The rated life span is more on the lines of 50 years... however, they may last double that... They are made out of a special concrete that is reinforced, and super strong. I used to know more details on that... but... it's Sunday, I'm on vacatation... and so is my brain.
For maintenance... twice a year, the beams get X-Rayed and phyically inspected to insure that they are in proper shape.
In addition to that, last year, there were some sections of the beam that got resurfaced. They would mill down the concrete about an inch or two, and then resurface it with new concrete. It took them about 5-8hrs just to do 1-2ft of milling.
We also do periodical sand blasting and pressure washing to clean the beams. If you go now, you'll notice a lot of the beams in guest areas are super clean, and look brand new.
Rest assured... those beams are A-OK.
