Documents disponibles écrits par cet auteur

Cyclic quasi-static testing of hollow structural section beam members / Matthew Fadden in Journal of structural engineering, Vol. 138 N° 5 (Mai 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 5 (Mai 2012) . - pp. 561–570. Titre : Cyclic quasi-static testing of hollow structural section beam members Type de document : texte imprimé Auteurs : Matthew Fadden, Auteur ; Jason McCormick, Auteur Année de publication : 2012 Article en page(s) : pp. 561–570. Note générale : Génie civil Langues : Anglais (eng) Mots-clés : Hollow  sections  Cyclic  tests  Bending  Beams  Seismic  effects Résumé : The efficient compression, torsion, and bending behavior of hollow structural sections (HSS) combined with their high strength-to-weight ratio provide an opportunity to further their use in seismic applications and improve on structural performance. However, current applications of HSS in seismic systems are restricted because of a limited understanding of their cyclic bending behavior. To characterize the behavior of HSS under pure bending and determine limiting values for their use up to large rotation levels, 11 different HSS beam members ranging in size from HSS 203.2×101.6×6.4  mm to HSS 304.8×152.4×6.4  mm with thickness of 6.4 and 9.5 mm are tested under cyclic bending loads. The moment-rotation results suggest that the width-thickness and depth-thickness ratios are important in determining whether a stable plastic hinge can be sustained during cycling, ensuring adequate ductility. Cycling effects associated with increasing rotation levels and multiple cycles at the same level are considered with respect to the degradation of the moment capacity, rotation capacity, secant stiffness, and energy dissipation. It is clear that the influence of the width-thickness ratio and depth-thickness ratio is not independent of one other. Flange strains also provide an understanding of how yielding propagates along the length of the member and at what point local buckling begins to occur. In general, the findings suggest that HSS can be used in cyclic bending applications provided that their parameters are selected carefully to ensure stable plastic hinging behavior. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000506 [article] Cyclic quasi-static testing of hollow structural section beam members [texte imprimé] / Matthew Fadden, Auteur ; Jason McCormick, Auteur . - 2012 . - pp. 561–570. Génie civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 5 (Mai 2012) . - pp. 561–570. Mots-clés : Hollow  sections  Cyclic  tests  Bending  Beams  Seismic  effects Résumé : The efficient compression, torsion, and bending behavior of hollow structural sections (HSS) combined with their high strength-to-weight ratio provide an opportunity to further their use in seismic applications and improve on structural performance. However, current applications of HSS in seismic systems are restricted because of a limited understanding of their cyclic bending behavior. To characterize the behavior of HSS under pure bending and determine limiting values for their use up to large rotation levels, 11 different HSS beam members ranging in size from HSS 203.2×101.6×6.4  mm to HSS 304.8×152.4×6.4  mm with thickness of 6.4 and 9.5 mm are tested under cyclic bending loads. The moment-rotation results suggest that the width-thickness and depth-thickness ratios are important in determining whether a stable plastic hinge can be sustained during cycling, ensuring adequate ductility. Cycling effects associated with increasing rotation levels and multiple cycles at the same level are considered with respect to the degradation of the moment capacity, rotation capacity, secant stiffness, and energy dissipation. It is clear that the influence of the width-thickness ratio and depth-thickness ratio is not independent of one other. Flange strains also provide an understanding of how yielding propagates along the length of the member and at what point local buckling begins to occur. In general, the findings suggest that HSS can be used in cyclic bending applications provided that their parameters are selected carefully to ensure stable plastic hinging behavior. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000506

