The monumental complex of San Placido Calonerò, in the surroundings of Messina, on the eastern coast of Sicily, Italy, which was originally a Castle for the Vinciguerra family, became the location of the Benedictine Abbey of San Placido Calonerò in the XIV century. The religious edifice is centered upon two cloisters which characterise the Renaissance features layered upon the primitive medieval character. The structure remained substantially unaltered for centuries, until the Messina earthquake of 1908 when, following relevant damages, it underwent some important modifications, in particular the reduction in height of an entire story and the detaching of some of the monumental entrances. Unfortunately in the middle of 1990's an invasive structural retrofitting project modified the structure of the two cloisters, the modification of which are characterized by a sequence of crossed vaults built in vaulted brick masonry and which gently adjoin the Renaissance columns with Ionic capital. This system, which was well-performant for five hundred years, was altered by the insertion of a reinforced concrete layer bounded to the underlying brick masonry layer through transversal steel joints. From that time onwards the two cloisters are involved in a series of structural problems that come into sight through structural damage in the columns that are now subjected to heavier loading than they were previously. With the aim to look over the new equilibrium conditions of the cloisters and assess how to act to limit the damage evolution, the structural behavior of a typical cell of the cloister is simulated by means of a refined nonlinear finite element model in which the structural layout of the cell, before and after the inadequate retrofitting, are modelled.