Experimental and numerical fatigue assessment of duplex stainless-steel corrugated web I-girders

This paper investigates the fatigue behaviour of duplex stainless-steel (EN 1.4162) corrugated web beams. Thirteen beams, divided into two groups with different corrugation angles and radii, were tested under cyclic loading to failure. Additionally, one beam from each group was tested under static loading to estimate the hot spot stress (HSS) at the crack initiation location (S-point). The tests revealed two primary fatigue cracking modes: web cracking initiated at the web weld line within the shear span, and flange cracking initiated at the corrugation corners (S-points). A statistical evaluation of the developed flange cracks was conducted and compared with previously established detail categories (DC) for carbon steel using the nominal stress method. The tested beams exhibited fatigue strength comparable to carbon steel beams. Specifically, beams with a 45° corrugation angle corresponded to DC100, while beams with a ∼30° corrugation angle corresponded to DC125. The estimated hot spot stress obtained from test measurements was used to validate the FE model. The fatigue test results were then evaluated using the hot spot stress (HSS) and effective notch stress (ENS) methods. The HSS method with DC100 and the ENS method with DC225, according to IIW guidelines, both based on the maximum principal stress component, provided conservative estimates of the fatigue strength of the tested beams. • Fatigue testing of duplex EN1.4162 corrugated web beams. • Fatigue cracking modes at flange-to-web welded detail in corrugated web girders. • Fatigue strength comparison: carbon vs. duplex corrugated girders. • Analysis of fatigue test results with hot spot/effective notch stress methodologies.