Prestressing Effects of Jacking-Cambered Wood Beams Reinforced with FRP Strips

When a wood beam is cambered by jacking and then bonded with a laminate of fiber reinforced polymer (FRP), the established prestress is low due to the limitation of interfacial bonding capacity. In this paper, self-locking anchorage is added to the strip end of FRP to prevent the debonding failure, which results in cambered beams with end anchored or hybrid anchored FRP. The relations of the FRP tensile stress, effective compressive prestress at the bottom of the beam, and retained camber with the jacking force and the related parameters of the beam and FRP strip are obtained by detailed derivation. The results show that when the FRP tensile stress is critical at the limit state, the lower stress in a cambered beam with end anchored FRP is advantageous to bear greater external load without fracture of FRP. If the ultimate behavior of a cambered beam reinforced with FRP is dominated by conditions of the original beam, hybrid anchorage can achieve larger camber and compressive prestress at the bottom of the beam, which is conducive to counteracting the deflection in service and tensile stress produced by the load.