Abstract: FRP anchors are proposed to be advanced in impeding debonding failure between strengthened concrete surface and FRP.Influence of varied depth of FRP anchors on pullout properties of FRP strengthening concrete structures is comparatively investigated by pullout experiment that is in light of ACI experimental guidance.The parameters are set by control specimen and experimental specimens which are armed with 3 groups of anchors whose depth are 15 mm,30 mm and 45 mm,respectively.To analyze the results,the failure modes of debonding inside of shallow concrete,concrete cone,concrete cone combined with partial anchors pullout,debonding inside of shallow concrete combined with anchor rupture and debonding in both shallow concrete and FRP are totally derived.Moreover,the bond strength of FRP and concrete surface are increased with depth of FRP anchors.As well,the depth of the anchors are supposed to set more than 30 mm when applied to concrete with cylindrical compressive strength of 30 MPa.To sum,conclusions for this experiment is available to aid design of FRP anchors.

Key words: FRP anchor;anchor depth;FRP strengthening;pullout experiment;debonding failure