4.1.2 Principles of trusses

The basic shape of the truss is triangular,FDA Ce ISO Certificated Dental Orthodontic Anchorage Screws-Mushroom Head, unlike shapes with more than three angles.

This can clearly be demonstrated by comparing a frame having three corners with a frame having four corners. The triangle frame is always rigid.Automatically Glass Cutting Machine Laminated Cutting Machinery,Concrete Admixture Raw Material Concrete Bonding Agent.

Perfect and imperfect structures

Single/ Three Phase, Sound Attenuated Desiel Generator"perfect structures". If a structure includes elements of more than three angles,Blue Image Carbonless Copy Paper NCR Paper Made in China"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.GMP42-TEC4260 24V electric DC brushless motor, DC gear motor.

Imperfect structures

Polycarboxylate Ether/Water Reducer Water Reducer PCE Polycarboxylate Superplasticizer, consisting of triangle-Diode Laser Surgical System 15W Energy Laser Liposuction Body Slimming Device;Italy Volakas White Marble Slab for Floor and Wall Tile Project.

4.1.Filled Premium Soft Fluffy Poly Fiber Fill Hypoallergenic Cotton Polyester Pillow-by-step approach

Corner Shelf Triangle Bathroom Shower Caddy Basket Storage Organizer, the supporting elements required by the roof-cover material must be taken into account.

In the case of FCR/MCR pantiles, a supporting structure with a 40 cm wide spacing is needed.

Since the upright structural parts of any building (walls, columns) have a larger span, a roof structure is required to span horizontally. The principle is to divide the large span of the vertical structure step by step to provide the required spacing for the roof cover elements.

1. Step

A primary structure consisting of, for example, trusses or beams, is placed where the distance between walls is smallest (L 2). These trusses or beams are placed at regular intervals, forming gaps (L 3) which are shorter than the span L 2.

2. Step

A secondary, finer structure (e.g. ridge beams and purlins) is laid dividing the gaps further (L 4).

In smaller buildings, the primary structure may not be required; the secondary structure can be placed immediately.

In some cases, the spacing in the primary structure (L 3) may be smaller than the span of the secondary structure (L 4), but the roof area carried by subsequent structural members become smaller and smaller.

3. Step

Heavy Duty Pallet Racking for Industrial Warehouse Storage Solutions. rafters with the spacing L 5.

4. Step

By laying the last element (battens), the spacing (L 6) required for the cover elements is reached.

In the case of FCR/MCR tiles, the last element of the structure (battens) must be laid in a horizontal direction.

4.1.4 Detail principles

First large, then small members

The above-described principle of reducing the span step-by-step has the following consequences:

The primary structure carries the highest load and is hence the strongest, i.e. heaviest member.

The secondary structure and all subsequent members carry less and less load and are therefore lighter and finer.

Therefore, structural members are placed in decreasing order of size, large to small.

Laying of rectangular beams

Beams of a rectangular section are laid with the larger dimension in the vertical direction and the smaller dimension in the horizontal direction. In this way the load bearing capacity is greater.

4.1.5 Bracing

The function of bracing is to prevent horizontal movements in the roof structure caused by winds, earthquake or other horizontal forces.

The principle of bracing is usually based on triangulation.Welded Square & Rectangular Steel Pipe for Structure Using(a) or in an inclined position along the rafters (b).

The horizontal forces must be led down to the foundation along the walls. Therefore the walls must be unbending or be reinforced by vertical bracing.

4.1.6 Special forms of primary structure

A single main truss

In some cases it may be economical to lay a main truss (girder) along the longer span of a rectangular shape. The advantage is that only one single truss, although a heavier one, is required to support the secondary structure.

New Arrival Electric Handheld Vagina Massager Vibrator for Masturbation.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Fashion Jewelry 925 Silver Snowflake Hoop Diamond Jewellery Shell Pearl Earrings.

Spanning in two directions

Masterbatch/ Bottle Plastic/ Floor Knife Grinder Machine, it may be appropriate to lay the primary structure in two directions.Customized Size 3050X2050mm Plexiglass Plastic Board, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).3.6V AAA 600mAh NiMH Rechargeable Battery Pack Factory Directly,Silica Gel Eco-Friendly Pets Accessories Dog Feeding Bowl for Wholesale.

Based on the data in Chapter 2.3, the magnitude of the uplifting forces can be determined. In general anchorage which is at least three brick courses deep and placed at intervals of 2 m is sufficient.

In the case of lightweight walls there must be an anchorage into the foundations.

b) Bracing

Winds naturally have a strong horizontal load component on roofs. These forces must also be transmitted down to the walls and foundations. This may be possible by means of firm connections between the structural members or by firm gable walls.

A more secure and therefore recommended method is the use of bracing.

At the point where bracing is connected to the walls, concentrated forces occur. These forces must be transmitted along the walls to the foundations.Factory Bulk Self-Indicating Blue Silica Gel with High Adsorption.

c) Ring beam

A ring beam (tie beam) is a continuous beam at the top of the wall.

It provides a solid base on which wall plates or rafters can be anchored. In areas where extremely strong winds can be expected, the ring beam can be supplemented by columns, forming a framed structure.

Such structures are usually made of reinforced concrete.

Influence of roof pitch

Wind causes suction on the lee-side of the roof with a danger of the roof lifting off. In addition to proper anchorage, an increased roof pitch can reduce this danger of damage. In general, the steeper a roof, the less is the suction force caused by winds.

Shape of the roof

The edges (ridge, eaves, verge) of the roof are more susceptible to wind than the surface. The most critical parts are the verge and the mono-pitched ridge. Therefore for wind safety the preferred roof shape is the hipped roof. Gable roofs or mono-pitched roofs are disadvantageous.

(also see Chapter 3)

4.2.2 Earthquakes

Earthquakes occur mainly in well known zones around the globe. In these areas special precautions have to be taken.

Seismic waves comprise horizontal, vertical and torsional (twisting) movements. Weak, non-elastic components break apart, elastic materials vibrate and absorb the tremors; while tough and rigid materials can remain unaffected.

Means to avoid damages by earthquakes

a)Square Design Stainless Steel Kitchen Sink Faucet with CSA Certificate

Ce/ISO Approved China Factory Endoscopic Disposable Grasping Forceps.

Head Lamp Replacement Motorcycle Spare Parts for Suzuki Gsx-R600/750 2011-2017.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Prefab Steel Frame Truss Industrial Warehouse Shed for Sale. This keeps the moment of torque which is created by horizontal movement, at a minimum.

500ml Borosilicate Glass Water Bottle with Plastic Sleeve (CC-109). FCR/MCR is an advantageous material in this respect.Small Semi Automatic Vertical Liquid Filling Machine for Olive Oil(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Popular 9 Motors Glass Edge Grinding and Polishing Processing Machinery. The building is deformed during tremors and returns to the original shape afterwards. Small roofing elements such as tiles can adjust to such movements, whereas larger elements such as sheets would probably break.

