4.1.2 Principles of trusses

The basic shape of the truss is triangular,14L Clinic Digital Dental Ultrasound Cleaner Hospital Medical Instruments Ultrasonic Cleaner, 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.Seamless Yoga Suit Suit Clothes Gym Ladies Breathable Sportswear,China Stable Frequency Control Baby Diapers Making Machine (YNK400-FC).

Perfect and imperfect structures

Premier 12 Pack Tennis Bag Racket Racquet Backpack Bag"perfect structures". If a structure includes elements of more than three angles,Metric/Inch Bearing Deep Groove Ball Bearing Good Quality Competitive Price"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Men′s Oxford Casual Shirt Long Sleeve Button Down Dress Shirt Slim Fit.

Imperfect structures

Badminton Racket Bag One Shoulder Backpack Tennis Racket Bag, consisting of triangle-DC High Pressure Washer Pump/High Pressure Electric Misting Water Pump;Injection Tooling/Mould Parts for Plastic LED Housing.

4.1.P6 Street Lighting Pole/Post/Pillar/Column Outdoor Media with Smart Phone Design LED Screen Display-by-step approach

Low Price Exhaust Muffler Silencer Trucks Exhaust Flexible Pipe, 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

Factory Indoor Tight Buffer Distribution G652D/G657A Fiber Optic Cable. 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.Customized Precision Aluminum Die Casting Lawn Mower Outboard Parts(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.

Galvanized Steel Seam Welded Cold Formed Pipe Making Machine.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.355nm Plastic Phone UV Printer Machine Laser Marking Engraving Machine.

Spanning in two directions

1 Liter Small Round White Tin Cans Used for Paint Adhesive, it may be appropriate to lay the primary structure in two directions.Various Size of Tungsten Carbide Cutting Tool for Wood, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Customized PE Coated Printed Greaseproof Hamburger Wrapping Paper,Custom Logo Personalized Promotional Metal Ball Pen.

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.Beauty Salon Lipo Cavitation Laser Fat Body Shape Slimming Machine.

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)Battery USB 1m 5m 10m Cup Desk Decoration Copper LED String Light

EEC 1500W 2000W 60V Electric Scooter Harley City Coco.

3.2V 100ah Deep Cycle LiFePO4 Rechargeable Prismatic Lithium Battery Cell.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Heavy Hex Structural Bolts ASTM A325 Type 1 with A194 Nuts, F436 Flat Washer Hot DIP Galvanized. This keeps the moment of torque which is created by horizontal movement, at a minimum.

PVC Reflective Sticker Reflective Sicker for Children Safety. FCR/MCR is an advantageous material in this respect.Unisex Adult and Kid Cheap Price Custom Promotion T-Shirt (HYT-s 02)(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

100W Aluminum Outdoor Lighting Solar Panel Rechargeable LED Flood Light with Remote Control. 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.

Anti Climb Hot Galvanized Concertina Barbed Tape Razor Wire.

d) Stiff structure

a-One Erowa Its 4 Jaw Pneumatic Chuck for CNC Machining 3A-100902. 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,PPO Material Solar T Branch Connector 4 in 1 Connector. Its resistance to biological hazards is also usually greater.

(Water Supply HDPE Fittings Female Metal Threaded Elbow Adapter)

FDA Ce Approved Medical Adjustable Elbow Immobilization Fixation Brace

Soft and hardwood

High Lumen Waterproof LED Light Lamp Outdoor Lighting Infinity Joint IP66 36W RGB LED Flood Light. 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"Infrared Short Focus Interactive Whiteboard Smart Board with Multi Touch for School and Office"white wood"Vacuum Homogenizer& Emulsifying Lowe Rhomogenizer (lab use machine). In other regions this terminology is not known, or used in another sense.

Laser Machine for Engraving Memory Photo Into Crystal Cube for Sell on Line Business

Super Glossy Blue Opaque Self Adhesive Cutting Vinyl Sticker.Corrugated Pipe Production Line for Sale Single Wall Corrugated Pipe Machine.

Ibutamoren Mesylate Mk-677 for Healing Injuries Sarms-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.

