The Foundations of the Railway Bridge Over the B25 in Donauwörth-Paper

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The paper describes replacement of a 92-year-old railway bridge over Germany’s B25 road in Donauwörth using accelerated construction. To minimize disruption, the new 28 m bridge was built beside the existing structure while railway operations continued. Contractors then had only a 10-day track possession to demolish the old bridge, slide the new one into place, rebuild the track, and restore service.<br /><br />Soft, highly variable soils near the surface posed a risk of differential settlement. The project therefore used rigid inclusions to transfer foundation loads into deeper, dense to very dense sand. Non-grouted ductile iron piles (DIPs) were selected for their rapid installation and immediate load-bearing capability. The design included a granular load-transfer platform reinforced with geogrid, and conservatively assigned the full foundation load to the piles. The piles averaged about 10 m in length and were designed for temporary construction and sliding stages as well as the bridge’s permanent service life.<br /><br />A total of 398 DIPs—approximately 4,000 linear metres—were installed in just 60 hours. After the load-transfer platform and temporary thrust beds were completed, the roughly 4,000-tonne bridge was slid into its final position in a three-hour operation on January 28, 2024. Track reconstruction was completed by January 31, and the bridge reopened to railway traffic on February 1. The case demonstrates how rapidly installed ductile iron piles can support tight construction schedules while controlling settlement in challenging ground conditions.

Keywords

railway bridge replacement

accelerated construction

Germany B25 road

Donauwörth

ductile iron piles

rigid inclusions

settlement control

bridge sliding operation

track possession

geogrid reinforced platform