Butadiene Storage Sphere in La Wantzenau, France
The production unit of the company ARLANXEO Emulsion Rubber France, located in La Wantzenau, France, is one of the biggest producers of NBR (nitrile butadiene rubber) synthetic rubberi n the world. Nitrile rubber is resistant to oil and is used for manufacturing cables, gaskets, hoses, brake pads, and safety boots, among other things.
CalculationThe existing storage tanks have been subjected to seismic analysis to comply with the French regulation “Classified Installations for the Protection of the Environment (ICPE)”. Initially, the spheres were designed according to the French seismic code PS92, using the site‑specific response spectrum. However, Eurocode 8 and the Decree of October 4, 2010 have redefined the design spectrum, specifying the seismic rules for installations classified as involving risks. Therefore, a new analysis of the butadiene sphere was required.
Structure and ModelingThe storage sphere is supported by eleven steel columns welded around the envelope of the structure. The columns are interconnected by a bolted circumferential ring. Braces ensure increased horizontal stability of the storage sphere in cases of wind and seismic loads.
A 3D model was created in RFEM structural engineering software. All the components were entered as surface elements (spherical envelope, columns, circumferential ring, braces, gusset plates, anchor plates, and other components). The soil-structure interaction was taken into account by using elastic supports, transferring the stiffness of the deep foundations in each spatial direction.
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SHAPE-THIN determines the effective cross-sections according to EN 1993-1-3 and EN 1993-1-5 for cold-formed sections. You can optionally check the geometric conditions for the applicability of the standard specified in EN 1993‑1‑3, Section 5.2.
The effects of local plate buckling are considered according to the method of reduced widths and the possible buckling of stiffeners (instability) is considered for stiffened sections according to EN 1993-1-3, Section 5.5.
As an option, you can perform an iterative calculation to optimize the effective cross-section.
You can display the effective cross-sections graphically.
Read more about designing cold-formed sections with SHAPE-THIN and RF-/STEEL Cold-Formed Sections in this technical article: Design of a Thin-Walled, Cold-Formed C-Section According to EN 1993-1-3.
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Programs Used for Structural Analysis
Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements
Dynamic analysis of natural frequencies and mode shapes of member, surface, and solid models
Dynamic and seismic analysis including time history analysis and multi-modal response spectrum analysis
Seismic and static load analysis using the multi-modal response spectrum analysis