Oct. 29, 2009— -- The collapse of 2½ tons of metal on the San Francisco Bay Bridge may have done little more than frighten rush-hour drivers, but experts warned the accident could be a sign of things to come if there isn't more attention paid to the nation's bridges.
Investigators said the two metal rods and a 5,000-pound beam that came tumbling off the Bay Bridge Tuesday was likely caused by high winds. With only one minor injury reported, it was still a grim reminder of the Minnesota bridge collapse that killed 13 people two years ago.
The pieces that fell off had been recently installed -- on Labor Day weekend -- after workers repaired yet another problem on the Bay Bridge, which first opened in 1936.
"The Bay Bridge is another wake-up call," Andrew Herrmann, of the American Society of Civil Engineers, told "Good Morning America." "The condition of our bridges is serious at this point."
At the time of the I-35 collapse in Minnesota, the federal government had labeled the 40-year-old bridge structurally deficient.
Shortly after the 2007 accident, Minnesota Gov. Tim Pawlenty agreed that the words "structurally deficient" were themselves worrisome.
"I think it was a cause for concern. But the federal government uses the term 'structurally deficient' and 'functionally obsolete' for lower second categories," he said at the time. "There are 80,000 bridges in that category or so across the U.S."
But now, two years later, one out of four bridges are still structurally deficient. While the Minnesota collapse was blamed on a design flaw, experts have said that many bridge problems are often caused by a simple lack of maintenance.
The average bridge in the U.S. is 43 years old and designed to last 50 years.
"That life can go beyond 50 years, but we have to invest the money so that it can last longer," Herrmann said.
U.S. Rep. Oberstar: 'We Can't Risk Another Bridge Collapsing'
The American Society of Civil Engineers estimates that it would cost an estimated $17 billion a year to properly maintain the country's bridges, but $10 billion is spent currently.
"We rebuilt the bridge in Minnesota in 437 days," U.S. Rep. James Oberstar, D-Minn., chairman of the Committee on Transportation and Infrastructure, said. "We can't put this off. We can't risk another bridge collapsing."
Oberstar said he's having trouble getting support for his bill that to spend more money on infrastructure over six years.
In San Francisco, emergency workers have continued to battle high wind gusts as they work furiously to repair the fallen pieces.
There is no estimate yet of when the bridge might reopen.
The Associated Press reported that the span carries 280,000 commuters every day. The closure has jammed alternate routes and mass transit as people try to find a way around the bridge.
The Associated Press contributed to this story.