Talk:Cayey Bridge

Girder type
Can we clarify what the technical details of this bridge are?

As is obvious from the photos, and from the NRHP listing, this is not a lattice girder bridge. The lower third of the girder is a solid plate girder instead. That means that it's not a lattice girder, it's a compound of lattice and plate. The lower third is plate, where the main tension forces are, so the lattice part is mostly in compression. That's odd for a lattice truss, they're not strong in compression.

So what is this thing? Is it some peculiarly Belgian design? Belgium, at this period, was quite innovative in bridge designs - especially Arthur Vierendeel, who might have been involved in this (and as a famous Belgian, deserves linking if this can be demonstrated). If compound lattice and plate girders like this are a repeated design, then they deserve specific coverage as such, either in the list of trusses article, with this bridge, or under the article for Nicaise et Delcuve themselves.

It's quite likely that this bridge, lattices being rare, is known as "the lattice girder bridge". But because the mechanics of it are so different from other lattices trusses, we should not confuse the two in a structural sense. Andy Dingley (talk) 14:59, 8 July 2016 (UTC)