Structural Concrete, Vol. 9, no. 4, December 2008
Fatigue life of short-span reinforced concrete railway bridges
M. Pimentel, Laboratory for Concrete Technology and Structural Behaviour (LABEST), University of Porto, Portugal
E. Brühwiler, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
J. Figueiras, Laboratory for Concrete Technology and Structural Behaviour (LABEST), University of Porto, Portugal
In this paper a parametric study on the fatigue life of short-span reinforced concrete railway bridges is presented. Only reinforcement steel fatigue damage is considered. The objective of this work is to assess the factors that may have a decisive influence on reinforcement fatigue life, to evaluate the consequences of the increasing traffic loads and to identify the research needs so as to allow more accurate fatigue examinations of existing bridges under more demanding traffic conditions. It is concluded that reinforcement fatigue life is mainly governed by the existence of heavy traffic (freight trains) and that it is highly sensitive both to the axle loads increase and to the accuracy in the reinforcement stress range calculation. It is also shown that the current analysis procedures may suffice for economic design of new bridges, whereas in the case of existing bridges more elaborate analysis procedures may be necessary to prove fatigue safety.