• Jason Fischer

A polymer deck installed on the Morrison Bridge in 2011 and 2012 has proven so flawed since that Multnomah County has elected to scrap the whole $4.2 million effort—and replace it for a far higher cost.

For nearly a year, the Mercury's been writing about the worrying state of the Morrison—one of Portland's most trafficked spans. Shortly after the county outfitted the bridge in a new, somewhat experimental "fiber-reinforced polymer" the deck began cracking. Its panels started shifting. Screws came loose.

County officials maintain the Morrison is safe for traffic—though deteriorating— but announced today that an investigation has revealed the deck is beyond repair. Now, officials are hoping to divert state money dedicated to Burnside Bridge repairs into a $7.3 million replacement effort.

The irony? That replacement—slated for 2015— could be substantially similar to the steel grating the Morrison donned before county leaders elected to drape it in polymer. From the county's announcement:

The county is currently considering two options for the new lift span deck: an open steel grating similar to the original deck and a solid deck made of aluminum. The design for the new deck is scheduled to be completed later this year so that the deck can be replaced in 2015. Installation of the new deck will require lane closures and may also require several weekend bridge closures.

Since 2012, companies involved in the deck replacement project have been squabbling in court about who's to blame for the Morrison's troubles. The county jumped into that fray last year, pretty much blaming everyone. Tied up in the case: Conway Construction Company, a Washington-based contractor that carried out the work, Zellcomp Inc, which designed and marketed the decking system, and other suppliers and insurance companies who had their toes in the deal.

When the Morrison's deck was replaced, officials argued the existing steel grating was deteriorated, and proved slippery and dangerous during wet weather. When cars found their way from the bridge into the Willamette, this treacherous decking was sometimes blamed. So the county elected to go with the polymer—which officials praised as being lighter than steel, and offering better purchase for car tires—even though county engineers had had a difficult time with the same stuff on the Broadway Bridge.

That wasn't the only red flag. As the Mercury's reported, county engineers weren't aware of a 2009 study that suggested the polymer decking might be incompatible with a bridge like the Morrison. And county officials noticed cracks and other worrying signs in the polymer decking panels even before they were attached to the bridge. But rather than rejecting the materials, the county used them, merely demanding a discount.

Given all that, it's perhaps not surprising the Morrison began showing signs of deterioration almost immediately after reopening to traffic in 2012. Even so, today's announcement is a surprise. Most of the public discussion around repairing the bridge has centered on identifying and replacing only problematic panels. Now the county's saying that's not even possible.

"It's more than just installation that's involved," says Mike Pullen, a county spokesman. "There's issues with both installation and the material itself."

It doesn't help that the only company that currently makes FRP bridge decking is Zellcomp, which the county has sued, demanding its money back.

According to Pullen, the county's eager to get a move on designing and installing a new deck. In order to begin, officials need to ink a intergovernmental agreement with the Oregon Department of Transportation, diverting part of nearly $30 million that had been set aside to fix the Burnside Bridge. The county hopes design can commence by the end of the summer, so that a new deck—hopefully a robust one—can be installed beginning next year.

"The prudent thing is to start now," Pullen says.

Whenever work begins, it's bound to be a headache for motorists. The Morrison is the most-traversed of Portland's six county-owned bridges, carrying an estimated 50,000 vehicles every day.