The Delaware River Bridge, which connects New Jersey and Pennsylvania and has been closed since inspectors found a crack in a supporting truss on Jan. 20, will remain closed for a minimum of eight more weeks.
That’s the conclusion of an emergency engineering task force led by the 60-year-old bridge’s co-owners, the New Jersey Turnpike Authority and the Pennsylvania Turnpike Commission. The 1.2 mile-long bridge carries 42,000 vehicles daily via Interstate 276 between Burlington Township in New Jersey and Bristol Township in Pennsylvania.
The crack was discovered on Pennsylvania’s side of the bridge during a routine inspection of a bridge painting project. According to the Pennsylvania Turnpike Commission, the fracture caused the section of the bridge between the two supporting piers to drop by about 2 inches as the load was redistributed. Those components were not designed to carry a heavier load so the bridge was closed.
The task force, which consists of more than 20 public and private engineering design, construction and transportation entities, concluded that an early April reopening is the best-case scenario.
“That best-case scenario entails repairing the I-beam by constructing a permanent splice to reconnect the fractured section,” PTC Chief Engineer Brad Heigel said. “But before that can occur, crews must first realign the bisected segment by deploying eight temporary towers and hydraulic jacks to return the span to its original position.
“As load is transferred within the bridge, instrumentation will monitor the actual loads, stresses and displacements which will be compared to estimated outcomes from computer models,” Heigel added. “This monitoring — which involves affixing about 50 sensors to the structure — is the only way we can confirm that the splice is successful before we reopen the bridge.”
If the data gathered during load testing show that the fix didn’t work, a more complex partial reconstruction of the impacted portion would have to be tried, barring replacing the entire bridge.
© 2017, Transport Topics, American Trucking Associations Inc.
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