I worked on a highway job with mine hauling blasted rock. I didn't have to worry about weight and scales and this was a temporary thing. I took it in and out when needed. What I did was the 2x8's on the floor. I had the first batch cut full length (20 feet). Welded flat bar across the front by the hoist tunnel to hold them down. Used angle across the rear. Also used a router to notch the ends of the boards so as the rocks slide out, they could not catch the angle and tear it up. Soft wood worked as well as hard wood. All your wear will happen at the rear and we worked 12 hours a day, five and six days a week for about 6 months. About half way through, the rear was wore down pretty good so we cut it at the half way point of the box and just re-did the back half. Welded flat bar across the joint (again countersunk into the boards). When it was time to remove, grind some welds off and out it comes. My friends used the same method on their side walls, but I had a Beauroc (junk) Diamond Line box with curved sides, so I welded studs all along the top rail and hung conveyor belting like a curtain. Worked perfect. Ya, lots of work but a hell of a lot cheaper than a liner, and when it's out still had my light tare weight. Sorry no pics though (I don't think anyway, I'll have to check when I get a chance).
