Don't trolls weigh 2-3 times what a normal person does?
Count on that.
Bridges that can hold a human weight, bunch of defenders at the far end, troll rushes into combat, bridge collapses.
Oil and fry and have a break from subsequent trolls.
More later,
Vahktang
Another good one I think it Zulu for that kind of "million of them versus 100 of us." 
