Detailed Pavement

Detailed pavement is used to define the pavement description in more detail than the normal pavement description is capable of doing.

The function can be started from the road task under Design > Detailed Pavement.

The left pane folders and the surfaces are having shortcut menus.

Use this function for a detailed description of the road pavement layers.

• Roadbed will be described by surfaces extending from the centerline.

• For each cross-section with detailed pavement description, the roadbed layer must be defined on each side of the alignment with a 

  • Surface

  • End Surface

• The pavement thickness is based on the thickness set in the dialog for Pavement.

• Describing roadbed surfaces has a lot in common with road surface descriptions.

• Pavement surface edges can be linked/follow road surfaces.

• Pavement surface edges can be linked/follow alignment objects.

• The roadbed can be shaped differently on the right and the left side of the centerline.

• A maximum of 15 pavement surfaces can be described on either side of the centerline for each pavement layer.

• The roadbed surfaces are described longitudinally with reference to chainage and the cross-section by width and slope.

• Each row in the dialog will represent an interpolation point where the width and/or slope of the surfaces are changed.

  • Between two break points (a section), linear interpolation will be carried out for width and slope.

  • This is in addition to changes on the connected road surfaces or alignments.

Procedure

The shape of the roadbed is designed by defining the roadbed surfaces in cross-sections.

• Roadbeds can consist of a maximum of 15 surfaces on each side of the centerline, one of them being the End Surface.

• Along the alignment, the surfaces are defined with reference to the chainage.

• The parameters, width, slope, and stationing/chainage forms the description of the surface.

• You do not need to define the depth of the roadbed as this will be done automatically based on different principles, whether the checkbox for Control of min. roadbed thickness is turned ON or OFF.

• Select a roadbed surface from the left pane of the dialog Road Bed and define the surface description. Use as many surfaces as required and end the roadbed using the End surface.

• The surface close to the alignment is Surface 1.

Chainage/Stationing

Roadbed surface description (roadbed width and slope) is referred to the stationing/chainage and between two successive stations/chainages, linear interpolation will be carried. Using chainages, section basis roadbed surface description is possible.

• A roadbed surface that has the same or an interpolative width and slopes for a section is described by entering the first and last chainage, width, and slope for the section.

• The sections must be described using ascending chainages.

• Insert - Use this button to insert a row in the right pane of the dialog box.

  • Select a row, above which a new row is to be inserted and click the button.

• Delete - Deletes the selected row from the right pane of the dialog box.

• Undo - Cancel the previous action.

  • It is also possible to press Cancel on the dialog to revert all changes since the last time OK or Apply was used in the dialog.

• Any character other than the numeric value in the cells of the column Chainage will define Break.

Shortcut Menu

• Use the option Make Copy Opposite Side of the shortcut menu of surface (left pane of dialog) to copy the description on the other side of the centerline.

• The cells of the right pane of the dialog are also having the shortcut menu with the options copy, paste, etc.

Roadbed surface - Width

Roadbed width can be defined in three methods

1. Fixed width

2. To surface edge

3. Alignment

Once a value is defined for the width, the cell of the row corresponding to other methods will turn gray.

Fixed width

• Define the horizontal width (meter) for the active roadbed surface.

• See example - Surface 3 (Left Side) below.

To surface edge

• Select a road surface from the drop-down menu of the cell corresponding to the column 'To surface edge'. The roadbed surface will be projected to the farther end point (from the centreline) of the selected road surface.

• See example - Surface 1 (Left Side) or Surface 2 (Left Side) below.

Alignment

Exiting objects (alignment stored in the digital terrain model) can also be used to define the width of the roadbed surface. The roadbed surface will be projected to the vertical plane of the selected object.

Use the button New Alignment to open the dialog Alignments as Surface Edges where the details such as section limits (start and end chainages), method, and the object to be used as the surface edge can be defined. Two sub methods are available for using the details of the object to define the width of the roadbed surface:

1. Distance from a line and slope from the surface description:

   • The roadbed surface will be projected to the selected object.

   • The slope of the roadbed surface is to be defined in the dialog Road bed.

2. Distance from a line and slope from the vertical alignment of the object selected:

   • The roadbed surface will be projected to meet the selected alignment.

Define the start and end chainages, choose a method from the pull-down menu at Method, and select the object from the list. The section limits object selected, and the method adopted will be displayed in the columns Chainage, Alignment, and Alignment method of the dialog Road bed.

• To edit the details of such sections at a later stage, click in any cell of such section and use the button Edit Alignment.

• For further details, refer to Alignments as Surface Edges.

Note: Using alignments is not applicable for End surface or in DeepBlasting.

Beam Slope

Using beam slope the designer can add additional width to the roadbed surface based on a beam to assure load carrying capacity (load dispersion) in the road pavement.

• Define a slope value to increase the horizontal width of the roadbed surface measured out from a road surface edge.

• See example - Surface 1 (Left Side) below.

Widening

Using widening, the designer can add extra width to the roadbed surface.

• Define the additional width (negative prefix will reduce the width) for the roadbed surface (generally useful when the method To surface edge or Alignment is adopted).

• See example - Surface 1 (Left Side) below.

Beam slope and widening can be used independently of each other.

Road bed slope

Roadbed slope can be defined with one of four (4) methods:

0 - Slope as a decimal value

• Select this method from the drop-down menu of the cell of column Slope method and define the slope in the cell of the Slope column. Use +/- prefix.

• See example - Surface 2 (Left Side) or Surface 3 (Left Side) below.

1 - Slope as a road surface

• Select this method from the drop-down menu of the cell of column Slope method and select the road surface, the slope value of which is to be applied for the roadbed surface.

• See example - Surface 1 (Left Side) below.

