Abstract Fiber reinforced polymer (FRP) is increasingly used to strengthen damaged or structurally unsafe concrete bridges. The FRP wrapping on eight concrete bridges was evaluated with ASTM pull-off testing to assess the condition of the bonding. A majority of samples failed in the concrete substrate. However, large variations in failure modes and pull-off strengths were observed, possibly due to environmental degradation or improper application. A majority of samples failed in the ASTM Mode G in concrete. Average bond strength from columns samples was 20 % lower than that from girders, due to the difficulty of pull-off testing on round column surfaces.