Buckling instability of web plastifying dampers: analytical and numerical approach

This paper describes a numerical study on the instability of a brace-type seismic damper based on the out of plane yielding of the web of wide-flange steel sections (Web Plastifying Damper, WPD)The damper is intended to be installed in a framed structure as a standard diagonal brace. Under lateral forces, the damper is subjected to high axial forces, therefore its buckling instability is a matter of concern. Several finite element models representing WPDs with different axial stiffness and various geometries of their components were developed and analyzed taking into account both material and geometrical nonlinearities. The influence of several parameters defining the WPD in the load-displacement curve was examined. Furthermore, a simplified model to predict the buckling load is proposed.