Influence of weld details on fracture behavior of connections using high-strength steel

Based on post-earthquake research, brittle fracture of steel structures typically occurs near connection weld seams. The study proposes a new welded structure to improve the fracture resistance of connections. The fracture toughness of steel may decrease with increases in steel strength, and thus the fracture behavior of connections using high strength steel (HSS) was studied. Local welded specimens with different design details were tested under quasi-static loads, a finite element model was established, and initial cracks were assumed to analyze the fracture behavior of three types of local welded structures. Based on fracture mechanics, mode I elastic stress intensity factor (K-l) and inelastic J-Hntegral (h(l)) at the crack tip were calculated to predict the failure modes of HSS connections with different local welded structures. The experimental results were consistent with the expected results predicted via fracture mechanics, and the fracture of the specimen with the new design detail involving a backing strip welded at both sides occurred at a location away from the weld seam. The results indicated that the new design detail of local welded structure improves the fracture behavior of HSS connections. (C) 2018 Elsevier Ltd. All rights reserved.