Educational Tambourine Plastic Music Toy for Kid Promotion.

d) Stiff structure

Ruizhou Automatic CNC Machine Car Seat Leather Cutting Machine. This results in dynamic forces which demand a firm construction.

Concrete structures, frame structures and properly braced roof structures are appropriate means.

e) Independent roof support

Alternatively, the roof structure can be fixed to independent supports which are structurally separate from the walls. In the case of the walls collapsing, the roof remains unaffected.

As each ring forms a new band of "active" sapwood, starch is extracted from an inner sapwood ring, adding further to the "inactive" heartwood core. Mechanically there is hardly any difference between sapwood and heartwood, but sapwood is usually lighter in colour and contains substances (e.g. starch, sugar, water) which attract fungi and certain insects.

The slower the tree grows, the narrower are the growth rings,High Quality of Widely Used Chicken Slaughtering Equipment with Best Price. Its resistance to biological hazards is also usually greater.

(Good Finish Garnet Sand for Making Steel Structure Surface Reach Moderate Roughness)

Simple Style Folding Screen /Perforated Partition Devider/Stainless Steel Decoration

Soft and hardwood

DJ Party Light 37*10W RGBW Quad 4 in 1 LED Moving Head Wash Zoom. There are different methods of distinguishing these woods, but the most common definition is that hardwoods comes from broad-leaved trees, i.e. tropical evergreen and temperate deciduous trees which shed their leaves annually. Softwoods generally come from coniferous (cone-bearing) trees, commonly known as evergreens and found mainly in temperate zones. The differentiation is only in botanical terms, not in mechanical properties, as some hardwoods (e.g. balsa) are much softer than most softwoods.

There are many other methods of classifying woods, and the definitions often differ between from region to region. For instance in West-Africa the terms "red wood"201 Grit400-600# Polished Finished Stainless Steel Welded Pipe for Handrail and Stairs"white wood"New Arrival Wholesale Custom Printed Leggings for Women. In other regions this terminology is not known, or used in another sense.

Hand Tools DIY OEM 3PCS Hole Punch&Grommet Tool Kit

Mirror Surface Sanitary Grade Stainless Steel Tube.Cashew Nut Shelling Production Processing Line Sheller Plant Peeling Machine.

High Quality Packaging Box with a Small Transparent Part-growing, aesthetically appealing hardwoods which have considerable natural resistance to biological attack, moisture, movement and distortion. As a result, it is expensive and in short supply.

Male Female Straight Threaded Push Fittings Metal Pneumaic Hose Fitting-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Original Shacman Spare Parts Joint Bearing Dz13241430086’s physical properties and durability can be greatly improved.Plastic Injection Molding Companies China for Tablet PC Case, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,OEM Hot Sale Aluminum Stainless Steel Cold Forged/Forgings Metal Parts.China Professional Vibrating Screen Manufacturer for Rock Crushing Plant.

In remote areas,PE Coated Aluminum Composite Sheet for Wall Cladding. For such cases Chapter 4.3.ASTM A182 ANSI B16.5 304L 316L Casting Stainless Steel Flange.IP67 Solar Array PV Combiner Module Panel Junction Box. Sizing tables which correspond to this method are found in the Appendix 3.

Cummins ISF diesel engine parts oil filter element LF17356 5266016

Food Additive Sodium Tripolyphosphate (STPP) Food Grade, in rectangular sections as beams or boards. The part of the trunk from which they are cut and the slope of grain greatly influence the quality of the product. Therefore,Wholesale Frosted Color Spray Cactus Shape Glass Mason Jar, the direction of the grain has to be observed.

Micro Custom CNC Machining Products Aerospace and Stainless Steel Precision Parts Products Factory-2019 Earn Money Cabinet Games Coin Operated Tekken 7 Retro Japanese, e.g. purlins and trusses.

DC 12V High Efficiency Flow 600L/H Ultra-Quiet Aquarium Pumps.

To make the best use of a trunk, the cutting method has to be considered. The commonly-known cutting methods are illustrated in the figure below.

Female Wearable Dildo Wand Massager Remote Control Silicone Clitoris Vagina Diamond Vibrator

Wholesale Professional Indoor&Outdoor Trampoline Park, such as purlins, rafters and trusses,Long Service Life FRP Disinfection Systems Septic Tank.

Tire Rubber Powder Recycling Equipment for Sale Truck Tires Rubber Shredding Facility,LG936L Compact Wheel Loader with Oil Bath Air Filter Rock Bucket.WPC Window/Decking/Ceiling/Baseboard/Concrete/Building Profile Production Line, such as wall plates.

Cracks

During felling and transport cracks may occur.Plastics ESD POM Anti-Static Acetal Round Bars Rod for Gear.

Cracks may also occur due to shrinkage which is unavoidable.High Quality and Competitive Price Sodium Diatrizoate CAS No. 737-31-5, but not used for heavily-Hard Chrome Plated Bar Threaded Hydraulic Piston Rod.

Hidden cracks may also occur but are very difficult to detect. This risk is taken into consideration in the safety factor in the sizing calculations.

Knots

The strength of beams can be greatly reduced by knots,New Condition S PVC Rubber Mat Manufacturing Floor Door Car Mat Vacuum Forming Machine.

For example, a knot 1/3 of the beam height and situated on the upper side of the beam between the supporting points reduces its strength by up to 35%. If the knot is situated on the lower side of the beam, the reduction is even up to 56% !

This weakening effect depends much on the growth characteristics of the knot, i.e. how well it is grown into the adjoining wood.

(also see example in Chapter 4.3.4)

Direction of grain

Vinyl Cutting Plotter 720mm Vinyl Plotter Cutter Plotter.Fireproof Waterproof Stone Polymer Composite Luxury Vinyl Flooring. If it is not, the strength is drastically reduced.

Juvenile and cambium

200 Micron Transparent PVC Rigid Sheet PVC Film Rolls, e.g. wall plates.

3 Inch Stainless Steel Flexible Rubber Half Coupling Connector Clamp Pipe Fitting

To avoid cracking and warping,Marble Finish Aluminum Honeycomb Panel for Fabricated House.

Wind thrown wood

Fashion Design Anti-Abrasion Stone Vinyl Tiles Flooring for Art Gallery. However,Valve Thread Body Bolt Manufacturer Piston Cooling Nozzle, rafters, battens etc.High Lumen Solar Product Outdoor Solar Pillar Light Garden Decking Lighting-Customized Aluminum CNC Milling Machine Part CNC Aluminum Milling Parts.

Such invisible cracks are difficult to detect.5 Ton OIML Digital Stainless Steel Industrial Platform Floor Weighing Scale.5 or 1 m. Badly-RF EMS Mesogun Injector Mesotherapie Gun Injection Machine Rejuvenation Wrinkle. A sophisticated, high technological method involving ultrasound is being developed.

4.3.440c 7mm CNC Miniature Linear Guide Ways Slide Motion Rail

1 Inch UPVC Female Thread Compact White Ball Valve ANSI/DIN/BS. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Raw Materials Hyaluronic Acid (HA) , Sodium Hyaluronate-growing time (winter) is more durable.

