PVC Bolt Sleeve for future Anchor Bolt 1

[WildCard09]

I have a concrete pedestal, which will hold a 18 foot W14x68 column. Due to unusual circumstances, this pedestal must be cast in place but not with its 4 anchor bolts. The 1 1/2" x 34" anchorbolts (28" into concrete) will be installed after the pedestal has been cast, column is in place and temporarily secured.
I'm thinking of casting the pedestal with PVC pipes in the location of the future anchor bolts, this will allow me to leave a penetration in the pedestal to install the anchor bolts afterwards. But im not too confident I will be able to pull out the PVC after the concrete hardens and before installing the bolts. Any ideas guys?

 

[paddingtongreen]

A method that we used to use when heavy vessels and stacks were to be supported, was to embed an assembly that allowed us to place the bolts after the equipment was in place.

From the bottom:
a plate;
a short piece of pipe welded to the plate;
a plate, large enough to be the anchor plate, drilled with a heavy nut welded to the bottom of the plate, welded to the pipe;
a long piece of pipe, welded to the plate, with the top, level with the top of the concrete. We packed the top with rags to stop concrete getting inside.

The stack was put in position, leveled on shims, the threaded rods inserted and screwed into the bottom nut until they hit the bottom plate. The top nut was snugged and the grout was dry packed. Now you would use flowable grout.

It sounds expensive, but you easily save more money in field costs.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[Ron]

Michael...nice method!

WildCard09...you can lightly grease or oil the sleeves, but I would make the sleeves smaller and then drill out afterward by just running a chase bit down the hole to remove and grease or oil residue. You can also use a variety of tools to roughen the inside face of the hole (a brake cylinder hone for instance...flexible and can be put on long shaft).

If you use the method your thinking about, keep in mind you have no positive anchorage at the bottom of the bolt, so you're depending completely on side bonding...with that in mind, I hope your depth of embedment is sufficient to compensate.

Using Michael's method will give positive anchorage at the bottom of the bolt and allow you to mobilize stress resistance in the concrete as it should be.

 

[doka1]

There are corrugated plastic sleeves that you could leave in. They are commonly used as inserts for connecting precast to cast in place concrete.

 

[Ron]

doka1...I believe those anchors are primarily for shear transfer...not direct tension as with a foundation anchor bolt.

 

[paddingtongreen]

I was just thinking, there was a ploy we used once when we inserted an additional column to an existing building. We put in the base with the dowels, then the rebar cage and formwork; hung the column from the steel with the anchor bolts on the baseplate, then we placed the concrete.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[JedClampett]

If I understand paddington's idea, here's a manufacturer that makes a product that's similar.

http://www.decomfg.com/media/deco-heavy-duty-adjustable-anchors-sales-sheets.pdf

 

[lsmfse]

There are others as well. I've attached a picture of one we used in the past(I cant remember the manufacturer)

 

[JedClampett]

That's a Richmond form saver with a threaded end.

 

[lawayosh]

Precast piles have seen rebar dowels (pourable cement or epoxy) grouted into sleeves of material similar to metal flex conduit. The spiral convolutions of the flex and rebar deformation provide resistance to pull-out.

Yosh