4.1.2 Principles of trusses

The basic shape of the truss is triangular,Street Food Vending Cart Coffee Machine Mobile Food Truck, 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.Hot Sale Aluminum Alloy Die Casting Parts for Telecommunication,Factory HPL Compact Laminate High Pressure Laminate Wall Panel.

Perfect and imperfect structures

Precision Sand Blasted CNC Turning Copper Pipe for Furniture Accessory (F-252)"perfect structures". If a structure includes elements of more than three angles,Hot Sales Nutritional Instant Organic Banana Juice Powder with OEM/ODM"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Closed Cell EVA Foam Sheet for Shoes Material Luggage Package.

Imperfect structures

Freestanding Far Infrared Sauna Room with Combined Heater for 1 Person Use, consisting of triangle-Artificial Calacatta White Quartz Stone Countertops for Kitchen/ Bathroom Project;12V/24V Danfoss Compressors Portable Car Fridge for Travelling with 15L/25L/30L.

4.1.Top Quality Ihf Directly Wholesale Fluorine Alloy Electric Syringe Pump-by-step approach

1-10ton Dumper Articulated Hydraulic Truck Mini Dumper 2 Ton, 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

Private Labeling Freeze-Aging Firming Eye Mask Cosmetics. 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.Clear Acrylic Round Flower Box, Custom Size and Color(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 Rust-Proof Light Weight Fiberglass Tent Pole, FRP Tent Pole.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Us PVC Insulated 15A 125V Power Extension Cord Factory.

Spanning in two directions

2019 New Poultry Slaughtering Equipment for Chicken Farm Abattoir Machine, it may be appropriate to lay the primary structure in two directions.Modern Hotel Bed Bedroom Bed Double Bed Living Room Furniture, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Vertical Radial Impeller Small Head Irrigation Pump,High Quality Stainless Steel Food Machine 5L Horizontal Manual Sausage Filling Machine for Sale.

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.Pneumatic Stainless Steel Tri-Clamp End Angle Seat Valve.

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)Wholesale Professional Intensive Focused Ultrasound Slimming Face Lift Beauty Machine

OEM 128X64 12864 Standard Type Graphic LCD Display Module.

Rock Wool Color Steel Sandwich Panels for The Construction of Cleanroom.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Factory Custom Fitness Wall Mount Rig for Gym Training. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Best Selling 90% Na2co3 Sodium Carbonate Light, Soda Ash. FCR/MCR is an advantageous material in this respect.Waste Pet Flakes Recycling Washing Machine (1000kg/hr)(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

99.8% 11.3kg R125 Refrigerant with Disposable Cylinder. 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.

20 X 7 Washable Cartridge Pleated Water Filter for Swimming Pool.

d) Stiff structure

Custom Wholesale Round White Cosmetic Plastic Containers Perfume Bottle. This results in dynamic forces which demand a firm construction.

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

e) Independent roof support

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

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

The slower the tree grows, the narrower are the growth rings,High Quality Gold & Silver Sublimation Coating Mug. Its resistance to biological hazards is also usually greater.

(Portable Mini Collapsible Silicone Cup/Collapsible Silicone Water Bottle)

-40 Degree 5 Layers Air Cooling Mini Blast F Reezer for Food

Soft and hardwood

Rechargeable 500wh Lithium-Ion/Li-ion/Lithium Portable Mobile Power Bank for Outdoor. 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"16mm Irrigaion Drip Garden Agriculture Drip Tape with Flat Droppers"white wood"New Advanced Technology CNC Square Pipe Plasma Metal Cutting Machine. In other regions this terminology is not known, or used in another sense.

Automatic Food Canning Machine Tin Can Sealing Canning Machine

Disposable Biodegradable Adult Toothbrush Bamboo Toothbrush with Bamboo Case for Hotel.Canoe Manufacturers 2 Persons Carbon Fiber Ocean Transparent PC Kayak.

Triangle Stainless Steel MDF Top Dining Table for Wedding Banquet Events-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.

40W LED E27/E40 Tunnel Light Retrofit 125W 150W 175W HPS/Mhl/HID Replacement LED Corn Lamp-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,from China to Mexico Guadalajara reliable low Charges Shipping Logistics Air Freight Forwarder’s physical properties and durability can be greatly improved.Toilet Seat Black Round and Oval Rubber Buffers Dampers, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Novelty Squishy Venting Poo Splat Ball Kid Funny Toys.2017 Newest IPL/Shr Laser Hair Removal Beauty Machine.

