Plastic Concrete Ties?

[AUCE98]

This is a picture of a concrete vault wall, 24-inches thick, 18 feet tall and below the water table. The plastic item in the middle appears to me to be plastic form tie of some sort, which I have never seen before. Some of these plastic items are hollow. Others appear to have some sort of plastic cap.

As you can see there is significant water intrusion at these locations. I am curious to know if any one has seen these before. I am going to direct the contractor to drill out and epoxy inject all these holes. Thoughts.

 

[Ingenuity]

Hard to tell from the photo, with all the leakage residue, but any chance it is an epoxy or polyurethane injection port or plug previously used to control leakage?

 

[BUGGAR]

Ditto Ingenuity.

 

[hokie66]

Probably unlikely for vault walls, but did this wall have some type of temporary soil anchors? In diaphragm wall construction, failure to seal the anchorage points adequately will cause that type leakage and staining.

 

[TehMightyEngineer]

In precast construction we often used plastic rebar supports but nothing like this that I've ever seen.

Professional and Structural Engineer (ME, NH)
American Concrete Industries

http://www.americanconcrete.com

 

[RHTPE]

In concrete construction there are 2 form tie applications that employ plastic:

1. PVC tie sleeves. Used with steel thru tie rods (15mm or 22 mm diameter). Often simply capped after form removal, sometimes plugged with an rubber 'stopper' inside the PVC sleeve. There are some more exotic sleeves that include an alleged waterstop plate near the middle of the wall - probably more common in Europe.

2. FRP form ties. Light duty approximately 1/4" diameter rods. Heavy duty approximately 1/2" diameter. I am unaware of any really effective waterstop that goes with this product.

Any other application involving plastic would likely be something the contractor would have dreamed up.


Ralph
Structures Consulting
Northeast USA