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(2020) 20:126

ORIGINAL ARTICLE

Seismic behaviour of cross‑shaped steel fibre reinforced concrete columns Linzhu Sun1 · Zhengzhen Wei1 · Wei Li1   · Jinhuai Xiang1 Received: 5 May 2020 / Revised: 14 August 2020 / Accepted: 10 September 2020 © Wroclaw University of Science and Technology 2020

Abstract This paper proposes a novel cross-shaped column in which steel fibre reinforced concrete (SFRC) is integrated with a highstrength stirrup to enhance its seismic behaviour. An experimental investigation was conducted on eight cross-shaped column specimens subjected to cyclic lateral loading. All of the specimens were evaluated in terms of their cracking patterns, failure modes, hysteresis behaviour, deformation and ductility, strength and stiffness degradation, and energy dissipation performance. The effects of the stirrup strength, stirrup spacing, steel fibre content, and axial load ratio were investigated. The experimental results demonstrated that all of the specimens exhibited flexural failure. The cracked concrete of the specimens with steel fibres could be prevented from spalling. The hysteresis loops of all of the specimens were relatively full without a readily observable pinching phenomenon and the specimens possessed a satisfactory energy dissipation capacity. Compared with the normal specimens, the specimens with high-strength stirrups, close stirrup spacing, and steel fibre exhibited a higher energy dissipation capacity, lateral bearing capacity, displacement ductility, and initial stiffness. However, the ductility rapidly decreased as the axial load ratio increased. Additionally, neither the incorporation of steel fibre nor the reduction of the stirrup spacing or the axial load ratio substantially mitigated the stiffness degradation. Based on the test results, calculation models were proposed for calculating the seismic bending moment capacities of the specimens. The calculated values were in accordance with the test results. Keywords  Cross-shaped column · Seismic behaviour · Steel fibre concrete · High-strength stirrup · Bending moment capacity

1 Introduction Compared with a rectangular-section or square-section column structure, a special-shaped column structure realizes the combination of architectural beauty and flexibility of use, reduces structural weight, effectively improves a building utilization rate, and increases the use area of a house. As a new structural type, it is promoted due to its unique social, economic, and environmental advantages. However, long-term experimental research and theoretical analysis have identified its weaknesses. A special-shaped column replaces a normal rectangular or circular column with a special-shaped cross-section, such as an L shape, a T shape, a Z shape, or a cross shape. However, compared with * Wei Li [email protected] 1



College of Civil Engineering and Architecture, Wenzhou University, Wenzhou 325035, People’s Republic of China

a rectangular column, it exhibits poor mechanical performance, energy dissipation performance, and ductility. The