Nonuniform interface failure of steel-concrete composite structures bonded using epoxy resin mortar

摘要

The connection between steel and concrete determines the overall mechanical properties of the composite structure. Compared with the conventional method of connecting materials by using metal connectors, using an adhesive to connect steel-concrete composite structures is more advantageous. In this study, high-speed cameras and a conventional data acquisition system were used to perform a push-out test on steel-concrete composite structure specimens connected using epoxy resin mortar. The study obtained the failure mode, interface strength, and ductility index of the specimen. The results revealed that the failure modes of the specimens were damage in the concrete at the interface of the adhesive, indicating that the adhesive material has a good bond strength; with the improvement in the concrete strength grade, the limited load increases along with the strain, but the ductility decreases. In this paper, digital image correlation (DIC) technology was used to analyze the strain development of the concrete interface, and the results revealed that the strain distribution at the interface was nonuniform. Compared with the conventional strain gauge test method and elastic mechanics theory, the results of DIC measurement indicate that the DIC technology can reveal the nonuniform failure process and failure mechanism of the interface.