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    By Luke Howells

    Manual Turning Head Creation

    How to create a Manual Turning Head in Civil 3D

    This technique is designed to work with a ‘T’ shaped turning head. The method can be used and adapted to fit an Amorphous Turning Head. The method is similar to that of the manual junction creation.

    The Turning Head will be constructed using 4 Horizontal Alignments:-

    • The Estate Road, leading up to the Turning Head
    • The Turning Head centre line
    • The Turning Head perimeter
    • The Bellmouth between The Estate Road and Turning Head

    The Turning Head corridor will require 3 Assembly’s and an additional Temporary Road Assembly.

     

    Creating the Turning Head

    • Create the Estate Road and Turning Head centre line alignments
      • Offset either side by the desired carriageway width
      • Fillet between the Offset Estate Road and Offset Turning Head Lines and trim between
      • Close the Turning head with 2 polylines either end and join the perimeter lines together
      • Offset the Turning Head centre line once more toward the Estate Road, trim down to define the Bellmouth
      • Create Horizontal Alignments from the Perimeter Line and Bellmouth lines
        • When creating the Perimeter Line from Object UNTICK add curves between straights.
    • Create the Surface Profile and Vertical Design for the Turning Head centre line
      • Use the Temporary Road Assembly to Make a TEMPORARY Corridor and Corridor Surface
      • Reduce all Frequencies of the Corridor to 1m
    • Create the Estate Road Surface Profile
      • Add the Turning Head Centre Line TEMPORARY Surface as well as the Existing Ground
      • Create Vertical Design for the Estate Road, tying into the TEMPORARY Surface
      • Use the Temporary Road Assembly to Make a TEMPORARY Corridor and Corridor Surface
      • Reduce all Frequencies of the Corridor to 1m
    • Create the Bellmouth Surface Profile from the Turning Head Centre Line TEMPORARY Surface

    • Turn off the Surface Display for Both TEMPORARY Surfaces
    • Place both Temporary Corridors on C-CORRIDOR-FROZEN Layer
    • Create the Surface Profile for the Turning Head Perimeter
      • Add in both TEMPORARY Surfaces
      • For the Vertical Design
        • Trace the TEMPORARY Surface between the Radius’ shown on the Horizontal Geometry
        • Tie in each Radius’ with the reaming TEMPORARY Surface
      • Create the Turning Head Corridor
      • Set the Turning Head Centre Line as the Baseline
      • Assign the Carriageway Only Assembly
      • Add another Baseline
        • Turning Head Perimeter
        • Add 3 regions
          • Entering Radius, apply Fillet Assembly
          • Straights, apply Kerb and Footpath Assembly
          • Exiting Radius, apply Fillet Assembly
        • Set Targets for Radius’
          • Width Target, Right, Target Bellmouth and Estate Road
          • Vertical Target, Right, Target Bellmouth Vertical Profile and Estate Road Vertical Design
        • Set all Frequencies to 1m and Target all Earthworks to the Existing Ground
        • Rebuild the Corridor

    • The corridor is nearly complete but there are some gaps where the software cannot determine what to target. To complete the corridor, we need to add in some additional sections.
      • Draw 2 Polylines from the Intersection of the Estate Road Centre Line and Bellmouth to the Perpendicular of each Radius

    • Add in sections along the Turning Head Perimeter where Polylines intersect
    • Add in additional sections where the Radius’ meet the Bellmouth
    • Erase-Temporary Polylines

    The Turning Head is now complete. Create a Corridor Surface and merge together with the Estate Road Corridor Surface to enable the Finished Ground Analysis.

     

    For further information on this article please contact your Account Manager or call our Sales Team on 01784 419922 or email sales@cadline.co.uk