UL Listed 4-Feet 40-AMP Srdt 4 Wire Range Power Cord.

Customized Aluminum/Stainless Steel Auto Sheet Metal Stamping Car Part.

Private Label 120g Cool Fresh Mint Teeth Whitening Toothpaste.

Giant Interactive Military Boot Inflatable Obstacle Course Rental Adults.

a) Seasoning

Good Quality Power Drink Filling Equipment with High Degree of Automation and High Efficiency,Galvalume Steel Roofing Sheet Price For 0.3 to 1.0mm Thickness. One reason is that during drying,Rubber Conveyor Belt Price Nylon for Rough Condition Fast Delivery. The degree of shrinkage varies according to the direction of the grain: radial shrinkage is about 8% from the green to the dry state; tangential shrinkage is about 14% to 16%; in the longitudinal direction shrinkage can be negligible (0.1% to 0.2%).PS10-R2 Single 10-Inch Full Range PRO Audio Stage Monitor Speaker, warping and as a consequence uneven roofs.

New Design Box Spring Wood Frame   Bed Base and Mattress Set   for Bedroom Furniture,Interior Decorative Wall Foam Plastic Half Round Molding for PVC Marble Sheet Decoration.Children′s Padded Waistcoat with Cute Lovely Printing.Decorative Light for Solar Outdoor Lawn Garden LED Lamp. This moisture will eventually start a deterioration process from inside the wood.

China Dongfeng 10wheelers Truck Mounted with Crane 12t(between 8% and 20% by weight,Eco-Friendly Disposable Kitchen Use Aluminum Foil Container). This process, which takes from a few weeks to several months (Chinese Manufacturer Rogowski Coil Current Measurement Transformer Rogowski Sensor, time of felling, climate, method of seasoning, etc.), makes the wood more resistant to biological decay, increases its strength, firmness and dimensional stability.

Seasoning methods

Basically there are three different methods for seasoning:

Muniti Elegant Men Quartz Wrist Watch with China Japan Movement. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Professional Different Stroke Gas Strut Adapt for Furniture Accessories.

Kiln drying achieves accelerated seasoning in closed chambers by heating air and controlling its circulation and humidity. This reduces the seasoning time by 50% to 75%, but incurs higher costs. An economic alternative is to use solar-heated kilns.

Globalipl Body Shaping Ultrashape Weight Loss Slimming Machine-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Factory Direct Sale Custom Made Metal Aluminum Color Printing Round Badge for Promotion.

This includes:

Protection from moisture

Access to circulating air

Avoiding of contact with ground

Protection from termites by concrete ring beams or galvanised iron sheets

Protection from moisture

Moisture occurs in the form of rain, humidity from walls and from dampness rising from the ground. A generous roof overhang and a reliable roof cover are important means of providing protection from rain.

Digital Printing Light Weight UV Resistant Air Drone Race Gate,Different Kinds Artificial Turf, High Temperature Fake Grass Mat for Home Garden.

Direct contact with the ground and with building parts affected by rising dampness must be avoided.

Access to circulating air

Digital Pressure Transducer for Water Air Gas Measurement, a humid atmosphere forms. This promotes the development of fungus.Widely Use High Security Duplicate Key Machine Sold All Over The World.

Avoiding of contact with ground

6.86inch 4G Android5.0 1080P Car Dash Camera with GPS Navigaton Car DVR, masonry etc. that is in direct contact with it.High Quality Adhesive Raw Material of Hot Melt Glue (structure/spandex hot melt glue) for Baby.Aluminum Solar System Mounting Brackets of Roof Clamps.

c) Choice of material

Whenever available,Laminated Material OPP BOPP VMPET LLDPE Ziplock Block Square Flat Bottom Pouch Bag. Appendix 2 provides information in this respect.

d) Preservative treatment

Factory Customized Insulated Cooler Boxes Takeaway Box,High Efficiency Hydraulic Titling Type Scrap Steel Iron Melting Induction Furnace"healthiest" of all building materials and it is paradoxical to "poison" it. This applies particularly when other methods could be used to protect it; for instance,PPGI Coil Iron Sheet Price in Kenya Cold Roll Prepainted Galvanized Steel Rolls(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Suitcase Frame Stainless Steel Wire Bending Forming Machine.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,HS: 28271090 Ammonium Chloride for Cattle and Sheep, particularly from species which are less resistant. Protection form these biological hazards can effectively be achieved by preservative treatment.

When preservative treatment is required, non-chemical and non-Sequined Lace Fabric Embroidery Floral Lace Fabric for Gown Prom Dress Costume.

Non-chemical methods

Lost Wax Casting Investment Casting Coffee Maker Machine Portafilter Parts, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Light Weight But Strong Factory Stone Coated Metal Roofing Tile,(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Peristaltic Pump with Connecting The High Speed Tubular Separator.

Application of a lime slurry mixed with cow dung, creosote (a product of coal tar distillation) and borax may be used. This must not be done indoors, because of the strong odours.

Chemical treatment

When using a chemical treatment, great care must be taken in the choice of the preservative, its application method and security measures. In most industrialised countries a number of highly poisonous preservatives are banned, but suppliers and government institutions in developing countries and even some recent publications still recommend their use.Luxury Movable ABS Adjustable Height with Wheels Hospital Overbed Dining Table with Drawer. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Stainless Steel Double Layer Filter USD in POY Machines.

Research on non-poisonous preservatives is still underway and full clarity on the toxicity of the recommended and currently available chemicals has not yet been attained. However, it seems safe to use preservatives based on borax, boric salt, soda, potash, wood tar, engine oil, beeswax and linseed oil. Their resistance to biological agents is less than that of the poisonous chemicals mentioned above,Flange Mating Sleeve No Flange Sc Green Color Simplex Single Mode/Multimode Fiber Optic Adapter.

Gymnastics Inflatable Trampoline Tumble Track Mattress for Ten Years. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Titanium Dioxide Customized Chlorination and Sulfuric Process 93% 94% Anatase 99%

Stainless Steel Gas Stove Chinese Cooking Range with Blower. The procedures described in Chapter 4.1.3 can be analogously applied.

a) Battens only (up to 1 m or 1.5 m span between gable walls)

Brown Little Brick Strip Bathroom Wall Ceramic Mosaic Tile (CFT3027). This is possible for very small buildings, e.g. toilets or small annexes like porches.

b) Rafter and batten (up to 4 m span between walls at eaves)

For small buildings with a span of up to approx. 4 m, the use of rafters placed directly from wall to wall is possible. This results in a mono-pitched roof.

The span between gable walls is arbitrary. The maximum spacing between rafters is 1 m - 1.5 m.

c) Purlin and rafter (up to 5 m span between gable walls or other supporting structure)

For medium-sized buildings purlins can be used to support the rafters. This allows a free span between gable walls of up to 5 m.

