Collapse of Curved Reinforced Concrete Beams

Analyses are presented for determining the collapse load of a beam curved in a circular arc and subtending a central angle less than 180°. The analyses are for the case of two concentrated loads placed at any point on the beam and are an extension of existing analyses that have been developed for single concentrated loads or distributed loads. The modes of failure considered are valid for beams with constant plastic moment and torque capacities at any section of the beam. In the case of reinforced concrete, the analyses are thus restricted to prismatic beams having constant reinforcement. Tests were conducted on four curved reinforced concrete beams and it was found that the plastic theory gave a satisfactory prediction of the mode of failure, i.e., location and type of plastic hinges. The predicted value of the ultimate load was conservative for modes of failure containing pure bending and combined bending-torsion hinges, and slightly higher for modes of failure containing free hinges.