Techno Press
Techno Press

Steel and Composite Structures   Volume 22, Number 3, October30 2016, pages 497-520
DOI: http://dx.doi.org/10.12989/scs.2016.22.3.497
 
Confined concrete model of circular, elliptical and octagonal CFST short columns
Vipulkumar I. Patel, Brian Uy, Prajwal K.A. and Farhad Aslani

 
Abstract     [Full Text]
    The confined concrete stress-strain curves utilised in computational models of concrete-filled steel tubular (CFST) columns can have a significant influence on the accuracy of the predicted behaviour. A generic model is proposed for predicting the stress-strain behaviour of confined concrete in short circular, elliptical and octagonal CFST columns subjected to axial compression. The finite element (FE) analysis is carried out to simulate the concrete confining pressure in short circular, elliptical and octagonal CFST columns. The concrete confining pressure relies on the geometric and material parameters of CFST columns. The post-peak behaviour of the concrete stressstrain curve is determined using independent existing experimental results. The strength reduction factor is derived for predicting the descending part of the confined concrete behaviour. The fibre element model is developed for the analysis of circular, elliptical and octagonal CFST short columns under axial loading. The FE model and fibre element model accounting for the proposed concrete confined model is verified by comparing the computed results with experimental results. The ultimate axial strengths and complete axial load-strain curves obtained from the FE model and fibre element model agree reasonably well with experimental results. Parametric studies have been carried out to examine the effects of important parameters on the compressive behaviour of short circular, elliptical and octagonal CFST columns. The design model proposed by Liang and Fragomeni (2009) for short circular, elliptical and octagonal CFST columns is validated by comparing the predicted results with experimental results.
 
Key Words
    confined concrete model; numerical analysis; concrete-filled steel tubular columns
 
Address
(1) Vipulkumar I. Patel:
School of Engineering and Mathematical Sciences, College of Science, Health and Engineering, La Trobe University, P.O. Box 199, Bendigo, VIC 3552, Australia;
(2) Brian Uy:
School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
(3) Prajwal K.A.:
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India;
(4) Vipulkumar I. Patel, Brian Uy, Prajwal K.A., Farhad Aslani:
Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia;
(5) Farhad Aslani:
School of Civil, Environmental and Mining Engineering, The University of Western Australia, Crawley, WA 6009, Australia.
 

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