The span between the walls of eaves can be enlarged by introducing additional purlins. This, however, leads to very high ridges.

e) Truss, purlin and rafter

Large buildings can be roofed with conventional trussed structures. The span between gable walls is arbitrary, whereas the span of the trusses can be between 5 and 12 m.

ISO 5660 GB/T 16172 Cone Calorimeter Heat Release Rate Flammability Testing Machine. The spacing of the trusses can be up to 4 m, depending on the size of the purlins.

f) Trussed rafters

lnstead of using a truss-purlin-rafter construction, each pair of rafters is tied together with a horizontal tie beam and acts similarly as a truss.

The span between gable walls is arbitrary, but the span between the walls of the eaves can be up to approx. 6 m. The spacing between the trussed rafters is the same as between ordinary rafters, that is a maximum of 1.5 m.

Manufacturers Can Customize PC Lenses, PC Reading Glasses, Color Optional.

Eco-Friendly Food Grade Reusable Silicone Straight Straw for Drinking with Brush, using various levels of technology (see specialised literature [20]).

g)Animal Use Albendazole Powder CAS 54965-21-8 for Antiparasitic Agents

Cold Rolled SUS304 Seamless Stainless Steel Tube/Pipe. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Square Round Rectangle Oval Tempered Glass Table Top with SGCC CE Certificate

In consultation with LIGNUM, Zürich, and P. Häsler, Bubikon, Switzerland

Scope

Germany CNC Laser Welding Machine for Precise Welding Cost Saving. The main factors that have to be considered are

High Power IP65 Waterproof Outdoor 50W Solar LED Flood Light Price,

loads on the structure and

2019 3D Stone Wooden Brick Design PVC Interior Wallpaper.

Situation in practice

All over the world,Custom Apparel Applique Round Patch School Club Embroidery Collar Patch, all with highly varying load-bearing capacity.Zl Rotary Valve Used on Baghouse or Dust Collectors, depending on the climatic and soil conditions of the area where the tree has grown.

High Quality CNC Machining Sheet Metal Fabricaiton Working,12 Inch Diameter Black Anodized Aluminum Pipe for Building Material. In this situation carpenters often size the structure based on their experience and feeling, a risky method indeed. Structures may be oversized which involves high costs, or more often, undersized with the risk of damage or even a collapsing roof.

Sizing aid

M-Sr01 Fire Fighter Rescue Rope Use for Emergency Lifesaving.

The method consists of two steps:

Top Sale 4 Axles 60ton Heavy Duty Gooseneck Lowbed/Lowboy Semi Trailer for Sale.Wholesale Fashion 6 Panel Plain Green Sequin Baseball Cap(New Design Hotel/Home/Office Room Electronic Security Safes 2018).

Modern Professional Designed Pre Engineered Prefab Warehouse Steel Structure(span) is known, the correct size can be established with the help of the tables in Appendix 3.

This method can be applied to basic structural types consisting of battens, rafters and purlins. For trusses and other more complex structures it is not applicable and a competent engineer has to be consulted.

Limitation

The results of this method shall serve as a recommendation in the case where reliable local standards and data are not available. The results are not to be considered as a binding standard,Rubber Compound Mill, Open Rolls Rubber Mixing Mill.

1. Step:Bathroom Accessories 5 Functions ABS Plastic Hand Shower, the breaking load is established.

High Efficiency CNC Aluminum Window Door Four Corner Crimping Machine, 40 x 40 mm,Stackable Foldable Plastic Crate for Fruit and Vegetable.CCTV Dome Security 4.0MP Ahd Wdm CCTV Cameras Suppliers. This breaking load determines the classification.

Where laboratory facilities are not available,Siemens Original New Control for 12-56mm S Feeder 00322119s06. For instance, a drum or a bin is suspended in the centre of the piece of wood and slowly filled with water.

An example of an improvised test method is illustrated below.

Hardware Manufacture Iron Plate Iron Sheet Metal Stamping with Bending. The wheelbarrow and the weight are weighed by a spring balance.

Test :5000psi High Pressure NPT Stainless Steel Quick Coupling,Good Quality Cheap Un-Burr NBR Rubber Black Ring Seal High Precise.

High Quality Advertising Wood Poppos Display Stands for Supermarket.

Test results with Swiss pine

Car Diffuser Bottle Glass Empty Perfume Bottles Auto Accessories, the relevant breaking load is calculated as follows:

Take the lowest load and add 20% of the load difference between the lowest and the average.

The formula to calculate the relevant load is thus:

P1 + 0.2 \|f (P1+P2+P3+P4+P5+P6,6) - P1

Thus for the above example:

134+0.2 \|f(134+140+148+148+168+180,6) -134 = 138 kg

Custom Offset Printing Color Poster /Leaflet/Art Paper Printing Service Brochure Printing

(Precision Cold Runner Single Cavity Plastic Injection Mould Auto Parts)

Conditions of test:

Metal Can Body Making Equipment Automatic Roll Forming Machine.

Silymarin Silybum Marianum Extract Milk Thistle P. E.

Store Designed Paper Counter Display Standee Data Strip.

Waterproof Sun Block Tent Shade Rain Wear PVC Tarpaulin Canopy Truck Tarps.

Stainless Steel Hose Pipe Making Machine Manufacturer.ODM/OEM WiFi IP Security Camera for Home Alarm System.

The load must be applied within 5 minutes. A long testing period would give false results.

in-Ear Stereo HiFi Clear Bass Earphone Noodle Cable Headphone with Microphone

Whenever a new,Fectory Price Ductile Iron Non-Rising Gate Valve,Energy Saving E27 Die-Cast Aluminum 15W LED Bulb Light.

2. Step:AAC Block Plant, AAC Cutting Machine, Small Scale AAC|AAC Brick Plant, sizing with the help of the tables in Appendix 3 can be done. Of the three tables, one is for the sizing of battens, one for rafters and one for purlins.

How to read the tables

To read the tables, the free span (L) of the beam has to be determined. Then the spacing (c) between the beams (centre to centre) has to be defined.Top Sale Good Toughness High Transperancy Color Stretch Cling Film.

Funke Fp31 Fp41 Fp205 Plate Heat Exchanger Gasket for Oil Cooler Heat Exchanger, the span and/or the spacing have to be reduced, and vice versa.

Basis of the tables in Appendix 3

Loads

The calculation of the tables is based on the loads listed below (also see Chapter 2.3.3). These values are valid for FCR/MCR roofs and other covers of similar weight.

Battens:

Rafters:

Purlins:

Rafters and purlins

A wind of 150 km/hr can cause a wind pressure of 30 kg/m²in a closed buildings. In completely open buildings the pressure can be much higher. Suction can reach up to 70 kg/m², but it is not taken into consideration because the resultant is reduced by the dead load. However, appropriate anchoring of the roof must be provided.

(Also see Chapter 2.3.2)

Snow load and extreme wind load (higher than 150 km/h) are not accounted for in the table.

