The advantages of MEVA’s support bracket concept: faster construction progress, high cost-effectiveness
In Vienna, an important future-oriented project for public transport is being developed: the central transfer node in the inner city underground network. The expansion in the middle of the city centre requires tight construction planning, optimal processes and clever solutions from the responsible Arge U2xU5.
MEVA cantilever concept plays out its strengths in the tightest of spaces
Austria’s capital will soon break the mark of 2 million inhabitants and traffic is already reaching its limits every day. The city of Vienna is therefore expanding its public transport network. Nearly completed development projects, the gap is being filled with the expansion of the U2xU5 intersection in the busy centre. The new line of the U5 line is scheduled to be completed in 2026, the modernized U2 in 2028. The centrepieces are the new Rathaus station, which is currently being built underneath the previous station, 30 m below street level, as well as the nearby Frankhplatz stop. The construction in the city in full operation, between countless tunnel pipes and underground pipes, the general problem of space and the corresponding logistical difficulties demand a lot from those responsible.
Reliably calculated with MietePlus
The Arge U2xU5, a consortium of the construction companies Swietelsky, Habau and Hochtief, requires compact and flexible systems due to the limited space available underground. The wall heights are around 3 to almost 9 m. MEVA supplied support solutions for single-headed formwork of attachment shells with AluStarTec and Mammut as well as triplex inclined supports – in the complete MietePlus package. The customer thus has calculation security over the entire project, because in addition to rental and logistics, all services such as cleaning and repairs are included.
In 2022, the beams and floor plates for the shafts up to 30 m deep were produced. Partially, work was done in a lid construction so that the terrain surface was quickly usable again for traffic. All the necessary anchoring parts were planned, delivered and installed. By 2025, concreting of the extension shells on platforms and entrances will take place. The concrete is mainly fed to the formwork via fill nozzles and compacted by means of a compressed air external vibrator.
Unique cantilever concept
Around 550 m of walls are concreted at the Frankhplatz and Rathaus stations. Constantly changing heights require numerous adjustments to the single-headed formwork and support in tight spaces. With the help of a unique feature of the MEVA support structure, considerable time is saved with minimal effort in the Vienna underground: The formwork is placed horizontally in front of the sturdy support structures STB 300 Plus and STB 450. Changing heights can now be easily increased or decreased in small steps, depending on the available element widths.
Usually, even with small height adjustments, a structure consisting of formwork and support bracket would have to be completely dismantled, supported and re-assembled. An unnecessary effort, because the advantages of MEVA’s support bracket concept are obvious and delight every civil engineering company: faster construction progress, high cost-effectiveness.
The resulting loads are distributed according to the requirements. Partly the support is only anchored downwards, partly downwards and upwards. The MEVA support bracket can also be used as a support if required. This reduces the load on the intermediate decks, reduces the effort and costs. For statically effective load bearing, Triplex SB heavy-duty supports are fixed to the attachments and outriggers of the STB in the floor plate. If there is no room for it on the floor, the flexible Triplex SB are simply fixed to the opposite wall or ceiling.
STB supports are compact and can be easily moved by crane – or, as in this project, operated with castors. Only 2.45 m deep, the STB 450 are transported by truck and stored in a space-saving manner. With the help of STB attachments, formwork up to a height of 13.50 m can be reliably supported
Visible concrete for all
The new stations at the Town Hall and Frankhplatz are designed to make people want to switch from the car to public transport. Concrete surfaces with high design requirements will flatter the eyes of the observer – with exposed concrete surfaces in S3/A3 according to ÖNORM B 2204 or with SB3 requirement, smooth or with joint pattern. The alkus all-plastic panels fitted as standard in all MEVA formwork pay off here. (Fotos ® Arge U2xU5)
Systems used:
- Special constructions
- Wall formwork Mammut 350
- Wall formwork Mammut XT
- Wall formwork AluStar
- Support brackets STB and SK
- Bevel supports TriplexSchrägstützen Triplex.
Project details:
- Construction companies: Arge U2xU5: Swietelsky, Habau, Hochtief, Vienna
- Builder: City of Vienna
- Architect: Zechner & Zechner ZT GmbH, Vienna (A)
- Project: Arge U2xU5 City Hall / Frankhplatz, Vienna, Austria
- Formwork design: MEVA Schalungs-Systeme Gesellschaft m.b.H., Pfaffstätten, Austria.
