Axial performance of short concrete filled steel tubes with high- and ultra-high- strength materials

• Published in: Engineering structures Vol. 136; pp. 494 - 510
• Main Authors: Xiong, Ming-Xiang, Xiong, De-Xin, Liew, J.Y. Richard
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2017; Elsevier BV
• Subjects: Ambient temperature; Analytical methods; Applications programs; Axial stress; Building codes; Buildings; Composite materials; Compression; Compressive strength; Concrete; Concrete filled steel tubes; Cross-sections; Cylinders; Design; Eurocode 4; High rise buildings; High strength; High strength concretes; High strength steel; High tensile steel; Modifications; Plastics; Reinforced concrete; Short columns; Steel; Steel columns; Steel tubes; Studies; Temperature effects; Tensile strength; Ultra-high strength concrete; Ultrahigh temperature; Yield strength; Modifications; Eurocode 4; Concrete filled steel tubes; Ultra-high strength concrete; High tensile steel; Short columns
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2017.01.037

•Axial performance of ultra-high strength CFST columns is presented.•Measures to improve ductility are provided.•Confinement effect should be ignored for calculating axial resistance.•Modified Eurocode 4 method is applicable to ultra-high strength CFST columns. The use of high strength concrete and steel have significant advantages for composite members subject to significant compression as in the cases of high-rise buildings. Current design codes place limits on the strengths of steel and concrete due to limited test data and experience on the behaviour of composite members with the high strength materials. To extend their applications, a comprehensive experimental program has been carried out to investigate the behaviour of concrete filled steel tubes (CFSTs) with high- and ultra-high- strength materials at ambient temperature. This article presented some new findings on the axial performance of 56 short CFSTs. High tensile steel with yield strength up to 780MPa and ultra-high strength concrete with compressive cylinder strength up to 190MPa were used to prepare the CFST test specimens. The key issue is to clarify if the plastic cross-sectional resistance could be used at ultimate limit state as for CFSTs with the normal strength materials. To address this, experimental and analytical methods were adopted where the test results were compared with the predictions by various design codes world widely, and design recommendations were therefore proposed so that the prediction methods could be safely extended to the short CFSTs with the high- and ultra-high- strength materials.