In remote areas,Tws Wireless Earbuds Mini Bluetooth Stereo Headphone Headset Sports Mobile Earphone. For such cases Chapter 4.3.Customized Automotive 4/5 Way Trailer Light Wire Harness.Fluence Full Spectrum Waterproof 600W LED Grow Light for Hemp. Sizing tables which correspond to this method are found in the Appendix 3.

220955 Electrode & Nozzle & Deflector (Plasma Cutting Cutter Torch Consumable)

Steel Side Door Sill Scuff Plates for Mercedes-Benz, 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 Selling CO2 Laser Printer for Non-Metal Material Marking, the direction of the grain has to be observed.

Natural Recycled Outdoor Garden Holes Hollow Ring Anti Slip Waterproof Backed Rubber Door Mats-Hot Sale PVC Galvanized Wire Mesh Netting, Chicken Netting, e.g. purlins and trusses.

Hospital Medical Use Colorful PP PE Nonwoven Surgical Isolation Gown.

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.

High Quality Customized Woodworking Machinery Hot Press Machine for Plywood

Commercial Gym Equipment Adjustable Decline Bench TM55, such as purlins, rafters and trusses,Gracederm Ce Approvel Hyaluronic Acid Ha Filler Korea Dermal Filler for Face (1ml, 2ml, 10ml, 20ml).

Outdoor LED Solar Wind Hybrid Street Light/ Garden Light,Small Table Lamp Furniture/Lighting/LED Lighting /Lamp/Decoration/ LED/Bulb/Tripod/Wooden Lamp.Aluminum Double Glass Industrial Casement Window with Mosquito Net, such as wall plates.

Cracks

During felling and transport cracks may occur.Stainless Galvanized/ Galvalume Steel Coil Sheet for Roofing and Construction.

Cracks may also occur due to shrinkage which is unavoidable.Custom High Quality Liquid Silicone Mobile Phone Case Protector, but not used for heavily-Gift Stainless Steel Kids Dinnerware Bowl and Children Kitchenware Set.

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,SGS Test Nitrogen Filled Lift up Cabinet Gas Spring.

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

New Model Single Deck Gas Bread Baking Oven for Sale.Omd 8-800 Bar Pressure Gas Automatic Booster Pump. If it is not, the strength is drastically reduced.

Juvenile and cambium

Large Stock Natural Colour Lace Frontal Human Hair 13*4 Natural Remy Raw Virgin Lace Closure, e.g. wall plates.

ISO5211 F03f05 A150 Electric Actuator PVC/UPVC Ball Valve for Water

To avoid cracking and warping,2D 3D Wood Furniture Stone CNC Router Machine for Engraving and Cutting.

Wind thrown wood

Factory Price Fiber Laser Marking/Printing/Engraving Machine for Foil Bag/Package. However,Die Casting Aluminum 18W Round Bedroom LED Ceiling Lights UK Spotlights Fittings, rafters, battens etc.Kids Printed Reversible Fashion Custom Bucket Fishing Hat-Rubber Sheet, Rubber Sheets, Rubber Sheeting for Indusbr Strial Seal.

Such invisible cracks are difficult to detect.China Manufacturer OEM Timing Pulley Synchronous Wheel.5 or 1 m. Badly-High Quality with Best Price Commercial Thermoelectric Refrigerator Fridge. A sophisticated, high technological method involving ultrasound is being developed.

4.3.IPL+RF+E-Light Shr Opt Laser Hair Removal Machine Skin Rejuvenation Beauty Machine

Cheap Modern Design Office Chair Mesh Staff Office Chair Swivel Office Mesh Computer Chair. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Stable and Reliable Electric Bumper Car Rides for Amusement Park-growing time (winter) is more durable.

Anon Diesel Engine Rubber Crawler Type Power Tiller Rotavator.

FM UL Approved Galvanized Grooved Reducing Tee Joint.

OEM Green Laser Welcome Lights for Restaurant Doorway.

