Trench Calculator

VIDEO | Trench Calculator

The Trench Calculator allows you to quickly calculate trench, pipe, and bedding values. You can perform pipe-related take-off by defining the details of the trench (e.g., length, depth, width, hinge elevation, backslope, and swell factor), the pipe (diameter, elevation, and waste factor), and up to four beddings.

With this information, the Trench Calculator can automatically calculate:

Total excavation volume (neat-line)
Total excavation volume (including swell/shrinkage)
Total pipe to purchase
Lift Volume (for up to four beddings)
Lift Weight (for up to four beddings)

You can use these calculations to define certain cost item setup data:

You can use the Total Excavation Volume that is calculated as the quantity of the cost item
You can use the Total pipe to purchase calculation as the quantity of a resource (e.g., pipe) that has been employed to the cost item
You can use the Lift Volume or Lift Weight that is calculated as the quantity of a resource employed to the cost item in either cubic yards or tons
You can click the Toggle English / Metric button at the bottom of the dialog to switch between the English and Metric systems for entering data

You can access the Trench Calculator from the Actions tab of a Cost Item Record

When copying cost items in a job or from job to job, the Trench Calculator variable data is included with the data being copied. When a cost item is copied to the clipboard, Trench Calculator variable data is also included.

Trench Calculator – Trench Tab

The following steps walk through using the Trench Calculator to take-off excavation volume.

Step by Step — Trench Calculator – Trench

Open the Training Job and from the Estimate tab, select Cost Breakdown Structure.
Create a new cost item from the bottom row of your CBS and call it 24” Pipe.
Add the following three subordinates and update their Units of Measure:
- Excavate Trench: CY
- Install Pipe: LF
- Backfill Trench: CY
Open the Excavate Trench Cost Item Record. Add the following resources:
- LL2 Laborer – 1
- LO2 Operator Class 2 – 1
- EX245 Excavator 245 – 1
Adjust the Production to: 100 CY/Hour.
On the Cost Item Record’s Actions tab, select Trench Calculator.
For Trench Length, type 1000.00 feet.
For Trench Width (at the bottom) type 4.00 feet.
Enter a Trench Depth of 10.00 feet.
Enter a Hinge Elevation of 5.00 feet.
Enter a Backslope of 45 degrees.
Define the Material Swell/Shrinkage Factor (fraction expressed as a decimal) at .10.
- You can select either a “neat-line” total volume or include swell/shrinkage
Select the “Total excavated volume (including swell/shrinkage)” checkbox.
Click Save Configuration to Library and save the Trench calculator as Trench Example with your initials.
Click OK.

Trench Calculator – Pipe Tab

You can also use the Trench Calculator to take off how much piping and bedding you need for the trench.

Step by Step — Trench Calculator – Pipe

On the CBS Register, adjust the Forecast T/O Quantity for the Install Pipe cost item to 1000 LF.
- Assume this quantity is based off manual take-off calculations you already did
Open the Install Pipe Cost Item Record.
Add the Resource Assembly of CPIPE - Pipe Crew and adjust the production to 300 LF / Day.
On the Cost Item Record’s Actions tab, select Trench Calculator.
Select Load Configuration from Library.
Select Trench Example (with your initials).
Click OK.
On the Trench Calculator, select the Pipe tab.
Enter the following for the size and position of the pipe:
- Pipe exterior diameter: 26.00 inches
- Pipe center elevation (from bottom): 19.00 inches
- Waste factor: 10%
Click on the resource icon to pull up the Resource Rate Register.
Select the Installed Material tab.
Select MPP24 Pipe 24” PVC SDR35, then click OK.
- The Pipe variables you entered should match the following image:
Click Save Configuration to Library and save the Trench calculator as Trench Example with your initials.
When prompted to overwrite the existing saved file, click Yes.
Click OK to close the Trench Calculator.

Trench Calculator – Beddings Tab

The following steps walk you using the Trench Calculator to calculate bedding take-offs.

Step by Step — Trench Calculator – Beddings

Back on the CBS Register, adjust the Forecast T/O Quantity for Backfill Trench to 2300 CY, based on manual calculations.
Open the Backfill Trench Cost Item Record.
Add the following resources:
- LL2 Laborer – 3
- LO2 Operator Class 2 – 1
- RPC Plate Compactor – 1
- EL950 Loader 950 – 1
Adjust the Production to 160 CY/Day.
From the Cost Item Record’s Actions tab, select Trench Calculator.
Select Load Configuration from Library
Select Trench Example (with your initials), then click OK.
On the Trench Calculator, select the Beddings tab.
On the Beddings tab, you can define up to four beddings to backfill the trench
- The variables you enter will determine how much bedding you need

Enter the following variables for each bedding:

	Bedding Lift 1	Bedding Lift 2	Bedding Lift 3
Elevation (from trench floor)	6.00	38.00	76.00
Additional material needed	5.00	5.00	5.00
Conversion factor	1.60	1.70	1.60

Under Results, you can match each of the Bedding Lifts with a material resource, by selecting the resource icon and selecting the resource you want to employ from the Material tab

Selecting the resource from the Tons selection field, select the following materials for each bedding: