The unrelenting growth in the size of Container Ships. From https://www.politico.com/news/2024/03/27/baltimore-bridge-design-fender-00149398
With (no) apologies to Condoleeza Rice, who, while reluctantly testifying before the 9/11 Commission, infamously said that no one could have envisioned terrorists hijacking airliners and flying them into skyscrapers, despite a Tom Clancy thriller published in the 1990s having used the idea of terrorists hijacking an airliner and flying it into the dome of the U.S. Capitol... (By the way, Condi had a supertanker named after her.)
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The Loss of the Francis Scott Key Bridge
The drawing above is the lead illustration in this Politico story. The "teu" in the illustration means twenty-foot equivalent unit. A teu is a (somewhat imprecise) unit of volume that is based on a shipping container that is 20 feet long.
The story's headline is: Outmoded bridge design likely contributed to catastrophic loss in Baltimore.
The sub-head is: After a Florida bridge collapse tragedy, bridges were required to be built with protective “fenders” — but not until the 1990s.
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The subhead refers to changes in design recommendations made after a fatal accident in Tampa Bay, Florida. Existing bridges like the Francis Scott Key Bridge, which spanned the Patapsco River just downstream of the the entrance to the main portion of Baltimore Harbor, must have been grandfathered.
You have, by now, probably seen several stories about the destruction of the Francis Scott Key Bridge, which carried a segment of Interstate Highway I-695 over the Patapsco River near the entrance to the main portion of the Port of Baltimore in the State of Maryland. The NeoPanamax Container Vessel, the MV Dali, lost power on its way out of the port around 1:30 A.M on March 26, 2024.
As a result, the MV Dali lost its ability to maneuver and struck one of the pillars supporting the Francis Scott Key Bridge. The collision led to a loss of structural integrity of the Bridge, and to the Bridge’s quick collapse. Six lives were lost… construction workers, immigrants from Mexico and from Central America, who came to the U.S. seeking a better life and to provide for their families.
Here is a video that provides video of and some observations about the collision:
When I first saw a news video of the collision, my initial reaction was: Wow, the pillars of that bridge look really exposed! As I read about the incident, I learned that there are concrete objects in the water, akin to bollards but called dolphins, that were supposed to protect the bridge from approaching vessels. The dolphins were obviously inadequate.
It is now painfully obvious that the engineers who designed the Francis Scott Key Bridge back in the 1970s never envisioned the mushrooming growth in the size of Container Vessels.
When an object (say, a car, or a truck, or a ship) is put into motion, it acquires kinetic energy and momentum. The amount of kinetic energy that the object acquires will depend upon the mass of the object and the square of the object's speed. (The momentum depends on the mass and the speed.)
If a moving object suddenly collides with another object, all of the moving object's kinetic energy will attempt to set the other object in motion. (Think of a Cue Ball striking an Eight Ball.) If the other object is not easily moved, the energy released as a result of the collision can cause substantial physical damage.
This New York Times article states that the authors' lowest estimate of how much force it would take to slow the MV Dali, if it were fully loaded, is around 12 million Newtons. That's about one-third of the force that it took to lift off of the launch pad at Cape Kennedy the Saturn V rockets that carried Apollo astronauts during the first moments of their trips to the Moon in the late 1960s and the 1970s. It's no wonder that the collision destroyed the Francis Scott Key Bridge.
What is a wonder to me is why, as ships got larger and ever larger, no ever one took steps to protect the Bridge, e.g.: mandating the use of escort tugboats until the large vessels had cleared the bridge and had made it to open water; or building protective structures in the areas surrounding the Bridge's piers that might have absorbed some of the shock, or that that might have diverted the ship, or both.
The thought never occurred to anyone that behemoth ships might pose a threat to the Bridge? Apparently not.
Speaking of tugboats, the MV Dali has very limited ability to maneuver. It has only a single screw (propeller), mounted along the main axis of the vessel. For sideways thrust, and for maneuvering in ports, MV Dali has a single 3,000 kW (4,000 hp) bow thruster. Usually, it must rely upon tugboats for assistance when leaving or arriving at a dock.
This Washington Post article, headlined, "Officials studied Baltimore bridge risks but didn’t prepare for ship strike," states, in pertinent part:
And after [the 2007 bridge collapse in] Minneapolis, the focus wasn’t on building the kind of massive and costly barriers that might have had even a chance of stopping a ship like the Singapore-flagged Dali from sending the Key Bridge crumpling into the Patapsco River, said the former senior transportation official.
“It never occurred to anybody,” he said.
Hard to believe, but hindsight is always 20/20... or so they say.
When a replacement Bridge is designed, the designers and whoever approves the design will have to address these issues.
Here are two about using tugboats to shepherd large vessels:
So, did no one ever think about using Shepherding tugs, or other means of protecting the Bridge’s pillars. Or, not to go C.T., did lobbyists for the shipping industry quietly smother any concerns in their cribs?
I supposed that we should not find it all that surprising that the destruction of the Bridge has spawned numerous and disgusting conspiracy theories and Blame Biden and Blame DEI and Blame Immigrants remarks by Right Wing Nut Jobs, including Congressional Representatives Marjorie Taylor Greene (RWNJ-Ga) and Nancy Mace (R-SC).
President Biden has stated his desire that the Federal Government cover the cost of replacing the Bridge. Predictably, the Right Wing is voicing reluctance, even though the now-shuttered Port of Baltimore is a principal export port for thermal coal. (I thought that they love coal.)
It is quite a contrast to what happened during the Dubya Administration. With nary a peep, Congress appropriated sufficient funds to fully cover the cost of constructing a new bridge to replace the one in Minneapolis, Minnesota that carried an Interstate Highway across the Mississippi River and that failed in 2007.
There is no reason whatsoever why Congress should not take the same approach now, even if it feels the need to float some bonds. As a Marylander who is concerned about our State and its workers, I myself would buy some of those bonds.
The continuing economic losses warrant prompt action.
However, the replacement bridge is going to have to be better protected that the Francis Scott Key Bridge was.
