Shear Design of Reinforced Concrete Beams Strengthened in Shear with Anchored Carbon Fiber-Reinforced Polymer (CFRP) Strips

Design guidelines and recommendations for reinforced concrete (RC) beams strengthened in shear with anchored carbon fiber-reinforced polymer (CFRP) strips are presented. The proposed design guidelines were developed by investigating shear contributions and limits of the CFRP, concrete, and steel based on a database of 42 large-scale RC beam tests. The proposed concrete contribution equation was derived to account for the influence of the shear span-depth ratio and transverse reinforcement as indicated by the database. The evaluation of the steel and CFRP contribution is based on the well-known variable angle truss model. A model was developed to evaluate the effective strain of the anchored CFRP material based on the axial rigidity of the CFRP strips. An effective strain upper limit was imposed to prevent the premature loss of aggregate interlock The shear capacity using the proposed design guidelines was compared with test results and current ACI design guidelines.