Experimental Study of Transversely Loaded Fillet Welds for Seismic Actions

The New Zealand Steel Structures Standard NZS3404 uses a simplified method to predict the design capacity of fillet welds and hence to size the weld. From current research into the performance of these fillet welds under transverse and longitudinal loading to failure, the current weld design provisions are likely to be conservative compared with those in overseas high seismically active countries of comparable technical capability in fabrication. This paper describes a research project to identify the actual capacity of the fillet welds, as the most common type of welds, by experimental cyclic testing, to propose more realistic design provisions for fillet welds in seismic resisting systems compared to those specified by NZS3404. This is a collaboration between AUT, UoA, HERA and the University of Michigan, with the aim of making the seismic fillet welds design and fabrication more cost-effective while ensuring the continuing adequate performance of these welds, particularly under severe seismic actions. The experimental cyclic testing is being conducted at AUT labs. These include fillet weld samples of different sizes being loaded cyclically in the elastic and post-elastic range using dynamic hydraulic actuators. This paper, which will have also been presented in the 2024 NZSEE Annual Conference, provides information about the test setup, specimens’ configurations, and cyclic loading regime along with the results and recommendations.