Ductile Web Fracture Initiation in Steel Shear Links

Abstract

Tests conducted in the 1980s showed that well-detailed short shear links can exhibit stable and ductile cyclic behavior. Recent tests of prevailing A992 rolled shapes revealed that shear links designed according to current seismic specifications can fail by ductile fracture in the link web, a mode of failure that was not observed in earlier tests. This paper investigates the observed ductile fractures through computational structural simulation. An existing criterion for judging the propensity for ductile fracture initiation in steel is modified based on published tests results for notched bars to better pinpoint the location of ductile fracture initiation. Validated finite- element analyses of previously tested shear links are conducted and the results postprocessed to evaluate the potential for ductile fracture of specimens with several different types of details. Reasons for the occurrence of web fractures in new A992 steel beams as opposed to older links are discussed. An alternative stiffener configuration that mitigates ductile fracture and is at the same time practical to construct is proposed.