Behavior of timber-concrete composite beams with two types of steel dowel connectors

Abstract

In this work the strength and the stiffness (EI) of wood-concrete composite beams with cross section T for two types of connection (bonded with epoxy and fixed by pre-drilling without adhesive) made by steel dowels, with 12.5 mm of diameter were analyzed. The beams were analyzed theoretically based on the Mohler model, which is available in the Eurocode 5 standard, and experimentally by bending tests with load applied in the thirds of the beam. To make the composite beams Eucalyptus citriodora wood and medium strength armed concrete slab were used. The slip modulus K and the ultimate strength values of each type of connector were obtained by direct shear tests performed directly on composite specimens. The results achieved showed that the connector bonded with epoxy adhesive provided a better strength and stiffness (EI) for the composite beams when compared to the connector fixed only by pre-drilling. The differences observed were up to 10% in this case. On the other hand, the strength and stiffness (EI) values obtained theoretically by the Mohler model were lower than the values obtained experimentally from the bending tests, and the differences being up to 25% in this case.