Toe projection in Basement wall

[brick2020]

Hi all,

Is it a normal practice to give a toe projection in basement walls.

I have 4 level basement wall, the raft/footing for the baement wall is 750mm. When i run the safe analysis, the edge stresses are not very high.

Whatis the minimum projection of the toe in a basement wall? Is there any standard ACI practice?

A consultant is proposing a projection of 3ft, which i think is excessive, i would like to push for 100mm(4"-6" at most)

any thoughts or references , plz ??

 

[JedClampett]

I like to extend foundation walls about 1'-0" when I can. If you have wall hooks from the vertical reinforcing and slab hooks from the horizontal, it seems that there will be a lot of congestion without the projection (I design the base as fixed). Plus for the horizontal steel, you need a length of bar (ldh) beyond the hook to develop its capacity. Hopefully this can be done in the slab thickness for the verts.
I wouldn't put a lot of faith in some computer analysis for this corner. What I've seen is that the analysis overestimates the support effectiveness and under estimates the stresses.

 

[msquared48]

The minimum projection is about 4" - enough for the formwork for the wall.

Depending on the wall size, my normal footing width is 14" to 18" for residential and 24" to 30" for commercial.

Mike McCann
MMC Engineering

 

[crcivil]

25%-30% Toe
70%-75% Heel
of total footing width

I read it somewhere. Regards.