1951:  The first prestressed concrete bridge in California begins construction in Los Angeles.

Two giant prestressed concrete girders are hoisted across the Arroyo Seco flood channel in Arroyo Seco Park near the South Pasadena City limits to create a pedestrian-only bridge.

The project attracts nation-wide attention because the prestressed design is a radical departure from previous types of conventional concrete bridges, such as those recently completed across the new Hollywood, Ramona, and Santa Ana Freeways.

More information can be found in the March-April, 1951 issue of California Highways and Public Works.