BUCKLING RESPONSE OF CORRODING GROUND BASED STEEL STORAGE TANKS UNDER SEISMIC LOADING

Steel liquid storage tanks are h ighly susceptible to corrosion from within. She ll corrosion significantly alters the seismic response of grou nd-based cylindrical steel storage tanks. Investi gations on the effects of imperfections in thin cylindrical s hells show that large local buckling can occur at the locations of the corrosion-induced imperfections. In this paper, a numerical study is conducted to investigate the effects of internal shell corrosion on the dyna mic buckling of three cone roof ground-based, ste el cylindrical tanks with height to diameter ratios (H/D) of ۰.۴۰, ۰.۶۳ and ۰.۹۵, subjected to horizontal seismic base excitations. Internal corrosion is considered as a time dependent uniform thinning of the wall at the upper and the lower parts of the tank. Detailed numerical models of the tank-liquid systems at diffe rent stages of corrosion degradation are subjected to two r epresenting accelerograms and for each model the critical peak ground acceleration (PGA) for dynamic buckling of the shell and its associated mode of fa ilure are evaluated. It is found that in all three tanks, the critical PGA is markedly reduced with thinning of the shell, irrespective of the type of ground input. The buckling mode of failure of the tanks also changed from an elastic diamond-shaped failure at the top of the shell to an elasto-plastic elephant foot type failure near the base, after ۱۰ years for the shorter tanks (H/D = ۰.۴ and ۰.۶۳) and after ۱۵ years for the tallest tank.

کلیدواژه ها:

SteelStorage Tanks ، Corro sion ، Buckling ، Seismic Response ، Hydrodynamic Effects ، Imperfections