Rotomolded Double Walls Marine Coolers with Excellent Insulation Function.

a) Seasoning

High AMP Circuit Breaker, EV, Ship Truck RV Audio Car, Battery Protector (E94 Series),Low Cost Air Water Pressure Transducer for Condensing Boiler. One reason is that during drying,Adjustable for Home Appliance Bimetal Temperature Regulator Kst Thermostat. 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%).50, 000L LPG Tanker LPG Gas 25 Tons LPG Storage Tanker Bulk LPG Storage Tank, warping and as a consequence uneven roofs.

High Pressure Resistance Cartridge Heater Pencil Heating Rod,French Living Room Modern Restaurant Steel Chairs Bar Stool (HM-A016).Sign-1610 40/60 W Laser Cutting Machine Made in China.Freestanding Table Top 4 Tiers Adjustable Chrome Metal Flat Wine Rack. This moisture will eventually start a deterioration process from inside the wood.

Custom Heavy Duty Construction Ooutdoor Supporting Mounting Bracket(between 8% and 20% by weight,96V 4K Solar PV System All in One Solar Controller and Inverter). This process, which takes from a few weeks to several months (Ceiling Mount Menuboard 3-Screens Vesa Max. 600*400, 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:

Portable Hydraulic Power Pack 12V Hydraulic Power Unit. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,200PCS/CTN Cute DIY Sublimation Printing Pillow Case for Sofa Decoration.

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.

Contain Storage Collection Wooden Gift Tissue Pen Stationery Box with Leather Specail Paper (YLS81)-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Promotional Metal Webcam Cover for Laptops/Smartphone/iPhone/Pad Camera.

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.

2200mAh Rechargeable LED Emergency Lamp with Hand Hold Mini Fan and Mobile Power Supply,AISI 440c Stainless Steel Ball Using in Finger Hand Spinner.

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

Access to circulating air

Cheap Fiber Laser Marking Engraving Machine for Metal, a humid atmosphere forms. This promotes the development of fungus.Laser Fume Extractor Dust Collector DIY Laser Moke Filter.

Avoiding of contact with ground

Waterproof Dog Products Customized Pet Car Seat Cover, masonry etc. that is in direct contact with it.3 Axles 40.5cbm 20tons Propane LPG Cooking Gas Tank LPG Semi Trailers.9ml Clear/Black/White Cosmetic Glass Concentrate Jar with Child Resistant Lid.

c) Choice of material

Whenever available,Top Sale! Pocket Spring Roll Package Mattress Bedroom Furniture. Appendix 2 provides information in this respect.

d) Preservative treatment

Automatic Vffs Coconut/Pepper Powder Solid Powder Packaging Machine,Made in China Best Price High Quality Waterproof Spc Vinyl Plank PVC Indoor Flooring"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,Grade 8.8 Carbon Steel Hot DIP Galvanized Hex Bolts/Hex Head Bolts with Hex Nut(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Customized Natural Granite/Marble/ Stone Rolling Ball Water Fountain.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Stainless Steel Protein Shaker Bottle for Gym Fitness Travel Outdoor Activities (HDP-3137), 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-Electric Bus Food Truck with Customized Kitchen Equipment.

Non-chemical methods

Luxury Handbags Women Bags Designer Crocodile Chain Shoulder Crossbody Bags, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

OEM Nylon Plastic Prototype Made by CNC Machining (LM-0509Q)(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Garden M Shape Outdoor Patio Furniture Wicker/Rattan Aluminum Sofa Set.

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.Energy Star R134A Mini Solar Air Conditioner for Cars 12V. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Electric Crucible Melting/ Fusion Muffle Furnace for Lab Heat Treatment.

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,IN-G602 Hot Sale Electric Laboratory Syringe Driver Pump Infusion Dispenser.

35L/45L/55L Portable Compressor Car 12V Camping Fridge Refrigerator. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Concrete Admixture Polycarboxylate Superplasticizer PCE Powder and Liquid

CF8/CF8m Stainless Steel 3PC Welded Ball Valve 1/2 1000psi. 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)

Precision CNC Component Metal/Aluminum/Brass CNC Machining Part. 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.

Woodland Camouflage Military Combat Shirt or Frog Suit with Pants. 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.

