Structural evaluation of GFRP-confined reinforced concrete hollow columns

A. De Luca, F. Matta, A. Nanni, F. Nardone, G. P. Lignola, A. Prota

Research output: Contribution to conferencePaperpeer-review


Although hollow-core reinforced concrete (RC) bridge piers are frequently used in practice, no guidelines are available for the design of their upgrade. Also, literature on hollow columns is scarce. Recent studies confirmed that the failure of hollow columns is affected by premature bars buckling and concrete cover spalling. This paper discusses a pilot experimental investigation on full-scale RC hollow columns confined with glass FRP (GFRP) and subjected to pure axial load. Hollow column specimens were characterized by an overall length of 3.05 m [10 ft], cross-sectional dimensions of 508 mm by 737 mm [20 in by 29 in] and a wall thickness of 114 mm [4.5 in]. Three specimens were tested: one unstrengthened (benchmark) and two GFRP-jacketed with two different confining reinforcement ratios. The specimens were designed according to dated codes (i.e., prior to 1970) for gravity loads only. In particular, steel longitudinal bar area and steel tie spacing were designed following the ACI 318-63 code-mandated minimum amount of longitudinal reinforcement and minimum tie area at maximum spacing for solid elements. The objective of this study was to determine how the confinement by means of externally bonded FRP sheets impacts column performance. Specifically, the investigation aimed at characterizing: the confinement contribution in terms of axial strength and prevention of instability of longitudinal bars; and the sensitivity of any enhancement in performance to the confining reinforcement ratio. It is demonstrated that the FRP confinement contributes to an increase in deformability as a function of the confinement reinforcement ratio.

Original languageEnglish (US)
Number of pages6
StatePublished - 2009
Event2nd Asia-Pacific Conference on FRP in Structures, APFIS 2009 - Seoul, Korea, Republic of
Duration: Dec 9 2009Dec 11 2009


Conference2nd Asia-Pacific Conference on FRP in Structures, APFIS 2009
Country/TerritoryKorea, Republic of


  • Confinement
  • Deformability
  • FRP laminates
  • RC hollow-core columns
  • Strengthening

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Civil and Structural Engineering
  • Building and Construction


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