Abstract
Fiber-reinforced polymer (FRP) wrapping has become an attractive strengthening technique for concrete columns. However, the ingress of corrosion into the concrete through the gap of CFRP fiber greatly reduces the durability of concrete and the bearing capacity of specimens. Concrete canvas, a kind of corrosion-resistant and refractory material, is a promising method to enhance durability and carrying capacity. In this study, the concrete canvas (CC) and carbon fiber-reinforced polymer (CFRP) were used to jointly reinforce columns with square cross section, octagonal cross section, circular cross section, and elliptical cross section. The influence of section shape on the strengthening effect of the axial compression column was investigated by the axial compression test. The results showed that the section shape had a significant influence on the reinforcement effect of the axial compression column. The carrying load capacity and ductility coefficient of different columns follow this order: square column < oval-shaped columns < octagonal columns < circle columns. The increased amplitude of bearing capacity for the different columns with the increase of CC layers follows this order: square columns < oval-shaped columns < circle column < octagonal columns. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 129%, 155%, 150%, and 139% for the square, octagonal, circular, and elliptical columns, respectively. The octagonal column has the largest increase range. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 348%, 318%, 310%, and 296% for the square, octagonal, elliptical, and circular columns, respectively. The square column has the largest increase range. The stress concentration phenomenon of all section shapes was weakened after the CC was used. The application of the CC on CFRP-reinforced columns improves column ductility significantly, with some degree of increase in bearing capacity.
Highlights
carbon fiber-reinforced polymer (CFRP) has been used frequently in the reinforcement of various components, mainly because they have better mechanical properties and corrosion resistance than traditional building materials [1,2,3,4,5,6,7,8]
Based on the above analysis, this study provides new reinforcement insights (CC and CFRP joint reinforcement) to improve the mechanical properties and durability of reinforced columns. e study in this article comprehensively investigates the improvement of the mechanical behavior of concrete canvas (CC) and CFRP reinforcement for different cross-sectional shapes
CFRP rupture of square and octagonal columns occurs at the corner first, which is in accordance with the experimental observations from some other researchers [27, 28, 32, 39]
Summary
Received 2 February 2021; Revised 11 April 2021; Accepted 26 April 2021; Published 12 May 2021. The concrete canvas (CC) and carbon fiber-reinforced polymer (CFRP) were used to jointly reinforce columns with square cross section, octagonal cross section, circular cross section, and elliptical cross section. E carrying load capacity and ductility coefficient of different columns follow this order: square column < oval-shaped columns < octagonal columns < circle columns. E increased amplitude of bearing capacity for the different columns with the increase of CC layers follows this order: square columns < oval-shaped columns < circle column < octagonal columns. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 348%, 318%, 310%, and 296% for the square, octagonal, elliptical, and circular columns, respectively. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 348%, 318%, 310%, and 296% for the square, octagonal, elliptical, and circular columns, respectively. e square column has the largest increase range. e stress concentration phenomenon of all section shapes was weakened after the CC was used. e application of the CC on CFRP-reinforced columns improves column ductility significantly, with some degree of increase in bearing capacity
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