On August 14, 2018, the 1967 cable-stayed Morandi Bridge partially collapsed over the Polcevera River and valley in Genoa, Italy, tragically killing 43 people. Neglected structural faults in the prestressed concrete that surrounded its stays were deemed the cause of its failure during a heavy rainstorm. The bridge was an integral connector in the flow of intercity, regional, and international traffic, and its collapse raised questions about the state of infrastructure in Italy; city officials were keen to replace it. The search for a new architect did not take long: They turned to Genoa’s local starchitect Renzo Piano for a safe technologically advanced design that would help to transform the area. This month, two years after the tragedy, the new San Giorgio viaduct was completed.
Piano designed the bridge to look like the curved hull of a ship when viewed from beneath.
“The new bridge must be simple and straightforward but not ordinary,” says Piano of his design. “It is a moderate bridge, respecting the character of the Genoese.” Though it may be moderate in aesthetics, the viaduct is emphatic on engineering and uses support devices to seemingly float the bridge over its 18 structural piers, a structural method that allows for seismic stability while decreasing the size of the piers themselves. Steel ribs at the end of the deck help provide further support. For constant assurance that the bridge is functioning properly, a system of sensors (accelerometers, extensometers, velocimeters, inclinometers, and detectors) track for joint expansion and differential displacements. Cleaning and maintenance robots will survey the structure, its systems, and a glass barrier along its pedestrian edges. Photovoltaic panels spanning its length power these sensors and systems.
The original bridge was demolished in August 2019, and construction on the new San Giorgio bridge began soon after.
Integrating these technologies. Piano created a bridge that “looks like a ship moored in the valley; a bright, clear steel bridge.” From underneath, the structure alludes to the curved hull of a ship. Though in profile, the intention for it was to appear as unobtrusive as possible, an urban bridge that is in tune not only with existing infrastructure but also with the surrounding area. Its elliptical “hull” has no sharp corners, mitigating its visual impact and reflections. Explains the architect: “During the day, it will reflect sunlight and absorb solar energy, and at night it will return it.” With time, it is hoped that the bridge will be power self-sufficient and that its advanced technological achievements will make the new bridge a model for future infrastructure projects.
Renzo Piano (82) won the Pritzker Prize in 1998.
The Morandi bridge was demolished in August 2019, and construction on the San Giorgio bridge began soon after. Completed in only a year, it has one of the fastest construction timelines seen recently in Italy, even despite the country’s severe battle with COVID-19 at the beginning of 2020 and the usual red tape that causes delays. (In the southern state of Calabria, for example, the Cosenza bridge by Spanish architect Santiago Calatrava took over 20 years to finish.)
For constant assurance that the bridge is functioning properly, Piano’s team implemented a system of sensors track for joint expansion and differential displacements.
“It’s a miracle … but it’s not,” said Piano recently to BBC. “If pride and knowledge get through complexity and bureaucracy, it’s possible. Italy is able to do these kinds of things. But I don’t understand why this simply becomes possible when you have a tragedy.” For those whose loved ones were lost in that tragedy, justice is being served at a much slower pace. Beneath the new bridge is a memorial park with the names of the 43 people who died in the collapse and 43 trees to represent them; the youngest victim was eight years old.
