The residual lifetime of steel bridges under the action of fatigue and corrosion effects

Decades-old steel bridges have to face the unfavourable environment that causes the ageing and deterioration of material properties. Moreover, especially railway bridges, which are famous for permanent resistance to heavy movable load, are exposed to large number of stress ranges that may lead to fatigue damage. Combination of both phenomenon has significant impact on the condition of bridges and their remaining service life. The subject of the proposed paper is observation the response of steel bridge structures containing construction elements weakened by corrosion on cyclic load. For the purpose, the series of laboratory fatigue tests were performed on samples of riveted connections. Specimens with various level of corrosion weakening had been taken from historical railway bridge and were loaded by cycling force in tension subsequently. The laboratory tests were supported by numerical analysis. This paper presents knowledges gained from the study that was focused on how to take into account the combined effect of degradation process and fatigue. The evaluation of the tests indicates that the service life of members may be significantly reduced due to fatigue. The developed relationship between corrosion loss and reduced detail category is statedThe research reported in this paper was supported by the Grant Agency of the Czech Technical University in Prague, grant No. SGS17/126/OHK1/2T/11 "Changes in fatigue behaviour of steel bridge structures weakened by corrosion" and by COST CZ (LD) project of the Ministry of Education, Youth and Sports (No. LD15127).