It’s difficult to comprehend the magnitude of the waves developed during a major hurricane. The hurricanes that wreaked havoc on the US Gulf Coast left plenty of evidence in their wake of their destructive potential. Offshore structures received considerable damage from the waves and wind. Older platforms which set cellar deck elevations based on older API guidelines were hard hit by the extreme wave heights exhibited by Ivan, Katrina, and Rita.
The damage seen in the picture on the right is from hurricane Rita in which a wave topped the cellar deck. As can be seen in the picture, quite a few large beams have been bent. Current codes are a little unclear on assessing residual strength of deformed members, so we had to improvise.
Our analysis procedure needed a method to compare the results from the FEA model of the deformed beam to an equivalent FEA model of an undeformed beam. The uniform load that will produce an extreme fiber stress equal to 
is applied across the top flange of both the undeformed and deformed beam. The peak stress in the deformed beam is calculated and compared with the peak stress obtained from the undeformed beam:
The ratio should then be a direct measure of the reduction in capacity of the beam.
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