ABSTRACT
The standard Bouc-Wen model results from the parallel combination of an elastic component and an elastic-perfectly plastic component. The force output F of the model is
ku F zy+p ( )p− (1)
where u is the deformation across the model, Fy the yield force, k the elastic stiffness, p the post-yield stiffness ratio, and z a dimensionless hysteretic parameter governed by
z k F
u z y
n = ( )⎡⎣ ⎤⎦1 uz + (2)
1 INTRODUCTION
The European seismic code EC8 (2004) covers conventional lateral-load resisting systems, such as steel Moment-Resisting Frames (MRFs), designed to experience inelastic deformations in main structural members (beams, columns or braces) under strong earthquakes. These inelastic deformations result in difficult-to-repair damage and downtime during which the building is repaired and cannot be used or occupied. To overcome these problems, an alternative seismic design strategy that concentrates damage in removable steel yielding devices and protects the rest of the structural system from yielding is highlighted. This design strategy is further enhanced by using viscous dampers in parallel to the steel yielding devices.
