MATERIALS AND STRUCTURES/MATERIAUX ET CONSTRUCTIONS, Aug 1, 1996
Dans cet article, on presente les resultats d'un certain nombre d'essais a long terme (en... more Dans cet article, on presente les resultats d'un certain nombre d'essais a long terme (en traction simple et en flexion) effectues sur quatre sortes de pierres naturelles utilisees tres souvent autrefois en Italie pour la construction (le marbre blanc de Carrara, deux sortes de gres, la pierre de Florence et la "Pietraforte", ainsi que sur la pierre calcaire de Piobbico-Cesana). Les essais ont ete realises en appliquant de facon continue aux eprouvettes differentes fractions de charges "instantanees" de rupture, en relevant l'evolution de la deformation jusqu'a la rupture. En general, tous les essais ont montre un comportement caracterise par les trois phases classiques du fluage. En meme temps, on a constate une diminution de 60 % de la resistance, tant a la traction qu'a la flexion, par rapport a une duree d'essais peu superieure a un an. Cet article presente un modele constitutif phenomenologique permettant d'analyser le comportement visco-plastique observe. On indique ici, en vue d'applications techniques, une fonction de fluage qui permet l'evaluation directe des effets de la diminution de la resistance mecanique. Enfin, on presente les resultats de l'identification effectuee pour l'etalonnage des parametres caracteristiques des lois analytiques qui reglent le modele constitutif. (A).
The design analysis of a reinforced concrete building, seismically isolated at its base by a comb... more The design analysis of a reinforced concrete building, seismically isolated at its base by a combined system of steel-teflon sliding bearings and silicone-fluid viscous spring-dampers, is reported in this paper. The influence of the friction-like be-haviour of sliders on the global system response is initially examined, by exploiting the results of an experimental programme carried out to this aim within the European Community funded Research Project \u201cDISPASS\u201d. The application of a prelimi-nary design criterion, formulated in previous studies dedicated to this special protection strategy, is then presented. The damping coefficient of fluid viscous dissipaters capable of optimising the seismic response is particularly located by this cri-terion. A synthesis of the analyses developed by the finite element model of the structure is after-wards proposed. The performances obtained for the seismic action levels corresponding to the damage and ultimate limit states, according to the most recent Italian Standards (Ordinanza 3274) requirements, as well as to a third \u2013 so called maximum considered \u2013 earthquake level, are finally discussed
Selected topics from structural studies carried out on the damped cable system are presented here... more Selected topics from structural studies carried out on the damped cable system are presented herein. This seismic protection technique has been the subject of a European Community-funded Research Project, recently completed, where it was detailed, implemented, and assessed from analytical/numerical, experimental, architectural, and economic viewpoints. This allowed establishing the required scientific and technological basis for bringing the system to an industrial level. After a general framing of the system characteristics, this paper offers a demonstration of the on-site experimental section of the Project, developed on a full-scale mock-up retrofitted by damped cables. An example design of the system follows, with regards to the seismic rehabilitation of a medium-rise steel office building, representative of one of its preferential fields of application. Attainment of the enhanced performance objectives assumed in this design highlights the potentialities of damped cables as an advanced seismic-control strategy for framed structures
A school building with reinforced concrete structure, seismically retrofitted in 2013 and damaged... more A school building with reinforced concrete structure, seismically retrofitted in 2013 and damaged by the 2016 Central Italy earthquake, is examined in this paper. A time-history assessment analysis is initially carried out in pre-rehabilitated conditions by simulating also the presence of the clay brick masonry infill perimeter walls and partitions in the finite element model of the structure. Based on the results of this analysis, a different retrofit solution is proposed, consisting in the incorporation of dissipative braces equipped with pressurized fluid viscous dampers. The verification analyses developed in this new configuration for the main shock records of the 2016 earthquake highlight slightly damaged and easily repairable response conditions of a little number of partitions — instead of the diffused moderate-to-severe damage surveyed in the building internal and perimeter infills— and an elastic response of structural members.
