Base Isolation Gets Its Day in Court

After the 1989 Loma Prieta earthquake, the 1905 U.S. Court of Appeals and Post Office Building in San Francisco was closed. The owner, General Services Administration Pacific Rim Region, decided to undertake a full-scale seismic upgrade of the building structure, along with its repair, renovation and expansion. Now under way and scheduled for completion by September 1995, the project will be the federal government's first and the world's largest seismic, or base, isolation retrofit project. Total estimated cost is $83 million, of which $24.4 million is for the seismic retrofit. Use of the friction pendulum base isolation system--a new approach developed in the U.S.--helped save $7.6 million and halved the time and labor required for bearing installation.