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Ajouter le résultat dans votre panierEstimation of load reduction factors for clay masonry walls / Francesca Da Porto in Earthquake engineering structural dynamics, Vol. 38 N° 10 (Août 2009)
Titre : Estimation of load reduction factors for clay masonry walls Type de document : texte imprimé Auteurs : Francesca Da Porto, Auteur ; Manuel Grendene, Auteur ; Claudio Modena, Auteur Article en page(s) : pp. 1155-1174 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : unreinforced masonry Cyclic behaviour Dynamic analyses Load reduction factor Résumé : The in-plane cyclic behaviour of three types of unreinforced clay masonry was characterized by means of laboratory tests on full-scale specimens. The masonry walls were assembled with various bonding arrangements (head joints made with mortar pockets, dry head joints with mechanical interlocking, thin-layer mortar bed joints), which are not yet inserted in seismic codes. Experimental behaviour was modelled with an analytical hysteretic model able to predict lateral load-displacement curves in case of shear failure of the unreinforced walls. According to the experimental results and those of the selected analytical model, parametric study to evaluate the reduction in lateral strength demand produced by non-linear behaviour in masonry walls, i.e. the load reduction factor was carried out by non-linear dynamic analyses. The calculated values of the load reduction factor were modest. The differences in values found for the three masonry types, although consistent with them, were not great. This may indicate that, in the ultimate limit state, the type of masonry cannot significantly affect the behaviour of an entire building. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1155-1174[article] Estimation of load reduction factors for clay masonry walls [texte imprimé] / Francesca Da Porto, Auteur ; Manuel Grendene, Auteur ; Claudio Modena, Auteur . - pp. 1155-1174.
Génie Civil
Langues : Anglais (eng)
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1155-1174
Mots-clés : unreinforced masonry Cyclic behaviour Dynamic analyses Load reduction factor Résumé : The in-plane cyclic behaviour of three types of unreinforced clay masonry was characterized by means of laboratory tests on full-scale specimens. The masonry walls were assembled with various bonding arrangements (head joints made with mortar pockets, dry head joints with mechanical interlocking, thin-layer mortar bed joints), which are not yet inserted in seismic codes. Experimental behaviour was modelled with an analytical hysteretic model able to predict lateral load-displacement curves in case of shear failure of the unreinforced walls. According to the experimental results and those of the selected analytical model, parametric study to evaluate the reduction in lateral strength demand produced by non-linear behaviour in masonry walls, i.e. the load reduction factor was carried out by non-linear dynamic analyses. The calculated values of the load reduction factor were modest. The differences in values found for the three masonry types, although consistent with them, were not great. This may indicate that, in the ultimate limit state, the type of masonry cannot significantly affect the behaviour of an entire building. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe Exemplaires
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Titre : Seismic evaluation of 1940s asymmetric wood-frame building using conventional measurements and high-definition laser scanning Type de document : texte imprimé Auteurs : Khalid M. Mosalam, Auteur ; Shakhzod M. Takhirov, Auteur ; Alidad Hashemi, Auteur Article en page(s) : pp. 1175-1197 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : House-over-garage Laser scan Shake table. Soft story Torsion Wood-frame Résumé : This study presents results from shake table experiments of a wood-frame building conducted at the University of California, Berkeley. A 13.5-ft × 19.5-ft two-story wood-frame building representing San Francisco 1940s design of a residential building with a garage space on the first story (house-over-garage) was tested. The test building was subjected to scaled ground motion based on Los Gatos record from Loma Prieta 1989 earthquake. The strong motion time history was scaled to match design spectra of a site in Richmond district of San Francisco. The test results demonstrated the seismic vulnerability of the test building due to soft story mechanism and significant twisting when shaken in two horizontal directions. In addition to conventional instrumentation for measuring acceleration and position of selected points of the test building, high-definition laser scanning technology was employed to assess global and local anomalies of the building after the shake table tests. The analysis conducted in this study showed very good correlation between conventional data recorded from position transducers and the laser scans. These laser scans expanded limits of conventional data at discrete points and allowed analyzing the whole building after shaking. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1175-1197[article] Seismic evaluation of 1940s asymmetric wood-frame building using conventional measurements and high-definition laser scanning [texte imprimé] / Khalid M. Mosalam, Auteur ; Shakhzod M. Takhirov, Auteur ; Alidad Hashemi, Auteur . - pp. 1175-1197.
