Experts say several factors may have contributed to the accident: from the possible use of poor-quality fuel to the fact that the bridge was designed for much smaller ships.
Shortly after midnight on Tuesday (26/03), the cargo ship Dali crashed into one of the concrete pillars supporting the Francis Scott Key Bridge, which crosses the port of Baltimore, in the state of Maryland, in the United States.
A large section of the 2.4 km long bridge collapsed immediately and eight workers who were working on site at the time of the collision fell into the water. Two were rescued the same day, the bodies of two others were recovered on Wednesday – and the search continues for the other four, all presumed dead.
The incident closed a major US port, raising fears there could be repercussions for global supply chains.
Investigators are investigating the causes of the accident. The ship’s data recorder has been recovered and could help shed light on what went wrong.
But experts say a number of factors – from the possible use of poor-quality fuel that led to a power outage or even the bridge’s design for much smaller ships – may have contributed to the collapse.
Contaminated fuel
A video of the crash shows the Dali losing power moments before the collision. A power outage may have caused the ship’s crew to lose control of direction, leaving them unable to control its trajectory.
Investigators are looking into whether any use of contaminated fuel may have played a role in the ship’s power outage. Impure fuel can cause problems with a ship’s engines and power generation.
“The ship was inoperable, with no steering and no electronics,” an official told Fox News.
“One of the engines sputtered and then stopped. The smell of burning fuel was everywhere in the engine room, and it was pitch black.”
As soon as it ran out of power, the ship headed uncontrollably towards the bridge. The crew’s efforts to mitigate the impact, including turning sharply into port and dropping anchor, ultimately proved futile.
“This is a really big ship. And the linear momentum and energy associated with moving this ship even just a few miles per hour is enormous,” says Sanjay Raja Arwade, a professor of civil engineering at the University of Massachusetts Amherst in United States.
In a press conference Tuesday, Transportation Secretary Pete Buttigieg said that the Key Bridge, as it is known, was “simply not designed to withstand a direct impact on a critical support pillar of a vessel weighing approximately 90 pounds, 7 million kilos”.
A bridge from the last century and a ship from this century
The Francis Scott Key Bridge was completed in 1977. At the time, the ships it was designed to pass were much smaller than today’s giants, including the 95,000 gross ton Dali.
“The ships that passed through Baltimore Harbor at the time are not even comparable,” says Norma Jean Mattei, former president of the American Society of Civil Engineers.
“The project life is so long – sometimes more than 100 years – that the needs of the facility can change in ways that are difficult to predict at the time of design and construction,” explains Arwade.
He said civil engineers often think about making the structures they design redundant, meaning one part can fail without the entire structure collapsing. But designing redundancy for the pillars supporting a long-span bridge would be “extremely difficult or impossible.”
He adds that other safety features, which could have helped, would have come at a cost and had limited effectiveness.
Experts said protective barriers appeared to have been installed near the bridge, but did not prevent the ship from collapsing.
It also appears that the bridge did not have a “bumper” – an extra layer of protection around the pillars – that could have absorbed some of the impact.
Mattei explains that mitigating risk is about analyzing probabilities when deciding where to spend money. Ultimately, the authorities may have felt that the likelihood of a huge ship hitting one of the bridge’s load-bearing pillars was too low to justify reinforcing them.
“We have a few dollars to invest,” he notes.
David Knight of the Institute of Civil Engineers believes that after this collapse, bridge owners around the world will consider how to ensure that a similar catastrophe does not happen again.
“Lessons will be learned and will help us design and build even safer bridges,” he says.
Source: Terra
Mary is a professional journalist, working at 247 News Update. She writes on various topics from world news to general interest article, providing readers with relevant and informative content. With years of experience, she brings a unique perspective and in-depth analysis to her work.
