A Review of International Guidelines for Railroad Bridges Focusing on Fatigue Assessment and Structural Health Monitoring

Abstract

Most steel bridges designed between the early 19th century and the mid-20th century were built of mild steel plates and profiles with riveted joints. The assessment of existing railroad bridges has become increasingly important in railroad infrastructure management. Many riveted bridge structures have exceeded their original design lifespan, requiring assessment to ensure structural safety and reliability requirements. The remaining fatigue resistance is often a dominant factor during assessment. Since historical construction methods, such as riveting instead of welding, differ from modern techniques, infrastructure operators seek tailored solutions for evaluating these structures. Structural Health Monitoring (SHM) is gaining prominence as a tool for enhancing assessment accuracy and supporting decision-making. There are already various guidelines from railroad operators available. However, the integration of SHM in these guidelines is very different. Therefore, this study compares different assessing guidelines for existing railroad bridges, focusing on SHM integration and fatigue assessment for riveted steel bridges. The guidelines analyzed indepth include “DB InfraGO AG. Handbuch 80500 – Tragsicherheit bestehender Eisenbahnbrücken“ (DB InfraGO AG. Manual 80500 – Structural safety of existing railroad bridges), “ÖNORM B 4008-2. Bewertung der Tragfahigkeit bestehender Tragwerke. Teil 2: Brückenbau“ (OENORM B 4008-2. Assessment of the load-bearing capacity of existing structures. Part 2: Bridge construction), and “Berliner Verkehrsbetriebe. Richtlinie zur Bewertung der Tngenieurbauwerke im Bereich der U-Bahnanlagen der Berliner Verkehrsbetriebe“ (Berlin transport company. Guideline for the assessment of engineering structures in the subway system of the Berlin transport company), additionally a US guideline will partly be considered. The comparison identifies differences, similarities, and gaps in current reassessment methodologies, particularly in fatigue assessment approaches and SHM applications. These results may form the basis for the development of harmonized recommendations for assessment of existing riveted railroad bridges.