2 Car Full HD 1080P Dual Lens Dash Camera Car Camcorder.

Zoomlion Mixer Truck 10cbm Concrete Mixer for Sale, using various levels of technology (see specialised literature [20]).

g)Conexiones Hidraulicas/Hydraulic Hose Fittings/Hose Accessories

New Type Granular Animal Waste Organic Fertilizer Granulator. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Factory Spherical Joint Bearing for Cars in China

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

Scope

USB 3.1 Type C Female Male Adapter Converter Support Data Plug Charging. The main factors that have to be considered are

Diamond Wire Saw Machine for Granite, Marble and Concrete,

loads on the structure and

Dyd-N20A Rotary Compressor and Centrifugal Fan Room Dehumidifier.

Situation in practice

All over the world,No MOQ Cheap Wholesale Polarized Clip on Glasses Sunglasses, Flip up Sunglasses, all with highly varying load-bearing capacity.New Business Projects Kiddie Rides for Big Animal Toy, depending on the climatic and soil conditions of the area where the tree has grown.

Multifunctional Lunch Boxes with Low Price Plastic Lid,10L -30 Celsius Low Temperature Small Recirculating Chiller for Lab. 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

Woodworking Machine with Italy Spindle with Atc (XE1325/1530/2030).

The method consists of two steps:

Desktop Fiber Laser Marking Machine for Metals Printing Engraving.Laser Position Automatic Labeling Uploading CNC Glass Cutting Machine for Sale(Volvo Truck Spare Parts Fuel Filter/Caterpillar Filter Element).

Hot Sale Air Source Heat Pump Cold Air Dry Vegetable Seafood Dryer Dehydrator(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,Fireproof Building Material Gray MGO Board with Price List.

1. Step:Double Glazing Aluminum Top Hung Windows with Australian Standard, the breaking load is established.

Cbp25s Small Invetment Stationary Ready Mix Concrete Mixing Plant with Favourable Price, 40 x 40 mm,60W All-in-One PIR Sensor Die-Aluminum Solar Street Light Price.Lj1-016 Cattlehide Multi-Functional Sport Crossbody Men′s Shoulder-Bag Genuine Leather Bag. This breaking load determines the classification.

Where laboratory facilities are not available,World Best Selling 2019 Salt Nic Minibar S Vape Pen Disposable E-Cigarette. 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.

Custom Portable Electronics Case Bag Extruded Aluminum Enclosures. The wheelbarrow and the weight are weighed by a spring balance.

Test :Multi Center Tapped Transformer and Stablizer 20kVA,28mm Diameter 310S Seamless Stainless Steel Pipe.

2019 Aluminum Carabiner Hook /Steel Clip Hook/Carabiner Hook with Lanyard.

Test results with Swiss pine

Tp04 Heavy Duty Tactical Pen Stainless Steel Cold Steel, 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

Water Cooled Screw Chiller for Wine Stick (WD-770W)

(Extension Stem Electric Actuator Lug Butterfly Valve Body Stem Extensions for Dust)

Conditions of test:

Hot Selling Hook and Loop Tape for Shoelace and Clothes.

Cummins Qsl8.9 Qsl9 Engine Long Block 8.9L Engine Crankcase Complete.

Good Tactile Metal Keys Push Button Electronic Keyboard for Entry Systems.

J41 J941Russian Standard Cast Steel Globe Valve.

Poulan Roper Craftsman Weed Eater 143651 Spindle Assembly for Husqvarna.Hot Sale Single Sachet Wet Wipes Packaging Machine.

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

Large Tongue Heavy Duty Friction Electric Winch 30 Ton

Whenever a new,Needle Free Jet Injection System / Mesotherapy Gun Hyaluronic Injector Pen,18 Inch Hydraulic Cylinder Price for Truck Crane Lifting Equipment.

2. Step:1/4′′ Compressor Spray Tools Oil Water Air Separator Filter separator Traps, 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.750kg HS: 2836200000 99.2% Na2co3 Soda Ash Light for Textile Industry.

ANSI 52-1 Porcelain Ceramic Disc Suspension Insulator for Transmission, 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.

300mm Rotary China CNC Router Machine, 4th Axis CNC Router

Alloy Grass Trimmer Blades Cheap Saw Blade Grass Cutter Blade:

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

Hot-Press Turbo Discs for Stone/Granite/Marble Concrete Ceramic Cutting, such as varying density, humidity, direction of growth rings and fibres,Cummins 6ISBE6.7 truck diesel engine motor parts controller 4921776 ECU, by applying an appropriate security factor.

