Renzo Piano’s bridge is much more than just a bridge

The Genoa–San Giorgio Bridge, that stands where Ponte Morandi used to be, is more than a viaduct, it is an idea for the development of the city.

It will be a simple, frugal bridge, but not ordinary. A sober bridge in keeping with the nature of the Genovese.” What Renzo Piano had in mind right from the start, in the tumultuous and dramatic hours following the tragic collapse of the Morandi Bridge, was an anthropological approach to architecture. Twenty-two months later, we have the Genoa-San Giorgio Bridge. Going beyond the justifiably proud talk of work finished in record time, the healing of a wound in connective tissue that is both urban and human, nearly one year after the inauguration, now stands as a symbol for rebirth. The architecture, engineering and unquestionably also the landscaping of Piano’s bridge, engineered by Italferr and built by the PerGenova consortium (Webuild and Fincantieri Infrastructure), is now a visual fixture in a fragile and highly anthropized part of the city in Val Polcevera. The road connections to the new bridge and the new western on-ramp respond to the need to reconnect the existing road infrastructure: the Coronata tunnel to the west and the A7 interchange to the east. 

The “luminous trail” of the bridge at night (lighting by iGuzzini). During the day, it eflects sunlight and absorbs solar energy, and at night, it returns it.

The work re-establishes a fundamental road and transportation link in Genoa, Liguria, and whole north-western Italy. In a larger sense, it is a catalyst for rethinking and harmonizing not only two halves of the city, but also the hills and the coastline, as well as the urban, extra-urban, and harbour road network, with approximately five thousand vehicles in and out of the port every day. It responds to the needs of a city built against a slope and down to the sea, not merely a physical response but also a projection of its destiny, of Genoa’s millenary vocation to embrace the world, one that must continue to guide its development. 

Detail of the deck-pier joint, which allows the bridge to “breathe” without compromising strength or stability.

The designers responded to this structural and metaphorical need with the concept of an “urban bridge”, as Piano characterizes it, that not only fulfils infrastructure functions but also finds its place in the surrounding context, prompting dialogue between sight, light, and the sweep of the sea. “There are two ways to get to Genoa,” writes Piano, “one via the Turchino pass, when the sea comes into view after the last tunnels, or crossing the Polcevera valley, when you begin to behold the light of Genoa, as we once did crossing the Morandi bridge. Because Genoa has a particularity: the sea is to the south, the sunlight reflects off the water and onto the city. And this gives the city the special qualities of its light. And so we spent a lot of time working on the lateral barriers. With its transparent sides and lack of superstructure, the bridge affords uncluttered views up the valley and out to sea.” 

The urban setting for the viaduct over the Polcevera valley harmoniously connecting two parts of the city of Genoa.

Visual criteria thus dictate the structural specifics. The elliptical-section reinforced concrete piers, free of sharp corners, allow sunlight to slip over the surface, mitigating the visual impact of the infrastructure and its presence in the urban fabric. The shape of the deck recalls a ship’s hull floating above the piers on support devices that allow the viaduct to breathe without compromising stability or strength. The system is structurally optimum, limiting the dimensions and thus the impact of the substructures, and most importantly the foundations, in this densely urbanized context. 

Renzo Piano and collaborator Stefano Russo with one of the first project drawings.

But the San Giorgio bridge is also a highly advanced technological machine: a complex system of internal sensors—accelerometers, strain gauges, speed monitors, inclinometers, and joint expansion and differential displacement sensors—provide a constant flow of data on the behaviour of every part of the structure, creating a readily accessible database that will be of great value in designing similar infrastructure in the future. The form of the deck is architecturally significant. The progressive reduction in section toward the edges further attenuates the visual impact. The light coloured paint on the steel adds luminosity and better integrates the viaduct into the landscape. In short, it is a fully aesthetic work that both serves a function and points the way beyond.

Connected to the world
by Marco Bucci, mayor of Genoa.

Renzo Piano’s project reflects the new Genoa, with architectural, urban, and strategic projects underway oriented to global business. While investments by state agencies have been guided by a vision of the self-enclosed city over the past thirty years, leading to the current infrastructure deficit, now we commit to opening to the world as in the days of the Republic of Genoa. And so we want, first of all, for the harbour to live in the city and the city to be alive at its harbour. The waterfront regeneration project, now in the executive phase, regards transforming from port facilities to fully developed urban functions, creating a “city harbour park” that will shift the city’s centre of mass towards the sea. This will benefit the adjacent historical centre, currently the object of another regeneration project (“Caruggi” – alleys). In the future park under the Genoa-San Giorgio Bridge, Stefano Boeri Architetti envisioned the Red Circle, a steel ring connecting a territory of iron, water, cement, and asphalt under and around the viaduct. This element symbolizes the new bond between the two sides of the valley and the creation of hitherto impossible connections that will greatly expand the range of pedestrians and bicyclists.

We gave ourselves a strict timeline and a methodology that soon led to the inauguration of the Genoa-San Giorgio Bridge, a new benchmark work method for Italy and a symbol of the city’s forward thrust.

International overtures demand international infrastructure, both physical and digital. New undersea cables crossing the Mediterranean will bring close to 500 terabits of data per second to Genoa: the world’s highest digital volume will flow into and through our city. Work has begun to modernize and expand the Cristoforo Colombo Airport passenger terminal. By 2025 we will totally eliminate carbon fuels from our local public transport system and will have the first fully eco-sustainable port in Europe: all energy, powering both watercraft and shoreside facilities, will be blue or green. To remake Genoa, we must think globally and act locally. And that is precisely what we did to rebuild the Polcevera viaduct. When Prime Minister Conte offered me the position of Special Commissioner for the New Bridge in October 2018, I accepted without reservation. As mayor, I could not possibly refuse this responsibility. I dove right in. We gave ourselves a strict timeline and a methodology that soon led to the inauguration of the Genoa-San Giorgio Bridge, a new benchmark work method for Italy and a symbol of the city’s forward thrust. 

The Genoa–San Giorgio Bridge is made of steel and reinforced concrete. It is 1,067 m long, 30.8 m wide, and stands at 56 m a.s.l.
The bridge rests on 18 piers (4 x 9.5 m elliptical section) with a constant pitch of 50 metres, except for the three central spans that, crossing the Polcevera stream and the railway areas, have a pitch of 100 metres.
The reinforced concrete and steel viaduct has a curved section with maximum thickness of 4.80 m at the midline. The steel part of each span is composed of three 26-metre-wide segments made of different thicknesses of plate steel.
Opening image :
the beauty of the structure is its lightnes

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