Experimental Evaluation of Noncircular Reinforced Concrete Columns Strengthened with CFRP

This paper presents the results of an experimental investigation on the axial behavior of medium and large scale Reinforced Concrete (RC) columns of circular and non-circular cross-sections, which were strengthened with unidirectional Carbon Fiber Reinforced Polymer (CFRP) wraps. A test matrix was developed to investigate the effect of different variables, such as the geometry of the specimen cross-section (circular, square, and rectangular), the side aspect ratio, and the area aspect ratio. A total of 22 specimens were divided into six series of three specimens each and two series of two specimens each. The largest and smallest columns featured cross-sectional areas of 0.8 m2 (9 ft2) and 0.1 m2 (1 ft2), respectively. All the specimens were subjected to pure axial compressive loading. The experimental results are compared with available data on RC specimens with one minimum dimension of the cross-section of 300 mm (12 in.). This evaluation allowed confirming that among circular and non-circular specimens of the same cross-sectional area and FRP volumetric ratio, the level of confinement effectiveness decreases as the side aspect ratio increases. Additionally, size effect within specimens of circular cross-section does not appear to be significant; however, for the case of noncircular specimens, scatter and limitation of data-points does not allow at the present time to draw a definite conclusion. A new analytical method that allowed estimating the confining pressure in noncircular cross-sections from the transverse strains at the corners is proposed. The obtained confining pressures and experimental results from this study allowed calibrating a strength model, which was validated with the available experimental data in the literature. Finally, the predictions of this strength model were compared to the ones by the model of Lam and Teng yielding close agreement.

• Corporate Authors:

  American Concrete Institute (ACI)

  38800 Country Club Drive
  Farmington Hills, MI  United States  48331
• Authors:
  • Rocca, S
  • Galati, N
  • Nanni, A
• Publication Date: 2007

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; Photos; References; Tables;
• Pagination: 19p
• Monograph Title: Seismic Strengthening of Concrete Buildings using FRP Composites

Subject/Index Terms

• TRT Terms: Carbon fibers; Columns; Ductility; Earthquake resistant design; Fiber reinforced polymers; Reinforced concrete; Specimens
• Uncontrolled Terms: Confinement (Maintenance)
• Subject Areas: Bridges and other structures; Highways; Materials; I32: Concrete; I35: Miscellaneous Materials;

Filing Info

• Accession Number: 01142224
• Record Type: Publication
• Report/Paper Numbers: SP-258-3
• Files: TRIS
• Created Date: Oct 20 2009 7:41AM