I have a good friend who has a creek on the back of his property that splits his property. He likes to have access. He did have it via a bridge built by a neighbor. However now that bridge is getting old, and my friend has bought a larger tractor. These two issues don't go well together.
I have a 20' trailer with a 5th wheel hitch. It was built in 1980 and was reinforced and rebuilt when the gentleman I got it from purchased it. (it had a bent hitch). Axles replaced, etc. He had intentiions of pulling his Ford backhoe on it, till he loaded it and weighed it. It was above the rated GCVWR of his truck.
I used it for a few years till I got a Big Tex gooseneck, then it got parked. I have considered removing the axles and putting them under a bumper pull trailer I have.
That leaves a 20' trailer with sides (that will hold a 7k tractor rear wheels)
I proposed that he build two small foundations on each side of the creek and we carefully set my trailer across it using two tractors with FEL's. A pair of ramps similar to the ones on the rear of trailer will need to be fabricated for the front once the 5th wheel hitch is removed. Keeping the trailer elevated at each end will prevent the steel frame from sitting in the dirt, which should decrease corrosion of the frame and give it support.. A rubber mat under the steel might also help with high traffic crossings. (his won't be, but we have them) He will need to replace the flooring of the trailer, as I am sure that it is probably rotten due to the time it has sat unused.
I think it would work just fine as long as the trailer is stong enough to support the load you are putting on it. A good idea before putting the frame over the creek would be to block it in your yard where you can drive over it before going to the trouble of spanning the creek with it. My trailer is overkill for his load, so I wouldn't need to do that.
David from jax