Studying on cracking of reinforced-concrete beam and column joints

The work is concerned with an analytical investigation of the behavior 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 behavior of the structural forms investigated was established by nonlinear three-dimensional 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 behavior 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 behavior.