Extend Surfaces
Located under Cross-Sections - Settings within RoadCalc, there are now options to Extend Surfaces. In some cases, surfaces may need to be extended in situations where there is insufficient surface data to tie one or more surfaces into each other to form a closed region. These closed regions are then used by RoadCalc to determine the end area for a particular material, which is then used to obtain volume quantities.
Figure 1
With the Extend Surfaces toggled OFF, RoadCalc behaves as it has in past releases. For example: When using Run Design, RoadCalc will read the condition table for a range of stations to determine the catch slope. If the Original Surface for a given cross-section does not extend far enough for the slope that is being processed, RoadCalc would extend the slope to the limits of the Original Surface. At that point, RoadCalc will tie the Design Surface to the Original Surface vertically. This is shown in Figure 2 on the left side of the centerline.
Figure 2
If for some reason the Original Surface didn’t extend far enough to reach the Design Surface, no tie-in could be performed. Original Surfaces need to extend as far as the Design surface because surfaces within RoadCalc cannot ‘double-back’, or exist twice at the same offset. This is shown in Figure 2 on the right side of the centerline.
For one surface to tie into another, the surface data for one or more cross-sections must have undergone a change such that this surface tie was now possible. The following is a list of commands that may result in surfaces tying together:
· Manage Surfaces - Delete
· Edit Cross-Section Data
· Extract Cross-Sections
· Import Cross-Sections
· View Cross-Section Graphics
· Cross-Sections - Synchronize Graphics and Data
· Process - Run Design
· Data Transfer - Import LandXML
With the Extend Surfaces toggled ON, RoadCalc will now extend the original surface(s) when there isn't enough original surface data to tie all appropriate surfaces for one or more cross-sections. Here are some examples illustrating the Extend Surfaces Options:
Examples
If there isn't enough original surface data, RoadCalc will now attempt to extend the original surface using the method selected in the Cross-Sections Settings dialog box. For example, if you are performing a Run Design, you may choose to have the Original Surfaces extend horizontally from the outermost points or choose to extend the slope of the outermost segment. Additionally, the Design Surface may be controlled to tie into the Original Surface vertically or by extending the slope of the outermost segment to a catch point.
In the case where the Design Surface exceeded the Original Surface, RoadCalc now extends the Original Surface far enough to tie vertically with Design Surface. See Figure 3.
Figure 3
When RoadCalc extends the Original Surface, there may be additional Original Surfaces, or Subsurfaces that may also need to be extended. See Figure 4.
Figure 4
There is a toggle in the Surface Extension Options to Extend Subsurfaces, which is toggled ON by default. If this option is toggled ON, and there is a change in surface data that precipitates the extension of the uppermost Original Surface, subsurfaces that are of a Parallel surface type will extend parallel to the uppermost original surface. Subsurfaces that are of the Absolute surface type will extend horizontally, regardless of the extension method for the Original Surfaces.
If the extension method for the Original Surfaces is set to ‘Extend Slope of Outermost Segments’, RoadCalc will prevent any Absolute surface from extending through an original surface immediately above it, thereby continuing the absolute surface along a path parallel to the surface above it. See Figure 5.
Figure 5
If RoadCalc determines that the surfaces will not tie when performing a surface extension, then the design surface will attempt to tie to the original surface vertically from the outermost point. For example: You are Importing Cross-Sections for a Design Surface. RoadCalc will attempt to tie the Design Surface to the Original Surface using the extension method specified in the Surface Extension Options dialog box.
If you choose to extend the slopes of the outermost segment, there may be a situation where both the Original and Design surfaces are either diverging or the surfaces parallel each other. When this happens and the paths of the two surfaces don’t intersect, RoadCalc will vertically tie the Design Surface to the Original Surface. See Figure 6.
Figure 6
If both surfaces are converging but may converge at some distance that is unacceptable, you may specify a Maximum Distance to Extend the Original Surface. See Figure 7.
Figure 7
Another way to control the surface extension performed is using Right of Way (ROW) alignment(s) specified in your subproject. To do so, toggle the option to Use ROW Limits to extend ON in the Surface Extension Options. See Figure 8.
Figure 8
For example: You have specified ROW alignments defining the construction limits of your project. In certain areas of the subproject, there may not be enough Original Surface data to extend to the construction limits of the project if necessary, but you know where those limits exist all along the centerline. When you process your Design Surface, the surfaces that may have extended beyond the ROW will now extend up to the point where the ROW exists, then tie vertically. See Figure 9.
Figure 9
Reports
If a surface extension or surface tie-in occurs upon importing a Data Transfer LandXML file, importing cross-sections, performing Run Design, or by editing cross-sections graphically or numerically, the Surface Extensions dialog box will display. This reports the station where the extension or tie-in took place, the surface(s) that extended or tied-in, and the method used by each surface to extend or tie on either the left, right or both sides. This detailed report may be printed to the printer or sent to a file and this information is only available at the time the information is displayed. Each new series of extractions, imports, edits or Run Design may yield a different report with different results.
To display what stations and what sides have been extended or tied-in, you may toggle on the Surface Extensions option in the Generate Cross-Sections Reports dialog box. Here you can specify a station range for the report as well as send the report to the printer or a file. This report displays all instances where a surface has tied or has been extended.