A base isolation study on the advanced seismic retrofit of a reinforced concrete elevated water s... more A base isolation study on the advanced seismic retrofit of a reinforced concrete elevated water storage tank with shaft staging is presented in this paper. The tank was built in the late 1920s and is still in service. In consideration of its historical significance, base isolation offers an optimal joined solution to the concurrent issues of a substantial seismic performance improvement and a virtually null architectural impact on the superstructure. The isolation system is constituted by a set of double curved sliding surface isolators placed below the cylindrical shaft staging wall. The incorporation of the protective system causes to modify the pressurized pipes delivering water to the tank and the discharge pipes too. Two different interventions are designed to this aim. The first one consists in installing an expansion joint with high lateral displacement capacity at the connection of the mobile (i.e. linked to the superstructure) and fixed (i.e. linked to the pump lying on the...
A monolateral-friction element is specifically developed for modeling masonry structures. Its use... more A monolateral-friction element is specifically developed for modeling masonry structures. Its use in modeling masonry material and masonry structures is shown. In particular, the paper presents the proposed modeling technique together with some applications. The numerical results of the applications are compared to experimental results
The Open Construction and Building Technology Journal, 2019
Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out... more Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out with a conventional ductility-based approach. This implies a remarkable plastic demand on columns, as well as damages to the connections of structural and non-structural members, for seismic events with comparable intensity to the basic design earthquake normative level.Objective:In view of this, a study was developed and aimed at extending to the field of new prefab reinforced concrete structures the application of advanced seismic protection strategies, capable of guaranteeing undamaged response up to the maximum considered earthquake normative level.Method:A benchmark building was designed as demonstrative case study for this purpose, in the three following hypotheses: (a) according to a traditional ductility-based approach; (b) by incorporating dissipative bracings, equipped with fluid viscous dampers; (c) by placing a seismic isolation system at the base, composed of a set of doubl...
MATERIALS AND STRUCTURES/MATERIAUX ET CONSTRUCTIONS, Aug 1, 1996
Dans cet article, on presente les resultats d'un certain nombre d'essais a long terme (en... more Dans cet article, on presente les resultats d'un certain nombre d'essais a long terme (en traction simple et en flexion) effectues sur quatre sortes de pierres naturelles utilisees tres souvent autrefois en Italie pour la construction (le marbre blanc de Carrara, deux sortes de gres, la pierre de Florence et la "Pietraforte", ainsi que sur la pierre calcaire de Piobbico-Cesana). Les essais ont ete realises en appliquant de facon continue aux eprouvettes differentes fractions de charges "instantanees" de rupture, en relevant l'evolution de la deformation jusqu'a la rupture. En general, tous les essais ont montre un comportement caracterise par les trois phases classiques du fluage. En meme temps, on a constate une diminution de 60 % de la resistance, tant a la traction qu'a la flexion, par rapport a une duree d'essais peu superieure a un an. Cet article presente un modele constitutif phenomenologique permettant d'analyser le comportement visco-plastique observe. On indique ici, en vue d'applications techniques, une fonction de fluage qui permet l'evaluation directe des effets de la diminution de la resistance mecanique. Enfin, on presente les resultats de l'identification effectuee pour l'etalonnage des parametres caracteristiques des lois analytiques qui reglent le modele constitutif. (A).
