Composite steel-concrete beams are used widely in bridge and building
construction as the main structural elements in flexure. These structures have a
design life and this may be reduced if loads are increased or environmental
degradation occurs. Strength of such structure members and thus replacement or
retrofitting may need to be considered. One method of retrofitting (stiffening and
strengthening) a composite steel-concrete beam is to externally post-tension the
beam. The present study focuses on evaluating the effect of adding the external
post-tension as a strengthening technique on the simple composite beams. The
study was conducted using the finite element program "ANSYS". Nonlinear
material models for the components of the composite beam were used in the finite
element model. The outcomes got from finite element analysis were confirmed
against available experimental results. A broad parametric study was conducted to
explore the effect of tendons profiles on flexural behaviour. This covers: load
deflection behaviour, converting the simple beam into partially continuous beam,
verifying an external post-tensioned simple beam.