Oregon Iron Works Inc. already has started construction of a second 680-ton truss.

The two massive structures, each 290 feet long, are destined in spring 2009 for the Puget Sound area’s Hood Canal Bridge, where they will connect floating bridge pontoons to state Highway 104.

Close to 60 people worked on the first truss during its construction, said Tom Hickman, sales and marketing manager of Oregon Iron Works.

The company removed a wall from the building where the truss was manufactured and used 16 55-ton power dollies to roll it outside. It took more than 25 people on the ground and behind the scenes to move the structure, Hickman said.

Next spring, after the second truss is complete, both bridge sections will be transported by barge to Puget Sound.

The trusses are made of tubular supports like those used on oil rigs, and are designed to handle the harsh marine environment of the Hood Canal, according to the Washington State Department of Transportation.

Though Oregon Iron Works began assembling the truss in October, fabrication of the structure’s individual pipe sections started in 2004, according to the state Department of Transportation. Design work started in 2000.

Oregon Iron Works’ $25 million Hood Canal Bridge manufacturing contract also includes a lift span and two A-frames, said Theresa Gren, transportation spokeswoman.