Calculate Minimum Vertical Distance

The tool calculates the minimum free vertical distance (maximum vehicle height) between a road surface and a crossing bridge superstructure.

Before this function can be used you must create a plan drawing of both the road and the crossing bridge (Define/Draw Horizontal Geometry). This function works on 3D polylines and 2D polylines in the drawing, but normally you will use 3D polylines when you work with bridges. You must therefore remember to select the 3D option in the plan-drawing dialog for both road and bridge (default is 2D). Also, remember to de-select the Curve-fit option.

When the plan drawings are prepared, run the tool, Calculate Minimum Vertical Distance, which can be accessed from the following locations.

Find the function here:

Ribbon: Bridge > Tools Calculate Minimum Vertical Distance

Command prompts for:

• Pick road surface polyline(s): Select objects - Select any number of road surface lines. Finish with the key 'Return' or 'Right button of the mouse'.

• Pick bridge surface polyline(s): Select objects - Select any number of bridge surface lines. Finish with the key 'Return' or 'Right button of the mouse'.

Tip: Use AutoCAD's selection options crossing window.

The program will then start to calculate the vertical distance at all intersection points. After the calculation is completed, the minimum distance will be displayed on the command line.

Minimum vertical distance: 4.370 m

The position of the intersection point with minimum vertical distance is marked in the drawing with a crosshair.

Press enter again if you wish to repeat this sequence.

Note: Linear interpolation is used between calculated sections (user-specified interval). If the vertical geometry of either road or bridge is not linear in the actual profile interval, this interpolation will create a small error in the calculation. You should therefore always make sure that your selected interval between calculated sections is sufficiently small.