St. Pauli Elbtunnel:
Masterpiece of engineering
Hamburg – the city of superlatives: The largest port, the largest warehouses, most media companies, the largest entertainment district, the most famous musicals. But it doesn't stop there.
Hafen City also has a masterpiece of engineering to offer: The St. Pauli Elbtunnel, which was commissioned in 1911.
Two tunnel tubes, 426.5 metres long, connect the northern harbour edge at the St. Pauli landing bridges with the Elbinsel Steinwerder island.
Around 45,000 people passed through the road every day on 7 September 1911, when the underwater waterway was commissioned. For example, it was the expansion of the “Gateway to the World” that motivated the construction of the Elbtunnel. The number of workers who had to get from the city to the port and shipyards increased.
The first river tunnel in Europe at the time was a technical sensation and was built under the direction of the builder Otto von Stockhausen. A hydraulically driven drifting plate had drilled the tubes with a diameter of around 6 metres through the ground (blade drifting method).
Around 4,400 workers were involved in the project, shovelling out sand and earth in front of the drill blade. The resulting cavity was secured by riveted iron segments (precursors of today’s Tübbings).
The compressed air process prevents water from penetrating through the sandy substrate through overpressure. Architecturally, the tunnel impressed back then as it does today: An antique-looking round structure with a domed roof on the side of the landing bridges leads to the Elbe crossing. The southern entrance to the island of Steinwerder was severely damaged during the Second World War.
Originally, both buildings had the same design. They only insisted on red brick stones and thus blended in with the image of the surrounding customs and shipyard buildings.
Tuffstone, basalt and granite were used in St. Pauli, which visually matched the landing bridges.
Four cabins for trolleys and bicycles, two small passenger lifts and stairs each lead almost 24 metres down in the shaft buildings. From there, passers-by enter the light-coloured tiled tunnel, which is decorated with stoneware reliefs that show the world of the Elbe with maritime motifs such as sea creatures.
Today, the underwater tunnel has largely lost its infrastructural significance, among other things due to the construction of the New Elbe Tunnel.
However, it is still passing through many tourists, cyclists and pedestrians every day, while it is soon to be permanently blocked for vehicles. As a landmark and popular sight in Hamburg, as well as a sought-after location for events, film shoots and photo shoots, the Old Elbtunnel is an indispensable part of the city.
It has been a protected monument since 2003 and has been awarded the “Historical landmark of engineering in Germany” by the German Federal Chamber of Engineers and Hamburg’s Engineering Chamber since 2011.
A lot of responsibility and a structural challenge for the Hamburg Port Authority (HPA), which plans and supervises the extensive repair work on the St. Pauli Elbtunnel on behalf of the Hanseatic City. The complete Tübbing structure was already exposed and checked in the east tube, rivet and screw connections were replaced and joints sealed.
In addition, the wall tiles, roadway and lighting were renewed or restored in accordance with the historical model in coordination with the monument preservation. There was also modern technical equipment in the tunnel with an automatic counting system, smoke detectors and much more.
After the restoration of the eastern tube was successfully completed and reopened on 26 April, the restoration measures have continued in the western tube since 3 June 2018.
Two stairwells for pedestrians will also be rebuilt as part of the tunnel repair. FIS EM Plus injection mortar from Fisch was used together with an M27 threaded rod to secure the structure, which is about 20 metres high on the south side.
“Even under extreme conditions, such as in areas prone to earthquakes, the chemical fastening system is a safe choice for introducing heavy loads safely into concrete over the long term,” emphasises Arne Saggau, a fisher application engineer in the field, who plays a key role in supporting the project.
