There are still as many questions as there are answers in aftermath of the catastrophic March 26 collision between the container ship Dali and Baltimore’s Francis Scott Key Bridge. Investigators continue to probe the disaster, which knocked out the busy Port of Baltimore, claimed the lives of six migrant workers who were still on the bridge when it collapsed, and has prompted concerns about how vulnerable America’s sea bridges are to the increasingly massive ships that pass under them. Meanwhile, the political response to the tragedy has gotten pretty ugly, including some baseless and racist attacks on Baltimore officials. Below is a roundup of some of the smartest commentary and analysis on the collapse and what it means from engineers, maritime experts, pundits, and others.
Here's video of the collapse of the Francis Key Scott Bridge from this morning. The bridge was struck by a cargo ship just before 1:30 a.m. A search is underway for at least seven people. pic.twitter.com/FRGHeJ1gIe
In a post at the Conversation, Monash University civil engineering professor Colin Caprani explains what defenses the Francis Scott Key Bridge had in place to protect it in the event of a collision — and why they weren’t enough:
The bridge rests on four supports, two of which sit each side of the navigable waterway. It is these two piers that are critical to protect against ship impacts. And indeed, there were two layers of protection: a so-called “dolphin” structure made from concrete, and a fender. The dolphins are in the water about 100 metres upstream and downstream of the piers. They are intended to be sacrificed in the event of a wayward ship, absorbing its energy and being deformed in the process but keeping the ship from hitting the bridge itself.
The fender is the last layer of protection. It is a structure made of timber and reinforced concrete placed around the main piers. Again, it is intended to absorb the energy of any impact. Fenders are not intended to absorb impacts from very large vessels. And so when the MV Dali, weighing more than 100,000 tonnes, made it past the protective dolphins, it was simply far too massive for the fender to withstand.
Video recordings show a cloud of dust appearing just before the bridge collapsed, which may well have been the fender disintegrating as it was crushed by the ship. Once the massive ship had made it past both the dolphin and the fender, the pier – one of the bridge’s four main supports – was simply incapable of resisting the impact.
Satellite photos take after the collapse indicate that the Dali had indeed slipped past one of one of the four “dolphins” meant to protect the bridge pier.
At the New York Times, the Upshot’s Aatish Bhatia and Francesca Paris tried to determine the sheer force of the out of control container ship:
Our lowest estimate of how much force it would take to slow the Dali, if it were fully loaded, is around 12 million newtons, about a third of the force it took to launch the Saturn V rocket for the Apollo moon missions. And our higher-end estimates, reviewed by several civil engineering experts, suggest it is realistic to put the force of the impact with the pier at upward of 100 million newtons. “It’s at a scale of more energy than you can really get your mind around,” said Ben Schafer, a professor of civil and systems engineering at Johns Hopkins.
Experts disagreed on whether it was reasonable for any bridge pier to withstand a direct collision with a massive container ship. “Depending on the size of the container ship, the bridge doesn’t have any chance,” said Nii Attoh-Okine, a professor of engineering at the University of Maryland. He said that Baltimore’s Key Bridge had been performing perfectly before this accident occurred, and that he thought 95 to 99 percent of bridges would be damaged if such a container ship were to strike them. But Sherif El-Tawil, an engineering professor at the University of Michigan who reviewed our calculations, said it was feasible to design a pier that would stay standing after such an impact: “If this bridge had been designed to current standards, it would have survived.”
Modern bridges, designed in the age of ultralarge shipping containers, are typically built with stronger piers or protection systems around the piers that can either absorb or deflect the force of ship collisions. But the Key Bridge was completed in 1977, when standards were different and ships were far smaller.
Michael J. Chajes, a civil and environmental engineering professor at the University of Delaware, adds some historical context:
The Francis Scott Key Bridge was designed in the early 1970s. Construction started in 1972, and it opened to traffic in 1977. This preceded the 1980 collapse of the Sunshine Skyway in Florida, which was caused by a ship collision, similar to what happened in Baltimore. That bridge collapse led to the initiation of research projects that culminated in the development of a U.S. guide specification in 1991 that was updated in 2009. …
A pier protection system was installed when the Sunshine Skyway bridge was rebuilt, and it has been used on numerous other bridges. The same approach is currently being applied by the Delaware River and Bay Authority at a cost of US$93 million to protect the piers of the Delaware Memorial Bridge.
The Washington Post reports that Maryland officials were at the time aware of the danger a ship collision like the one that took down the Sunshine Skyway Bridge posed to the Key Bridge — and that was a ship was just over a third the weight of the Dali:
At the time of the Sunshine Skyway Bridge accident, the Baltimore Sun reported that a top state engineer said the Key Bridge couldn’t withstand a similar collision. “I’m talking about the main supports, a direct hit — it would knock it down,” the official said.
Current U.S. bridge design codes do not require the overhaul and retrofitting of old bridges to be more resistant to ship collisions, however.