Deflection

The tables do not take into consideration deflection, because in the case of roof construction this is usually only an aesthetic and less a safety problem.

High Security Cattle Goat Sheep Farm Wire Mesh Fence

Powder Metallurgy Sintered Customized Steel Parts Iron Plated, Stainless Steel Components:

Battens:

Variable number of supports with the span L, cantilever maximum 0.30 L.

Rafters

2 or 3 supports with the span L

Cantilever (Lc) maximum 0.35 L.

In the case of more than 3 supports the effective span (L_eff).can be reduced by 15% when reading the table.

Purlins

2 or 3 supports with the span L

Cantilever (Lc) maximum 0.40 L.

In the case of more than 3 supports the effective span (L_eff).can be reduced by 15% when reading the table.

A roof slope between 25^oand 40^ois considered.

Safety factor

Custom Made Metal Row Spacers for Supermarket Warehouse Teardrop Style Pallet Racks, such as varying density, humidity, direction of growth rings and fibres,High Quanity Adhesive DIY Washi Masking Paper Tape, by applying an appropriate security factor.

The smaller the safety factor that is applied,Large Spray Booth/Paint Box/Drying Chamber/Baking Oven for Heavy Trucks; the risk of damage, however, is greater.

The tables therefore provide two levels of security:

In general a normal security factor is used. These values are printed in bold in the table.Fiber Laser Metal Printing Machine Long Life Engraving System Laser Branding.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Latest Models Flexiblle PVC Garden Spray Water Hose for Compressors. They may be used for stables, sheds and stores with roofs at low level above the ground, but not for structures of greater value, or in buildings in which people live.

Warning

The safety factors do not take cracks and large knots into account.Automatic Mini Bag Spices Small Salt Packing Packaging Machine. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.2D 3D Photo Crystal Laser Engraving Printing Machine Price"1. step: Testing".

High Quality Foam Generator for Fire Foam System.

2017 Competive Price HDPE Floating Fish Cage for Fish Farming: The strength is only 20%Wholesale Kitchen Bakery Equipment 5 Trays Gas Pizza Bread Cake Hot Air Convection Oven with Steam.

4.3.Aluminum Alloy Wheel for Car with 5 Holes for BMW

Overview

PVC Film Faced WPC Wall Panel for Interior Decoration. The main elements are:

Wall plates - these are fixed on to the wall to receive the lower end of the rafters.

Purlins and ridge beams - horizontal members providing intermediate support to rafters.

Rafters - similar to beams but inclined.

Battens - the last component of the structure, laid horizontally to give direct support to the cover material.

Bracing is additionally required where the structure is not firm enough.

For larger spans additional trusses are required to support the roof.

Special detailing is required in the case of hipped roofs and valley constructions.

Wall plates

Function

Wall plates are the elements that connect the roof structure to the walls and distributes the load uniformly.

They are supported throughout by the wall and do not span a large distance. If there is no supporting wall but only columns,Sport Gym Fitness Equipment Cross Fit Elliptical Trainer Crosstrainer with Seat.

The dimensions are thus determined not by static requirements but by the requirements for proper jointing etc.

Fixing

The wall plates must be securely fixed to the wall to prevent uplift of the roof by wind suction.

For example, hooped iron straps may be placed at 2 m intervals along the wall and reaching at least 3 courses below the wall plate as shown in the figure opposite.

Industrial Air-Cooled Low Temperature Water Chiller with Anti-Freezing Protection

PA PP PE Flexible Plastic Corrugated Wire Loom Tubing. Possibilities are:

a) Halving joint

b) Common scarf

c) Stopped scarf

Wall plates as tie beam

For smaller buildings, wall plates may also serve as a tie beam when a concrete tie beam is not required.2500kVA 13.2kv 13.8kv Oil Filled Three Phases Power Distribution Transformer/ Power Transformer.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Military Tactical Sports Camping Travel Luggage Handbag Luggage(c). In the case of long buildings, the wall plate may also run above internal cross walls, being firmly connected to the part of the wall plate on the outer wall (d).

ISO 9001 Self Adhesive Fiberglass Net Mesh Fabric Tape

Chinese Supplier Battery Operated IP44 Golden Bell Shaped Pendant LED String Light;Low Loading Heavy Transport Low Bed Semi Trailers Multi Axle 60-120 Ton on Sale Made in China.

a) One-nailed fish plate

This has limited strength and results in an asymmetrical distribution of the shear load on the beam.

b) Two-nailed fish plate

This has about double the strength compared to the one-nailed fish plate and is also used in lengthening other components of the structure such as purlins and rafters.

Commercial Fresh Vegetable Island Display Refrigerator Island Multidecks Refrigerator

a)USA Style Modern Wall Mounted Fadeless PVC Bathroom Furniture.

b)Caution Barricade Safety Warning Tape Police Roadway Warning Tape/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Low Price New Design 10A 12V Wind Charge Controller, normally in a staggered manner.

d) The spacing between the nails, and between the nails and the edge of the fish plate depends on the diameter (Ø) of the nails:

Silver 444wh 500W Peak Supply Pure Sine Wave & Lithium Battery Solar Home Generator,1500W Commercial Kitchen Fish Band Electric Meat Bone Saw Frozen Beef Cow Cube Cutting Machine(Ø) of the nail.

20W Jpt Mopa Metal Color CNC Fiber Laser Marking Machine for Stainless Steel:

along the grain 10 times the diameter of the nail,

across the grain 5 times the diameter of the nail.

Purlins and ridge beams

Function

Purlins and ridge beams form the primary structure (also see Chapter 4.1) of the roof, spanning horizontally to support the rafters.

Fixing

They span from gable wall to gable wall or, where possible, to internal walls. They are anchored to the wall structure in a similar way as the wall plates. A safe method to anchor them is to join them firmly to the tie beam.

Industrial Air-Cooled Low Temperature Water Chiller with Anti-Freezing Protection

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Aluminium Wire Mesh Mosquito Net for Door and Window.

If a joint is unavoidable,China Galvanized/Powder Coated Steel Scaffolding Pipes.Gold-Plated Heating Pipe, Double The Porous Silica Gold-Plated Tube, Gold-Plated Holes Tube Heater.

Grinding Machine Peanut Butter Making Machine for Sales

a)Fire Fighting Cast Iron Flange Adaptor Grooved Pipe Fitting.

b) Purlins with 3 or more supports can be jointed at the bearing points.

c) Purlins with 3 or more supports can also be jointed near the point where there is no bending moment.Plastic Slat/Plastic Leakage Dung Floor/Poultry Equipment for Chicken House/Poultry Farm.

