Determination of localized stresses in the shell above anchor bolt chairs attachments of anchored storage tanks

• Three methods were used to determine the localized stress above anchor bolt chairs.
• Tank height, diameter, shell thickness and chair height were studied using FEM.
• Linearization and extrapolation methods obtained equivalent results for this study.
• The utilization ratios obtained using AISI and ASME methods are comparable.
• The AISI formulation computes more conservative stresses for big diameter tanks.

Anchor bolt chairs are attachments widely used to control the overturning stability of storage tanks subjected to external and internal forces. This paper discusses three different procedures based on mathematical equations, stress linearization and stress extrapolation to determine the localized stresses occurring in the shell above the chairs due to wind load. Several finite element models were built to study the effect of four different parameters such as the tank height, the tank diameter, the shell thickness and the anchor chair height. The results of the three methods are compared in terms of the localized stresses obtained from each one as well as in terms of the utilization ratio of the shell material.