Probabilistic Fracture Assessment in Partial-Joint-Penetration Welded Pull-Plate Experiments Representing Pre-Northridge Column Splice Details

This study examined the fracture behavior of pre-Northridge partial-joint-penetration (PJP) welded column splices through a combined experimental and computational program. A total of 65 monotonic tensile tests were performed on pull-plate specimens fabricated with weld metals, detailing, and procedures representative of pre-Northridge practice, with variations in weld penetration, flange configuration, plate width, preheating, and testing temperature. Ancillary tensile and Charpy V-notch (CVN) tests were conducted to characterize base and weld metal properties for fracture modeling. The experimental results revealed brittle fracture across most configurations, with fracture stresses substantially below net section capacities. Limited ductile initiation occasionally was observed in low-penetration details, but rupture invariably transitioned to brittle. Wider specimens and reduced temperatures amplified weakest-link effects, lowering fracture resistance, and unequal flange geometries and thermal cracks increased susceptibility to brittle failure. Existing approaches for estimating fracture probability were found to be conservative, whereas computational simulations using a probabilistic fracture mechanics framework that incorporated stress-constraint effects reproduced the observed fragilities with close agreement. Overall, the findings confirm the high vulnerability of pre-Northridge PJP splices to brittle fracture, and also highlight limitations associated with approximations in the constraint-correction methodology and differences between pull-plate specimens and full column splice behavior.