After years of planning and research, work is under way to replace the Lindsay C. Warren Bridge on U.S. 64 over the Alligator River. The North Carolina Department of Transportation (NCDOT) is overseeing the $450 million project, which will improve conditions for motorists and the more than 4,000 boats that pass through the swing span each year.

"The current bridge is 65 years old and is prone to mechanical issues that can mean a 99-mile detour for motorists if the bridge is not functioning," said Pablo Hernandez, NCDOT resident engineer.

NCDOT photo

"It requires constant monitoring for concrete repair, along with maintenance and upkeep of the mechanical components of the swing span."

Because the bridge has spent more than six decades in a corrosive environment, it's considered structurally deficient. Opting for a new fixed-span bridge, just north of the current one, will allow unimpeded transit for both vehicular and maritime traffic.

The bridge also is the main route to access the Outer Banks from the west and is considered a critical hurricane evacuation route. The Alligator River

Bridge is part of the U.S. 64 corridor that leads to inland points west.

According to Hernandez, the first pile on the project was driven in February 2025.

"The test pile program is an approach that NCDOT takes on all large coastal bridges. The program allows the department to simulate pile installation scenarios, so that the proper foundation and/or proper

equipment can be selected for engineering and economic reasons.

"The test pile was successful in that we were able to establish appropriate pile lengths, which benefits us both structurally and economically by saving us from a prolonged completion time."

Skanska USA serves as prime contractor for the new bridge that will connect Tyrrell and Dare counties. Hernandez said the construction and development company has a proven track record, which makes it a good fit for the project.

"Skanska has experience working with some of the components being installed on this bridge, such as large pre-cast pilings. They have a regional office in nearby Hampton Roads, Va., where they have engineering and equipment resources readily available."

NCDOT photo

Hernandez said when working on a bridge replacement, maintaining vehicular traffic on U.S. 64 and marine vessel traffic on the Intracoastal

Waterway is essential. However, since workers are not constructing in the same footprint as the old bridge, issues with utilities and impacts to users are not as difficult.

Still, he acknowledged that performing construction and getting workers and materials delivered in a remote area can be difficult.

"Working on the Alligator River is similar to working on an inland sound with a large, open expanse. These expanses bring with them the possibility of

significant wave action and high winds, not only on the surface of the water, but at the top of the cranes.

"We have been fortunate to this point was hot, it was relatively dry. Of course, in the future, we will always need to contend with any summer/fall tropical systems or fall/winter/spring nor'easters that may occur over the next four years."

Last summer, crews placed concrete for the low-level bridge supports and installed temporary work trestles in shallow water/lowland wetlands areas that will facilitate building the 3.2-mi.-long bridge.

With more than 50 percent of the pilings for the entire structure have been installed, Crews paused in-river pile driving between July 15 and Sept. 30 for an environmental moratorium related to fish spawning.

NCDOT photo

Construction calls for building two 12-ft. travel lanes with 8-ft. breakdown lanes. The concrete deck on the bridge will be 9-in. thick cast-in-place concrete that will be screeded with a bridge finishing machine to provide the lanes and shoulders.

Regarding excavation, there's .5-mi. of roadway work on either side of the bridge that involves moving unsuitable material to a depth of 6-8 ft. and backfilling it with a sandy granular material so that the roadway embankment can be built on a stable surface.

Heavy machinery being used includes three barge-mounted ringer cranes; three barge-mounted crawler cranes; and two crawler cranes on work trestles, as well as two large tugboats, three push-boats and six aluminum work skiffs. Six barges that are used for equipment or transporting materials also are required, along with excavators, bulldozers, rollers and dump trucks for roadway construction. D180 diesel hammers are being used to install the 36-in. square and 54-in. diameter cylinder pre-stressed

piles. Piles range in length from 90-120 ft. long and are embedded in the bed of the river 60-90 ft.

Pre-cast concrete piling; 36-in. square 54-in. diameter cylinders; pre-stressed concrete girders; 45-in., 72-in. and 96-in. Florida I-beam girders and cast-in-place concrete of at least 4,500 psi that utilizes glass fiber reinforced polymer bar are among the chief materials needed to complete the work.

Fall 2029 is the expected date to open the new bridge to traffic, with demolition of the current bridge scheduled for spring 2030. All components of the structure will be removed in their entirety and will be processed into recyclable products or used as an inland artificial reef.

Hernandez said working on a project that will have such a lasting impact is meaningful for all involved.

"The department and community are pleased to see work on a new structure that provides for a stable and reliable vital transportation corridor between the coast and inland communities. It means changing the landscape and providing a reliable traffic corridor for the state and its visitors for generations to come, while improving a vital hurricane evacuation route."  CEG