This bridge has a two-span prestressed concrete box girder superstructure, end diaphragm abutments on large diameter piles, and a battered two column bent.
This bridge was recently retrofitted to survive a large earthquake (after this photo was taken). Since battered columns will take longitudinal displacement as an axial force, the columns must resist the earthquake with brute strength. Therefore, the reinforced concrete columns were encased in steel.
California Bridges - El Curtola Road Overcrossing by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.