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Individual two-storey residential building with wooden frame - AS

  • Added: 29.07.2014
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Coursework on wooden structures. Two-story individual residential building with wooden frame. Drawings, Explanatory Note

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Contents

1 GRATING CALCULATION

1.1 Initial data

1.2 Load collection

1.3 Determination of forces

1.4 Geometric characteristics of the cross-section of the screen

1.5 Strength calculation (1 GPS) for the second load combination

1.6 Stiffness calculation (2 GPS) for the first load combination

2 CALCULATION OF RAFTER SYSTEM COMPONENTS

2.1 Rafter system design

2.1.1 Geometric diagram

2.1.2 Load collection

2.1.3 Determination of forces in rafters

2.1.4 Geometric characteristics of rafter leg section

2.1.5 Rafter leg strength calculation (1 GPS)

2.1.6 Calculation of rafter leg for stiffness (2 GPS)

2.1.7 Calculation of brace

2.1.8 Calculation of tightening connection with rafter leg

2.2 Design of the adjustment system

2.2.1 Calculation of Run with Chocks

2.2.2 Adjustment system rack calculation

3 CALCULATION OF STRUCTURES OF INTERMEDIATE FLOOR

3.1 Initial data

3.2 Calculation of all-wood beam

3.2.1 Load collection

3.2.2 Determination of beam forces

3.2.3 Cross section selection

3.2.4 Geometric characteristics of the section

3.2.5 Strength calculation (1 GPS)

3.2.6 Calculation for stiffness (2 GPS)

3.2.7 Stability calculation (2 GPS)

3.3 Calculation of gluing beam

3.3.1 Load collection

3.3.2 Determination of beam forces

3.3.3 Selection of beam section

3.3.4 Geometric characteristics of the section

3.3.5 Check of upper belt for compression stability (1 GPS)

3.3.6 Check of lower belt for tensile strength (1 GPS)

3.3.7 Check of plywood wall for tensile strength (1 GPS)

3.3.8 Check of plywood wall strength at shear (1 GPS)

3.3.9 Checking strength of adhesive joints in support section

3.3.10 Wall stability check (1 GPS)

3.3.11 Calculation for stiffness (2 GPS)

3.3.12 Stability calculation

3.4 Calculation of floor board

3.4.1 Load collection

3.4.2 Determination of forces in floor boards

3.4.3 Geometric characteristics of the section

3.4.4 Strength calculation (1 GPS) for the second load combination

3.4.5 Stiffness calculation (2 GPS) for the first load combination

4 BUILDING EXTERIOR WALL DESIGN OPTIONS

5 CENTRAL COMPRESSED RACK CALCULATION

5.1 Initial data

5.2 Load collection

5.3. Whole tree rack calculation

5.3.1. Calculating Cross Section Dimensions

5.3.1. Check of strength of accepted section

5.4. Calculation of composite rack

5.4.1. Checking Stresses in Composite Corner Post

6 MEASURES FOR PROTECTION DURING HARVESTING, TRANSPORTATION, STORAGE OF LUMBER

6.1 Procurement

6.2 Transportation

6.3 Storage

6.4 Protective Wood Treatment

6.4.1 Rot Protection

6.4.2 Fire and combustion protection

6.4.4 Protection against biological damage

6.5 Operation of wooden structures

7 INSTRUCTIONS FOR ASSEMBLY AND INSTALLATION OF STRUCTURES OF WOODEN FRAME HOUSE

CONCLUSION

LIST OF SOURCES USED

Measures for protection during harvesting, transportation, storage of lumber.

6.1 Procurement

Sawn timber is obtained from softwood, hard and soft hardwood as a result of longitudinal division of sawn log (GOST 9463 and GOST 9462) into parts and longitudinal and transverse cutting of the obtained parts.

Lumber is manufactured in accordance with the requirements: GOST 8486, GOST 26002, GOST 9302, GOST 2695, GOST 968, GOST 24454.

Logs intended for sawing must be stored in conditions that protect timber from decay. The main method consists in drying the logs in a shorter period of time (in summer time) to a humidity of about 20%, in which mushroom lesions do not develop. Logs in this method for protection against soil moisture are stored on liners, having previously removed bark.

