Steel against earthquake

F.M. Mazzolani
University of Naples "Federico II", Naples, Italy

ABSTRACT: The use of steelwork for seismic protection purposes is now-a-day a reliable

solution whose effectiveness is proved by the evidence of the catastrophic earthquakes in the World. This aspect is widely illustrated in this paper, considering different aspects, from the development of the design methodologies to the current codification, form the structural typologies to the damage analysis and consequent lessons. Some significant examples of seismic resistant buildings, erected in the European earthquake prone Countries during the last decades, are also illustrated.

1 INTRODUCTION

From the seismic point of view, Europe can be considered as subdivided into two main parts. The northern part is geologically stable and the southern part around the Mediterranean basin is generally earthquake prone with different intensities from one side to another.
The northern Countries use steel and composite structures more than the southern Countries mainly for economical reasons, but also for a more consolidated tradition. They design seismic resistant steel and composite structures just for exportation to the earthquake prone Countries of the third World.
Contrary, the southern Countries are less rich than the northern ones and they traditionally use both masonry and reinforced concrete as the most common constructional materials.
The lesson learned in the last decades from the more severe earthquakes in south Europe (Friuli – Italy, 1976; Bucarest – Romania, 1977; Campania and Basilicata – Italy, 1980; Banat – Romania, 1991; Erzincan – Turkey, 1992; Dinar – Turkey, 1995; Umbria – Italy, 1997; Adana – Turkey, 1998; Izmit and Duzce – Turkey, 1999; Athens – Greece, 1999) have shown that the behaviour of reinforced concrete structures, which are the majority there, has been generally very poor for many unquestionable reasons, i.e. non-seismically designed structures or formally seismically designed but characterised by wrong detailing and bad execution with poor materials or seismically designed but with load lower than the actual one. The collapse of r.c. buildings is very often a tragic reality in the Mediterranean Countries (Figure 1). On the contrary, the performance of steel and composite structures, even if they are not very numerous, has been satisfactorily good everywhere, with very limited number of damage and total absence of collapsed buildings.

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