Dépouillements

Experimental study of high-strength cold-formed stiffened-web c-sections in compression / Derrick C. Y. Yap in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 162-172 Titre : Experimental study of high-strength cold-formed stiffened-web c-sections in compression Type de document : texte imprimé Auteurs : Derrick C. Y. Yap, Auteur ; Gregory J. Hancock, Auteur Année de publication : 2011 Article en page(s) : pp. 162-172 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cold  formed  High-strength  steel  Local  buckling  Distortional  buckling  Interaction  buckling  Postbuckling  behavior  Intermediately  stiffened  section Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : High-strength cold-formed steel sections are commonly used in a variety of applications including residential construction. These steel sections typically have a nominal yield stress of 550 MPa and the use of such high-strength material allows for a reduction in thicknesses. With this reduction in thickness, the high-strength steel can be manufactured into complex shapes including stiffeners. Such complex shapes exhibit structural instabilities such as local, distortional, and flexural-torsional buckling modes, and in some cases, interaction of the local and distortional buckling modes may occur. This paper describes the design and testing of web-stiffened high-strength steel cold-formed lipped channel columns. In order to be able to apply the direct strength method (DSM) in Section 7 of the Australian Standard AS/NZS 4600:2005 and Appendix 1 of the North American Specification to design, the steel sections must be prequalified as a compression member. The section chosen is prequalified and has nearly coincidental local buckling and distortional buckling loads as well as a flexural-torsional mode which varies with length. A series of compression tests was carried out in a 300-kN capacity SINTEC testing machine over a range of lengths with fixed-ended conditions. The varying lengths were chosen so as to observe the buckling modes and the possibility of interaction between them. The effect of the different types of failure modes is also discussed in this paper. The experimental results are then compared with design methods in the existing design standards. The methods include the effective width method and the DSM as described in the Australian Cold-Formed Steel Structures Standard and the North American Specification. It is shown that the existing standards are unconservative and new proposals for dealing with this are made. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p162_s1?isAuthorized=no [article] Experimental study of high-strength cold-formed stiffened-web c-sections in compression [texte imprimé] / Derrick C. Y. Yap, Auteur ; Gregory J. Hancock, Auteur . - 2011 . - pp. 162-172. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 162-172 Mots-clés : Cold  formed  High-strength  steel  Local  buckling  Distortional  buckling  Interaction  buckling  Postbuckling  behavior  Intermediately  stiffened  section Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : High-strength cold-formed steel sections are commonly used in a variety of applications including residential construction. These steel sections typically have a nominal yield stress of 550 MPa and the use of such high-strength material allows for a reduction in thicknesses. With this reduction in thickness, the high-strength steel can be manufactured into complex shapes including stiffeners. Such complex shapes exhibit structural instabilities such as local, distortional, and flexural-torsional buckling modes, and in some cases, interaction of the local and distortional buckling modes may occur. This paper describes the design and testing of web-stiffened high-strength steel cold-formed lipped channel columns. In order to be able to apply the direct strength method (DSM) in Section 7 of the Australian Standard AS/NZS 4600:2005 and Appendix 1 of the North American Specification to design, the steel sections must be prequalified as a compression member. The section chosen is prequalified and has nearly coincidental local buckling and distortional buckling loads as well as a flexural-torsional mode which varies with length. A series of compression tests was carried out in a 300-kN capacity SINTEC testing machine over a range of lengths with fixed-ended conditions. The varying lengths were chosen so as to observe the buckling modes and the possibility of interaction between them. The effect of the different types of failure modes is also discussed in this paper. The experimental results are then compared with design methods in the existing design standards. The methods include the effective width method and the DSM as described in the Australian Cold-Formed Steel Structures Standard and the North American Specification. It is shown that the existing standards are unconservative and new proposals for dealing with this are made. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p162_s1?isAuthorized=no

