Here are some tell-tales that I welded for a project. I have a more efficient design using threaded rods, nuts washers, and a much smaller outside diameter tubing used in other projects.
I made several for this project.
Tell-tales are used to measure vertical deformation in soil profiles at selected depths. As the load is applied to the section, the base plate and the interior pipe move with the soil at the base
plate elevation. The exterior pipe minimizes interference from the soil or ballast above the base plate.
This was used in the research project:
Mid-America Transportation Center
Report # MATC-KU: 36
Performance of Geogrid Reinforced Ballast under Dynamic Loading