Check for transfer forces at column base (pad and strip base:ACI 318)

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

Check for transfer forces at column base (pad and strip base:ACI 318)

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

Determinate the bearing strength of the column:

Φ*Pnb,c = Φbearing (0.85*f’c * Ac)

If

Φ*Pnb,c < - Pu

Then check fails

Else determinate the bearing strength of the footing:

Φ*Pnb,f = min [√(A2/Ac), 2] * Φbearing (0.85*f’c * Ac)

where for rectangular columns:

A2 = min {Lx , 2tftg + lx+ min [(Lx-lx)/2 - abs(ex), 2tftg]} * min {Ly , 2tftg + ly + min [(Ly-ly)/2 - abs(ey), 2tftg]}

Note:

Circular columns are treated as square members with the same area.

If

Φ*Pnb,f < - Pu

Then check fails

Required min. area of dowel bars between column and footing is then:1

As,min = 0.005*Ac

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

As,min > As,prov,column

Then check fails

  

Footnotes

1 ACI 318-08 Section 15.8.2.1
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