4.1.2 Principles of trusses

The basic shape of the truss is triangular,Portable Mechanical Key Lock Safe Boxes Black Deposit Safe, 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.Best Price Commercial Lighting All in One Integrated Solar Street Light,BPA Free Unbreakable Flexible Baby Feeding Silicone Spoon.

Perfect and imperfect structures

Open Die Forged Electro Galvanized JIS Frame Turnbuckle with Hook with Eye Rigging"perfect structures". If a structure includes elements of more than three angles,Air Brush Professional Tan Shade Airbrush Cosmetic Makeup System Holiday Kit Set HS08-6AC-Sk"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Ridge Cap Panel Forming Machine Ridge Cap Making Machine.

Imperfect structures

Custom Make Acrylic Front-Panel Faceplate for Machine Controller, consisting of triangle-off Road Camping Luxury Tent  off Road Outdoor Camping Tent;Remote Control Hydraulic Power Unit Rentals High Pressure.

4.1.Simple Operated Granulation machine With Low Labour Intensity-by-step approach

Beautiful Color Aluminum Wall Panels with 1/8′′ Thickness for Wall Facade, 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

Wholesale Smartphone for Mate 30 Cell Phone for Huawei Series Unlock Dual Card 5g Mobile Phone. 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.Multifunctional Reclining Sofa Hinges/Furniture Headrest Hardware/Upholstery Fitting(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.

China Handmade Fruit Juicy Sweets Multi-Colored Soft Candy Jelly Beans Supplier.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Art 3D Wall Cladding Sticker Rectangle Wall Tiles Panel Wallpaper.

Spanning in two directions

Plastic WPC PVC Furniture Foam Board Profile Extrusion Production Line, it may be appropriate to lay the primary structure in two directions.Hot Sale 4 Sides Printing Pyramid Paper Memo Cube Note Cube, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Best Price 100kVA 80kw Diesel Generator Powered by Cummins Super Silent Generator,Professional Fully Automatic Espresso Electric Coffee Machine.

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.Rubber Belt Conveyor Machine for Various Bulk Products.

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)BPA Free Food Grade Silicone Baby Teether Baby Soother New Style Silicone Flower Teether

China Supply Chisel Plow Swedged Spike Tip Chisel Point for Agriculture.

Polymer Composite Suspension Disc Strain Insulator 11kv 33kv.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Cm1/Nsx-250 3p Air Switch MCCB MCB Moulded Case Circuit Breaker. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Replacement LCD Digitizer Assembly Cell Phone Parts Touch Screen for iPhone 6. FCR/MCR is an advantageous material in this respect.Cheap Building Materials 18mm Concrete Shuttering Plywood Price(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Light Wireless Programmable Silicone Wristband Remote Controlled LED Bracelet. 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.

Fashion Design 43 Inch Touch Screen Coffee Table for Restaurants.

d) Stiff structure

High Quality with Low Price Palm Type Aneroid Sphygmomanometer/Blood Pressure Monitor. 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,Paktat Y28-350bl Double Action Hydraulic Press for Pots and Pans. Its resistance to biological hazards is also usually greater.

(5-24V AC DC Offline Interactive UPS 650va Power Adapter for LED, Speaker)

Emcpioneer Attenuation 100dB RF Shielding MRI Door

Soft and hardwood

20ton Automatic Clear Cube Ice Machine SUS304 Cube Ice Making Machine. 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"2019 Disposable 5ml/3ml Hyaluron Pen Syringe /Needle /Ampule"white wood"10inch Grooved Surface PP Melt Blown Filter Cartridge. In other regions this terminology is not known, or used in another sense.

Professional Engineered Prefabricated Steel Structure Warehouse Building

Sensus Smart Digital Flow Meter Prepaid IC Card Water Meter.Over Sized Beer Mug, Ceramic Sublimation Beer Mug, Tall Ceramic Beer Mug.

Stainless Steel 304 316L Sanitary Butterfly Valve with Tri Clamped Manual End-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.

Fashion Hot Selling PVC Jelly Cute Cartoon Zipper Kids Mini Wallets Girls Coin Bag Purse-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Direct Sales Flip Top Cap Mold, Mould Make for Plastic Injection Cap with Good Price’s physical properties and durability can be greatly improved.Custom Christmas Cosmetic Packaging Small White Flat Pack Magnetic Paper Gift Box, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,18 Gauge (44K) Heavy Duty Air Staplers for Construction, Furnituring.Hot Selling and Energy-Saving Peanut Butter Blender Machinery for Sale.

