John Beale, Post-Gazette The 31st Street Bridge walkway is closed, and wires are connected to the deck to offer support for the bridge railing.

If the Pennsylvania Department of Transportation closed every one of its bridges classified as "structurally deficient," there would be "chaos," according to PennDOT Secretary Allen Biehler.

		Online graphic See a chart that shows the number of problem bridges. Related coverage State has 20 more 'older' bridges

Statewide, 5,666 of 25,307 bridges (22.4 percent) fit into the structurally deficient category, a higher percentage than in all other states except Oklahoma (31 percent) and Rhode Island (26 percent).

Included in the category is the bridge that partially collapsed in Washington County on Tuesday, falling onto I-70 near its juncture with I-79 southbound.

By Federal Highway Administration standards, structurally deficient covers four classes of bridges, ranging from 4, or "poor," to 1, or "imminent failure."

Zero means a bridge is "beyond corrective action" and closed. A 9 is a bridge in "excellent condition."

Fifty-three PennDOT-owned bridges are rated as "0" and are closed. Another 743 are posted, meaning they carry weight restrictions because of fatigued or rusted metal, cracks, missing pieces, movement and other problems.

In southwestern Pennsylvania -- which includes Pittsburgh, "The City of Bridges" -- the situation gets worse.

In the 10-county region, 33.9 percent of the bridges are structurally deficient, more than two-and-a-half times the national average and higher than anywhere else in the state.

Don't despair, said Gary Hoffman, PennDOT deputy secretary for highway administration and a 33-year career civil engineer who helped develop the state's bridge inventory and management system in the 1980s.

"Even when my five grandboys are with me, I never consider whether or not to cross a bridge because I have confidence in the fact that we have a reasonable process in place" to repair or restrict crossings before they become unsafe, he said.

Mr. Biehler also claimed the public need not be alarmed, explaining how the department has a handle on the situation, even though the backlog of obsolete and deficient bridges has haunted PennDOT for decades.

"When we say a bridge is structurally deficient, it can mean a wide range of things, but it doesn't mean the public is in any imminent danger," he said.

Increased public concern about what's sometimes called a "bridge crisis" in Pennsylvania emerged last week, when a 60-ton concrete beam on the 45-year-old Lake View Drive overpass snapped and came crashing down onto I-70. Two vehicles were damaged and five people were slightly injured. The busy highway was closed for 30 hours.

Both Mr. Biehler and Mr. Hoffman characterized the bridge failure as "a rare occurrence" that, in essence, fell through PennDOT's safety net of checks and balances because the corrosion was concealed within the concrete beam.

Nevertheless, the incident sent engineers scurrying to identify other bridges of the same design, age and materials and to conduct further inspections to prevent a recurrence.

Besides state-owned bridges, about 7,100 structures 20 feet long or longer throughout the state are owned by municipalities, counties, the Pennsylvania Turnpike, and the Port Authority of Allegheny County.

Many of those also are classified as structurally deficient and in need of repair. They, too, must be inspected every two years in compliance with Federal Highway Administration regulations.

"If every bridge classified as structurally deficient were closed, no doubt about it, there would be chaos in our state," Mr. Biehler said. "That's why we use our different processes to evaluate them and, if need be, to weight-restrict them."

PennDOT spends more than $9 million a year just to inspect its thick portfolio of bridges.

"If [inspectors] find a problem, we don't hesitate [to close or post a bridge]," Mr. Hoffman said. "Public safety is the No. 1 consideration."

With so many major bridges on the list, playing catch-up is a major challenge and expense. For example, the 31st Street Bridge in Pittsburgh will cost $27 million for its first major rehabilitation since it was built in 1927-28.

Work is to start next month on the landmark span, which has been on the "structurally deficient" list for more than 10 years. It has remained open with no weight restriction during that time thanks to piecemeal repairs on the steel superstructure and jury-rigged repairs to the sidewalk railing.

PennDOT officials said the high percentage of structurally deficient and obsolete bridges is not the result of geographic or political neglect. They attributed the problem to a proportionately large number of bridges, many of them major and many spanning rivers and valleys, and to higher construction costs in an urban environment.

Last year, the department met its goal of bidding out $400 million in bridge construction and rehabilitation and $50 million in bridge preservation work, a total of $450 million, or about three times as much as 1997.

The goal for this year is to spend $500 million, an amount that Mr. Hoffman said PennDOT will have to spend each year for the next 20 years-- a total of $10 billion -- just to reduce the percentage of structurally deficient bridges to 10 percent, just below the national average and a manageable level.

PennDOT said it is making progress. The number of weight-restricted bridges has dropped to 743 from a high of more than 1,200 about five years ago. The number of closed bridges has gone from 75 to 53 today.

There are no closed bridges on the National Highway System, 5,400 miles of state-owned, major arterial roads criss-crossing Pennsylvania, including the interstates.

The progress is not enough to prompt Mr. Biehler to concede that PennDOT has turned the corner.

"Let's just say we've kept things from getting worse," he said. "We face a new challenge because a significant number of bridges in the 50-years-plus age bracket are coming due for major attention" and, like the 31st Street Bridge, those failing, fatigued bridges take plenty of money to repair, rehabilitate or replace.

Gov. Ed Rendell has named a nine-member Transportation Funding and Reform Commission to assess road, bridge and mass transit needs, identify cost-savings measures and recommend increased or new sources of revenue.

The commission's report is due at the end of the year.