Experimental and numerical evaluation of weld strengths in steel box columns under bending and combined forces

This study evaluates the strength of two types of corner welds, namely fillet and complete joint penetration (CJP) groove welds, under bending and perpendicular forces along the welds' longitudinal axis . These types of weld are critical in the construction of high-rise buildings using steel moment-resisting frames. In accordance with AISC 358–16, which mandates the use of CJP groove welds for connecting flange and web plates within zones spanning from 12 in. above to 12 in. below the beam flanges, this study employs both experimental tests and numerical simulation. The experiments involved subjecting sets of fillet and CJP groove welds to forces up to 1000 kN, representing the maximum capacity for both weld types based on strength criteria. The fillet welded specimen ruptured at the centerline of the weld at an approximate 45 degree angle , whereas the CJP groove welded specimen failed at the plate-to-weld connection. Both welded specimens ruptured at 1000 kN, but the CJP groove weld specimen experienced a 39 mm displacement while the fillet weld specimen experienced 21 mm displacement. Further investigations included validating numerical models in Abaqus , focusing on ultimate strength, stiffness, and rupture behavior. The findings indicate that both fillet and CJP groove welds satisfactorily meet the structural requirements of steel moment-resisting frames. • Fillet welded built-up steel box shaped columns can be a viable alternative to CJP groove welded counterparts in SMRFs. • Two different corner weld types in welded built-up steel box shaped columns were tested under bending and combined forces. • Finite element analysis was used to predict the ultimate strength, stiffness, and rupture behavior of the tested specimens. • The primary failure mode observed in the fillet welded built-up box shaped column was rupture along the weld centerline. • The primary failure mode observed in the CJP groove welded built-up steel box shaped column was rupture in the steel plate.