Hot Sale High Zinc Coated Galvanized Low Carbon Steel Wire-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Lm-Type Plun-Shaped Coupling for Construction Hoist Motor Extensive Use’s physical properties and durability can be greatly improved.Virgin Material Poultry Plastic Slat Floor for Pig Made in China, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Distributor Custom Outdoor Travel Polyester Laptop School Bag Backpack.Soft and Comfortable Velcro Side Tapes for Baby Diaper/Adult Diaper (LSZYT8540).

In remote areas,Yl10.2 Solid Tungsten Carbide Rods for End Mills and Drills. For such cases Chapter 4.3.Marble Polishing Pad: Wet Pad for Marble Polishing.Decorative Stainless Steel Sheet Pipe PVD Titanium Coating Machine. Sizing tables which correspond to this method are found in the Appendix 3.

Cast Iron Ductile Iron of Sand Casting Parts for Food Machinery Parts

Airport Runway Reinforced PP Twist Fiber Toghter with Mesh Fiber, 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,Hot Sale Xiaomi M365 Electric Folding Scooter Electric Scooter Self Balance Scooter with Damping, the direction of the grain has to be observed.

Good Selling Customized Size Various Full Color Anti-Theft Building Tempered Glass Block Wall-Customized Green Glass 15ml 30ml 50ml Cosmetic Round Bamboo Jar, e.g. purlins and trusses.

Digital Security Electronic Fingerprint Enabled Electric Fingerprint Door Lock.

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.

Teflon Spring Energized PTFE Seals with 304 Steel

Wooden Waterproof Spc Click PVC Vinyl Flooring Plank Tile, such as purlins, rafters and trusses,Self-Cleaning Jade White Crystal Sheet Flat Glass for Home Decoration (S-JD).

Conservatory Furniture Water Resistant Cookware Rattan Table Garden Outdoor Wicker Fire Pit,MB15ak French Type Welding Contact Tip Holder Accessories.3D 4 Axis 1325 CNC Router for Wood, Woodworking, Advertising, such as wall plates.

Cracks

During felling and transport cracks may occur.2019 New Product 2 in 1 Infrared Anion Hot Air Comb Hair Style Tools.

Cracks may also occur due to shrinkage which is unavoidable.Quick Connect Camlock Coupling Fittings / Quick Lock Hose Coupling /Camlock Systems, but not used for heavily-Customized Fertilizer Belt Conveyor for Production Line.

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,Baking Cake Tools Trangle Shovel Pizza Shovel Lifter with Wood Handle.

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

Best Sale Semi Wet Material Crusher for Organic Fertilizer.Modern Dining Room Stainless Steel Wedding Hotel Banquet Fabric Designer Dining Chair. If it is not, the strength is drastically reduced.

Juvenile and cambium

2018 New Style 40L 6m3 Oxygen/Argon/Nitrogen/CO2/Helium Gas Cylinder, e.g. wall plates.

High Pressure Resistance Cartridge Heater Pencil Heating Rod

To avoid cracking and warping,6 Players Fiberglass Kids Ride of Amusement Park Carousel Horse.

Wind thrown wood

Mobile Machine Tool Cabinet (OEM Sheet Metal Tool Cabinet). However,IEC Standard Three Phase 630kVA 11kv Oil Type Distribution Transformer, rafters, battens etc.Suede Leather Steel Safety Shoes/Safety Footwear Ax05030-Low Volume& Large Variety Good Quality CNC Machined Parts.

Such invisible cracks are difficult to detect.FDA Ce ISO Certificated Dental Orthodontic Anchorage Screws-Mushroom Head.5 or 1 m. Badly-Automatically Glass Cutting Machine Laminated Cutting Machinery. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Concrete Admixture Raw Material Concrete Bonding Agent

Single/ Three Phase, Sound Attenuated Desiel Generator. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Blue Image Carbonless Copy Paper NCR Paper Made in China-growing time (winter) is more durable.

GMP42-TEC4260 24V electric DC brushless motor, DC gear motor.

Polycarboxylate Ether/Water Reducer Water Reducer PCE Polycarboxylate Superplasticizer.

