SAN NICCOLO’S TOWER-GATE, FLORENCE – ITALY: MASONRY CHARCTERISATION AND STRUCTURAL ANALYSIS

This San Niccolò’s tower-gate stands up for 40 m on the Southern bank of the Arno River at Florence (Italy) as witness of the III Medieval ring of the city-wall erected in the XIV century. The Florence Municipality, for conservation purposes, planned to acquire knowledges on the Tower-Gate structure and masonry to leave hand down and perform seismic vulnerability assessment for that outstanding historical monumental building. The studies had been developed in three stages: 1) geometric survey by means of laser scanner and photogrammetry by drone and ground, with HBIM implementation. 2) NDT and LDT investigations performed according to the rule in force, namely the “MIBACT 2011 Guide Lines” for historical buildings. 3) seismic parametrization of the ground and tower-gate’s masonry, and analysis of the seismic vulnerability of the tower-gate. The geological background implies that the tower’s foundations are a few meters deep and rooted in hard quartz-calcareous turbidites bedrock. The seismic survey and the microseismic zoning of the Florentine area led to define the seismic parameters for the ground and the Towe-Gate. We conclude that the state of conservation of the Tower-Gate satisfies the principle of Integrity and Authenticity and the seismic performances are verified.