The design analysis of a reinforced concrete building, seismically isolated at its base by a comb... more The design analysis of a reinforced concrete building, seismically isolated at its base by a combined system of steel-teflon sliding bearings and silicone-fluid viscous spring-dampers, is reported in this paper. The influence of the friction-like be-haviour of sliders on the global system response is initially examined, by exploiting the results of an experimental programme carried out to this aim within the European Community funded Research Project \u201cDISPASS\u201d. The application of a prelimi-nary design criterion, formulated in previous studies dedicated to this special protection strategy, is then presented. The damping coefficient of fluid viscous dissipaters capable of optimising the seismic response is particularly located by this cri-terion. A synthesis of the analyses developed by the finite element model of the structure is after-wards proposed. The performances obtained for the seismic action levels corresponding to the damage and ultimate limit states, according to the most recent Italian Standards (Ordinanza 3274) requirements, as well as to a third \u2013 so called maximum considered \u2013 earthquake level, are finally discussed
Selected topics from structural studies carried out on the damped cable system are presented here... more Selected topics from structural studies carried out on the damped cable system are presented herein. This seismic protection technique has been the subject of a European Community-funded Research Project, recently completed, where it was detailed, implemented, and assessed from analytical/numerical, experimental, architectural, and economic viewpoints. This allowed establishing the required scientific and technological basis for bringing the system to an industrial level. After a general framing of the system characteristics, this paper offers a demonstration of the on-site experimental section of the Project, developed on a full-scale mock-up retrofitted by damped cables. An example design of the system follows, with regards to the seismic rehabilitation of a medium-rise steel office building, representative of one of its preferential fields of application. Attainment of the enhanced performance objectives assumed in this design highlights the potentialities of damped cables as an advanced seismic-control strategy for framed structures
A school building with reinforced concrete structure, seismically retrofitted in 2013 and damaged... more A school building with reinforced concrete structure, seismically retrofitted in 2013 and damaged by the 2016 Central Italy earthquake, is examined in this paper. A time-history assessment analysis is initially carried out in pre-rehabilitated conditions by simulating also the presence of the clay brick masonry infill perimeter walls and partitions in the finite element model of the structure. Based on the results of this analysis, a different retrofit solution is proposed, consisting in the incorporation of dissipative braces equipped with pressurized fluid viscous dampers. The verification analyses developed in this new configuration for the main shock records of the 2016 earthquake highlight slightly damaged and easily repairable response conditions of a little number of partitions — instead of the diffused moderate-to-severe damage surveyed in the building internal and perimeter infills— and an elastic response of structural members.
A base isolation study on the advanced seismic retrofit of a reinforced concrete elevated water s... more A base isolation study on the advanced seismic retrofit of a reinforced concrete elevated water storage tank with shaft staging is presented in this paper. The tank was built in the late 1920s and is still in service. In consideration of its historical significance, base isolation offers an optimal joined solution to the concurrent issues of a substantial seismic performance improvement and a virtually null architectural impact on the superstructure. The isolation system is constituted by a set of double curved sliding surface isolators placed below the cylindrical shaft staging wall. The incorporation of the protective system causes to modify the pressurized pipes delivering water to the tank and the discharge pipes too. Two different interventions are designed to this aim. The first one consists in installing an expansion joint with high lateral displacement capacity at the connection of the mobile (i.e. linked to the superstructure) and fixed (i.e. linked to the pump lying on the...
A monolateral-friction element is specifically developed for modeling masonry structures. Its use... more A monolateral-friction element is specifically developed for modeling masonry structures. Its use in modeling masonry material and masonry structures is shown. In particular, the paper presents the proposed modeling technique together with some applications. The numerical results of the applications are compared to experimental results
The Open Construction and Building Technology Journal, 2019
Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out... more Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out with a conventional ductility-based approach. This implies a remarkable plastic demand on columns, as well as damages to the connections of structural and non-structural members, for seismic events with comparable intensity to the basic design earthquake normative level.Objective:In view of this, a study was developed and aimed at extending to the field of new prefab reinforced concrete structures the application of advanced seismic protection strategies, capable of guaranteeing undamaged response up to the maximum considered earthquake normative level.Method:A benchmark building was designed as demonstrative case study for this purpose, in the three following hypotheses: (a) according to a traditional ductility-based approach; (b) by incorporating dissipative bracings, equipped with fluid viscous dampers; (c) by placing a seismic isolation system at the base, composed of a set of doubl...
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