That's definitely a really awkward choice of word in that context for it not to be intended, so I'm thinking pun was, in fact, intended. You can try to convince me otherwise but in order to do so I'll need to see some concrete evidence (pun not intended)
Anyway, I really didn't intend the pun! My reaction to the article was to try to get a rough estimate of how reliable tower cranes are, at which point I realized that they must be very reliable to work at all. But I only had that broad hypothesis of "very reliable", so I went looking for evidence to confirm it, and if so, what that broad hypothesis ended up looking like in practice. For whatever reason I found "concretely" when I went looking for a word for the segue. Probably concrete on the brain and a bit of luck.