GENOA, ITALY -- A final section of a new bridge in Genoa, built after a deadly 2018 motorway collapse, was to be slotted into place Tuesday, providing a much-needed symbol of renewal for coronavirus-hit Italy.

Construction of the gleaming structure in northern Italy's coastal Liguria region has continued night and day throughout a national lockdown as the country has battled a virus that has officially killed nearly 27,000 people.

Sirens will sound as the last vast section of deck is put in place and one side of the Polcevera valley is finally reconnected with the other, in a rare success story during Italy's worst crisis since the Second World War.

"Updates on the construction -- piece by piece, deck by deck, pillars and so on -- have become almost essential for many Italians," the Corriere della Sera wrote last Monday.

"They've allowed them to imagine a fresh start, allowed them to be proud."

Genoa's Morandi highway collapsed during heavy rain on August 14, 2018, hurling dozens of cars and several trucks onto railway tracks below and killing 43 people.

The bridge had been riddled with structural problems for decades, leading to expensive maintenance, and its collapse threw the spotlight on Italy's creaking infrastructure.

'How to go on'

Famed Italian architect Renzo Piano designed the replacement, giving it a curved, gleaming underbelly evoking the hull of a ship in tribute to Genoa's maritime history.

The hight-tech structure will have maintenance robots running along its length to spot weathering or erosion, as well as a special dehumidification system to limit corrosion.

"In building the bridge we've been up against time, against the elements, against bad weather, against all the difficulties we've faced," Pietro Salini, CEO of Italy’s biggest builder Salini Impregilo, told journalists last week.

"While the rest of the country was wondering how to shut down (as Italy went into lockdown in early March), here the question was how to go on," said Salini, whose company is rebuilding the bridge with shipbuilder Fincantieri.

Completion work for the new structure measuring about a kilometre (half a mile) will include tarmacking and the installation of transparent wind barriers and solar panels. Stringent road tests will follow.

"We hope to have the first traffic cross the bridge by the end of July," Salini said.

Architect Piano, a Genoa native whose building designs include the Centre Georges Pompidou in Paris and The Shard in London, said the celebrations would be muted out of respect for the victims and their families.

Autostrade, which runs almost half of Italy's motorway network, has been accused of failing to maintain the bridge amid allegations of falsified safety reports and in-house pressure to slash maintenance costs.

Atlantia, the parent group of Autostrade, is controlled by the powerful Benetton family.

Autostrade is under judicial investigation, along with several transport ministry officials, for culpable homicide.

A total of 74 people are accused in the legal case, which has seen investigators use a super computer to trawl through thousands of documents and files seized from Autostrade offices and the transport ministry.

Ella Ide contributed to this story from Rome.