Plastic Hinge Lengths of Normal and High-Strength Concrete in Flexure

Full-range analysis methods are becoming popular in design of reinforced concrete structures. These methods require a knowledge of the behaviour of plastic hinges up to advanced curvatures. Concrete sections characteristically soften beyond the plastic phase. To analyse a strain-softening structure, many researchers have used a finite hinge length. In this paper, existing formulae are re-examined and the effects of different variables on hinge length are discussed. Experimentally measured values are compared with the values predicted by using these formulae. It is shown that the upper and lower bounds suggested by the ACI committee 428 provide reliable estimates of hinge lengths for both normal and high-strength concrete flexural hinges up to 80 MPa.