Pier formworks - Line 15 of the Grand Paris Express

Line 15 of the Grand Paris Express is one of Europe’s most ambitious infrastructure projects. It will connect 75 km of underground network around Paris and transform transport in the metropolitan area. One of its key sections is Saint-Maur–Créteil, an area where civil engineering has had to contend with considerable depths, complex geology and highly demanding vertical structures.

SAINT-MAUR TO CRÉTEIL SECTION

Comprising 36 stations, this project forms part of the Grand Paris Express scheme, which is due to be completed in 2030.
Saint-Maur–Créteil station connects with the RER A, one of France’s busiest rail lines. This requires robust, deep structures built to high safety standards.

CONSTRUCTION CHARACTERISTICS OF THE SECTION:

• - Average depth: 25–45 metres.
• - Construction method: TBM tunnel + stations excavated in shafts.
• - Key structures: large-diameter piers, internal walls, intermediate slabs and ventilation shafts.
This environment necessitates the use of high-strength formwork that is adaptable and capable of delivering finishes of architectural quality.

STEEL FORMWORK

The construction of deep-level stations requires formwork systems capable of withstanding high concrete pressures, allowing for rapid assembly, and ensuring a flawless finish. The following are primarily used in this type of project:

• - Circular steel formwork
• - Rectangular modular formwork
• - Guided and self-supporting climbing systems
• - Special structures for complex geometries

PIER FORMWORKS

Under the engineering supervision of our client Coffrage & Quipage, we manufactured a total of four sets of pier formwork, each fitted with working platforms on all three levels.

It was quick to assemble using locking bolts and had a smooth finish, making it ideal for exposed structures.

Steel formwork allows for rapid concreting cycles, provides rigidity at great heights and can be adapted to any type of geometry, even highly complex ones.

TECHNICAL CHALLENGES OF THE SAINT-MAUR – CRÉTEIL SECTION

Deep excavation sites such as this one present mobility challenges for certain types of machinery. Easy-to-assemble metal systems are therefore ideal for carrying out the work.
Underground logistics are also complex. From this perspective, working with modular formwork not only speeds up the process but also facilitates its execution.
The high standards required for finishes are integral to the quality of the project. Many Grand Paris Express stations will have exposed surfaces, which necessitates the use of high-quality steel formwork.

ENGINEERING FACTS

• - - Line 15 will be the longest metro line in France. Some stations are over 40 metres deep, equivalent to a 12-storey building underground, making it the deepest station in the country to date.
• - Tunnel boring machines with a diameter of over 10 metres were used, among the largest in Europe.
• - The steel formwork can be reused more than 200 times, reducing costs and time.
• - 7,000 m³ of concrete was used, delivered by 930 concrete lorries.

The Saint-Maur–Créteil section of Line 15 is a prime example of advanced underground engineering. Steel formwork for piers, particularly that supplied by specialist manufacturers such as Caldibe, has been essential in meeting the requirements for strength, precision and finish demanded by an infrastructure project of this scale.

Video: Assembly process

Find out more about the station’s development on its official website