Variable Friction Base Isolation Systems: Seismic Performance and Preliminary Design

ABSTRACT

Variable friction systems (VFS) have recently been proposed as potential alternatives to traditional friction base isolation devices. However, numerical and analytical studies have been limited to the case of VFS characterized by hysteresis with specific values of re-centering stiffness.

This paper derives generalized response equations for VFS with arbitrary hysteretic behavior and presents a design approach for such systems. An extensive numerical study is used to validate the design process and to illustrate key differences in the response of VFS as a function of the systems’ properties, providing some suggestions to select the optimal device for a given seismic demand.

KEYWORDS:

• Base Isolation
• Variable Friction
• Damping
• Nonlinear Time History
• Displacement-Based Design