Check for transfer of horizontal forces by shear friction (pad and strip base:ACI 318)

Tekla Structural Designer
Modified: 2 Jun 2023
2024
Tekla Structural Designer

Check for transfer of horizontal forces by shear friction (pad and strip base:ACI 318)

This check applies when a concrete column is attached to the foundation.

Determinate if the shear-friction design method applicable1:

When surface is not intentionally roughened (conservative assumption)

If
Vu Φshear * Ac min(0.2*f’c , 800psi) for US units
Vu Φshear * Ac min(0.2*f’c , 5.5MPa) for metric units
where
  
Vu = max[abs(Fy,sup,u) , abs(Fx,sup,u)]

Then maximum shear transfer is permitted at the base of the column.

  
Required area of dowel reinforcement:
Avf = Vu / (fy * Φshear*μ)
where
μ =

0.6

when concrete not intentionally roughened (assumption)
μ = 1.4 when concrete placed monolithically

Currently dowel bars are not designed.

The area of the provided column reinforcement As,prov,column is the same as the provided reinforcement of starter/dowel bars.

If
Avf > As,prov,column

Then check fails

  

Footnotes

1 ACI 318-08 Section 15.8.2.1
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