ABSTRACT
Collapse of timber roof structures covering ancient churches often occurs during earthquakes. Frequently, the roof engages in the collapse also the underlying masonry structure, producing extensive damage. Several roof failures were observed in Italian earthquakes, in the L 'Aquila earthquake of 2009 and in the Emilia region in 2012. The roof structures had mostly a geometrically simple layout, being conceived as a series of parallel trusses covering the nave. The analysis of limit equilibrium for heritage artifacts and for traditional masonry buildings in general is now required by the Italian building code and by Guidelines for seismic safety of heritage buildings developed by the Ministry of Cultural Heritage, MiBACT. Many damage mechanisms in the proposed set develop from the interaction of the masonry with the roof structure, or are fostered by it. A deformable roof structure, with a ridge beam pounding on the tympanum has been recognized in many instances as a possible cause or a contributing factor.
