The work presented herein sets out to study the behaviour of external beam-column joints with different reinforcement configurations that form part of existing RC structures and are often not been designed in accordance with current code provisions. The work is concerned with a numerical investigation of the behaviour of reinforced-concrete beam-column sub-assemblages under monotonic loading to assess the effect of crack-formation within the joint region on the overall response of the structural configurations considered. The behaviour of the latter specimens is investigated numerically using a nonlinear finite element analysis package (ADINA) which is capable of realistically accounting for the nonlinear behaviour of concrete and steel. The predictions of the numerical models developed are initially validated against published test data. The validated models are subsequently employed to provide insight into the mechanics underlying specimen behaviour as they approach their ultimate limit state. Each specimen is modelled twice, once with their joint region being modelled as a reinforced concrete member and then (a second time) with the joint region being assigned elastic properties. In most cases studies presented, the joints were found to suffer considerable cracking that initiated at early load stages. This led to an increase of the overall displacement values which was dependent however, on the configuration of the reinforcement provided. This indicates that the assumption of 'rigid joint', which is essentially implicit in methods used for the practical analysis of frames, is not always applicable when employed for the analysis of concrete structures.