The Donora-Monessen Bridge -- or the Monessen-Donora Bridge, depending on which side you live on -- could be nicknamed "Patches."

That's because the concrete deck of the key travel link in the Mid-Mon Valley is riddled with splotches of asphalt used to fill holes despite more than $2 million worth of slab and spot repairs made in 2001.

"That was a Band-Aid," said Don Herbert, bridge engineer for Pennsylvania Department of Transportation District 12. "It improved the ride but by no means did it accomplish what we wanted," mainly because the state had a limited amount of money to spend at the time.

With an infusion of state funds from last summer's transportation legislation, PennDOT is now prepared to do more comprehensive work, including replacing the entire four-lane deck of the Monongahela River span. The bridge is part of the National Highway System, so the federal government will pay 80 percent of the cost of the estimated $25 million rehabilitation.

Bids are to be sought in December, and the contractor is expected to be given a "notice to proceed" in February, triggering the start of two years of work. Because the schedule has been divided into phases, one lane of traffic will be maintained in each direction on the span that has grown in importance as an access to Interstate 70, shopping outlets around the Route 201 interchange in Rostraver and the MIDA industrial park in Donora.

"I liken the project to replacing the roof on your house because the deck is the main focus," Mr. Herbert said. "While we're at it, we're going to fix some rafters," or steel superstructure.

In 2010, the steel will be sand-blasted and painted with three coats, starting with primer. Local municipalities and schools may be asked to weigh in on the final color.

The deteriorated deck and old expansion dams have been leaking water onto the steel superstructure below. Damage from road salt used to clear the bridge in winter has been pronounced, accelerating rust.

The conditions are of special concern to PennDOT because the bridge consists of trusses, welded plate girders and "gusset" connectors similar to the I-35W bridge in Minneapolis that collapsed and killed 13 people last year.

Engineers made an emergency inspection of the bridge in August in the aftermath of the collapse. While the bridge was deemed structurally sufficient, they nevertheless wanted to expedite the upcoming rehabilitation.

"There was nothing we didn't already know," Mr. Herbert said. "None of the problems was serious. But the bridge does not have a lot of redundancy built into it. This work will make sure it remains in good shape."

The 2,111-foot-long bridge was opened in 1972 between Route 906 on one side and Route 837 on the other side. For those on the Monessen/Westmoreland County side, it's usually called the Monessen-Donora Bridge. For those on the Donora/Washington County side, it's the Donora-Monessen Bridge.

About 20 years passed before PennDOT carved out the 1.5-mile-long Vance DeiCas Highway in Rostraver to connect the bridge to Route 201 and I-70.

In addition to a new deck, the renovation project will include a variety of repairs and strengthening measures to the superstructure and the substructure.

The northbound lanes will be reconstructed first, while traffic is maintained on the southbound side. Then the southbound lanes will be redone. Temporary traffic signals will be installed for both phases to provide for the temporary traffic patterns.