Structural monitoring for asset management of railway bridges

This paper demonstrates the advantages of site monitoring to aid modelling of the existing condition of a railway bridge with structural problems and to assess the current structure and future remediation. The authors undertook monitoring and assessment on a major 28-span post-tensioned prestressed concrete box-girder bridge on a strategically important railway line in India. The bridge exhibited significant longitudinal web cracking, which restricted its load-carrying capacity to relatively light urban passenger rolling stock. Monitoring of rail traffic was supplemented by full-scale load tests for both static and dynamic loading. Optical strain sensors and electric resistance strain gauges were used for strain measurement and piezoelectric sensors were used to record accelerations. Sensors were also installed to record crack widths. A programme of numerical modelling was undertaken with finite-element models developed for both cracked and uncracked conditions. Results were compared with field data and the models were then refined to achieve a representative model for use as a predictive tool for future assessment and structural remediation of the bridge.