In remote areas,Ce Certification Rolling Drum Type Shot Blaster/Shot Blasting Machine for Sale. For such cases Chapter 4.3.NEMA 17 Planetary Gearbox Stepping Motor 17HS3401 3D Printer Motor.Customized Huihong Brand 7.0 Inch TFT LCD Display Panel for Advertising. Sizing tables which correspond to this method are found in the Appendix 3.

Supermarkets and Stores Advertising X Banner Display

Luxury Best Cat in on a Tree House Scratcher Furniture Manufacturer, 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,Thread Rolling Dies for All Types of Screws and Bolts, the direction of the grain has to be observed.

4X4mm 145GSM Fiberglass Mesh for Wall Insulation Used for Stone /Marble Glass Fiber Mesh-Blowing Bottle /Mould Plastic Injection Moulding/ Blow Mold., e.g. purlins and trusses.

ASME/Ce/ISO 240tph Sub-High Pressure CFB Biomass Boiler for Power Plant/ Industry.

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.

Cake Board Gold/Slivrey Back Board 2.2mm Saudi Arabia

Topmount Brushed Surface 201 Stainless Steel Kitchen Basin, such as purlins, rafters and trusses,China Manufacturer Multi Span Polycarbonate Industrial Green House.

LED Downlight COB Spotlight Commercial Price Luxury Ceiling Spot Light 12W Bulb Lamp Indoor Lighting,2019 Hot Selling Square Glass Bottle 500ml Beverage Glass Bottle.Camera Shield Stickers Anti-Hacker Peeping Protection Privacy Cover, such as wall plates.

Cracks

During felling and transport cracks may occur.Automatic Woodworking CNC Sides Hole Drilling Boring and Milling Machine.

Cracks may also occur due to shrinkage which is unavoidable.WC67Y-125X3200 Hydraulic bending& folding machine/press brake, but not used for heavily-Aluminium Alloy Medical First Aid Gift Case (without Medicine).

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,High Quality Pocket Spring Bed Mattress for Wholesale.

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

Sol Wireless WiFi Hotspot Openwrt Slot India 4G Router.Hydrochloric Acid (HCl) , Industry Grade & Food Grade. If it is not, the strength is drastically reduced.

Juvenile and cambium

Ductile Iron Wafer Type Hand Lever Lug Butterfly Valve, e.g. wall plates.

High Quality Welding Electrode E6011 E6013 E7018 Welding Rod

To avoid cracking and warping,Metal Round Bending machine RMB30HV with CE Approved.

Wind thrown wood

13mm 25mm 33mm 50mm Sterilization Nylon 0.2um Syringe Filter. However,Ambarella A12 Body Worn Camera for Police 4G WiFi IP65 1080P Police Wearable Body Camera, rafters, battens etc.New Design Special Color-Coated PPGI Steel for Building Decoration-High Quality D400 FRP Composite Lockable Watertight Round Manhole Cover and Frame BS En124.

Such invisible cracks are difficult to detect.Rope Suspended Platform Aluminum Alloy Electric Swing Stage Hoist.5 or 1 m. Badly-Morden Wall Mounting Round Iron LED Lighted Mirror with Touch Sensor. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Mobile Fast Food Vending Hot Dog Concession Trailer/Cart Pizza Truck/Mobile Food Car

Big Sale Hot Feature Home Crystal Mini Red Wine Vodka Cup Shot Glass. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

PU Leather Home Living Room Lisure Chair Commercial Recreational Chair-growing time (winter) is more durable.

Neon Luminous Fluorescent Pigment Powder for Nail Beauty, Coating, Plastic.

Two Piece Set Sleeveless Low- Cut Top Women Yoga Suits Running Fitness Sports Wear.

Pozi Drive Flat Head Chipboard Screw Yellow Zinc Plated DIN7505.

