diagrams for out-of-the-ordinary Column Dowel pattern

[boffintech]

Am inspecting on job right now where a number of the columns have an unusual column dowel arrangement.

See attached shop drawings. Note that the shops incorrectly show the D-D cut at both the bottom and top sections of the column. I think cut D-D only applies at the botom section of the column where the elevation view shows the dowels inset.

The EOR says that the inset is 1 foot.

A) Why dosen't ACI-318 12.14.2.3 — Bars spliced by noncontact lap splices in flexural members shall not be spaced transversely farther apart than the smaller of one-fifth the required lap splice length, and 6 in.

B) Any idea what forces would require this sort of dowel arrangement?

And dumb the answers down so an inspector can understand them

 

[slickdeals]

Does the column become smaller in the floor above? If that's the case, then maybe he is developing the starter bars one floor below?

 

[boffintech]

No change is size. The column is 4'6"x6' from top to bottom.

In addition to supporting the roadway, this column supports a steel column that is part of a large canopy at the entrance of an adjoining structure. Vehicles on the roadway may stop and drop off/pick up passengers.

 

[hokie66]

Looks like he is tired of footing starters being cast outside the column, so he is showing them well inside. With an assumption of a pinned column at the footing, and without the need to develop the column bars at that level, it probably doesn't matter.

 

[slickdeals]

It is interesting that you bring up a pinned-base column.

Do you know what the requirements for spacing between non-contact lap splices are for a compression member? I looked in ACI but did not find any thing except the one that boffintech quoted. I don't think that non-contact lap splices should be further than 6" in a column, unless there is some variance in the code

 

[hokie66]

I didn't say the column base is pinned, but I imagine that is the design assumption. Nothing wrong with that.

If the column works in bearing at the footing, the starter bars are just nominal, not required to be lapped.

All speculation, as only the designer knows how the column works. An inspector cannot decide for himself to change things.