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DifficultyadvancedAdded2027.0Statusdraft

Volume Calculations and Quantities

Trenches According to SABS 1200 and Quantities​

The Pipe Manager calculates quantities according to SABS 1200 automatically. Go to BOM tab, specify the Excavation Parameters and click on Calculate:

The Pipe and Structure Quantities window, where the trench quantities can be calculated:

The following properties can be set:

EXCAVATION DEPTH INCREMENT

The vertical increment allows users to calculate quantities for different depths, e.g. if a 0.5m increment is used, the software calculates quantities for each 0.5m interval, this means:

0-0.5m

0.5-1.0m

1.0-1.5m

1.5-2.0m etc.

CALCULATE

Each time any of the parameters are changed, the values in the table turns red meaning that the values need to be recalculated using the updated values.

SIDE CLEARANCE

The side clearance can be set for each min and max diameter. Min and max diameter values can also be adjusted.

REFERENCE SURFACE

As a reference surface is used Design Surface:

BEDDING CLASS

The bedding class is according to the SABS 1200 LB. Each pipe can use a different bedding class. To set the same value for selected pipes or for all pipes, right-click on the column heading and use the Bedding Class command:

Quantities can be exported to Excel file with the Export BOM command.

Each subtab is exported as individual sheet, see the exported BOM opened in Excel:

Non-Standard Trenches​

Note: This topic assumes that the reader is familiar with the subchapters Assembly, Corridors, Create Sample Lines, Create Multiple Section Views, Corridor Quantities (applicable for roads)s) from the CIVIL 3D ESSENTIALS chapter.

  1. If you need a trench with sloped sides, create a trench corridor. For the horizontal alignment use a pipe alignment, for the vertical profile use a profile from the surface and for the assembly use TrenchPipe1, TrenchPipe2 or TrenchPipe3. These subassemblies allow users to specify the pipe network(s) which they follow. You can also specify the bedding depth, backfill depth and cover, side slope and pipe network offset.

Subassembly settings:

Assembly with TrenchPipe subassembly:

  1. If you need a more complex assembly, use a combination of the TrenchPipe assembly, generic links, subassembly from polyline, conditional subassembly, pavement stripping (for soil stripping) etc.

An example of a more complex trench assembly:

An example of a trench assembly with conditional subassemblies:

Corridor settings:

  1. Set targets for the corridor in the Target Mapping window:

Trench corridor:

  1. To calculate volumes, create sample lines with the Sample Lines command in the Home tab:

  2. Go to the Sample Line Group properties, Material List tab and specify the materials. Use Structures (Assembly shape) for the Quantity Type of the Bedding. There is a shape for the Backfill but it does not exclude the pipe, so the volumes are incorrect. The best way to calculate other quantities is to create surfaces and calculate the volumes between the surfaces.

Material definition:

  1. Two options are available to calculate the backfill volume correctly. The first option is to get the quantity of the backfill from the assembly shape, then manually subtract the pipe quantity. The disadvantage of this procedure is that you won't have a dynamic quantity table in the drawing. The second option is to create a new assembly with the pipe area transformed to a rectangle. This is useful for volume calculations between surfaces. To create this assembly, use generic links (LinkVertical, LinkWidthAndSlope, LinkSlopeToSurface). The width of the rectangle is the same as the outer pipe diameter and the height must be calculated from the area you need to transform. For a general formula of the rectangle's height, multiply the pipe diameter by 0.785. Assemblies must be created for all pipe diameters used in the project.

  2. Create a new corridor with this assembly. For the alignment use the pipe alignment, for the profile use the profile from the Backfill surface (create this surface from the trench corridor), for the assembly use the assembly created in the previous step. For the target surface use the datum surface created from the trench corridor. You can create more regions for different pipe diameters.

The corridor in a 3D view:

Created surfaces from the corridor:

Created surface for the Datum and Bedding, see the settings in the image below:

  1. Create a new material in the Sample Line Group Properties and specify the surfaces between which the backfill material must be calculated.

The calculated material displayed in the cross-sections:

  1. To insert a material table into drawing, go to Analyse ‒ Material Volume Table. In the opened window specify the material you would like to create a table for.