(Side note: the bridge pictured in the article is the Bridge of the Gods, just upstream of Bonneville Dam on the Columbia River. There's going to be more than bridge problems if the flow of the river takes out that bridge.)
In the case of bridges, you're going to get the basic Steel or Concrete code, maybe some federal guidelines if it's an interstate, definitely state DOT standards.
As for modern vs not -- There are definitely classes of bridges that I'd not consider modern. Anything with rivets, or sections that are built up by lots of little pieces (like the old style riveted trusses). Those aren't done anymore for several reasons: onsite labor is more expensive than shop labor, rivets are inconsistent and weak compared to bolts or welds, and the ongoing painting to control corrosion is a nightmare. In places like the West Coast, the older bridges are not built to current seismic standards, which have been evolving as quickly as the rest of the codes (e.g. tiedowns, base isolation, column jacketing). A lot of the older bridges also have details that aren't terribly good for fatigue performance.
There was definitely an inflection point, probably in the 80's where precast prestressed concrete started being the go-to design for more than just a plain old girder bridge over the interstate.
"The AASHTO LRFD Bridge Design Specifications are intended for use in the design, evaluation, and rehabilitation of bridges, and are mandated by the Federal Highway Administration for use on all bridges using federal funding."
It is over 2000 pages long without errata. It is updated yearly with major updates less frequently.
That will be heavily spalled 50 years from now. Almost as dumb as building thin flexible skyscrapers with reinforced concrete.
There are thousands of slender concrete structures that have been in service (thus far) without issue.
https://commons.wikimedia.org/wiki/File:Forth_Replacement_Cr...
Three bridges built in 1890, 1964 and 2017 respectively (from right to left in the picture above).