Long span wooden rafters enable the curved shape of Clamart sports centre
Images copyright Sergio Grazia

Clamart Sport Centre

Location France
Building Year 2016
Architect Gaëtan Le Penhuel Architects
Structural Design VS-A Group
Products Used Kerto LVL



The Clamart sports centre – embodies the urban landscape

The construction of a new sports complex for the town of Clamart is part of a vast High Quality Environment urban development project: the reconstruction of the Trivaux-Garenne campus.

This broad-reaching project features a school campus and a large sports centre. In line with the local authority's wishes, the architectural and urban approach in Clamart project is based on a desire to recreate links between two highly contrasted urban environments: residential zone of detached-houses and a sprawling district of tower blocks from 7 to 12 storeys high.

The sports complex contains a dōjō, a gym, a track and field area and a tennis court, all within one floor. The original and innovative use of Kerto® LVL (laminated veneer lumber) enabled the best possible freedom of curvature to fulfil the architectural vision of the complex. Metsä Wood’s delivery consisted of Kerto® LVL rafters for the building’s frame and roof structure covering an area of 5200m2.

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Architect Gaétan Morales

​Gaétan Morales is an architect at Gaëtan le Penhuel & Associés office since 2009. He graduated from the Ecole Nationale Supérieure d'Aarchitecture Paris-Malaquais. The design of the agency intends to reflect their common desire for an expressive architecture which affirms its uniqueness in his environment while keeping the quality of life and well-being of its occupants in mind at all times. All their projects are defined by this desire to create minimalist and pure lines, as they aim to build bright, quiet spaces. Morales was the Project Manager of the education and sports campus at Petit-Clamart.

Gontran Dufour

​Architect, partner and co-owner, VS-A - Structural Engineers
Lille, France 

After obtaining his Technological University Degree in Civil Engineering and Environmental Engineering in 1994, Gontran Dufour was awarded Architect D.P.L.G from the architecture school of Lille. Spending two years in various architecture agencies, he joined “van SANTEN et Associés” in 2001 where he developed the thermal research team of the office. In 2002, he created with Robert-Jan van SANTEN “van SANTEN & Associés” which became VS-A in 2010. He founded VS-A.HK together with Robert-Jan van SANTEN the  following year. He is also a frequent speaker on engineering techniques for building envelopes.

Antoine Roux – Engineer

​Antoine ROUX’s father and grandfather are carpenters. During holidays he used to work as a carpenter in the family business, and this is why he naturally followed the wood engineer studies himself.

In 2007 Roux graduated from ENSTIB, National School of Technology and Wood Industries, and then spent one more year doing Advanced Studies of Construction in Paris and completed a Master’s degree.

Since graduation, he joined the French-Swiss wood engineer firm Charpente Concept which is famous for references such as the “Palais de l’équlibre“ in CERN or the “Refuge du Goûter“ at 3’850m highness.

Today Antoine Roux is the director of Charpente Concept France and is active in promoting wood construction in France and Europe.

Design approach

Values guide Metsä Group's operations 

An authentic city of sports

The sports complex is shaped to follow the curves of the landscape. Designed to be an authentic city of sports, its rolling shape fits the intended use and the official dimensions of sports activity areas.
Different sports are brought together under one gigantic envelope. As if bent out of shape by its many uses, the building fits into the surroundings beautifully. 

The design work carried out by VS-A Structural Engineers was based on the definition of the architectural image and ensuring it matched the technical, structural and financial requirements of the project.
The technical solution connected the façade and roof together with a continuous structure. The solution required to optimise the shape of the structure while preserving the geometrical shape.

Talking Wood with architect Gaétan Morales

Why Gaëtan Le Penhuel Architects and VS-A engineers have been choosing Kerto® LVL (laminated veneer lumber) as the building material for the ambitious Clamart Sports Centre? Gaétan Morales, project manager-architect of the sports hall explains that Kerto® LVL enabled long spans and complex curves for which the sports centre is now famous for. Use of engineered wood frame also proved to be economical, structurally efficient and visually attractive. Watch the video below.

Long span wood frame

Values guide Metsä Group's operations 

Due to its complex geometry, the roof and framework design of Clamart sports complex involved challenging technical and aesthetic requirements. Major technical challenges raised  from the double curve in certain areas in the roof. Curved Kerto LVL forms the oval opening for the track and field area.
In Clamart project, Kerto LVL replaced glulam, which is generally used for building long curved beams. The use of Kerto LVL enabled greater architectural liberty, allowing wide spans, and optimising the wooden structure itself. The form of the beams enabled optimising the material as much as possible and limit waste due to precise cutting.

The dimensions of the complex are approximately 130 m x 40 m, with a maximum height of 10.35 m above the gym space.

More information

Load bearing structure

Complex Curved structure with Kerto LVL

The geometry of the wooden roof structure is extremely variable and complex. The metal façade transfers loads to the wooden frame, but do not contribute to the overall stability of the building. This was solved by a grillage frame structure made of Kerto LVL beams. The structure transfers the loads from roofing, while imposing the desired architectural form.

