Seismic adaptation of existing structures

Seismic Adaptation
The seismic event that frequently strikes the regions of central Italy raises, once again, the question of the inadequacy of a large part of the existing building stock to resist the telluric actions that periodically upset the national territory, each time causing death and destruction .

In this regard, the major experts in the field agree on the fact that the cost of preventive safety measures for existing buildings in Italy would be lower than the sum spent from 1968 (the year of the Belice Valley earthquake in Sicily) to today for the reconstruction of the earthquake-stricken areas.

The safety and/or construction of new buildings according to anti-seismic regulations would be the only way to reduce the devastating effects of future earthquakes that could affect Italy.

From an operational point of view, steel, as a ductile and light material, plays a fundamental role both in the construction phase from scratch and in the safety of existing buildings; as demonstrated by the widespread use of it in geographical areas subject to strong earthquakes, such as Japan and the United States.

As is well known, the efficiency of metal buildings in the face of seismic actions lies in the high ductility of steel which reaches levels of energy dissipation that are precluded by other construction materials; to this, we then add the characteristic of prefabrication and dry assembly which significantly reduces the weight, thus subjecting the structures to more limited seismic actions.

A more in-depth study of the parameters that define the seismic response of structures, increasingly supported by current legislation, has led to two different intervention strategies:

The first through seismic isolation – with the introduction of a system of flexible devices capable of reducing seismic actions between the foundation integral with the ground and the upper part of the building;

The second through seismic dissipation – with the introduction of particular devices (dissipative bracings) capable of dissipating the energy that hits the building, eliminating/reducing damage to the structures of the manufactured.

The ICOMET Costruzioni Metalliche S.r.l. boasts experience in the field of anti-seismic adaptation, having operated in a context such as Irpinia, strongly affected by the 1980 earthquake, where anti-seismic building practices can boast experimentation thirty years. Among the most important interventions we report, by way of example, the seismic adaptation obtained through hysteretic dissipative bracings (Brad type heat sinks), carried out at the San Tommaso school building in the municipality of Avellino.