March 9, 2016

DOT Puts Historic Bridge Back in Business

The historic stone masonry arch bridge over Stony Brook south of town on Route 206 re-opened Sunday evening after almost two weeks of emergency repair work by the New Jersey Department of Transportation (DOT).  The truck detour will remain in place until the bridge is fully restored.

DOT officials, engineers and Historic Preservation Commission members are already moving ahead with plans for permanent reconstruction of the 1792 bridge, with an emphasis on strength, safety, durability, and a sensitivity to history.  

Princeton Municipal Engineer Bob Kiser commended the DOT for their work under pressure.  “The DOT worked very, very quickly in putting the bridge back into operation,” he said.  “They worked nights and weekends.  I applaud the DOT in getting the bridge back in operation as quickly as they did.”  Mr. Kiser also stated that the DOT “have been sensitive to the historic nature of the bridge.”

A parapet on the southbound side of the bridge collapsed on Monday, February 22 on 206 near the entrance to the Hun School.  The DOT erected a precast construction barrier on both sides of the bridge to protect the damaged parapet.

While inspecting the parapet and bridge, NJDOT engineers discovered cracks and voids that had developed within the supporting stone arches.  They immediately closed the bridge.

Crews also discovered significant scour (sediment, such as sand and rocks from around bridge abutments or piers, potentially compromising the integrity of the structure) at the footing of the bridge.

The DOT installed a portable dam around the footing of the bridge and made drainage improvements to reduce the impact of potential flooding or water damage due to heavy rains.  Finally the bridge was repaved to ensure a safe driving surface.

Temporary overnight lane closures during off-peak hours may be necessary for the next few weeks.  NJDOT will provide advisories before any traffic pattern changes.  The bridge now has a posted weight limit of 20 tons.

In addition to the historic arch bridge reconstruction, DOT officials have also determined that the adjacent flood plain bridge, constructed in 1924, just to the south of the stone arch bridge, is also in serious condition and needs to be replaced.

Mr. Kiser described the project—including reconstruction of the parapet walls on either side of the historic bridge, strengthening the arches and reinstalling stone where necessary, along with replacement of the flood plain bridge— as “an extensive job.”  The stone masonry arch bridge, which in 1792 replaced a 1738 brick masonry bridge, is a National Historic Landmark.  Both bridges are part of the Lincoln Highway and the Kings Highway Historical District.

The Princeton Historic Preservation Commission will formulate recommendations for repair and reconstruction and a written response to the DOT plans by March 21, to be forwarded to the state Historic Preservation Office for their April 22 meeting.  The DOT plans to seek approval from the Department of Environmental Protection and the Historic Sites Council next month and hopes to be underway with the repair and reconstruction project by summertime.