What is the max certified g limit - 2.5g? I can't see that landing being more than 7.5g. I agree with the previous poster's comments about g force varying throughout the structure.
Please...
The airworthiness requirements, FAR 25 for transport category airplanes, are all on the web.
Here is a link and here's the basic requirement for the landing gear.
"Sec. 25.473 Landing load conditions and assumptions.
(a) For the landing conditions specified in Sec. 25.479 to Sec. 25.485 the airplane is assumed to contact the ground--
(1) In the attitudes defined in Sec. 25.479 and Sec. 25.481;
(2) With a limit descent velocity of 10 fps at the design landing weight (the maximum weight for landing conditions at maximum descent velocity); and <....>"
So the gear must withstand a 600 fpm descent rate as the service limit load, and in the certification tests it must pass one test at ultimate loads corresponding to 900 fpm. Note also that there are a number of conditions attached to those requirements, in reality it's not just that simple number.