The seismic behaviors of steel-concrete-steel composite walls with dumbbell-shaped connectors

In this study, quasi-static tests were conducted on six steel-concrete-steel composite wall (SCSCW) specimens with novel dumbbell-shaped connectors (DSCs) to investigate their seismic performance. The research parameters included the connector arrangement scheme and the axial load. The failure mode, load-displacement curve, and strain data were analyzed in detail. All the specimens exhibited flexural failure, and the experimental phenomena included the local buckling of external steel plates and compressive failure of internal concrete. The local buckling located between the foundation and first row of connectors, had a limited effect on the bearing capacity of the specimens. The connectors effectively controlled the buckling range of the external steel plates. With increasing axial load, the deformation capacity of the specimens decreased significantly. Under the same displacement, the greater the axial load, the greater the secant stiffness, and the higher the accumulated energy dissipation value. When the load reached its peak value, the yield range of the bottom front steel plates of specimen with large axial load was less than that of the specimen with small axial load. The theoretical formula accurately calculated the flexural bearing capacity of SCSCWs, and the maximum error and the average ratio which was defined as experimental value to calculated value were 9% and 1.02, respectively. The horizontal load-displacement relationship of the specimens was calculated using the OpenSees software, and the maximum error of the bearing capacity was 4%. The parametric analysis showed that increasing the steel plate thickness can effectively improve the bearing capacity of SCSCWs.