Welded joints in structures in earthquake conditions

The research project on '''' Welded joints in structures in earthquake conditions'''' is an applicative project studying welded joints between story beams and vertical beams in building subjected to earthquake loads. Two equal models of the welded structure were made. They were both tested by low cycle fatigue, which represents an earthquake load. The influence of a welding process on fatigue was studied, weld sizes being in both models the same. By program controlled hydraulic system providing force pulsations, large deformations in the structure and the fatigue fracture of the welded joints were achieved in four load cycles. Force - deformation diagrams show the input of mechanical energy into the welded joint. The greater width of the hysteresis loop and the greater number of the loops show the greater resistance of welded joints to the earthquake load. It was noticed that the difference between the two welding processes did not affect the resistance to earthquake load.