The question is, just how hard is it to make a lightweight cardboard object capable of supporting a person’s weight? I know that it can be done, in theory. But sometimes you just have to see it to believe it.
The answer is, it’s not hard at all, to make a cardboard structure that will stand up to the weight of an adult. Hence, the brief piece of performance art below that I call “fat man stepping on a cardboard box”.
What you see above is an example of the “structural grid plus envelope” method for creating corrugated cardboard structures (Post #887). Except I didn’t even bother to create a grid. I just tossed in a bunch of strips, cut to height, and folded into “V”s.
If that works, as sloppy as that is, it’s going to be a piece of cake to make a set of steps capable of supporting a seated adult.
In fact, the challenge here wasn’t even in supporting the weight. The biggest challenge was getting those strips cut to a uniform width, so that the weight would be evenly distributed. But even with all the sloppiness, it’s obviously no big deal to construct something out of cardboard that will support the weight of an adult.