This command creates design slopes from a perimeter
polyline at specified cut/fill slopes to reach existing ground.
This routine can be used to design building pads, pits,
roads, ditches, stockpiles, etc. The design is drawn as 3D
polylines for the cut/fill slopes and for the daylight perimeter where
the design meets existing ground. Before beginning this
routine, you must have drawn the polyline perimeter. The
polyline perimeter can be either a 2D or 3D closed or open
polyline. For a 2D polyline, the program will prompt for an
elevation for the pad perimeter. With a 3D polyline, the pad
perimeter is set to the elevations of the 3D polyline. For
an open polyline, the program will prompt for the side for the design.
With a closed polyline,
the program designs the slopes either outward or inward depending on
the setting in the dialog.
Under Source of Slope Target Surface Model, choose between a Surface File (.GRD, .FLT, .TIN), Screen Entities, or a specific Elevation. If using Screen Entities, the limits of the grid to be created are specified by screen picks. Make sure that the grid area covers the entire area for the pad including room for the cut/fill slopes.
For closed pad perimeters, there is a Slope Direction from Closed Plines option to draw the slopes inward or outward from the perimeter. The outward method starts the slopes at the design elevation of the perimeter and projects out to intersect the existing surface. The inward method projects the slopes inside to reach the grid surface or a set elevation.
Under Design Slope Format, choose between Ratio, Percent, or Template. The use of a Template allows for the complex slopes to be applied, and is also an alternative approach to road design. The template (.TPL) file is created in the Design Template routine in the Section Profile module. When using a template, the pad perimeter represents the centerline. One way to create the pad perimeter for the template is to use the Profile to 3D Polyline command which converts a 2D centerline to a 3D polyline using a design profile. With a template, the program uses not only the cut and fill slopes from the template file but also draws all the template grade points such as edge of road, curb and ditch. The subgrade, superelevation and template transition options of the template file are not used in this command. These options are only applied in the Process Road Design command. The grade points are drawn as 3D polylines parallel with the centerline. Cross section 3D polylines that include the grade points are also drawn at the specified interval.
Use Another Surface for Pad Interior will bring up a prompt for another Surface file (.GRD, .FLT, .TIN) to use for the design surface within the starting pad perimeter. Otherwise the program will model the pad interior by straight interpolation from the starting pad perimeter elevations. For example, if a building pad has a starting pad perimeter at a set elevation and the pad is supposed to be flat, then this option is not needed. This option is needed in a case where you are designing a pit and the starting pad perimeter is a 3D polyline that follows an undulating pit bottom surface. The pad design will model the pit side slopes. In order to model the undulating bottom of the pit, you need the Use Another Surface for Pad Interior option to select a surface that models the pit bottom.
Use Different Slopes for Separate Sides allows you to
specify different slopes for different
sides of your pad polyline. If this is toggled ON, the Assign Pad
Cut/Fill Slopes dialog is invoked, where you can create multiple Slope
Groups along the Pad Template polyline and set the Cut and Fill design
ratios for each.
Use Slope Pad Design allows you to set a cross slope amount for the top of the pad. You will be prompted to screen pick two points that designate the slope direction. For automatic balancing of cut/fill quantities, you will be prompted to find the optimal slope and slope direction.
Draw Slope Direction Arrows draws an arrow on the outslopes that points in the downhill direction. Arrows on fill slopes are drawn as solid filled.
Solid Cut Arrows allows you to choose between drawing the cut arrows as solid filled or as wire frame.
Round Exterior Corners holds the outslopes
around the corners. Otherwise the
side outslopes stay straight until they meet at the corners as shown in
the figure.
Erase Previous Pad Entities
erases drawing geometry created with this command previously.
When Draw Side Slope Polylines is ON, Design Pad
Template will draw 3D
polylines perpendicular to the pad perimeter from the pad to the catch
point.
Color Side Polylines assigns
different colors to Cut and Fill Side Polylines to make them easier to
distinguish.
Example of pit design for option of Use Another Grid for Pad Interior |
Pad corner without round corners option |
Pad corner with round corners option |
Side Polyline Spacing specifies the interval at which to draw the Side Slope Polylines. Besides at the interval, side slope polylines are also drawn at grid corners.
Cut volume is multiplied by the Cut Swell Factor in the final volume report.
Fill volume is multiplied by the Fill Shrink Factor in the final volume report.
You must specify the Pad Layer Name that the pad 3D polylines will be drawn on.
There is an option to calculate volumes for the pad design. The volumes are calculated by comparing the existing surface with the pad design. The inclusion perimeter for the volume calculation is the daylight perimeter polyline which represents the limits of disturbed area. The existing surface model is defined by the existing surface file (.GRD, .FLT, .TIN) or screen entities selected at the beginning of the command. The pad design surface is calculated by making a surface from the pad 3D polylines including the starting pad perimeter, the side polylines and the daylight perimeter.
