How A City Bridge Is Safe On Top But Not Below

We here at PhillyClout spent part of Thanksgiving pondering how the 102-year-old Walnut Lane Bridge could be safe to drive on when parts of it are apparently falling off down below.  The answer: It's all about decoration. 

The city put out a news release -- you can read it after the jump -- Wednesday at 5:15 pm announcing that that the stretch of Forbidden Drive that runs under the bridge would be closed while inspections are under way next week. The city is concerned about architectural concrete, which according to this Wikipedia entry, is used for decoration and not stability.

Check out this 2008 newsletter from the Friends of the Wissahickon [page 8] about the bridge as it turned 100.


The Streets Department and the Department of Parks and Recreation have closed Forbidden Drive and the parallel paths that pass under the Walnut Lane Bridge. The decision was made following a recent inspection of Walnut Lane Bridge that indicates architectural concrete may be falling from the bridge. The Streets Department’s investigation has not identified any imminent structural issues, so the bridge will remain open. The closure will remain in effect pending additional inspections, planned for the week of November 29.

During the duration of the closure recreational users can still use Forbidden Drive from Lincoln Drive to the bridge or from Northwestern Ave to the bridge, but trail users will not be permitted to pass under the bridge. Those who are looking to travel “through” Forbidden Drive should seek alternate on-street routes, or consider accessing the street system at Bells Mill Road, Wises Mill Road, Green Lane, or Kitchens Lane.

The Streets Department and the Department of Parks and Recreation thanks the citizens in advance for their patience and cooperation during this closure.