Investigation on the flexural–tensile behaviour of CFRP tendon composite anchorage system

The cable at the anchorage end is in a bending–tension condition in service due to the variable loads. A new composite anchorage system was proposed to study the flexural–tensile behaviour of the anchorage system with CFRP tendon. Four groups of single-tendon composite anchorage and three groups of five-tendon composite anchorage with bend restrictor were tested. Besides, one group of five-tendon composite anchorage without bend restrictor was tested as a control group. The effects of the bending angle, inner cone angle of the steel barrel and pre-tension force on the flexural–tensile behaviour of the anchorage system were investigated. The internal force state of the tendon inducing different failure modes was analysed. A finite element method was used to analyse the failure mechanism of the anchorage system under the bending–tension condition. Moreover, the flexural–tensile behaviours of the anchorage systems with different elastic moduli of the bonding medium were compared. Results showed that the efficiency coefficients of the composite anchorage with multi-tendon exceeded 0.9 when the end bending angle was less than 4.2°. The setting of the bending restrictor improves the flexural–tensile bearing capacity of the anchorage system and increases the maximum allowable bending angle. A larger bending angle will lead to a faster increase in the transverse shear stress at the loading end. Furthermore, increasing the pre-tension force can prompt the cooperation ability of the tendons and reduce the ultimate slips, thus improving the ultimate load-bearing capacity of the anchorage. The increase in the elastic modulus remarkably reduces the slip of the tendon, but increases the shear stress at the loading end under the bending–tension condition.