Deep Impact

SYSTRA continues to be deeply involved with the Paris Metro project - in more ways than one, says VINCENT DUGUAY, SYSTRA’s Urban Director

Opened in July 1900, the art nouveau-style Paris Metro system is one of the oldest and most iconic in the world. It is also one of the busiest, with its 302 stations handling more than four million passengers a day, and representing 20% of the overall traffic in the French capital.

SYSTRA has been a major player in the development of the 16-line (133-mile) Paris Metro, having designed the city’s first automated metro line (Line 14) in the 1990s.

The company is now also at the heart of the Grand Paris Express project, which will add four new lines to the network and further automate the system in order to add capacity for an additional two million passengers each day.

It was a real challenge, but our full BIM design helped us.

Vincent Duguay, SYSTRA’s Urban Director

The four new lines include a 47-mile circular line around Paris (Line 15), and three others to serve Charles de Gaulle Airport (Line 16) and other suburban areas (lines 17 and 18).

The project will open in stages between 2024-2030 and consist of 124 route-miles and 68 interconnected stations with 90% of it built underground. New fleets of fully automated rolling stock will provide a service at intervals of less than two minutes at peak times.

The Grand Paris Express was first announced by former President Nicolas Sarkozy in 2007 as part of the Grand Paris project to turn Greater Paris into a sustainable metropolitan area.

Vincent Duguay, SYSTRA’s Urban Director

He considered the size of the existing metro system to be too small compared to other global cities like London or New York and so wanted to add capacity. He also wanted to help create economic growth and new patterns of passenger flows by facilitating greater connectivity between suburbs, and by linking all three Paris airports for the first time.

What emerged was a project on a huge scale, costing 35 billion euros (£30.6bn), adding 200km (125 miles) of new track and with a 20-year programme of design and implementation.

The structure of the project means that Société du Grand Paris (SGP) is the overall project owner and contracting authority, while state-owned Régie Autonome des Transports Parisiens (RATP) will maintain the network.

In September 2013 SYSTRA was awarded a project management contract to provide technical expertise on the automatic train control systems and for rolling stock on Lines 15, 16 and 17.

SYSTRA was also awarded a contract by SGP to design infrastructure and supervise construction of the southern section of Line 15 from Noisy-Champs to Villejuif Louis Aragon which is due to open in 2025, and to design and project manage the construction of a new infrastructure maintenance centre at Vitry.

SYSTRA, in a joint venture with SETEC, was also awarded a project management assignment on the western section of Line 15, from Pont de Sèvres to Les Grésillons.

According to Duguay, this showcases the breadth of SYSTRA’s expertise, with more than 200 of the company’s engineers and other specialists involved in every phase of the line’s construction, from conducting pre-project studies in 2013 to breaking ground in 2017, and eventual commissioning trials and acceptance in 2024.

We are present at every stage of the project lifecycle on Line 15 South, doing all the work from initial designs to the end of commissioning. Our team consists of architects, designers, civil engineers, project managers and contract managers. We can offer clients a large number of functions for projects which, like in Britain, use Building Information Modelling [BIM] from conception.

Vincent Duguay, SYSTRA’s Urban Director

The southern section of Line 15 is costing 7.8 billion euros to construct and has already proven particularly complex with 21km of tunnels and eight underground stations being built as deep as 50 metres below some of the most densely populated parts of Paris.

Duguay says that a full BIM design was employed to offer SGP a better view of the station concepts created by SYSTRA, to improve cost control and to enhance the quality of the relationships between architects, construction engineers and ultimately the operator and maintainer.

He explains: "This new metro line will be one of the deepest in the world because Paris is very densely urbanised and there are lots of utilities buried in the ground. One of the key constraints has been how to design the stations, so we’ve chosen to install large concrete modular walls for the station boxes. They can be up to 1.8 metres thick and 75 metres deep, which is pretty massive for this type of project - it can take up to 17 hours to pour that much concrete.

“We’ve also had to freeze the surrounding area to tackle the problem of groundwater. This has meant freezing areas up to 50 metres deep and 30 metres wide. It was a real challenge, but our full BIM design helped us and we were able to bring in equipment used in the petroleum industry to harmonise the ground conditions.”

A second key constraint to the construction sequence has been the need to limit disruption to existing transport infrastructure. When the western section of Line 15 is complete it will be intersected by Metro lines 1 and 13, Lines 14, 16 and 17 of the Grand Paris Express, the RER Regional Express Lines A and E, and Tramline T2. Seven of the nine stations will provide interchanges, with lines operated by either the French railway operator SNCF or local transport operator RATP.

Stations and infrastructure have also had to be cleverly designed so that future changes in demand can be easily accommodated and so that new metro systems and technology can be seamlessly integrated as they emerge.

"All of the stations on Line 15 have been designed as interchanges, so passengers can change very easily between lines. The precautions we take during construction are, therefore, very important, so that existing lines are not damaged or disrupted in any way."

"We also have to ensure that capacity in the stations is suitable for future development because the client in Paris wants to make sure that they not only have a modern metro but one that is fit for the future."

"It can be difficult to plan for future solutions, technical developments and new maintenance regimes when assets like walls and ceilings are quite difficult to modify at a later date, but at SYSTRA we are committed to providing ever more resilient and innovative solutions."