Simulated seismic loading on reinforced concrete beam/column connections

Laboratory tests to investigate the seismic behaviour of five reinforced concrete external beamlcolumn connection specimens, by subjecting the beams to a series of slow load reversals, are described. The first three tests were undertaken as an extension of a static (non-seismic) test programme and were primarily carried out for the purposes of rig development. The two further test specimens contained additional links in the connection zone to make them representative of current seismic practice in the U.S.A. These two specimens were subjected to a series of slow load reversals specifically intended to simulate seismic effects.
With the first three specimens, complete destruction of the connection zone was achieved after only four or five cycles; the last two specimens withstood ten and twelve cycles respectively. One of these latter specimens failed due to the development of a plastic hinge at the beaml column junction, the other by plastic hinges forming in the column above and below the beam. Detailed information regarding the form of the reinforcement strain distributions developed during these tests is presented, data being obtained using reinforcement internally strain gauged with electric resistance strain gauges. Each specimen contained around 230 such gauges.