Using the Tapers MVBA
The .x21 and .x30 criteria have the ability to "taper" or change values from one to another over a station range for the following elements in a proposed cross section run:
- Flat Bottom Ditch
- Ditch Foreslope
- Cut/Fill Slopes
Two ASCII text files are provided for directing the criteria what these values are and where they are to take place. A text file is available for each side of centerline. The names of the ASCII text files are shown below:
An example of the tapersrt.txt as it comes from the Typical Section Generator, is shown below (highlighted in yellow) as it looks in UltraEdit:
It is possible to edit this file manually, save it and have the cross sections reflect the values, very difficult though.
A much easier way to edit this file is to use an MVBA application that is available through Design and Computation Manager. The location for this application is shown below:
To launch this XS Tapers application, simply double click on the item, (shown above highlighted in yellow). The result is shown below, (including descriptions for the dialog icons for clarification):
Click on the Open icon and select the appropriate tapers.txt file, the Cross Section Taper Table dialog adjusts as shown below::
The values entered into the tapers.txt file will over ride the values set by the redefinable variables in the proposed cross section run.
NOTE: One exception to this is Daylight slopes. If the cross section can Daylight, the taper cut slope is ignored.
The example below illustrates what a typical set of entries might look like in the Cross Section Taper Table dialog. Once all the entries are added, it is highly recommended that the tapers.txt file be saved under another name, to prevent over-riding if a new Typical Section is applied. In the example below, I've saved my entries as "my_tapersrt.txt" and also changed the name in the Definable Variables section of the Proposed Cross Section run:
NOTE: Stations MUST be in order. Station ranges out of order will be ignored. The easiest way to correct this, is to open the tapers.txt file in a text editor such as UltraEdit and cut and paste the lines. Save the file, when you open it again in the Cross Section Taper Table dialog, the stations will be in order.
Occasionally, if a taper is desired and the exact station is keyed in to the dialog, it may be skipped when the cross sections are drawn. This is a tolerance issue. If this is encountered, you may simply start and/or end the station range for the taper "just before" or "just after" the desired station. For example, in the example below I'm asking for the fill slope to begin tapering at 50+680 with a 1:1 slope.
If after processing the run, I find that 50+680 does not have a 1:1 fill slope, I simply need to modify the station from 50+680 to 50+679.99 and reprocess the run.
Note that if a particular element is not to taper then zeros are used as place holders. When using the zeros you must however keep with the format of using the colon and showing both the rise and run i.e. "0:0". The file format MUST not be deviated from. The "+" sign for the station is REQUIRED. The ":" colons between the rise and run are REQUIRED. There are NO BLANK SPACES allowed in this file. All fields MUST be present. If a value does not change then just set the value to zeros as shown above. Lastly, note that the baseline name, station, and region are ALWAYS required.
NOTE: Tapering can never occur from some value greater than zero to zero. For example, if you wanted to taper a flat bottom ditch from 2 meters wide to a V ditch with a flat bottom width value of zero (as shown below), the tapering will not work. Remember zeros are used for place holders.
The example below illustrates correct syntax for tapering from a 2 meter wide flat bottom ditch to a V ditch: