Calculation of Capacity against Shear based on ACI 440/ACI 318
Unstrengthened Members
The shear capacity of reinforced concrete members is calculated from the equation (22.5.1.1) of ACI 318-19
with the shear strength provided by the transverse reinforcement Vs computed from equation (22.5.8.5.3) of ACI 318-19
and the shear strength provided by concrete Vc computed by the table22.5.5.1 of ACI 318-19.
Users are advised to refer to the relevant publications for the definition of the other parameters and further details on the expressions.
FRP strengthened Members
The design shear strength φVn of a concrete member strengthened with FRP should satisfy Eq. (13.5)
Where φ should be per the design standard used for the rehabilitation and Ve is the design shear force.
The shear resistance Vn, may be calculated from expression (10-3) of ASCE 41-17 for columns or the equation (22.5.1.1) of ACI 318-19 for beams adding in Vs the contribution of the FRP jacket to the shear resistance namely Vf.
The contribution of the FRP jacket to the shear resistance is computed through the following expression multiplied by a reduction factor ψf, as described in section 11.4 of ACI 440:
Where:
and
The total shear strength provided by the sum of the FRP shear reinforcement and the steel shear reinforcement should be limited as indicated in the equation below:
Where Vs is the strength provided by the steel reinforcement and is calculated according to the section 22.5.8.5.3 of ACI 318.