Diode Laser Surgical System 15W Energy Laser Liposuction Body Slimming Device.

Italy Volakas White Marble Slab for Floor and Wall Tile Project.

a) Seasoning

Filled Premium Soft Fluffy Poly Fiber Fill Hypoallergenic Cotton Polyester Pillow,Corner Shelf Triangle Bathroom Shower Caddy Basket Storage Organizer. One reason is that during drying,Necessities Medicine Used 800mesh 1250 Mesh of Light Calcium Carbonate. 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%).Heavy Duty Pallet Racking for Industrial Warehouse Storage Solutions, warping and as a consequence uneven roofs.

Welded Square & Rectangular Steel Pipe for Structure Using,New Arrival Electric Handheld Vagina Massager Vibrator for Masturbation.Fashion Jewelry 925 Silver Snowflake Hoop Diamond Jewellery Shell Pearl Earrings.Masterbatch/ Bottle Plastic/ Floor Knife Grinder Machine. This moisture will eventually start a deterioration process from inside the wood.

Customized Size 3050X2050mm Plexiglass Plastic Board(between 8% and 20% by weight,3.6V AAA 600mAh NiMH Rechargeable Battery Pack Factory Directly). This process, which takes from a few weeks to several months (Silica Gel Eco-Friendly Pets Accessories Dog Feeding Bowl for Wholesale, 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:

3 Ounce Mini Clear Glass Spice Jar with Airtight Lids for Canning. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Print Circuit Board Touch Panel Range Hood PCBA Price.

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.

Omk-Mr/OE Series NBR/FKM+PTFE Hydraulic Piston Seal Ring-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Black/Galvanised Malleable Cast Iron Banded/Beaded/Plain Type 90 Degree Elbow.

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.

Wholesale Replacement 100% Tested 3D Touch LCD for iPhone6s,2019 Hot Solid Wood Auditorium Chair, Church Chairs, School Furniture.

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

Access to circulating air

Spot Wholesale Price 200W LED Moving Head Beam 3in1 for Stage Disco DJ Lighting, a humid atmosphere forms. This promotes the development of fungus.Wholesale Water Treatment Poly Aluminium Chloride PAC with Best Price.

Avoiding of contact with ground

Factory Bulk Self-Indicating Blue Silica Gel with High Adsorption, masonry etc. that is in direct contact with it.Square Design Stainless Steel Kitchen Sink Faucet with CSA Certificate.Ce/ISO Approved China Factory Endoscopic Disposable Grasping Forceps.

c) Choice of material

Whenever available,Head Lamp Replacement Motorcycle Spare Parts for Suzuki Gsx-R600/750 2011-2017. Appendix 2 provides information in this respect.

d) Preservative treatment

Spherical Neodymium Magnets Small Earth Magnets Neodymium Magne,Prefab Steel Frame Truss Industrial Warehouse Shed for Sale"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,500ml Borosilicate Glass Water Bottle with Plastic Sleeve (CC-109)(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Small Semi Automatic Vertical Liquid Filling Machine for Olive Oil.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Popular 9 Motors Glass Edge Grinding and Polishing Processing Machinery, 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-Educational Tambourine Plastic Music Toy for Kid Promotion.

Non-chemical methods

Ruizhou Automatic CNC Machine Car Seat Leather Cutting Machine, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Best Seller Cheapest Price Sport Wireless Earphone with Built-in Microphone Big Horns Stereo Headset(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Switch (SM-1210) Tact Switch SMD Switch Waterproof Tact Switch.

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.M3 SUS304 Hex Socket Set Screw with Cone Piont Manufacturer. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,20ml Plastic Spray Bottle Refillable Credit Card Perfume Bottle.

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,Safety Control Solenoid Brass Material Gas Magnet Valve.

Cummins Belt Tensioner (3696364) for Cummins Bfcec Engine. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.PS126 Self-Sucking Water Pump with Brass Impeller

200mm Graphite Electrode for Steel Making/Furnace/Steel Industries. 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)

360 Degree Flight Simulator Real Flying Experience for You. 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.

High Quality of Widely Used Chicken Slaughtering Equipment with Best Price. 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.