Génie Civil
Langues : Anglais (eng)
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1175-1197
Mots-clés : House-over-garage Laser scan Shake table. Soft story Torsion Wood-frame Résumé : This study presents results from shake table experiments of a wood-frame building conducted at the University of California, Berkeley. A 13.5-ft × 19.5-ft two-story wood-frame building representing San Francisco 1940s design of a residential building with a garage space on the first story (house-over-garage) was tested. The test building was subjected to scaled ground motion based on Los Gatos record from Loma Prieta 1989 earthquake. The strong motion time history was scaled to match design spectra of a site in Richmond district of San Francisco. The test results demonstrated the seismic vulnerability of the test building due to soft story mechanism and significant twisting when shaken in two horizontal directions. In addition to conventional instrumentation for measuring acceleration and position of selected points of the test building, high-definition laser scanning technology was employed to assess global and local anomalies of the building after the shake table tests. The analysis conducted in this study showed very good correlation between conventional data recorded from position transducers and the laser scans. These laser scans expanded limits of conventional data at discrete points and allowed analyzing the whole building after shaking. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe Exemplaires
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Titre : HDR devices for the seismic protection of frame structures: Experimental results and numerical simulations Type de document : texte imprimé Auteurs : Ragni, Laura, Auteur ; Luigino Dezi, Auteur ; Dall'Asta, Andrea, Auteur ; Leoni Graziano Article en page(s) : pp. 1199-1217 Note générale : Génie civil Langues : Anglais (eng) Mots-clés : Passive control High damping rubber Dissipative bracings Résumé : As part of a national research programme an experimental campaign was carried out on a real scale mock-up consisting of a steel-concrete composite frame equipped with dissipative bracings, based on high damping rubber (HDR) devices. Free vibration tests, followed by force-controlled and displacement-controlled cyclic tests were performed. The experimental tests were aimed at studying the dynamic response of the coupled system in order to demonstrate the effectiveness of HDR devices in increasing the stiffness and dissipation capacity of the frame and investigating the ability of the constitutive HDR model proposed by the authors to predict the dynamic response of the coupled system. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1199-1217[article] HDR devices for the seismic protection of frame structures: Experimental results and numerical simulations [texte imprimé] / Ragni, Laura, Auteur ; Luigino Dezi, Auteur ; Dall'Asta, Andrea, Auteur ; Leoni Graziano . - pp. 1199-1217.
Génie civil
Langues : Anglais (eng)
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1199-1217
Mots-clés : Passive control High damping rubber Dissipative bracings Résumé : As part of a national research programme an experimental campaign was carried out on a real scale mock-up consisting of a steel-concrete composite frame equipped with dissipative bracings, based on high damping rubber (HDR) devices. Free vibration tests, followed by force-controlled and displacement-controlled cyclic tests were performed. The experimental tests were aimed at studying the dynamic response of the coupled system in order to demonstrate the effectiveness of HDR devices in increasing the stiffness and dissipation capacity of the frame and investigating the ability of the constitutive HDR model proposed by the authors to predict the dynamic response of the coupled system. DEWEY : 624.1 ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe Exemplaires
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Titre : Damage identification of a 3D full scale steel-concrete composite structure with partial-strength joints at different pseudo-dynamic load levels Type de document : texte imprimé Auteurs : M. Molinari, Auteur ; A. T. Savadkoohi, Auteur ; O. S. Bursi, Auteur Article en page(s) : pp. 1219-1236 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Damage assessment Pseudo-dynamic tests Model updating Sensitivity analysis Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Partial-strength composite steel-concrete moment-resisting (MR) frame structures represent an open research field in seismic design from both a theoretical and an experimental standpoint. Among experimental techniques, vibration testing is a well-known and powerful technique for damage detection, localization and quantification, where actual modal parameters of a structure at different states can be determined from test data by using system identification methods. However, the identification of semi-rigid connections in framed structures is limited, and hence this paper focuses on a series of vibration experiments that were carried out on a realistic MR frame structure, following the application of pseudo-dynamic and quasi-static cyclic loadings at the European laboratory for structural assessment of the Joint Research Centre at Ispra, Italy, with the scope of understanding the structural behaviour and identifying changes in the dynamic response. From the forced vibration response, natural frequencies, damping ratios, modal displacements and rotations were extracted using the circle fitting technique. These modal parameters were used for local and global damage identification by updating a 3D finite element model of the intact structure. The identified results were then correlated with observations performed on the structure to understand further the underlying damage mechanisms. Finally, the latin hypercube sampling technique, a variant of the Monte Carlo method, was employed in order to study the sensitivity of the updated parameters of the 3D model to noise on the modal inputs. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1219-1236[article] Damage identification of a 3D full scale steel-concrete composite structure with partial-strength joints at different pseudo-dynamic load levels [texte imprimé] / M. Molinari, Auteur ; A. T. Savadkoohi, Auteur ; O. S. Bursi, Auteur . - pp. 1219-1236.
