Gamemaster Law on page 88 states, and I quote, "Note that an Illusionist can actually creaate an object by using a 6th level spell (combining all 5 senses). Of course, the object is temporary (only 1 minute per level) and is subject to detection by dispelling it's Feel Mirage; but it is, for all intents and purposes, a real object"
It also states that an illusion can support 5lbs of weight and for every 1lb more than that gives a 1% chance of dispelling the feel mirage. This is checked once every round.
Therefore you can create a sword or shield and it will survive one blow per 'touch' but a bridge would only survive a few steps.