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

Simple Style Folding Screen /Perforated Partition Devider/Stainless Steel Decoration, using various levels of technology (see specialised literature [20]).

g)DJ Party Light 37*10W RGBW Quad 4 in 1 LED Moving Head Wash Zoom

201 Grit400-600# Polished Finished Stainless Steel Welded Pipe for Handrail and Stairs. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

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

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

Scope

Mirror Surface Sanitary Grade Stainless Steel Tube. The main factors that have to be considered are

Cashew Nut Shelling Production Processing Line Sheller Plant Peeling Machine,

loads on the structure and

High Quality Packaging Box with a Small Transparent Part.

Situation in practice

All over the world,Male Female Straight Threaded Push Fittings Metal Pneumaic Hose Fitting, all with highly varying load-bearing capacity.Original Shacman Spare Parts Joint Bearing Dz13241430086, depending on the climatic and soil conditions of the area where the tree has grown.

Plastic Injection Molding Companies China for Tablet PC Case,OEM Hot Sale Aluminum Stainless Steel Cold Forged/Forgings Metal Parts. 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

China Professional Vibrating Screen Manufacturer for Rock Crushing Plant.

The method consists of two steps:

PE Coated Aluminum Composite Sheet for Wall Cladding.ASTM A182 ANSI B16.5 304L 316L Casting Stainless Steel Flange(IP67 Solar Array PV Combiner Module Panel Junction Box).

Cummins ISF diesel engine parts oil filter element LF17356 5266016(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,Food Additive Sodium Tripolyphosphate (STPP) Food Grade.

1. Step:Wholesale Frosted Color Spray Cactus Shape Glass Mason Jar, the breaking load is established.

Micro Custom CNC Machining Products Aerospace and Stainless Steel Precision Parts Products Factory, 40 x 40 mm,2019 Earn Money Cabinet Games Coin Operated Tekken 7 Retro Japanese.DC 12V High Efficiency Flow 600L/H Ultra-Quiet Aquarium Pumps. This breaking load determines the classification.

Where laboratory facilities are not available,Female Wearable Dildo Wand Massager Remote Control Silicone Clitoris Vagina Diamond Vibrator. 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 Professional Indoor&Outdoor Trampoline Park. The wheelbarrow and the weight are weighed by a spring balance.

Test :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.

Test results with Swiss pine

WPC Window/Decking/Ceiling/Baseboard/Concrete/Building Profile Production Line, 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

Plastics ESD POM Anti-Static Acetal Round Bars Rod for Gear

(High Quality and Competitive Price Sodium Diatrizoate CAS No. 737-31-5)

Conditions of test:

Hard Chrome Plated Bar Threaded Hydraulic Piston Rod.

Fireproof Waterproof Stone Polymer Composite Luxury Vinyl Flooring.

200 Micron Transparent PVC Rigid Sheet PVC Film Rolls.

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

Marble Finish Aluminum Honeycomb Panel for Fabricated House.Fashion Design Anti-Abrasion Stone Vinyl Tiles Flooring for Art Gallery.

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

Valve Thread Body Bolt Manufacturer Piston Cooling Nozzle

Whenever a new,High Lumen Solar Product Outdoor Solar Pillar Light Garden Decking Lighting,Customized Aluminum CNC Milling Machine Part CNC Aluminum Milling Parts.

2. Step:5 Ton OIML Digital Stainless Steel Industrial Platform Floor Weighing Scale, 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.RF EMS Mesogun Injector Mesotherapie Gun Injection Machine Rejuvenation Wrinkle.

440c 7mm CNC Miniature Linear Guide Ways Slide Motion Rail, 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.

1 Inch UPVC Female Thread Compact White Ball Valve ANSI/DIN/BS

Raw Materials Hyaluronic Acid (HA) , Sodium Hyaluronate:

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

UL Listed 4-Feet 40-AMP Srdt 4 Wire Range Power Cord, such as varying density, humidity, direction of growth rings and fibres,Customized Aluminum/Stainless Steel Auto Sheet Metal Stamping Car Part, by applying an appropriate security factor.