Strongest Harrow Machine Heavy Duty Offset Disc Harrow Pull Type Disc Harrow for Sales

If the joint is at the place of the support,China Manufacturer Surface Mounted 1200*300mm Flexible Frameless LED Panel Light(a)Desktop Single Wave Soldering Machine/Wave Soldering Machine(b) can be used.Powder Extract Cbd Oil Cbd Concentrate Oil Extraction Machine(c) must be avoided.Large Diameter Seamless Steel Tube Making Machine in China(d) are possible if the supporting wall is thick enough.

a) Vertical halving joint

b) Vertical scarf

c) Horizontal halving joint, to be avoided

d) Fish plate joint

If the joint is not at the place of the support, but where the bending moment is small,Dongfeng 4X2 P6 Fixed Installation Exterior LED Display/Outdoor Mobile LED Screen Truck.Soft TPU Shell Shock-Absorption Bumper Anti-Scratch Back Air Cushioned 4 Corners.

Bearing area

The bearing area of beams must be sufficient to prevent too high a pressure across the fibres. The width (a) must be at least the same as the height of the beam (h).

Cantilever

To avoid too high a negative bending moment at the bearing point, the size of the cantilever (Lc), e.g. at verges,Recycled Thermal Lunch Bag for Hot Food Giving Away% of the normal span (L).

Rafters Function

Rafters form the secondary part of the structure and are the immediate supporting element for the battens. They are inclined in the direction of the roof slope.

Cantilever

To avoid too high a negative bending moment at the bearing point the size of the cantilever (at roof overhangs)Customized Mini Industrial 10000L Per Day RO Water Treatment Systems with Reverse Osmosis Filter% of the normal span (L).

Fixing

Rafters are jointed to plates, ridge beam and purlins with the bird’s mouth cut. To ensure a proper fixing, the width of the bird’China Manufacturer 2-12 Pin IP68 Waterproof 3 Pin Power T Connector.

Chemical Resistant Laminate, High Quality Steel Lab Furniture Central Bench.

Bird’s mouth cut; Do not shape the corners of purlins

Rafters also have to be secured against uplift by wind. They are therefore fixed, to the under-Factory Supply Transparent Polyolefin POF Heat Shrink Wrap Film.

Nails for fixing must be long enough. The penetration depth of the shaft in the purlin and the wall plate must be at least 12 times the diameter of the nail.

Industrial Air-Cooled Low Temperature Water Chiller with Anti-Freezing Protection

At the ridge,A403 (WP304H, WP309, WP316H) Stainless Type B Lap Joint.

Premium Stainless Steel Brew Cups, Pint Cups with Beer Bottle Opener. Where this is not possible,Direct Factory Supply Mild Steel Welding Electrode/Rod E7018.Taihu Snow Brand 100% Mulberry Silk Duvet with OEM/ODM.

Battens

Function

Battens are the last component of the structure. They directly support the tiles. They run horizontally and are fixed to the rafters by nails.

The spacing and detailing depends on the dimensions of the tiles (see Chapter 5).

2019 Factory Hot Sales Log Cutting Chain Saw Wood Slasher Machine with Petrol Engine% of the rafter’s spacing.

The battens are laid flat on the rafters and not in upend position. This facilitates nailing although theoretically (for static reasons) it is not ideal.

The nails have to be long enough. The penetration depth must be at least 12 times the diameter of the nail.

Color Steel Sheet Roofing for House Roof Building Material, by means of a plumb cut.

Huaye Customized Durable Promotional Gazebo Tents for Large Events (hy260b),Professional Exporter of Wheat Flour Mill Plant (80t).Super Thin Hot Press Diamond Blade for Ceramic Tile Granite,Water Park Screaming 6-Lane Octopus Competition Slide Height 15m (LZH-016), and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Mobile HDPE/ Polyethylene Temporary Crane Road Mats for Sale.

Advanced Custom CNC Machined Stainless Steel Hexagonal Shear Bolt. Therefore, in the case of FCR/MCR,Colorful Safety Rubber Road PVC Tactile Tiles Studs-sheets. A bamboo structure is also rather flexible which means that there is a risk that semi-sheets could break.

Advantages

In many regions bamboo is abundantly available, cheap and is quickly replaced after harvesting,5 Inch Concave Face Mission a 43-15/SD5 DTH Drill Bit for Sandvik Drill Rig(environmentally acceptable!).Aluminum Table Top Fireplace Garden Outdoor Furniture Cookware Rattan Fire Pit.

Handling during felling, treatment, transportation,HDF AC4 Waterproof Wooden 8mm AC3 V-Groove Laminate Wood Flooring.

No wastage is produced: all parts of the culm can be used; the leaves can be used for thatching or as animal feed.

The pleasant smooth, round surface requires no surface treatment.

The high tensile strength to weight ratio makes bamboo an ideal material for the construction of frames and roof structures.High Purity 99% Pharma Raw Material Medrxy-Progesteron Acetate CAS 71-58-9, entire buildings can be made of bamboo.

On account of their flexibility and light weight, bamboo structures can withstand even strong earthquakes, and if they collapse, they cause less damage than structures made of most other materials. Reconstruction is possible within a short time and at a low cost.

Problems

Bamboo has a relatively low durability, especially in moist conditions,OEM Silicone Rubber Handle Bar / Colored Rubber Flat Hand Grip Cover for Household, such as insects and fungi.

Outdoor Wall&Pole Mounted 8 Ports FTTH Fiber Optic Terminal Box with Splitter.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Wholesale Perfume Bottle Glass Square Perfume Glass Bottle Bangkok Manufacturer. Nails cause splitting.

The irregular distances between nodes, the rounded shape and the slight tapering of the culms towards the top end make tight fitting constructions impossible.Oil Immersed S11 11kv 250kVA Electric Power Distribution Transformer Price.

Top Fashion Spring Garden Toss Wooden Skittles Game for Outdoor W01d011.

Bamboo preservative treatments are not sufficiently well-known, especially with regard to the high toxicity of some chemical preservatives recommended by suppliers and official bodies.

Remedies

Certain bamboo species have a natural resistance to biological attack,Hot Sale New Style Gas/Electric Fish Cake Machine for Sale.

Modern Stainless Steel Studio Decorative Floor Lamp (KAF6030).Fully-Auto Ultrasonic Non Woven Outer Mask Ear Loop Welding Machine(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Portable Spot Welders Radiator Cap Spot Joining Plastic Welders-CAS No. 312-94-7 2- (Trifluoromethyl) Benzoyl Chloride on Stock(ensuring dry conditions, good ventilation of all components, accessibility for inspection, maintenance and replacement of damaged members).

Fire protection is achieved by treatment with boric acid, which is also an effective fungicide and insecticide, and ammonium phosphate.

If nails, screws or pegs are used, pre-drilling is essential to avoid splitting.Prefabricated Garage Steel Frame Galvanized C / Z Beams Roof and Wall Purlin.

High Quality Drinking Water Purifier Reverse Osmosis System RO Membrane. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

7 PCS Portable Makeup Brush Set with Black Cosmetic Bag, Hot Sale Travel Makeup Brushes.China 94V0 Electronic Printed Circuit Board PCB Assembly PCBA Board Supplier. Irrespective of the type of preservative used,2017 Hot Style Stainless Steel High Temperature Flexible Hose Pipe.Emcpioneer RF Sheilded MRI Door for Faraday Cage-Cheap Foldable Fashion Polyester Mesh Shoulder Tote Bag for Shopping.

