Finite Element Analysis of Concrete Columns Confined with FRP Sheets

Abstract

A nonlinear finite element model is developed for the analysis of plain and reinforced concrete column confined by FRP sheets. The column sections chosen for the analysis are either circular or square in shape. The behavior of small and large scale FRP wrapped concrete columns under uni-axial compression is investigated using the developed model. The proposed FEA model is based on appropriate selection of elements, strength failure criteria and other parameters required for accurate analysis of concrete columns confined with FRP sheets. The model is validated with some published results on FEA and experimentation. A detail parametric study is done to quantify the effect of the thickness, stiffness and fiber orientation of the FRP sheets as well as unconfined concrete strength on confinement and stiffness of the strengthened columns using the proposed model. Based on the present analysis results, accurate stress distribution in concrete and FRP is also obtained which improves understanding of the confinement mechanism of the concrete columns.

Beam moment and shear force calculations using digital-camera experiments

“…Equation (6) is then adopted to find nodal rotations and lateral deflections of the element. Finally, equations (14), (10), and (13) are used to find the nodal moments and shear forces of each beam element. The calculated moment and shear force are normalized by the maximum moment at the beam center and the maximum shear force at the beam end as follows…”

“…To find beam moments and shear forces, each beam segment is defined as containing m nodal lateral deflections, and equation 6is adopted to find the rotations and lateral deflections at the two ends of the element. Finally, equations (14), (10), and (13) are used to find the nodal moments and shear forces of each beam segment. Figure 4 shows the beam moment and shear force diagrams using the finite element and proposed methods, where the horizontal axis of Figure 4 is the current horizontal coordinates of the deformed beam.…”

Structural behaviour of square RC columns confined with CFRP wraps

“…During the last decade, the use of FRP composites has been successfully promoted for external confinement of reinforced concrete (RC) columns all over the world. Several studies on the performance of FRP wrapped columns have been conducted, using both experimental and analytical approaches [1][2][3][4][5][6][7][8][9]. Such strengthening technique has proved to be very effective in enhancing their ductility and axial load capacity.…”

Failure modes for FRP wrapped cylindrical concrete columns

“…This has been shown experimentally as well as numerically. 2 However, almost all numerical studies of FRP-wrapped concrete columns assume rigidly bonded interfaces. Concrete and epoxy as well as epoxy and FRP are assumed to have perfectly compatible displacements at the interface.…”