Influence of hysteretic dampers on the seismic response of reinforced concrete wide beam–column connections

This research investigates the seismic performance up to collapse, and the ultimate energy absorption capacity of, existing nonductile reinforced concrete frames with wide beam–column connections seismic upgraded with brace-type hysteretic dampers. Four 2/3 scale exterior and interior connections with and without brace dampers were constructed and tested in a shaking table. The hysteretic dampers were designed so as to increase the lateral stiffness of the connection by ten times, and to limit the maximum interstory drift below 0.7% of the story height. The test models were subjected to a series of seismic simulations of increasing peak ground acceleration until collapse. The brace dampers reduced the maximum interstory drifts by 60%–80%, and increased the ultimate energy dissipation capacity of the exterior and interior connections by 12 and 4 times respectively. The RC elements of the connections equipped with brace dampers remained in nearly elastic conditions (i.e. with minor damage) until one of the brace dampers failed.