Shaking table tests of a yielding bracing system for strengthening non-seismically designed reinforced concrete frames

A yielding bracing system for retrofitting existing non-seismically designed reinforced concrete frames was assessed by testing 1/4 scale models of 4-storey by 2-bay plane frames on the EPSRC Earthquake Simulator at Bristol University, UK. The project involved the collaboration of researchers from the University of Basilicata-Potenza and Bristol University under the auspices of the European Consortium of Earthquake Shaking Tables (ECOEST) funded by the European Union under its Human Capital and Mobility Programme. The models were shaken with in-plane horizontal table motions that enveloped the Eurocode 8 acceleration response spectrum for soft ground. The yielding braces performed very well, enhancing the ductility of the r.c. frame and enabling it to withstand table accelerations of up to 0.94g with only minor cracking. With the braces removed, the r.c. frame suffered a second storey collapse that initiated at a peak table acceleration of 0.24g, clearly demonstrating the potential of the bracing system.