Cracking of rc beam/column joints: implications for practical structural analysis and design

The work is concerned with an analytical investigation of the behaviour of reinforced-concrete beam–column joint subassemblages under monotonic and cyclic loading in an attempt to assess the effect of cracking suffered by the joint on the overall structural response. The behaviour of the structural forms investigated was established by nonlinear threedimensional finite-element analysis, after the latter had first been validated through a comparison of analytical predictions with published experimental findings. In all case studies
presented, the joints were found to suffer considerable cracking that initiated at early load stages and led to an increase of the overall displacement values by a factor larger than 2. Such behaviour indicates that the assumption of ‘rigid
joint’, which is implicit in methods used for the practical analysis of frames, is not applicable when such methods are employed for the analysis of concrete structures, even within the elastic range of structural behaviour.