Concrete column pour stop 2

[StrEng007]

Where do I find information regarding a concrete column pour stop, proper practice, detailing, etc.
Is it contingent upon bar placement?

1. Between the time when a truck runs out and the next truck arrives.
2. Between intentional stops in construction.

 

[StrEng007]

After reviewing several concrete text books, most of the recommendations are leave dowels extended through cold joint. Also, making sure the cold joint is clean and prepped for adequate bonding of the next pour is essential. Besides that, not much on the actual considerations I need to make regarding location/placement of these joints. Also, nothing regarding how this impacts the design, if there is any reduction to be taken into account.

I've never had to stop a beam pour, but this whole topic now has my interest regarding long beam/column pours. Theoretically, you'd want to stop a beam at its location of maximum moment and low shear.

 

[BulbTheBuilder]

For a column pour stop, I expect the joint to be horizontal. But for a beam pour stop, are you talking about horizontal or vertical? From your last statement, I presume you meant vertical joint. Doesn't a detailing for construction joints take care of your situation? Or your problem is more of an "unexpected" construction joint during concrete pour?

 

[BAretired]

A column should stop at the underside of slab. Sometimes the contractor extends it an inch or so above the underside of slab: that doesn't hurt the column, but it creates a punching shear problem for the slab.

If the joint is a result of an unexpected stop during the pour, it should preferably be located so that the rebar on each side of the joint can be fully developed. It would be best to leave a roughened surface at the joint.

 

[Lomarandil]

Bulkheads to create a vertical joint in an interrupted beam placement are really a pain for the contractor. As BA points out, the location should be chosen to permit full development of the main beam bars. If you're planning it in advance, diagonal stirrups can be placed at the interface to help the shear transfer.

If a beam placement really must be interrupted, a horizontal joint is possible and doesn't necessarily require special detailing or preparation. If planned in advance, it may lead the designer to choose smaller, more frequent shear reinforcement to make sure those bars are positively developed across the joint.

 

[atrizzy]

BA, this is why I always specify the column pour stop to be 1" below underside of slab.