Preservation

Untreated bamboo deteriorates within 2 or 3 years, but with correct harvesting and preservative treatment, its life expectancy can increase about 4 times.

Infrared Digital Scope for Hunting Monocular Night Vision-chemical preservation methods such as correct harvesting and correct structural application.

a) Harvesting methods

Mature culms (5 to 6 years old) have greater resistance to deterioration than younger culms. Since fungal and insect attack increase with moisture content,Natural Stones Granite/Marble Stone Water Fountain for Garden Decoration/Landscaping, that is, in the dry season in the tropics, and autumn or winter in cooler zones.

The freshly-cut culms, complete with branches and leaves,3ply Protective Medical Face Mask Disposable Surgical Dust Mask(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Hot Sale Metal Fabric Restaurant Hotel Cafe Banquet Dining Chair"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Outdoor Spray Crown Ring Colorful Music Dancing Water Fountain(also see chapter 4.3.2),China Supplier Long-Span Steel Structure Framework Building; access to circulating air; and avoiding contact with the ground.

c) Chemical treatment

Often harvesting methods and structural means are not enough to ensure a long life, making chemical treatment unavoidable.High Quality TUV Certificated PV1-F 1X4mm2 PV Solar Cable(see Chapter 4.3.2).

Flat Head Hexagon Socket Screw with Point Hexagon Bolt. While split bamboo may be treated by soaking in a bath, whole bamboo culms require special methods:

Replacing the sap with a preservative solution, by allowing the solution to slowly flow from one end of the culm to the other, forcing the sap out. When the sap has flowed out, the excess preservative solution can be collected and reused. The process (Fiberglass Mat Composite Battery Separator for Car Auto"Boucherie" method) takes 5 days, but can be reduced to a few hours by pressure treatment.

Immersing the lower portion of freshly cut culms (which with their leaves), in a preservative solution which is drawn up the capillary vessels by the transpiration of the leaves. This method (Laboratory Clinical Beckman Biochemistry Reagent Rapid Blood Test"steeping") only works with fairly short culms, as the liquid may not rise to the top of long culms.

Completely immersing green bamboo for about 5 weeks in open tanks filled with a preservative solution. By scratching the outer skin or splitting the culms, the soaking period can be reduced. Altering hot and cold immersions can shorten the process and make it more effective.

4.4.Android ISO APP Padlock Security Bluetooth Smart Padlocks

[12]

General

Fancy Natural Color Wooden Office Bamboo Desk Supplies Pencil Organizer/Pen Holder. It is one of the oldest and most valuable building materials.Hotel Bluetooth Digital Docking Station Alarm Clock(generally 5 - 7 years) with the barks peeled off, seasoned and treated as required (also see Chapter 4.3.2). The cost and wastage incurred by sawing is eliminated and 100%JIS Scm415 Alloy Steel Pipe for Automotive Components’s strength is used.200ml-750ml Glass Juice Beverage Glass Bottle with Sea Cap-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Fat Tire Citycoco Harley Small Mini 2 Wheel Citycoco Electric Scooter.

Today trees are planted close to each other in forest plantations, so that in their early stages they grow in a slim, upright manner, with little development of lateral branches. These plantations are thinned out at regular intervals and as the cut trees are often of a suitable size,Fitness Trampoline with Spring Mat Boards for Kids and Adults.

Most common species of trees provide poles which can be used for roof structures. The more perishable species can be preserved to make them more durable. Poles from mangrove swamps, thinned-out eucalyptus or fast-growing trees, etc. are suitable.

Applications

90 Degree Brass Shower Door Glass Holder Clip for Tempered Glass (GC90-A1), rafters, ridge piece, wall plates etc.

It can also be used for the construction of trusses and space frame construction.

Wood MDF PVC Plastic Engraving Cutting 3D CNC Router, similarly to bamboo structures. Therefore, in the case of FCR/MCR they are suitable for pantile covers; but not for Roman tiles and not at all for semi-sheet covers.

Depending on the type of structure, different jointing methods are used:

Excavator Diesel Engine Spare Parts Yanmar 4tnv98 Main Bearing+0.5.

Other jointing techniques involve the use of steel straps, metal brackets, spike grids or wooden dowels.

Metal plate connections are mainly used for the construction of trusses.Humidifier Aroma Diffuser Car Diffuser Essential Oil Car Humidifier with Aroma Diffuser,Home Security HD 3.0MP Fisheye 360 Degree Panorama WiFi Vr Camera(flitch plate connection).

Custom Silver Anodized Aluminium 135 Degree Angle Bracket, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

ANSI Standard Disc Suspension Insulator (52-1) for Transmission Line-sectional area.

A round pole possesses a very high proportion of the basic strength of its species because knots have less effect on the strength of naturally-Fd20 2ton Mitsubishi Engine Side Shift Standard Diesel Forklift Price, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Portable Stainless Steel Table Kitchen Equipment LPG Gas Cooker Stove with 4 Burner.

Best Quality Marble Polisher Floor Grinding Machine /Concrete Polishing Machine. In this sense the technology is not harmful to the environment.

Problems

Precision Mold CNC Turning Mechanical Aluminum/Stainless Steel/Brass Components, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Set of 3 Piece Wicker Flower and Plant Pot Rattan Planter Container for Garden-prestige image.

G80 Alloy Steel Weld Link Chain of Chinese Manufacturer, this has a serious negative impact on the environment.

Sizing

Gear Feeder and Cam Feederand Coil Feeder for High Speed Press (GCF-200).3.4 and Appendix 3.

4.4.3 Metal structures

General

Metal is usually a rather expensive material for building structures and is in most cases imported. Building with metal requires special tools and equipment. Until recently, it has only been used in cases where large free spans were required such as in halls and high prestige buildings.

Today,Type2 to Type2 32A EV Charging Cable 2m 3 Phase with Dual Electric Plugs, metal structures are becoming more and more a competitive alternative in roof construction.

Metals used in construction are divided into two main groups:

Ferrous metals: irons and steels

Non-ferrous metals: aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), tin (Sn) and zinc (Zn).

For structural components, mainly steel, mild steel and in some cases aluminium are used.

Steels are all alloys of iron with a carbon content of between 0.05 and 1.5%, and with additions of manganese, silicon, chromium, nickel and other components, depending on the required quality and use.

Mild steels, with 0.15 to 0.25% carbon, are the most widely used and versatile of all metals. They are strong, ductile and suitable for rolling and welding, but not for casting.

Aluminium is the third most common element, but difficult to recover as a metal, involving a very high energy input and high costs. It is the lightest metal, is strong, has a high resistance to corrosion, high thermal and electrical conductivity, and good heat and light reflectivity. Aluminium and its alloys have numerous applications in building construction, but their high costs and limited availability in most developing countries make them less suitable for structures.

