CYCLIC TESTING OF GLUED-IN FRP RODS IN TIMBER

Glued-in GFRP and CFRP rods are tested under both tension and compression in a cyclic loading regime. The effect of different construction cases in the axial stiffness of the connections is studied. The experimental results showed that GFRP rods have higher axial load capacity and lower axial stiffness than CFRP rods. The increase in the axial load capacity of the GFRP rods is non-linear with increasing bonded length and current design recommendations for glued-in steel rods do not agree well with experimental results. Gaps due to construction tolerances or long-term shrinkage effects can affect significantly the compressive stiffness of the glued-in rod connections. The tension stiffening effect results in axial tensile stiffness variations along the bonded length and the axial compressive stiffness complies with the full-composite action assumption. An analytical study is presented that predicts debonding failure near the loaded end. The analytical slip values under both tension and compression agree fairly well with the experimental findings.