Experimental study on mechanical properties of a new steel-concrete composite transfer beam

Experimental studies on the mechanical properties of a new type of steel-concrete composite transfer beam,the steel truss reinforced concrete (STRC) beam,were carried out. The new developed STRC beams were applied to a skyscraper in Guangzhou city. Two herringbone STRC composite transfer beams, one triangle STRC composite transfer beam and one normal reinforced concrete transfer beam were selected to test. Mechanical performances of the four specimens under vertical concentrated loads, including the characteristics of the strains of the reinforcing bars,stirrups and steel truss were studied. Meanwhile the mechanical properties of the new transfer beams and normal reinforced concrete transfer beam were compared. Results show that the width of the shear cracks is greatly decreased in the STRC beams,compared with that in normal concrete transfer beam with same size. The rigidity and bearing capacity of the transfer beams can be remarkably improved through adding steel truss in the concrete beams, even if longitudinal flexural reinforcements of the beams are decreased. The strains of the reinforcing steel bars and stirrups in the STRC composite transfer beams are much smaller than those in normal concrete beams under same load. As a type of new transfer member,the advantages of the concrete and the steel truss members are combined and high bearing capacity can be obtained, therefore,the STRC composite transfer beam is a safe and economic transfer beam with bright future of engineering applications.