Elongation of Plastic Hinges in Ductile RC Members: Model Development

Abstract

This paper describes the development of an analytical plastic hinge element that can predict flexural, axial, shear and elongation deformation in plastic hinges. The element consists of layers of longitudinal and diagonal springs that represent the behavior of concrete and reinforcement. These springs are modeled using nonlinear path-dependent cyclic stress-strain relationships of either concrete or reinforcing bars depending on their position in the cross section and also depending on the mechanisms they are representing. Through a preliminary scrutiny of the analytical results, in-depth qualitative and quantitative information on the causes and consequences of plastic hinge elongation are discussed. An extensive experimental verification of the plastic hinge element is presented in a companion paper.