footing steps

[struct_eeyore]

Hi all,

Can anyone provide some guidance on how closely continuous footing steps can be placed? I have a retaining wall that's going from retaining 15ft of soil to retaining 3ft, with the change happening over a distance of ~ 100'. I will be maintaining 2' of soil over the toe throughout. Is 8' legitimate? Could I bring the steps in further to say 3'? Thanks!

EDIT: forgot to ask, how tall can a single step be made?

 

[BridgeSmith]

What type of wall is it? If you don't have something dictated, sounds like a job for a block-faced MSE (Keystone, e.g). With those, the steps are in increments of 8" in height and at half increments (1.5, 2.5, 3.5, etc.) of the 18" block length for intermediate steps of 8", 24", 40", etc. (Draw it up with a running bond pattern and you'll see it)

 

[bridgebuster]

I don't know of any code provision; Rule of thumb: minimum 8 to 10' on rock; minimum 10 to 15' on soil.you could try 4 panels @25' long with a 3' step. If your footing is CIP concrete try to keep the steps between 2 to 3'. Steps more than 3' tall typically need construction joints.

 

[KootK]

- To an extent, this may depend on what your geotechnical report says.

- For regular, building exterior strip footings, I see a lot of 1V:2H effective sloping (by way of stepping), and a max individual step of 4'.

- Certainly, I can't see 8' being a problem. Obviously though, you want to be stepping as fast as possible to save costs where you can.

- For a cantilever retaining wall, I'll tend to spread out my steps further than I would with a non-cantilever retaining wall. The reinforcing is more complicated for a cantilevered retaining wall footing than it is for a generic strip footing. As such, I think that it's a bit cruel / costly to be asking for very tightly spaced steps, no matter what the GC might think initially. And doing so would likely invite QC issues as well. I try to maintain straight runs of unstepped footing of at least 3X the width of the retaining wall footing. That just feels reasonable to me in many instances. It's not a hard limit for technical reasons or anything like that.