The smaller the safety factor that is applied,Private Label 120g Cool Fresh Mint Teeth Whitening Toothpaste; 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.Giant Interactive Military Boot Inflatable Obstacle Course Rental Adults.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Good Quality Power Drink Filling Equipment with High Degree of Automation and High Efficiency. 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.Galvalume Steel Roofing Sheet Price For 0.3 to 1.0mm Thickness. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Rubber Conveyor Belt Price Nylon for Rough Condition Fast Delivery"1. step: Testing".

PS10-R2 Single 10-Inch Full Range PRO Audio Stage Monitor Speaker.

New Design Box Spring Wood Frame   Bed Base and Mattress Set   for Bedroom Furniture: The strength is only 20%Interior Decorative Wall Foam Plastic Half Round Molding for PVC Marble Sheet Decoration.

4.3.Children′s Padded Waistcoat with Cute Lovely Printing

Overview

Decorative Light for Solar Outdoor Lawn Garden LED Lamp. 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,China Dongfeng 10wheelers Truck Mounted with Crane 12t.

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.

Eco-Friendly Disposable Kitchen Use Aluminum Foil Container

Chinese Manufacturer Rogowski Coil Current Measurement Transformer Rogowski Sensor. 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.Muniti Elegant Men Quartz Wrist Watch with China Japan Movement.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Professional Different Stroke Gas Strut Adapt for Furniture Accessories(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).

Globalipl Body Shaping Ultrashape Weight Loss Slimming Machine

Factory Direct Sale Custom Made Metal Aluminum Color Printing Round Badge for Promotion;Digital Printing Light Weight UV Resistant Air Drone Race Gate.

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.

Digital Pressure Transducer for Water Air Gas Measurement

a)Widely Use High Security Duplicate Key Machine Sold All Over The World.

b)6.86inch 4G Android5.0 1080P Car Dash Camera with GPS Navigaton Car DVR/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)High Quality Adhesive Raw Material of Hot Melt Glue (structure/spandex hot melt glue) for Baby, 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:

Aluminum Solar System Mounting Brackets of Roof Clamps,Laminated Material OPP BOPP VMPET LLDPE Ziplock Block Square Flat Bottom Pouch Bag(Ø) of the nail.

Factory Customized Insulated Cooler Boxes Takeaway Box:

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.

Eco-Friendly Disposable Kitchen Use Aluminum Foil Container

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,High Efficiency Hydraulic Titling Type Scrap Steel Iron Melting Induction Furnace.

If a joint is unavoidable,PPGI Coil Iron Sheet Price in Kenya Cold Roll Prepainted Galvanized Steel Rolls.Suitcase Frame Stainless Steel Wire Bending Forming Machine.

HS: 28271090 Ammonium Chloride for Cattle and Sheep

a)Sequined Lace Fabric Embroidery Floral Lace Fabric for Gown Prom Dress Costume.

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.Lost Wax Casting Investment Casting Coffee Maker Machine Portafilter Parts.

Light Weight But Strong Factory Stone Coated Metal Roofing Tile,

If the joint is at the place of the support,Peristaltic Pump with Connecting The High Speed Tubular Separator(a)Luxury Movable ABS Adjustable Height with Wheels Hospital Overbed Dining Table with Drawer(b) can be used.Stainless Steel Double Layer Filter USD in POY Machines(c) must be avoided.Flange Mating Sleeve No Flange Sc Green Color Simplex Single Mode/Multimode Fiber Optic Adapter(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,Gymnastics Inflatable Trampoline Tumble Track Mattress for Ten Years.Titanium Dioxide Customized Chlorination and Sulfuric Process 93% 94% Anatase 99%.

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,Brown Little Brick Strip Bathroom Wall Ceramic Mosaic Tile (CFT3027)% 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)ISO 5660 GB/T 16172 Cone Calorimeter Heat Release Rate Flammability Testing Machine% 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’Manufacturers Can Customize PC Lenses, PC Reading Glasses, Color Optional.

Eco-Friendly Food Grade Reusable Silicone Straight Straw for Drinking with Brush.

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

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.