Another civil engineer who spoke with Wired explained why the Key Bridge collapsed as quickly as it did:
“It’s a dreadful tragedy and something you hope never to see,” says David Knight, a bridge expert and specialist adviser to the UK’s Institution of Civil Engineers. But commenting on footage of the bridge collapse, he says he is not surprised by the manner in which it crumpled.
Large steel structures may seem invulnerable, but steel, explains Knight, is relatively lightweight for its size. As soon as it is pushed or pulled the wrong way with enough force, it can fold like paper. In this case, the Francis Scott Key Bridge was a “continuous,” or unjointed, bridge that had a 366-meter-long central truss section. (Truss bridges use steel beams, arranged in triangular shapes, to support their load.) The central truss was made up of three horizontal stretches, known as spans, with two sets of supports holding these above the water. It was the third-largest structure of its kind in the world.
“When you take a support away, there is very little in the way of robustness,” says Knight. “It will drag down, as we saw, all three spans.” The separate approach spans remain standing. There is nothing in Knight’s view that immediately suggests any structural problem with the bridge.
And he noted that more robust protection systems at the pier may not have prevented the catastrophe:
In more recent decades, bridge engineers have commonly incorporated defenses to reduce the potential damage by ship strikes when bridges are erected in similar locations, Knight says. These include hydraulic barriers and additional concrete around the base of bridge supports, for instance. However, even with such fortifications in place, heavy strikes can still cause devastating damage.
Arizona State University structual engineering professor Barzin Mobasher put it more bluntly to CNN: “No bridge, unless a fortress is built around it, could survive such an impact. A ship of that size, even if empty of any cargo, at that speed could still do that damage at the spot where it struck.”
Chajes also points out that owners of older bridges “have a tremendous challenge finding the financial resources needed to retrofit their bridges to satisfy the latest design codes and to account for the increased impact loads expected due to the heavier and heavier ships.”
And picking which aging infrastructure to reinforce, and when, is complicated too. Adds the Washington Post:
A 2022 Maryland freight investment plan included a proposal to spend $86 million to replace the concrete deck and important barriers on the Key Bridge. Such immediate safety-related fixes might have seemed more urgent than protecting bridges from hypothetical collisions.
Roberto T. Leon, a structural engineering professor at Virginia Tech, said bridge engineers wrestle with how to handle “high-consequence rare events” such as this week’s accident. “You buy safety at a certain cost,” Leon said, adding that the price of addressing very unlikely threats can soar. And even as engineers, and society, learn lessons and increase safety standards over the decades, some projects with known safety vulnerabilities are allowed to stay in operation.
“We change things,” Leon said. “But we have to grandfather existing structures because the cost of bringing things up to date would be enormous.”
Tugboats were not escorting the Dali at the time of the collision, nor was that required — and though two tugs rushed to assist the ship after its crew called for them, four minutes before the crash, it appears it was already too late to make a difference. Writing for the Telegraph, former ship captain Tom Sharpe says that the lack of a tugboat escort now looms large:
Many have asked why tugs weren’t used. This is an important point and points to broader questions that will be asked of Baltimore port control about their overall safety management system, something that is every bit as relevant to this accident as the ‘loss of control’ suffered on the ship. Dali was doing about eight knots at the time of the incident which is approaching the upper speed of most tugs, certainly the upper speed at which they can have any lateral effect on a ship of that size, so a tug forward ‘pushing off’ in the traditional sense would have struggled. But there is no reason (other than time and money) why she couldn’t have had a tug attached aft or at least had one close by. This would have given the ship so many more options. …
This ship (with a questionable engineering state) was navigating a narrow channel, at night, under a bridge which (it’s clear to everyone now) had zero resilience. Who was adding all these together and evaluating how the port safety resources should be managed, or were they just treating this like every other movement?
The Associated Press spoke to experts about this critical factor, as well:
Extended tugboat escorts aren’t required or even customary in Baltimore or at many other U.S. ports, mostly because of the costs they would add for shippers. But with the increasing size of cargo ships and the threat they pose to bridges and other critical infrastructure, some are questioning whether they should be.
“I’m a big fan of tug escorts,” said Joseph Ahlstrom, a member of the Board of Commissioners of Pilots of the State of New York, which regulates the state’s harbor pilots. “If applied early enough and effectively, yes, a tug escort could prevent a collision with the bridge or with another ship, or going aground.”
Tugboat regulations are stricter for oil tankers, but in order to protect the environment, rather than bridges. And shipping companies typically resist more stringent rules:
Maritime experts told the AP that the Baltimore disaster highlights how each individual port makes its own tugboat rules, resulting in a patchwork across the nation, and how competition among ports for business from cost-conscious shipping companies has trumped calls for extended tugboat escorts that can add tens of thousands of dollars to every transit.
