Buckling behaviour of high strength concrete encased steel composite columns

• Published in: Journal of constructional steel research Vol. 154; pp. 27 - 42
• Main Authors: Lai, Binglin, Richard Liew, J.Y., Wang, Tongyun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2019
• Subjects: Buckling resistance; Concrete encased composite columns; Effective flexural stiffness; High strength concrete; Member imperfections; Effective flexural stiffness; Concrete encased composite columns; Buckling resistance; Member imperfections; High strength concrete
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2018.11.023

This paper provides an insight into the buckling behavior of high strength concrete encased steel (CES) columns through a comprehensive investigation including experimental, numerical and analytical analyses. Three long CES column specimens made of high strength concrete C100 and S355 H-section were tested under axial compression. The maximum test loads obtained from these tests were compared with the buckling resistance predicted by EN 1994-1-1, AISC 360-10 and ACI 318-08. Nonlinear finite element analyses were performed to predict the buckling resistance and trace the load displacement behaviour of these columns. In the finite element model, the column initial imperfections were carefully chosen to predict the maximum resistance and the load-displacement response, and compared with the equivalent imperfection values stipulated in the modern design codes. In order to examine the validity and limitation of the current design approaches in predicting the buckling resistance of CES columns made of high strength concrete, a statistical study was undertaken based on the established database covering a wider range of material strength and geometric configurations. In the statistical study, the buckling resistance and effective flexural stiffness obtained from the tests were compared with the codes' predictions from EN 1994-1-1, AISC 360-10 and ACI 318-08. Finally, the reliability of the current design methods is assessed by correlating their accuracy with respect to the variation of material strength, column slenderness ratio, load eccentricity and steel contribution ratio. •The compression behaviour and maximum resistance of high strength concrete encased steel composite columns were investigated.•New test database including 3 large scale tests carried out on high strength composite columns subject to axial compression was reported.•The test failure loads were compared with codes' predictions and numerical results from nonlinear finite element analyses.•The effective flexural stiffness of high strength composite members predicted by design codes was comparatively studied.