The new Francis Scott Key Bridge is expected to be longer and taller than its fallen predecessor, but not steeper.
A 143-page Maryland Transportation Authority document seeking a “categorical exclusion” — meaning the rebuild won’t require a yearslong process analyzing alternative bridge possibilities — was approved by the Federal Highway Administration this week. In it, the authority outlined the new bridge’s potential dimensions, which would satisfy Coast Guard parameters.
“The proposed fixed bridge should provide at least 230 feet of vertical clearance above mean high water,” Coast Guard Rear Admiral Shannon Gilreath wrote in a June letter to the transportation authority.
The document, written by the transportation authority and the Maryland State Highway Administration, noted changes between the new bridge’s proposed dimensions and the old span: It would have 230 feet of vertical clearance, as opposed to the old bridge’s 185 feet, and a 1,400-foot main span length, compared with 1,200 feet.
Vertical clearance is the distance from the water — in this case, the Patapsco River — to the bridge deck, and it dictates what size ships can fit under the structure. The length of the main span is the horizontal distance between the two primary supports, making room for the navigational channel.
In recent years, some ports, including New York/New Jersey and Savannah, Georgia, have increased the heights of existing bridges or at least planned for the possibility. Raising a bridge’s height is often a costly task, but allows for larger ships to pass under.
Rebuilding the bridge to offer 230 feet of vertical clearance would not immediately open the Port of Baltimore to even more massive ships. Oceangoing vessels headed to Baltimore still need to sail under the Chesapeake Bay Bridge in Annapolis, which has 185 feet of vertical clearance, or, in some cases, under a series of shorter bridges along the Chesapeake and Delaware Canal, including the Chesapeake City Bridge.
It likely would be decades (after the existing Bay Bridge is knocked down) before ships needing higher clearances would be able to sail into Baltimore. But the new Key Bridge will be built to last at least 75 years and potentially, well over a century, so building the bridge to such a height would be an effort to future-proof the port.
In Georgia, authorities are considering replacing the 33-year-old Talmadge Memorial Bridge, which has 185 feet of vertical clearance with a 230-foot one. A spokesperson for the Georgia Department of Transportation previously told The Baltimore Sun that inaccessibility for larger ships is “potentially stifling future growth” of the Savannah port.
The Maryland Transportation Authority wrote in their document that “there is a trend toward even larger vessels” and “cargo ships are expected to increase in size due to the cost savings of utilizing larger ships.”
“Accommodating future ship navigation and traffic on the Patapsco River is important to maintaining the vitality of the Port of Baltimore and commerce in Maryland and the Mid-Atlantic region,” the document stated.
Cargo ships much larger than the ones calling on Baltimore and the U.S. East Coast currently exist, but even if bridges were built to be a mile high, it would be challenging for the largest ones to visit the East Coast, for a variety of logistical reasons. Still, building a taller bridge readies a port for changes in the shipping and cruise ship industry generations from now.
A bridge with 230 feet of vertical height would be among the highest on the East Coast. The proposed bridge’s towers — that is, its maximum height — would be 500 to 550 feet tall, per the authority’s document. That would make it substantially taller than the old bridge (358 feet) or either of the Bay Bridge’s spans (354 and 379 feet).
Deciding upon a bridge height requires balance: It needs to be tall to allow for larger ships — and rising sea levels — decades from now, but not so tall as to make a project needlessly expensive.
Capt. Jeffrey Monroe, a master mariner and education director for the International Association of Maritime and Port Executives, said last month that, were it up to him, he would build the Key Bridge to allow for 225 feet of vertical clearance. Of the proposed 230-feet of air draft, he said Thursday it would be “more than adequate” for the foreseeable future.
“230-foot is actually a pretty reasonable height,” said Monroe, who consulted on the $1.7 billion project to increase the height of the Bayonne Bridge, which connects New Jersey and Staten Island, New York, by 65 feet to 215 feet.
To eventually reach 230-feet of air draft at the Key Bridge, BGE powerlines — installed between 2020 and 2022 — would have to be moved or raised. Currently standing adjacent to the old bridge, those lines allow for 214 feet of vertical clearance.
The Coast Guard’s vertical clearance recommendation is “conditioned on modification of the existing powerline crossing adjacent to the location of the proposed bridge,” according to the Coast Guard’s June letter. The letter said a feasibility study should be conducted in coordination with the Army Corps of Engineers and BGE.
Asked whether it would be feasible to increase the height of those power lines, a BGE spokesperson did not answer directly, but offered a statement that, in part, noted the company had received input from the Maryland Port Authority when the lines were designed in 2018.
“The monopoles used in the project are among the tallest in America, ensuring that Port of Baltimore operations were not impacted by the installation of overhead transmission lines. We are in close communication with officials about the future reconstruction of the Key Bridge to ensure the safety of our equipment and determine how we can support the project,” BGE’s statement said.
Higher clearance eventually could pave the way for vessels even larger than the Dali, the container ship that lost power before crashing into a pier and decimating the Key Bridge on March 26, into Baltimore. Despite Coast Guard inspections, ships have engine problems — including a cargo ship that lost power earlier this month in the Port of Baltimore. Such incidents can endanger port infrastructure, which is the subject of a Coast Guard probe launched since the collapse.
To fortify against potential ship strike, the proposed Key Bridge would have “pier protection islands,” according to the transportation authority’s document. The authority also is exploring pier protection at the Bay Bridge, with an initial budget of $145 million and a target completion date of winter 2027-28.
Although the proposed Key Bridge would be taller, it would not be steeper (its 4% grade would be similar to the original). To reach its increased height, though, the proposed bridge would be 2.4 miles, which is 0.7 miles longer than the original, although the document states the precise length “will be determined during final design.”
“Engineering assumptions for the replacement bridge” were based on a cable-stayed bridge, according to the document, although that design has not yet formally been decided upon.
The state hopes to select a builder of the estimated $1.7 billion bridge by Labor Day, and that team would begin designing the bridge soon— as well as demolishing the existing pieces of the old span.
The transportation authority also released a request for proposals (RFP) last week for a “General Engineering Consultant.” Proposals are due Aug. 19, and that contract, worth $75 million, will be awarded by Feb. 2025. The consultant will be separate from the team selected to build the bridge and will act as the transportation authority’s engineering representative for the rebuild and will manage the builder. The consultant, per the RFP, cannot be a firm that is involved in the building project.
At least 90% of the rebuild will be funded by the federal government, but Maryland officials continue to seek full federal government funding, as President Joe Biden, who has six months left in office, promised earlier this year. If the federal government does not cover the full bill, a cost of roughly $170 million would fall on the state.
Bruce Gartner, the authority’s executive director, brought up the “discussions on the Hill regarding the 100% funding,” during Thursday’s monthly transportation authority board meeting.
“We still are hopeful for that, and it’s an ongoing process,” he said.
