Construction of the new RBS railway station in Bern
Bern has the second largest railway station in Switzerland. The existing RBS railway station was opened in 1965 and is capable of handling around 16,000 passengers. Today, some 60,000 people use the RBS railway station every day. Compared to 2016, the capacity utilisation of Bern station as a whole is expected to increase by a further 39% by 2030. The old RBS station cannot be expanded, so a new RBS station will be built under tracks two to seven. This will consist of two large underground halls, each with two tracks and a 12-metre-wide central platform. Ultimately, this will provide significantly more space and comfort, and will also allow for trains to run more frequently and longer trains.
How is Marti involved in the construction of the new facility?
Marti will be working on phase 1.3. Thomas Heid, site manager for phase 1.3, explains: "You could say that phase 1.3 is the key element of the entire project." Phase 1.3 consists of two caverns: the north cavern and the south cavern. The caverns are 199 and 209 metres long respectively. They are both 17 metres high and 23.8 metres wide. Words alone cannot convey the scale of these dimensions. When you visit the site for the first time, you are overwhelmed by the sheer size of the caverns. By way of comparison, a seven-storey building would fit into the caverns in terms of height. Now that’s impressive. Students will have the opportunity to visit the caverns in October 2024 as part of the Concrete Colloquia 2024. The open day will be held on 7 September 2024. Anyone who is interested can register for this day.
That's already quite impressive, but there's more to it than just that.
Art in construction and in the tunnel
Concreting the inner vault with ribs is a technically very demanding task. The reinforcement was pre-assembled in the cavern during the assembly of the vault formwork carriage. The vault blocks are now being concreted in several phases using the impressive formwork carriage, which was developed and built by Marti Technik AG in close collaboration with Marti Tunnel AG. Each section of the vault is five metres long. The fluctuations in the raw materials, the blocking of the fibres between the reinforcement and the logistics chain (multiple handling, free fall of approx. 25 m) as well as the weather conditions, which varied greatly over the course of the project, have prolonged the development and new paths had to be taken. A stable mixture for the vault concrete was developed and successfully tested with the newly developed additive "Quantum Compound" from Baustoffpark Walliswil. Marti is confident that they can satisfy the high aesthetic expectations and is looking forward to the challenges ahead with this unique ribbed vault.
The formwork carriage is truly a 260 tonne masterpiece. It took around nine months to plan and produce the parts. Some 20 trucks were needed to transport the individual parts to the construction site. The parts were then lowered into the cavern via the shaft, where ten employees assembled the formwork carriage over a period of several months.
Construction of the formwork carriage began in December 2023 and the first block was concreted in March 2024. One block contains around 80 cubic metres of the self-compacting fibre concrete specially developed for this purpose by Marti and is five metres long, 20 metres wide and 16 metres high.
The specifications in terms of geometry, the required tolerances and the desired exposed concrete properties call for the highest levels of expertise, experience and commitment from everyone involved – from planning, construction and concreting to the very tricky stripping process and curing.
The formwork carriage is 100% electrically powered. It sits on four hydraulically driven bogies. The lifting supports that are used to position the height and position of the carriage and thus the formwork to within millimetres stand on these. All of the functions and movements are hydraulically controlled by the employees from the central control station.
The team is confident that it will be able to satisfy the high aesthetic expectations and is looking forward to the challenges ahead with this unique ribbed vault.
Conclusion
The construction site in the heart of Bern allows Marti to capitalise on the broad knowledge and skills of all its employees. Everyone involved puts in a remarkable performance every single day. Federal Councillor Albert Rösti summed it up perfectly at the breakthrough on 23 June 2023:
"I can barely imagine the amount of work that everyone involved has done here. They are the ones who have achieved this, the credit is all theirs. You all deserve a big round of applause."
I can barely imagine the amount of work that everyone involved has done here. They are the ones who have achieved this, the credit is all theirs. You all deserve a big round of applause.
Facts & figures
Dimensions of the caverns (Lot 1.3):
- Length: 199 m (north) and 209 m (south)
- Height: 17 m
- Width: 23.8 m
Formwork carriage :
- Weight: 260 tonnes
- Dimensions of the vault blocks: 5 m long, 20 m wide, 16 m high
- Concrete per block: 80 m³
- Drive: 100 % electric