Tremies

What is the longest tremie I can build?

Let us consider the example of an 8" diameter watertight tremie, to be used underwater, with no divers below.

The possibility exists that the entire tremie could quickly become filled with concrete, because:

1. The discharge end of the tremie will be submerged in concrete.
2. There is no visual inspection of the disharge end.
3. A concrete pump truck can fill a tremie section in seconds, due to the tremie's small volume.

Consequently we will calculate for this worst case scenario: a tremie filled with concrete.

Step 1. Calculate the Volume of a Single Tremie Section:

The volume of a 13' long by 8" dia pipe is:

= Pi x r² x height in inches x 1 ft³/1728 in³

= 3.14 x 16 in² x 156 in x 1 ft³/1728 in³

= 4.5 ft³

Consider that a concrete truck could feed concrete into the tremie at a rate of approx. 50 ft³/minute (2 yd³/minute).

Step 2. Calculate the Weight of a Single Tremie Section Filled with Concrete:

The weight of a 13' long by 8" dia pipe is 65 lb.

The weight of the concrete in the pipe is calculated as follows:

= pipe volume x concrete density

= 4.5 ft³ x 150 lb/ft³

= 675 lb.

Therefore the total weight is 740 lb. per filled tremie section.

Step 3. Calculate the WLL:

The Working Load Limit (WLL) of the system is calculated as:

= Breaking strain ÷ desired safety factor

= 20,000 lb. ÷ 3

= 6,660 lb.

Step 4. Calculate the Maximum Number of Sections that can be Linked:

We know that in a worst case scenario, a filled tremie section weighs 740 lb.

Therefore, the maximum number of tremie sections that can be safely linked together is:

= WLL ÷ the weight of a filled section.

= 6,660 lb. ÷ 740 lb./section

= 9 sections

Please call Superchute 1-800-363-2488 with any questions you might have.