Following the seismic disaster of September 1997, few buildings were seriously damaged constituting a clear danger for public viability. To prevent from this, Regione Umbria has designed a series of prevention plans in order to restore safety conditions, with two main guides:
– The demolition of unsafe buildings (more invasive) and the management of provisional works to secure architectural and artistic relevant buildings likely to collapse. These provisional works were characterized by rapidity of execution, as well as the possibility of removing provisional work for the final restoration.
For some types of instability, double shell carbon bands -30 cm high- were used in order to discard collapse possibility of unsafe parts. The use of FRP materials is excellent when buildings, subject to the pushing action of covers, were about to collapse. The disposition of sleeves allows balancing the push of the covering structures, redistributing the strength along the main walls.
Those mentioned options and the materials used permitted: first, the rapidity of action that allowed solving immediately a hazard condition and second, but not less important, the fact that these interventions were permanent, which means only advantages for the building property and represents no contraindications as the aesthetic and architectural aspects are concerned.
The definitive allocation under the plaster will permit the removal of traces of the works performed. The ability of working outside is a great advantage because there is no need of accessing the interior of damaged buildings; another advantage is the bands adaptability to irregular shape profiles, overcoming obstacles as gutter channels, electrical wires…etc.
This technology avoids the risk of overturning collapse of slender elements of the structure, as for example chimneys or belfries, very unstable in seismic incidents.
The final covering with quartz sand protects from ultraviolet action. Please note that this intervention does not request any maintenance or stringing seasonal phases, as it is in the case of external metal cables sensitive to the variation of temperature. SRG products constitute strong innovation in the market and increase the potential of an intervention with composites.
SRG composites, with difference from the FRP, allow a pretension operation of the bandage through a tightening device. This active operation option increases level of security in the intervention area. The active thrust allows a resistant strengthening at a first step with no need of further actions against deformation.