Recent Italian seismic events, as L’Aquila earthquake (2009) and Emilia earthquake (2012), demonstrated the deficiency of the actual design approach of the cladding panels system in precast buildings. Collapse of these precast panels is observed due to the connection system failure. Although cladding panels are designed as non-structural elements according to the actual code approach, i.e. no interaction with the structure is considered, a seismic excitations could make the panels collaborating with the resistant system. In this paper the influence of vertical cladding panels on seismic behavior of one-story precast concrete buildings is investigated. A parametric study is carried out to judge the influence of the cladding presence on the dynamic characteristics of precast structures. At this purpose, modal analyses are performed on both bare and infilled models. The parametric study shows a high influence of the panels on the first period of the structure, as well as the inadequacy of the code relationships for the evaluation of the natural period for such typology of structure. More suitable relations are proposed in order to evaluate the seismic demand of one story precast buildings both in the case of bare and infilled system.
Precast structures have a very large diffusion and for some types of buildings represent a considerable estate. However, latest earthquakes, as L’Aquila earthquake (2009) and Emilia earthquake (2012), have pointed out some lacks in the design approach for the precast buildings, among which the inadequacy of the panel–to-structure connection systems. Indeed, most of the numerous damaged precast buildings showed the collapse of cladding panels, caused by the connection systems failure (, , ).According to the actual code design approach, precast structures are usually considered as bare systems and the cladding panels are separately designed for actions deriving by itself weight and seismic or wind loadings; no interaction between panels and structure is then considered. However, during a seismic event, the panel-to-structure connections could make the panels collaborating with the structural system, increasing the structural stiffness and, hence, the seismic demand on the devices. Moreover, the failure of the cladding panels cannot be considered as the exceeding of the serviceability limit state but, to all intents and purposes, it must be considered as an indicator of ultimate limit state reaching, given its impact on the life human safety.
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This article is part of "Opensees Days Italy" - Modeling, Design and Analysis of Structures in Seismic Areas. Proceedings of the 1st Italian conference - Rome, 24-25 May 2012
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Il presente articolo è tratto dagli atti di "OpenSees Days Italia" - La modellazione, il calcolo e l’analisi delle strutture in zona sismica.
Atti del 1° convegno italiano – Roma, 24-25 maggio 2012
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Il volume può essere richiesto scrivendo a Massimo Grasso - firstname.lastname@example.org