Abstract
The structure of buses and coaches are usually made by steel profiles and welded joints. The conventional analysis and design of steel frames making use of finite element models (FEM), treats the connecting joints as either perfectly rigid or pinned. However the connections used in steel frames structures have semi-rigid deformation behaviour that can influence the complete structure . It is not practical to analyze complicated finite element models that simulate the connection as wel l as the whole structure. Because of this, It becomes necessary to characterize real stiffness of joints and to incorporate it in simplified simulation models.