AVALIAÇÃO NUMÉRICA DE VIDA À FADIGA DE LONGARINAS DE PONTES UTILIZANDO MODELOS DE LARGA ESCALA

Resumo

Fatigue can be characterized as a form of failure of elements subject to cyclic stress/
deformation throughout their lifecycle. The phenomenon occurs mainly in mechanical machines,
bridges, aircrafts, among other kind of structures. In this context, the study of fatigue is of fundamental
importance for the design of civil engineering structures, since most of the reported failures can be
related with fatigue. Particular for bridges, the phenomenon is the main responsible for the decrease of
the bridge’s life, due to the increase of traffic volume and vehicles weights. In this work, the nominal
stress method and the hot-spot stress method were used to assess the fatigue strength S-N curves of three
different large-scale girder bridge specimens. The girders were modelled using shell and solid elements
and the models were calibrated against fatigue experimental tests available in the literature and
performed mainly in the Fritz Engineering Laboratory of the Lehigh University, Pennsylvania, USA.
The fatigue assessment carried out obtained stress results similar to that found in bridges. The
experimental lives were compared with the lives obtained from the numerical models. Therefore, this
work emphasizes the importance of the fatigue limit state, either in the design stage or for evaluation of
existing bridges.