Magic can also apparently make large objects fly, or at least float above the ground. The mage has to concentrate really hard for this to happen but it still appears to contradict what the codex says in DAO about how magic can be used. There the mage states quite clearly that if you want to get from A to B you have to walk.
May be this new use of magic, to repair bridges, will be explained in DAI. It could be restricted to the Inquisitor and something to do with their Fade ability.
I think the best way to explain apparently new lore with regard to magic is that codices and even World of Thedas is based on lore that the majority of people in Thedas know about. So it doesn't mean that something is not possible, just that most mages are not aware of it. Given the majority of mages have been confined in Circles with magical research limited to what is approved, it is hardly surprising they may not be aware of the extent of magical possibilities. By contrast in the Tevinter Imperium the mages are free to experiment as they wish and also have a long tradition of magical research. The strengthening of buildings by magic probably dates back to the time of Ancient Tevinter and they in turn may have got their ideas from the elves. After all the elves managed to create a series of magical pathways which are neither in the material world or the Fade and that have a bad affect on non elves, so really after that, anything is possible.