Analysis of rectangular hybrid steel-GFRP reinforced concrete beam columns

Rafic G. El-Helou, Riyad S. Aboutaha

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


In this study, nominal moment-axial load interaction diagrams, moment-curvature relationships, and ductility of rectangular hybrid beam-column concrete sections are analyzed using the modified Hognestad concrete model. The hybrid columns are primarily reinforced with steel bars with additional Glass Fiber Reinforced Polymer (GFRP) control bars. Parameters investigated include amount, pattern, location, and material properties of concrete, steel, and GFRP. The study was implemented using a user defined comprehensive MATLAB® simulation model to find an efficient hybrid section design maximizing strength and ductility. Generating lower bond stresses than steel bars at the concrete interface, auxiliary GFRP bars minimize damage in the concrete core of beam-column sections. Their usage prevents excessive yielding of the core longitudinal bars during frequent moderate cyclic deformations, which leads to significant damage in the foundations of bridges or beam-column spliced sections where repair is difficult and expensive. Analytical results from this study shows that hybrid steel-GFRP composite concrete sections where GFRP is used as auxiliary bars show adequate ductility with a significant increase in strength. Results also compare different design parameters reaching a number of design recommendations for the proposed hybrid section.

Original languageEnglish (US)
Pages (from-to)245-260
Number of pages16
JournalComputers and Concrete
Issue number2
StatePublished - Aug 1 2015


  • Beam-column
  • Ductility
  • GFRP
  • Interaction diagram
  • Moment-curvature

ASJC Scopus subject areas

  • Computational Mechanics


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