Restoration and Repair of the St. Nicola Church in Pisa

The paper deals with the restoration and repair of the façades of the St. Nicola Church in Pisa. The St. Nicola Church is one of the most important churches in Pisa. The construction of the Pisan Romanesque style church and of the adjacent monastery dates back to the 11th century; in the period 1297–1313 Augustinian fathers promoted significant enlargements sometime attributed to Giovanni Pisano and finally at the beginning of the 17th century it assumed the actual internal configuration. The main façade is characterized by a marble cladding in the inferior part and by exposed brick masonry in the upper part. During the years a significant crack pattern appeared on the upper part of the façade: despite in the past repair attempts were made with different techniques, as evident studying the texture of the façade itself, the propagation and reopening of the cracks were not effectively prevented. The pathology of the façades is critically discussed and the repair solutions implemented in the restoration phase are illustrated, with particular emphasis on an innovative use of FRP (Carbon fiber) fabrics, which has been inserted in the horizontal mortar layers between adjacent brick rows of the exposed masonry to close and to bridge the cracks. Although risky from aesthetic point of view, this innovative technique was positively implemented. Moreover, since after some years from the intervention cracks are still closed, it can be concluded that the proposed technique is also very effective.