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Need foundation cage help.

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I need to get an answer to this question as quickly as possible and I am
currently subscribed in digest format. If anyone can help, could you
possibly email me a response directly at structures(--nospam--at)

I designed a framed patio cover on four columns (TS6x6x1/2") that were
originally designed to be embedded into a 24" square x 48" deep post
hole foundation. The patio cover (designed with an R=2.2) is 14'-0"
above the ground and roughly 35' x 14'. The lateral load to each column
is 1-Kip and the gravity load is 2-kips for the dead load and 2 kips for
the live load reactions. I've designed the foundation to be placed with
a 12" thick erection pad first - to which the column and base plate will
be secured on dry pack. The remaining 3'-0" plus a 6" pedestal (to
prevent water from flowing from the patio into the steel.

The contractor now wants to fix the column to the pedestal rather than
embed them - the steel is too heavy to manipulate. The design of the
foundation does not change as fixity was assumed at the surface or
14-feet from the load application. I ran the plate and ended up with a
12-inch square by 3/4" thick base plate w/ (4) 1-inch diameter A307
anchor bolts (I have not confirmed the tension on the bolts as yet).

My question is that I know I will now need a cage in the foundation
which was not required when embedding the steel. Can anyone recommend a
standard cage configuration that might be acceptable for a 14 ft-kip
moment at the base plate? Is there a standard - prescriptive method for
sign post foundations where the fixity occurs at the top of the deep
foundation? Is there an online reference or calc than anyone can provide
to guide me on this design?

Any help would be greatly appreciated. Please send responses privately
as I won't receive the digest until late tonight and need to advise the
contractor this afternoon.


Dennis S. Wish, PE
California Professional Engineer
Professional Forum:

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