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Roadway Designer Constraints

Using the T-2-12-4-4 Template's Constraints

Found under Tools>Parametric Constraints

Parametric Constraints Panel 

Parametric Constraints or PC's have been defined for almost every conceivable aspect or feature on the T-2-12-4-4 Template.  Material depths, travel way and shoulder widths, slopes for cut and fills as well as guardrail and driveway displays.

View of Templates with Guardrail    View of Template with Fill Drive

PC's for guardrail and driveways take advantage of display rules and null points that  act as switches to turn on or off the display of these features.  To turn on LT_GR simply change the offsets to negative for the station limits you want. For Right Guardrail or drives change the start and end values to positive.  The start and end points for drives can be selected from your MX display by holding the <Ctrl> key while selecting the button.  Drive slopes can be controlled with the Drv_slope_cut or fill PC. 

The PC for LT and RT_gr_offset can be used to taper the rail offset and the LT and RT_EH_width can be used to create the widened shoulder break and guardrail platform.  See Standards GR-3 and 4 for platform grading layout or use the guardrail design excel sheet  platform tab for stations and widths.  Guardrail style has been defined as XC- Barrier and can be shut off in plan view as the Surface Feature Style Shoulders (Other - 9) style will be drawn with the 3D guardrail linestyle.

Excel Guardrrail Calcs.xls

For Guardrail using the excel sheet, copy the Yellow section and paste into a blank txt file.  This txt file can then be imported as parametric constraints.  This will work only if you are using the T-2-12-4-4 template with the above defined constraint labels.

For ditches with a separate backslope the LT or RT_ditch_bkwidth can be used, the default value is 0.

The LT and RT_EL_width is also defaulted to 0 but can be changed as above to create a turn lane or splitter island.

Related Pages


Bentley Seminars





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