Analyses of plastic hinge regions in reinforced concrete beams under monotonic loading

Due to the high complexity and difficulty involved, the behavior of plastic hinge of reinforced concrete members has been previously investigated experimentally. This work investigates the plastic hinge analytically, using the finite element method. Lengths in the plastic hinge region involving rebar yielding zone, concrete crushing zone and curvature localization zone are studied systematically, under different parameters. The results show that none of the existing empirical models is adequate for prediction of plastic hinge length. As high non-linearity occurs in plastic hinge zones, the phenomenon of chaos is observed, for the first time, in flexural response of reinforced concrete structures.