ABSTRACT
Recently the application of resin-impregnated high-strength fiber rods (FRP) as concrete reinforcement or prestressing tendons are actively studied. The aims of these investigations are to improve durability, increase strength, or to improve the electro-magnetic characteristics of concrete structures. But usually FRP rods involve some problems such as low modulus and low bond strength to concrete. The authors have proposed braiding the fibers to improve the bond properties of FRP, and have found that partially prestressing was effective for the beams using FRP which had low sectional rigidities.
The authors conducted long term loading tests on partially prestressed concrete beams reinforced and pre-stressed with braided aramid fiber rods to investigate the long term reliability of these fiber rods.
The test results demonstrated that partially prestressing was effective in improving long term serviceability such as deflections and cracking. Computational method to estimate long term deflection and crack width for the beams using FRP are also discussed.
