Working Design Files
Updated November 30, 2017
This article applies to:
- RoadEng Civil
- RoadEng Forestry
In this section, we will calculate quantities between the designed and constructed sub-grade surfaces.
We start by opening an existing road design file.
Start the Location module.
File | Open <RoadEngCivil>\As-Built\PartD.dsnx .
This design contains the desired shape of the sub-grade as well as the layers above sub-grade.
Adding a surveyed layer
The actual, as-built, sub-grade was surveyed, imported into the Terrain module and made into a TIN surface; the result is FG.terx. We will now define the as-built surface as reference surface.
Setup | Location Setup button to open the Location Setup dialogue box.
Select the Alignment tab and press the Terrains… button to open the Reference Terrains dialogue box (Figure 25‑26).
Figure 1: Adding the Surveyed Final Grade Surface as A Reference Terrain
Now we will create a reference terrain that contains a surface to be displayed in the cross section (and used to calculate volumes!).
Scroll down in the surface list and select Reference terrain 1.
Click the Browse… button and Open terrain file FG.terx.
Type “Final Grade” in Description, if desired.
Check Include in cross section.
Choose the SSG Layer – surveyed sub-grade.
Press OK twice to return to the main screen.
Your screen should look similar to the Figure 25‑27.
Figure 2: Design after Reference Terrain Surface (Heavy Dashed Line) Added
The heavy dashed line is the surveyed sub-grade (green on your monitor); it is behaving like another template component added after the designed template has been calculated. The cut volumes for layer SSG, shown in the Data window (Figure 25‑28), are mostly due to the surveyed layer cutting off the designed layers above sub-grade.
Right click in the Section window and turn on Hatch all cut areas. Zoom in to see the surveyed sub-grade cut (cross hatch – Error! Reference source not found.).
Figure 3: Cross Section with all Cut Areas Hatched
Note: Adding a Terrain surface to your sections (using a reference terrain) changes the volume calculations and the final merged surface.
Right click in the Section window and turn off Hatch all cut areas off again.
Removing Layers Using Fixed Sections
To see the difference between the surveyed sub-grade and the designed sub-grade we need to remove un-needed layers. The easiest way to do this is to create fixed cross sections. This will also allow us fix any bad cross sections by tying off layers (see exercises above).
In the Fixed Section Panel on the right side of the screen:
Click on the Add Section… button.
Select Station Range. Enter L-line Station range from 13820 to 13880.
Under Point Types turn off All. Press the button to open the Point Type Selection dialogue box as shown in figure 28-33 (on right). Select Auto interval points (20.0m). Press OK.
In the Add Fixed Cross Section dialogue box, under New Section Properties check box Start of Range (this is explained in the Volumes section above).
Figure 4: Fixed Section Panel
Your screen should see your new fixed sections in the Section Editor as shown in the Figure 25‑30.
Figure 5: Design File with Final As-Built Surface
We will now turn off the display and volume calculation for some of the unused surfaces. In the Fixed Section Panel on the right side of the screen, click on the Layer Properties… button (Figure 25‑30) to open the Fixed Section Layer Properties dialogue box (Figure 25‑31).
Figure 6: Fixed Section Layer Properties Dialogue
Turn off the Display and Volumes properties for all layers except Topo, SG and SSG. Press OK to accept and close.
The three layers between SG and SSG are the ones we really needed to disable. We could also have removed these layers to achieve the same effect (Remove button).
Now we are ready to examine the differences between designed and as-built sub-grade surfaces. The figure below shows Location set up to display a few of the key points of interest. For brevity, we will not go through explicit step by step examples for this section; these features are covered in other exercises.
Figure 7: Design vs. As-Built Quantities
By looking at the Section display, you can easily see where the surveyed sub-grade (SSG) is below the designed sub-grade (SG). The hover tips display cross sectional areas.
Hover over SSG. Right click to turn on hatching.
The Data window has been set up to show the volumes between the designed and surveyed sub-grade; this is a quantitative measure of over-build and under-build.
The bottom part of the Section Editor panel shows coordinates and slopes for points and segments in the layer polylines. If you click in the Section window to select the outer edge of the designed roadway (Figure 25‑33) you can see in the cross section editor that the designed sub-grade slopes are 33.3% and 2.0% respectively.
Figure 8: Design vs. As-Built Quantities
There are too many small segments to get a reasonable measure of the surveyed slopes using this method. However, the Measure tool shows that the surveyed sub-grade at station 13+820 (the dashed green line) has actual grades of about 47% and 1.6% (varies) respectively. To use Measure tool: right click… in section window | select Measure Tool in dialogue box | click on feature you would like to measure.
What other discrepancies can you find?
File| Close. Do not save changes.