Strength of Welded Connections (Repoert 1)

Yield and Ultimate Strength

Abstract

Recently, steel structures are in a trend to be designed with consideration of their reserved strength in the plastic range. Accordingly, the strengths of welded connections are also to be discussed from this point of view. There are only few papers which dealt with elastic-plastic behavior of welded connections and consequently, present conventional design formulae of welded connections seem to be based on the simple elastic analysis or the experimental results on the fracture strength.
In order-to clarify the elastic-plastic behavior of welded connections, a series of experiments was conducted on cruciform connections with fillet weld under uniaxial forces, pure bending, and pure shear, and their combination. From the results, it was found that the connection showed a sudden reduction of regidity at general yielding and reached its ultimate strength after a large amount of plastic deformation. Therefore, it is very reasonable to discuss the strength of welded connection in terms of the above two points, i.e., yield and ultimate strength.
Theoretical analysis was also made on the above mentioned strength with the aid of plastic analysis method. The results of the analysis well coincide with those of the experiment and locate well the actual sections in which general yielding and ultimate strength are attained. Based on the results of the investigation, design fomulae are proposed for the yield and ultimate strength of welded connection.