La riforma dei ‘gugliotti’ del tiburio del Duomo di Milano. Dal progetto di ricostruzione alla conservazione integrata

The completion of the Milan Cathedral, with the realization of the last gugliotti, the four towers with internal stairs displaced around the tiburio, was characterized by an intense discussion forcing Giuseppe Vandoni to a critic evaluation of the work carried out by his predecessors until the 19th century. The gugliotti built by Amadeo and Pestagalli were considered two reference models for the design of the last two towers. If the tower designed by Amadeo was seen as the prototype for the style, with the high quality of its decorative sculptures, the one realized by Pietro Pestagalli, higher than the first one and directly connected to the top of the dome, was considered as the best practice solution for connecting the lower with the higher level of the terraces constituting the roofing system of the Cathedral. The contents in the discussion exchanged between architect Vandoni and the academic commission of architecture show the development of a debate still influenced by an open question on the proportion and the style of the Cathedral. The solutions adopted in this period, until the realization of the last tower by Paolo Cesa Bianchi, determine important impacts on the relevant structural interventions carried out by Carlo Ferrari da Passano during the 20th century. These recurrent discussions denote the hard balance among the reasons of the aesthetics and the ones of the practice, putting at risk the preservation.