Rebar at same height in beam to pile cap connection 1

[ChiEngr]

Hello,

I have designed a grade beam and pile cap foundation system and am wondering how you guys generally address the issue of top and bottom rebar in the beams/caps from clashing with each other. Do you adjust the cover on the members? Or do you expect the fabricator to slightly bend the bars at the intersection of the two members? I am not sure if the latter is allowed by ACI, but I think that would be the simplest option.

 

[TLHS]

Are the bars in the cap parallel to the beams? You can generally just have them run beside each other in the same layer unless your beam bars are really tight.

If that doesn't work for whatever reason, I'd run the beam bars as a lower top layer and upper bottom layer (i.e. inside of the pile cap beams). I might consider jogging those back out for the main beam portion with a specifically detailed lap or a bent bar.

 

[hokie66]

My pile caps are always deeper than the grade beams. That takes care of the bottom bars. The top bars in the beams are normally more important, and run through the pile caps. If the pile caps must have top bars, place them below the beam bars.

 

[HTURKAK]

I would understand for the GRADE BEAM , perimeter beam and the top level should be higher than the top of pile cap .The top reinf should be continuous and bottom reinf. should be projected inside pile cap without clash.
If this is tie beam, the top and bottom reinf. should be continuous for intermediate caps .

The excerpt is from Manual for Detailing Reinforced Concrete Structures to EC2 ( by J.CALAVERA)

Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[JAE]

I'm not sure I'm understanding what you mean by "cap top and bottom bars".

Usually a cap over a pile is reinforced more like a column, with vertical bars and horizontal ties.

The conflict usually arises when the horizontal beam bars conflict with the vertical cap bars as well as vertical pile bars (if any). This is usually remedied by simply moving the beam bars laterally if there is room, or adding shorter horizontal bars through the cap to create the necessary tie-in to the beam and splicing them with terminated beam bars.

Is your condition something different than this? Perhaps a sketch?

 

[dik]

In these environs, the pile cap would not normally be part of the grade beam.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[ChiEngr]

JAE,

I have a pile cap supported by typically 3 or 4 helical piles. Because I am in SDC C, the Code requires that my caps are tied together with tie (grade) beams. My typical pile cap reinforcement is a cage of rebar, say #6 at 9" top and bottom in each direction with the bars being hooked and lapped along the sides of the pile cap. My issue is that the grade beams are the same depth of the pile cap, and the grade beam reinforcement has the same cover as the pile cap reinforcement. So I am left with one of two options, shifting the the pile cap reinforcement inwards so that the grade beam reinforcement can run through the pile caps, or having a slight bend to the grade beam reinforcement so that once the bars reach the pile cap interface, they can miss the pile cap reinforcement. I am not sure if the latter is a viable option.

Also, the grade beams are supported on intermediate piles along their spans (for the long span beams). The piles are embedded 6" into the grade beam and I have specified 3" additional clear cover from the top of the pile. This gives a total of 9" of clear cover technically speaking for the grade beam bottom reinforcement. If you try to ensure that your longitudinal bars do not exceed the code mandated max spacing, you will see with that amount of cover that your calculation will yield a negative answer (15 - 2.5*cover ... assuming fs = 40 ksi). Any thoughts on this?

 

[TLHS]

Can you just run them both at the same level and shift the cap bars as required to fit them into the same level? How dense are your bars?