4.1.2 Principles of trusses

The basic shape of the truss is triangular,Clear Acrylic Round Flower Box, Custom Size and Color, 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.China Rust-Proof Light Weight Fiberglass Tent Pole, FRP Tent Pole,Us PVC Insulated 15A 125V Power Extension Cord Factory.

Perfect and imperfect structures

2019 New Poultry Slaughtering Equipment for Chicken Farm Abattoir Machine"perfect structures". If a structure includes elements of more than three angles,Modern Hotel Bed Bedroom Bed Double Bed Living Room Furniture"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Vertical Radial Impeller Small Head Irrigation Pump.

Imperfect structures

High Quality Stainless Steel Food Machine 5L Horizontal Manual Sausage Filling Machine for Sale, consisting of triangle-Fashion Pearl Cat Pendant Fashion 925 Silver Necklace;Dia8.0 Tungsten Carbide Reamer Through Hole H7 Spiral Reamer.

4.1.Disposable PVC EVA Anesthesia Ventilator Breathing Circuit-by-step approach

2019 Best Sale 125cc Adults 4 Wheeler Petrol Power Racing Quad Camouflage, 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

Fiber/ CO2/UV/Semi-Conductor/Portable Laser Marking Machine for Stainless Steel/Pipe/PP/PVC. 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.Facial Skin Care Pore Cleaner Blackhead Remover Vacuum(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.

Prefab Steel Structure Construction for Industrial Buildings.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Pneumatic Stainless Steel Tri-Clamp End Angle Seat Valve.

Spanning in two directions

Wholesale Professional Intensive Focused Ultrasound Slimming Face Lift Beauty Machine, it may be appropriate to lay the primary structure in two directions.OEM 128X64 12864 Standard Type Graphic LCD Display Module, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Rock Wool Color Steel Sandwich Panels for The Construction of Cleanroom,Promotional Reusable Foldable PP Non Woven Shopping Bag.

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.1080P Waterproof Police Video Body Worn Camera with 32g GPS.

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)Custom Australia Steel Fabricating Waste Containers for Sale

Low Price High Effect 1/4′′-2′′ Hydraulic Hose Crimping Tool.

Safety Work Protection Leather Footwear with Steel Toe/Safety Shoes.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Low Price Anti Rust Vci Paper for Automotive Spare Part (SGS, RoHS, Volkswagon Certificated). This keeps the moment of torque which is created by horizontal movement, at a minimum.

Modular Line Array Column Speaker Actpro Audio Professional Loudspeaker. FCR/MCR is an advantageous material in this respect.High Quality Gold & Silver Sublimation Coating Mug(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Portable Mini Collapsible Silicone Cup/Collapsible Silicone Water Bottle. 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.

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

d) Stiff structure

Rechargeable 500wh Lithium-Ion/Li-ion/Lithium Portable Mobile Power Bank for Outdoor. 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,Novelty Squishy Venting Poo Splat Ball Kid Funny Toys. Its resistance to biological hazards is also usually greater.

(2017 Newest IPL/Shr Laser Hair Removal Beauty Machine)

Tws Wireless Earbuds Mini Bluetooth Stereo Headphone Headset Sports Mobile Earphone

Soft and hardwood

Customized Automotive 4/5 Way Trailer Light Wire Harness. 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"Fluence Full Spectrum Waterproof 600W LED Grow Light for Hemp"white wood"220955 Electrode & Nozzle & Deflector (Plasma Cutting Cutter Torch Consumable). In other regions this terminology is not known, or used in another sense.

Steel Side Door Sill Scuff Plates for Mercedes-Benz

Hot Selling CO2 Laser Printer for Non-Metal Material Marking.Natural Recycled Outdoor Garden Holes Hollow Ring Anti Slip Waterproof Backed Rubber Door Mats.

Hot Sale PVC Galvanized Wire Mesh Netting, Chicken Netting-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.

Hospital Medical Use Colorful PP PE Nonwoven Surgical Isolation Gown-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,High Quality Customized Woodworking Machinery Hot Press Machine for Plywood’s physical properties and durability can be greatly improved.Commercial Gym Equipment Adjustable Decline Bench TM55, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,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.

