How to suppor cabling in prestressed concrete building?

[wus2000]

In a building with prestressed concrete, I want to use unistrut channel and all threaded rod to support conduit and cable tray. But the structure engineer said they will use prestressed concrete, and I can't drill on the floor or wall. They will bury steel plate into the floor, and the hanger will be sealed to the steel plate.

I want to know, under this condition,
1, Can I drill on the floor or wall?
2, Can the unistrut system be used, how to connect it to the structure of the building? By seal, beam clamp, or anchorage？ I'm wonder if there exist beam in this type of building.
3, If the steel plate will be buried, we have to make sure where to place the hangers at the first stage. If we change the place, how to connect it to the structure?

 

[cadpoint]

I've seen kenduorgh(sp) just layed on the form and tie-wired, the open side was facing down and was sealed both sides with duct tape.

You can also use any search engine and use any of combination of terms; "threaded, precast, unistrut, hilti - concrete inserts".

The only problem is that you have to have the engineer sign off on any lay out, and also approve the arrangement for inserts for larger conduits if required.

 

[TxShocker]

The only problem is that you have to have the engineer sign off on any lay out, and also approve the arrangement for inserts for larger conduits if required.

This is the big thing that you need to make sure you get in writing.

 

[wus2000]

It's true. But anyone has met this problem before?

 

[jeremysterling]

In the past, we've used the "Wood Knockers" for post-tension slabs:

http://powers.powers.com/_cleanup_scott/promo/Bang-It_WoodK Product Data.pdf

 

[weressl]

In a building with prestressed concrete, I want to use unistrut channel and all threaded rod to support conduit and cable tray. But the structure engineer said they will use prestressed concrete, and I can't drill on the floor or wall. They will bury steel plate into the floor, and the hanger will be sealed to the steel plate.

I want to know, under this condition,
1, Can I drill on the floor or wall?
2, Can the unistrut system be used, how to connect it to the structure of the building? By seal, beam clamp, or anchorage？ I'm wonder if there exist beam in this type of building.
3, If the steel plate will be buried, we have to make sure where to place the hangers at the first stage. If we change the place, how to connect it to the structure?

The fabricators of the pre-stressed concrete elements usually have a variety of examples of acceptable support methods with weight and dimension limitations. I would go back to them.

 

[satcom]

The fabricators of the pre-stressed concrete elements usually have a variety of examples of acceptable support methods with weight and dimension limitations. I would go back to them.

It is ok to talk to the engineers, you can usually get a lot of good information and direction from them.

 

[wus2000]

The fabricators of the pre-stressed concrete elements usually have a variety of examples of acceptable support methods with weight and dimension limitations. I would go back to them.

Do you have the examples?

 

[renosteinke]

I've got limited internet access at the moment - so I can't do the searching myself .. BUT....

I'll bet there's some manner of trade association for pre-stressed concrete, and that their site has all manner of helpful information.

 

[wus2000]

In the past, we've used the "Wood Knockers" for post-tension slabs:

http://powers.powers.com/_cleanup_scott/promo/Bang-It_WoodK Product Data.pdf

Thanks for your reply. The "Wood Knockers" is an insert which should be secured on the wooden form before the pouring of concrete. But at the time of pouring of concrete, the shop drawing work of electrical hasn't been finished. So how can I determin the detailed position of the "Wood Knockers" at that time?

 

[mancenanee]

Thanks for your reply. The "Wood Knockers" is an insert which should be secured on the wooden form before the pouring of concrete. But at the time of pouring of concrete, the shop drawing work of electrical hasn't been finished. So how can I determin the detailed position of the "Wood Knockers" at that time?

Usually, you should finish the electrical shop drawings before the pouring of concrete. So you can determine where you need the wood knockers that time.

 

[stevenj76]

What's the difference between pre-stressed and post-tensioned concrete?

 

[LarryFine]

What's the difference between pre-stressed and post-tensioned concrete?

It's kinda like the difference between marrying someone who was already stressed out and someone who got that way after marriage.

 

[masterinbama]

What's the difference between pre-stressed and post-tensioned concrete?

Pre stressed is generally fabricated in a factory and shipped to the site and set with a crane. (Think bridge support beams and hollow core slabs.) The fabricator has to give you acceptable drawings to where you can and cannot drill and anchor.