NC Bridge Replacement Completed Early

WEDNESDAY, MARCH 20, 2024


Officials in North Carolina have announced that construction on a 3,200-foot-long bridge connecting Carteret County in North Carolina directly to Harkers Island has been completed a year ahead of its original schedule.

According to reports, the new fixed-span bridge, constructed over the straits lying east of the two 50-year-old bridges it is replacing, will provide a direct path for drivers traveling to and from the mainland. The project will be fully completed this month as one of the old bridges is scheduled to be demolished, while the other will be repurposed into a pedestrian path.

About the Project

The project was reportedly set to begin construction in 2020, but became embroiled in controversy when two nearby property owners filed a petition in July 2019 claiming NCDOT did not follow the proper environmental review processes for the project.

The project was then reportedly put on hold while litigation was ongoing, and a departmentwide budget shortfall as a result of the coronavirus pandemic added additional uncertainty to the project timeline.

The parties involved reportedly reached a settlement in September 2020, before a scheduled hearing on the petition. As part of the settlement, NCDOT agreed to redesign part of the bulkhead of the new bridge, among other stipulations. 

NCDOT then awarded the contract for the new Earl C. Davis Memorial Bridge construction back in 2021 to Balfour Beatty.

According to the report, development and design costs came out to around $1,720,000, property acquisition was $1,320,000 and utility relocation cost $5 million. With construction costs around $60 million, the entire project had a total estimated price tag of just over $68 million.

“Generally speaking, as a project gets through the final design, the estimate would constantly evolve based on needs and actual design factors,” Haviland said of the project’s estimated cost increase at the time. “Inflation and supply shortages due to COVID lead [sic] to cost increases too.”

According to a recent report from Engineering News-Record, the demolition of the original Earl C. Davis Memorial Bridge, a steel drawbridge, is scheduled to conclude this month, while the neighboring Bridge No. 96 will be turned into a pedestrian bridge for access to the center island and a renovated Straits Fishing Pier.

With a 45-foot navigational clearance, the new bridge will reportedly allow boats to pass uninterrupted and motorists to travel without waiting for bridge openings that could take up to 15 minutes.

The bridge reportedly contains carbon fiber-reinforced polymer (CFRP) strands and glass fiber-reinforced polymer (GFRP) bars to help the structure withstand the coastal environment.

“Some years back we had to replace all the core slabs because of the salt water and corrosion” on the drawbridge, said Brad McMannen, NCDOT Project Manager. “Concrete was falling off and the [swing span] was getting locked up. From a maintenance standpoint, it was time for something new and different.”

Peter Distefano, Balfour Beatty Senior Project Manager, stated that the contractor value-engineered the pre-drilling process to speed up the schedule. To eliminate the need to perform a full excavation before pile placement, the team reportedly leveraged a probe through about 5 feet of a hard layer.

“The borings showed a fairly soft layer beneath that. Essentially the pile excavation called for a 42-in. casing to be installed to drill. So we had that casing and modified it into a probe. We used that to vibrate through the layer.” he explained.

“Shipping the 28 concrete girders by barge instead of by truck also saved time, as did adding extra shifts. The letting was in late July, and we were awarded the job in early August. The moratorium started Oct. 1. We had to start up fast and be driving production piling and trestle piling in the two months between.”

Because the bridge was designed with CFRP and GFRP materials, there were strict requirements which did not allow any ferrous material in the construction of the bridge.

“We used friction collars on the piles to support the concrete substructure,” said Distefano. “Lots of exterior supports were needed in terms of falsework.”

The bridge bearings and anchor bolts consist of stainless steel, added Johnnie.

Demolishing the old cord slab-style bridge is “a fairly straightforward process,” Distefano stated. “We have two cranes on two barges—one crane working on the center pivot pier area, the second working the approach spans and cord slab sections.”

Bridge Opening

The new bridge, which McMannen stated would carry around 3,500 daily vehicles, opened last December with a large community turnout. According to a report from Carolina Coastal Online, a ribbon cutting ceremony was held at the end of last year to celebrate the bridge’s official opening.

NCDOT also reportedly held the event on the mainland side in the community of Straits. Afterwards, NCDOT reportedly allowed anyone interested to walk across the bridge before opening it to vehicular traffic.

Additionally, a follow-up report states that 103-year-old Harkers Island resident Houston Salter took an honorary “first drive” across the bridge, courtesy of the NCDOT. Communications Officer Lauren Haviland called the gesture a “rare, community-driven moment.”

“It’s something the community really pushed for, and it’s going to be a great way to mark a new beginning for the bridge,” she said. “Mr. Salter was here when the first bridge was constructed mostly out of wood and was here for the second bridge. Now he can witness the third one that will be here for quite a while.”

According to the report, there are two reasons for the fast completion of the project. One is that Balfour Beatty developed a method to place piles for the bridge more efficiently than expected, also taking advantage of mild weather during the in-water construction periods of Oct. 1 to April 15 in 2023.

“It was a bit of a race to get those piles in by April 15 so they could begin work on the deck of the bridge,” McMannen said. “Balfour Beatty was able to come up with a method to expedite getting the piles in quicker, and they were able to hit those milestones early.”

Additionally, the structure will reportedly be the state’s first-ever fully reinforced glass and carbon fiber bridge. The new design has been used in other states such as Virginia, Michigan and Florida, and is expected to withstand the highly corrosive coastal environment and extend the lifespan of the bridge.

“This is the largest structure using this technology in the state,” NCDOT Division Engineer Jeff Cabaniss said. “It’s going to be a much more resilient bridge. It’s high enough for boat traffic, and there is no steel on the deck, so the corrosive impact of the saltwater will be greatly reduced.”

According to the report, NCDOT had worked with North Carolina State University to research the new technology. An initial research project was launched in 2013 to study the use of non-corroding carbon fiber polymer in concrete bridge elements.

   

Tagged categories: Bridges; Bridges; Carbon Steel; Construction; Demolition; Department of Transportation (DOT); Infrastructure; Infrastructure; NA; North America; Polymers; Program/Project Management; Roads/Highways; Stainless steel; Steel; Transportation

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