Local buckling of aluminum alloy angles under uniform compression / Federico M. Mazzolani in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 173-184 Titre : Local buckling of aluminum alloy angles under uniform compression Type de document : texte imprimé Auteurs : Federico M. Mazzolani, Auteur ; Piluso, Vincenzo, Auteur ; Gianvittorio Rizzano, Auteur Année de publication : 2011 Article en page(s) : pp. 173-184 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Aluminum  members  Local  buckling  Stub  column  tests  Cross-section  classification  Effective  width  Effective  thickness Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Metal members are able to exhibit plastic deformations whose amplitude depends on the local slenderness of the plate elements constituting the member section, provided that global instabilities are prevented. This local slenderness depends on the width-to-thickness ratios of the plate elements and governs the occurrence of local buckling which can be developed either in elastic or in plastic range. Aiming at the development of a ductile behavior, the occurrence of local buckling in elastic range has to be prevented to assure the development of ultimate behavior in plastic range. To this scope, the width-to-thickness ratios of the plate elements constituting the member section have to be properly limited. Wide experimental research dealing with the influence of width-to-thickness ratios on the local buckling of heat-treated aluminum alloys has been recently completed with the aim of providing Eurocode 9 with the background data necessary for setting up classification criteria specific to aluminum members. The aim of the developed experimental activity is evaluation of the relationship between the strain corresponding to the complete development of local buckling and the slenderness parameters of the plate elements composing the section. This relationship has been derived by analyzing the results obtained from a great number of stub column tests carried out on specimens having width-to-thickness ratios covering the whole range of variability of commonly extruded profiles. The whole experimental program has dealt with square hollow section, rectangular hollow section members, channels, and angles made of 6,000 series alloy, provided by the major European aluminum industries. This paper presents and discusses the results of the part of the experimental program regarding aluminum alloy angles subjected to local buckling under uniform compression. Sixty-four stub column tests have been carried out at the Material and Structure Laboratory of the Department of Civil Engineering of Salerno University. These experimental results and their interpretation are presented in this paper. In addition, a classification criterion accounting for the interaction between the two slenderness parameters of the cross-section is proposed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p173_s1?isAuthorized=no [article] Local buckling of aluminum alloy angles under uniform compression [texte imprimé] / Federico M. Mazzolani, Auteur ; Piluso, Vincenzo, Auteur ; Gianvittorio Rizzano, Auteur . - 2011 . - pp. 173-184. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 173-184 Mots-clés : Aluminum  members  Local  buckling  Stub  column  tests  Cross-section  classification  Effective  width  Effective  thickness Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Metal members are able to exhibit plastic deformations whose amplitude depends on the local slenderness of the plate elements constituting the member section, provided that global instabilities are prevented. This local slenderness depends on the width-to-thickness ratios of the plate elements and governs the occurrence of local buckling which can be developed either in elastic or in plastic range. Aiming at the development of a ductile behavior, the occurrence of local buckling in elastic range has to be prevented to assure the development of ultimate behavior in plastic range. To this scope, the width-to-thickness ratios of the plate elements constituting the member section have to be properly limited. Wide experimental research dealing with the influence of width-to-thickness ratios on the local buckling of heat-treated aluminum alloys has been recently completed with the aim of providing Eurocode 9 with the background data necessary for setting up classification criteria specific to aluminum members. The aim of the developed experimental activity is evaluation of the relationship between the strain corresponding to the complete development of local buckling and the slenderness parameters of the plate elements composing the section. This relationship has been derived by analyzing the results obtained from a great number of stub column tests carried out on specimens having width-to-thickness ratios covering the whole range of variability of commonly extruded profiles. The whole experimental program has dealt with square hollow section, rectangular hollow section members, channels, and angles made of 6,000 series alloy, provided by the major European aluminum industries. This paper presents and discusses the results of the part of the experimental program regarding aluminum alloy angles subjected to local buckling under uniform compression. Sixty-four stub column tests have been carried out at the Material and Structure Laboratory of the Department of Civil Engineering of Salerno University. These experimental results and their interpretation are presented in this paper. In addition, a classification criterion accounting for the interaction between the two slenderness parameters of the cross-section is proposed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p173_s1?isAuthorized=no

