Zurich main station cycle tunnel

Initial situation

A safe and uncomplicated connecting route between districts 4 and 5 will be created by building a bicycle tunnel. This will enable cyclists to reach local public transport even more quickly.

The current shell of the cycle tunnel is a hollow space that runs along the Sihl under the tracks of the main railway station. This tunnel, which was originally intended for car traffic, will be converted into a bicycle tunnel by the end of 2024.

Solution and assessment

In July 2023, concrete was poured for the ceiling of an underpass of the aforementioned bicycle tunnel at the intersection between Konradstrasse and Sihlquai.

The most important aspect was rapid drying, which ensured that all subsequent work steps, such as the application of the waterproofing, could be carried out according to schedule. 

The ceiling was up to 90 cm thick and had a total volume of around 40 m³. The removal of the tracks, re-laying and concreting had to be carried out over the weekend so that traffic could resume on time the following Monday.

In order to keep to the schedule, Concretum^® Q-FLASH 5/20 rapid-hardening concrete was used, which was poured smoothly and on schedule in collaboration with Scheifele.

The set open time of the concrete enabled safe delivery from the EbiRec concrete plant in Rümlang to the installation site and there was sufficient time to place and process the concrete.

The Concretum^® Q-FLASH 5/20 achieved a moisture content of less than 4.0 CM% just 4 hours after concreting. This made it possible to quickly continue with the other work steps, such as the application of waterproofing.