Product
As part of the complete renewal of the Cityring Lucerne, several challenging construction projects had to be carried out. Traffic through the city was severely affected by the construction measures. It was a major concern to shorten the closure periods. The intermediate ceiling in the Sonnenberg tunnel had to be constructed in just one weekend closure. This included formwork, reinforcement, concreting, and stripping. The time window from concrete production to reaching a compressive strength of 40 N/mm² was a mere 10 hours. Nevertheless, the concrete had to have an open time of 3 hours for pumping.
The ambitious solution concept was implemented with an adapted variant of Concretum® Q-FLASH 2/20. The work schedule was very detailed and tailored to the concreting work. Excellent planning and very good cooperation between the concrete producer, concrete pump, and contractor were the key to success. The concrete could be pumped and placed without any loss of consistency for 3 hours. With the beginning of the setting process, a rapid strength development started. The formwork could therefore be lowered as planned, and the tunnel could be reopened to traffic on Monday morning.
Summary of the Challenge and Solution:
The construction team faced the challenge of completing a complex concrete structure in a very short time frame. They were able to achieve this by using a specially formulated high-performance concrete that developed strength rapidly. This allowed them to remove the formwork quickly and reopen the tunnel to traffic on schedule. The success of the project was attributed to careful planning, coordination between different teams, and the use of innovative materials.
Product
Country
Switzerland
Construction Period
2011 February – 2012 February
Client
Federal Road Office (ASTRA), Zofingen Branch
Construction Company
ARGE Cityring c/o Anliker AG, Contractor and Designer: IG LUCI, c/o Emch+ Berger WSB AG
Concrete Producer
Belag und Beton Rothenburg
Field of application
Road traffic areas
Paving method
Pumping