I remember hearing a while back that UAL had problems with the FWD galley area in their 777's and that floor beams were being affected, but I don't know what became of it. - Miamiair
I don't think the floor beams you are talking about are composite. There was a flexing issue at the cockpit to cabin joint. Unfortunately the design was borrowed from the 767, and suffered the same eccentric loading and bending problems that the 767 did. If you go on a 777, you will notice that you have to step up to get in the cockpit. It is that area that was a problem. Boeing / operators noted the problem early and released quite a hefty mod. Kudo's to DL
MTC, they slammed through the first mod in 15 days and worked it down to 10. Their counterparts at another airline took 30 days to do the first and I doubt they ever got much better.
Air transport is just a glorified bus operation. -Michael O'Leary, Ryanair's chief executive