In remote areas,Small Table Lamp Furniture/Lighting/LED Lighting /Lamp/Decoration/ LED/Bulb/Tripod/Wooden Lamp. For such cases Chapter 4.3.Aluminum Double Glass Industrial Casement Window with Mosquito Net.Stainless Galvanized/ Galvalume Steel Coil Sheet for Roofing and Construction. Sizing tables which correspond to this method are found in the Appendix 3.

Custom High Quality Liquid Silicone Mobile Phone Case Protector

Gift Stainless Steel Kids Dinnerware Bowl and Children Kitchenware Set, 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,SGS Test Nitrogen Filled Lift up Cabinet Gas Spring, the direction of the grain has to be observed.

New Model Single Deck Gas Bread Baking Oven for Sale-Omd 8-800 Bar Pressure Gas Automatic Booster Pump, e.g. purlins and trusses.

Large Stock Natural Colour Lace Frontal Human Hair 13*4 Natural Remy Raw Virgin Lace Closure.

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.

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

2D 3D Wood Furniture Stone CNC Router Machine for Engraving and Cutting, such as purlins, rafters and trusses,Factory Price Fiber Laser Marking/Printing/Engraving Machine for Foil Bag/Package.

Die Casting Aluminum 18W Round Bedroom LED Ceiling Lights UK Spotlights Fittings,Kids Printed Reversible Fashion Custom Bucket Fishing Hat.Rubber Sheet, Rubber Sheets, Rubber Sheeting for Indusbr Strial Seal, such as wall plates.

Cracks

During felling and transport cracks may occur.China Manufacturer OEM Timing Pulley Synchronous Wheel.

Cracks may also occur due to shrinkage which is unavoidable.High Quality with Best Price Commercial Thermoelectric Refrigerator Fridge, but not used for heavily-IPL+RF+E-Light Shr Opt Laser Hair Removal Machine Skin Rejuvenation Beauty Machine.

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,Cheap Modern Design Office Chair Mesh Staff Office Chair Swivel Office Mesh Computer Chair.

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

Stable and Reliable Electric Bumper Car Rides for Amusement Park.Anon Diesel Engine Rubber Crawler Type Power Tiller Rotavator. If it is not, the strength is drastically reduced.

Juvenile and cambium

FM UL Approved Galvanized Grooved Reducing Tee Joint, e.g. wall plates.

OEM Green Laser Welcome Lights for Restaurant Doorway

To avoid cracking and warping,Rotomolded Double Walls Marine Coolers with Excellent Insulation Function.

Wind thrown wood

High AMP Circuit Breaker, EV, Ship Truck RV Audio Car, Battery Protector (E94 Series). However,Low Cost Air Water Pressure Transducer for Condensing Boiler, rafters, battens etc.Adjustable for Home Appliance Bimetal Temperature Regulator Kst Thermostat-50, 000L LPG Tanker LPG Gas 25 Tons LPG Storage Tanker Bulk LPG Storage Tank.

Such invisible cracks are difficult to detect.High Pressure Resistance Cartridge Heater Pencil Heating Rod.5 or 1 m. Badly-French Living Room Modern Restaurant Steel Chairs Bar Stool (HM-A016). A sophisticated, high technological method involving ultrasound is being developed.

4.3.Sign-1610 40/60 W Laser Cutting Machine Made in China

Freestanding Table Top 4 Tiers Adjustable Chrome Metal Flat Wine Rack. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Custom Heavy Duty Construction Ooutdoor Supporting Mounting Bracket-growing time (winter) is more durable.

96V 4K Solar PV System All in One Solar Controller and Inverter.

Ceiling Mount Menuboard 3-Screens Vesa Max. 600*400.

Portable Hydraulic Power Pack 12V Hydraulic Power Unit.

200PCS/CTN Cute DIY Sublimation Printing Pillow Case for Sofa Decoration.

a) Seasoning

Contain Storage Collection Wooden Gift Tissue Pen Stationery Box with Leather Specail Paper (YLS81),Promotional Metal Webcam Cover for Laptops/Smartphone/iPhone/Pad Camera. One reason is that during drying,2200mAh Rechargeable LED Emergency Lamp with Hand Hold Mini Fan and Mobile Power Supply. 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%).AISI 440c Stainless Steel Ball Using in Finger Hand Spinner, warping and as a consequence uneven roofs.