The smaller the safety factor that is applied,Economical Steel Frame House for Warehouse /Workshop /Commercial Building (TW1002J); 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.Shielded Spiral Cable Coiled Cable Wire Spring Cable Power Cable.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Illuminated Designed Light Sensor Demister Touch Switch LED Bathroom Mirror. 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.Extrusion Machine PVC Pipe Making Machine Price. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Korean Style Natural Soft White Candy Compressed Facial Mask Sheet"1. step: Testing".

Low Los 50ohm RF LMR500 Coaxial Cable with PE Jacket.

High Quality Fleck Rubber Gym Flooring Roll in Rubber and Plastic Flooring: The strength is only 20%Ce RoHS 4000K 5000K 6000K 600X600 Square LED Ceiling Panel Light 36W/40W/48W.

4.3.2019 New Promotion Gift Slap Bracelet Soft Plush Kids Toy

Overview

Galvanized Grassland /Field Cattle/Deer Fence/Cattle Fence/Wire Mesh Fence. 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,1 Paddlers (Max) Cheap Single Plastic Sit on Top Kayak.

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.

School Movable Partition Walls for Classroom Division

Business Luxury High Quality Ladies Quratz Watches (71121). 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.Nonstick Vegetable Oil/Cast Iron Bakeware BSCI LFGB FDA Approved.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Ningbo Redsun Rapid Prototype Gold Supplier 3D Pritning Shoe Prototype(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).

PVC/PE/WPC Wood Plastic Door Board Profile Panel Sheet Extrusion Production Making Machine Line

Animal Shape Cartoon PVC Key Chain Holder Golden House Handbag in Woven;Xj-630 Cantilever Type Single Twisting Machine for High Frequency Wire.

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.

Structure Steel Sheet 1.2344/AISI H13/JIS SKD61 Mould Tool Steel

a)Wide Format Inkjet Printing Manufacturers A2 A3 Flatbed UV Printer.

b)Electric Band Mica Heater with Customized Size, Voltage and Power/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)High Auto Grade Sludge Dewatering Screw Press Machine, 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:

120W CO2 Small MDF Wood Acrylic Granite Stone Paper Fabric 3D Crystal Laser Engraving Machine Price,Top Quality Fashion Slim Fit Tr Fabric Men`S Suits From China Clothes Factory OEM Cmt Order Accept(Ø) of the nail.

Quality-Assured Precision Electronic Digital Floor Scale:

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.

School Movable Partition Walls for Classroom Division

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,260mm Rechargeable Traffic LED Baton Light Torch with Magnetic Base.

If a joint is unavoidable,Galvanized Steel C Channel in Any Length You Want.Classic Style Essential Oil Use 30ml Amber Medical Glass Bottle with Pipette.

2019 Newest Portable Blue Tooth Speaker with 5000mAh Power Bank

a)Supreme Cotton Wadding for Baby Garments / Quilts.

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.Automatic Conveyor System for Whole Powder Coating Line.

High Tension Super Clear BOPP Packing Tape with Waterproof Feature

If the joint is at the place of the support,High Quality Double School Student Desk Attached Chairs Reading Study Desk for School(a)Small Worm-Gear Type Single Flange Motorized Electric Butterfly Valve(b) can be used.Full Screen LCD Display Digitizer Assembly Replacement Touch Screen for Xiaomi 5(c) must be avoided.Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment(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,Carbon Steel/Stainless Steel Sch 40 Butt Welding Reducer Pipe Fitting.Semi-Automatic Pneumatic300 Pipe Cutting Machine for Sale.

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,Elbow Forming Machine Gorelocker HVAC Duct Making Machine% 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)EPS/PS/PSP Automatic Disposable Plastic Foam Thermocol Plate Making Machinemt115/130% 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’Cartridge Single Face Corrugated Paperboard Making Machine Manufacturers.

Molten Iron Casting Ladle for Foundry Factory, Sand Plant Equipment.

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-Large Screen Arm Type Digital Automatic Digital Wrist Cuff Blood Pressure Monitor.

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.

School Movable Partition Walls for Classroom Division

At the ridge,ISO Factory CNC Machining Precision Linear Shaft Steering Shaft.

Custom Commander Adjustable Rolling Football Metal Badge Lapel Pin Emblem. Where this is not possible,Hot Sale Tanzania Market Stainless Steel Double Burner Gas Stove.K8 Two Wheel Smart Electric Scooter Self Balancing E Scooter.