Drying of wood.

Wood drying is the technological stage of preparation of raw materials for further processing, its strength depends on it, the absence of cracks on the tree, the purity of the nozzle, the quality of gluing and varnishing, milling and grinding.

Process Tasks:

Making wood biologically resistant;

Increased wood strength (dry wood can better withstand mechanical stress);

Improvement of wood quality.

Atmospheric drying is carried out in open air. Boards are laid with clearances (on gaskets) providing ventilation of stack. To prevent atmospheric and ground moisture, the stack is laid on liners and a canopy is arranged on top, and for uniform drying of all layers of the stack boards, it is periodically shifted. The duration of drying in stacks depends on the climatic conditions of the terrain, the season, the thickness of the boards and the required final moisture of the lumber. For example, for boards 30-50 mm thick in summer in the Moscow region, the drying duration is 10-16 days when dried to a final humidity of 30% and 20-40 days to a final humidity of 20%. Due to such a large difference in drying time, depending on the final humidity of the boards, it is recommended to dry the lumber to a humidity of 30%, followed by drying in the chambers to the required humidity of 8-12%.

Chamber drying is carried out in drying chambers, inside which increased temperature and intensive circulation of heated air or superheated steam are maintained. The removal of moisture from the wood begins with the outer layers, so the humidity remains uneven in the thickness of the lumber until the very end of the drying process. With excessive moisture removal from the outer layers and a large moisture drop across the layers in the boards, cracks can occur, so the process is carried out in such a way as to first warm up the moisture in the wood, limiting its removal from the surface of the boards. This is achieved by introducing wet heated air at a temperature of 50 ± 5 ° C into the chamber at the first stage. Then, as the wood is warmed and moisture is reduced, the air temperature is increased and the air humidity is lowered. Before machining, the boards discharged from the chamber must be stored for three days in a room with an air temperature of 16-22 ° C and an air humidity of 60-70% (conditioned) in order to equalize the humidity along the section.

6.2 Transportation

Sawing raw materials may be transported by rafting, rail or road. Structures made of wood and plastics shall be transported taking into account their low hardness and slight damage. When transporting elements of bearing and enclosing structures made of wood and plastics, measures should be taken to protect them from humidification, accidental impacts and other adverse effects. It is particularly to be feared that forces may be applied which may cause the wood to break across the fibers or to tear off the adhesive seam. Elements can be picked up during lifting only in places marked on the product in accordance with working drawings.

To protect wood and lumber from rot, cracking and damage by mushrooms during transportation, treatment with their corresponding protective compositions is used.

6.3 Storage

Storage of lumber (GOST 3808.180 * and GOST 731980 *) shall ensure protection of wood from damage by fungi and insects, from cracking and warping .

For lumber storage, two types of warehouses are arranged: open and closed.

Storage of lumber in open warehouses should take place in dry, well-ventilated areas, canopies are located along the direction of the prevailing winds. For open warehouses, places with sandy soil and with low groundwater standing are used. Open canopies are used for storage of wood for not more than one summer season and for storage of wood during testing of its physical and mechanical properties. Canopy capacity 150 - 180 m3 .

Closed canopies are equipped with disassembling walls, exhaust lights and serve for long-term storage of wood, checked by physical and mechanical properties and selected in size. The canopy capacity is about 300 m3 (20 platforms), length 30-35 m, width 12-16 m, height 6 m. Closed canopies are located across the direction of the dominant winds.

On the sides of the canopy, the bases are arranged under the stacks, leaving a passage 3 m wide in the middle. The ground under the canopy should be paved, concreted or covered with asphalt.

The side walls of the canopy should reliably protect the lumber from precipitation and sun during summer and winter and at the same time ensure sufficient ventilation of the canopy and good air drying.

The bases of the canopies of both types and the bases under the stacks should stand on stone pillars. Wooden parts of the canopy and the base under the stacks should be made of healthy forest and treated with antiseptics (creosote). The roof must be iron or double thick in solid formwork. Soil under an open canopy must be filled with sand or ash.

