Fatigue Behaviour of T- and X-Joints Made of Square Hollow Sections

摘要

The results of experimental and numerical research in the fatigue behavior of Tand X joints between square hollow sections of which the brace is welded to the face of the chord, without any additional stiffeners, are presented. Experimental results of a project in the low cycle fatigue behavior of axially loaded T joints between rectangular hollow sections were used in this work. The aim of the research is to establish a better design method for the fatigue strength of joints in square hollow sections, based on the hot spot stress method. The results are to be proposed for inclusion in Eurocode 3. In the experimental investigation, the Strain Concentration Factors (SCF) are measured at various locations of the joint for comparison with results of the numerical investigations and S-N curves are determined. The numerical work provides SCF values at weld toes for a range of parametric variations in the joint dimensions. These results form the basis for a set of parametric formulae. These formulae allow the determination of the SCF values at the weld toes of the brace and chord, depending on the nondimensional parameters. The results of tests and formulae are used to check the final validity of the formulae in combination with the S-N lines.