After a chunk of concrete fell from the South Street Bridge late last week, the city has initiated random inspections of about ten bridges "of the same general type... and of the same general age" as the 80 year-old bridge according to Philadelphia's Chief Engineer and Surveyor Joe Syrnick.

Police closed the bridge at around 4 p.m. Thursday evening due to concrete falling onto Interstate 76 from the structure's sidewalk . Both westbound lanes of the Schuylkill Expressway were also blocked off.

Obligated by federal law to inspect the 350 bridges in its care every two years, the city chose to double-check those bridges similar to the South Street Bridge with inspections over the past three days.

The South Street Bridge itself is scheduled for reconstruction, though Syrnick said work on the project "probably won't start for another four or five years."

"This is by far the most complicated bridge project we've ever done, and by far the most expensive one we've ever done," Syrnick said, noting that the revitalization of the span could run into the $60 million range.

Syrnick explained that, between the sections over freight and passenger rail lines, the river and 76, the South Street Bridge is in fact "quite a series of bridges, all of which are going to be replaced."

Damage to the structure on Thursday was relatively minor -- "a hole... about the size of a cantaloupe" in the sidewalk, according to Syrnick. "We decided at that point that we should remove the whole bay, from the bracing to the bracing, just to be safe," he said.

City workers at the scene removed weak concrete around the hole, creating roughly a two foot by two foot gap which has been plated over. According to Syrnick, the concrete will likely be replaced some time in the next month.

"The roadway is fine, the entire bridge is fine, there was never any structural problem with the bridge in terms of the bridge falling down," Syrnick added. "In spite of what we all think, this sort of thing happens, it wasn't like, 'Oh my gosh, we'd never seen this kind of thing before.'"

Syrnick attributed the incident to "a combination of being very old... having a bad winter... and the recent intense wetness."

The University has been heavily involved in the planning of the reconstruction. Special attention has been paid to access to the Hollenback Center, home to Penn's Naval Reserve Officers Training Corps program.

The new bridge will also feature broadened sidewalks, creating a "promenade" over the river.