6.4 Protective Wood Treatment

6.4.1 Rot Protection

Rot is the process of wood destruction caused by the vital activity of fungi. Mushrooms are divided into woodblowers (not causing a decrease in the mechanical strength of wood) and woodblowers: molds, forest, warehouse and house mushrooms, of which only molds practically do not reduce the mechanical strength of wood.

The destruction of lignin produced by forest and some types of storage mushrooms is called corrosive rot, the destruction of the main skeleton of wood (cellulose) by house and some storage mushrooms - destructive rot. With destructive rot, not only longitudinal, but also transverse cracks occur.

The development of the rotting process begins in wood if its humidity is not lower than 18... 20% at air temperature + 2...... 35 ° С. Under water, rotting does not occur due to lack of air.

In terms of resistance to rotting, the species and zones of wood are divided into four classes:

I-resistant (pine, ash, core of oak and larch);

II-medium-resistant (spruce, fir, peripheral part of cedar, larch disease, central zone of beech);

III-low-resistance (birch disease, beech, hornbeam, oak and maple, elm core);

IV-unstable (alder, aspen, linden disease, central zone of birch).

Structural measures to protect wood from rotting include the design and manufacture of such a wooden structure that could dry out during operation, even if it wetted; insulation of wood with various waterproofing materials; protection of wooden structures and articles from atmospheric precipitation; prevention of moisture condensation, removal of water from wooden structures or products; arrangement of ventilation channels; insulation of the underground; arrangement of casts and drains near external window bindings.

Chemical protection of wood against rotting

Antiseptics. These are mushroom-poisonous substances that must maintain a given toxicity for a given period of time, easily penetrate the wood, not corrode with metals and not reduce the strength of wooden structures.

Antisepting is not a permanent measure of protection of wood, but protects wood from rotting only for a certain time (2,., 3 months). But in combination with structural protection measures, it allows you to significantly extend the service life of wooden building structures and products. Antisepting is especially necessary if the wooden structures are to be operated under heavy wet conditions .

There are the following types of antiseptics: antiseptics in aqueous solution, oily antiseptics, organic antiseptics, antiseptic pastes, powder antiseptics (powder).

Methods of antisepting wooden parts and structures. Lumber, parts to be impregnated with antiseptics must be cut to remove the lube, cleaned of dirt, sorted by rocks and humidity. In order to increase the penetration depth of the antiseptic during the treatment of hard-to-drink wood (pine core, spruce, fir, larch), it should be pre-heated to a depth of at least 15 mm. The stringent surface is soaked worse than the sawn surface. The best antiseptic treatment is achieved no later than 24 hours after the lumber leaves the sawmill.

Antiseptic methods are used: diffuse powder antiseptic treatment, antiseptic paste treatment; impregnation (based on capillary suction) - impregnation in baths, surface impregnation with aqueous and oil antiseptics; creation of overpressure - impregnation by displacement of wood juice, impregnation in autoclaves; dry (powder) antisepting (mixture of antiseptic with filler is applied to wood with moisture content of 60% or more).

6.4.2 Fire and combustion protection

Wood ignites and burns as a result of its heating to a temperature at which its thermal decomposition begins to form combustible gases containing carbon. Thus, wood as an organic material is combusted.

Wood fire and the spread of fire are impossible without certain favorable conditions. Prolonged heating at a temperature of 150 ° C or fast at a higher temperature can lead to ignition of wood. Ambient air enriches the oxygen combustion process and promotes flame propagation. Elements of structures consisting of separate boards with gaps between them are heated faster to a dangerous limit than monolithic ones, have large surfaces of contact with air and adjacent surfaces mutually heated by radiant heating. As a result, their fire resistance limit is significantly lower than that of monolithic elements .

The purpose of fire protection is to increase the fire resistance of wooden structures so that they resist fire longer and do not create or spread an open flame during combustion. This is achieved by measures of structural and chemical protection of wooden structures from fire.

