Minimum Wall Thickness of Precast Environmental liquid Retaining Structures

[nader666]

Hi,

According to ACI 350-06 - 1.1.1.1, ACI 350 is not covering precast structures covered by ASTM except precast circular tanks.

AS per Chapter 14 , the minimum wall thickness is 12" if the wall is 10 feet or more in contact with liquid but for conventionally cast in place walls.

I just gussing that it stated cast in place because precast structures are not covered by ACI 350 but it is only covering precast circular tanks.

I just wanted to know if the minimum wall thickness of precast structure that has more than 10 feet liquid should be 12" ?

Thank You

 

[JedClampett]

I'm trying to think what problem you're trying to solve here? ACI 350 is concerned with watertight environmental structures. What kind of watertight structure can you make with precast? Besides prestressed tanks, the only other thing I can think of is manholes or vaults, which are not watertight, just leak resistant.
Besides, if you're making some precast structure with 12 inch walls, it's going to weigh a lot pretty quickly. A 10 x 10 wall weighs 15,000 lb.

 

[nader666]

It is not a manhole, it a grease trap that retains liquid all the time. The bottom section of the structure that retains the liquid is monolithic.

 

[TehMightyEngineer]

I've designed precast 350 sections that were for a combined sewage and stormwater overflow system. We used 12 inches (or greater) for the taller vaults that had to be water tight and the interior was lined with 3mm HDPE GSE studliner and the outside was damp-proofed with 2 coats of sealant.

Maine EIT, Civil/Structural.