Eurocode 8 define an Overstrength factor that should be considered for elements design.
The consequence of this factor consideration, is described for instance in the following articles:
6.2.3, 5.4.2.2, 4.4.2.6, 5.2.2.2, 6.3.2 and 7.3.2 (more other articles may exists).
http://forums.autodesk.com/t5/Robot-Structural-Analysis/Surcapacit%C3%A9-des-fondations-dans-le-calc...