SEATTLE - Seattle's Magnolia Bridge, which is used by thousands of people every day, is in a sorry state.
KIRO 7 Eyewitness News measured movement on the bridge and hired an expert who said the bridge should be replaced.
KIRO 7 reporter Graham Johnson found that the bridge is literally crumbling.
KIRO 7 knew the Magnolia Bridge was old, but a news crew was surprised to find chunks of concrete that had fallen from it.
The bridge is hardly state-of-the-art.
Parts of it shake from passing traffic, and KIRO 7 used seismograph apps on an iPad and an iPhone to see how vehicles moved the needle.
But to truly understand the bridge and its problems, it has to be seen through expert eyes.
Johnson drove the bridge with Stewart Gloyd, a retired bridge engineer.
“Basically, it still looks pretty vulnerable, a pretty fragile type of bridge,” said Gloyd. “It’s been through a lot, I can tell.”
Gloyd designed around 100 bridges over his career and reviewed plans for many more as chief bridge engineer for the state Department of Transportation.
He also served as an expert witness in lawsuits over the collapse of the I-35W Bridge in Minnesota, where 13 people died.
KIRO 7 hired Gloyd to look over the Magnolia Bridge.
“It’s even older than I am, which makes it really old,” said Gloyd.
The bridge was built in 1929 and was one of many projects at the time in a growing city.
The concrete truss design is unusual. There are only a few like it in the state.
“I’d say this is one of the most interesting old bridges that I’ve seen,” said Gloyd.
It wasn’t long into the visit that Johnson and Gloyd found something startling: Chunks of concrete beneath the bridge.
Gloyd said it looked like the pieces fell from the edge of the bridge, not the most critical area.
“But it can certainly lead to serious problems,” said Gloyd.
Chunks fall after moisture seeps into concrete and corrodes the steel reinforcement.
John Buswell oversees bridges for the Seattle Department of Transportation.
“Concrete falling off bridges is something we deal with on all of our concrete bridges,” said Buswell.
Buswell said he’s not aware of anyone getting hit by concrete falling from city bridges.
A net is installed beneath the Magnolia Bridge over an entrance to the Port of Seattle’s cruise ship terminal.
It appears to be there to catch concrete pieces, but the city has no record of who installed it or when.
As for what the falling chunks mean for the structural integrity of the Magnolia Bridge, Gloyd told KIRO 7 they are a sign of deterioration.
“The main concern would be the integrity of the roadway deck itself,” said Gloyd.
The city usually inspects bridges every two years, but because of its problems, the Magnolia Bridge is often inspected twice a year.
And every four hours, monitors on the bridge give city engineers data about the stress of critical spots.
KIRO 7’s visit with Gloyd revealed there’s a lot to watch.
“This asphalt overlay is getting worn out,” Gloyd showed Johnson.
The roadway is rough. The bottom of the bridge was moist enough to grow ferns, and on the side of the bridge, there’s more exposed steel.
“This could get a bit serious. If it continues, you can see the spalling here that's going to come off at some point,” Gloyd.
Salty marine air poses an ongoing threat.
“Most of the storms would be coming in from this direction and hitting the side of the bridge directly,” said Gloyd.
KIRO 7 reviewed city inspection records which rate the Magnolia Bridge as structurally deficient.
The city insists that does not mean the bridge is unsafe.
“The bridge is safe. If the bridge wasn't safe, it would be closed,” said Buswell with SDOT.
Definitions: Structurally deficient and sufficiency rating
Engineer Gloyd agreed.
“It’s like a car with bald tires, if you're aware of it and you take precautions you can get by with it,” said Gloyd.
Gloyd says he can’t estimate how much longer the bridge will last but says as bridges deteriorate over time, they become tougher to maintain.
“The life of a bridge boils down to how well you take care of it and whether bad things happen during its life,” said Gloyd.
Two really bad things have happened to the bridge. In 1997, a mudslide seriously damaged the support structure. Repairs closed the bridge for months.
Then in 2001, the Nisqually earthquake took out nearly half the horizontal braces. It cost $5 million to replace them with steel.
After all the retrofitting, the bridge is now a patchwork quilt of engineering designs.
“It’s unusual in my experience to see this much work done on a bridge just to keep it going,” said Gloyd.
Gloyd summed up the bridge’s condition like this:
“It’s still here, it's still doing the job, but it's pretty fragile looking overall and certainly it would be nice to retire it,” said Gloyd.
After the earthquake, the city started talking about replacing the Magnolia Bridge. Engineers held public meetings and did about 30 percent of the design work.
But with the replacement cost estimated at $300 million, there’s no timeline – because there’s no money.
Here's the problem: When you put the Magnolia Bridge into the formula for federal money, it doesn't rank very high.
Traffic counts are one reason.
The city estimates a little more than 16,000 cars take the bridge every day.
Compare that to the Spokane Street Viaduct, which has four times the traffic.
And even though the bridge is the primary route to Magnolia, there are a couple other ways to reach the neighborhood.
City leaders said replacing the Magnolia Bridge is high on their wish list if they had the money.
They said it will likely take funding cobbled together from many places to finally replace an 84-year-old bridge that’s rumbling and crumbling.
Adding to the problems -- Seattle now has $1 billion maintenance backlog on bridges and other roadway structures.
And because the Magnolia Bridge is so vulnerable to earthquakes, the city is now exploring putting gates on the bridge to stop traffic immediately after an earthquake.
Note: Bridges with the lowest numbers have the most problems. Those with ratings of 100 are new.