The Pennsylvania Turnpike's Allegheny River Bridge debuted with little fanfare on Dec. 26, 1951.

The opening of a 67-mile turnpike section from Monroeville to the Ohio line drew only back-of-the-newspaper coverage from Pittsburgh's dailies, with not a mention of the 2,200-foot river span.

But on Tuesday, the bridge went out with a splash.

With dignitaries looking on from nearby Oakmont Country Club, the bridge's center sections were sliced apart in the blink of an eye by a rapid-fire series of explosions that rained an estimated 2,000 tons of steel onto the river and an island below.

"It's a proud day for the Pennsylvania Turnpike," said CEO Joe Brimmeier, who noted that by next year, the entire stretch from Ohio to beyond the Allegheny Tunnel, 125 miles, will have been rebuilt.

That includes the twin spans that will replace the demolished Allegheny River Bridge. Each will carry three lanes of traffic when the $193.6 million replacement project is completed in November. For now, one of the new spans is open to two-lane traffic in both directions.

State Sen. J. Barry Stout, who is retiring after four decades in Harrisburg and is known there as the "godfather of transportation," recalled one of his first public events: watching then-Gov. Milton Shapp preside at a dynamite blast that marked the start of Mon-Fayette Expressway construction.

"I've come full circle," he said. "Now I'm ending my career tearing something down."

Mr. Stout, D-Bentleyville, cut his speech a bit short, not wanting to be the first Pennsylvania senator to filibuster a bridge explosion. A few minutes later, police stopped traffic on the turnpike. At 10:09 a.m., crews detonated 200 pounds of explosives, sending a massive thunderclap through the valley.

When the smoke cleared, the bridge lay in ruins, another victim of Maryland-based Controlled Demolition Inc., the company that imploded Three Rivers Stadium and, more recently, the Davis Avenue Bridge on the North Side and a public housing high-rise in East Liberty.

"Everything went smoothly," Mr. Brimmeier said after conferring by phone with project managers. "We feel good about it."

A turnpike contractor had 24 hours to clear a passageway in the river and 48 hours to get all of the debris out of the water. It will take about two weeks to remove steel from the island and a causeway in the back channel.

Turnpike traffic was halted for about 22 minutes. The highway reopened after crews cleared a small amount of debris from the deck of the new bridge.

The end sections of the old bridge will be brought down with explosives later this month. For now, the turnpike is holding off on demolishing the bridge piers, while Allegheny County considers whether to preserve them for a future bike trail crossing.

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