I know I am a little late in this conversation, but that never stopped me before!
Load+Trailer= ~ 50,000
Maximum Legal weight on Tandem Set = 34,000
Minimum tongue weight for trailer to be legal = 16,000
From looking at the picture, I am guessing the load was almost exactly centered over the trailer tandems, meaning there was no weight added to the truck and that you have close to 50,000 on the rear axles (which is likely exceeding the tire sidewall ratings as well).
Any doubts would be removed by weighing the trailer axles, and then finding out how much weight needed to be transfered forward to reach 34,000.
I am an "expert" on this subject and the math involved because I just went through it with a 47,000# paver on a tag-trailer (~50,000 combined) behind a 10-wheeler with a walking beam rear tandem axle.
For years they hauled it with the weight mostly on the trailer axles (42,000), exceeding the ~40,000 tire rating as well as the 34,000 axle limits.
The math said I might be able to pull it forward enough to put 16,000 on the hitch (rated at 18,000...) and be legal. Went to the nearby quarry scales and moved it. The walking beam pivot point was so far from the hitch, it transfered about 5,000 off the front axle onto the rear making the rear truck tandems overweight! Maybe if it wasn't a Mack and had air-bags or something it would have worked. Also it removed steer weight so when I was turning on gravel and gave it some go-pedal, the front end picked up and went straight... In any case, something bigger will have to haul it, or they need to get me a 3-axle tag. (haven't told the boss yet, waiting for him to be in a good mood so I can kill it...) :drinkup