UNIFIED DEFINITION OF SAFETY FACTORS FOR TRADITIONAL RC MEMBERS AND MEMBERS INCORPORATING FRP

Due to the difference material mechanical properties of FRP with those of concrete and steel, the behaviours of members incorporated FRP are consequential different to the traditional RC members and steel members. The conventional safety theory and design method developed based on the behaviours of the traditional RC members and steel members are not suitable for the members incorporating FRP. The mechanical behaviours of the members incorporating FRP are compared with that of the traditional RC members and steel members, and the safety method is anatomized. It is pointed out that the overall safety margin of a member can be represented by strength margin, deformation margin and deformation energy margin, but the safety factor is usually represented by strength margin for the traditional RC members and steel members, which is not suitable for the members incorporated FRP. A concept of the equivalent strength safety factor Keq composing the overall safety margin is presented, which give unified definition of safety factors for members with different kinds of mechanical behaviours. The suggested unified definition of safety factors is applied to the design method for external bonded FRP strengthening concrete beams, FRP-concrete composite beams, concrete beams reinforced FRP bars and FRP decks, respectively. Safety design suggestions for the members incorporating FRP are pointed out.