Not sure about your bridges point - I see the bridges over the Forth most days which are from the 1880s, 1960s and the new one opening this year and they all look pretty different to me (cantilever, suspension & cable stay respectively).
Would something like the Millau Viaduct have been possible in the 1960s?
> Would something like the Millau Viaduct have been possible in the 1960s?
That's two questions in one.
The crossing of large spans was a solved problem in Roman times (pillars and arches).
To do it exactly like that did not require anything new in terms of materials, but there would have been quite a problem getting such a design approved without the computational homework done that it would work well in all weather conditions. Which in turn would likely lead to it being overdesigned.
Computers are excellent at such simulations leading to a higher degree of confidence in designs that have never been tried before or that push the envelope in some manner.
Would something like the Millau Viaduct have been possible in the 1960s?