Maintenance of the SOB Bridge Walketobel

Project

On behalf of SOB, the vaulted Walketobel Bridge was renewed on the railway section St. Gallen Haggen – Herisau. To minimize the closure time, a concept was needed that allowed the construction work to be completed within a weekend closure, with the bridge being reopened for train operations on the following Monday.

The waterproofing of the internal structure was no longer effective. To prevent further damage to the existing structure, vaults 1 and 2 of the bridge were re-sealed, and the track bed was renewed.

The bridge is 35 meters high and 118 meters long. Due to the challenging topographical and geological conditions, the concrete was transported 35 meters in height using a skip. To carry out the complex construction work within the set timeframe, the rapid-setting concrete Concretum^® Q-FLASH 2/20 was used.

Customer benefits

Thanks to the fast curing of Q-FLASH, all concrete work was successfully completed within a single weekend. The Concretum^® Q-FLASH 2/20 was used for the renewal of the track bed. Despite very intense sunlight and heat during the concreting work, a workability time of about 2 hours was ensured, and a compressive strength of 20 N/mm² was reached within two hours of the start of curing.

As there was no cement silo available at the nearby concrete plant, the 12 m³ of concrete was produced on-site in three ready-mix trucks. The closure time of the bridge was minimized. The fresh concrete consistency was adjusted variably, ensuring smooth placement.