By Philip Sean Curran, Staff Writer
The state Department of Transportation plans to fix an 18th-century masonry arch bridge over the Stony Brook and replace another bridge abutting it all at the same time, a DOT official said Monday.
“It makes sense to move this and do it all at once,” director of project management Dana Hecht of the DOT told the Princeton Historic Preservation Commission. “So that’s what the department is planning on doing.”
The older Stony Brook Bridge, constructed in 1792, reopened Sunday after being closed for emergency repairs. A stone parapet on the southbound side collapsed Feb.22; a subsequent inspection found cracks and voids in the stone arches that support the bridge and what the state called “significant scour” or the removal of sediment at the footing of the structure.
The state made short-term repairs but said a long-term fix is necessary.
“We believe that there needs to be more extensive rehabilitation of the bridge and as soon as possible,” said engineer David Hutchinson of Arora and Associates, the consulting firm the DOT has retained for the project. “We want to do everything we can, to the extent possible, to restore the history of the bridge. But there might need to be some minor alternations to provide safe passage for the motoring public.”
Based on a concept he presented, the state would reconstruct and raise the parapet wall on both sides to a uniform height of 3 feet 6 inches for traffic safety, pour concrete to strengthen and reinforce the arches that support the bridge and reconstruct the stone area below the parapet as necessary. Town engineer Robert V. Kiser, who attended the commission meeting, said afterward that a project of that scope would take three to fourth months to complete, on extended work hours of two eight-hour shifts “at a minimum.”
Elsewhere in his remarks, Mr. Hutchinson touched on the history of the bridge, the oldest in New Jersey carrying highway traffic. The state must follow federal Secretary of the Interior guidelines for repairing a historic structure.
“We realize this is a significant piece of history, we want to save this for Princeton, for New Jersey, for the nation,” he said. “We want the structure to last.”
But one commission member voiced concerns and pointed to a lack of experience Mr. Hutchinson’s firm had in dealing with bridges of this kind.
“I’m really frightened by this project. I think that the conception of the project is just completely wrong,” said Cecelia Tazelaar in suggesting the DOT turn to an engineering firm with a “track record” of rehabbing historic masonry arch bridges.
Piggybacking on her comments, fellow commissioner Robert von Zumbusch said one of the defining characteristics of the bridge is the height and shape of the parapet wall. He challenged the DOT on whether there are traffic accident records to show the height of the wall is a “problem.”
“I do think that some sort of proof is necessary, because I am not the least bit convinced that really is a safety problem,” he said.
For her part, Ms. Hecht defended the Arora firm by saying the DOT has “100 percent faith in the designers that we have on board.”
“We will not be putting something back that is not to standard,” she said. “But safety is not an option for the DOT.”
DOT said it did not have a price tag for how much fixing one bridge and replacing the other one, known as the flood plane bridge, would cost.
In the meantime, there will be a truck detour “until the permanent fix is in place,” Ms. Hecht said.
