Title:
Creep Effects in Plain and Fiber-Reinforced Polymer-Strengthened Reinforced Concrete Beams
Author(s):
M. M. Reda Taha, M. J. Masia, K.-K. Choi, P. L. Shrive, and N. G. Shrive
Publication:
Structural Journal
Volume:
107
Issue:
6
Appears on pages(s):
627-635
Keywords:
creep; deflection; epoxy adhesive; fiber-reinforced polymer (FRP); reinforced concrete
DOI:
10.14359/51664010
Date:
11/1/2010
Abstract:
The long-term deflection behavior of two reinforced concrete (RC) beams with similar dimensions and material properties was monitored. One beam was externally strengthened with fiberreinforced polymer (FRP) strips, whereas the other was used as a control specimen. Both beams have been subjected to sustained loading for over 6-1/2 years. The objective of the experiments was to assess the significance of creep in the epoxy adhesive and whether such creep might allow the FRP strips to unload over time. Slip movements at the ends of the FRP strips were also monitored. The experimental deflections have been compared to deflection predictions using ACI 209R-92 and CEB-FIP MC 90. The creep deformations of the FRP-strengthened beam are not as predicted from the control beam. Two analytical approaches are used: a step-by-step in-time analysis and finite element (FE) modeling. Both techniques demonstrate that creep of the adhesive layer can account for the differences observed between the predicted and actual behaviors of the beams.