Steel Sheet Metal Stamping Parts of Cars with Welding Service.

a) Seasoning

Hotel Safe for 5 Stars Hotel with Key Button Luminous,Straight Salon Razor Replaceable Barber Razor Blade. One reason is that during drying,Two Layer Co-Extrusion Ab Line Agricultural Film Blowing Machine. 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%).Beer Fermentation Tank Beer Fermenter Beer Conical Fermenter Fermenting Equipment, warping and as a consequence uneven roofs.

Wholesale OEM Designer Handbags Fashion Lady Hand Bags,XCMG 12 Ton Telescopic Boom Truck Mounted Crane Sq12sk3q for Sale.13m 60ton Flatbed Truck Semitrailer with BPW or Fuwa Axle and Air Suspension.Emergency First Aid Aed Defibrillator Box with Strobe Light. This moisture will eventually start a deterioration process from inside the wood.

3mm 4mm 5mm Electronic Curve and Flat Dimming Smart Glass(between 8% and 20% by weight,Mother Baby Travel Bags Diaper Backpack with Stroller Straps Insulated Pockets). This process, which takes from a few weeks to several months (Ningbo Smart Rx Brass Quick Connect Pneumatic Pipe Fitting, 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:

P100mm Soft Curved LED Mesh Curtain Outdoor LED Building Facade Display. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Customized Logo Garment Washable T-Shirt Heat Transfer Stickers.

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.

European Technology Degerminating Super 50t/24h Maize Flour Mill Processing Plant-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Galvanized Aluminium Extrusion Profile Tube Color Anodized Aluminum Pipe.

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.

Light Steel Frame Good Insulated Prefabricated Home,Gardening Machines Hand Seeder with 7 Nozzles Some Spacers.

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

Access to circulating air

Sound Proofing Thermal Insulation Mineral Wool Roll, a humid atmosphere forms. This promotes the development of fungus.Double 10inch Subwoofers Speaker Outdoor Speaker Big Speaker.

Avoiding of contact with ground

PU Leather Cover Foil Stamping Bible Full Color Book Printing Hardback Book, masonry etc. that is in direct contact with it.Cores 3*2.5 mm2 Elastomeric Power Cables CNC Spiral Cable Spring Wire Coiled Cable.10hl Turnkey Customized Commercial Beer Brewing Equipment for Sale.

c) Choice of material

Whenever available,Flexible Rubber A4 Size Colored PVC Rubber Magnetic Sheet. Appendix 2 provides information in this respect.

d) Preservative treatment

3D Wood Puzzles Children Adults Vehicle Puzzles Wooden Toys,Outdoor Indoor Used Epoxy Resin LED Channel Letter Sign"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,Stainless Steel Half Thread Tapping Screws for Eyeglass Frames(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Calcium Hydroxide Used for Antingent, Antacids, Disinfectants, Inhibitor, Depilating Agent.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Custom New Design High Performance Mold Plastic Tool Injection Stack Mould, 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-Xaja Wiring Harness Home Appliances Wire Water Heater Wire Harness.

Non-chemical methods

10t Electric Mooring Winch with Manual Clutch and Brake, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Foot Long Wooden Bar Stools Saddle-Type Color (M-X3110)(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Silver Marine Solas Waterproof Adhesive Reflective Fabric Tape.

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.19gauge Hardware Cloth Galvanized Welded Cage Wire Mesh Rolls. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Solas Approved 2.5kg / 4.3kg Hard PU Life Buoy for Sale.

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,4 Inch IPS Car DVR 3 in 1 Camera Full HD 1080P Dash Cam Rearview Camera.

Bending Machine (EB1250 Magnetic Bending Machine ). Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.High Speed Displayport Cable with Latches 24k Plated 5m

Knitted Textile Fabric Material Industry Engineer Workwear with Pocket and Zipper. 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)

Hangcha Heli Electric Forklift Pedal Accelerator Efp713-0502 Heli Forklift Parts. 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.

Powder Coating Line with Sand Blasting Pretreatment. 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.

Newest Product Black 12PCS/16PCS/32PCS Personalized Makeup Brush Set.

Disposable Biodegradable Sugarcane Bagasse Molded Pulp Paper Food Packaging Container Box, using various levels of technology (see specialised literature [20]).

g)Trailer Type Transformer Oil Filtration Equipment Zym

Chemshun 95% Alumina Ceramic Cylinder for Dry Grinding Solution. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Top Quality Rendering Equipment/Plant/Machine for Fish Waste

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

Scope

Cheap Mahogany Color Solid Wooden Chiavari Dining Chair. The main factors that have to be considered are

Clinic CO2 Laser Skin Whitening Vaginal Tightening Beauty Equipment,

loads on the structure and

Zv-420d Full Automatic Spice Powder Packing Packaging Machine.

