How safe are
our bridges?

By William Kenny
Times Staff Writer

The fatal highway bridge collapse in Minnesota has drawn a lot of attention to structural conditions of bridges across the country, including Southeastern Pennsylvania.
But Northeast Philadelphia motorists hoping to plan their driving routes to avoid any structurally deficient bridges needn’t bother. According to data recently released by the Pennsylvania Department of Transportation, they’d never make it off their own blocks.
Of the 2,720 bridges 8 feet or longer in Southeastern Pennsylvania that are maintained by PennDOT, 602 of them, or 22 percent, are classified as structurally deficient, meaning they are in need of some repair.
Dozens of those deteriorating bridges are in the Northeast along thoroughfares such as Roosevelt Boulevard, Frankford Avenue, Cottman Avenue, Interstate 95 and Oxford Avenue. The bridges span creeks, railroads, other streets and open ground.
Though state transportation officials were appealing to other branches of government for additional bridge rehabilitation funding months before the Twin Cities disaster on Aug. 1, they insist that none of the area bridges listed as deficient and still in use is in imminent danger of a similar failure.
"We’re very conservative based on our inspections," said Gene Blaum, spokesman for PennDOT District 6-0, which administers the highway system in the five-county region. "If we think (a bridge’s condition) provides any impact to public safety, we’re going to close the bridge."
In 12 cases, PennDOT had done that. In addition, there are weight restrictions on 63 bridges due to structural decay. Statewide, nearly 6,000 of Pennsylvania’s 25,000 bridges made the deficient list.
Decay occurs as a result of stresses including weight, vibration, temperature variance and exposure to corrosive chemicals. The publicly released list of deficient bridges did not detail specific conditions at each location.
However, the state agency has also released detailed condition ratings for 54 steel deck truss bridges in the commonwealth that are similar in design to the failed bridge in Minnesota. Those bridges include 28 belonging to PennDOT and 26 owned by other agencies.
In Northeast Philadelphia, the 78-year-old Tacony-Palmyra Bridge is owned by the Burlington County Bridge Commission, while the 34-year-old Betsy Ross Bridge belongs to the Delaware River Port Authority.
Each bridge is rated in three key elements: the deck, superstructure and substructure. The deck is the top surface that carries traffic. The superstructure is the underlying or supporting part of a bridge underneath the deck. The substructure supports the superstructure and usually consists of piers or abutments anchoring the bridge to the earth.
Ratings are awarded on a scale of 0 to 9.
In the Tacony-Palmyra Bridge’s case, the deck has a "7" or "good" rating, while the super and sub structures are both rated "5" or "fair." The bridge sees about 50,000 vehicles a day.
According to Dave Lowdermilk, vice president of Pennoni Associates, the engineering firm hired by the Burlington commission to inspect and repair its bridges, recent work on the Tacony-Palmyra improved its deck rating from a "4" or "poor" to the current level.
Last year, the commission replaced the bearings that connect the deck to other elements of the bridge and help to absorb routine stresses.
The New Jersey Department of Transportation has yet to affirm the new 7 rating, so PennDOT still lists the deck as a 4.
Next year, Lowdermilk said, the Burlington commission plans to replace the steel "grid" decks on the two lift spans of the bridge and to make any needed repairs to structural elements underneath the grid decks. This should improve the bridge’s superstructure rating.
The work will be funded by the commission’s own capital budget and will not draw upon any federal or state funding on either side of the river, Lowdermilk said.
Also, the executive added, Pennoni and Drexel University have teamed on a new inspection program that will combine the academic engineering expertise of the school with the practical knowledge of the firm.
They plan to install sensors on the bridge that will give monitors perpetual data on the condition of the structure. This will enable faster information processing and analysis, Lowdermilk said.
Federal regulations require that bridges be inspected once every two years.
On the much newer and longer Betsy Ross Bridge, the ratings are 7 for the deck, 5 for the superstructure and 6 for the substructure.
According to John Matheussen, chief executive of the DRPA, the structural elements of the Betsy Ross have yet to reach their designed life span of 40 to 50 years. While the authority addresses "general" repair issues as they arise, no major rebuilds have been needed.
The bridge handles about 40,000 vehicles per weekday and 30,000 per day on weekends.
In addition to the biannual independent inspections mandated by the federal government, the authority has an in-house engineering staff with a chief engineer and maintenance crew for each of its bridges. The authority also owns the Ben Franklin, Walt Whitman and the Commodore Barry bridges.
With regard to the smaller state-owned street-level bridges, Blaum — the PennDOT spokesman — reported that the state agency has been granted a new funding source to repair deficient bridges.
In 2006, PennDOT spent $558 million on 894 bridge projects. A state transportation funding bill recently signed by Gov. Ed Rendell would provide an additional $532 million per year for 10 years for bridge and road repair through increased highway tolling and bond issues.
The funding package was in the works long before the Minnesota disaster, Blaum said. ••
Reporter William Kenny can be reached at 215-354-3031 or bkenny@phillynews.com