Numerical investigation of effective parameters on behavior of concrete-filled steel tubular gusset plate connections

Concrete-filled steel tubular (CFST) gusset plate connection is a commonly used method in which the plates are welded directly to the columns. Due to the importance of stress distribution and energy absorption capacity on the behavior of the mentioned connections, in the present study, numerical analysis of the behavior of these connections under different loadings has been investigated. The studied variables include the thickness of the gusset plate, the compressive strength of the concrete, the D/t (diameter to thickness) ratio of CFST, and the type of loading. The results show that although filling hollow tubular sections with concrete prevents the local buckling of the steel wall, the use of concrete with higher compressive strength does not always lead to increased load capacity and energy absorption, so that in many of the studied models, the energy absorption capacity decreases by 18% to 30%. On the other hand, the results showed that the diameter-to-thickness ratio has a significant effect on the energy absorption capacity of the simulated connections, so that with increasing this ratio, the energy absorption capacity has decreased in the range of 76% to 91%. Also, the loading condition is effective in the load-bearing capacity and the energy absorption of the structure. So that in the case of eccentric tension and in-plane bending, the energy absorption capacity is reduced by 53% and 86%, respectively, compared to axial tension loading.