Finite element analysis of axially loaded FRP-confined rectangular concrete columns

• A finite element model for the nonlinear analysis of FRP-confined concrete columns has been formulated based on authors’ developed advanced constitutive models.
• The obtained finite element results have been verified successfully against specimens with rectangular FRP-confined columns.
• With this developed finite element model, it is now possible to evaluate the non-uniform and anisotropic confinement effects of FRP-confined rectangular columns.

Fibre-reinforced polymer (FRP) offers an effective and convenient means to strengthen existing RC columns. However, classical mechanics could not have an accurate prediction of the lateral strain due to axial load, hence an assessment on the overall confinement effects of the FRP. The finite element (FE) method, on the other hand, can give a full picture of the stress and the strain developed at a typical cross-section from linear elastic to ultimate failure loads. In this paper, a finite element model for the nonlinear analysis of FRP-confined concrete columns is presented, in which concrete elements are formulated based on advanced constitutive models recently developed, and it is verified against specimens with rectangular sections from existing experimental studies. As a result, the non-uniform and anisotropic confinement effects within rectangular sections of different shapes are determined, and their significance on the overall behaviour of axially loaded concrete columns could be assessed.