The piece-by-piece process of cutting up and removing debris from the collapsed Francis Scott Key Bridge in Baltimore is underway, though officials don’t yet know how long the painstaking effort will take to clear the key shipping channel.
According to the multi-agency unified command overseeing the incident recovery, demolition crews began cutting away the top of the north side of the collapsed bridge truss with the support of two barges equipped with 650 cranes and 330 tons on March 30. The ton section was cut, handled and lifted the next morning, according to Maryland Gov. Wes Moore (D), adding that the process took about 10 hours. The removal of the second section of 350 tonnes was to take place on Monday.
As the parts are removed, they will be brought by barge to the logistics complex near the Tradepoint Atlantic waterfront, according to information from the unified command. There, a 230-ton land crane will unload the remains for inspection and processing and eventually transport to a yet-to-be-identified disposal site.
Each operation to lift debris from the collapsed armor requires extensive engineering planning and analysis, Moore added, out of concern for worker safety and the uncertain effect of the remaining debris, as well as the 4,700 containers loved ones who are still on board the freighter Dali, which remains ashore at the site.
“Every time we move a piece of a structure, the situation could become even more dangerous,” Governor Moore said at a news conference Monday. “We must move quickly, but we cannot be careless.”
A massive Chesapeake 1000 crane owned by Donjon Marine Co. Inc. of Hillside, NJ, is not part of this initial wreck work, but will be used to lift the large beam section of the downed bridge, estimated to weigh several thousand tons, to rest. on top of the containers stacked on the bow of Dalí. There are currently more than 50 water assets on site, with additional cranes to be dispatched to site in the coming days.
Limited visibility and dangerous water conditions have complicated efforts to survey the channel to determine how to remove the debris and ensure the Dali can eventually be refloated and removed from the channel.
U.S. Coast Guard Rear Admiral Shannon Gilreath explained that below the waterline and along the bottom, “these beams are essentially tangled, intertwined, which makes it very difficult to figure out where to eventually cut so we can make them into more manageable sizes. to lift them out of the water.” He characterized the components as 3-foot, 1.5-inch-thick steel I-beams.
Even with the help of advanced sonar to map the area, “it’s proving more difficult than we expected,” Gilreath said.
These conditions have also prevented resumption of the search for four construction workers who were part of a concrete repair crew working in the main span when the incident occurred. Two workers survived, and the bodies of two more were recovered the day after the collapse.
Unified Command also reported that Baltimore Gas & Electric has depressurized an underlying natural gas pipeline that spans the width of the canal. Although apparently undamaged by the incident, the pressure reduction to 35 psi is intended to protect the pipeline from hazards and risks as recovery operations continue. This will include removing sections of the collapsed bridge that extend to the bottom of the canal.
Another concern is the possible leakage of hazardous materials that were being transported aboard the Dali. Some of the more than 50 containers known to hold substances such as corrosives, flammables and some miscellaneous hazardous materials were broken in the collapse, according to the National Transportation Safety Board. More than 3,000 feet of boom surrounding the ship has so far prevented any spread of contaminants, state officials say.
On Monday, Baltimore’s harbor master opened a temporary alternate channel under a still-standing bridge section on the north side of the 50-foot-deep, deep-draft main shipping channel for commercially essential and emergency response vessels . Marked with buoys and lighted aids to navigation maintained by the US Coast Guard, the temporary channel has a control depth of 11 feet, a horizontal clearance of 264 feet, and a vertical clearance of 96 feet. A second, 15-foot-deep temporary channel to the southwest of the main channel will be laid in the coming days after the existing piles are removed.
Gilreath also hopes that the initial removal of the debris will allow for the addition of a third channel with a potential controlled depth of up to 25 feet deep. Once open, 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 very complicated operation,” Governor Moore said of the many variables associated with removing the debris and the Dali and ultimately clearing the main channel to fully reopen water access to Baltimore Harbor. “There are still things we don’t know yet about how this will translate over time.”
