Techno Press

Steel and Composite Structures   Volume 22, Number 6, December30 2016, pages 1487-1505
Behavior of CFST columns with inner CFRP tubeunder biaxial eccentric loading
Guochang Li, Zhijain Yang, Yan Lang and Chen Fang

Abstract     [Full Text]
    This paper presents the results of an experimental study on the behavior of a new type of composite FRP-concrete-steel member subjected to bi-axial eccentric loading. This new type of composite member is in the form of concrete-filled square steel tube slender columns with inner CFRP (carbon fiber-reinforced polymer) circular tube, composed of an inner CFRP tube and an outer steel tube with concrete filled in the two tubes. Tests on twentysix specimens of high strength concrete-filled square steel tube columns with inner CFRP circular tube columns (HCFST-CFRP) were carried out. The parameters changed in the experiments include the slenderness ratio, eccentric ratio, concrete strength, steel ratio and CFRP ratio. The experimental results showed that the failure mode of HCFSTCFRP was similar to that of HCFST, and the specimens failed by local buckling because of the increase of lateral deflection. The steel tube and the CFRP worked together well before failure under bi-axial eccentric loading. Ductility of HCFST-CFRP was better than that of HCFST. The ultimate bearing capacity of test specimen was calculated with simplified formula, which agreed well with test results, and the simplified formula can be used to calculate the bearing capacity of HCFSTF within the parameters of this test.
Key Words
    CFRP tube; high strength concrete-filled square steel tube; bi-axial eccentric; slenderness ratio; slender column
(1) Guochang Li, Zhijain Yang:
School of Civil Engineering, Shenyang Jianzhu University, Shenyang, 110168, China;
(2) Yan Lang:
cDepartment of Building Engineering, Suqian College, Jiangsu Province, 223800, China;
(3) Chen Fang:
Department of Civil Engineering, University of Texas at El Paso, El Paso, TX 79968, USA.

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