[MentorOfSteel]

Some photos are attached. I had the details wrong above, here is a more accurate description: There are 9 12"x12"x2" concrete paving stones attached to the underside of the bridge, for a total of about 180 pounds of extra ballast. Five of the blocks are distributed along the centerline of the bridge, the other four on in a line off to the side. They are mounted in 2"x4" framing so that they can be easily reconfigured later if necessary (e.g., if/when we cover the surface with polycarbonate).

-George