Wind design of steel-framed buildings aims to provide appropriate stiffness and strength properties of the structural elements, so as to obtain an elastic behaviour, at the same time as controlling floor displacements and accelerations. On the other hand, in a seismic design it is commonly accepted that the structural members can undergo inelastic deformations under strong ground motions, provided that these deformations be kept within an acceptable threshold; moreover, deformability thresholds are also imposed at the serviceability limit state. Nevertheless, knowledge on the wind and seismic responses in the case of fire is lacking and an amplification of the structural response is expected in the case of existing structures exposed to fire. To evaluate the wind and seismic responses following a fire, a numerical investigation is carried out with reference to the steel framed structure of a ten-storey office building, which was designed for a low-risk zone under the former Italian seismic code and in line with Eurocodes 1 and 3. More specifically, the dynamic response of the test structure in a no fire situation, along the in-plan principal directions, is compared with what would happen in the event of fire, at 500°C, 550°C and 600°C fire temperatures, hypothesizing a reduction of stiffness and strength due to fire. Four fire scenarios have been considered on the assumption that the fire compartment is confined to the area of the first level (i.e. F1), the first two (i.e. F1/2) and the upper (i.e. Fi, i=5, 10) levels, with the parametric temperature-time fire curve evaluated in accordance with Eurocode 1. Dynamic analyses are carried out in the time domain using a step-by-step initial stress-like iterative procedure. Along-wind loads are considered assuming, at each level, time histories of the wind velocity for two return periods (i.e. Tr=10 or 50 years), based on an equivalent spectrum technique. Real accelerograms, whose response spectra match those adopted by Italian seismic code for a mediumrisk seismic zone and a medium subsoil class, are considered to simulate the seismic loads.
PurposeThe purpose of this paper is to show the importance of a total understanding of the manufacture, before approaching any structural intervention.Design/methodology/approachThe adopted methodology consists of a non‐invasive kind of structural retrofit, in accordance with the history of the manufacture and, at the same time, giving effective respect to seismic solicitations.FindingsThe results are very important for demonstration purposes, and they may be taken as examples in many similar problems.Research limitations/implicationsThe limitation of this research principally consists in the old datation of the study case, because it could be approached more easily with the help of modern concepts.Practical implicationsMany applications can be carried out from the study case: first, the respectful approach to the cultural heritage, in the sense of knowledge and understanding of the “art rule” belonging to the ancient constructors.Social implicationsThe paper has implications for the safety and conservation of historical heritage.Originality/valueThe originality consists in showing the almost unknown work of a master: he reasoned anticipating the technological progress.
Existing masonry buildings are often the result of constructions, changes and alterations that have developed over the centuries. Therefore, the adaptation and improvement of existing masonry buildings must be accompanied by an adequate level of knowledge of their history. The tragic consequences of the recent earthquakes, in Italy and abroad, have stimulated the belief that, sometimes, the cause of seismic damage might be just the wrong intervention of improvement or adaptation. In most cases, this is attributable to retrofit works which are carried out without any knowledge concerning the construction rules of the building. The case study presented here regards the seismic analysis of the Sant' Agostino Church in L'Aquila (seriously damaged by the earthquake occurred in April 2009), which takes into account the in-depth knowledge of the factory, respecting all three evaluation levels of seismic safety provided by the Italian seismic Guidelines for Cultural Heritage (
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