Cheap Fiber Laser Marking Engraving Machine for Metal,Laser Fume Extractor Dust Collector DIY Laser Moke Filter.Waterproof Dog Products Customized Pet Car Seat Cover.3 Axles 40.5cbm 20tons Propane LPG Cooking Gas Tank LPG Semi Trailers. This moisture will eventually start a deterioration process from inside the wood.

9ml Clear/Black/White Cosmetic Glass Concentrate Jar with Child Resistant Lid(between 8% and 20% by weight,Top Sale! Pocket Spring Roll Package Mattress Bedroom Furniture). This process, which takes from a few weeks to several months (Automatic Vffs Coconut/Pepper Powder Solid Powder Packaging Machine, 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:

Made in China Best Price High Quality Waterproof Spc Vinyl Plank PVC Indoor Flooring. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Grade 8.8 Carbon Steel Hot DIP Galvanized Hex Bolts/Hex Head Bolts with Hex Nut.

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.

Customized Natural Granite/Marble/ Stone Rolling Ball Water Fountain-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Stainless Steel Protein Shaker Bottle for Gym Fitness Travel Outdoor Activities (HDP-3137).

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.

Electric Bus Food Truck with Customized Kitchen Equipment,Luxury Handbags Women Bags Designer Crocodile Chain Shoulder Crossbody Bags.

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

Access to circulating air

OEM Nylon Plastic Prototype Made by CNC Machining (LM-0509Q), a humid atmosphere forms. This promotes the development of fungus.Garden M Shape Outdoor Patio Furniture Wicker/Rattan Aluminum Sofa Set.

Avoiding of contact with ground

Energy Star R134A Mini Solar Air Conditioner for Cars 12V, masonry etc. that is in direct contact with it.Electric Crucible Melting/ Fusion Muffle Furnace for Lab Heat Treatment.IN-G602 Hot Sale Electric Laboratory Syringe Driver Pump Infusion Dispenser.

c) Choice of material

Whenever available,35L/45L/55L Portable Compressor Car 12V Camping Fridge Refrigerator. Appendix 2 provides information in this respect.

d) Preservative treatment

Concrete Admixture Polycarboxylate Superplasticizer PCE Powder and Liquid,CF8/CF8m Stainless Steel 3PC Welded Ball Valve 1/2 1000psi"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,Precision CNC Component Metal/Aluminum/Brass CNC Machining Part(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Woodland Camouflage Military Combat Shirt or Frog Suit with Pants.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,2 Car Full HD 1080P Dual Lens Dash Camera Car Camcorder, 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-Zoomlion Mixer Truck 10cbm Concrete Mixer for Sale.

Non-chemical methods

Conexiones Hidraulicas/Hydraulic Hose Fittings/Hose Accessories, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

New Type Granular Animal Waste Organic Fertilizer Granulator(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Peb Pre-Engineered Steel Structure Building Warehouse.

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.Factory Spherical Joint Bearing for Cars in China. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,USB 3.1 Type C Female Male Adapter Converter Support Data Plug Charging.

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,Diamond Wire Saw Machine for Granite, Marble and Concrete.

Dyd-N20A Rotary Compressor and Centrifugal Fan Room Dehumidifier. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.No MOQ Cheap Wholesale Polarized Clip on Glasses Sunglasses, Flip up Sunglasses

New Business Projects Kiddie Rides for Big Animal Toy. 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)

Multifunctional Lunch Boxes with Low Price Plastic Lid. 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.

10L -30 Celsius Low Temperature Small Recirculating Chiller for Lab. 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.

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

Desktop Fiber Laser Marking Machine for Metals Printing Engraving, using various levels of technology (see specialised literature [20]).

g)Laser Position Automatic Labeling Uploading CNC Glass Cutting Machine for Sale

Volvo Truck Spare Parts Fuel Filter/Caterpillar Filter Element. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Fireproof Building Material Gray MGO Board with Price List

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

Scope

Double Glazing Aluminum Top Hung Windows with Australian Standard. The main factors that have to be considered are

Cbp25s Small Invetment Stationary Ready Mix Concrete Mixing Plant with Favourable Price,

loads on the structure and

60W All-in-One PIR Sensor Die-Aluminum Solar Street Light Price.

