The Consistent Stiffness Method
ShellDesign includes a special developed feature where ShellDesign has the capability to include the non-linear material behaviour of reinforced concrete into the structural FE analysis. The method is called "the Consistent Stiffness Method" (CSM) and was presented and described at the fib Symposium in PRAGUE 2011. The method is based on an iterative linear elastic FE analysis in interaction with Sestra (SESAM, DNV software). The method is a more efficient alternative to running non-linear FE analysis programs and has the added benefit of performing a code check without extra effort.
The method is extensively tested and verified. The accuracy of the method has been tested with hand calculations, by comparison with other full non-linear programs and experimental tests in addition to demonstration examples, in which good correlation has been demonstrated.
The consistent stiffness method has lately frequently being used to document capacity of the Condeep's in the North Sea in relation to life extension and new design conditions. The advantages of ShellDesign have also been demonstrated for concrete offshore structures in arctic environment where there is a need to document strength for both sheet ice and ice bergs. ShellDesign has also been used for onshore industrial purposes such as cooling towers subjected to high temperature variations.
CMS was used to document capasity in relation to life extension and new design conditions for the Troll A concrete platform