D1.B.3.2 Design steps for Steel Beam with Web Opening
At the location of web holes, the capacity of the section is determined using the rules explained below.
Opening configurations for steel beams with unreinforced opening
Opening configurations for steel beams with reinforced opening
Section Properties Required:
- As = Cross-sectional area of steel in the unperforated member (at a section along the beam where there is no opening)
- d = Depth of beam
- tw = Thickness of web
- bf = Width of flange
- tf = Thickness of flange
- Z = Plastic section modulus of member without opening
- J = Torsional constant of the beam
- L = Length of the member
- Lb = Unbraced length of compression flange
Opening Information Required:
- e = Eccentricity of opening, specified using the HECC parameter (distanced from mid-depth of beam to mid-depth of the opening) = | e |
- sign convention for eccentricity: upward eccentricity + e, downward eccentricity - e
Loading:
- Vu = Factored shear at different opening locations
- Mu = Factored bending moment at different opening locations
Calculated Parameters
Circular Opening Properties:
Unreinforced Opening Properties:
- ho = Do for bending
- ho = 0.9 Do for shear
- ao = 0.45 Do
Reinforced Opening Properties:
- ho = Do for bending and shear
- ao = 0.45 Do
Tee Properties:
Refer to Figure 2.17(a), above
- st = Depth of top tee = d/2 – (ho / 2 + e)
- sb = Depth of bottom tee = d/2 – (ho / 2 - e)
Reinforcement Properties:
- Ar = Area of reinforcement on each side of the opening
- tr = Thickness of reinforcement bar
- br = Width of reinforcement bar
- Dr = Depth of reinforcement bar