On Rehabilitation of Steel Building Using Bonding Carbon Fiber Reinforced Plastic Plates

Aging of existing steel buildings necessitate the development of simple and efficient rehabilitation technique. We have been developing a strengthening method with bonding Carbon Fiber Reinforced Plastic Plate (CFRP) to enhance the usage life of steel buildings. Coefficient of expansion of CFRP is one-tenth smaller than that of steel. The change of temperature during daytime and night amounts to 40 deg C so that large thermal stress occurs in adhesive layer between CFRP and steel. Cyclic thermal stress causes degradation of the bonding strength. Further, CFRP and steel have electro-conductivity. Although the adhesive between CFRP and steel has non-electro-conductivity, intense rust (galvanic corrosion) may occur when CFRP partially touches steel member. The partial galvanic corrosion may deteriorate the bonding strength between CFRP and steel. In this study, Heat cycle tests on steel plate bonding CFRP are made to evaluate the durability of cyclic thermal stress. Also, galvanic corrosion tests under dry and wet cycle atmosphere using salt water are carried out. We show these basic data for influence of galvanic corrosion and cyclic thermal stress on bonding strength between CFRP and steel plate.