Compression-bending behavior of irregular pentagonal CFT columns with different cavity structures: Experimental study

• Published in: Journal of Building Engineering 2023-05, Vol.67, p.105972, Article 105972
• Main Authors: Wu, Hai-Peng, Qiao, Guang-Ping, Han, Xiao-Dong, Ma, Hong-xin, Cao, Wan-Lin, Xia, Dong-Rui
• Format: Article
• Language: English
• Subjects: Cavity structure; Fiber model method (FMM); Hysteretic behavior; Low cyclic test; Pentagonal concrete filled steel tube (PCFT)
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2023.105972

This paper reported the test results of six irregular pentagonal concrete filled steel tube (CFT) columns with different cavity structures. The columns were tested under a constant axial compression and lateral low cyclic load. The test parameters are the lateral loading direction, cross-sectional cavity quantities, and with or without embedded reinforcements. The influence of these parameters on failure mode, strength, elastic-plastic deformability, energy dissipation ability was investigated. It was found that, irregular pentagonal CFT columns exhibit favorable ductility and energy dissipation ability. The multi-cavity structure significantly increases strength, while the reinforcements effectively improve ductility. Also, the bottom cross section strain distribution nephogram was mathematic fitted according to the measured gauge values. And it was founded that the bottom cross-sectional deformation obeys the plane cross section assumption before and at peak load point. And then, a calculation model using fiber model method was established considering difference among the cavity structures. The lateral load versus displacement curves, and axial load versus ultimate moment correlation curves are all predicted. Analysis shows that the constitutive relationship of confined concrete suggested by the author is better than available Han's in the prediction accuracy. •An unusual experimental study on the seismic behavior of a pentagonal CFT columns with multi-cavity structure.•The plane cross-section assumption is verified by the method of strain gauge values mathematical surface fitting.•A fiber model method was used to predict the F-U curves and N-M correlation curves.