Good weather has helped speed work on the Interstate 276 bridge, officials said, making them optimistic it will not need to be partially reconstructed or completely replaced.
"Our best-case scenario is what's playing out right now," turnpike chief engineer Brad Heigel said.
He said inspectors have found no other major structural problems.
The 1.2-mile-long bridge has been closed since Jan. 20, when a painting crew found a cracked 14-inch steel truss under a westbound travel lane on the Pennsylvania side. That section of interstate typically carries 42,000 vehicles daily.
Crews have sent 44 4-inch steel cores for metallurgical testing at a university but do not expect to find any problems, he said.
Similar tests on samples from the site of the crack did not shed new light on the cause of the fracture, he said.
"It pretty much demonstrated a simple fact - that it's 1956 steel," Heigel said.
A 20-foot section from around the site of the break was recently taken down and is also being sent away for testing.
So far, $12 million in construction contracts have been issued, although there are other major costs for professional services. Pennsylvania and New Jersey, which own the bridge together, are splitting the costs.
Both states carry insurance on the bridge, Heigel said. A total cost, including lost tolls, has not been determined. The bridge connects the Pennsylvania and New Jersey turnpikes.
"We're cognizant of costs - we always are," he said. "We brought in the best of the best across the nation."
The cause of the damage also has not been nailed down, although engineers believe the use of plug welds at the point of fracture were part of the problem.
"We feel very confident there are no other misdrilled holes in the tension members in any of the other truss sections," he said.
Heigel said it also is possible that an unpermitted load put too much weight on the structure, and temperature may have played a role.
Officials still aren't sure when the fracture occurred, although they have fielded reports of a loud noise in that area in mid-December that could be connected.
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