Axial strength of steel circular hollow section (CHS) X-joints strengthened by flanged larger pipe

In steel design, enhancing structural joints capacities is considered a challenge that faces the designer. Recent research related to strengthening T-joints by utilizing two outer hollow ring flanges welded to additional pipe showed that this technique can improve significantly joints strength. In this study, the utilization of this technique is extended for enhancing the axial strength of CHS X-joints. In this regard, a parametric study using finite element models was carried out to investigate the different design aspects that might affect the behavior of strengthened X-joints. The examined parameters included, the ring flanges diameter, the stiffening pipe thickness and length for different brace diameter-to-chord diameter ratios and chord diameter to double chord thickness ratio. The results demonstrated that these strengthened X-joints gained significant axial strength that reached up to three times the axial strength of the un-strengthened joints. Finally, an equation that estimates the axial strength of strengthened joints was established based on the achieved results.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author