Flatiron Completes San Gabriel River Bridge Hinge Project

Flatiron completed the Interstate 210 – San Gabriel River Bridge Hinge Replacement Project in December 2022. Flatiron was the prime contractor for the project that began in May 2022. The $17 million project is located in Los Angeles County on Interstate 210 in the city of Irwindale near Interstate 605.

This segment of I-210 is a conventional 12-lane, divided freeway with 12-foot lanes and 10-foot standard shoulders. The 800-foot span over the San Gabriel River is a major Los Angeles freeway system artery. Work included:

• Total demolition and replacement of four bridge hinges and railings
• Outside shoulder reconstruction
• Upgrade of concrete median
• Replacement of barrier rails, overhangs and storm drainage

Flatiron crews overcame several unique challenges with this project. The diversion of the San Gabriel River allowed temporary supports to be put in place before falsework began. More than 80 hydraulic jacks lifted the bridge, and the structure was cut in half (widthwise) to complete this repair. 

Workers protected the more than 1,400 bats of seven species from potential construction impacts by placing sound blankets and sound walls throughout the structure.

The new roadway meets 55-mph design standards and adds a 50-year lifespan to the existing structure.