Peak Stress of FRP-Confined Concrete Columns with Circular and Square Sections

Abstract Fiber reinforced polymer (FRP) has been extensively used to strengthen concrete columns. It is necessary to establish peak stress model with high prediction accuracy for FRP-confined concrete columns. A theoretical peak stress model of actively-confined concrete is proposed based on Jefferson’s failure criterion. And a peak stress model for columns with circular sections (or concrete cylinders) is developed via the above theoretical model. By introducing the corner radius ratio ρ , a novel strength model for square concrete columns (or prisms) is further established. The proposed peak stress models are in good agreement with the experimental data covering the range of cylinder diameter D = 76 mm-610 mm, prism’s side length B = 100 mm-400 mm and the unconfined concrete strength f ’ c0 = 19.4 MPa-169.7 MPa. The established peak stress models are efficient due to the simpler expressions and high prediction accuracy.