Traffic effects on historical artefacts

The environmental impact of vibrations due to traffic is an extremely serious and pressing problem in residential areas. In particular, historical centres have a high concentration of historical heritage that need be protected by actions that can generate additional stress on the structures. A lot of work has been carried out with reference to the structural damage produced by traffic vibration, but very few contributions have been provided so far with reference to the damage in the historical artefacts. The problem is worthy to be investigated as many historical buildings are located close to important arterial roads and the value of such buildings is often given by the historical and artistic surface coatings (frescos, mosaics, plasters, stucco, etc.) rather than by the masonry structures that bear them. In the past a notable amount of work was carried out by the Road Research Laboratory. Watts [1] showed that the heavy vehicles produce most of the significant vibrations and that they are directly related to the type of surface roughness of the road. In [2] four buildings were analysed by monitoring the acceleration in the walls and at the floor levels. In [3] it is underlined that traffic vibrations are rarely responsible of structural damage but they may cause surface and non-structural damage. Such a issue becomes dominant for heritage buildings. Some studies were carried out in Italy. In [5] the amplitude of the accelerations induced by the traffic were monitored in a XIX century masonry building in Naples nearby a main road: the vibrations induced were associated to the type of vehicle and to its velocity. In the present paper a preliminary study of the traffic vibrations induced on valuable decorations (such as frescos, mosaics, plaster, stucco, etc.) in historical buildings is performed. Such vibrations may be meaningless for the structure but deleterious, and amplified by the cyclic nature, on decorative non-structural elements. Two historical Palaces in Ferrara are monitored, both located nearby important arterial roads.