SANISTEEL: Simple anisotropic steel plasticity model / Mark Mahan in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 185-194 Titre : SANISTEEL: Simple anisotropic steel plasticity model Type de document : texte imprimé Auteurs : Mark Mahan, Auteur ; Dafalias, Yannis F., Auteur ; Mahdi Taiebat, Auteur Année de publication : 2011 Article en page(s) : pp. 185-194 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Steel  Anisotropy  Constitutive  model  Plateau  Perfect  plasticity  Bounding  surface Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A simple constitutive model for the inelastic response of steel under monotonic and random cyclic loading conditions is developed within the framework of bounding surface plasticity. The particular feature that distinguishes this model from other similar ones is the ability of the bounding surface formulation to describe in a very simple way the initial “plateau” type of perfectly plastic response that many kinds of structural steels exhibit upon initial yield in tension or compression, before hardening begins. The key constitutive element is to assume a fixed nonhardening bounding surface during the plateau response until a cumulative plastic strain threshold is reached, while the yield surface softens isotropically and hardens kinematically. In this way not only monotonic but also cyclic loading within the plateau range can be easily described. Three kinematic hardening rules for the bounding surface are explored. The development is focused on uniaxial loading conditions that are typical in many structural engineering applications employing a fiber-based discretization of the cross section. Several simulations to demonstrate the effectiveness of the proposed model are presented. Finally, its extension to a multiaxial stress generalization is concisely presented for future use. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p185_s1?isAuthorized=no [article] SANISTEEL: Simple anisotropic steel plasticity model [texte imprimé] / Mark Mahan, Auteur ; Dafalias, Yannis F., Auteur ; Mahdi Taiebat, Auteur . - 2011 . - pp. 185-194. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 185-194 Mots-clés : Steel  Anisotropy  Constitutive  model  Plateau  Perfect  plasticity  Bounding  surface Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A simple constitutive model for the inelastic response of steel under monotonic and random cyclic loading conditions is developed within the framework of bounding surface plasticity. The particular feature that distinguishes this model from other similar ones is the ability of the bounding surface formulation to describe in a very simple way the initial “plateau” type of perfectly plastic response that many kinds of structural steels exhibit upon initial yield in tension or compression, before hardening begins. The key constitutive element is to assume a fixed nonhardening bounding surface during the plateau response until a cumulative plastic strain threshold is reached, while the yield surface softens isotropically and hardens kinematically. In this way not only monotonic but also cyclic loading within the plateau range can be easily described. Three kinematic hardening rules for the bounding surface are explored. The development is focused on uniaxial loading conditions that are typical in many structural engineering applications employing a fiber-based discretization of the cross section. Several simulations to demonstrate the effectiveness of the proposed model are presented. Finally, its extension to a multiaxial stress generalization is concisely presented for future use. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p185_s1?isAuthorized=no

Constitutive model for cyclic response of structural steels with yield plateau / Alper Ucak in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 195-206 Titre : Constitutive model for cyclic response of structural steels with yield plateau Type de document : texte imprimé Auteurs : Alper Ucak, Auteur ; Panos Tsopelas, Auteur Année de publication : 2011 Article en page(s) : pp. 195-206 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cyclic  plasticity  Structural  steel  Yield  plateau  Nonlinear  kinematic  hardening  Cyclic Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A rate-independent cyclic plasticity model for structural steels with a yield plateau is proposed. The model couples nonlinear kinematic hardening with a memory surface in the plastic strain space, to account for the progressive cyclic hardening/softening effects and a pseudomemory surface in the deviatoric stress space to correctly describe the plateau response. A simple identification procedure to calibrate the material dependent parameters is outlined and the accuracy of the proposed model is verified against experimental data available in the literature for proportional and nonproportional loading paths. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p195_s1?isAuthorized=no [article] Constitutive model for cyclic response of structural steels with yield plateau [texte imprimé] / Alper Ucak, Auteur ; Panos Tsopelas, Auteur . - 2011 . - pp. 195-206. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 195-206 Mots-clés : Cyclic  plasticity  Structural  steel  Yield  plateau  Nonlinear  kinematic  hardening  Cyclic Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A rate-independent cyclic plasticity model for structural steels with a yield plateau is proposed. The model couples nonlinear kinematic hardening with a memory surface in the plastic strain space, to account for the progressive cyclic hardening/softening effects and a pseudomemory surface in the deviatoric stress space to correctly describe the plateau response. A simple identification procedure to calibrate the material dependent parameters is outlined and the accuracy of the proposed model is verified against experimental data available in the literature for proportional and nonproportional loading paths. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p195_s1?isAuthorized=no

