2x2 Footing Step Exceeded

[CANeng11]

The contractor for a new house stepped footings for a garage built on a slope. The footings were stepped with 2' x 2' steps until at the end of the wall he did a large step of 42" deep. Obviously this doesn't meet code and he is wondering what can be done now. There isn't much load on this wall, no floor or roof, so just a bit of dead load really. Is there any remedy for this situation?

 

[Ron247]

What code are you using?

 

[JoelTXCive]

Could you provide a diagram/picture? A hand sketch or anything would help.

 

[CANeng11]

I'm using the National Building Code of Canada. See the attached sketch I did very quickly. I can provide more detail alter if required.

 

[KootK]

Engineer the last step as though the wall were spanning over the soil rather than resting upon it. This is where you get to you use that P.Eng stamp for good rather than evil.

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[msquared48]

ABBA kadabra... poof! Problem gone!

Mike McCann, PE, SE (WA)

 

[CANeng11]

Problem is it is already built.

 

[Ron247]

Would installing helical anchors cure the issue. I am not familiar with the Canadian codes.

 

[CANeng11]

The specific code reference I am referring to is 9.15.3.9 which states:

"Where step footings are used, the vertical rise between horizontal portions shall not exceed 600mm and the horizontal distance between risers shall not be less than 600mm."

 

[KootK]

My solution assumed that the footing was already built. Does it not calc out?

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[BAretired]

If the sketch is drawn to scale, some parts of the foundation appear to be too close to grade level, leaving questionable protection against frost heave. That could be addressed with added insulation.

Problem is it is already built.

Do you know if the wall is reinforced?

BA

 

[Ron247]

Sounds like you can't build stepped footings on a hill steeper than 45 degrees unless the thickness of the downhill footing increases with each step to maintain the max 24". That would look strange. I am not familiar with a similar clause in the IBC unless I have missed it over the years. I do not think I have built in one that steep yet.

 

[atrizzy]

Part 9 of NBCC is prescriptive. If the foundation wall is reinforced such that it spans from upper footing to lower footing, ignoring the intermediate 'step' footings as Kootk suggested, and that the bearing pressures on the two 'support' footings are acceptable, this seems like it should work.

 

[Ron247]

Related to this post, is there a concrete column that connects the footings at each level to each other so there is a continuous concrete column and beam system or are the footings at different elevations independent of each other. I always connect them but I have seen numerous foundations where they are not connected at all to each other. I also find a lot of differential settlement and therefore cracks at the steps.