-1302 Titre : Deterioration modeling of steel components in support of collapse prediction of steel moment frames under earthquake loading Type de document : texte imprimé Auteurs : Dimitrios G. Lignos, Auteur ; Helmut Krawinkler, Auteur Année de publication : 2012 Article en page(s) : pp. 1291-1302 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Component  deterioration  Steel  database  Steel  moment  connections  Sidesway  collapse  Moment-rotation  relationships  Residual  strength  Deterioration  models  Reduced  beam  section Résumé : Reliable collapse assessment of structural systems under earthquake loading requires analytical models that are able to capture component deterioration in strength and stiffness. For calibration and validation of these models, a large set of experimental data is needed. This paper discusses the development of a database of experimental data of steel components and the use of this database for quantification of important parameters that affect the cyclic moment-rotation relationship at plastic hinge regions in beams. On the basis of information deduced from the steel component database, empirical relationships for modeling of precapping plastic rotation, postcapping rotation, and cyclic deterioration for beams with reduced beam section (RBS) and other-than-RBS beams are proposed. Quantitative information is also provided for modeling of the effective yield strength, postyield strength ratio, residual strength, and ductile tearing of steel components subjected to cyclic loading. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i11/p1291_s1?isAuthorized=no [article] Deterioration modeling of steel components in support of collapse prediction of steel moment frames under earthquake loading [texte imprimé] / Dimitrios G. Lignos, Auteur ; Helmut Krawinkler, Auteur . - 2012 . - pp. 1291-1302. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1291-1302 Mots-clés : Component  deterioration  Steel  database  Steel  moment  connections  Sidesway  collapse  Moment-rotation  relationships  Residual  strength  Deterioration  models  Reduced  beam  section Résumé : Reliable collapse assessment of structural systems under earthquake loading requires analytical models that are able to capture component deterioration in strength and stiffness. For calibration and validation of these models, a large set of experimental data is needed. This paper discusses the development of a database of experimental data of steel components and the use of this database for quantification of important parameters that affect the cyclic moment-rotation relationship at plastic hinge regions in beams. On the basis of information deduced from the steel component database, empirical relationships for modeling of precapping plastic rotation, postcapping rotation, and cyclic deterioration for beams with reduced beam section (RBS) and other-than-RBS beams are proposed. Quantitative information is also provided for modeling of the effective yield strength, postyield strength ratio, residual strength, and ductile tearing of steel components subjected to cyclic loading. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i11/p1291_s1?isAuthorized=no

Fragility assessment of reduced beam section moment connections / Dimitrios G. Lignos in Journal of structural engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1140-1150 Titre : Fragility assessment of reduced beam section moment connections Type de document : texte imprimé Auteurs : Dimitrios G. Lignos, Auteur ; Dimitrios Kolios, Auteur ; Miranda, Eduardo, Auteur Année de publication : 2011 Article en page(s) : pp. 1140-1150 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Reduced  beam  section  Performance  evaluation  Fragility  function  Experimental  data  Damage  assessment  Steel  structures  Beam-to-column  moment  connection Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents fragility functions to estimate the probability of reaching or exceeding different damage states in reduced beam section (RBS) beam-to-column moment connections of steel moment resisting frames. The fragility functions are developed using results from 71 experimental tests that have been conducted on RBS connections during the past 14 years. The main sources of uncertainty considered are specimen-to-specimen variability of the interstory drifts associated with the various damage states and the epistemic uncertainty arising from using a limited number of experimental data and from interpreting experimental results. Quantitative measures for each of these two kinds of uncertainty were developed using statistical procedures. For a given peak interstory drift ratio the fragility functions developed herein permit the estimation of the probability of experiencing five different levels of damage in RBS moment connections. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i9/p1140_s1?isAuthorized=no [article] Fragility assessment of reduced beam section moment connections [texte imprimé] / Dimitrios G. Lignos, Auteur ; Dimitrios Kolios, Auteur ; Miranda, Eduardo, Auteur . - 2011 . - pp. 1140-1150. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1140-1150 Mots-clés : Reduced  beam  section  Performance  evaluation  Fragility  function  Experimental  data  Damage  assessment  Steel  structures  Beam-to-column  moment  connection Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents fragility functions to estimate the probability of reaching or exceeding different damage states in reduced beam section (RBS) beam-to-column moment connections of steel moment resisting frames. The fragility functions are developed using results from 71 experimental tests that have been conducted on RBS connections during the past 14 years. The main sources of uncertainty considered are specimen-to-specimen variability of the interstory drifts associated with the various damage states and the epistemic uncertainty arising from using a limited number of experimental data and from interpreting experimental results. Quantitative measures for each of these two kinds of uncertainty were developed using statistical procedures. For a given peak interstory drift ratio the fragility functions developed herein permit the estimation of the probability of experiencing five different levels of damage in RBS moment connections. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i9/p1140_s1?isAuthorized=no

Use of wavelet-based damage-sensitive features for structural damage diagnosis using strong motion data / Hae Young Noh in Journal of structural engineering, Vol. 137 N° 10 (Octobre 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 1215-1228 Titre : Use of wavelet-based damage-sensitive features for structural damage diagnosis using strong motion data Type de document : texte imprimé Auteurs : Hae Young Noh, Auteur ; Nair, K. Krishnan, Auteur ; Dimitrios G. Lignos, Auteur Année de publication : 2012 Article en page(s) : pp. 1215-1228 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Assessment  Monitoring  Nonstationary  processes  Earthquake  engineering  Diagnosis  Structural  failures  Frequency  analysis  Natural  frequency Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper introduces three wavelet-based damage-sensitive features (DSFs) extracted from structural responses recorded during earthquakes to diagnose structural damage. Because earthquake excitations are nonstationary, the wavelet transform, which represents data as a weighted sum of time-localized waves, is used to model the structural responses. These DSFs are defined as functions of wavelet energies at particular frequencies and specific times. The first DSF (DSF1) indicates how the wavelet energy at the original natural frequency of the structure changes as the damage progresses. The second DSF (DSF2) indicates how much the wavelet energy is spread out in time. The third DSF (DSF3) reflects how slowly the wavelet energy decays with time. The performance of these DSFs is validated using two sets of shake-table test data. The results show that as the damage extent increases, the DSF1 value decreases and the DSF2 and DSF3 values increase. Thus, these DSFs can be used to diagnose structural damage. The robustness of these DSFs to different input ground motions is also investigated using a set of simulated data. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i10/p1215_s1?isAuthorized=no [article] Use of wavelet-based damage-sensitive features for structural damage diagnosis using strong motion data [texte imprimé] / Hae Young Noh, Auteur ; Nair, K. Krishnan, Auteur ; Dimitrios G. Lignos, Auteur . - 2012 . - pp. 1215-1228. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 1215-1228 Mots-clés : Assessment  Monitoring  Nonstationary  processes  Earthquake  engineering  Diagnosis  Structural  failures  Frequency  analysis  Natural  frequency Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper introduces three wavelet-based damage-sensitive features (DSFs) extracted from structural responses recorded during earthquakes to diagnose structural damage. Because earthquake excitations are nonstationary, the wavelet transform, which represents data as a weighted sum of time-localized waves, is used to model the structural responses. These DSFs are defined as functions of wavelet energies at particular frequencies and specific times. The first DSF (DSF1) indicates how the wavelet energy at the original natural frequency of the structure changes as the damage progresses. The second DSF (DSF2) indicates how much the wavelet energy is spread out in time. The third DSF (DSF3) reflects how slowly the wavelet energy decays with time. The performance of these DSFs is validated using two sets of shake-table test data. The results show that as the damage extent increases, the DSF1 value decreases and the DSF2 and DSF3 values increase. Thus, these DSFs can be used to diagnose structural damage. The robustness of these DSFs to different input ground motions is also investigated using a set of simulated data. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i10/p1215_s1?isAuthorized=no