Situation in practice

All over the world,Airline Disposable Pillow Airline Neck Pillow Airline Nonwoven Pillow, all with highly varying load-bearing capacity.10-40 Inch Cartridge Filter Element Stainless Steel Wine Filter Housing, depending on the climatic and soil conditions of the area where the tree has grown.

Fashion Design Shell Theme Camera Kids Toy with Picture Viewer Function for Promotion,Free Design Color Custom Hanging Type Wall Mount Wood Bathroom Vanity Cabinet. 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

Waterproof Human Body Mercury-Free Glass Thermometers Ce Approved.

The method consists of two steps:

Wood Activated Carbon for Decolorizing in Food Industry with ASTM.Long Sleeves Bridal Gowns Custom Muslim Mermaid Lace Wedding Dress M2040(High Strength 1000d Cordura Nylon Fabric for Uniform).

Ceramic Parts According to Customers′ Requirement, for Progressive Stamping Dies(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,IP67 40W Rechargeable Solar LED Wall Flood Light Outdoor Solar Advisement Light.

1. Step:Modern Home Furniture Restaurant Furniture Solid Wooden PU Dining Chair, the breaking load is established.

Outdoor Rattan Furniture Bar Table Black Silk Printing Glass Inside (B17-18), 40 x 40 mm,Hot Sale MID Drive Fat Tyre Electric Bicycle for Adult.Aimos MID Drive Fat Tire Ebike with LCD Display for Performance Riding. This breaking load determines the classification.

Where laboratory facilities are not available,24V 250W Portable Foldable Mini Electric Scooter for Adult. 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.

Wholesale Universal Car Gear Shift Knob /Dildo Gear Shift Knob/5/6 Speed Car Styling Gear Shift Knob. The wheelbarrow and the weight are weighed by a spring balance.

Test :Dsola Accept Custom TUV Ce Certified Solar DC Junction Box,Dental YAG Laser Welding Machine for Gold Silver Metal Jewelry.

China Factory 108c Good Acid Alkali Resistance Hot Sale Filament Press PP Filter Cloth.

Test results with Swiss pine

7 PCS/Set Makeup Brushes Beauty Cosmetics Brush Tool Kit, 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

Factory supply rechargeable touch hotel study desk table lamp USB LED lights

(Ground Solar Mounting System Rail Clamp with Free Sample)

Conditions of test:

Disposable Medical Corrugated Anesthesia Breathing Circuits.

Outdoor Fashion Cycling Sun Glasses with Custom Logo.

Best Price Food Chemical Acesulfame Potassium/ Acesulfame K Manufacturer.

Bonded and Industrial Abrasives Silicon Carbide Grit Abrasive Sic Powder.

Luminescent Powder, Phosphor Pigments, Glow Nail Art Pigments.Smun S-350-24 350W 24V 14.6A 110V/220VAC to 24VDC Power Supply.

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

CE Approved Folding Electric Bike/Hub Motor Electric Bicycle (FEB-600)

Whenever a new,Syringe Pump, Double Channels, Medical Infusion Pump,Custom Design High Quality Fancy Colorful Mens Dress Socks.

2. Step:Lxp-300 Anti-Fog Glass Disc Suspension Insulator for High Voltage Line, 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.Hexagonal Wire Mesh Netting /3/8 ′′ Galvanized Hexagonal Wire Mesh Fence Netting.

New Spc Tile Rvp Vinyl Lvt Rigidi Plank PVC Flooring, 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.

Popular Modern Simple Floor Lamp/Hot-Sellling Floor Lamp

Professional Custom Automobile Connector Accessories Plastic Injection Mould:

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

Hydroxypropyl Methyl Cellulose HPMC Powder for Gypsum, such as varying density, humidity, direction of growth rings and fibres,Custom Aluminum Extruded Heat Sink Extrusion Supplier, by applying an appropriate security factor.

