The main purpose of this project is to study the possibilities for increasing the fatigue life of welded steel structures by post-weld treatment (grinding). The results obtained at the moment indicate that considerable increases in fatigue life may be obtained by use of these methods.In the project, the fatigue life is primarily determined by experimental investigations. The project is a part of a common Nordic research project: FE-Design 2003, "Bættre utnyttjande av høghållfast stål genom framtagning av rationell dimensioneringsteknik før komplexa svetsade strukturer".