The structural protection of wood against fire consists in eliminating the conditions favorable for the occurrence and spread of fire. In structures of industrial buildings with hot processes, the use of wood is unacceptable. Wooden structures shall be separated from furnaces and heating devices by sufficient distances or fire resistant materials. To prevent the spread of fire, wooden structures should be divided into parts by fire barriers and fire-resistant areas. Wooden enclosing structures shall not have communicating cavities with the air rod, through which flames that are not available for extinguishing can spread.

Chemical protection against fire is provided in cases where a higher degree of fire resistance is required from enclosing wooden structures, for example in premises where flammable materials are located. It consists in fire-fighting impregnations and painting. Flame retardants are used for fire-retardant impregnation of wood. These substances introduced into the wood melt or decompose under dangerous heating, covering it with fire-retardant films or gas shells preventing access of oxygen to the wood, which at the same time can only slowly decompose and melt, without creating an open flame and without spreading fire. Impregnation of wood is carried out with simultaneous impregnation with antiseptics. Protective paints based on liquid glass, superphosphate and other substances are applied to the surface of the wood. When heated during a fire, the films swell from the emitted gases and create an air layer that temporarily prevents fire.

6.4.4 Protection against biological damage

Biological damage - damage by insects (wormhole), parasitic plants and birds. A wormhole is a collection of moves and holes made in wood by insects and their larvae.

Derevorazrushayushchy insects destroy various structures of houses: overlappings, floors, parquet, partitions, etc. and also furniture, cold constructions.

Precautionary measures to combat woodblasting insects are:

Timely uprooting of stumps in forest areas;

Cleaning of burnt trees and burrells;

Export of harvested wood from the forest before the beginning of the summer period of beetles;

Wet (underwater) storage of uncoated logs in summer;

Scrubbing of wood sludge;

Timely (before thaw) removal of bark from logs subject to dry storage;

Destruction of affected wood.

Methods for protecting wood from wood-destroying insects are antisepting and special chemical treatment of wood (in case the wood is already affected). A good way to protect wood from wormhole is oil painting and varnishing, provided that the protective layer is completely continuous. In order to detect insects in a timely manner and to take effective measures, all wooden parts of buildings and structures must be inspected regularly, especially for structural structures. Timber with signs of contamination by woodblasting insects cannot be used in construction.

Fighter methods for combating woodpecker beetles include: heating in chambers to a temperature of 80 ° C and above (suitable for lumber, furniture); smoking in special chambers with poisonous gases (chloropicrin, etc.); impregnation of wood by injecting insecticides with syringes into flight holes; surface treatment for 2... 3 times with paintbrushes during the flight of beetles.

6.5 Operation of wooden structures

Wooden structures must work reliably during all their normal operation periods established by SNiPom: for capital structures - 50 years, agricultural buildings - 20 and for temporary buildings - 10 years. Well-fabricated and normally operated wooden structures can work reliably much longer than these times. Normal operating conditions are such that wooden structures are not damaged, the loads acting on them do not exceed their carrying capacity, and the temperature and humidity do not exceed the permissible values. When these conditions are violated, wooden structures can prematurely lose their bearing capacity and rigidity.

Thorough inspection of wooden structures should be carried out at the time of their commissioning and in the future be repeated at least twice a year, as a rule, in autumn and spring.

During inspection and inspection of wooden structures, all defects that occurred during manufacture, transportation, storage and installation and in case of violation of normal operation mode of structures shall be installed and recorded in the list of defects. During the inspection the main attention shall be paid to the main factors affecting the bearing capacity of the structure.

Deviation of the dimensions of the elements from the design, the presence of serious damage and unacceptable wood defects can lead to a mismatch of the load-bearing capacity of the structure with the loads acting on them.

If the specified defects are detected, the design verification calculation is made taking into account these defects. If it is revealed that the structures have unacceptable load bearing capacity, the values ​ ​ of the loads acting on them should be strictly limited or the structures strengthened in accordance with the instructions.

During operation of the high humidity wood structure, longitudinal dry cracks may occur in the elements during drying. In most cases, they slightly reduce the bearing capacity of the elements. If they reach an undesirable value, they are eliminated by gluing wedge-shaped inserts of an appropriate size on a waterproof glue.

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