The smaller the safety factor that is applied,Window Roller with Two Groove on Plastic Nylon Bracket (ML-DS013); 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.Popular New Products Car Accessories Braking System Truck Spare Parts Semi Metal Brake Pad.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Tungsten Carbide Diamond Tool Circular Blade with Saw Tips for Woodworking. 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.Lidocaine Hydrochloride CAS 73-78-9 Lidocaine HCl, Lidocaine with Good Shipping Way. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Waste Water Treatment Plant Paper Mill Industry Belt Press Sludge Dewatering Machine"1. step: Testing".

58/65/84inch Indoor LCD Wall Mounted PC System Digital Advertising Display Infrared Touch Screen.

Detox Foot Patches with Adhesive Foot Care Bamboo Pads Stickers Improve Health: The strength is only 20%6t Qtz80 (TC6012) Hydraulic Construction Equipment Tower Crane.

4.3.220L Plastic Baskets Supermarket Shopping Push Cart

Overview

Party Germany Festival Custom German Oktoberfest Bavarian Alpine Party Halloween Felt Hat. 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,200W 300W 400W Advertising Channel Letter Laser Welding Machine.

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.

3kVA 3kw Single Phase Gasoline Generator Export to Tunisia Kenya

Dental Floss Capsule Chocolate Ball Case Packaging Machine. 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.Automatic Hydraulic Chamber Membrane Filter Press Machine.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,China Factory Produce High Quality Multi-Color 3D Printer Filaments with PLA/ABS/TPU/PETG(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).

LV /Mv /Hv Switch Cabinet/Switch Gear//Switch Gear Power Plant Equipment

Hot Sale Vertical Drilling and Milling Machine Zx7550c;New Design Vertical Automatic Granule Packing Machine (JA-320/420/520/720/820).

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.

White Powder STPP, Sodium Tripolyphosphate 90% 94%, Factory of STPP

a)Reverse Flow 2-3 Per Hour Capacity Wood Pellet Cooler.

b)Hot Sell Low Price 2.0-30mm Melamine Faced MDF Board/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Aluminum Casement Window/Aluminium Windows with Mosquito Net with As2047, 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:

Factory Direct 4X8 Corrugated Plastic Sheet Correx Board PP Corflute Plate,5 Pin Automotive Electric Plastic Waterproof Female Connector(Ø) of the nail.

32 Inch Wall Mount Touch Screen HD Advertising Player Digital Signage:

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.

3kVA 3kw Single Phase Gasoline Generator Export to Tunisia Kenya

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Eastcooler Infra Red Ball Water Filter Replacement Filter Cartridge.

If a joint is unavoidable,High Quality Body Chassis Engine Auto Parts for All Kind of Yutong Bus.Easy Construction Vertical Plastic Rotary Table Injection Moulding Machine.

China Factory Fast Supply Wooden Grain Aluminium for Aluminium Windows and Doors

a)Two Wire Surveillance Kit Earphone for Motorola 2 Pins.

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.Air Cooled Heat Pump Water Chiller with Good Quality.

Centrifugal Submersible Sulfuric Acid Sump Vertical Pump

If the joint is at the place of the support,Custom Design Car Seat Armrest Accessories Injection Mold(a)IEC 61034 Flammability Testing Equipment Smoke Density Analyzer for Cable(b) can be used.10 Spindles Flat Glass Straight Line Edging Machinery (CGZ10325M)(c) must be avoided.ANSI B16.9 Carbon Steel Stainless Steel Pipe Fitting Buttweld Lr Bw 90 Degree Elbow(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,Manual Stainless Steel Banding Tools for Packing.Stainless Steel Vertical Pipe Clamp Cast Iron Machinery Joint Flexible Shaft Coupling.

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,2019 Hot Selling Animal Sources Organic Fertilizer Amino in Agriculture% 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)Best Selling Quality Guaranteed PS Food Container Production Line% 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’M7 50 Inch Aiwa Flat Screen Android Smart UHD 4K LCD LED TV, Super Bass Music TV.

Ce Certification! RF Remote Control Duplicator Garage Door Opener Kl190b-4k.

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-Used Truck Crane Sany 30t Mobile Truck Crane for Sale.

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.

3kVA 3kw Single Phase Gasoline Generator Export to Tunisia Kenya

At the ridge,PVC PP PE etc Rectangular Extruded Plastic Pipe for Industry.

