Anybody seen a modular block wall made of these things? 3

[beej67]

(see attached photo)

Looks like about a six foot long precast curb with holes hollowed out of the middle to reduce weight. Then they have a bell end so you can fit one in the other. No sort of tieback, and no way to connect an upper course of them to a lower one in a retaining wall. This wall was built in the early 80s, by stacking these things on top of each other and backfilling.

Any idea what these things are called?

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[dgillette]

Nope. Registers 6.3 on the weirds---ometer. My guess is that they were designed for something else entirely, but used here because they were available for cheap. They don't appear to have been very successful in this application.

Any chance those holes are intended for post-tensioning?

DRG

 

[CarlB]

They look like utility duct banks. Utiliducts? Such as for communication lines.

 

[beej67]

Post tensioning is definitely a thought, although it could just as easily have been to keep the weight of the members down.

The photo I linked was probably the worst looking spot in the area, but none of it looked great. It also abutted a creek, so there's some undermining in places due to scour. I suppose it's not a terrible operational service life if it went in in 1980, but I wouldn't build with them. I'd like to know what the heck they are to reference them in a report I'm drawing up though. Maybe it's worth a crosspost to the structural forum?


Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[beej67]

Duct banks are another good idea.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[PEinc]

I guess they don't work very well as a retaining wall.

http://www.PeirceEngineering.com

 

[dgillette]

I like CarlB's hypothesis.

 

[concretemasonry]

Carl is spot on regarding what they were originally made for.

Probably rejects or second that were solid/used for another purpose. Usually, the manufacture marks then as rejects or similar to insure they are not drawn into future liabilities.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[PEinc]

Well, with all of the duct voids, they don't make a very good gravity wall.

http://www.PeirceEngineering.com

 

[mherr78]

Are they concrete beer can holders?

 

[concretemasonry]

Some sizes (core diameter) can work well if the mass of concrete is chilled.

Since they are about 24" long, you have to pick up one end of the duct to slip some cans out. Magnets do not work on aluminum cans, so you have to rely on gravity.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[sixaparrat]

Yep definetly 6-way cable ducts

Cheers,
Chris

 

[DirtPusher]

These are used in my part of the country as utility duct banks
for running multiple utilities (elec, tel, fiber optic, cable tv etc.)
in one trench. These look like they were not used as a retaining wall,
just left over from previous work or a project that never got passed the product delivery stage.

 

[DirtPusher]

Follow-up.
It appears that the duct bank design depicted in your posted
image is no longer being produced. At least I could not
find any precast concrete company still producing that particular style.

View the video to see the new-improved (watertight)
styles.

http://www.youtube.com/watch?v=hSstMrOWJdc

 

[brickmason]

are they clay units? they almost look like flue tiles but not quite. they would be stacked verticlly on end if so. no way can they be meant for a retaining wall

 

[bridgebuster]

Now I have

 

[beej67]

How about that.

What year was your wall constructed, Buster?

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[bridgebuster]

Beej - I really couldn't tell you; maybe somewhere between 10 to 25 years ago. It's alongside a bridge I was inspecting. The bridge was built in 1917 then rehabbed in the 1980's. At one corner of the bridge is a bus garage that was built about 10 years ago. This duct bank wall is an extension of a retaining wall in front of the garage.

We now know that duct banks don't make good retaining walls.