large bridge column supported by drilled shaft
large bridge column supported by drilled shaft
(OP)
Have a larger than required bridge column that is to be supported by a single drilled shaft. The problem is that the least dimension of the column is slightly too narrow to simply extend the bars from the drilled shaft into the column. As a side note, both the column and drilled shaft has plenty of capacity. My idea is to support a drilled shaft cap on top to hook the bars that won't fit in the column and extend the bars that will into the column a development length. Then I have hooked dowels from the column extending into the footing/ds cap. My question is this...what forces do I need to design the footing/ds for? It seems like there is really nothing much required to be carried by the footing. See attached. Any help is appreciated.






RE: large bridge column supported by drilled shaft
The pile cap must be deep enough to develop any bars occurring outside of the pile area. In that case, a simpler detail might be to cut off all of the pile reinforcement 2" below top of pile cap and provide dowels for all of the column steel. The column may need more ties than you have shown.
Pile cap reinforcement would likely consist of nominal ties as the cap seems to be in compression throughout.
BA
RE: large bridge column supported by drilled shaft
There is some flexure that needs to be transferred from the column into the drilled shaft....breaking forces, wind, etc. But I don't think any of that flexure is really needed to be carried by the footing itself.
I had intended to detail with some nominal reinforcing as you suggested...just need a second set of eyes. Thanks for the input!
RE: large bridge column supported by drilled shaft
Another consideration is definition of mass concrete. By arbitrarily increasing the column, you may be leading the contractor into the requirements of mass concrete placement.
Regards,

Qshake
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RE: large bridge column supported by drilled shaft
BA
RE: large bridge column supported by drilled shaft