One year ago, Congress defunded public media. Now that we're 100% community funded, please become a sustaining member or increase your existing membership today.
This archival content was originally written for and published on KPCC.org. Keep in mind that links and images may no longer work — and references may be outdated.
How safe are California's bridges?
Caltrans Senior Bridge Engineer Bing Wu inspects the underbelly of a bridge that's part of Pacific Coast Highway in Manhattan Beach.
(
Maya Sugarman/KPCC
)
Caltrans spokesman Jim Drago says a good bridge design is functional and doesn't overwhelm the surrounding environment.
(
Maya Sugarman/KPCC
)
Each bridge in Southern California has an identification number associated with it. Before an inspection, Wu prints out the history of the bridge's previous inspections.
(
Maya Sugarman/KPCC
)
Senior Bridge Engineer Bing Wu uses a hammer to inspect a crack in the bridge's asphalt. Then he measures how long and deep the hole is.
(
Maya Sugarman/KPCC
)
"We look like a doctor looking at a patient," says Bing Wu.
(
Maya Sugarman/KPCC
)
Drago and Wu write down which issues came to their attention, and measurements of cracks or other problems.
(
Maya Sugarman/KPCC
)
Wu spray paints circles around small chips in the concrete railing on the Manhattan Beach bridge, to mark them for future repairs.
(
Maya Sugarman/KPCC
)
Jim Drago and Bing Wu inspect the bottom of the concrete structure. The bridge was widened in 1972.
(
Maya Sugarman/KPCC
)
"It's older than I am," says Bing Wu of the bridge, which was built in 1930. The overpass is a typical concrete structure with metal beams.
(
Maya Sugarman/KPCC
)
Caltrans' Bing Wu first checks the top of the bridge, including the railing and the road.
(
Maya Sugarman/KPCC
)
Listen
4:24
How safe are California's bridges?
When a bridge fell in Washington last month it rekindled questions about the state of our nation's infrastructure.
That span over the Skagit river had been rated both "functionally obsolete" and "fracture critical" prior to collapse. Right now in California there are more than 600 bridges labeled either functionally obsolete, fracture critical or "structurally deficient."
MAP: Click here for an interactive map of Southern California bridges and their various ratings.
Those terms sound scary, but many experts say there's no need to worry.
"The terms functionally obsolete and structurally deficient do not really indicate the condition of the bridge," said Caltrans spokesman Jim Drago.
These are general terms, he explained, used by the federal government as part of a national bridge rating system.
FAQ: How do you know if a bridge is safe?
Sponsored message
The structurally deficient rating means that a bridge has a physical flaw of some kind. That could be something serious, but in most cases it's just cracked pavement or peeling paint.
Functionally obsolete means a bridge isn't up to current building standards. That often means the lanes are narrow or there is no shoulder for stalled cars. Sometimes it denotes a more serious structural issue that will force Caltrans to repair or rebuild a structure.
Fracture critical means a bridge doesn't have a secondary support system to stop it from collapsing if it is seriously overloaded, or if it experiences a significant accident that impacts a vulnerable section. Both the bridge in Washington state and the one that fell in Minnesota in 2007 were rated fracture critical.
"This kind of accident is always [a] very small probability thing," said UCLA structural engineering professor Jian Zhang. She maintains these circumstance are very rare, and that a fracture critical label does not necessarily mean a bridge is structurally unsound.
Fot its part, Caltrans says it shuts down any bridge that's deemed unsafe.
The agency recognized that the ominous-sounding federal classifications don't show the true quality of a bridge. So the state developed its own rating system, called the Bridge Health Index.
Rather than giving a general sense of how a bridge is doing, like the federal system does, the Bridge Health Index drills down into specifics. It includes inspection of more than 100 components of a structure, from the columns to the girders to the guard rails. Using this system, Caltrans can not only understand how sturdy a bridge is, but which parts might need work or replacement.
Sponsored message
Next year, the federal government plans to enact a similar system.
Still, not everyone is satisfied with this, or with any visual inspection method.
Barry LePatner is a construction lawyer and author of the book Too Big to Fall: America's Failing Infrastructure and the Way Forward. He says the eyes can't see everything happening with a bridge.
"There could be a huge crack on the inside of a multi-ton structural member, except it hasn't become visual yet for three more years," LePatner argued.
In the future he would like to see bridges fitted with sensors that can detect structural problems long before they appear. In fact, some bridges in California already use this kind of system, like the Vincent Thomas Bridge in Long Beach.
For the most part, though, states still rely on human inspectors to gauge the health of a bridge.
One year ago, Congress voted to defund public media, eliminating a critical $1.7 million from our budget every year going forward. But they couldn’t silence us, and we’re not going anywhere. LAist is now 100% community funded and that means we’re taking our future into our own hands and turning to you to keep local reporting strong.
You come to LAist because you want independent reporting and trustworthy local information. Our nonprofit newsroom doesn’t answer to shareholders looking to turn a profit. Instead, we answer to you and our communities. We are free to follow facts wherever they lead and to hold power to account without fear or favor. Our only loyalty is to our readers and listeners and our mission: to inform, engage, and strengthen Southern California’s communities.
If this story helped you, please become a monthly member today to help sustain this mission. It just takes 1 minute to donate below.
You come to LAist because you want independent reporting and trustworthy local information. Our nonprofit newsroom doesn’t answer to shareholders looking to turn a profit. Instead, we answer to you and our communities. We are free to follow facts wherever they lead and to hold power to account without fear or favor. Our only loyalty is to our readers and listeners and our mission: to inform, engage, and strengthen Southern California’s communities.
If this story helped you, please become a monthly member today to help sustain this mission. It just takes 1 minute to donate below.
Senior Vice President News, Editor in Chief
