Moment curvature relationship of concrete member reinforced with CFRP rods and steel bars

Placing proper amount of CFRP rods in steel reinforced concrete member can realize self-monitoring by taking advantage of their smart characteristics as well as utilizing their rather high tensile strength. In view of this kind of reinforcement style and existent experiment data of CFRP rods, a three-lined moment-curvature relationship is presented herein, in which some relative exact formulae are given accordingly. To ensure that steel bars can yield before the concrete member reach its flexural capacity and CFRP rods do not rupture until concrete compressive layer crushes, an appropriate range of reinforcement ratio of steel bars and CFRP rods is suggested. By an example, the effects of global reinforcement ratio and each reinforcement ratio on cross section characteristics of bearing capacity are demonstrated.