A new eccentricity-based simulation to generate ultimate confined interaction diagrams for circular concrete columns

Ahmed Abd El-Fattah, Hayder A. Rasheed*, Asad Esmaeily

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The analysis of circular concrete columns using unconfined concrete models is a well established practice. However, there is a necessity to develop realistic analysis and design tools that predict the extreme ultimate capacity of such columns since modern codes and standards like AASHTO LRFD are introducing extreme load events. The increase in strength and ductility due to full axial confinement is not applicable to pure bending and bending plus axial load simply because the area of effective confined concrete is reduced. The higher the eccentricity the smaller the compressed portion of the confined core. Accordingly, the ultimate confined strength is gradually reduced from the fully confined value fcc′ (at zero eccentricity) to the unconfined value fc′ (at infinite eccentricity) as a function of eccentricity to diameter ratio. A numerical analysis algorithm is developed using the finite layer procedure and the secant stiffness approach within a framework of incremental-iterative moment of area computations. The resulting nonlinear section analysis requires radial loading in which the eccentricity is kept constant or the axial load is proportional to the applied moment. The results are compared with existing experimental data and the widely used Mander model to benchmark the present predictions.

Original languageEnglish
Pages (from-to)1163-1176
Number of pages14
JournalJournal of the Franklin Institute
Issue number7
StatePublished - Sep 2011
Externally publishedYes

Bibliographical note

Funding Information:
This work was developed under a research project KSU 07-21 funded by the Kansas Department of Transportation . The encouragement and support of Kenneth Hurst and John Jones is highly acknowledged.


  • Circular columns
  • Confined concrete
  • Eccentric loading
  • Nonlinear analysis

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Signal Processing
  • Computer Networks and Communications
  • Applied Mathematics


Dive into the research topics of 'A new eccentricity-based simulation to generate ultimate confined interaction diagrams for circular concrete columns'. Together they form a unique fingerprint.

Cite this