Dynamic analysis of three-dimensional frames with material and geometric nonlinearities / M. Schachter in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 207-219 Titre : Dynamic analysis of three-dimensional frames with material and geometric nonlinearities Type de document : texte imprimé Auteurs : M. Schachter, Auteur ; Reinhorn, A. M., Auteur Année de publication : 2011 Article en page(s) : pp. 207-219 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Dynamic  analysis  Material  nonlinearities  Geometric  nonlinearities  Corotational  approach  State  space  approach Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The dynamic analysis of inelastic structures with geometric nonlinearities experiencing large deformations and buckling is challenging, in particular, if three-dimensional space effects are considered. This paper introduces a new formulation of a three-dimensional beam-column element and the associated analysis of the global frame system using a corotational approach formulated in the state space. The corotational approach may allow uncoupling of the local large deformations and inelastic buckling of the element from the large deformation of the global system. Shaking table testing performed by the authors on a steel frame model structure provides benchmark information for comparison with the proposed analytical formulation. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p207_s1?isAuthorized=no [article] Dynamic analysis of three-dimensional frames with material and geometric nonlinearities [texte imprimé] / M. Schachter, Auteur ; Reinhorn, A. M., Auteur . - 2011 . - pp. 207-219. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 207-219 Mots-clés : Dynamic  analysis  Material  nonlinearities  Geometric  nonlinearities  Corotational  approach  State  space  approach Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The dynamic analysis of inelastic structures with geometric nonlinearities experiencing large deformations and buckling is challenging, in particular, if three-dimensional space effects are considered. This paper introduces a new formulation of a three-dimensional beam-column element and the associated analysis of the global frame system using a corotational approach formulated in the state space. The corotational approach may allow uncoupling of the local large deformations and inelastic buckling of the element from the large deformation of the global system. Shaking table testing performed by the authors on a steel frame model structure provides benchmark information for comparison with the proposed analytical formulation. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p207_s1?isAuthorized=no

Out-of-plane free vibration analysis of a horizontally circular curved beam carrying arbitrary sets of concentrated elements / Jong-Shyong Wu in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 220-241 Titre : Out-of-plane free vibration analysis of a horizontally circular curved beam carrying arbitrary sets of concentrated elements Type de document : texte imprimé Auteurs : Jong-Shyong Wu, Auteur ; Yung-Chuan Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 220-241 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bare  curved  beam  Loaded  curved  beam  Concentrated  elements  Natural  frequency  Mode  shape  Exact  solution Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : For convenience, a horizontally circular curved beam without any attachments is called a “bare” curved beam and the one carrying any attachments is called a “loaded” curved beam, in this paper. For the out-of-plane free vibrations of bare curved beams, one can find some exact solutions from the existing literature, but this is not true for those of the loaded curved beams. One of the main reasons for the last situation is due to the difficulty of solving a complex-variable eigenvalue equation. It is well known that the half-interval method is one of the simplest techniques for searching the roots of an eigenvalue equation. However, it suffers difficulty if the eigenvalue equation is a determinant form (|H(ω)| = 0) with some (or all) of its coefficients [Hi,j(ω)] being the complex numbers, because it is difficult to find a trial root (ωt) so that both the real part HR and imaginary part HI of the associated determinant value |H(ωt)| are equal to zero simultaneously (i.e., HR = HI = 0). Furthermore, the magnitude of the determinant value is greater than or equal to zero (i.e., math = math ≥ 0). To overcome the last difficulty, this paper presents a technique to replace all complex coefficients of the eigenvalue equation by the real ones, so that the conventional half-interval method may be easily applied to determining the “exact” solution for the natural frequencies and mode shapes of out-of-plane free vibrations of a uniform curved Euler-Bernoulli beam carrying arbitrary sets of concentrated elements in various boundary conditions, where each set of concentrated elements includes a lumped mass, a linear spring, a bending spring and a twisting (torsional) spring. To confirm the reliability of the presented theory and the developed computer program, most of the exact solutions for natural frequencies and mode shapes obtained from the presented approach are compared with the “approximate” ones obtained from the conventional finite-element method and good agreements are achieved. