Experts warned Genoa highway bridge had been weakened by 20% months before collapse

Engineers said in February that corrosion of the metal cables supporting the Genoa highway bridge had reduced the bridge's strength by 20 per cent – months before the structure's deadly collapse last week, reports said.

Despite the findings, the Italian magazine Espresso wrote that "neither the ministry, nor the highway company, ever considered it necessary to limit traffic, divert heavy trucks, reduce the roadway from two to one lanes or reduce the speed" of vehicles on the key artery for the northern port city.

A large section of the Morandi Bridge collapsed on 14 August during a heavy downpour, killing 43 people and forcing the evacuation of more than 600 others living in apartment buildings beneath another section of the bridge.

Prosecutors are focusing their investigation into the cause of the bridge's collapse on possible faulty maintenance or design flaws.

After workers heard creaking noises coming from the part of the bridge that was still standing, firefighters suspended an operation to allow evacuated residents to retrieve their belongings from apartments under the bridge.

The Italian news agency ANSA reported that officials have ruled out that the sound could be caused by wind, and that more checks are under way.

Work is continuing to clear tonnes of bridge debris that cascaded onto a dry riverbed below.

Espresso cited the minutes of a meeting of the Genoa public works superintendent, which included Roberto Ferrazza, an architect named to head a government commission looking into the disaster, and Antonio Brencich, an engineer who has been outspoken about the bridge's flaws.

Former transport minister Graziano Delrio told a news conference that "no one ever signalled the necessity of limiting traffic" on the bridge.

Espresso reporter Fabrizio Gatti said a reduction of 20 per cent strength would not be significant in a modern bridge, but on a structure with the known defects of the Morandi Bridge it should have merited swifter, more decisive action.

Mr Gatti said: "Everyone was well aware of the situation on that bridge."

Bidding on a 20 million euro (£17.9 million) contract to reinforce two of the major supports for the bridge, including one that collapsed, was scheduled to close next month.

The Italian government, meanwhile, appeared divided on how to proceed in relation to Autostrade per l'Italia, the company that operated the section of highway that collapsed.

Transport and infrastructure minister Danilo Toninelli was quoted by the Milan daily Corriere della Sera as saying that he supported the nationalisation of Italy's toll highways.

"Think of all the revenues that would return to the government through tolls, to use not to donate to shareholders' dividends but to reinforce the quality of service and security on our roadways," Mr Toninelli was quoted as saying.

Deputy premier Matteo Salvini told reporters he remains in favour of public-private cooperation in infrastructure.

Premier Giuseppe Conte said procedures have begun to revoke Autostrade per l'Italia's concession to operate some 1,900 miles of Italian highways, about half of the total major routes operated by private companies.

Italy's main union confederation estimates it would cost Italy between 15 billion and 18 billion euros (£13.45 billion to £18.4 billion) to revoke the highway rights.

The company which owns Autostrade, Atlantia, lost 9.5 per cent in its shares to 17.50 euro in trading, after a late opening due to volatility.

It shed 22 per cent last Thursday, the first trading day after the government announced its intentions, before returning to positive gains on Friday.

Associated Press