I don't know what to do with our pitbull please help.?

Our 9month old pitbull plays very very rough, she jumps and nibs anyone, even me. I mean I feed her right, took care of her and this is what she gave us back? i tried every suggestion. I don't want to give up on her. She jumps and bite, then jump and bite over and over again, she even rips my brother's T-shirt and left some bite wounds at the side of his stomach. I usually chain her to keep her from harming any of us. If i get her loose it's like all hell breaks out. There is no sign of aggression, She just plays, and chews everything around her, from our motorcycle, to our car. She's turning to be, somewhat "dangerous"..What should i do, I really don't think hurting her is gonna work. Y_Y