Experimental study on fatigue performance of composite beam with steel-plate-concrete composite decks

•A new type of composite deck was used in the composite beam.•The calculation method for stiffness of composite beam under fatigue loading was proposed.•The fatigue behavior of composite beam under positive and negative bending moment was tested and analyzed, respectively. In order to study the fatigue performance of composite beam with steel-plate-concrete composite deck under fatigue load, both static test on two specimens and fatigue test with constant-amplitude fatigue load on six specimens were conducted. The influence of the upper limit and lower limit of fatigue load as well as the amplitude of fatigue load on the failure mode and failure damage was studied both under sagging moment and hogging moment. In addition, for the tested specimens under fatigue load, the dynamic deflection, residual deflection, strains of concrete and steel plates, strain of steel beam, residual capacity and the flexural stiffness were recorded and analyzed. The experimental results demonstrated that the failure mode of specimens under sagging moment was the fracture of steel plate of composite beam, resulting in the concrete crush in compression region, however, the specimens under hogging moment developed good fatigue behavior with comparatively high bearing capacity and stiffness and no fatigue failure was found finally. The fatigue life was directly affected by the stress amplitude of fatigue load while the upper limit and lower limit of fatigue load had little influence on it. The conclusion obtained in the paper was helpful for the design of this type of composite beam.