Génie Civil
Langues : Anglais (eng)
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1219-1236
Mots-clés : Damage assessment Pseudo-dynamic tests Model updating Sensitivity analysis Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Partial-strength composite steel-concrete moment-resisting (MR) frame structures represent an open research field in seismic design from both a theoretical and an experimental standpoint. Among experimental techniques, vibration testing is a well-known and powerful technique for damage detection, localization and quantification, where actual modal parameters of a structure at different states can be determined from test data by using system identification methods. However, the identification of semi-rigid connections in framed structures is limited, and hence this paper focuses on a series of vibration experiments that were carried out on a realistic MR frame structure, following the application of pseudo-dynamic and quasi-static cyclic loadings at the European laboratory for structural assessment of the Joint Research Centre at Ispra, Italy, with the scope of understanding the structural behaviour and identifying changes in the dynamic response. From the forced vibration response, natural frequencies, damping ratios, modal displacements and rotations were extracted using the circle fitting technique. These modal parameters were used for local and global damage identification by updating a 3D finite element model of the intact structure. The identified results were then correlated with observations performed on the structure to understand further the underlying damage mechanisms. Finally, the latin hypercube sampling technique, a variant of the Monte Carlo method, was employed in order to study the sensitivity of the updated parameters of the 3D model to noise on the modal inputs. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe Exemplaires
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Titre : Improving the inverse compensation method for real-time hybrid simulation through a dual compensation scheme Type de document : texte imprimé Auteurs : Cheng Chen, Auteur ; James M. Ricles, Auteur Article en page(s) : pp. 1237-1255 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Real-time Hybrid simulation Actuator delay delay compensation Frequency response Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Real-time hybrid simulation combines experimental testing of physical substructure(s) and numerical simulation of analytical substructure(s), and thus enables the complete structural system to be considered during an experiment. Servo-hydraulic actuators are typically used to apply the command displacements to the physical substructure(s). Inaccuracy and instability can occur during a real-time hybrid simulation if the actuator delay due to servo-hydraulic dynamics is not properly compensated. Inverse compensation is a means to negate actuator delay due to inherent servo-hydraulic actuator dynamics during a real-time hybrid simulation. The success of inverse compensation requires the use of a known accurate value for the actuator delay. The actual actuator delay however may not be known before the simulation. An estimation based on previous experience has to be used, possibly leading to inaccurate experimental results. This paper presents a dual compensation scheme to improve the performance of the inverse compensation method when an inaccurately estimated actuator delay is used in the method. The dual compensation scheme modifies the predicted displacement from the inverse compensation procedure using the actuator tracking error. Frequency response analysis shows that the dual compensation scheme enables the inverse compensation method to compensate for actuator delay over a range of frequencies when an inaccurately estimated actuator delay is utilized. Real-time hybrid simulations of a single-degree-of-freedom system with an elastomeric damper are conducted to experimentally demonstrate the effectiveness of the dual compensation scheme. Exceptional experimental results are shown to be achieved using the dual compensation scheme without the knowledge of the actual actuator delay a priori. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1237-1255[article] Improving the inverse compensation method for real-time hybrid simulation through a dual compensation scheme [texte imprimé] / Cheng Chen, Auteur ; James M. Ricles, Auteur . - pp. 1237-1255.
Génie Civil
Langues : Anglais (eng)
in Earthquake engineering structural dynamics > Vol. 38 N° 10 (Août 2009) . - pp. 1237-1255
Mots-clés : Real-time Hybrid simulation Actuator delay delay compensation Frequency response Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Real-time hybrid simulation combines experimental testing of physical substructure(s) and numerical simulation of analytical substructure(s), and thus enables the complete structural system to be considered during an experiment. Servo-hydraulic actuators are typically used to apply the command displacements to the physical substructure(s). Inaccuracy and instability can occur during a real-time hybrid simulation if the actuator delay due to servo-hydraulic dynamics is not properly compensated. Inverse compensation is a means to negate actuator delay due to inherent servo-hydraulic actuator dynamics during a real-time hybrid simulation. The success of inverse compensation requires the use of a known accurate value for the actuator delay. The actual actuator delay however may not be known before the simulation. An estimation based on previous experience has to be used, possibly leading to inaccurate experimental results. This paper presents a dual compensation scheme to improve the performance of the inverse compensation method when an inaccurately estimated actuator delay is used in the method. The dual compensation scheme modifies the predicted displacement from the inverse compensation procedure using the actuator tracking error. Frequency response analysis shows that the dual compensation scheme enables the inverse compensation method to compensate for actuator delay over a range of frequencies when an inaccurately estimated actuator delay is utilized. Real-time hybrid simulations of a single-degree-of-freedom system with an elastomeric damper are conducted to experimentally demonstrate the effectiveness of the dual compensation scheme. Exceptional experimental results are shown to be achieved using the dual compensation scheme without the knowledge of the actual actuator delay a priori. ISSN : 0098-8847 En ligne : www.interscience.wiley.com/journal/eqe Exemplaires
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