Fatigue tests on steel–concrete–steel sandwich components and beams

In Bi-Steel steel–concrete–steel sandwich members, the friction welded bar–plate connections are subject to plate tension, bar tension and bar shear with associated bar bending. The relative magnitude of these force components depends on the beam geometry and the type of loading. The force components interact, so component fatigue tests were performed under single and combined loads, each with a sufficient number of stress ranges to enable stress vs. fatigue life (S/NS/N) curves and equations to be defined. Fatigue tests were also conducted on eighteen beams, and the experimental fatigue lives are compared with the values estimated by means of a proposed interaction equation based on the experimental S/NS/N equations derived from the component tests.