Temperature effect on buckling behavior of prestressed CFRP-reinforced steel columns

Prestressed carbon fiber reinforced polymer (CFRP)-reinforced steel columns behave differently under extreme temperature conditions because CFRP prestress changes with temperatures varying and is a key factor influencing the buckling behavior of such columns. This paper deeply studies the temperature effect on the buckling behavior of the composite columns. First, varying material properties from −80 to 80 °C are studied, and the temperature effect mechanism on the buckling behavior of such column is investigated. Moreover, analyses of two temperature situations are conducted using finite element modeling. When the column is loaded at a certain temperature, the buckling capacity maintains almost constant with temperature varying from 20 to 80 °C, while it increases 3%–7% when the temperature drops from 20 to −80 °C. When the column is preloaded and then the temperature changes, from 20 to 80 °C, the column extends, and the deformation is first symmetric and global and then changes to local and asymmetric when the temperature reaches a turning point; from 20 to −80 °C, the column shrinks, and the deformation is symmetric and global. Additionally, varying temperature may lead to a large change in CFRP stress (as high as 321.9 MPa), which causes significant reduction in the buckling capacity (as much as 18%). These findings provide valuable references for the design of such columns and related thin-walled structures under extreme temperature conditions.