Regional weather services had issued a storm warning for the morning of the collapse and the national police force said on Twitter the disaster happened amid a "violent cloudburst."
"The fact that there was reported to be a storm at the time may or may not be particularly relevant. In addition, ongoing work on the bridge may or may not be partly responsible for the collapse," said Ian Firth, former president of the Institution of Structural Engineers.
The civil protection agency could not confirm witness accounts that the bridge cracked after being hit by lightning.
Two years ago Antonio Brencich, a professor specializing in reinforced concrete construction at Genoa University, called the bridge a "failure of engineering" during an interview. "That bridge is wrong. Sooner or later it will have to be replaced. I do not know when. But there will be a time when the cost of maintenance will be higher than a replacement," he told local TV station Primocanale.
The Morandi Bridge — named after its designer Riccardo Morandi — was built in 1967. Italy's CNR civil engineering society pointed out on Tuesday that the working lifespan of bridges built in the 1950s and '60s was some 50 years. Tens of thousands were built during those decades using reinforced concrete, the best known technology at the time.
Corrosion and fatigue
Mehdi Kashani, an associate professor in structural mechanics at Britain's University of Southampton, said maintenance issues and pressure from "dynamic loads" such as traffic and wind could have resulted in "fatigue damage in bridge components."
"As this reinforced and pre-stressed concrete bridge has been there for 50 years, it is possible that corrosion of tendons or reinforcement may be a contributory factor," said Firth.
Comments made by CNR suggest the bridge should have reached the end of its 50-year lifespan around last year. The bridge was undergoing reinforcement work at the time of the collapse and was under constant monitoring.
The cost of updating and reinforcing 1950s and '60s bridges is more than it would cost to destroy and rebuild them, CNR said. As such, it called for a major program to replace most of the bridges with new ones which would have a lifespan of 100 years.
Tuesday's tragedy will likely reopen a debate on the need to invest billions on major infrastructure projects. Within hours of the bridge collapse, Italy's government said it showed the country needed to spend more to improve its dilapidated infrastructure, ignoring EU budget constraints if necessary.
"We should ask ourselves whether respecting these (budget) limits is more important than the safety of Italian citizens. Obviously for me it is not," said Deputy Prime Minister Matteo Salvini, who is also leader of the nationalist League party and interior minister in a power-sharing government.
Whatever the cause of the collapse, Salvini said he wanted the names of those to blame because a tragedy like this in 2018 was not acceptable. "They will have to pay, pay for everything, and pay a lot," he said.
kw/rc (AP, DPA, Reuters)
Cars plunge into void
A 100-meter section of Genoa's Morandi Bridge collapsed on Tuesday morning amid torrential downpours and violent storms. At least 35 cars and heavy vehicles are believed to have been on the section when it caved in, causing them to plunge some 45 meters into the void below.
Italy's busy motorway viaduct
The bridge over the northwestern port city was one of Italy's main viaducts, connecting the A10 motorway towards France and the A7 up to Milan. The incident also took place on the eve of Ferragosto, a major Italian holiday, meaning traffic was likely to have been busier than usual.
Rescuers scramble to find survivors
Less than an hour after the collapse, authorities had already indicated the number victims was likely to be in the dozens. Italy's transport minister, Danilo Toninelli, said the bridge collapse appeared to be an "immense tragedy." International leaders, including German Chancellor Angela Merkel and France's Emmanuel Macron, paid tribute to the victims.
Rescue efforts continue through the night
Rescue workers continued to scour the rubble and wreckage through the night with the hope of finding more survivors. Alongside firefighters and emergency services, another 1,000 locals volunteered to help in the rescue efforts. According to the Interior Ministry, as many as 16 survivors were found wounded beneath the rubble, including 12 in serious condition.
Death toll rises
By Wednesday morning, Italian Interior Minister Matteo Salvini said the death toll in the collapse had risen to 35, including three children aged eight, 12 and 13 years old. Officials also warned that the number of dead was likely to rise further, as rescue workers began moving the largest pieces of debris.
Tragedy spurs political fallout
Italy's Giuseppe Conte interrupted his holiday to visit the scene of the collapse. While Conte reserved his words to praise the rescue workers, his ministers started pointing fingers. Transport Minister Toninelli said the company managing Italy's highways would have its contract revoked. However, his 5Star Movement party has been criticized for downplaying the need for infrastructure investments.
Cause of collapse still unknown
While the precise reason behind the disaster is still unknown, investigators believe it was potentially caused by a lightning strike, an engineering failure or corrosion. Italy's CNR civil engineering society has warned that the lifespan of bridges built during the 1950s and 60s was only about 50 years. The Morandi Bridge had been in use for more than five decades.
Apartment buildings in danger
Toninelli, who is also minister of infrastructure, has said the apartment buildings standing almost under or next to the bridge might have to be demolished. Some 630 people living in the apartment buildings have been evacuated. Toninelli said on Facebook that lodgings would be found for them.