The main reason for choosing Kerto LVL as the building material is that it enables more freedom of curvature compared to glulam. Some of the members have very tight radius, which meant they could only be cut from 69 mm thick Kerto LVL Q-panels.

All the custom-made elements of the sports complex roof frame were designed one by one. The main challenge was to ensure that the elements supported the loads imposed by the shape of the roof.

Bracing with diagonals

Values guide Metsä Group's operations 

Adaptable Kerto LVL Q enables an aesthetic and accurate solution   

The roof consists of a 3 m x 3 m grid structure, which is formed from primary rafters connected to each other with secondary rafters. The primary rafters are hollow, made of two panels assembled together using internal flanges. The gluing of the flanges produced the desired strength and stiffness of the beams. This truss type structure transfers horizontal bracing loads to the vertical concrete frame of the building.

The bracing is completed with a metal diagonal between every rafter. Certain areas in the structure were reinforced in order to optimize the cross sections and reduce the material cost of the diagonals.

Steel-to-timber connections

High performance of Kerto LVL Q is good for connections

The cross-bonded Kerto LVL Q has a high connection strength that reduces the amount of required connectors and thus the size of steel plates. All of this allows significant savings for the carpenter both in terms of material and in time.

The excellent mechanical properties of Kerto LVL Q, notably the cross veneers, can improve the resistance of fasteners. The hollow cavity of the beams was used to hide most of the steel plates and for embedded metal fasteners.  and hide metal fasteners (brackets, bolts, dowels).

The engineering office Charpente Concept designed high-performance steel assemblies, suited to Kerto LVL which for the most part were invisible. Detailed design work enabled structural engineers at Poulingue, the appointed contractor for the frame and roof, to erect the huge spans easily to their place in the structure.

Arched box beams using Kerto-Q LVL panels
Arched box beams using Kerto-Q LVL panels

​The original and innovative use of Kerto-Q LVL offered the possibility of building long, curved box beams.

Kerto LVL can adapt to variable curvature
Curved columns using Kerto-Q LVL panels

Kerto® LVL can adapt to variable curvature. Some of the members have very tight radius, e.g. when columns transform to rafters. The members were cut from 69 mm thick Kerto-Q LVL panels.

Bracing wooden grillage frame structure with diagonal steel members
Bracing wooden grillage frame structure with diagonal steel members

​The diagonal bracing of steel members inserted in each “cell” of the roof structure  creates a continuous net, and thus transfer the horizontal forces between Kerto LVL box elements.

Connecting Kerto-Q LVL beams with high strength steel-to-timber connection
Connecting Kerto-Q LVL beams with high strength steel-to-timber connection

​The position of the joints has been selected optimizing the Kerto-Q panels and limiting the waste. Prefabricated dowel joints guaranteed smooth installation. Only a few bolts were installed on-site to facilitate operations.

Extensive 3D design

3d design for a complex curved timber frame 

Complex-technology project involving extensive 3D design work

The pre-design work done by VS-A set the basis for the structural design. In the execution phase, design office Charpente Concept adapted these principles to produce assembly details and construction drawings.

Gontran Dufour, associate director and joint managing partner of VS-A design office explains: "We discussed structural efficiency and produced analyses with our modelling and calculation systems to identify the most appropriate solution. In particular we worked extensively on the layout and all the design process was done in 3D, which was necessary due to the complex shape of the building. "

Antoine Roux from Charpente Concept explains: "This project is really exceptional, not just because of its size but also because of its shape. With its members’ curves, its dimensions and wide opening in the roof for the track and field area, very few pieces could be identical.”

He continues: "We had to size and design the whole building in 3D. It took 3,000 hours of design work to produce the 4,000 construction drawings. They can now be reused at different scales."
Cedric Roux, Manager of the Poulingue Design Office, concludes: "The 3D modelling process enabled us to export information of the elements to be used for manufacturing process. "

More information

Technical information


  • ​Surface area 130 m x 40 m = approx. 5,200 m² 
  • 18 m x 36 m oval opening above the track and field area. 
  • Over 500 m3 of Kerto LVL used 
  • 70,000 dowels and bolts 
  • 120 tonnes of steel 
  • 1000 steel assemblies, all different 
  • 4000 construction drawings / 3000 hours of work for Charpente Concept 
  • 12,000 hours of cutting and assembly of box beams 
  • Volume of Kerto LVL S used: 53 m3 / Volume of Kerto LVL Q used: 546 m3 
  • Height of largest rafter: 1200 mm 
  • Kerto LVL box beams with different curvature and assembled with continuity plates:
    • 562 secondary rafters with lengths varying from 2.8 m to 4.3 m 
    • 41 cross-members with a total length of 40 m 
    • 28 longitudinal columns with varying lengths between 5 and 8.5 m 
  • Maximum beam span: 30.4 m between supports



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