Effects of beam bar anchorage on beam–column joint behaviour

Abstract

Reversed cyclic-load tests are carried out on full-scale reinforced concrete (RC) exterior beam–column joints, which are fabricated to simulate those in as-built RC framed buildings designed to BS 8110. Emphasis of the study is placed on the effects of the types of beam bar anchorage and location of laps in column reinforcement on the seismic behaviour and shear strength of RC exterior joints subjected to simulated earthquake load. The behaviour is investigated with different types of anchorage in beam reinforcement and laps in column bars at the lower zone of the column. It has been shown from the experiment that all the specimens have low ductility capacity and poor energy dissipation ability. The test results are compared with two preseismic design codes (BS 8110 and EC 2) and two seismic design codes (ACI-318 and NZS 3101). It is shown that the types of reinforcement anchorage in beams have significant effects on the shear capacity and hysteretic behaviour of exterior beam–column joints. Present codes of practice do not accurately predict the shear strength of the non-seismically detailed joints. It is indicated that ignoring the design of beam–column joints may lead to potential damage of RC framed buildings in an unexpected low to moderate earthquake.