The Pasadena City Hall, built in 1927, is an iconic landmark in Southern California. The 190,000 square foot structure sustained damage during the 1994 Northridge Earthquake and further studies found that the structure posed a significant safety hazard to its occupants in the event of a major earthquake. In order to repair the structure the City approved an $80 million seismic rehabilitation effort. Because the structure is on the National Register of Historic Places, changes to the appearance had to be minor and conventional retrofit methods could not be used (shear walls would negatively affect the appearance of the structure). Thus, the solution was the use of 240 friction pendulum isolators that de-couple the structure from the ground and allows it to move freely in the event of an earthquake. The isolation system was designed to withstand an 8.0 earthquake. In order to install the isolators, a new foundation was built and transfer beams were used to limit the number of isolators. The project was successfully completed in 2005.
Picture Source: https://upload.wikimedia.org/wikipedia/commons/d/de/Pasadena_City_Hall_at_dusk.jpg