The Challenge of a Designer and His Confidence in Masonry: The Case of a 19th Century Italian High Dome

The paper tells the story of the designer Alessandro Antonelli and of his determination (1798-1888) to create a majestic construction above the cross vault of St. Gaudenzio Basilica built in 16th century in Novara, Italy: a 121 m (397 ft) high dome made entirely in masonry. Construction of the dome began in 1844, and as it progressed, it was interrupted several times and the project continued to evolve, increasing more and more in height, until it reached its current configuration in 1878, which features 5 domes stacked on top of each other. In the following years the church began to show signs of structural failure, and Antonelli worked on the old foundations and pillars, which he judged to have been made of poor materials, because he firmly believed in the correctness of his design. Because of its size, the population often feared a possible collapse of the dome, until small signs at the top, observed in 1930 under the gilded, hollow statue placed at the summit, gave rise to a series of interventions to replace stone and masonry elements with concrete ones. These interventions, carried out by a distinguished professor of the Politecnico di Milano (Eng. Arturo Danusso), reassured the citizens, but at the same time, they turned out to be responsible for a series of chain reactions that required continuous subsequent modern interventions on the masonry dome. In the early 21st century the last interventions were carried on: they were certainly very cutting-edge when implemented, but they unfortunately proved to be based on a lack of real understanding of the masonry structure. It is intended here to retrace the history and the current description of this daring masonry construction, more interesting when seen from the inside than from outside, still little investigated, but which became the symbol of a city and the determination of its designer.