D.Sc. (Tech.) Antti Ahola works as Post-Doctoral Researcher in the Laboratory of Steel Structures. His primary area of expertise is the fatigue strength of welded joints but he also works in different topics related to the joints and components made of steel and has active role in teaching. High-strength and ultra-high-strength steels are in the primary focus of the research. His research activities aims to find best practice for the fatigue design of welded structures and components, providing comprehensive understanding of fatigue failure mechanisms in welded joints and thus enabling accurate assessments of life cycle of structural components. In this context, the 4R method, including residual stresses, material strength, weld toe quality and load conditions as quantitative parameters, is the principal approach.