At various points (e.g. 00:14) in this BBC documentary on Mostar's Stari Most (Old Bridge) you can see dozens of car tyres hanging from the bridge prior to its destruction in the Croat-Bosniak conflict.
Histories of Mostar's role in that conflict mention the tyres (and mattresses) which were employed "in vain" by its defenders to protect its weakest points from the shelling. It seems the bridge withstood several hits by artillery so perhaps the tyres did help a little.
Were the tyres some use in protecting the structure from shelling?