A few months back I picked up a gooseneck equipment trailer. It was made in a farm shop. Overall its pretty decent, but it has some issues. It was decked in what looks to me like bowling alley planking. I was told its the same heavy duty engineered wood as is used on some commercial trailers. Its quite strong. With a 7000 lb tractor on it there is no sagging under either axle when its fully on the trailer. Even when the ratcheting chain binders are cranked down.
However for some reason it is not supported at the very back of the trailer. Its about 2wo feet to the first cross member that supports it. I have driven the mentioned tractor up the ramps and onto the trailer over that end. I went very slowly so that I could slip from the forward pedal to the reverse pedal at the first sign/sound of cracking. There was no sound of cracking and I successfully loaded and unloaded the tractor, but the end of the boards did sag rather substantially. There is rather substantial steel at the back of the trailer. The boards just stop short of it. The bottom is also slightly below the level of the outer frame.
I have consider a couple options. One is to weld in a support cross member under the end of the boards. The other was to cut the boards back to the last support and weld on a 2x8' piece of steel tread plate. Well, its expensive and impractical to buy a piece of steel tread plate these days. I had a wild idea to maybe just weld on a piece of plane steel plate and scatter weld beads all over it to create some treads. I probably won't but if I did what would be the practicality of that? I've got ten (well nine, one is the top on my welding table) pieces of
4x8x1/4 A36 I bought a while back because the price was right. Some of it is slated for a 60' work bench top down the back wall of my shop, but there will be some left over for other things.