Truly sad to see the loss of the bridge. I'm fortunate to be able to travel through a covered bridge on my daily commute, but then again there are about 10 of them used by local traffic within half an hour of my home near Lancaster, PA (remember Harrison Ford's movie "Witness" or the Turkey Hill brand of iced tea and ice cream).
Maintenance? The local governments know what treasures we have and often employ skilled craftsmen from the Amish and Plain Mennonite community.
Quality design? Seriously? This bridge FAILED in a flood. 500 year flood plains are well known and mapped and were apparently ignored by the designer or the commissioner of the project to save money or time. Saving money is what building on flood plains is all about.
Your comment about CAD is very laughable...how on earth did they build the Golden Gate, and Brooklyn, bridges without all those lazy-brain tools you've listed?
Although the design was good, proper maintenance was apparent as well. The 2nd photo shows what appear to be galvanized bolts holding the vertical members to the arch (1855 would have used wooden pegs), and the roof panels appear to be modern, possibly powder-coated versions of the old iron/copper panels.
Now if we could only get communities to provide proactive maintenance on the roadways and bridges they use every day, instead of crying to the federal government each time a pot hole opens up..... after all, it is the local community that benefits from those structures, and local profits should go to their upkeep.
Very sad, but a testament to quality design, construction, and maintenance. I wonder how they did this without CAD, computers, calculators,etc--maybe they allowed for more design marging than we would these days? And maybe they thought in terms of longer "product" cycles than we do?