Analysis of fatigue behaviour of a bridge welded structure

Abstract

Results of extensive experiments involving the fatigue behaviour of welded structures which are a part of the "Gazela" bridge in Belgrade, Serbia, are presented in this paper. After non-destructive testing of these structures, crack-like defects were detected, and welded plates containing them were taken out for the purpose of destructive testing. This testing involved tensile tests, impact testing using an instrumented Charpy pendulum and fatigue tests, from which the S-N curves were obtained. Based on these results, fracture mechanics parameters were determined, including crack tip opening, critical J-integral, stress intensity factors and critical crack length. In addition, fatigue tests, which involved four-point bending of standard Charpy specimens provided da/dN-Delta K curves, which were then used in order to determine Paris Law coefficient, C and m. Obtained results are of great importance in order to better understand the behaviour of large-scale welded structures subjected to both static and dynamic (cyclic) loads, such as bridges.