In AH1 there was an Aussie, his name slips my mind, but he had a map with destructable bridges. In fact it was quite fun to sit in the middle of the bridge while the bridge blew up and you fell several hundred feet in a tank. Perhaps the bridges could be set like hangers, re upping after 15 minutes if they were just for GVs not supply convoys. Otherwise leave them down for an hour or so unless resupplied.