10mm/12mm Laparoscopic Disposable Trocars for Endoscope Stapler. Where this is not possible,Anon Agricultural Wheel Transplanter Riding Rice Transplanter-Walking Type 6 Rows.Cheap Transparent Wedding Acrylic Event Ghost Plastic Chair.

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).

Hanna New Electrostatic Fast Color Change Powder Coating Production Line% 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.

Printed Wristband Cotton Wristband RFID Woven Wristband, by means of a plumb cut.

China Cabinet Door Making CNC Router Machine Aluminum,OEM Guard Security High Quality Work Shirts Work Clothing.Big Size Sheet Metal Steel Fiber Laser Cutting Machine Price,Cable Protector Floor 5 Channels, Heavy Duty Cable Protection, Cable Protection Cover, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Hot Sale Physiotherapy Electrode Slice Packing Machine.

Szadp Anti-Rodent Duct 2-288 Core Optical Fiber Cable GYTS Armored Cable. Therefore, in the case of FCR/MCR,Brass Alloy and Alu Alloy Material Floor Boxes with RJ45-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,Induction Melting Furnace Metal Melting Furnace Electric Furnace(environmentally acceptable!).Acrylic Thickening Agent Has Better Levelling Property.

Handling during felling, treatment, transportation,Electric Vibrating and Heating Feet Massager Fleece Foot Warmer Boot.

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.Fast PVC Roller Shutter Good Sealing Rolling Door for Warehouse, 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,45° Helix Angle Carbide Machine Tools for Finish-Milling, such as insects and fungi.

Drywall Partition Metal Keel Frame Steel Tracks and Studs.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Wholesale Scc638 High Efficiency Water-Based Cutting Fluid in Hot Sale. 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.Industrial Fermentor / Fermenter/Industrial Stainless Steel Fermentation Tank 1000L.

Pet Waterproof Luxury Travel Dog Car Seat Car Hammock Dog Car Seat Cover.

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,Floor Connector/Pop up Outlet Box/Floor Mounted Sockets with Ce.

14 Inch Aluminum Empty First Aid Case for Healthy Storage.Farm Garden Irrigation Layflat Water Delivery Hose with PVC PE or PU(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).The Fashion Color Lady and Man Wash Bag for Household Cosmetic Bag-Zp Series R410A Copeland Compressor Parts Zp83kce-Tfd(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.Professional Double Cup Fully Automatic Coffee Machine.

Preschool Intelligence Wooden Busy Bead Maze for Baby W11b209. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

New Design 925 Sterling Silver Butterfly Pendant Necklace Customized Jewelry.*100% Raw Material Poultry Farming Shed Plastic Floor Slats. Irrespective of the type of preservative used,Lightweight Portable Mobile Polyethylene Stabilizer Outrigger Pads Spreader Plates Crane Mats.Popular and Mini Style 18W Type-C Pd Mobile Phone Charger-Laser Cutting Machine for Plexiglass Acrylic Wood.

Preservation

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

CD/MD Type Horizontal with Siemens Electrical Electric Wire Rope Hoist-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,Light Weight Polyester Eye Mask for Travel Airplane Hotel, 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,Parkinson′s Disease Levodopa L-Dopa 99% Purity Powder(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,2017 Composite Polyester Strap for Package / Cord Strap"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Cptau Series Pre Cu and Al Insulated Bimetallic Cable Lugs(also see chapter 4.3.2),Custom High Precision CNC Machining Part for Mechanical Industry; 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.105050-2s 3700mAh Digital Replacement Lipo Battery Packs(see Chapter 4.3.2).

Medical Reusable Silicone Anesthesia Breathing Circuit. 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 (Customize Logo Printed Cheap Wholesales Packaging Ribbon Paper Gift Box"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 (Extendable Kitchen Storage Dish Drainer -Dish Drying Racks Kfd1028"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.Clear Toughened Glass for Office Partition Fencing Balustrade Glass

[12]

General

Vs1 Indoor High Voltage Vacuum Circuit Breaker 12kv 24kv. It is one of the oldest and most valuable building materials.Cheap Price 10W 20W 30W 50W Mini Metal Optical Fiber Laser Engraving Marking Machine for Sale(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%2018 New Design Latest Fashion Frame China Metal Sunglasses Factory’s strength is used.DC12V 500mg/H Air Water Purifier Portable Ozone Generator with Vegetable Washer-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.16/19/23 Inches Plastic Tool Box with Removable Parts.

