Design Implications of Creep and Long-Term Deflections in FRP-RC Beam-Columns

Abstract

This paper will discuss that most studies have focused on short term behavior of fiber reinforced polymer (FRP)-reinforced concrete (RC) members, but it is important and necessary to study their time-dependent behavior, if FRP is to be used as a viable alternative reinforcement for the infrastructure. The present study provides an analytical tool to assess serviceability issues of FRP-RC beam-columns under sustained loads. The analytical model accounts for creep of FRP-RC beams and beam-columns. The model is based on age-adjusted effective modulus method for concrete and Findlay’s model for FRP reinforcement. The model has been verified against the FRP-RC beam tests by the authors, as well as those from the literature. A detailed parametric study is then carried out to determine the effects of different types of FRP reinforcing bars on the creep of slender FRP-RC columns, and whether the ACI 318 design provisions for creep of slender RC columns is adequately safe for FRP-RC construction.