Pfeiffer Canyon Bridge: The Agility of Steel Bridge Construction

Spanning the beautiful Pfeiffer Canyon on the Pacific Coast Highway Route-1, the original Pfeiffer Canyon Bridge was a concrete box girder bridge that served the Big Sur community and visitors for many years. A storm in January 2017 created a mudslide on the surrounding hillside that moved one of the bridge support columns causing the bridge to become unstable. The California Department of Transportation (Caltrans) quickly assessed the situation, and the bridge was closed to traffic. One week later, the bridge fully collapsed and was damaged beyond repair.

Pfeiffer Canyon Bridge, image courtesy of Nucor Corporation

Time was of the essence to restore functionality to this vital highway connection. The project timing was a top priority for Caltrans, and a compressed schedule drove many of the design decisions. Nucor received the order from the bridge fabricator for 800 tons of steel plate on a Friday and shipped the materials three days later. The new bridge was opened to public eight months after the original was condemned. According to Roads & Bridges, this process would have normally taken about eight years to complete.

Overall, this was a challenging project due to the constrained worksite over a canyon where temporary spans could not be utilized during construction. Steel was the ideal solution for this urgent repair project allowing for horizontal launching of the girders from one side of the span to the other. Temporary pipe supports were placed on each abutment and a temporary tower was constructed in the canyon around mid-span to control elevation for final placement. The bridge was assembled in sections away from the final supports and then incrementally rolled out into place using hydraulic jacks. This method significantly reduced the construction time while also minimizing disruption to the surrounding environment.

The new bridge was completed in October 2017 as a single-span steel plate girder bridge spanning 315 feet with three 14-foot deep I-girders. The elimination of the interior supports removed structural vulnerability to future landslide activity and will serve the Big Sur area for future generations.