Shear between web and flanges: the transverse reinforcement per unit length Asf/sf and crushing of the compressive structs in the flanges
Eurocode 2 part 1-1: Design of concrete structures 6.2.4 (3)
• The transverse reinforcement per unit length, Asf/sf, may be determined as follows (see Figure 6.7):
|(Asf⋅fyd / sf) ≥ vEd⋅hf / cotθf||(6.21)|
- is the longitudinal shear stress at the junction between one side of a flange and the web. It is determined by the change of the normal (longitudial) force in the part of the flange considered:
vEd = ΔFd / (hf⋅Δx) (6.20)
- the thickness of flange at the junctions
- the length under consideration.
The maximum value that may be assumed for Δx is half the distance between the section where the moment is 0 and the section where the moment is maximum. Where point loads are applied the length Δx should not exceed the distance between point loads
- the change of the normal force in the flange over the length Δx.
- is the angle between the concrete compression strut and the beam axis, see § 6.2.4 (4)
- is the design yield strength of the reinforcement, fyd = fyk/γS,
see § 18.104.22.168 (1), § 22.214.171.124 (2) for the values of γS,
see § 3.2.2 (3)P for the uper limit of fyk,
see Figure 3.8 for the design stress-strain diagrams of the reinforcing steel.
• To prevent crushing of the compression struts in the flange, the following condition should be satisfied:
|vEd ≤ ν fcd sinθf cosθf||(6.22)|
- is a strength reduction factor for concrete cracked in shear, the recommended value of ν is ν = 0,6(1 - fck/250) (Expression 6.6N in § 6.2.2 (6))
- is the design compressive strength of concrete, see § 3.1.6 (1)P.
This application calculates the reinforcement per unit length Asf/sf from your inputs. Intermediate results will also be given.