The structural work
The structural work is the implementation of elements contributing to the strength and stability of a building. They resume the permanent efforts of construction and temporary efforts such as wind, rain and snow. It includes essential phases such as earthworks, reinforcement and formwork, masonry and the laying of structural elements. It integrates or provides for the implementation of watertight barriers with the exterior and the maintenance of the second work (insulation, frame, facade, roof, equipment, etc.)
After the location of the “chairs” by the surveyor, the excavator evacuates, displaces or levels the lands and rocks of the ground in order to prepare the base of the building. This phase prepared upstream by a precise soil quality survey is vital for the overall stability of the future building.
When the “good soil” is reached, the excavator then creates the trenches for the runners (ventilated empty) and / or flattens the base of the slab (cellar). For unstable soils, the operation requires drilling.
At the end of the construction site, the digger again intervenes to backfill the land and cleanly clear the area.
Slab, reinforcement and formwork
At the end of the earthwork, the bed of the slab is paved with draining pebbles then covered with a leveling sand layer. A last impermeable barrier, the Visqueen, ensures watertightness and a good drying of the raft.
After fabrication of the formwork, the concrete is then poured into place, armed with steel bars previously sized by an engineer. A perimeter drain is placed or, depending on the level of the water table, a sealed casing may be considered.
Masonry is an ancestral implementation of the art of building. The main categories of materials used are mineral or vegetable, mainly brick, stone and concrete block.
Binders, such as cement and plaster, and mortars made of a mixture of binder, aggregate and water such as cement mortar are distinguished. Concrete has evolved from rammed earth to cement concrete. It is today the most widespread material in the world.
In constant evolution, the profession is now leaning towards cellular concrete blocks, lighter to handle, and masonry glue, while Asia is already focusing on robotization and large-scale 3D printing.
To ensure the stability of the building, the architect and the engineer take into account the soil and the permanent and temporary efforts related to the weight of the building, its occupation and natural hazards. The beams and columns make it possible to free the space and to vary the arrangements while avoiding the cumbersome superposition of bearing walls.
In heavy construction concrete structural elements are either cast in place when access to handling is impossible, or delivered prefabricated with a possible prestressing. Depending on the configuration, the use of steel, thinner and lighter, is the most common alternative.
In the case of a light construction, it is the wood that will ensure the structural role.