Work to stabilise the approach deck on the Pennsylvania bank of the river began last week and involves the structure being jacked slowly back to its original position from the temporary towers that were installed beneath it after the fracture was discovered.

The major bridge which connects Pennsylvania with New Jersey over the Delaware River is to remain closed indefinitely while engineers attempt to stabilise it after the discovery of a fracture in a 350mm steel I-beam truss member. The PA Turnpike Commission and New Jersey Turnpike Authority’s preliminary evaluation of the fracture on the bridge determined the need for a continued closure. Construction work is under way to stabilise the bridge while engineers carry out a more comprehensive assessment and structural analysis necessary in order to develop a permanent repair plan.

Initial stabilisation work involved adding new plates to reconnect the fractured truss pieces in an attempt to prevent further movement. A sample of the fractured truss was taken to a lab at Lehigh University for forensic analysis to help determine the cause of the fracture.

The four-lane Delaware River Bridge is jointly owned by the PA Turnpike Commission and New Jersey Turnpike Authority; it carries Interstate 276 over the Delaware River. The 2km-long bridge opened to traffic in 1956 and it carries more than 42,000 vehicles per day. The structure is a combination of girder-floorbeam spans, continuous deck truss spans and through-arch truss spans. In addition to spanning the main channel of the Delaware River, the bridge also crosses several other roads and railways.