The Bank of California is a 1908 Greco-Roman style structure with a 22-storey tower, 312 ft (95 m), annexed in 1967. The historically listed structure has large glass windows behind a Corinthian colonnade, which were not possible to obstruct, making strengthening of the three walls infeasible.
The owner was facing large accelerations and displacements from near fault effects. The solution involved attaching the roof as a rigid diaphragm to the neighboring tower by installing eight high capacity friction damped struts at the roof, providing lateral support and resisting torsional movement.
Damper has degrees of freedom in three directions due to compatibility between buildings. The strut was required to provide essentially a rigid brace until plastically yielding at 337 Kips, with +/- 10 inch displacement.
The solution was DAMPTECHs Friction Brace Strut. No other damper could meet required Stiffness AND damping requirements.
– 8 Friction brace struts coupling the roof of the historical building with a reinforced floor at the 5th floor of the tower
– High capacity (337 Kips), with a +/- 10 inch required displacement.
– Reduces costs of retrofitting the tower by effectively providing an energy absorbing brace at the 5th floor
– Allows historical building to meet new seismic demands while respecting the architecture
– Prevents pounding between the new buildings