SketchUp Free Version
https://www.sketchup.com/download
Step 1 - Choose a Product:
SELECT Educational use
Step 2 - Please complete the required info and select the
FREE version SketchUp Make
Step 3 - Explore and have fun, don't forget me when your rich and famous.
West Point Bridge Builder
https://www.cesdb.com/west-point-bridge-designer.html