A comparative analysis of masonry chimneys: typical damages and preservation strategies

During the industrial revolution, the diffusion of furnaces for different productive activities implied a spread use of masonry chimneys for disposal of the emitted combustion smoke. Their presence became a symbol of the manufactory growth in Western countries and contributed to characterize the skyline of areas, as the churches bell towers in the past. A large number of these structures are now listed as protected buildings by the Italian Ministry of Cultural Heritage, and this implies that they have to be repaired and maintained in a good and safe state of conservation, also when the factories in which are inserted are completely disused or demolished. In the paper, a series of recurrent damages observed on different disused Italian chimneys is reported, particularly in Lombardy region. Some general remarks will be given, based on the experience made on some masonry chimney in Northern Italy, with the aim to define a correct preliminary approach to the structural analysis and to their conservation.