New reduction factor for cracked square hollow section T-joints under axial loading

• Parametric study of cracked square hollow section (SHS) T-joints.
• New Finite element mesh generator validated using experimental results.
• Axial tensile loading at the brace end.
• New expressions for determining the reduction factor (FAR) are proposed.
• Crack area and the brace to chord width ratio affect strength of the SHS joints.

This paper proposes a new expression for determining the reduction factor (FAR) of cracked square hollow section (SHS) joints. The FAR when multiplied with the ultimate strength of uncracked SHS joints, gives the ultimate strength of cracked SHS joints. A completely new and robust finite element mesh generator is developed to generate models for cracked SHS welded joints. The newly developed automatic mesh generator is validated using the experimental results. Parametric study is carried out for SHS joints subjected to axial loading at the brace end. The results reveal that the crack area and the brace to chord width ratio (β) have a significant influence on the ultimate strength of the cracked SHS joints. It is observed that for a particular crack area, the variation of the FAR values is up to 3.29% for different values of β. The results also show that the FAR values calculated using the existing equation for circular hollow section (CHS) joints are conservative in nature with percentage difference of up to 22.67%.