McLean & Schultz: Structural Engineering & Architecture

The bridge, constructed in 1909, currently carries four lanes of vehicular traffic and two sidewalks over MetroLink and Southern Pacific Railroad and the Los Angeles River.

The North Broadway Viaduct was designed to resist gravity loads.  The arch geometry minimizes the presence of flexure in the ribs and, therefore, minimizes the amount of reinforcement needed.  The design does not include any capacity to resist the horizontal loads associated with seismic events.  The combination of the Viaduct's age, a framing system designed specifically for gravity loads, and the absence of reinforcing to develop ductile behavior, would result in a brittle failure during a major seismic event.
North Broadway Viaduct