Direct Strength Method–Based Approach for Strength Prediction of Pultruded GFRP Angle Columns
Publication: Journal of Composites for Construction
Volume 27, Issue 3
Abstract
This paper introduces a new design procedure for the strength prediction of pultruded glass fiber–reinforced polymer (pGFRP) angles subjected to compression through a parametric analysis. Experimental results were used for the calibration of a finite-element numerical model according to linear and nonlinear analyses. Sensitivity to the initial geometric imperfections, material damage, and leg-junction rotational stiffness was then investigated for an evaluation of the influence of material and geometric nonlinearities on the column behavior. A parametric study including 100 pGFRP angles within slenderness ranges not covered by previous tests was developed for increasing the available data, and the results were evaluated by two normative and four nonnormative design procedures. Finally, a new design procedure based on the direct strength method (DSM) is proposed. It adopts modified global and local strength curves of the original American Specification for the Design of Cold-Formed Steel Structural Members (AISI) from the adjustment of the original expressions based on a large database, including experimental data collected from the literature and numerical data obtained from the parametric study. The proposed DSM approach led to accurate ultimate strength estimates for columns covering a wide slenderness range.
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Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001, and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)—Grant Number 141880/2020-1.
Notation
The following symbols were used in this paper:
- Ag
- gross area of cross section;
- b
- width of angle leg;
- D
- transducer displacement;
- E
- elastic modulus;
- EL
- longitudinal elastic modulus;
- E2
- transverse elastic modulus;
- E2,l
- angle’s leg transverse elastic modulus;
- E2,j
- angle’s junction transverse elastic modulus;
- Ef
- modulus of fiber;
- Em
- modulus of matrix;
- longitudinal compression material strength;
- fy
- yield stress;
- Gi,c
- fracture energies of each i-failure mode;
- Gij
- shear modulus in plane ij;
- GLT
- in-plane shear modulus;
- Ki
- buckling coefficient about the i-axis;
- KiLi
- effective length about the i-axis;
- L
- column length;
- ME
- model error;
- P
- load;
- longitudinal compression material load;
- Pmodel
- ultimate load from design model;
- Pnum
- ultimate load from numerical analysis;
- Pcr
- critical buckling load;
- Pcr,g
- global buckling load;
- Pcr,l
- local buckling load;
- PcrFMT
- flexural–torsional buckling load;
- Pcrt
- torsional buckling load;
- Pcrz
- flexural buckling load about the minor axis;
- Pu
- ultimate load;
- r0
- polar radius of gyration;
- rz
- radius of gyration about the z-axis;
- Sti
- tensile strength in the i-direction;
- Sci
- compression strength in the i-direction;
- Sij
- shear strength in the ij plane;
- t
- angle leg thickness;
- tCSM
- thickness of CSM layer;
- tf
- thickness of roving layer;
- VCSM
- CSM volume fraction;
- VRov
- roving volume fraction;
- y0
- distance from the centroid to the shear center of the cross section;
- δ
- displacement;
- δ0
- initial geometric imperfection of a column;
- λFm
- flexural buckling relative slenderness;
- λFMT
- flexural–torsional relative slenderness;
- υf
- Poisson’s ratio of fiber;
- υLTυ12
- major Poisson’s ratio;
- υm
- Poisson’s ratio of matrix; and
- υTL
- minor Poisson’s ratio.
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Published In
Journal of Composites for Construction
Volume 27 • Issue 3 • June 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Jul 20, 2022
Accepted: Dec 8, 2022
Published online: Feb 17, 2023
Published in print: Jun 1, 2023
Discussion open until: Jul 17, 2023
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