The Ageing Effect of CFRP Plate Steel Members

Fiber Reinforced Polymer (FRP) has been used for many years in structures retrofitting and rehabilitation especially in concrete member. Numerous efforts have been employed to translate FRP-to-concrete application into steel retrofitting. Debonding of CFRP form steel surface have been a crucial issue in the field of strengthening and retrofitting of offshore steel structure. In this paper, the effect of CFRP-plated steel member under accelerated saltwater condition is presented by submerging the CFRP plated-steel member into accelerated seawater of 60⁰C for 1 month, 2 months, and 3 months. Since debonding is the most crucial aspect in CFRP-to-steel joint, the understanding on bond-slip characteristic is the focus of this paper. Additionally, two innovative theories, which are pull-test and numerical method, are demonstrated on the characteristics of bond-slip degradation. In addition, the material strength and stiffness of SikaCarbodur CFRP and Sika30 Adhesive is also measured. Based on the joint pull test, the weakest link of the bonded interfaces is the adhesive, provided that adhesion failure at steel/adhesive and CFRP/adhesive interface can be avoided by a good and appropriate surface preparation of steel and FRP. The failure mode and load-displacement curve will be analyzed in order to investigate the bond-slip relationship of CFRP-to-steel.