Structural assessment of concrete railway bridges

Paper i proceeding, 2008

The work presented provides enhanced assessment methods that are able to prove higher load-carrying capacities and longer fatigue lives for existing concrete railway bridges. It was performed as a part of the EU-project Sustainable Bridges. The results are implemented in the Guideline for Load and Resistance Assessment of existing European Railway Bridges, see SB-LRA (2007) and are reported in detail in a background document, see SB4.5 (2007). The work presents improved methods for the determination of in-situ material properties, for deterministic as well as probabilistic assessments. Advanced methods for structural analysis are presented, e.g. regarding combined shear, torsion and bending interaction. Recommendations are given regarding redistribution of sectional moments and forces obtained from linear finite element analysis. One main objective was to facilitate the use of non-linear analysis for structural assessment. This provides the greatest potential to discover any additional sources for load-carrying capacity, and gives a better understanding of the structural response. Another main objective was to provide methods to assess the remaining structural resistance of deteriorated concrete bridges. Recommendations are given on the effect of corrosion and a methodology is presented for assessment of remaining fatigue life, with emphasis on short-span bridges and secondary elements.