Numerical simulation of substandard beam-column joints with different failure mechanisms

Generating the nonlinear behavior of substandard beam-column joints is challenging. Difficulties arise even more in reproducing the contribution of different nonlinear mechanisms (and their mutual effects) on the global cyclic response. This paper deals with the advanced numerical modeling of substandard reinforced concrete (RC) beam-column joints designed with structural details and material properties non-conforming to current seismic codes. Refined numerical models developed in VecTor2 and ATENA Science finite element (FE) software are investigated in detail to identify the factors affecting the global and local joint response. Two different modeling strategies are closely compared with experimental results of joint subassemblies with different failure modes in terms of hysteric response, crack pattern and its development, and local deformations at the joint panel and framing members. The advantages-disadvantages, difficulties in implementing the numerical model and their capability to reproduce the experimental behavior are discussed in detail. The comparison against experimental results in terms of local and global response is useful to assess the accuracy of the proposed models and it provides details on their applicability.