🕑 Reading time: 1 minuteFiber Reinforced concrete is used for concrete structural members for around thirty years and developed for both prestressed and conventional or ordinary reinforced concrete elements. Fiber reinforced polymer bars are used as reinforcement in these concrete. There are different types of fiber reinforced concrete with various properties for instance Glass FRP, Carbon FRP, and Aramid FRP reinforced concrete. The reinforcement bars of these polymers are manufactured with textures and surface deformation to enhance the bond between concrete and FRP bars. In this article, shear design of fiber reinforced concrete structural members is explained as per ACI 440.1 R-06: Guide for the design and construction of structural concrete reinforced with FRP bars code is followed.
Design Consideration for Fiber Reinforced ConcreteThere are various problems which are required to be accounted for shear design of FRP reinforced concrete members:
- The tensile strength of bent FRP bar is considerably smaller than that of straight portion
- There is no yield point in FRP and it has high tensile strength
- Modulus of elasticity of FRP is relatively low
- FRP has low transverse shear resistance
Shear Design of FRP Reinforced Concrete MembersFRP shear reinforcement design is based on strength design method and the strength reduction factor of 0.75, which is recommended by ACI 318-11 for decreasing nominal shear capacity of steel reinforced concrete element, is employed for FRP reinforcement as well. For the section under consideration, the ultimate shear force (Vu) has to be equal or smaller than the design shear strength.
Types of Shear Failure of FRP Reinforced Concrete
- Shear tension failure: controlled by rupture of FRP reinforcement.
- Shear compression failure: controlled by crushing of concrete.