STRENGTH OF CONCRETE-ENCASED STEEL BEAMS

Tests were carried out on 22 push-out specimens, five small-scale and two full-scale composite T-beams. The specimens consisted of steel sections encased in concrete. Variations were made in the degree of encasement for the steel section, the type of concrete, the reinforcement for the encasement and the size of the steel section. The behavior of the beams depended on the load for bond failure. The results for the fully encased beams showed that proper proportioining can ensure a bond failure load close to the theoretical ultimate capacity for full composite action. In contrast, the results for the partially encased beams showed that composite action could not be relied on for design purposes. Based on the results for the push-out specimens a procedure is proposed for predicting the behavior up to collapse of an encased beam. /Author/