Abstract
Large aboveground oil storage tanks are unanchored and rest freely on flexible foundation. The shell-to-annular joint of unanchored oil storage tanks will uplift due to strong seismic excitation, and a large plastic strain occurs in this joint. This paper presents the elastic-plastic, large deformation behavior of the uplifted shell-to-annular joint using axisymmetric finite element analysis. In the analysis, the uplift behavior is assumed to be axisymmetric. The constitutive equation is based on the J2 flow theory with the kinematic hardening rule. The updated Lagrangian approach is used for the formulation of large deformation. The strength of the shell-to-annular joint in a large tank with capacity 90, 000m3 is reported. While deformation, stress and strain of the joint at uplift are described, it verifies also about mesh division, relation between equivalent stress and equivalent plastic strain, and partial penetration welding.
