Design of caisson footing w/ partially embedded column

[ruready]

Anyone done this before? We don't want to extend the column to the bottom of the footing but need a way to calculate how the moment in the column dissipates in the footing relative to the embedment and how to reinforce the remaining concrete if needed. Thought of subtracting the resulant from the passive pressure below the bottom of the column from the moment and doing it that way. Anyone know of any books, etc. Thanks

ACI 318-05 specifically states in 1.1.5 that it does not govern the design of caissons (unless high seismic zone). Tried finding anything on the literatue that they refence with no luck and couldn't find anything in any books we have or on the internet.

 

[rtamaccio]

looking for the same info myself, did you ever find any good resources?

 

[ruready]

No, we didn't. Just came up with our own stuff. Did it the way I described above. Doesn't really work well if your footing is not constrained. We just dissected the equations for caissons in the ibc. Sized the footing. Calculated the moment at the bottom of the pole based off of the passive resistance at that depth and sized any reinforcing accordingly. We welded the bars to the post and extended them to the bottom of the footing. Obviously we through in a lot of conservative values and member sizes, etc. We do carports and our clients do not want to extended the posts to the bottom of their 5' to 7' deep footings.