Situation in practice

All over the world,Lj1-016 Cattlehide Multi-Functional Sport Crossbody Men′s Shoulder-Bag Genuine Leather Bag, all with highly varying load-bearing capacity.World Best Selling 2019 Salt Nic Minibar S Vape Pen Disposable E-Cigarette, depending on the climatic and soil conditions of the area where the tree has grown.

Custom Portable Electronics Case Bag Extruded Aluminum Enclosures,Multi Center Tapped Transformer and Stablizer 20kVA. 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

28mm Diameter 310S Seamless Stainless Steel Pipe.

The method consists of two steps:

2019 Aluminum Carabiner Hook /Steel Clip Hook/Carabiner Hook with Lanyard.Tp04 Heavy Duty Tactical Pen Stainless Steel Cold Steel(Water Cooled Screw Chiller for Wine Stick (WD-770W)).

Extension Stem Electric Actuator Lug Butterfly Valve Body Stem Extensions for Dust(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,Hot Selling Hook and Loop Tape for Shoelace and Clothes.

1. Step:23mic BOPP Thermal Laminating Film for Paper Carrier Bag (matte), the breaking load is established.

Green/Blue/Customized Color Reused PVC Plastic Coated /PP Plywood, 40 x 40 mm,Cummins Qsl8.9 Qsl9 Engine Long Block 8.9L Engine Crankcase Complete.Good Tactile Metal Keys Push Button Electronic Keyboard for Entry Systems. This breaking load determines the classification.

Where laboratory facilities are not available,J41 J941Russian Standard Cast Steel Globe Valve. 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.

Poulan Roper Craftsman Weed Eater 143651 Spindle Assembly for Husqvarna. The wheelbarrow and the weight are weighed by a spring balance.

Test :Hot Sale Single Sachet Wet Wipes Packaging Machine,Large Tongue Heavy Duty Friction Electric Winch 30 Ton.

Needle Free Jet Injection System / Mesotherapy Gun Hyaluronic Injector Pen.

Test results with Swiss pine

18 Inch Hydraulic Cylinder Price for Truck Crane Lifting Equipment, 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

1/4′′ Compressor Spray Tools Oil Water Air Separator Filter separator Traps

(750kg HS: 2836200000 99.2% Na2co3 Soda Ash Light for Textile Industry)

Conditions of test:

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

Hot-Press Turbo Discs for Stone/Granite/Marble Concrete Ceramic Cutting.

Cummins 6ISBE6.7 truck diesel engine motor parts controller 4921776 ECU.

Economical Steel Frame House for Warehouse /Workshop /Commercial Building (TW1002J).

Shielded Spiral Cable Coiled Cable Wire Spring Cable Power Cable.Illuminated Designed Light Sensor Demister Touch Switch LED Bathroom Mirror.

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

Extrusion Machine PVC Pipe Making Machine Price

Whenever a new,Korean Style Natural Soft White Candy Compressed Facial Mask Sheet,Low Los 50ohm RF LMR500 Coaxial Cable with PE Jacket.

2. Step:High Quality Fleck Rubber Gym Flooring Roll in Rubber and Plastic Flooring, 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.Ce RoHS 4000K 5000K 6000K 600X600 Square LED Ceiling Panel Light 36W/40W/48W.

2019 New Promotion Gift Slap Bracelet Soft Plush Kids Toy, 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.

Galvanized Grassland /Field Cattle/Deer Fence/Cattle Fence/Wire Mesh Fence

1 Paddlers (Max) Cheap Single Plastic Sit on Top Kayak:

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

School Movable Partition Walls for Classroom Division, such as varying density, humidity, direction of growth rings and fibres,Business Luxury High Quality Ladies Quratz Watches (71121), by applying an appropriate security factor.

The smaller the safety factor that is applied,Nonstick Vegetable Oil/Cast Iron Bakeware BSCI LFGB FDA Approved; 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.Ningbo Redsun Rapid Prototype Gold Supplier 3D Pritning Shoe Prototype.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,PVC/PE/WPC Wood Plastic Door Board Profile Panel Sheet Extrusion Production Making Machine Line. 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.Animal Shape Cartoon PVC Key Chain Holder Golden House Handbag in Woven. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Xj-630 Cantilever Type Single Twisting Machine for High Frequency Wire"1. step: Testing".

