Reinforced/pre-stressed (RC/PC) concrete is one of the most commonly used
construction materials. This composite material demonstrates a highly non-linear
behaviour caused by, cracking, crushing, aggregate interlock, bond slip, dowel action,
shrinkage, creep, etc. Because the behaviour of reinforced/pre-stressed concrete
involves so many non-linear phenomena interacting with one other, the formulation of
rational analytical procedures to describe this behaviour is very difficult
Since the advent of the computer, powerful methods of analysis such as the finite
element method and stiffness matrix method have been implemented to study and
develop analytical solutions for the non-linear phenomena. However, the success of
such analysis depends on a thorough understanding and modeling of the composite
material behaviour.This study describes the development of a non-linear computer code used to predict the
non-liner response of reinforced/pre-stressed concrete beams that are subjected to a
combined axial force and bending moment The study discusses a new simplified
approach, whereby the non-linear response is captured via a series of sequentially linear
steps. The finite element approach with the stiffness matrix method were used to model
the beam element structure and generate its stiffness matrix.
A monotonic empirical model for the concrete's stress-strain curve has been
implemented to predict both ascending and descending parts of the curve. An idealized
bi-linear elasto-plastic in tension and compression model has been assumed for
reinforcing and pre-stressing steel