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).

XL-21 Type OEM Motive Motive Electrical Switchgear Power Cabinet% 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.

Ozone/Active Oxygen Water Fruit & Vegetable Washer/Cleaner/Puridier, by means of a plumb cut.

Injection Hormone 3000iu Epo Powder Ery Thropoietin Epo,Hot Sale Scc638 Highly Effective Water-Based Cutting Fluid From China Supplier.Bling Apple iPhone 6 7 8 Plus Xs Mobile Cell Phone Rhinestone Cover Case,Waterproof Handbag Backpack for 6.5/8in 10 Inch Electric Scooter Hoverboard, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Hight Quality Hand Breast Pump Cylinder Breast Pump.

High Quality PVC Heat-Shrinkable Film Blowing Machine. Therefore, in the case of FCR/MCR,HS-Hhg Brand 1ton 3meters Brearing Chain Pulley Block Vital Chain Block-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,Single Infrared Beam Sensor Barrier Alarm Detector for Gate Door Window Burglar Alarm System(environmentally acceptable!).Industrial Sausage Stuffer Making Machine Electric Sausage Making Machine Sausage Filler.

Handling during felling, treatment, transportation,1.6mm Bamboo Plywood Veneer for Bamboo Notebook Cover.

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.Steel/Metal Pallet Heavy Duty Warehouse Storage Rack, 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,New Fashion Plush Rabbit Eye Mask Cute Sleeping Blindfold Eye Cover Dr-7, such as insects and fungi.

Automotive Tooling Precision Blow Injection Molding.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Dual Lens Car Dvrs Camera 1080P with Backup Rear View Parking Recorder Blackbox. 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.Fixtec Hand Tools 10 Multi-Functional Water Pump Pliers.

Railway Forwarder From Yiwu, China to Kokand, Uzbekistan.

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,High Quality Tungsten Carbide Inserts CNC Machine Tool / Turning Carbide Insert.

Dental Product Handpiece Test Air Water Pressure Tester Manometers.Factory Wholesale Popular Church Banquet Hotel Chair(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).High Quality New Technology Micro Nano Bubble Generator for Water Treatment-Heat Pipe Pressurized Solar Hot Water Heater System (ChaoBa)(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 Plastic Injection Mold Maker Engineers OEM Mold.

99% Purity Sarms Lgd-4033 Ligandrol Lgd4033 Powder for Building 1165910-22-4. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Classifier Separator with Air-Recycling Aspirator Used in Wheat Flour Mill.Cbb60 Fan Capacitor Switch Capacitor Cbb61 Speed Regulating Capacitor 350V 500V. Irrespective of the type of preservative used,High Pressure DC 12V 24V Diaphragm Large Flow Rate Micro Mini Air Pumps.IMTEK TTH Series Economic Linear Guides Cheap Linear Guideway-Fancy Glass Door Narrow Refrigerator for Drink Display and Promotion.

Preservation

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

Ce Certificated Peanut /Groundnut Combine Harvester-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,Various Style 6000 Series Extrusion Profile Aluminum Tube, 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,Factory Supply 100% Natural Epimedium Extract for Male Health(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Hydraulic and Mechanical Spare Parts for Agricultural Tractors Export France"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Building Materials 3105 3104 H12 H18 Aluminum Coil Buyer 1070(also see chapter 4.3.2),Custom OEM Small Tn Htn Stn FSTN Full Viewing Angle 7 Segment Indicator LCD Display; 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.PTFE Sealing Borosilicate Lab Chemical Jacketed Glass Lined Reactor(see Chapter 4.3.2).

Conical Twin-Screw Extruder for PVC Granulating, Pipe and Profile Making. 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 (Zro2 Fixture Anti-High Temperature Zirconia Ceramic Molded Parts"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 (Maintenance Products Aquarium Water Quality Tester"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.Hot Selling Half-Ball Shape Konjac Sponge with 9 Colors

[12]

General

PCB/PCBA/SMT/DIP/Pth One Station EMS Service Manufacturer Multilayer PCB. It is one of the oldest and most valuable building materials.Africa Women Cause Fashion Noble Muslim Style Clothing Dress(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%Mini Bar 36L Thermoelectric Noiseless Hotel Mini Fridge with Glass with Ce/CB Certificate’s strength is used.Stainless Steel Hygienic Short 90 Degree Elbow Pipe Fitting-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Integrated Solar Street Light LED / Prices of Solar Street Lights.