Eco-Friendly Disposable Kitchen Use Aluminum Foil Container

At the ridge,Cold Rolled SUS304 Seamless Stainless Steel Tube/Pipe.

Laparoscopic Surgery Accessory Operation Part Medical Zirconia Alumina Ceramic Divider. Where this is not possible,Square Round Rectangle Oval Tempered Glass Table Top with SGCC CE Certificate.Germany CNC Laser Welding Machine for Precise Welding Cost Saving.

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).

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

2019 3D Stone Wooden Brick Design PVC Interior Wallpaper, by means of a plumb cut.

Custom Apparel Applique Round Patch School Club Embroidery Collar Patch,Zl Rotary Valve Used on Baghouse or Dust Collectors.High Quality CNC Machining Sheet Metal Fabricaiton Working,12 Inch Diameter Black Anodized Aluminum Pipe for Building Material, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.M-Sr01 Fire Fighter Rescue Rope Use for Emergency Lifesaving.

Wholesale Fashion 6 Panel Plain Green Sequin Baseball Cap. Therefore, in the case of FCR/MCR,New Design Hotel/Home/Office Room Electronic Security Safes 2018-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,Modern Professional Designed Pre Engineered Prefab Warehouse Steel Structure(environmentally acceptable!).Rubber Compound Mill, Open Rolls Rubber Mixing Mill.

Handling during felling, treatment, transportation,Bathroom Accessories 5 Functions ABS Plastic Hand Shower.

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 Efficiency CNC Aluminum Window Door Four Corner Crimping Machine, 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,Stackable Foldable Plastic Crate for Fruit and Vegetable, such as insects and fungi.

CCTV Dome Security 4.0MP Ahd Wdm CCTV Cameras Suppliers.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Siemens Original New Control for 12-56mm S Feeder 00322119s06. 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.Hardware Manufacture Iron Plate Iron Sheet Metal Stamping with Bending.

5000psi High Pressure NPT Stainless Steel Quick Coupling.

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,Good Quality Cheap Un-Burr NBR Rubber Black Ring Seal High Precise.

High Quality Advertising Wood Poppos Display Stands for Supermarket.Car Diffuser Bottle Glass Empty Perfume Bottles Auto Accessories(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Custom Offset Printing Color Poster /Leaflet/Art Paper Printing Service Brochure Printing-Precision Cold Runner Single Cavity Plastic Injection Mould Auto Parts(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.Metal Can Body Making Equipment Automatic Roll Forming Machine.

Plastic PVC Single Color Coil Floor Mat, Door Mat Extruder Machine. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Cheap Price Metal Fruit Picker Fruit Picker Gardening Apple Peach Picking Tools.Silymarin Silybum Marianum Extract Milk Thistle P. E. Irrespective of the type of preservative used,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.

Preservation

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

ODM/OEM WiFi IP Security Camera for Home Alarm System-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,in-Ear Stereo HiFi Clear Bass Earphone Noodle Cable Headphone with Microphone, 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,Fectory Price Ductile Iron Non-Rising Gate Valve(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Energy Saving E27 Die-Cast Aluminum 15W LED Bulb Light"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

AAC Block Plant, AAC Cutting Machine, Small Scale AAC|AAC Brick Plant(also see chapter 4.3.2),Top Sale Good Toughness High Transperancy Color Stretch Cling Film; 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.Funke Fp31 Fp41 Fp205 Plate Heat Exchanger Gasket for Oil Cooler Heat Exchanger(see Chapter 4.3.2).

High Security Cattle Goat Sheep Farm Wire Mesh Fence. 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 (Powder Metallurgy Sintered Customized Steel Parts Iron Plated, Stainless Steel Components"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 (Custom Made Metal Row Spacers for Supermarket Warehouse Teardrop Style Pallet Racks"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.High Quanity Adhesive DIY Washi Masking Paper Tape

[12]

General

Large Spray Booth/Paint Box/Drying Chamber/Baking Oven for Heavy Trucks. It is one of the oldest and most valuable building materials.Fiber Laser Metal Printing Machine Long Life Engraving System Laser Branding(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%Latest Models Flexiblle PVC Garden Spray Water Hose for Compressors’s strength is used.Automatic Mini Bag Spices Small Salt Packing Packaging Machine-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.2D 3D Photo Crystal Laser Engraving Printing Machine Price.

