Cyclic behaviour of UHPC columns with hybrid CFRP/Steel reinforcement bars. (1st July 2021)

• Record Type: Journal Article
• Authors: Hu, Rui; Fang, Zhi; Benmokrane, Brahim; Fang, Wenchang
• Is Part Of: Engineering structures. Volume 238(2021)
• Publication Date: 2021-07-01
• Subjects: Ultra-high-performance concrete (UHPC) -- Carbon fibre-reinforced polymer (CFRP) -- Hybrid reinforcement -- UHPC columns -- Cyclic behaviour; Structural engineering -- Periodicals; Structural analysis (Engineering) -- Periodicals; Construction, Technique de la -- Périodiques; Génie parasismique -- Périodiques; Pression du vent -- Périodiques; Earthquake engineering; Structural engineering; Wind-pressure; Periodicals; 624.105
• DOI: 10.1016/j.engstruct.2021.112245
• Languages: English
• ISSNs: 0141-0296

Abstract

Highlights: A new kind of structural system, UHPC columns with hybrid reinforcement, is proposed; Quasi-static tests of four UHPC columns with hybrid reinforcement are conducted; Influences of CFRP bars and axial-load ratio on the UHPC columns are analyzed; The design axial-load ratio limit of the hybrid UHPC columns is proposed; A proper replacement ratio of CFRP bars was suggested for the hybrid UHPC columns. Abstract: A new type of reinforced concrete column with ultra-high-performance concrete (UHPC) and hybrid carbon fibre-reinforced polymer (CFRP) and steel bars is proposed in this paper. The CFRP bars with an excellent linear elastic property are used in the columns to enable the expected self-centring capacity. Steel bars with good plastic properties and high ductility UHPC were used to maintain the high energy-dissipation capacity of the columns. Four UHPC columns were tested under reversed cyclic lateral loading; the behaviour of the UHPC columns with hybrid CFRP/steel reinforcement bars was analysed numerically using OpenSees, and the influences of the CFRP bars and axial-load ratio on the seismic behaviour of the columns were analysed. The results indicate that the strain in the longitudinal bars at the ultimate state is a crucial criterion for determining the effectiveness of the CFRP bars. The UHPC columns with the hybrid CFRP/steel reinforcement exhibit both excellent self-centring capacity and good energy dissipation when the design axial-load ratio is less than 0.7. The replacement ratio of the CFRP bars is suggested to be 1/3–2/3 so that the self-centring and energy-dissipation capacity of the UHPC columns with hybrid CFRP/steel reinforcement bars can be balanced.