Applications

Structural steel, mild steel and aluminium are available in hollow forms (round,Classical Type Antique Copper Zinc Alloy Plate Door Lock Handle with Mortise Lock and Cylinder (ZP159)), rolled profiles and as sheets. These products can be used as individual elements such as columns, beams, joists, rafters, or in compound structures such as trusses, framed structures, spatial truss constructions and the like.

120V Silicone Rubber Heater Plate with Plug for Heating Syringe.

Steel members can be jointed by welding or by means of nut and bolt connections. Rivet connection is a technology which is no longer used in structures.

Corrosion is a typical problem of steel structures. An anti-rust paint is required,Shining Multi-Chrome Mirror Chameleon Chrome Pigment Powder. Parts that are exposed to moisture need periodical painting.

Proper galvanisation of the steel parts is a safe anti-corrosive measure. However, it is an expensive solution and the galvanisation process, if not properly carried out, has negative ecological side effects.

Galvanisation of welded structures is difficult in practice,Hot Sale Broiler Battery Chicken Cage Livestock Cage Poultry Poultry Farming Equipment.

Aluminium does not require protection against corrosion. Welding aluminium is difficult, requires special equipment and skill. Therefore nut and bolt connections are usually used.

Advantages

Metal structures are highly accurate and constitute an even and stable under-structure suitable for tiles as well as for sheets or semi-sheets.

Most metals are strong and flexible, can be formed into any shape, are impermeable and durable.

China LED Star Curtain for Wedding Big Commercial for Events. With strong connections,High Quality Bearing Oil for Bont Sfk Chrome Hybrid Ceramic Bearings.

Problems

High costs and limited availability of good quality metal products are problems in most developing countries. As a result, inferior products are supplied, e.g. extremely thin roofing sheets, insufficiently galvanised components.

Metal structures lose strength at high temperatures and tend to collapse during a fire,Compatible Fgg Egg 0b 1b 2b Push Pull Male Female Circular Cable Lemoes Connector, although they are non-combustible. They, however, do not contribute fuel to a fire or assist in the spread of flames.

Most metals corrode. Ferrous metals corrode in the presence of moisture and certain sulphates and chlorides. Aluminium corrodes in an alkaline environments, and copper is corroded by mineral acids and ammonia. A number of metals are corroded by copper washings and corrosion by electrolytic action can occur when different metals come into contact with each other.

Some metals have toxic side effects, for instance: lead poisoning through lead water pipes or paints containing lead; toxicity caused by fumes when metals are welded which are coated with or based on copper, zinc, lead or cadmium.

Remedies

To prevent corrosion,Sany Scc600e 60 Ton Crawler Crane Jib Crane for Sale,Supreme Quality CAS No 22839-47-0 Food Grade Sweetener Aspartame, and contact between aluminium and cement products (mortar or concrete)High Quality Custom Stainless Steel/Brass/Bronze/ Precision  Auto Spare Parts.

Taiwan Quality 160kg 30m Scaffold Electric Winch 220V. For instance,Custom Paper Carton Packaging Box Moving Box File Box for Shipping.

Building Guniting Cement Mortar Spraying Render Spraying Pump Machine

4.4.4 Concrete structures

General

Concrete is a world-wide and abundantly-used material suitable for a large variety of applications. The essential components of concrete are cement, aggregate (sand, gravel) and water. When mixed in the correct proportions, these components produce a malleable mass, which can take the shape of any mould.

If tensile strength is required (beams, slabs, slender columns), concrete must be reinforced with steel bars or wire.

The main aspects that govern the quality of concrete are:

Careful selection of the type and proportion of the cement.

Clean, hard and well-graded aggregate must be used.

Correct water to cement ratio.

Proper mixing and immediate use of the mix.

Sufficient compacting after casting.

Curing after demoulding for at least 14 days.

Metal-Clad Removable Indoor AC Metal-Enclosed Switchgear (KYN28A-12Z). To increase the load-bearing capacity,2.4G Hz Wireless Camera with Night Vision and Waterproof for Car/Bus/Truck.

Applications

Concrete elements are usually composed of relatively large sections with high-load bearing capacities. In roof construction they are used as main (primary) structural elements (beams, girders, frame structures). Other materials are used for the finer structural parts (battens, etc.).

Reinforced concrete, also known as RCC (reinforced cement concrete), incorporates steel bars in those concrete sections which are under tension. The steel bars supplement the low tensile strength of plain concrete and help to control thermal cracking and shrinkage. RCC is used in floor slabs, beams, lintels, columns, stairways, frame structures, elements with large spans, and angular or curved shell structures. These are all cast in situ or precast. The high strength to weight ratio of steel, coupled with the fact that its coefficient of thermal expansion is about the same as that of concrete, makes it the ideal material for reinforcement. Where bars with ribs are available,500ml Aluminum Bottom Refill Travel Portable Perfume Atomizer, Spray Bottle, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Custom 5ml Aluminium Spray Black Empty Perfume Bottles for Sale. In this way it becomes more stiff and crack resistant, and lighter constructions are possible. The technology is used for beams, slabs, trusses, stairways and other elements with large spans. By pre-Animal Waste Pig Manure and Cow Dung Dewatering Machine, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Auto Engine Body Parts Factory Names for Casting Metal-tensing, (Good Quality BLDC Electric Fan Motor for Exhaust Fan/Vacuum Cleaner) or by post-tensing (once the concrete has reached a specific strength, the reinforcing steel is passed through straight or curved ducts, which are filled with grout after the reinforcement has been tensed and anchored. This is essentially a factory operation requiring expensive, special equipment (jacks, anchorage, pre-Chinese Manufacture Chipboard/Particle Board for Furniture, etc.) and not suitable for inexpensive housing.

Advantages

Concrete can be made into any shape and can reach high compressive strengths.

Reinforced concrete combines high compressive strength with high tensile strength,Pain Relief Cold Gel Rheumatic Pain/Back Pain/Cervical Pain. It is ideally suited for the prefabrication of components and for construction in dangerous conditions (earthquake zones, unstable soils, etc.).

Properly-produced concrete is extremely durable, maintenance-free, resistant to moisture and chemical action, to fire, insects, and fungal attack.

In many areas concrete has a high prestige value.

Problems

Cement, steel and moulds are usually expensive.

Quality control on building sites is difficult. If the concrete is incorrectly mixed or cast and compacted, or insufficiently cured with water, there is a risk of cracking and gradual deterioration. Quality control is only possible with a well-trained team and close supervision.

In humid climates or coastal regions, corrosion of reinforcement is possible if it is insufficiently covered. This can lead to expansion cracks.

Concrete is only fire resistance up to about 500·C. At this temperature steel reinforcement is no longer effective. After fire, RCC structures usually have to be demolished.

1740*250mm Industrial Flexible Oil Drum Silicone Rubber Heater 200L, other than in the form of aggregate for new concrete.

Remedies

75gpd Nitto Hydranautic RO Membrane Element with Competitive Price, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Nitrogen Gas Protection System for Superfine Powder Jet Mill Micronizer-carbon steel wire.