Despite
the significant importance, residual seismic behavior of reinforced concrete
(RC) columns
retrofitted
with fiber-reinforced plastic (FRP) has received
little attention. In this paper, the residual performance of FRP
retrofitted columns damaged after simulated seismic loading is studied. Eight model columns
with a shear aspect ratio of 5.0 were tested first under cyclic lateral force
and a constant load equal to 20% of the column gross axial load capacity. The
main parameters considered were the type of FRP jacket and peak drift ratio
where the lateral loading was interrupted. Five of the model columns were
subjected to long-term axial loading after subjected to limited damage by
lateral cyclic loading. The deformation of retrofitted columns under long-term
axial loading related to the previous damage intensity and the modulus of FRP.
The post damage long-term axial strain corresponding to time increment can be
simply estimated using the ACI 209 creep model. The effective creep Poisson’s
ratios of the retrofitted columns were much smaller than the as-built column
but identical for GFRP and CFRP retrofitted columns. Under the testing
condition of this study, the long-term axial deformation of retrofitted column
tends to be stable, despite subjected simulated earthquake damage.