Experimental study on the behaviour of austenitic stainless steel and carbon steel welded shear connectors

Steel-concrete composite beams are commonly used in bridge construction. The corrosion of the supporting steel beams is known to be a cause of deterioration of composite bridges, while the shear connectors may also be at risk of corrosion from chlorides migrating through cracks in the concrete deck. Stainless steel composite beams offer a viable solution to the steel corrosion problem in harsh environments. However, their design is outside the scope of the current international design standards due to a lack of reliable experimental data. This paper investigates the structural behaviour of austenitic EN 1.4301 stainless steel and carbon steel shear studs welded to lean duplex EN 1.4162 I-section beams, focusing on the strength, ductility and the weld quality of the studs. Material tests were conducted on the studs and welded connection, with weld quality examined through X-ray computerised tomography (CT) scanning and etching. The paper also presents the results from eight push-out tests, assessing the shear stud resistance predicted by existing international design codes for steel-concrete composite construction. In particular, the European and U.S. bridge design codes were found to give safesided shear resistance predictions for the austenitic stainless steel studs welded onto lean duplex beams, which performed comparably to literature test results on carbon steel studs welded to carbon steel beams. However, the carbon steel studs could not be successfully stud welded to lean duplex stainless steel beams, thus their use is not recommended in lean duplex stainless steel composite beams. It is the authors' intention that the results presented herein will contribute to the development of the design rules for shear connectors needed for the European and U.S. design codes for duplex stainless steel composite bridges.