Collapse load analysis of yield-line elements

Yield-line elements are a new type of finite element formulated for the analysis of slabs in bending. Both the elastic and inelastic theories have been developed. However, this paper only describes the inelastic theory used to determine the collapse load of a slab. The theory proposed is an overshoot–return method which is both simple and stable. Yield-lines and plastic rotations are modelled by increasing the flexibility terms of the element. Johansen and Kempʹs yield criterion is also adapted to permit an analysis of both isotropic and orthotropic reinforcement. The element is verified by comparison tests with experimentation and Johansenʹs yield-line analysis which indicate that the theory is accurate and a viable design tool.