BEAM MADE OF REINFORCED CONCRETE AT THE ENDS AND STEEL SKELETON AT THE MIDDLE

PURPOSE: To eliminate concentration of bending stresses of a joint part, by widening the flange axes at the ends of a steel skeleton beam and providing bearing plates, joining grooves, etc., and binding the ends of main reinforcements of the concrete column side joined with the beam, with band plates. CONSTITUTION: The end of the flange 4 of a beam 3 made of I-shaped steel is formed slant and wide and the ends of web 8 are cut to form joining grooves 9. This beam 3 is welded with the main reinforcements 5 extended from a reinforced concrete column, at the external sides of the upper and lower flanges and the ends of main reinforcements are bound by band plates 7. A bearing plate 10 and auxiliary plates 11 are protruded at the boundary of the concrete part, in the beam 3 and also stirrups are arranged on the main reinforcements 5 and then concrete is placed to unify them. The structure is designed so that the bending stresses and shearing stresses are transferred smoothly from the beam 3 to the concrete part 2, at the front end of the beam 3 and the front end of the concrete part 2, where stresses are concentrated.