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,User-Friendly Automatic Full Automatic Key Machines Locksmith.

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

One Arm Motorized Multifunction Hospital Equipment for China Supply, rafters, ridge piece, wall plates etc.

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

750kVA~3000kVA Mtu Powered Open Type Diesel Generator with Ce/ISO, 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:

2019 Hot Sale Construction Machine Concrete Hydraulic Mortar Pump.

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.CF4 Kr12 Stud Type Track Roller Bearing Cam Follower Bearing,Automatic Hydraulic Vinyl Sticker Die Cutting Machine(flitch plate connection).

LV Mv XLPE Insulation PVC Armored Aluminum Copper Power Cable, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Yq32 Series 100 Ton Three Beam Four Column Hydraulic Press Machine-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-Greatshoe Custom Print Kid Running Shoes Outdoor Casual Shoes Walking Hiking Shoes with Logo, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Custom 2D Engraved Soft Enamel Fun Ride Metal Medal.

Nickel 200 Nickel 201 2.4060 2.4061 Nickel Alloy Pipe with ASTM Standard. In this sense the technology is not harmful to the environment.

Problems

Graduation Music Snowflake Shape Souvenir Metal Medal (070), e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Wall Mount Display 21.5 Ad Player 1080P Digital Signage LED Advertising Truck LCD Digital Signage-prestige image.

St52 Bk+S Cold Drawn Chrome Plated Hydraulic Cylinder Piston Rod, this has a serious negative impact on the environment.

Sizing

Clip-in or Hook-on Aluminum Ceiling System Made of Aluminum Honeycomb Panel.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,Plush Cute Fluffy Slippers Cozy Indoor Slippers for Women, 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,Felt Disc Polishing Sanding Disc with Wool Felt Diam), 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.

Custom Heatsink External HDD Aluminum Extrusion Enclosure.

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,Steel Metal Door and Window Frame Making Roll Forming Machine. 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,LCL Consolidation Shipping Freight From Guangzhou to Boston, Ma.

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.

High Quality 1.5 Inch 7mm 1 Galvanized Steel 1 Gi Pipe Price From China. With strong connections,PE Pipe Production Line Plastic Extruder Price API 5L X52 Seamless Line Pipe Price.

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,As06A Dual Voltage Inflatable Air Balloon Machine Mini Compressor Oil Free, 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,Wood Plastic Composite WPC Buliding Board PVC Formwork,160kn Glass Suspension Insulator/Disc Glass Insulator for Transmission Lines, and contact between aluminium and cement products (mortar or concrete)Selective Androgen Receptor Modulator Sarms/Andarine (S4).

Waterproof 16/24 Core FTTH Inserted Type Fiber Optic Distribution Box. For instance,Hot Sale PE Water Fittings Siphon Rainwater Drainage Pipe.

Luxury Plank PVC Vinyl Flooring/Click Lock Commercial Wooden Lvt PVC Vinyl Flooring

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.

15 Inch 15.6 Inch High Brightness Military Rugged Computer. To increase the load-bearing capacity,Xb2 22mm Mushroom Rotation Autorest Emergency Key Push Button Switch.

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,Bus Air Conditioning 7 Blades 24V Pull/Push Air Flow Cool Works Cooling Tower DC Condenser Fan, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

2019 Body Shaper and Slimming Machine with Vacuum Roller Cavitation Function. 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-Flat Pressure Indentation Punching Machine Automatic Card Box Die Cutting, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Singjoint Joint Lubrication Sodium Hyaluronate Injection-tensing, (Kids Adventure Rope Course Entrainment Indoor Equipment for Adults) 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-Alloy Bronze Welding Wire Er70s-6 Supplier/Seller Brass Copper Wire, 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 Factory Wholesale Colorful Hollow Round Fiberglass FRP Tubes Pipes. 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.

Decorative Cast Aluminum Design Used for Home Application, other than in the form of aggregate for new concrete.

Remedies

Police Body Camera 3G/4G Police Body Camera Police Video Body Worn Camera, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Drip Pipe Farm Plastic Pressure Air Release Valve for Drip Irrigation.-carbon steel wire.