There’s a book named “Recueil de Types de Ponts Pour Routes...”
I’m confused here that, if “types” is in plural form, shouldn’t “des” be used instead of “de”?
"Des" is also possible, but with a slightly different meaning :
One would expect these books to contain all the bridges matching the title. I interpret des in this case as the de+les contraction, not the partitive des.
Recueil de type de ponts is more generic. It's just a book containing types of bridges.
One cannot imagine a book simply called : Recueil des ponts, without raising the question "lesquels ?" While a book called simply Recueil de ponts seems quite plausible.
In my understanding Recueil de types de ponts is equivalent to
compilation of bridge types
while Recueil des types de pont is equivalent to
compilation of the bridge types...