This study used finite element analysis to model concrete-filled steel tube beams that were partially wrapped with carbon fiber reinforced polymer (CFRP) sheets. The objectives were to investigate how CFRP wrapping length and number of layers affected structural behavior. Models of square and circular cross-section beams were created and verified. The analysis found that beams wrapped along 50% of their length saw reduced capacity with additional CFRP layers due to delamination failures. Beams wrapped along 75-100% saw increased capacity with more CFRP layers up to their ultimate strengths. Circular beams saw better strength improvements than square beams when wrapped with 1-3 CFRP layers.

1. Finite Element Analysis of
Concrete-Filled Steel Tube
Beams Partially Wrapped with
CFRP sheet
Finite Element Analysis of
Concrete-Filled Steel Tube
Beams Partially Wrapped with
CFRP sheet
Ahmed W. Al-Zand , Wan Hamidon Wan
Badaruzzaman, Azrul A. Mutalib and Salam J. Hilo
Department of Civil and Structural Engineering
Faculty of Civil Engineering and Built Environment
National University of Malaysia (UKM)

2. INTRODUCTION
Concrete-Filled Steel Tube Members (CFST)

3. INTRODUCTION
Application of concrete-filled steel tube beams
Nakamura et al. 2002
Bridge of Shinkansen - Japan

4. INTRODUCTION
CFRP sheet-tensile strength

5. INTRODUCTION
Literature ReviewTao et al., [2007]
Sundarraja and Ganesh [2011]

6. OBJECTIVES
• Study the potential use of CFRP sheets for strengthening
the square and circular CFST flexural members
• Investigate the behavior of CFST beams which are
wrapped partially by CFRP sheets
• Establish the optimum CFRP wrapping length and no. of
layers could be used for strengthening action

7. FINITE ELEMENT ANALYSIS
A. Modelling of the CFST beams
Square Tube (91.5 x 91.5 x 3.6mm)
Circular Tube (107.4x 3.5mm)

8. FINITE ELEMENT ANALYSIS
B. Verification of the Finite Element Model

9. NUMERICAL ANALYSIS OF CFST BEAMS
STRENGTHENED BY CFRP SHEET

10. RESULTS AND DISCUSSION

11. CONCLUSION
•The proposed FE modelling is sufficient to implement the
behaviours of the CFST beams partially wrapped with
CFRP sheet.
•Beams wrapped along 50% of its length showed
decreasing of their ultimate moment capacities with
increasing layers of CFRP patch because of the
delamination failures was occurred.
•Beams wrapped along 75 & 100% of its length showed
increasing of their ultimate moment capacities with
increasing layers of CFRP patch, where they reached
their ultimate strength.

12. CONCLUSION
•No significant improvement was observed in the
ultimate moment capacity for square and circular CFST
beams when the CFRP wrapping length increased from
75 to 100%.
•The capacity of circular CFST beam showed better
improvement than the square beam when strengthened
by 1 & 3 CFRP layers, where it’s increased around 65 &
100% for circular beams compared to only 19 & 64% for
square beams, respectively.

13. Thanks for
your listening