Construction of Virginia’s first fully hydraulic bridge is right on schedule with overall project completion slated for July 2005.
The five-lane, two-leaf bascule structure is being built in the 270-year-old community of Great Bridge in Chesapeake, VA, by Tidewater Skanska Inc. Crews from the Virginia Beach-based Tidewater Skanska began construction in December 2001 to replace the existing 280-ft. (85 m), double-swing bridge where State Route 168, also known as Battlefield Boulevard, crosses the Albemarle and Chesapeake Canal.
“The present bridge, adequate at the time it was built for a rural area, is seriously overloaded – carrying more than 30,000 vehicles per day, which is double its design capacity,’’ said Annie T. Davis, project manager for the Norfolk District of the U.S. Army Corps of Engineers. “It is considered functionally obsolete due to its narrow roadway and poor alignment with the connecting roads as it now connects a multi-lane highway through a heavily traveled area serving a busy urban commercial center.”
The existing two-lane, low-level bridge was built by the Corps of Engineers and opened to traffic in August 1943. The Corps awarded an $18.9-million contract in July 2001 to Tidewater Skanska, but the cost for the company’s work has since risen to $20.5 million due to some minor revisions.
“We’re constructing the new bridge 7 feet away from the existing bridge which is unaffected by our work. The project is on schedule and we’ve completed about 80 percent of our work,” said John Birch, project manager of Tidewater Skanska. “We still have to hang the truss sections and power up the bridge. We should complete our work by February 2004.”
The total project cost is approximately $46 million, which includes the contract for the actual construction of the state-of-the-art span and additional money, which has been earmarked for the five-lane approach roads and a smaller culvert bridge.
Davis said the project schedule calls for traffic to be shifted to the two eastern lanes of the new bridge in December and for the entire undertaking, including the approach roadways, to be finished in July 2005. The Corps is expected to award the contract for the road construction within 120 days after opening bids on May 29.
Corps officials say the new bridge will significantly improve traffic flow which, in turn, will enhance air quality along the approach corridors and in nearby communities. The road will be widened to five lanes from Wayne Avenue southward to Causeway Drive.
“The existing bridge is made of steel which heats up in the summer, gets stuck and won’t shut,” said Birch. “With the new bridge, there won’t be as many shutdowns for maintenance and repairs.”
Birch said the hydraulic bridge, designed by URS Corp. of San Francisco, CA, is practical in areas where workers are limited by the physical features of the property. He said the minimum height of a fixed span that can be constructed over an intracoastal waterway is 65 ft. (20 m).
"Land is premium in the area. Constructing a fixed bridge to go 65 feet over the area would have required the acquisition of a lot of real estate," said Birch.
When opened to traffic, the Great Bridge will extend 140 ft. (43 m) – or 14 stories – into the air. The bridge, which will stretch 220 ft. (67 m) across the waterway, will consist of two 110-ft. (33.5 m) leaves. Birch said the most difficult part of Tidewater Skanska’s job will be erecting the leaves this summer.
"We can’t close the channel to river traffic or road traffic for any significant length of time. We had two options where we could build the bridge in the up position or build it off site and bring it in," said Birch. "The leaves are being built a few miles down the river in our company’s equipment yard."
Tidewater Skanska will use its 350-ton (317.5 t) stiff-leg derrick to transport the leaves to the construction site. The first leaf will be transported on July 22, while the second one will be delivered to the site on Aug. 5. Birch said the channel will be closed for three days on each instance.
Birch said the derrick, nicknamed Samson, was constructed by Tidewater Skanska many years ago. The primary pieces of on-site equipment being used are a Manitowoc 3900 and a Manitowoc 4000, both of which are owned by the construction company.
Initially, Tidewater Skanska officials believed the project would require the excavation and treatment of approximately 5,000 cu. yd. (3,823 cu m) of petroleum-contaminated soil and the treatment of up to one million gallons of contaminated water pumped from the bascule cofferdams.
However, Birch said the levels of contamination were not as bad as originally expected.
"Most of the ground was not contaminated, but we did have lead in the water that had to be treated," he said. "Less than 100,000 gallons of water had to be treated and we employed innovative techniques to separate the canal water from the ground water using sealed sheet piles.
"We drove sheet piles into the ground and sealed them so the water couldn’t get in. We intercepted the clean water and pumped it off before it got close to the contaminated water," he explained.
Birch said about 19 subcontractors are working on the project, which also entails the demolition of five existing buildings, replacement of the fender system and reconstruction of approximately 1,000 linear ft. (305 m) of bulkhead.
The bridge will sit on two main foundations, each featuring two pile caps that measure 50 ft. (15 m) long and 21 ft. (6.4 m) wide with a thickness of 6.5 ft. (2 m) Each pier is constructed with 500 cu. yd. (382 cu m) of heavily reinforced concrete drawspans which are built with 350-ton (317.5 t) plate girder steel and 300 tons (272 t) of reinforced concrete counterweight positioned overhead. The segmental girders upon which the bridge will glide weigh about 135,000 lbs. (61,235 kgs) each.
Birch said the materials being used in the construction include 2,000 tons (1,814 t) of structural steel and 18,000 linear ft. (5,486 m) of piling.
"We’ve had no trouble getting materials to the site and some of the large loads of steel have weighed 70 tons. Everything has come by road," said Birch. "We didn’t have to do anything special to get access to the site."
Once the bridge is completed, it will be owned, operated and maintained by Chesapeake’s Public Works Department. If a power outage occurs, the new bridge will continue to operate with the use of a standby generator. Two mechanical rooms under the concrete approaches will house the hydraulic machinery.
The Great Bridge has an unusual and calamitous history going back to 1770 and the existence of a 40-yd. (36.5 m) structure at the site. During construction of the Albemarle and Chesapeake Canal system from 1850-59, a swing drawbridge was built at the site to replace the narrow low-level bridge, which was later destroyed in the Civil War.
The bridge was subsequently replaced with inferior wood and collapsed in 1868. It was rebuilt again, only to be hit by a steamboat a year later.
The canal was sold to the federal government in 1913 and work soon began to widen and deepen the waterway. A steel bascule, single-drawspan bridge was built in Great Bridge in 1916. The government eventually removed the lock at Great Bridge and boating traffic used a detour, which had been dug out of the old bed of the Southern Branch to the immediate north of the canal.
Once the lock was removed, the bypass was filled. Complaints from boat operators, fishermen and residents prompted the Corps of Engineers to approve the 1932 construction of a new lock in Great Bridge. The existing bridge opened to motorists in 1943.