Besides calculating the volumes in the Design Pad Template routine,
you can also calculate the volumes with the Two Surface Volumes
command, or the Volumes by Triangulation command. Two Surface
Volumes works with two grid files, Volumes by Triangulation works with
two TIN files. The design surface for Two Surface Volumes can be
the final output surface from Design Pad or you can create a design
surface with Make 3D Grid File using the 3D polylines created in Design
Pad. You could also create a TIN surface of the design surface using
Triangulate and Contour. Some of the reasons to use either the
Two Surface Volumes command or the Volumes by Triangulation command are
that these volume routines have more output options (cut/fill color
maps, etc.) and you can check the volumes by plotting or contouring the
surface files. Also, you can combine several pads and other final
surfaces by running Make 3D Grid File or Triangulate and Contour and
then use these volume commands to calculate the overall site volumes.
The design is drawn as 3D polylines and the earthwork volumes are calculated. Before ending, the program allows you to adjust the design by changing the pad elevation, slopes and offset. The program can find the cut/fill balance by automatically adjusting the pad elevation. If adjustments are specified, the pad polylines are redrawn and the volumes recalculated. At the end, there is an option to trim existing contours inside the disturbed limits of the pad. Then there is an option to draw contours on the pad. If contouring is selected, a dialog lets you set the contouring options. Usually you should specify a new contour layer and turn off smoothing.
A few Key things to note:
1) If the Source of Slope Target Surface Model is set to a Surface
File, and the surface file used is a grid file, then the surface
produced from the designed pad will be a grid surface and a grid file
(.GRD).
2) If the Source of Slope Target Surface Model is set to a Surface
File,
and the surface file used is a TIN file, then the surface produced
from the designed pad will be a triangualted surface and a TIN file
(.TIN).
3) If the Surface used as a Target Surface is listed in the Surface
Manager, the prompt seen in the Design Pad Template command is whether
or not to Update the Surface, which is the Target Surface, so if you
say "Yes", your Existing Ground Surface will now essentially contain
the designed pad. So if you want to maintain an unedited version
of Existing Ground, you may want to start with a copy of the Exisitng
Ground Surface.
4) If the Surface used as a Target Surface is not listed in the Surface
Manager, the prompt seen in the Design Pad Template command is whether
or not to create a new surface of the combined surfaces.
5) If you respond "Yes" to the prompt about whether to contour the
designed pad, the contouring dialog box has an option of whether to
write the designed pad as a new surface, which will be only the area
within the limits of the new design, not the entire Target Surface and
design pad surface combined.
First you are presented with the Design Pad Template dialog box.
If the Source of Slope Target Surface Model is set to a Surface
File, you will first be asked to:
Pick the top of pad polyline: select perimeter polyline
Then the Select Slope Target
Surface dialog box is presented. Choose the Slope Target Surface
file, pick Open. You then proceed to enter the slope parameters
of the pad...
If the Source of Slope Target Surface Model is set to a Screen Entities, you will first be asked to:
Pick Lower Left limit of pad disturbed area: pick lower
left These prompts appear for the
Screen Entities surface model method.
Pick Upper Right limit of pad disturbed area: pick upper
right Be sure to pick these limits well beyond the area of the top
of pad
polyline in order to make
room for the outslopes.
Make Grid File Dialog After selecting the limits of the
disturbed area the program will
generate a 3D grid that
represents the surface. Specify the grid resolution desired and select
OK.
Then,
Pick the top of pad polyline: select perimeter polyline
Then proceed to enter the slope
parameters of the pad...
Enter the fill outslope ratio <2.0>:
2.5
Enter the cut outslope ratio <2.0>:
2.5 After entering outslopes slope ratios, a range of
elevations along
the pad top will be noted.
Enter the pad elevation <29.54>:
39
Calculate earthwork volumes (<Yes>/No)?
press Enter
Report Viewer Reports cut/fill volume.
Adjust parameters and redesign pond (Yes/<No>)? press
Enter
Write final surface to grid file (Yes/<No>)?
press Enter This option will output a grid file
using the elevations of the pad within the disturbed area polyline and
using the original ground
surface everywhere else.
Trim existing contours inside pad perimeter (Yes/<No>)?
press Enter
Contour the pad (<Yes>/No)? press Enter
Existing contours with top of pad perimeter polyline |
Pad template with contours |
3D view of pad with DTM of surface and triangulation faces of pad |
Template to apply in Design Pad Template |
Existing surface with 3D polyline centerline |
Result of Design Pad Template
showing template
grade polylines, cross section polylines, cut/fill slopes, and final contours |
Viewpoint 3D view of Design Pad Template |
Design Pad Template can also handle self-intersecting side slopes |
Viewpoint 3D view of intersecting side slopes |
Pulldown Menu Location: Grading
Keyboard Command: pad
Prerequisite: A pad perimeter polyline and surface entities
or a surface file for a Target grid (.GRD) file
File Names: \lsp\flatpond.lsp, \lsp\pond.arx