Use of toggle brace system for the amplification of seismic damper motion in building structures

The use of viscous dampers for structures characterised by a relatively small deformability is somehow hampered by the small elongation of the dampers which reduce considerably their efficiency in the mitigation of the seismic action. This paper presents the results of an extensive parametric study which allows to determine the so-called Toggle Brace mechanical System which, for given geometric conditions imposed by the structure to which it is attached, allows to obtain the maximum amplification of the motion of the damper ends with respect to the inter-story drift. The results obtained indicate that it is possible to reach amplification factors up to 3 or 4 and that the best results are achieved when the two inextensible arms have similar inclinations with respect to the horizontal axis.