Course Project "Calculation and Design of Rafter Roof"

Contents

Contents

1. DESIGN INPUT

2. CALCULATION AND CONSTRUCTION OF ROOF FLOORING

2.1 Calculation of building floor

2.2. Design of Fabricated Flooring Board

3. CALCULATION OF RAFTER ELEMENTS OF CONSTRUCTION SYSTEM

3.1 Calculation of layered rafters

3.2. Run Calculation

3.3. Rack calculation

3.4. Calculation of buckling

3.5. Calculation of girder (fight)

3.6. Calculation of diagonal rafter leg

3.7. Calculation of rafter system components connections

3.8. Selection of mauerlat section and bed

4. RAFTERS COMMUNICATION SYSTEM

5. PROTECTION OF COATING OF WOODEN ELEMENTS OF RAFTER SYSTEM

6. LIST OF SOURCES USED

Protection of the coating of wooden elements of the rafter system

The wooden elements of the rafter system are subject to the following factors:

moisture exposure (exposure to rot);

exposure to fire;

defeat by wood-destroying insects.

Protection of wooden elements against rotting

Structural protection against rotting consists of a number of measures aimed at ensuring the drying of wood and maintaining its air-dry state in structures.

Constructive measures of protection provide for:

1). protection of wood from direct humidification by atmospheric sediments or production waters;

2). sufficient thermal insulation (on the cold side), and if necessary steam insulation (on the warm side) of enclosing structures to prevent their freezing and condensation humidification;

3). systematic drying of wood and aggregates by creating a drying temperature-moisture regime.

Wooden parts should be separated from masonry or massive metal parts of structures by waterproofing gaskets made of two layers of toll or pergamine with treatment on the side of masonry or metal with hot bitumen.

In addition to mandatory structural measures to protect wooden structures from rotting, wood antiseptics are also carried out.

Antiseptics are water-soluble and oily. Water-soluble antiseptics are aqueous solutions of sodium fluoride or silicon fluoride and other substances with a dye additive to distinguish the treated wood. They have no smell, harmless to people. Oily antiseptics are creosote, anthrocene and shale oils. They are very poisonous to mushrooms, but have a strong unpleasant smell and are harmful to human health. These antiseptics are not washed out with water.

Antiseptic treatment of elements of wooden structures and products should be carried out in production conditions with specialized equipment. If it is impossible to centrally supply construction with elements of wooden structures chemically protected from rotting, it is allowed to carry out antiseptic treatment of wood at the construction site by mechanized, and in some cases by manual, methods.

Methods of applying antiseptics:

1). Impregnation (surface impregnation with antiseptic) is carried out by completely immersing the wooden elements in the composition or by applying the substance with a pulverizer/conventional brush. For immersion, a special bath, trough or even a ditch is used, previously lined the container with polyethylene film. The immersion time of the material depends on the particular antiseptic. Usually, the manufacturer indicates a package of 3060 minutes for small and medium-sized wood. When immersing large farms, for example, for a roof made of natural tiles, the impregnation time is increased to four hours. After drying, all ends of wooden structures are treated during the day.

2). When the antiseptic is manually sprayed, sprayed or stained, the penetration efficiency of the composition deep into the wood is markedly reduced. Such a method requires a small amount of antiseptic composition.

Protection of wooden elements from fire

Fireproofing of wooden structures is carried out using the following substances:

1). Flame retardants. These chemical compositions serve to prevent wood from igniting. They are phosphate and swollen. Their feature is that during heating they form a film and inert gases that absorb excess heat and prevent oxygen from accessing the ignition site;

2). Fire retardant paints. These agents are applied to the wood in a sufficiently thin layer. In this case, a film of 1 mm is created, which, when heated to a high temperature, has the property of foaming and blocking oxygen access to the structure. Varnishes have the same characteristics;

3). Impregnations. Both organic components and combustible solvents can be mentioned in the composition of these agents. Therefore, you should be as careful as possible while working with them. Fire-retardant impregnation for some time can stop the spread of fire;

4). Combined substances. They can effectively protect the tree not only from fire, but also from pests (beetles, rodents and others).

Protection of wooden elements from wood-destroying insects

Wood of designs can collapse different types of insects, such as: bugs, rogokhvosta, butterflies, termites, also insects of a class of mollusks and Crustacea (sea shashen, sea crustacean, sea wood louse, etc.), etc.

The main pests are not the beetles themselves, but their larvae, which feed on wood, cut through the passages in it, turning it into a pipe (with the exception of the weevil, the beetles of which are themselves destroyers of wood).

Measures to combat woodblasting insects should be divided into preventive and extermination measures.

Preventive measures include:

1). careful selection of wood for wooden structures;

2). Prohibition of wood affected by wood insects for wooden structures;

3). impregnation and lubrication of structures with special liquids.

Fighter activities include:

1). impregnation of wood with toxic liquids for insects;

2). injecting poisonous liquids into flight holes (used at the initial stage of damage);

3). coating the surface of wood with poisonous compositions (the most affordable method);

4). spraying the surface of wood with poisonous compositions of hydropults (allows to treat wood in any position);

5). gas disinfection (fumigation) of wooden structures is not allowed, since gases are strong poisons for people and animals.

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