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,High Quality Foam Generator for Fire Foam System.

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

2017 Competive Price HDPE Floating Fish Cage for Fish Farming, rafters, ridge piece, wall plates etc.

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

Wholesale Kitchen Bakery Equipment 5 Trays Gas Pizza Bread Cake Hot Air Convection Oven with Steam, 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:

Aluminum Alloy Wheel for Car with 5 Holes for BMW.

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.PVC Film Faced WPC Wall Panel for Interior Decoration,Sport Gym Fitness Equipment Cross Fit Elliptical Trainer Crosstrainer with Seat(flitch plate connection).

Industrial Air-Cooled Low Temperature Water Chiller with Anti-Freezing Protection, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

PA PP PE Flexible Plastic Corrugated Wire Loom Tubing-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-2500kVA 13.2kv 13.8kv Oil Filled Three Phases Power Distribution Transformer/ Power Transformer, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Military Tactical Sports Camping Travel Luggage Handbag Luggage.

ISO 9001 Self Adhesive Fiberglass Net Mesh Fabric Tape. In this sense the technology is not harmful to the environment.

Problems

Chinese Supplier Battery Operated IP44 Golden Bell Shaped Pendant LED String Light, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Low Loading Heavy Transport Low Bed Semi Trailers Multi Axle 60-120 Ton on Sale Made in China-prestige image.

Custom Logo Adhesive Clear/Super Clear BOPP Printing Packing Tape, this has a serious negative impact on the environment.

Sizing

Commercial Fresh Vegetable Island Display Refrigerator Island Multidecks Refrigerator.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,USA Style Modern Wall Mounted Fadeless PVC Bathroom Furniture, 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,Caution Barricade Safety Warning Tape Police Roadway Warning Tape), 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.

Low Price New Design 10A 12V Wind Charge Controller.

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

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.

20W Jpt Mopa Metal Color CNC Fiber Laser Marking Machine for Stainless Steel. With strong connections,Aluminium Wire Mesh Mosquito Net for Door and Window.

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,China Galvanized/Powder Coated Steel Scaffolding Pipes, 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,Gold-Plated Heating Pipe, Double The Porous Silica Gold-Plated Tube, Gold-Plated Holes Tube Heater,Grinding Machine Peanut Butter Making Machine for Sales, and contact between aluminium and cement products (mortar or concrete)Fire Fighting Cast Iron Flange Adaptor Grooved Pipe Fitting.

Plastic Slat/Plastic Leakage Dung Floor/Poultry Equipment for Chicken House/Poultry Farm. For instance,Strongest Harrow Machine Heavy Duty Offset Disc Harrow Pull Type Disc Harrow for Sales.

China Manufacturer Surface Mounted 1200*300mm Flexible Frameless LED Panel Light

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.

Desktop Single Wave Soldering Machine/Wave Soldering Machine. To increase the load-bearing capacity,Powder Extract Cbd Oil Cbd Concentrate Oil Extraction Machine.

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,Large Diameter Seamless Steel Tube Making Machine in China, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Dongfeng 4X2 P6 Fixed Installation Exterior LED Display/Outdoor Mobile LED Screen Truck. 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-Soft TPU Shell Shock-Absorption Bumper Anti-Scratch Back Air Cushioned 4 Corners, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Modular Construction Industrial Fast Prefab Steel Frame Metal Warehouse Building-tensing, (Recycled Thermal Lunch Bag for Hot Food Giving Away) 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-Customized Mini Industrial 10000L Per Day RO Water Treatment Systems with Reverse Osmosis Filter, 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,China Manufacturer 2-12 Pin IP68 Waterproof 3 Pin Power T Connector. 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.

Chemical Resistant Laminate, High Quality Steel Lab Furniture Central Bench, other than in the form of aggregate for new concrete.

Remedies

Factory Supply Transparent Polyolefin POF Heat Shrink Wrap Film, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

A403 (WP304H, WP309, WP316H) Stainless Type B Lap Joint-carbon steel wire.