IFAPME and FOREM need a building allowing a large number of students to come and follow their training. The project consists of classrooms and training area R+2 divided into 4 wings: 3 separate wings with their distinct roles and a common circulation wing. Against this set, we find 3 large workshops and a marshallery.
We articulated our structural design process around a central idea: We wanted to inscribe the building in its time by making the project a model of low carbon design. In this reflection, we had to take into account the architectural issues and more broadly the respect of the program defined by IFAPME and FOREM. The building will be dedicated to education and is therefore the perfect opportunity to show by example that it is possible to build differently. Nowadays, we have to take into account the environmental impacts while being financially competitive. Using wood as the main material is obvious in this context, even if its use is still far from being widespread enough. This material, which is at the heart of our work, has a much lower carbon impact than traditional materials, but it also allows to store the CO2 captured from the air during the growth of the tree. We wanted to go even further than “just” using timber by limiting the use of glue in the wood and favoring its use in a less transformed form.
For this reason, we chose to build the floors with semi-massive slabs made up of a large number of small elements and assembled mechanically without glue. In addition to being very simple to produce, these elements optimize the quantity of wood used since all the fibers work in the direction of the span and participate fully in the stiffness of the whole.
The floors above the central circulation corridors will be made of CLT in order to facilitate the passage of techniques.
These floors are supported by beams made of glued laminated timber or baubuche (LVL of beech allowing a resistance up to 3x superior to traditional wood). The beams are supported by columns, also made of glulam. The entire wooden structure is capable of withstanding at least a 1-hour fire. Indeed, wood, unlike steel for example, has a very predictable and regular behavior when it is ignited. This allows us to dimension the sections accordingly so that the building’s load-bearing elements continue to play their role during a fire and allow users to evacuate in safety.
The load-bearing and wind-bracing walls are made of wood frames.
In the workshops, large wood and steel trusses cover the large spans for a minimal footprint on the ground.
The entire structure rests on a reinforced concrete slab that allows for excellent load distribution on the building’s surface.