Placer County’s Foresthill Bridge will undergo a yearlong, $6.3 million inspection. Here’s why
The Foresthill Bridge will undergo ultrasonic testing to ensure its 282 welds are secure, Placer County officials announced this week.
“It’s iconic,” said Matt Randall, deputy director of the Placer County Department of Public Works, “so we want to make sure we do a good job with this.”
Randall said it’s customary for bridges throughout the country to get inspected regularly every year or two, though there was one case nearly 2,500 miles east that brought attention to the Foresthill Bridge.
The Jennings Randolph Bridge over the Ohio River, connecting Ohio and West Virginia, closed in December 2023 because it had cracking welds that required repair that took four months to complete.
That bridge had similar welds and was built with the same T-1 steel as the Foresthill Bridge, which led to officials’ decision to test the bridge as preventative maintenance.
The Federal Highway Administration issued a letter to Caltrans, Randall said, saying that any bridge that used T-1 steel and “butt welds” would require ultrasonic testing. The Foresthill Bridge is one of roughly 25 bridges throughout the state that will undergo a similar process.
According to the administration, ultrasonic testing is done by certified inspectors who use a single-element probe around welds to detect any flaws that might go unseen by the naked eye.
The Foresthill Bridge stands some 730 feet above the North Fork of the American River between Auburn and Foresthill in Placer County. It’s the highest bridge in the state and the fourth-highest in the country.
The testing will be done by what’s called a “snooper truck” that will drive on the bridge and use a large mechanical arm to allow inspectors to look at the structure underneath. One of the bridge’s four lanes is expected to be closed during inspections, though it’s not expected to cause congestion given the lack of traffic in the remote area.
“It shouldn’t be that much of an inconvenience for folks because it’s not like I-80 where you got tons and tons of traffic,” Randall said.
The project on the 51-year-old bridge was approved Tuesday and will cost $6.3 million. Eighty percent of its funding will come from the Federal Highway Bridge Program, and the remaining 20% will come from the state’s SB 1 Road Maintenance and Rehabilitation funds. It’s expected to take roughly a year to complete and will begin this summer.
About 25 people will work on the project, Randall said, including employees from the county, private consultants and Caltrans. Each weld will be double checked for quality assurance to make sure they are structurally sound.
“We have multiple people looking at these to make sure we don’t make any mistakes,” Randall said.
