The fatigue performance of composite dowels is of great significance, especially for a combination load case of shear and tension. However, this combination load case has not been accounted in the fatigue analysis of composite dowels so far. Therefore, this article presents both the experimental and theoretical studies of steel component's fatigue performance in composite dowels under the load combination. A fracture mechanics‐based theory of critical distance model was developed, and it was validated by a special designed fatigue experiment. The fatigue test rig was tilted and set with two hinges. By parametric numeric analysis, the steel teeth plate's thickness effect and tension effect on the fatigue behaviour were explored. The fatigue detail classifications of the joints are proposed as engineering design guidance based on EN 1993‐1‐9 and International Institute Welding provisions.