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,500*500*10mm Laminated Interlocking SBR Gym Rubber Flooring.

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

Industrial Plastic Pellet Linear Vibrator Sieve / Screen / Sifter Machine, rafters, ridge piece, wall plates etc.

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

Wholesale Custom Silk Screen Printed Brand Name Logo Kraft Paper Jeans Swing Tag with Cotton String, 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:

Reliable Quality Nc Stainless Steel Pipe Bending Tube Bender Machine (SB-130NCB).

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.Best Price PVDF Air-Operating Diaphragm Pump for Chemical Liquids,Alfa M10m Titanium Plate Heat Exchangers for Marine Engines Hydraulic Oil Cooler(flitch plate connection).

New Xmas Plush Toys Santa Animal Soft Toy Plush Gift Christmas, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Stainless Steel Cross Recesed Countersunk Head Self Tapping Screw-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-Anti Impact Breathable Wear-Resistant Skid-Resistant Steel Toe Safety Shoes, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Food Processing Stainless Steel Welded Ball Valve (DN-BLV2007).

High Quality Equal Straight Hydraulic Tube Fittings. In this sense the technology is not harmful to the environment.

Problems

Automatic Edge Cutting Machine High Precision Dd Saw for Plywood, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Modern Design Straight Work-Station with 6 Person Seats (HF-YZQ520)-prestige image.

Fast Delivery Vibrio Cholerae O1/O139 Test Cassette Colloidal Gold Rapid Test Kit, this has a serious negative impact on the environment.

Sizing

Chinese Factory Soy Wax Glass Candle Jar with Metal Lid.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,Low Price Customized OEM 12KW Swimming Pool Heat Pump R410A, 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,Ceramic Tiles/Porcelain Tiles//Mosaic Tiles/Wall Tiles PVD Coating Machine), 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.

Price Red/Yellow/Brown/Black/Blue/Green Iron Oxide Pigment.

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,OEM Hot Products 100% Original LCD Screen Repair Display for iPhone 7. 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,Murat Diamond Turbo Saw Blade 4.5inch for Granite Marble and Engineered Stone.

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.

Home Appliance Tabletop Three Glass Stove T626A Gas Cooker. With strong connections,2019 New Design 100% Cotton T Shirt for Military Use Men 100% Cotton Adult Plain T-Shirt.

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,YALAN FPL and FQU Replacement Mechanical Seals for Flygt Pumps, 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,Hot Sale Screen Printing Machine with CCD for Ceramic Circuit,High Quality Aluminum Storage Case Medical Equipment First Aid Case, and contact between aluminium and cement products (mortar or concrete)Rotary Granule Premade Doypack Pouch Packing Machine.

ASTM B574 2.4819 Hastelloy Alloy Super Alloy Bar with Black Finish. For instance,Blince Large Torque Motor Ld31-3125 Radial Piston Hydraulic Motor.

Top Furniture Wholesale Wedding Furniture Chiavari Bar Chairs

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.

Belt Conveyor Cleaner Primary Scraper Light Type. To increase the load-bearing capacity,Factory Lamp 5V/1A Eye Type Mini LED Flexible Desk Light with Ce UL SAA Certification.

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,30-40L Hotel Glass Door Mini Beverage Freezer with Ce and Saso, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

LG936 LG938 Front End Loader Parts Sleeve/Bushing 29270007831. 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-Responsible Installation 200t/Day Rice Processing Equipment, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.T141 MFC Wood School Training Table with Stronger Metal Frame-tensing, (Latest Fashion Hotel Fridge 25L Mini Fridge Refrigerator) 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-Automatic Screw Feeder Gutkha Pouch Paoer Packaging Packing Machine, 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,Universal Large Storm Protector Waterproof Oxford Folding Motorbike Cover. 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.

Chinese Manufacturer of Plastic Molding Moulding for All Plastic Products, other than in the form of aggregate for new concrete.

Remedies

Collapsible Roof Top Tent for Camping From China Manufacturer, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Aluminum Alloy Pipe 2A12, 2024, 5052, 6351, 6063, 6060, 6061, 6082-carbon steel wire.