San Francisco County, California Bridges: Alemany Interchange

December 1998 (37.7352 Degrees, -122.4094 Degrees) Alemany Interchange

South of the Central Freeway Viaduct, Highway 101 and 280 come together at the Alemany Maze (34 0070). This  complicated interchange is composed of short stiff piers, big strong piers, and tall flexible piers. An innovative retrofit was developed that used isolation to make the different substructure elements move together during the design earthquake. The stiff members had flexible isolators that allowed the superstructure to displace. The strong members used isolators to prevent the columns from damaging the weaker bent caps. The flexible members were free to move without causing damage to stiff or weak elements.

San Francisco County, California Bridges: Alemany Interchange by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.