Abstract:

This study analyzes a 3000m³ CO₂ spherical tank under seismic fortification intensities of 6-degree (0.05G), 7-degree (0.1G, 0.15G), 8-degree (0.2G, 0.3G), and 9-degree (0.4G), adopting three methods including the current GB/T12337, the methodology described in reference [4], and finite element analysis (FEA). The horizontal stiffness, natural vibration period, seismic response coefficient, wind vibration coefficient and combined horizontal load of the spherical tank are calculated. The stresses of structural components such as pillars, tie rods (with the requirement of equal strength design for lug plates, dowels, and tie rods) and anchor bolts are calculated and checked. By comparing the calculation results of these three methods, it is found that the calculation results according to the current GB/T12337 standard differ greatly from those obtained through FEA. The calculation results of the reference [4] are similar to those of FEA and just meet the structural requirements of the GB/T12337 standard. Both the reference [4] and FEA methods indicate that the stress of pillars does not meet the requirements of strength and stability. The equivalent stress of pillars calculated by FEA is 47.2% greater than that calculated by the GB/T12337 standard. As the standard for spherical tanks is currently under revision, it is recommended that more precise computational methods should be adopted in this revision to ensure the safety of standard-designed spherical tanks under all operating conditions.

Key words: spherical tank, spherical shell, pillar, tie rod, dowel;anchor bolt, seismic fortification intensity, natural vibration period, seismic and wind horizontal loads, horizontal displacement of the lower pole of spherical tank