Before a massive structure can again stand above the Patapsco River, some smaller ones will need to be erected.

Trestles would jut out from either side of the river to provide a platform for construction of the replacement Francis Scott Key Bridge, according to a recent environmental request from the Maryland Transportation Authority.

The authority already requested approval from the Maryland Department of the Environment for the rebuilding project, but last month submitted an amendment to allow for the construction of the temporary steel piers.

The initial ask would have allowed construction of the span solely via marine access, but the state-selected construction company, Kiewit, requested the ability to build via water and trestles, authority officials said. That prompted the amendment request.

A short pier for barge access would stick out just beyond the land on both sides, while longer piers, sitting 9 feet above the river and built to carry heavy vehicles, would protrude closer to the center of the proposed span.

The temporary trestles, expected to stand for the bulk of the yearslong rebuild, would create about 400,000 square feet of accessible area above the water. The two lengthy trestles would stop short of the federal navigation channel, allowing ships to continue to pass through.

Remaining portions of the original Key Bridge will be demolished this winter or spring, the authority has said, and the construction of the trestles would likely follow in the spring, said Brian Wolfe, the authority’s director of project development. Construction of the actual bridge — which is expected to be cable-stayed and significantly taller than the old span — would then follow.

The trestles would be strong enough to support trucks delivering concrete and other materials and their width, 57 feet, would provide enough room for trucks to pass one another, or for a vehicle to drive by an operating crane.

“The crane, when it swings, there’s enough room for a vehicle to actually still go behind it,” Wolfe said. “So it’s not going to stop traffic while it’s making a maneuver.”

Department of the Environment officials listened to public comments at a hearing about the amended plan Monday evening at a volunteer fire department in Edgemere attended by a couple dozen people.

In addition to a handful of public comments from citizens who were concerned about contaminants in the water and trucks rattling through neighborhood streets — and one who advocated for a dual-span, Bay Bridge-style replacement of the Key Bridge — Del. Richard Metzgar and State Sen. Johnny Ray Salling, both Republicans, spoke.

Shortly after the Key Bridge was destroyed by the Dali container ship on March 26, killing six construction workers, President Joe Biden vowed that the federal government would fully fund the rebuild.

Congress has not authorized that spending, meaning that it’s possible the bridge would be 90% federally funded (the default for a federal highway replacement project) with 10% paid for by the state.

That 10% could equate to nearly $200 million.

If Congress does not act this month, the onus would fall on a new Congress and President-elect Donald Trump in January. Asked if he expected a Trump administration and Congress to approve 100% federal funding, Salling said he expects to have an opportunity to “work with him.”

“I think we’ll be able to fill his ear,” Salling said of Trump, “and we’ll move forward.”

The new Key Bridge is expected to open in fall 2028 and cost between $1.7 billion and $1.9 billion.

“There’s gonna be some growing pains and we’ll be fussing, we’ll talk about the traffic and so forth,” Metzgar said during Monday’s public comment period. “But ladies and gentlemen, we will get through it, and it will be a beautiful, bigger and better bridge.”