Repair of the Bremen-Burg railroad bridge

At almost 150 years old, the Bremen-Burg railway bridge is considered one of the oldest operational traffic bridges in Germany. Age-related deterioration was detected in the structure, and Deutsche Bahn (German Railways) decided to carry out repairs. These included refurbishing and strengthening the central bridge pier with MC´s Nafufill GTS HS rapid.

 

The Bremen-Bremerhaven railway line runs over the Bremen-Burg railway bridge. The route, which crosses the River Lesum – a tributary of the Weser – on the double-track truss bridge, is not only important for regional rail traffic, but especially for the transport of goods to and from the port of Bremerhaven. Every day some 80 freight trains and 50 passenger trains travel across it.

 

Narrow timeframe for rehabilitation work
The 80 m long bridge with a passage height for ships of three metres at normal high water was built in 1872 on huge concrete piers. Local politicians began voicing fears in 2015 that the ageing railway bridge might no longer be sufficiently stable. Earlier, passers-by had reported damage to the massive pier structures on which the construction with its steel superstructures rests. At low tide, it became apparent that the lower section of the central bridge pier had been eroded by the waters of the Lesum, which flows very fast at this point. Deutsche Bahn reported that the stability of the bridge, which is regularly inspected, was not at risk. Nevertheless, they decided to institute timely concrete repairs to the central pier so as to ensure the full long-term availability of the bridge. This turned out to be a particularly demanding task: Due to the high tidal range of three metres, the bridge pier could only be strengthened when the river was at low tide – a very narrow timeframe.

A safe solution for tidal concrete structures
The Oldenburg-based company Ludwig Freytag GmbH & Co. KG was selected to carry out the work. And it began the rehabilitation procedure in July 2021. Due to the tidal range and the high flow velocity of the water, the use of standard products would have resulted in considerable additional expense arising from the necessary installation of sheet piles and provision of a special dewatering arrangement. So the decision was made in favour of the fast-hardening speciality concrete replacement Nafufill GTS HS rapid from MC. This polymer-modified, low-shrinkage concrete replacement product is highly sulphate-resistant, chloride-proof and resistant to temperature, frost and de-icing salts. And it can be applied by dry spraying. Nafufill GTS HS rapid fulfils the requirements for mortar class R4 laid down in EN 1504 Part 3 and is thus also approved for concrete strengthening in structurally relevant areas. The concrete replacement product not only hardens very quickly, it also develops resistance to attack and can withstand permanent water exposure after just one hour. These properties make Nafufill GTS HS rapid a fast, but also a safe and sustainable solution for the repair of saltwater- and fresh-water-exposed tidal concrete structures.

 

The repair of the bridge pier concrete was thus implemented in the shortest of times, upgrading the structure for trouble-free train travel in the coming decades.