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p220_s1?isAuthorized=no [article] Out-of-plane free vibration analysis of a horizontally circular curved beam carrying arbitrary sets of concentrated elements [texte imprimé] / Jong-Shyong Wu, Auteur ; Yung-Chuan Chen, Auteur . - 2011 . - pp. 220-241. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 220-241 Mots-clés : Bare  curved  beam  Loaded  curved  beam  Concentrated  elements  Natural  frequency  Mode  shape  Exact  solution Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : For convenience, a horizontally circular curved beam without any attachments is called a “bare” curved beam and the one carrying any attachments is called a “loaded” curved beam, in this paper. For the out-of-plane free vibrations of bare curved beams, one can find some exact solutions from the existing literature, but this is not true for those of the loaded curved beams. One of the main reasons for the last situation is due to the difficulty of solving a complex-variable eigenvalue equation. It is well known that the half-interval method is one of the simplest techniques for searching the roots of an eigenvalue equation. However, it suffers difficulty if the eigenvalue equation is a determinant form (|H(ω)| = 0) with some (or all) of its coefficients [Hi,j(ω)] being the complex numbers, because it is difficult to find a trial root (ωt) so that both the real part HR and imaginary part HI of the associated determinant value |H(ωt)| are equal to zero simultaneously (i.e., HR = HI = 0). Furthermore, the magnitude of the determinant value is greater than or equal to zero (i.e., math = math ≥ 0). To overcome the last difficulty, this paper presents a technique to replace all complex coefficients of the eigenvalue equation by the real ones, so that the conventional half-interval method may be easily applied to determining the “exact” solution for the natural frequencies and mode shapes of out-of-plane free vibrations of a uniform curved Euler-Bernoulli beam carrying arbitrary sets of concentrated elements in various boundary conditions, where each set of concentrated elements includes a lumped mass, a linear spring, a bending spring and a twisting (torsional) spring. To confirm the reliability of the presented theory and the developed computer program, most of the exact solutions for natural frequencies and mode shapes obtained from the presented approach are compared with the “approximate” ones obtained from the conventional finite-element method and good agreements are achieved. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p220_s1?isAuthorized=no

Adaptive compensation for detuning in pendulum tuned mass dampers / A. J. Roffel in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 242-251 Titre : Adaptive compensation for detuning in pendulum tuned mass dampers Type de document : texte imprimé Auteurs : A. J. Roffel, Auteur ; R. Lourenco, Auteur ; S. Narasimhan, Auteur Année de publication : 2011 Article en page(s) : pp. 242-251 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Tuned  mass  dampers  Adaptive  TMDs  Passive  vibration  control  Structure  vibration  control Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Detuning, resulting from deterioration, inadvertent changes to structure properties, and design forecasting, can lead to a significant loss of performance in tuned mass dampers (TMDs). To overcome this issue, an adaptive compensation mechanism for suspended pendulum TMDs is proposed. The adaptive pendulum mass damper is a three-dimensional pendulum, augmented with a tuning frame to adjust its natural frequency, and two adjustable air dampers adjust damping. The adjustments for the natural frequency and damping compensation are achieved using a system of stepper motors and a microcontroller. There are two major components in the proposed methodology: identification and control, one followed by the other, in that order. The identification is carried out using spectral information obtained from the structural acceleration responses. The performance of the adaptive pendulum system is studied via both experiments and simulations. The main contribution of this paper is to develop an effective means of compensation for detuning in TMDs, while retaining the simplicity of passive pendulum TMDs. The proposed methodology allows pendulum TMDs to be tuned in place using relatively simple hardware and algorithms, based on ambient vibration measurements only. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p242_s1?isAuthorized=no [article] Adaptive compensation for detuning in pendulum tuned mass dampers [texte imprimé] / A. J. Roffel, Auteur ; R. Lourenco, Auteur ; S. Narasimhan, Auteur . - 2011 . - pp. 242-251. