RE 5 Report on "Restoration Strategy". December 2004 pp. 1-27

The damage exhibited by the building, although serious, is compatible with that predicted for buildings with similar characteristics and is justified by the onset of relatively clear-cut kinematisms. This certainly facilitates the definition of the structural action required to ensure security and overall consolidation, which nevertheless represents a rather difficult task. The observed structural damage is related to obvious structural shortcomings affecting above all: a) the low resistance of the walls vis-a?-vis the actions taking place out of the plane and causing the overturning mechanisms; b) the absence of any links among structural elements capable of absorbing tension stresses; c) the presence of unopposed thrusts. The latter aspect takes on greater significance owing to the serious consequences that it produces also under static conditions. Consideration must be given also to the behaviour of the soil, which is highly stressed and followed the rotational movements of perimeter walls and the central pillars. The path to follow to recover the structure and to improve its antiseismic performance is indicated by the actual structural shortcomings observed; the intervention project must therefore take into account the weaknesses displayed by the building in order to pursue a better overall behaviour. In particular, measures must be taken to prevent the overturning of the walls at greater risk; control of these mechanisms is the priority objective, as in the current conditions the perimeter walls are in conditions of precarious equilibrium with respect to orthogonal earthquakes. Preventing the development of these kinematisms would mean exceeding the resistance threshold and allowing the structure to cope with a higher threshold represented by the rupture mechanisms in the plane, which are less probable and dangerous.