The “Cisternone” (It: big tank) is the most noticeable element of the acqueduct build by Grand Duke Ferdinando I in 1588 to provide Pisa with fresh water. To facilitate the visiting, a glass floor was placed to cover the tank, supported by a steel structure consisting of a series of portals joined together by secondary beams. The main beams have a welded composite T-section with variable height; the secondary beams have the same section, with smaller dimensions, whereas the columns are CHS.
The framework is statically insulated at the sides of the tank, so that is has a response to vertical loads and seismic actions which is completely independent from the tank itself. The glass panels of the new floor level are made of layered panes of 8+10+8 mm thickness with PVB interlayer.