Frame

The Wood of frame

The wood turpentines used in carpentry are the Chêne, the Châtaignier, the spruce, the pine, the Sapin the Peuplier trembles, the Mélèze and the Orme. The trees with the foliage Caduc must be shot down in winter to be out-sap. The Résineux can be crossed all the year. When the branches of the tree are cut, one obtains a clear Grume, size of the tree. This operation is called the Façonnage. The bark is then cut in its length in various parts called Bille S.

The balls are then output in a Scierie. According to the diameter of the ball and quality of its wood, wood will be used either for the carpentry, or for the Menuiserie, or for the cabinet work. The but log is the part of the bark going of the foot of the tree to the first branches.

Constitution of a frame

Roof truss

It consists of firm S, breakdown S and Chevron S (all these parts are out of wood or steel).

the farm constitutes the essential component of a roof of a Toiture. It is it which transmits the general weight of the cover to the vertical carriers (walls, posts…). It can rest on posts, on the load-bearing walls, sometimes on the breakdown sand pit.

the breakdowns are the connection elements between the farms. There exist 3 types of breakdowns: the sand pit, posed on the walls; the breakdowns purlins positioned in medium of side of roof and the ridge purlin, in top of roof called the ridge sheathing. It is by them which the loads of the rafters forward towards the farms. Distance between centres: 2 to 3 m, section of 6,3 × 17,5 to 10 × 25 cm.

a rafter distributes the weight of the roof on the breakdowns. It is laid out in the direction of the slope with a distance between centres (distance from one axis to the other) from 50 to 60 cm maximum, according to the type of cover. The traditional sections are of 11 X 8 cm, 9 X 6 cm and 5 X 4,5 cm (height X width).

The roofs are protected from the deformations due to various constraints, permanent or occasional, by various parts of " contreventement". Thus, the farm can be more or less complicated by parts called in the wooden carpentries of the " aiguilles" (for example of the " poinçons"), " contrefiches" , " legs of forces" , " blochets" , etc In the longitudinal direction, the farms are " contreventées" by various parts which obliquely connect them between them or which connect them to the breakdowns, or still connect the breakdowns between them. The precision of the assemblies plays a determining role in the frame, the demanding traditional practices are replaced today by various techniques.

This is the case in France of the contemporary wooden carpentry with traditional tendency. Historically, the wood frames were made up in certain areas of " rafters forming ferme" , in other words small farms made up with each pair of rafters, not asking for parts of too important section. In this case, pairs of these " rafters-arbalétriers" can be more spaced. This provision, which practically ceased in France at the end of the Middle Ages, perduré until the twentieth century in Central Europe, and leads to the contemporary frame of " fermettes" , made up on the same principle but with parts of lower thickness and industrial assemblies.

A frame is designed most of the time on CAD and some times on paper. The drawing of the frame generally realized to the 1/10e is called diagram. It makes it possible to find the assemblies necessary as well as the dimensions of the parts to be realized.

Other types of frame

It is necessary to quote the frame with sides of wood which is a vertical specific structure, the frame of the floors, as well as the massive walls made up either of parts of stacking, or (in some Scandinavian countries) of juxtaposed vertical parts. In Central Europe, there exist massive wood floors, facts of juxtaposed horizontal parts.

The manners of building often differ from one country to another, sometimes from one area to another. In France, the terminology can differ from one area to another, which compromises the validity of certain entries of dictionary, which always keep a value of reference.

The Companions of the Tour de France devoted several volumes of their Encyclopédie of the Trades to the carpentry, which constitutes an exceptional source, but she testifies to the difficulty in indicating a " term; français" of frame, when there are some so much (to compare the vocabulary and the articles of this work). Older, the practical Dictionary of joinery, cabinet work, frame of J. - Justin Storck, published by layers until the beginning of the twentieth century and now republished, gives also invaluable indications on the traditional methods and provides a point of view on the terminology.

Out of the works of the building conceived to be most durable, it is necessary to quote those which intervene in a provisional way, even if they persist. The frame of building site includes/understands the clotheshangers and formwork, propings and scaffolding.

To completely leave the building, of the bridges, stoppings and other works of art can be built out of wood. The carpentry of navy, finally, constitutes a distinct discipline.

The frame is, by definition, a specific carrying framework, in opposition to the linear structure which constitutes a continuous wall. It can be out of metal wood or, but also out of reinforced concrete. In this last case, and although that corresponds to the definition of a frame, it is more usual of speaking about a " concrete armé" framework;.

The metal frame competes with the carpentry wooden in almost all the fields. The differences in behavior between two materials decide choice in general, as well as the prices.

Industrial frame

The sluice-gate trusses can be regarded as rafters reinforced by Triangulation. They are generally manufactured with pieces of wood in 36 mm thickness (1 ' 1/2) and assembled with assistance of metal connectors. This type of frame consists in transmitting the loads of roof to the load-bearing walls via farms laid out all the 60 or approximately 90 cm. The twinge: relationship between the height and the thickness of the farm being very large, that forces to stabilize the farms by a perpendicular subsystem of bars called Contreventement and anti Flambage.

The installation of an industrialized frame requires very little time. The advantages of this type of frame are: low costs and very a resistance positive ratio/lightness. These structures are also used used apart from the roof for, for example concrete the formwork, the scaffolding as well as false works of support of industrial projects. The profiles and forms are almost infinite, which makes it possible to obtain very varied roofs.

For the construction of dwelling, the ranges are included/understood between 8 and 15m. Ranges of 25 m can-being reached for the agricultural buildings or industrialists by using more important wood sections, that implies specific techniques of assembly.

Frames in lamellate-stuck

This technique consists in reconstituting squarings starting from wood plate of weak section, stuck between them.

The scope of application includes/understands them:

buildings of public use,
buildings of great range,
corrosive conditions (chemical, dyer, cereal storage, swimming pools…)

Because of a rather weak, and constant combustion (~2cm/½ hour), the timber structures lamellate-stuck have a great fire resistance. Lastly, it is with knowing that the arcs of these frames are worked out by joining with contrefil and back-plate of pieces of wood, in order to distribute the work of lamellate-stuck on all the part.

The study of the forces on a frame

One can define 4 efforts being able to be exerted on a piece of wood of a frame: the inflection, buckling, traction and compression.

The inflection is exerted on pieces of wood generally horizontal such joisting, the breakdowns but also on the rafters. Definition: it is the passage of the rectilinear state to the state of curve what gives rise to an arrow on a horizontal part.

Buckling is an inflection due to the compression of a long part (ex: post, principal rafter).

Traction tends towards a lengthening of the parts whereas compression tends towards one racourcissement.

It is especially necessary to note in the design of a frame and in particular of a farm which the punch should support no effort.