Frame

Framing

The frame is an assembly of structural elements that make up the structure of a roof.
This framework is load-bearing and provided with bracing to guarantee stability. The frame can be made up of different pieces of wood, joists, concrete and metal profiles. Poor workmanship or technical non-conformities are not rare and they can affect the structure with the risk of rendering the structure unsuitable for its intended purpose.
An essential protection against bad weather, the roof is also an essential decorative element of your home and must be carried out in the rules of the art.

Different types of frames

Traditional timber frame

wood frame expertise

The so-called traditional frame consists of trusses, purlins and rafters. A farm is made by assembling several pieces of solid wood. The crossbowmen, the entry and the punch form the main network while the struts, the struts, the diagonals and the posts form the secondary network of a farm.

Components of a traditional wooden frame

expertise charpente bois

Industrial truss frame

farmhouse framework expertise

The trusses can be considered as rafters reinforced by triangulation. They are generally made with pieces of wood 36 mm thick (1'1 / 2) and assembled using metal connectors. This type of frame consists of transmitting the roof loads to the load-bearing walls via trusses placed approximately every 60 or 90 cm. Slenderness: the ratio between the height and the thickness of the truss being very large, this requires stabilizing the trusses by a subsystem of perpendicular bars called bracing and anti-buckling.

Components of a truss type frame

Glulam frames

wood frame expertise

This technique consists in reconstituting squarings from thin wooden slats, glued together.

Metal frame

The metal frame competes with the wooden frame in almost all areas. The construction of large span structures is simple. The vast majority of industrial buildings are made with metal frames, in particular for reasons of cost. Metal frames resist fire for a shorter period of time than those made of wood because the mechanical characteristics drop sharply when the temperature rises, while flammable and combustible wood loses its strength more gradually by loss of thickness.

Components of a metal frame

The right calculation

The disorders affecting the frames come from abnormal deformations that appear on a part of the frame, either
• elongation,
• shortening,
• buckling,
• flexion.
Each frame is the subject of a force study which is specific to it, several parameters are taken into account for the calculations.
The lengthening / shortening is due to the work of the part in tension / compression. That is to say when the force is exerted in the axis of the part.
When compressing a long part (example: post, crossbow), the part can flex. Then appear forces perpendicular to the axis of the part which amplify the phenomenon: it is buckling or buckling.
Bending is the appearance of a curvature (arrow) on a part, due to a force perpendicular to the axis of the part; for example the weight of the part on horizontal elements such as a joist, a purlin or a rafter.
Torsion is the deformation of a beam due to a moment whose direction coincides with the axis of the part.
A frame plan to scale determines the future shape and highlights every detail that will contribute to the strength and longevity of the structure. The slope calculation takes into account the weight of the roofing material, the intensity of the rains and the force of the winds. The possible stresses and strains help to strengthen the most sensitive areas. The frame is generally associated with certain easy-to-maintain elements such as gutters.


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