Senseviadukt - Viaduct over the River Sense

Initial Situation

The 95 year old SBB railway viaduct over the river Sense, connecting the two cities Bern and Fribourg, needed to be fully overhauled. By using Concretum^® Q-FLASH 5/20 rapid-hardening concrete, the extensive concrete work was completed in just seven days and therefore the disruption of the railway line was reduced significantly.

For the reconstruction of the bridge, the SBB shut down the line for 21 days. In order to carry out the complex construction work in the designated time frame, large quantities of Concretum^® Q-FLASH 5/20 rapid-hardening concrete were used 24 hours around the clock.

Solution and assessment

Due to the rapid strength development of the Concretum^® Q-FLASH 5/20 concrete, it was possible to tackle the work steps in shorter periods of time. For example, the formwork for the new retaining wall was stripped only 6 hours after the start of the pour.

The bridge deck trough, including the webs, were cast in one pour of 570m³. The concrete was delivered in two different consistencies and consequently could be pumped as well as skipped with the help of a crane. Due to the tight delivery schedule, two batch plants were used simultaneously for the concrete production. This required very thorough logistical coordination. Therefore, each batch plant produced concrete according to a designated mix design for each specific structure, namely bridge deck trough including webs, retaining wall and piles.