Design of Reinforced Concrete Spandrel Beams

Torsional stiffness of a reinforced concrete spandrel beam is known to decrease drastically after cracking and to cause redistribution of moment between the spandrel beams and the floor beams in building frames. In this study, 10 T-shape specimens representing a floor beam framing monolithically into a spandrel beam were tested. Test results show that large angles of twist under constant torque can be obtained after cracking and that the limit design method is desirable for designing spandrel beams. In using the limit design concept a specified torsional stress is sufficient to ensure ductility and crack control. In addition, methods are suggested for the design of joint stirrups to prevent joint failure, stirrups in the floor beam to prevent shear failure, and negative steel in the floor beam.