TY - JOUR
T1 - Load-strain model for concrete-filled double-skin circular FRP tubes under axial compression
AU - Li, Y. L.
AU - Zhao, Xiao Lin
AU - Singh Raman, R. K.
N1 - Funding Information:
The financial support provided by the Australian Research Council (ARC Discovery Grant, DP160100739 ) is greatly appreciated by the authors. The authors are grateful for the helpful advice provided by Prof. Jin-Guang Teng during the present study.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2019/2/15
Y1 - 2019/2/15
N2 - Concrete-filled double-skin FRP tubes (CFDST) are increasingly attracting researchers’ interests due to the advantages of their reduced self-weight and higher bending stiffness than fully filled tubes. However, the structural behaviour of CFDST, especially the non-uniform confinement in annular concrete, has not ever been well addressed. This paper presents an analytic study on axial compressed circular stub CFDST with FRP wrap/tube as outer tube and steel/FRP as inner tube. Based on existing studies on actively confined concrete, a constitutive model for non-uniformly FRP-confined concrete is developed in this paper. The dilation model for concrete fully filled FRP tubes is modified to account for the effects of void ratio so that the hoop-axial strain curve of CFDST could be reasonably predicted. Behaviours of steel and FRP tubes in CFDST are investigated and proper stress-strain models are proposed to estimate the loads shared by tubes. The stress state in annular concrete is theoretically studied by dividing the cross-section into multiple circular layers. Finally, an analysis-oriented load-strain model, which accounts for the non-uniform confinement, effects of void ratio, buckling of FRP tube, and strain hardening of stainless steel, is proposed for CFDST. As validated by the experimental data from a wide range of literature, the proposed model is reasonable and of high accuracy.
AB - Concrete-filled double-skin FRP tubes (CFDST) are increasingly attracting researchers’ interests due to the advantages of their reduced self-weight and higher bending stiffness than fully filled tubes. However, the structural behaviour of CFDST, especially the non-uniform confinement in annular concrete, has not ever been well addressed. This paper presents an analytic study on axial compressed circular stub CFDST with FRP wrap/tube as outer tube and steel/FRP as inner tube. Based on existing studies on actively confined concrete, a constitutive model for non-uniformly FRP-confined concrete is developed in this paper. The dilation model for concrete fully filled FRP tubes is modified to account for the effects of void ratio so that the hoop-axial strain curve of CFDST could be reasonably predicted. Behaviours of steel and FRP tubes in CFDST are investigated and proper stress-strain models are proposed to estimate the loads shared by tubes. The stress state in annular concrete is theoretically studied by dividing the cross-section into multiple circular layers. Finally, an analysis-oriented load-strain model, which accounts for the non-uniform confinement, effects of void ratio, buckling of FRP tube, and strain hardening of stainless steel, is proposed for CFDST. As validated by the experimental data from a wide range of literature, the proposed model is reasonable and of high accuracy.
KW - Axial compression
KW - Concrete-filled double-skin FRP tube
KW - Dilation property
KW - Load-strain model
KW - Non-uniform confinement
UR - http://www.scopus.com/inward/record.url?scp=85058777806&partnerID=8YFLogxK
U2 - 10.1016/j.engstruct.2018.12.029
DO - 10.1016/j.engstruct.2018.12.029
M3 - Journal article
AN - SCOPUS:85058777806
SN - 0141-0296
VL - 181
SP - 629
EP - 642
JO - Engineering Structures
JF - Engineering Structures
ER -