Reading of the compositional geometries for the knowledge of the architectural work. The integrated survey of the bell tower of the Pietrasanta Cathedral.

The exterior of the bell tower of Pietrasanta is in bricks but the irons on the façade suggest that the marble cladding similar to that of the cathedral was envisaged. In the inner part a singular spiral staircase, carved in the wall section, ascend in a helical path and it’s wraps around the ideal axis of the bell tower. So this spiral generates an eye that behaves like the stem of a column, represented here by the void: a grandiose sculpture in negative to volume coclide. A Renaissance architecture (1519) of the highest value; an invention in which the extraordinary geometrical complexity that accompanies a brilliant technological-constructive wisdom makes Michelangelo Buonarroti hypothesize as its architect, given also the congruity of this architecture with its sculptural principles, as well as its presence on site in those years. The research has dealt with the integrated survey of the tower bell with the aim of research its precise geometries, analysing it since from the construction site thanks also to the measurement system used. The agreement with the Curia of Lucca was stipulated for the three-dimensional survey as a control carried out for the purpose of restoration that the bell tower must undergo.