Static Performence Of Anchorage For Prestressed CFRP Plate In Strengthening Of Steel Beam

Carbon fiber reinforcement polymer (CFPR) plate has advantages of high strength, corrosion resistance and low density. Bonding CFRP plates to structures is widely used in the field of structure reinforcement. However, there are some problems for this method: such as stress lag, requirement of smooth interfaces and influence of high temperature and corrosion of the adhesive layer. Unbonded prestressed CFRP plate can solve the problems above and has a good prospect while the anchorage is critical for the use of prestressed CFRP plate. A new mechanical anchorage system used for prestressing CFRP plate is introduced in this thesis. The static behaviors of the presented anchorage system were studied theoretically and experimentally:1) Several existing anchorages were reviewed and their analytical theories, techniques and results were also discussed.2) A 3D finite element model was established to investigate compression stress distribution on CFRP plates and the parametric analysis was also conducted. The results show that:incising and thickening clamping piece make the compression stress distribution more even; increasing the pre-tightening force from the high strength bolts changes the distribution slightly but increases the maximum compression stress significantly.3) The experiments were carried out in which CFRP plates were anchored and loaded to failure. The failure modes of CFRP plates and the influencing factors were analyzed numerically and experimentally. It was found that: low longitudinal shear strength of CFRP plates and uneven distribution of compression stress on the CFPR plates are two critical causes for the rupture of the plates; the capacity of the anchorage can be improved with the increase of pre-tightening force from the high strength bolts and amelioration of the clamping piece interface, and furthermore, the thickness of the CFRP plate also has an slight effect on the capacity of the anchorage.4) The anchorage system was used for strengthening steel beams under cycling load. The results show that the anchorage performs well and reliably.