Bond-Slip Model for FRP Laminates Externally Bonded to Concrete at Elevated Temperature: Fid-Bau Portal

Bond-Slip Model for FRP Laminates Externally Bonded to Concrete at Elevated Temperature

Dai, Jian-Guo / Gao, W. Y. / Teng, J. G.

This paper presents a nonlinear local bond-slip model for fiber reinforced polymer (FRP) laminates externally bonded to concrete at elevated temperature for future use in the theoretical modeling of fire resistance of FRP-strengthened concrete structures. The model is an extension of an existing two-parameter bond-slip model for FRP-to-concrete interfaces at ambient temperature. The two key parameters employed in the proposed bond-slip model, the interfacial fracture energy, $G_{f}$ , and the interfacial brittleness index, $B$ , were determined using existing shear test data of FRP-to-concrete bonded joints at elevated temperature. In the interpretation of test data, the influences of temperature-induced thermal stress and temperature-induced bond degradation are properly accounted for. As may be expected, the interfacial fracture energy, $G_{f}$ , is found to be almost constant initially and then starts to decrease when the temperature approaches the glass transition temperature of the bonding adhesive; the interfacial brittleness index, $B$ , exhibits a similar trend. The proposed temperature-dependent bond-slip model is shown to closely represent the test data upon which it is based, despite the large scatter of the test data.