Afrigather 
New bridge replaces a pair of 50-year-old buildings in North Carolina.
Photograph courtesy of Balfour Beatty
Regardless of six-month fish moratoriums, development of a 3,200-ft-long bridge connecting Carteret County in North Carolina on to Harkers Island has been accomplished a yr forward of its authentic schedule.
Demolition of the unique Earl C. Memorial Bridge, a metal drawbridge, is slated to wrap up this month whereas Bridge No. 96, which continued the connection previous a fishing pier causeway, is being repurposed as a pedestrian bridge to supply entry to the middle island and a renovated Straits Fishing Pier.
The brand new fixed-span bridge, constructed over the straits to the east of the 2 50-year-old buildings, supplies a direct path for drivers touring to and from the mainland. With a 45-foot navigational clearance, it permits boats to go unimpeded and safely permits motorists to journey with out ready for bridge openings that might take so long as quarter-hour.
The construction sports activities carbon fiber-reinforced polymer (CFRP) strands and glass fiber-reinforced polymer (GFRP) bars to higher face up to the coastal setting. “Some years again we needed to change all of the core slabs due to the salt water and corrosion” on the drawbridge, says Brad McMannen, North Carolina Dept. of Transportation venture supervisor. “Concrete was falling off and the [swing span] was getting locked up. From a upkeep standpoint, it was time for one thing new and totally different.”
Balfour Beatty gained the $68-million job in fall of 2021. “As soon as we bought on website, we talked concerning the [possibility] to complete forward of schedule by a yr,” says Mark Johnnie, Balfour Magnificence’s U.S. Civil CEO.
The contractor value-engineered the pre-drilling course of to hurry up the schedule, says Peter Distefano, Balfour Beatty senior venture supervisor. To get rid of the necessity to carry out a full excavation previous to pile placement, the group leveraged a probe by roughly 5 ft of a tough layer. “The borings confirmed a reasonably mushy layer beneath that,” he says. “Basically the pile excavation referred to as for a 42-in. casing to be put in to drill. So we had that casing and modified it right into a probe. We used that to vibrate by the layer.”
Delivery the 28 girders by barge as an alternative of by truck additionally saved time, as did including further shifts. “The letting was in late July, and we have been awarded the job in early August,” remembers Distefano. “The moratorium began Oct. 1. We needed to begin up quick and be driving manufacturing piling and trestle piling within the two months between,” he says.
He provides: “We had a reasonably robust workforce within the space. We had simply completed the Surf Metropolis Bridge simply south of this venture so we had quite a lot of good crews able to go.”
As a result of bridge being designed with CFRP and GFRP supplies, there have been strict necessities which didn’t permit any ferrous materials within the development of the bridge. “We used friction collars on the piles to assist the concrete substructure,” says Distefano. “Numerous exterior helps have been wanted when it comes to falsework.” The bridge bearings and anchor bolts include stainless-steel, provides Johnnie.
Demolishing the outdated twine slab-style bridge is “a reasonably simple course of,” provides Distefano. “We’ve got two cranes on two barges—one crane engaged on the middle pivot pier space, the second working the method spans and twine slab sections.”
The brand new bridge, which McMannen says carries about 3,500 each day autos, opened final December with a big neighborhood turnout. “It’s outstanding how they supported the development,” says Johnnie, noting a Fb fan web page and locals bringing crews meals. “It was one thing to behold.”
Aileen Cho, ENR’s senior transportation editor, is a local of Los Angeles and recovering New Yorker. She studied English and theater at Occidental Faculty, the place a reporter instructing the one present journalism course inspired her to use for the LA Instances Minority Enhancing Coaching Program. Her journalism coaching led to her first tales about transportation, working as a cub reporter with the Greenwich Time. Her work has appeared within the Los Angeles Instances and New York Instances. A lot of her experiences with engineers and contractors have impressed materials for her different theater productions manner, manner off Broadway. For ENR, Aileen has traveled the world, clambering over bridges in China, touring an airport in Abu Dhabi and descending into darkish subway tunnels in New York Metropolis. She is a daily at transportation conferences, the place she finds that airport and mass transit engineers actually know tips on how to have enjoyable. Aileen is all the time desirous to hop on one other flight as a result of there are such a lot of attention-grabbing initiatives and individuals, and he or she will get bored with throwing her cats off her pc in her house workplace in Lengthy Seashore, California. She is a really conflicted Mets/Dodgers fan.
