The Foresthill Bridge, the tallest in California and fourth highest in the U.S., stretches 2,428 feet across the American River canyon and carries more than 50,000 vehicles daily. Built in 1973 with T-1 steel, the bridge became the focus of a Federal Highway Administration (FHWA) and Caltrans initiative in 2024 to assess fracture-critical welds and guide national safety standards.
Placer County selected Â鶹TVÍøÕ¾ to perform non-destructive testing and documentation on all 288 butt welds. Using a combination of snooper trucks, custom scaffolding, and advanced ultrasonic methods, Â鶹TVÍøÕ¾ inspectors accessed welds more than 700 feet above the canyon while keeping the bridge open to traffic.
Initial results showed a defect rate much higher than the anticipated. Â鶹TVÍøÕ¾ quickly scaled operations, adapting inspection techniques for difficult locations, coordinating with Caltrans and FHWA oversight teams, and delivering real-time data to support timely repair decisions. Despite rain delays and challenging conditions, all work was completed in compliance with AWS D1.5 Bridge Welding Code and without safety incidents.
The findings from this project are already informing FHWA guidance for evaluating T-1 steel structures across the country. For Placer County, the work reinforced immediate safety, while nationally it advanced a proactive approach to bridge management.
In the numbers
288Ìý·É±ð±ô»å²õ
Inspected using advanced non-destructive testing methodsÌý
44 repairsÌý
Welds stabilized through targeted repairs and metallurgical review to ensure long-term safetyÌý
730 feetÌý
Maximum working height during inspectionsÌý
0 safety incidentsÌý
Maintained across months of elevated operations and weather-related delaysÌý
Learn More and See the Work in Action