In 1796, Isaac Tomlinson built a wood and sandstone covered bridge spanning the Quinnipiac River near New Haven, CT, charging farmers a toll to cross the bridge that led to the market downtown. Since then, three versions of this bridge have spanned the Quinnipiac where it empties into New Haven Harbor. Now, a massive fourth version of the Tomlinson Bridge is taking shape.
The new Tomlinson Bridge is believed to be the second largest lift span bridge ever built in the United States. This bridge will replace a traditional two-lane drawbridge that was built in 1926.
Lift span or vertical lift bridges are unique because they reduce the necessary length of elevated roadways leading up to the bridge, while simultaneously providing a clear channel for ship and barge traffic. This is accomplished by lifting up the entire over-water portion of the bridge (known as the lift span) vertically for ships to pass underneath, then lowering it back down to permit motorists to cross.
The lift span on the new Tomlinson Bridge measures 280 ft. (85.3 m) long and 92 ft. (28 m) wide and weighs approximately 6 million lbs. (2.7 million kg). Raising the massive lift span will be accomplished by a series of motors, reduction gears, drive shafts, hoist drums, cables, sheaves and 3-million-lbs. (13.6 million kg) counterweights suspended from each of the twin 150-ft. (45.7 m) tall support towers on either end. When operational, the system will raise the lift span section 62 ft. (18.8 m) in the air to allow large ocean-going vessels to pass beneath.
In 1992, plans for the new bridge began because it was determined that the existing structure’s 120-ft. (36.6 m) channel berth was too narrow for some of the larger vessels that repeatedly collided with the bridge as they headed up and down the river. The problem reached the critical stage in 1995 when a barge slammed into the old bridge, causing considerable damage and making it impossible to close its gates. This led to the old bridge’s demolition. The new bridge is designed with more than twice the channel berth and will be able to safely accommodate much larger and taller vessels.
When dredging for the new wider channel began, workers discovered that a large amount of waste building material from the three previous bridges had to be removed, which added nine months to the project. Even more time was lost when the project’s original contractor encountered problems and filed a claim against the Department of Transportation in 1999. In the spring of 2000, the bonding agency responsible for the project awarded the contract to complete the job to Cianbro Corporation, based in Pittsfield, ME.
For the Tomlinson Bridge project, Cianbro has used more than 220 pieces of its own equipment including three ringer cranes, two-yard cranes, and a number of JLG telescoping booms. The company made arrangements with Shaughnessy Crane Service, an NES Company, to provide it with whatever else it needed, such as additional aerial work platforms. Although Cianbro has 18 JLG booms in its fleet, the company knew it would need more because of the heights it needed to reach when doing the steel erection. Shaughnessy, with its large inventory of JLG products was able to provide what Cianbro needed.
Scott Gorton, regional sales manager of Shaughnessy in New Haven, worked with Bill Richardson, Cianbro’s yard supervisor, to coordinate the additional equipment as it was needed.
“This job is moving so fast our equipment needs change almost daily,” said Richardson. “When we need something, we need it now and it must be ready to go to work when it gets here. They’re [Shaughnessy] really service oriented and their equipment always arrives in first-class condition.”
With more than 8,000 tons (7,200 t) of structural steel to erect on the lift span and support towers, telescoping booms are an extremely important tool for the more than 25 ironworkers on the job. When completed, they will have installed more than 45,000 1-in. (2.5 cm) bolts into each of the towers and more than 90,000 bolts into the lift span section.
“Booms are the only way to safely access overhead areas,” said Pete Fournier, steel erection superintendent of Cianbro, “and we chose to buy JLG products for our own fleet and use them when we rent because they work well for us. Our team members are used to working with them. They know how to operate the controls and the JLG booms never give us any trouble. In fact, we’re using two 120-ft. JLG machines right now to finish off the iron work on the East tower.”
In addition to working on the huge twin towers, JLG telescoping booms are being employed to bolt together the massive lift span section of the bridge that is being constructed on top of a huge 280 ft. by 140 ft. (85.3 by 42.6 m) assembly barge that is moored near where the towers are being built. When the steel erection is complete on the towers and lift span section, and the sheaves, counterweights and other components of the bridge’s operating system have been installed, the assembly barge carrying the lift span section will be released from its mooring and floated into position between the two towers.
As the tide comes in, the barge will be lifted by the high tide to a point where the lift span structure can be attached to the cables on the towers.
When the tide goes out, the assembly barge will flow with the water away from the lift span structure that was built on its deck, and the entire fabricated metal section will be in place.
“We’ll probably need a whole bunch of JLGs then,” said Richardson. “We only have a limited amount of time to make the connections before the tide starts to recede, so we’ll depend on the aerials to help us do what we have to do in the short amount of time we have to do it.” CEG