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 242-251 Mots-clés : Tuned  mass  dampers  Adaptive  TMDs  Passive  vibration  control  Structure  vibration  control Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Detuning, resulting from deterioration, inadvertent changes to structure properties, and design forecasting, can lead to a significant loss of performance in tuned mass dampers (TMDs). To overcome this issue, an adaptive compensation mechanism for suspended pendulum TMDs is proposed. The adaptive pendulum mass damper is a three-dimensional pendulum, augmented with a tuning frame to adjust its natural frequency, and two adjustable air dampers adjust damping. The adjustments for the natural frequency and damping compensation are achieved using a system of stepper motors and a microcontroller. There are two major components in the proposed methodology: identification and control, one followed by the other, in that order. The identification is carried out using spectral information obtained from the structural acceleration responses. The performance of the adaptive pendulum system is studied via both experiments and simulations. The main contribution of this paper is to develop an effective means of compensation for detuning in TMDs, while retaining the simplicity of passive pendulum TMDs. The proposed methodology allows pendulum TMDs to be tuned in place using relatively simple hardware and algorithms, based on ambient vibration measurements only. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p242_s1?isAuthorized=no

Analytical assessment of the effect of vertical earthquake motion on RC bridge piers / Sung Jig Kim in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 252-260 Titre : Analytical assessment of the effect of vertical earthquake motion on RC bridge piers Type de document : texte imprimé Auteurs : Sung Jig Kim, Auteur ; Curtis J. Holub, Auteur ; Amr S. Elnashai, Auteur Année de publication : 2011 Article en page(s) : pp. 252-260 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Vertical  loads  Ground  motion  Seismic  effects  Bridges  Piers  Shear  strength Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents analytical assessment of the effect of vertical earthquake ground motion on RC bridge piers. A bridge structure damaged during the Northridge Earthquake and a Federal Highway concept bridge design are examined. The effects of a suite of earthquake ground motion records with different vertical-to-horizontal peak acceleration ratios on the two bridges are presented and the results are compared with the case of horizontal-only excitation. The effects of arrival time interval between horizontal and vertical acceleration peaks are also reported and compared to the case of coincident motion. It is observed that the inclusion of the vertical component of ground motion has an important effect on the response at all levels and components. It is therefore concluded that vertical motion should be included in analysis for assessment and design, especially that there are no particular challenges impeding its inclusion. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p252_s1?isAuthorized=no [article] Analytical assessment of the effect of vertical earthquake motion on RC bridge piers [texte imprimé] / Sung Jig Kim, Auteur ; Curtis J. Holub, Auteur ; Amr S. Elnashai, Auteur . - 2011 . - pp. 252-260. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 252-260 Mots-clés : Vertical  loads  Ground  motion  Seismic  effects  Bridges  Piers  Shear  strength Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper presents analytical assessment of the effect of vertical earthquake ground motion on RC bridge piers. A bridge structure damaged during the Northridge Earthquake and a Federal Highway concept bridge design are examined. The effects of a suite of earthquake ground motion records with different vertical-to-horizontal peak acceleration ratios on the two bridges are presented and the results are compared with the case of horizontal-only excitation. The effects of arrival time interval between horizontal and vertical acceleration peaks are also reported and compared to the case of coincident motion. It is observed that the inclusion of the vertical component of ground motion has an important effect on the response at all levels and components. It is therefore concluded that vertical motion should be included in analysis for assessment and design, especially that there are no particular challenges impeding its inclusion. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p252_s1?isAuthorized=no

Experimental tests of notched and plate connectors for LVL-concrete composite beams / David Yeoh in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 261-269 Titre : Experimental tests of notched and plate connectors for LVL-concrete composite beams Type de document : texte imprimé Auteurs : David Yeoh, Auteur ; Massimo Fragiacomo, Auteur ; Mary de Franceschi, Auteur Année de publication : 2011 Article en page(s) : pp. 261-269 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Composite  structures  Timber  Concrete  Connections  Tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper reports the experimental results of symmetrical push-out tests performed on notched and toothed metal plate connectors for laminated veneer lumber (LVL)-concrete composite floor systems. The characteristic shear strength and slip moduli were evaluated for three