By Philip Sean Curran, Staff Writer
Representatives of the state Department of Transportation will meet Monday with the Princeton Historic Preservation Commission to review options for permanent repairs to an historic but damaged 18th century bridge on Route 206 over the Stony Brook.
The town has said the bridge has a “damaged” foundation area that will require crews to pump in concrete to stabilize the foundation and immediate area. But the crossing has historical protections, so long-term repairs must be done in a historically sensitive way.
“Obviously, you want to preserve both the historic integrity of it and also the structural integrity of it,” Mayor Liz Lempert told reporters earlier this week.
They said the bridge would “possibly” remain closed into next week.
After a stone parapet on the southbound lane collapsed last week, authorities did further inspections finding cracks and voids in the arches that hold up the bridge. The state also was concerned about the southern abutment or end of the crossing, the town said.
Mayor Lempert said a diver, who is also an engineer, went into the water to look at the foundations of the bridge. “They are damaged,” she said.
In particular, there is erosion of the soil that supports the structure, town engineer Robert V. Kiser said.
The mayor said the state was putting in temporary dams on Monday to divert the water to give authorities a “much better look at the state of the foundations of the bridge.”
“Once they’ve done that analysis,” she said, “they will have a better sense of how long the repairs are going to take them.”
A stretch of Route 206 between Hutchinson Drive and Lovers Lane has been closed in both directions since last week, so motorists have had to take detours to avoid the closure. The town has not received a firm timetable for when the bridge would reopen.
“So what they’ve told us is that it’ll definitely be closed through the end of this week, possibly through the end of next week,” the mayor said.
DOT spokesman Kevin Israel said this week that repairs are “more extensive” than first thought. He was checking to confirm the accuracy of Mayor Lempert’s statements about the foundations.
The bridge was constructed in 1792, and is believed to be the oldest bridge in continuous use on a state highway in New Jersey and possibly the country, Mr. Kiser said. The DOT was not immediately able to say Monday when the bridge was last inspected.
Mayor Lempert explained what might have led to this round of problems with the old structure. She said that stretch of Route 206 had been mistakenly put on the state’s truck route map.
“Some of the damage that was being caused to the bridge was because you had vehicles coming over there that had no business being on top of that bridge, because the trucks were being directed there,” she said. “Now that’s been cleared up.”
Princeton has one other bridge that old, also built in 1792, on Mercer Road over the Stony Brook. Mr. Kiser said it was reconstructed by Mercer County in the late 1970s.
To fix the foundation problem, the state would need to pump in concrete. Based on Mr. Kiser’s experience, he said that kind of repair would take anywhere from a week and a half to two weeks or longer, weather permitting.
As for detours, the state has said motorists traveling south on Route 206 should go right on Georgetown Franklin Road (county Route 518) at Rocky Hill, left on Hopewell Princeton Road and right onto Route 206 south.
Northbound drivers should go left on Carter Road, right onto county Route 518 and left back on Route 206 north.
Also, Mr. Kiser said the state intends to replace a flood plane bridge that helps serve as one continuous crossing along with the historic bridge over the Stony Brook. He said the state wants to do the repairs and replacement all at once, rather than take a piecemeal approach.
