Note: The text of this article was updated 4/3/24 to reflect new information.

Weather and water conditions are hampering the piece-by-piece process of cutting and removing wreckage from the collapsed Francis Scott Key Bridge in Baltimore, while officials consider potentially utilizing progressive design-build for a replacement bridge. Officials remain uncertain as to how long the meticulous effort to clear the key shipping channel will take.

One of the massive cranes removing the wreckage of the Francis Scott Key Bridge has a long and colorful history starting with a Cold War nuclear sub recovery. In 2017, ENR’s Nadine Post penned a detailed article on the Chesapeake 1000 crane.
See the article!

According to the multi-agency unified command tasked with overseeing the incident recovery, demolition crews began cutting the top portion of the collapsed bridge truss’s northern side supported by two barges equipped with 650- and 330-ton cranes on March 30. The first 200-ton section was cut, rigged and lifted the following morning, according to Maryland Gov. Wes Moore (D), adding that the process took about 10 hours. Removal of the second, 350-ton section was to take place on Monday.

However, at a press briefing April 3, the governor added that rain and thunderstorms are hampering removal of the section. 

As pieces are removed, they will be taken by barge to the nearby Tradepoint Atlantic waterfront logistics complex, according to information from unified command. There, a 230-ton land-based crane will offload the wreckage for inspection and processing, and eventual transport to a disposal site that has yet to be identified.

Every wreckage-lifting operation from the collapsed truss requires extensive engineering analysis and planning, Moore added, out of concern for worker safety and the uncertain effect of the remaining debris as well as the estimated 4,700 containers still aboard the cargo vessel Dali, which remains grounded at the site.

“Every time we move a piece of a structure, the situation could become even more dangerous,” Gov. Moore said at a Monday press conference. “We have to move fast, but we can’t be careless.”

A massive Chesapeake 1,000 crane, owned by Donjon Marine Co. Inc. of Hillside, N.J., is not part of this initial wreckage work, but will be used to lift the large section of downed bridge span—estimated to weigh several thousand tons—resting atop containers stacked in the Dali’s bow. More than 50 waterborne assets are currently on site, with additional cranes to be dispatched to the site in the coming days.

Limited visibility and hazardous water conditions have complicated efforts to survey the channel to determine how to remove the wreckage and ensure the Dali eventually can be refloated and removed from the channel. Crews are relying on sonar for imaging and mapping. Unified command is staged to begin lifting undamaged containers from the Dali once weather improves. Water sampling upstream and downstream the wreckage shows no contamination, the governor said.

U.S. Coast Guard Rear Admiral Shannon Gilreath explained that below the waterline and along the bottom, “these girders are essentially tangled together, intertwined, making it very difficult to figure out where you need to eventually cut so that we can make them into more manageable sizes to lift them from the water.” He characterized the components as being 3-ft, 1.5-in.-thick steel I-beams.

Even with the aid of advanced sonar to map the area, “It’s turning out to be more challenging than we expected it to be,” said Gilreath.

These conditions also have prevented the resumption of the search for four construction workers who were part of a concrete repair team working on the main span when the incident occurred. Two workers survived, and the bodies of two others were recovered the day after the collapse. 

Related Link (PDF):

ENR 1976 article on construction of Francis Scott Key Bridge

The unified command also reported that Baltimore Gas & Electric has reduced pressure of an underlying natural gas pipeline that spans the width of the channel. Though apparently undamaged by the incident, the pressure reduction to 35 psi is intended to protect the pipeline from hazards and risk as recovery operations continue. That will include removing sections of the collapsed bridge extending to the channel bottom.

Another concern is the potential leakage of hazardous materials that were being transported aboard the Dali. Some of more than 50 containers known to have substances such as corrosives, flammables and some miscellaneous hazardous materials were breached in the collapse, according to the National Transportation Safety Board. More than 3,000 ft of boom surrounding the vessel has so far prevented any spread of contaminants, state officials say.

On Monday, the captain of the Port of Baltimore opened a temporary alternate channel beneath a still-standing section of bridge on the north side of the main 50-ft-deep, deep-draft shipping channel for commercially essential and emergency response vessels. Marked with buoys and U.S. Coast Guard-maintained lighted aids to navigation, the temporary channel has a controlling depth of 11 ft, a 264-ft horizontal clearance and vertical clearance of 96 ft. A second, 15-ft-deep temporary channel to the southwest of the main channel will be established in the coming days once existing pilings are removed.

Gilreath is also hopeful that the initial removal of wreckage will allow the addition of a third channel with a potential controlled depth of up to 25 ft deep. Once opened, he said, the third channel “should allow us to move almost all of our tug and barge traffic in and out of the Port of Baltimore.”

“It’s a remarkably complicated operation,” Gov. Moore said of the many variables associated with removing the debris and the Dali, and eventually clearing the main channel to fully reopen waterborne access to the Port of Baltimore. “There are still things that we just do not yet know about how that’s going to translate into timing.”