Investigation of the sliding behavior between steel and mortar for seismic applications in structures / Jason McCormick in Earthquake engineering structural dynamics, Vol. 38 N° 12 (Octobre 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 12 (Octobre 2009) . - pp. 1401-1419 Titre : Investigation of the sliding behavior between steel and mortar for seismic applications in structures Type de document : texte imprimé Auteurs : Jason McCormick, Auteur ; Nagae, Takuya, Auteur ; Masahiro Ikenaga Article en page(s) : pp. 1401-1419 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Friction;  steel;  Mortar;  Steel  structures;  Shake  table  tests;  Seismic Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The friction developed between a steel base plate and a mortar base contributes shear resistance to the building system during a seismic event. In order to investigate the possible sliding behavior between the base plate and the mortar, a shake table study is undertaken using a large rigid mass supported by steel contact elements which rest on mortar surfaces connected to the shake table. Horizontal input accelerations are considered at various magnitudes and frequencies. The results provide a constant friction coefficient during sliding with an average value of approximately 0.78. A theoretical formulation of the friction behavior is also undertaken. The theoretical equations show that the sliding behavior is dependent on the ratio of the friction force to the input force. The addition of vertical accelerations to the system further complicates the sliding behavior as a result of the varying normal force. This results in a variable friction resistance which is a function of the amplitude, phase, and frequency of the horizontal and vertical input motions. In general, this study showed a consistent and reliable sliding behavior between steel and mortar. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe [article] Investigation of the sliding behavior between steel and mortar for seismic applications in structures [texte imprimé] / Jason McCormick, Auteur ; Nagae, Takuya, Auteur ; Masahiro Ikenaga . - pp. 1401-1419. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 12 (Octobre 2009) . - pp. 1401-1419 Mots-clés : Friction;  steel;  Mortar;  Steel  structures;  Shake  table  tests;  Seismic Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : The friction developed between a steel base plate and a mortar base contributes shear resistance to the building system during a seismic event. In order to investigate the possible sliding behavior between the base plate and the mortar, a shake table study is undertaken using a large rigid mass supported by steel contact elements which rest on mortar surfaces connected to the shake table. Horizontal input accelerations are considered at various magnitudes and frequencies. The results provide a constant friction coefficient during sliding with an average value of approximately 0.78. A theoretical formulation of the friction behavior is also undertaken. The theoretical equations show that the sliding behavior is dependent on the ratio of the friction force to the input force. The addition of vertical accelerations to the system further complicates the sliding behavior as a result of the varying normal force. This results in a variable friction resistance which is a function of the amplitude, phase, and frequency of the horizontal and vertical input motions. In general, this study showed a consistent and reliable sliding behavior between steel and mortar. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe

Structural engineering with NiTi . II / Jason McCormick in Journal of engineering mechanics, Vol. 133 N°9 (Septembre 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°9 (Septembre 2007) . - pp.1019–1029. Titre : Structural engineering with NiTi . II : mechanical behavior and scaling Type de document : texte imprimé Auteurs : Jason McCormick, Auteur ; Jeff Tyber, Auteur ; Reginald DesRoches, Auteur Année de publication : 2007 Article en page(s) : pp.1019–1029. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Shape  memory  effect,  Structures,  Material  tests,  Material  properties  Mechanical  properties  Cyclic  tests  Earthquake  engineering Résumé : This paper continues to address the overarching goal to provide a more unified understanding of NiTi shape memory alloys intended for use in structural applications by attempting to link standard processing practice and basic materials characterization to the deformation behavior of large diameter bars. Results from cyclic tensile tests performed on large diameter Ni-rich polycrystalline NiTi bars are presented. Coupon specimens taken from deformation processed bars with diameters of 12.7, 19.1, and 31.8mm are tested along with their respective full-scale specimens. The coupon tests results reveal small and highly variable differences between specimens taken from the different size bars. The full-scale specimen tests continue to show the presence of the R phase, but lack a Lüders-like transformation. A comparison of the results suggests that coupon specimens provide only limited information in terms of the full-scale behavior. Full-scale tests using an earthquake-type loading then show similar behavior to the tensile cyclic tests suggesting the ability to use NiTi in structural applications. Overall, this paper and Tyber et al. 2007 provide a multiscale analysis of NiTi shape memory alloys to be used by both material scientist and civil engineers in the development of applications for NiTi. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=1019&volume=133&issue=9&journalC [...] [article] Structural engineering with NiTi . II : mechanical behavior and scaling [texte imprimé] / Jason McCormick, Auteur ; Jeff Tyber, Auteur ; Reginald DesRoches, Auteur . - 2007 . - pp.1019–1029. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°9 (Septembre 2007) . - pp.1019–1029. Mots-clés : Shape  memory  effect,  Structures,  Material  tests,  Material  properties  Mechanical  properties  Cyclic  tests  Earthquake  engineering Résumé : This paper continues to address the overarching goal to provide a more unified understanding of NiTi shape memory alloys intended for use in structural applications by attempting to link standard processing practice and basic materials characterization to the deformation behavior of large diameter bars. Results from cyclic tensile tests performed on large diameter Ni-rich polycrystalline NiTi bars are presented. Coupon specimens taken from deformation processed bars with diameters of 12.7, 19.1, and 31.8mm are tested along with their respective full-scale specimens. The coupon tests results reveal small and highly variable differences between specimens taken from the different size bars. The full-scale specimen tests continue to show the presence of the R phase, but lack a Lüders-like transformation. A comparison of the results suggests that coupon specimens provide only limited information in terms of the full-scale behavior. Full-scale tests using an earthquake-type loading then show similar behavior to the tensile cyclic tests suggesting the ability to use NiTi in structural applications. Overall, this paper and Tyber et al. 2007 provide a multiscale analysis of NiTi shape memory alloys to be used by both material scientist and civil engineers in the development of applications for NiTi. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=1019&volume=133&issue=9&journalC [...]