You mentioned the model number, but not the make. Have you been in contact with the manufacturer? There's a pretty good chance that they'll stand behind and pay for the reapirs as it's a 2011 camper.
I'm no structural engineer, but I look at those cracks located between the axles, it looks like failure due to flexing with the axles being the pivot. It almost seems that the I beam design was insufficient for the length and weight of the camper.
Nights camped in 2013 - 55, 2014 - 105, 2015 - 63