Viscous damping systems are often implemented in structures to reduce seismic damage. The stiffness of these elements is dominated by the most flexible part of the set including brace extender. auxiliary mounting elements and damping unit. Existing experimental data are used in this study to show that the actual stiffness of the set is about 25% to 50% of the value generally adopted i... https://www.nacrack.com/quick-sale-Graffiti-Chicago-Refection-Skyline-Canvas-super-sale/