2 - Slope to pavement bottom

• Select this method from the drop-down menu of the cell of column Slope method to have the roadbed surface extend to the bottom of the pavement. It is important to have the correct slope (upwards/downwards), and to have set a length of the surface that goes just past the pavement bottom that you want to extend to.

3 - Slope as pavement bottom

• Select this method from the drop-down menu of the cell of column Slope method to lay the roadbed surface parallel to the pavement bottom as defined in the Normal Pavement description. In this case, the cell Slope will turn grey. Typically used when not needing a specified detailed description in some part of the cross-section.

Example

• 0.0 to 50.0m; 50.0 to 75.0m; 75.0 to 125.0m; 125.0 to 150.0m and 150.0 to 200.0m are the sections in the above example surface description. 0.0m is the start chainage and 200.0m is the end chainage for this roadbed description.

• From chainage 0.0 to 50.0m, the surface description (slope) has changed, and thus linear interpolation will be carried.

• From chainage 50.0 to 75.0m, the surface description is the same, and thus the roadbed surface will be uniform. Similar is the case for the section 75.0 to 125.0m and 150.0 to 200.0m.

• For chainage 75.0m, two surface descriptions are defined, and thus there will be an abrupt change in the roadbed surface at chainage 75.0m.

• Break: From chainage 125.0 to 150.0m, Break is defined (using the button Break), and thus there will not be any roadbed surface between 125.0 to 150.0m.

End Surface

Using the end surface, the designer will have full control over where the roadbed ends. The roadbed can even end outside the road surfaces.

The end surface of the roadbed can be described with one of four methods:

1 - Calculate end point

• The end point of the end surface will be calculated based on a given slope starting after the previous surface.

• A value for the slope must be set.

2 - Calculate slope

• The end point is defined in this method by selecting a road surface.

3 - Calculate start point

• The end point and the slope of the end surface are defined in this method. The system will calculate the start point of the end surface.

• In this method, the width of the preceding roadbed surface will be adjusted to fix the start point of the end surface.

4 - Slope from next surface and end point

• The end surface will end at the selected surface edge.

• The slope of the end surface will be equal to the following surface in the cross-section calculation.

• The start point of the slope will be moved to satisfy the above bullet points.

Some of the end surface methods will override the endpoint of the previous roadbed surface in the description.

Examples

Surface 1 (Left Side)

• A = Roadbed Surface 1 (Left Side)

• B = Road Surface (-2.1 L. Shoulder)

• C = To Surface Edge (Roadbed surface will be projected up to this line)

• D = Additional width considering beam slope (to ensure carrying capacity)

• E = Beam slope

• F = Widening

• G = Pavement layers

• H = Centerline

• I = Terrain

Surface 2 (Left Side)

• A = Roadbed surface 2 (left side)

• B = Road Surface (-4.1 L. Ditch)

• C = To Surface Edge (roadbed surface will be projected up to this line)

Surface 3 (Left Side)

• A = Roadbed surface 3 (left side)

• B = Roadbed width (fixed-width)

End Surface (Left Side)

• A = Roadbed End Surface (left side)

• B = Calculated end point (using the slope value) of the surface

Relations (road bed - pavement)

Relations between the roadbed and the road pavement

The lowest layer in the road pavement is laid parallel to the roadbed description. If reinforcement layer 2 is inserted, the lower edge of the next lowest layer will also be parallel to the roadbed. The overlying layers will be laid out parallel to the road surface.

If the roadbed description is given a plane that theoretically comes higher than an ordinary road pavement, it will be inclined in level to the lower edge of the lowest road pavement layer, where this is possible.

• A = Roadbed (formation) description

• B = Normal formation (Sub-base)

• C = Road surface

• D = Pavement layer (Surface)

• E = Pavement layer

• F = Centerline

If Rehabilitation of existing road in use: Roadbed description will not be carried out on parts of the profile, which are assimilated to existing road rehabilitation unless a variant of surface slope method 3 is used to follow the bottom of the road bed.

Termination of Road bed

Termination of the roadbed against bottom drain and bottom fill

The roadbed will normally be terminated where the roadbed surface cuts through standard drainage ditch or fill surfaces.

• If the roadbed surface is situated deeper than the bottom of the ditch or the foot of the embankment, Novapoint Road Design will not find the cutting point.

• On the side of the cutting, solves this by terminating the roadbed against the ditch bottom (outermost ditch surface with negative gradient).

• A surface with the same gradient as the innermost soil or rock-cutting surface is inserted from the outermost ditch surface with a negative gradient, to the cutting with the roadbed.

• Termination against an embankment foot occurs when a break is inserted into the roadbed directly below the start of the first fill surface (normally the shoulder edge).

• From here, Road Design will insert a roadbed surface up to the foot of the embankment.

• The figure below shows the termination of the roadbed against the bottom of a ditch and the foot of the embankment.

• A = Terminates against drain bottom

• B = Terminates against fill bottom

• C = Road pavement Description

• D = Pavement (Surface)

• E = Road Surface

• F = Terrain

• G = Centerline

• F = Pavement layer

Always use ditch surfaces! If several ditch surfaces have been used in the surface description of the road top surface, the roadbed will be terminated, as mentioned, against the outer edge of the outermost ditch surface with a negative gradient. Therefore, always enter ditch surfaces in the profile, even if only with a width of a millimeter.

At narrow road bed description: If the roadbed description is narrower than the roadbed, vertical termination surfaces will be laid out up to the lowest road pavement layer as illustrated below.

• A = Pavement Description

• B = End pavement description

• C = End Surface (Vertical ending)

• D = Standard lower edge Sub-base

• E = Calculated Sub-base

Next topic: Deep Blasting