Steel Forms Wall Spacer

[GreatDane2022]

Hi Gang-

Another wall question… we are using steel forms on this 13 foot wall and the foreman wants to use 1-1/2” PVC conduit around the taper ties because he is not getting the wall spacing in the middle of the wall. I am feeling uneasy about this but do not readily know why. I was going for an architectural finish as well. Thoughts?

 

[jjl317]

Assuming we are talking about concrete formwork, there are many wall systems (especially from Europe), that use form ties that utilize full length threaded rod with plastic sleeves that remain in the wall after the pour. Check out Peri formwork online, they have several variations, include some they say work on architecturally exposed finishes. I believe that most of these systems include special end caps, that help seal the ends, to prevent concrete leakage, and to allow for end plugs to be placed in the remaining hole after the forms are removed.

One benefit of these sleeved anchored when compared to taper ties is that they do help control the wall thickness (which can be a challenge with taper ties, which do not provide a positive stop).

If just PVC conduit is used, I am not sure how the ends will look after the pour, and how the holes will get filled. Plus if the PVC was placed over taper ties, I think they would want to wander around within the sleeve during the pour, which could lead to issues at the ends.

If I were in your shoes, I would check with my form supplier, to see if they might have a sleeve and threaded rod tie option designed to be used with the formwork system you are using.

 

[GreatDane2022]

Thank you jjl317!

It is the FormRight system by Dayton Superior. I am running to the local concrete accessories store to do some shopping this morning. I allowed the PVC on the middle two of the 4 vertical ties on the wall. I do have a portion of wall that has a form liner which will be “crushed” by the PVC so I am going to try to “pull out” the bow in the middle of the form by attaching horizontal 2x4 walers.

I am perplexed by this bow in a steel form. The forms are perfectly flat when on the ground, the bottom is against still plate, the top has a spacer tie…why isn’t the middle at the correct wall width… My engineering brain at work.

I do still like the steel forms but I have much experience to be had.

 

[jjl317]

If Formright is the system I am thinking of, its a clamp based modular system? I am guessing you are stacking multiple panels vertically?

All modular panels systems can struggle with maintaining flatness, even clamped systems. And over tightened taper ties can aggravate the situation. Switching to sleeve and rod can certainly help, and in some cases, adding additional clamps or even short walers across the joints can help in maintaining flatness.

Some reasons this occurs - concrete buildup on panel edges (preventing a good connection), worn / incorrectly installed / insufficient clamps, improper gang lifting.

 

[GreatDane2022]

Correct…9 foot panel with 4 foot panel on top. First time ever specifying and self-performing steel gang forms. Lots of rookie mistakes but all worth it especially if I plan to do more. I have very inexperienced crews too so we’ve been going at the pace of a geriatric scooter on low charge.

I can definitely see how the clamping setting could affect but how does the gang lifting play into?

 

[jjl317]

Most panel systems have limits on the height of a gang that can be lifted from horizontal (in some cases, dependent on which face is up), and exceeding it can overstress the clamps, leading to slippage.

And for what it is worth, in my experience, the term "steel gang forms" refer to exclusively steel faced gang forms (like Symons Max-A-Form), and not modular clamp systems like FormRight, which I believe is plywood faced.

 

[GreatDane2022]

Thanks for all the intel!