Failure mechanisms and cracking performance of T-shaped SCC beam-column connections at top floor: Test results and FE modeling

In recent decades, self-compacting concrete (SCC) has gradually gained popularity based on its unique workability without any internal and external vibration. SCC development must ensure an acceptable level of balance between deformability and stability by following the characteristics of materials and the mix proportions. In the case of the structural performance of reinforced concrete (RC) structures throughout the earthquake, beam column connections behavior is one of the most common causes of failures. On the other hand, T-shaped beam-column connections on the top floor have a critical condition based on the different types of live loads. As an alternative, SCC with specific properties includes workability and resilience against segregation, which is a great solution to improving the behavior of RC connections in a seismic area. In this paper, experimentally and numerically, investigation of six T-shaped SCC beam-column connections through different reinforcing bars ratio (rho) are presented to better understand their behavior during the gravitational load like heavy snow, particularly in terms of failure mechanisms and cracking performance. In the experimental stage, firstly, the mechanical specifications of SCC have been examined in terms of slump flow, V funnel, J ring, and L box tests. Secondly, the load-displacement performance of T-shaped beam-column connections at the top floor has been reported in terms of bonding behavior, ductility, and energy dissipation capacity. The displacement ductility of the experimental results are decreased from 12.4 to 3.5 while the ratio of the reinforcing bars was increased from %15 to %66 of the balanced section, and the energy dissipations capacity was increased by increasing the reinforcing ratios until %56 of the balanced section then started to decrease. In the theoretical part of the study, a three-dimensional nonlinear finite element method (FEM) model (ABAQUS) was employed along with the load-deflection curves were reported to compare the experimental results with the numerical output. The test results demonstrate, employing SCC as a type of concrete that has enough workability in RC connections had successful fulfillment in terms of ductility, load-carrying capacity, and energy dissipation.