types of connectors: (1) a 300-mm-long rectangular notch cut in the LVL joist and reinforced with a 16-mm-diameter lag screw; (2) a triangular notch reinforced with the same lag screw; and (3) two 333-mm-long toothed metal plates pressed in the lateral surface of two adjacent LVL joists. The shear force versus relative slip relationships are presented together with analytical prepeak and postpeak approximations which can be used to carry out nonlinear finite-element analyses of LVL-concrete composite beams. The failure mechanisms of the notched connections are also discussed. Analytical design formulas for shear-strength evaluation of notched connections derived in accordance with New Zealand Standards and Eurocodes are proposed based on four possible failure mechanisms. Good approximation was found if a slight modification of the Eurocodes formulas is introduced. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p261_s1?isAuthorized=no [article] Experimental tests of notched and plate connectors for LVL-concrete composite beams [texte imprimé] / David Yeoh, Auteur ; Massimo Fragiacomo, Auteur ; Mary de Franceschi, Auteur . - 2011 . - pp. 261-269. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 261-269 Mots-clés : Composite  structures  Timber  Concrete  Connections  Tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper reports the experimental results of symmetrical push-out tests performed on notched and toothed metal plate connectors for laminated veneer lumber (LVL)-concrete composite floor systems. The characteristic shear strength and slip moduli were evaluated for three types of connectors: (1) a 300-mm-long rectangular notch cut in the LVL joist and reinforced with a 16-mm-diameter lag screw; (2) a triangular notch reinforced with the same lag screw; and (3) two 333-mm-long toothed metal plates pressed in the lateral surface of two adjacent LVL joists. The shear force versus relative slip relationships are presented together with analytical prepeak and postpeak approximations which can be used to carry out nonlinear finite-element analyses of LVL-concrete composite beams. The failure mechanisms of the notched connections are also discussed. Analytical design formulas for shear-strength evaluation of notched connections derived in accordance with New Zealand Standards and Eurocodes are proposed based on four possible failure mechanisms. Good approximation was found if a slight modification of the Eurocodes formulas is introduced. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p261_s1?isAuthorized=no

Stress-block parameters for unconfined and confined concrete based on a unified stress-strain model / Madhu M. Karthik in Journal of structural engineering, Vol. 137 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 270-273 Titre : Stress-block parameters for unconfined and confined concrete based on a unified stress-strain model Type de document : texte imprimé Auteurs : Madhu M. Karthik, Auteur ; Mander, John B., Auteur Année de publication : 2011 Article en page(s) : pp. 270-273 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  Stress  strain  Stress  blocks  Confined  concrete  Moment  curvature Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Equations to obtain equivalent rectangular stress-block parameters for unconfined and confined concrete are derived for rapid (hand) analysis and design purposes. To overcome a shortcoming of existing commonly used stress-strain models that are not easy to integrate, a new stress-strain model is proposed and validated for a wide range of concrete strengths and confining stresses. The efficacy of the equivalent rectangular stress-block parameters is demonstrated for hand calculations in predicting key moment-curvature results for a confined concrete column. Results are compared with those obtained from a computational fiber-element analysis using the proposed stress-strain model and another widely used existing model; good agreement between the two is observed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p270_s1?isAuthorized=no [article] Stress-block parameters for unconfined and confined concrete based on a unified stress-strain model [texte imprimé] / Madhu M. Karthik, Auteur ; Mander, John B., Auteur . - 2011 . - pp. 270-273. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 2 (Fevrier 2011) . - pp. 270-273 Mots-clés : Concrete  Stress  strain  Stress  blocks  Confined  concrete  Moment  curvature Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Equations to obtain equivalent rectangular stress-block parameters for unconfined and confined concrete are derived for rapid (hand) analysis and design purposes. To overcome a shortcoming of existing commonly used stress-strain models that are not easy to integrate, a new stress-strain model is proposed and validated for a wide range of concrete strengths and confining stresses. The efficacy of the equivalent rectangular stress-block parameters is demonstrated for hand calculations in predicting key moment-curvature results for a confined concrete column. Results are compared with those obtained from a computational fiber-element analysis using the proposed stress-strain model and another widely used existing model; good agreement between the two is observed. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i2/p270_s1?isAuthorized=no

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