Bending Stirrups Around In Place Grade Beam

personalt

My engineer was out inspecting a grade beam we did and because of some issues with pile placement my engineer wants me to add a few extra stirrups however the grade beam is already in place.

The stirrups are made out of #4 bar. If I were to leave one of the bends open is there a way I could make the last bend in the pit

My thought would be if I could prebend it like below, I could then bend it at the * and the part above the * would be become the top and the top would become the right side.

Is it realistic to be able to bend #4 rebar with only an 18 inch peice to push on? Is there a tool I can use to bend it while already in the hole?

I could make it out of two pieces I think but I was hoping to make it out of one..

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jmic

Per,
How about heating it up with a torch, then easily bend it however you need to with a pc. of steel pipe.

__________________
___"Remember You Never Get A Second Chance To Make A First Impression"______________________
Joe

handyman923

I would use a 2-piece tie with a U-shaped main tie with 135 deg hooks at each end. And then cap it with a piece with a 90 deg hook one end and a 135 deg hook the other end. Then alternate the 90 and 135 deg hooks. I would run this by your engineer...

Tscarborough

The purpose of a tied stirrup is just to hold the bars in the proper position until the beam is poured, so I don't see an issue with using straight bars, unless you have a complex design using tensile bars in oblique patterns to reduce cracking. To my knowledge, that has not been done for the last 50 years or so.

Stirrups are used to make building the cages easier, that is all.

handyman923

Stirrups are not merely used to hold the longitudinal in place. Stirrups are used to resist shear forces (resist diagonal shear cracking). If your engineer is wanting you to add stirrups around the pile, there is probably a reason. Shear forces are higher over piles. I would ask your engineer to be sure. I could be wrong...

K2

I don't think torches are allowed to be used for bending rebar or am I thinking of something else??

Tscarborough

You are not wrong, Handyman, but that effect only applies if the entire beam is designed as such. I have not seen one designed that way in a long time, and certainly not in residential construction, ever.

ch0mpie

yes handyman stirrups are used to resist shear forces. Shear forces occur at beam supports (such as a pile or column) or where there is a large concentrated loading on a beam. Since the length over which stirrups are required is based primarally on the span of the beam, my guess would be that your pile placement increased the span.

ch0mpie

What do you mean? There are two ways to increase shear capacity of the beam. Add stirrups or make the beam deeper.
I do however agree this is probably not an issue in residential as the loading is small enough to be handled by a beam of relitivally small depth.

Tscarborough

Dammit, you made me pull out my concrete engineers handbook. What is the current spacing, size of the beam, pile placement, and his requested spacing, as well as the bar size and location?

Tscarborough

What I meant was that for most residential applications, they are so over designed that the stirrups are, in effect, only to hold the cage in the desired position.

ch0mpie

sorry to make you think so close to bedtime (for me anyway)

Tscarborough

I lke to think (and pull out my reference books). Nothing I enjoy more than to be proven wrong or right, but mainly to help out.

ch0mpie

I wasn't even thinking that he was talking about a residential building when he said pile fndn, but I guess it could be the case. I was thinking piles=higher loadings

Thats what I love about this forum.

personalt

It is a 3 story residental. We are on crappy soil, that is the reason for the piles. The stirrups do as others stated give some kind of support, I think shear forces.

The beam requires more stirups near the end so they must do more then just hold the other bars in place.

The engineer allowed me to add the additional stirrups by making them out of two U shaped sections. We were allowed to make some small welds to hold it in place as it was too tight to get anything in there to tie it.

MC Excavating

I was working on a job in Bel Air, CA and the guys where using a bender sorta like this but a little different. Its small enough to work in the trench.

http://www.constructioncomplete.com/...llBender8.html



Here are photos of the job that they where bending bars on.





Click on an image and it will take you to my Photobucket gallery to view more photos.