A pipeline profile is an engineering drawing that displays the surface condition of the route the proposed pipeline is going to pass through in terms of the slope. It is an important document for an engineer because it helps him draft an accurate bill of quantities as well as making other decisions.
A bill of quantities for a pipeline would include the cost of pipes, excavation and pumping stations. The pipeline profile will help the engineer visualize whether the liquid to be transported will flow by gravity or will need the help of pump boosters on certain sections of the pipeline route.
The following steps give me excellent results when creating a pipeline profile. They are outlined from the fieldwork to the final output in AutoCAD Civil3D.
- Assuming you’re using RTK to pick data, pick three points across a 10 meter width cross-section as you move at intervals of 25 meters along your pipeline route. Pick any other necessary details like Road edges, Structures etc. to help you put the pipeline route into perspective.
- Once you’re done picking data in the field, export the data from your data controller in your preferred format. I prefer excel format with csv extension. Arrange the data into your preferred order. It could be PNEZD, PENZD..etc. Copy the file into your PC or laptop.
- The next step is importing data. This should be straightforward. In your Civil3D, go to the menu bar and click…Points>Import/Export Points>>Import Points. A dialog box appears where you should define the location of your csv. Also select the order in which you stored your data (PNEZD).‘Add points to group’ and give it a name. Make sure the box (Do elevation adjustments if possible) is checked and then click OK. If your data does not appear go to menu bar again, click…View>Zoom>>Extents.
- Now that you have the data, draw a poly-line through the data (preferably in the middle) and make sure it is one continuous poly-line (no joints). Once that is done you might also want to draw a boundary around the data by joining the outermost points in the data. This will help in defining the extent so that the software does not generalize the eventual surface. The boundary should be a loop closing in on the point where you started the boundary poly-line.
- The next step is to construct the surface. On the Prospector tab of the Toolspace pallet, right click on the ‘Surfaces’ icon and select ‘Create Surface’. This should bring a dialog box. Click OK. A default ‘Surface 1’ should appear under the tree of the ‘Surfaces’ icon. Click on the ‘+’ sign on ‘Surface 1’ and define the csv file to be used to construct the surface. It should be the same file you imported in Step 3. The surface should appear now as contours surrounded by a green boundary. Under the ‘Surface 1’ icon right click ‘Boundaries’ and click on ‘Add’. Type any word and then select the boundary you defined surrounding the data (The cursor changes shape to a tiny box.) The green boundary should now overlap with the boundary you created in Step 4.
- Once the surface has been created, the next step is to create an alignment that will form the basis of your profile. On the menu bar click… ‘Alignments>Create Alignment from Polyline’. After this the cursor changes shape to a tiny box. Select the polyline you created earlier passing through the middle of the data. Uncheck the box ‘Erase existing line’. This will give you a chance to create another alignment in case you make a mistake. A new green line with Chainages at defined intervals is formed that overlaps with your polyline. This ‘Chainage line’ will help you identify the level of the slope at a particular chainage against your profile. You can name the alignment if you so wish.
- The next and final step is to create the profile. On the menu bar click…Profiles>Create Profile from Surface. A dialog box appears with a drop-down box that lets you define the alignment with which the profile will be based upon. This should be straightforward since it is the alignment you created in Step 6. Then you have to select the surface which is also the one you created earlier (Surface 1). On the profile list window (still on the dialog box), select the row that appears and then OK. A subsequent dialog box appears in which case you OK all the steps. When this is done, you’ll have to choose the origin of the profile on the model window with the special cursor that appears. Voila! You have your pipeline profile!
NB: To create a pipeline profile you need an alignment and subsequently the alignment needs a surface. The three are inextricably linked; Surface, Alignment, Profile, in that order.
Hope you learned something.
