Integrated Static–dynamic Assessment and Field-validated External Prestressing Strengthening of an Aging Steel Railway Bridge

Abstract The BH 25 steel truss railway bridge in Garut, Indonesia, exhibited a deviation from its intended camber during construction, raising concerns regarding its structural performance. This study presents an integrated assessment combining full-scale static and dynamic load testing with calibrated finite element modelling. A 90-ton CC206 locomotive was used to evaluate deflection and dynamic response. While the bridge satisfies serviceability requirements, a reduction in global stiffness is identified from its vibration characteristics. To mitigate this issue, an external prestressing system was implemented as a strengthening measure. The results confirm that the proposed intervention effectively restores camber and enhances dynamic performance. The study highlights the value of integrating field measurements with validated numerical modelling within a unified framework for both assessment and strengthening evaluation. This approach provides a practical basis for performance-based rehabilitation of steel railway bridges under operational conditions.