Baltimore’s port, operated by the state of Maryland, ordinarily uses tugboats to help maneuver big ships out of their docks and doesn’t require extended tugboat escorts into the port’s channel and broader Chesapeake Bay unless ordered by local harbor pilots or the U.S. Coast Guard over safety concerns tied to weather, traffic, cargo or mechanical issues. Shippers can also request tugs. …
“Tugs are a big upfront cost and a lot of companies don’t want to pay for that,” said Sal Mercogliano, who writes a widely followed shipping blog. “And if Baltimore starts mandating it, you’re going to see ships go to Norfolk, Philadelphia, New York — wherever is cheapest.”
As Boston Globe columnist Renée Graham points out, some thoughtless-at-best Republicans have tried to use the disaster to further their crusade against DEI efforts:
On X, Anthony Sabatini, a Republican congressional candidate in Florida, posted a video of the bridge collapsing with the words “DEI did this.”
Not condolences to families unaware of the fate of their loved ones after the bridge was struck by a massive cargo ship. Not prayers for first responders then still hoping to find survivors amid the dangerous wreckage. But a mendacious and racist remark that implies that people of color are only in high-ranking jobs because of their race, not their qualifications. On social media, racists referred to Baltimore Mayor Brandon Scott, who is Black, as a “DEI mayor,” and claimed DEI stands for “didn’t earn it.”
Phil Lyman, a Republican Utah state representative, claimed in a post on X that the bridge collapse “is what happens when you have governors who prioritize diversity over the wellbeing and security of citizens.” Maryland’s Port Commission has six commissioners. But Karenthia A. Barber, the sole Black woman on the commission, was singled out in a post by a right-wing group that Lyman retweeted. Lyman, who is running to be Utah’s governor, later posted “DEI=DIE” and the hashtag #DEIisPoison. When he was questioned by the Salt Lake City Tribune on Tuesday, he blamed the racist posts on his social media staff. Days later, the posts had not been deleted.
The Baltimore Banner’s John-John Williams IV spoke with Mayor Scott about the attacks:
“We know what these folks really want to say when they say DEI mayor,” he told The Banner. “Whether it is DEI or clown. They really want to say the N-word. But there is nothing they can do and say to me that is worse than the treatment of my ancestors. I am proud of who I am and where I come from.” …
Scott is far from a “DEI mayor.” He wasn’t appointed; he was elected by voters in a city with one of the largest Black populations in the country. And Scott defeated several Black candidates to become Baltimore’s 52nd mayor.
Philadelphia Inquirer columnist Will Bunch argues that more attention should be paid, instead, to the people who lost their lives in the tragedy, including a 38-year-old father of two, Maynor Yassir Suazo Sandoval, and five other migrant workers who had all come to the U.S. seeking a better life — only to die because they were fixing potholes in the wrong place at the wrong time:
In normal times, the deaths of these six migrants would serve as a tragic parable about how our American landscape was etched into existence by the big dreams, hard-earned sweat, and occasionally the sacrifice of each new generation of Maynor Suazos as they came from Ireland, then from Italy, then from Honduras and all over the globe.
But these are not normal times. Even before the first divers had arrived on the chaotic scene, an army of pampered coffee shop keyboard commandos and a few overpaid TV hairdos were denying the reality that the Baltimore bridge disaster was a tragic disruption of the diversity that keeps America running.
He concludes that “when the Dali cargo ship demolished that bridge support on Tuesday, it also obliterated all the ridiculous lies and myths our demagogues have been spreading around immigration”:
These six workers who perished were not “poisoning the blood of our country,” they were replenishing it. This is a moment of clarity when we need to reject the national disease of xenophobia and restore our faith in the United States as a beacon for the best people like Suazo. They may have been born all over the continent, but when these men plunged into our waters on Tuesday, they died as Americans.
President Biden quickly called on Congress to fund the reconstruction of the bridge, but there’s been pushback from Republicans, as Politico reports:
“It was kind of outrageous immediately for Biden to express in this tragedy the idea that he’s going to use federal funds to pay for the entirety,” Rep. Dan Meuser told Fox Business on Thursday. “This is a crisis situation, but it needs a plan, not a knee-jerk spend reaction.” …
Those comments didn’t sit well with Democratic Rep. Kweisi Mfume, in whose district the bridge is located. He called Meuser’s position “short-sighted,” noting that the Pennsylvania Republican co-chairs the Congressional Coal Caucus, which advocates for one of the main exports of the Port of Baltimore.
“This is not a Chesapeake Bay, Baltimore issue. It affects the supply chains nationwide and will have an impact economically, nationwide, unless that bridge is rebuilt,” Mfume told POLITICO. “After hearing Dan Meuser’s comments today, I’m a little taken aback and I don’t know how to respond to that except that he may not realize — or may not have realized at the time — that his issue — coal — in particular is going to be dramatically affected by this.”
He added: “I just don’t know how in Pennsylvania coal country, how anybody could be lauding the fact that we should slow down or not get totally involved as the federal government in rebuilding the bridge and reopening the harbor.”
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