The time-
dependent behavior of
FRP-concrete
interface is big common for concrete structures strengthened with
externally bonded fiber reinforced polymer (FRP) sheets or plates. This paper
is devoted in developing a new nonlinear viscoelastic model for studying the
long.term behavior of FRP-concrete
interface. The model has the ability to
describe creep behavior of FRP-concrete adhesive layer and creep fracture
propagation along the FRP-concrete interface. The creep of FRP-concrete
interface is taken into account by using Maxwell’s generalized rheological
model through a step-by-step time increment model. The nonlinear time-
dependent behavior of adhesive layer depends on the time-dependent degradation of the
bond strength and fracture energy. The proposed model has been calibrated by
using the results of the double lab shear creep test specimens to verify its
validity. The results demonstrate the reliability of the proposed models and
their capability to predict the time-dependent propagation of debonding. The
results show also the ability of this model to predict a wide range of the
creep fracture not only under low sustained loading but also under high
sustained loading.