barges is build to withstand a lot of forces, The hull "have to be" reinforced to withstand that type of force the receive over the years, the "frame work"is also a tad stronger than you find in for example a cruise ships.
For example in Norway when they was building that huge oil-rig "Statfjord-A" they used similar barge to transport the superstructure onto the pillars.
see in this video at about 1:40, that's the power off.....:
http://www.youtube.com/watch?v=goQSVhNwHTc