I just recently had a chance at some free 2 x 8 x 3/16 rectangle. I've got 4@13' and 5@8'. I've always wanted to build a heavy duty dump trailer one day. Would this material be adequate for say a 12,000 lb trailer frame at 10' long?

I plan on buying plans online and having a real welder friend come over and weld it for me once I have most of the material together. Any help would or opinions would be appreciated.

This is is my first post although I've been lurking for a year or so.