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Buckling behaviour of pultruded FRP Members

Researcher: Thuy Nguyen Tien
Project duration: 2010-2013
Supervisors: Dr Tak-Ming Chan and Prof. Toby Mottram
Funding body: Vietnamese Government Scholarship and School of Engineering


Pultruded Fibre-reinforced polymers (FRP) have been widely applied in construction in recent years. This is due to the advantageous properties of FRP materials such as high strength-to-weight ratio, electromagnetic transparency, resistance to corrosion, etc.

However, the literature on design guide as well as the standard for structural engineering applications is limited. To date the only standard specification for pultruded FRP in Europe is EN 13706 which mainly discuss the material test methods. An in-depth understanding about the behaviour of pultruded FRP is needed to facilitate the wider use of pultruded FRP profiles in construction.

Besides, the relatively low elastic modulus of pultruded FRP may result in designs being governed by deflection and buckling limitations, rather than by strength limitations (Chambers 1997). Several researchers have studied Lateral-torsional buckling behaviour of doubly symmetric pultruded FRP member (Mottram, 1992; Turvey 1996; Davalos and Qiao, 1997). But for single symmetric sections such as channels and angles, few experimental data are available for pultruded profiles. In addition, few test data are available for pultruded beam-column profiles (Barbero and Turk, 2000; Mottram et al., 2003). In order to promote the efficient use of pultruded FRP profiles for new-build structures, further experimental work is needed to develop more understanding into the buckling response of beams and columns with varying section, span, height, imperfections, supports and load conditions.


This research aims to investigate the buckling response of pultruded FRP member through non-linear numerical (FE) simulations and experimental works. The general structural performance data obtained from tests and FE modelling will then be utilized to derive design rules in accordance to Euro codes.


The global buckling analysis of FRP will be carried out in three approaches. Theoretical analysis will be made on the behaviour of the structural members through fundamental mechanics and analysis methods. Numerical will be created via the use of a finite element software package such as ABAQUS to determine the structural behaviour. This will then need to be verified and calibrated through a series of experimental tests. Tests will be carried out on materials, cross-sections and structural members. The numerical and laboratory test results will then be processed and analysed to obtain a thorough understanding of global buckling behaviour of pultruded FRP member.


Bank, L.C. (2006) Composites for Construction - Structural Design with FRP Materials. John Wiley & Sons press.

Barbero, E.J. and Turk, M. (2000) Experimental investigation of beam-column behavior of pultruded structural shapes. Journal of Reinforced Plastics and Composites, 19(3), 249-265.

Chambers, R.E. (1997) ASCE design standard for pultruded fiber-reinforced-plastic (FRP) structures. Journal of Composites for Construction, 1 (1), 1997, 26-38.

Davalos, J.F. and Qiao, P. (1997) Analytical and experimental study of lateral and dirtorsional buckling of FRP wide-flange beams. Journal of Composites for Construction, 1(4), 150-159.

Mottram, J.T. (1992) Lateral-torsional buckling of a pultruded I-beam. Composites, 23(2), 81-93.

Mottram, J.T., Brown, N.D. and Anderson D. (2003) Buckling characteristics of pultruded glass fibre reinforced plastic columns under moment gradient. Thin-Walled Structures, 41(7), 619-638.

Roberts, T.M. (2002) Influence of shear deformation on buckling of pultruded fiber reinforced plastic profiles. Journal of Composite Construction, ASCE, 6(4), 241-248.

Roberts, T.M. and Masri H.M.K.J.A.H. (2003) Section properties and buckling of pultruded FRP profiles. Journal of Reinforced Plastics and Composites, 22(14), 1305-1317.

Turvey, G. J. (1996) Effects of load position on the lateral buckling response of pultruded GFRP cantilevers: comparisons between theory and experiment. Composite structures, 35(1), 33–47.