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Purpose

To "project" an existing carriageway cross fall/gradient as represented by two 3D Polylines (for the centre and channel) onto a 2D Polyline representing a widening channel alignment.

Operation

Starting with an existing carriageway represented as 3D Polylines shown in blue. The existing centre is "a" and left channel is "c". The requirement is to design vertically the proposed channel "b" shown in red. The existing cross fall is projected through to "b". The proposed channel alignment can be within existing channels "a" and "c". In this example chainages are increasing from left to right.

Pick a reference Polyline – in this example it is "a" but it could be a different 2D Polyline. Offsets "project" at right angles to this Polyline.

Pick the 2D Polyline to be designed in 3D. In this case it is "b".

Select two 3D Polylines that will define the cross fall/gradient. These are "a" and "c".

 

Outputs are similar to preceding String functions but ensure that the correct source of chainage is set (it is the reference Polyline "a" for the above example.

Enter the name for the output section file.

Draw the section and modify/smooth as required and treat the modified design as a vertical alignment.

 

The .kdr design report file looks like this :-

 Chainage            E               N         Level     Offset  Level diff.

 

   66.507        2132.088        2240.228     93.620      6.081     -0.177

   70.000        2134.721        2237.774     93.583      6.319     -0.184

   80.000        2144.633        2232.681     93.354     10.378     -0.299

   81.006        2145.792        2232.276     93.323     11.005     -0.317