1. Cavaleri, C. Cucchiara, A.Tommaselli, G. Zingone


Maintenance of the historical monumental heritage has produced the increasing of interest in masonry structure mechanics and in research of new strengthening techniques. As a matter of fact historical structures (most of them are masonry structures) perform often a low capacity with respect to exceptional loads or a reduction of the capacity with respect to service loads because of aging. So that improving and retrofitting devices must be adopted.

Vault is a structural elements that often can be found in historical building with need of reinforcement. It is generally subjected to vertical loads that, in spite of its structural shape, can produce tensile stresses on it with a reduction of the safety level. As a consequence of vertical loads vault produces thrusting forces on walls that sum to the horizontal forces produced during the seismic events.

These factors increase the collapse probability of the walls under seismic actions, especially when the material is damaged because of aging, so a reduction of the produced thrust is desirable. On the other hand, as it often happens, the change of the service loads because of the variation of using destination (for example from residence to public) may request the reinforcement.

In this paper the devices used for the strengthening and improving of a vault of an ancient aristocratic house of Palermo, Villa Cattolica, are described. The interventions have basically the goal of improving the resistance under vertical and horizontal loading.

Through the paper is underlined the need of no change the look of the construction in order to not modify its real artistic value so, generally, only special kind of strengthening devices can be used.

In order to verify the effectiveness of the improvements, dynamic and static tests have been performed before and after the interventions. The results of static tests are mainly showed and the modifications in the structural behavior are described.

The structural analysis has been performed for the behavior prediction. Two different stages have been taken into account: the uncracked and the cracked one.

The strengthening system, made by applying CFRP strips on the upper surface of the vault, is presented through the paper.

Key words: masonry structure, vault, fiber reinforced polymer, retrofitting.