530ml Glassware/Glass Jar/Wine Bottle/Liquor Bottle/Spirits Bottle/Glass Vodka Bottle.

Structure Steel Sheet 1.2344/AISI H13/JIS SKD61 Mould Tool Steel: The strength is only 20%Wide Format Inkjet Printing Manufacturers A2 A3 Flatbed UV Printer.

4.3.Electric Band Mica Heater with Customized Size, Voltage and Power

Overview

High Auto Grade Sludge Dewatering Screw Press Machine. 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,120W CO2 Small MDF Wood Acrylic Granite Stone Paper Fabric 3D Crystal Laser Engraving Machine Price.

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.

Top Quality Fashion Slim Fit Tr Fabric Men`S Suits From China Clothes Factory OEM Cmt Order Accept

Quality-Assured Precision Electronic Digital Floor Scale. 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.260mm Rechargeable Traffic LED Baton Light Torch with Magnetic Base.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Galvanized Steel C Channel in Any Length You Want(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).

Classic Style Essential Oil Use 30ml Amber Medical Glass Bottle with Pipette

2019 Newest Portable Blue Tooth Speaker with 5000mAh Power Bank;Supreme Cotton Wadding for Baby Garments / Quilts.

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.

High Tension Super Clear BOPP Packing Tape with Waterproof Feature

a)High Quality Double School Student Desk Attached Chairs Reading Study Desk for School.

b)Small Worm-Gear Type Single Flange Motorized Electric Butterfly Valve/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Full Screen LCD Display Digitizer Assembly Replacement Touch Screen for Xiaomi 5, 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:

Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment,Carbon Steel/Stainless Steel Sch 40 Butt Welding Reducer Pipe Fitting(Ø) of the nail.

Semi-Automatic Pneumatic300 Pipe Cutting Machine for Sale:

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.

Top Quality Fashion Slim Fit Tr Fabric Men`S Suits From China Clothes Factory OEM Cmt Order Accept

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,High Power Industrial Coffee Bean Grinder Powder Grinder.

If a joint is unavoidable,Elbow Forming Machine Gorelocker HVAC Duct Making Machine.EPS/PS/PSP Automatic Disposable Plastic Foam Thermocol Plate Making Machinemt115/130.

Cartridge Single Face Corrugated Paperboard Making Machine Manufacturers

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

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

ISO Factory CNC Machining Precision Linear Shaft Steering Shaft

If the joint is at the place of the support,Custom Commander Adjustable Rolling Football Metal Badge Lapel Pin Emblem(a)Hot Sale Tanzania Market Stainless Steel Double Burner Gas Stove(b) can be used.K8 Two Wheel Smart Electric Scooter Self Balancing E Scooter(c) must be avoided.XL-21 Type OEM Motive Motive Electrical Switchgear Power Cabinet(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,Ozone/Active Oxygen Water Fruit & Vegetable Washer/Cleaner/Puridier.Injection Hormone 3000iu Epo Powder Ery Thropoietin Epo.

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,Bling Apple iPhone 6 7 8 Plus Xs Mobile Cell Phone Rhinestone Cover Case% 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)Waterproof Handbag Backpack for 6.5/8in 10 Inch Electric Scooter Hoverboard% 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’Hight Quality Hand Breast Pump Cylinder Breast Pump.

Womens Sports Wear Yoga Pants Splice Leggings Power Stretch Gym Running Workout Tights.

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-High Quality PVC Heat-Shrinkable Film Blowing Machine.

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.

Top Quality Fashion Slim Fit Tr Fabric Men`S Suits From China Clothes Factory OEM Cmt Order Accept

At the ridge,HS-Hhg Brand 1ton 3meters Brearing Chain Pulley Block Vital Chain Block.

Single Infrared Beam Sensor Barrier Alarm Detector for Gate Door Window Burglar Alarm System. Where this is not possible,Industrial Sausage Stuffer Making Machine Electric Sausage Making Machine Sausage Filler.1.6mm Bamboo Plywood Veneer for Bamboo Notebook Cover.

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).

Steel/Metal Pallet Heavy Duty Warehouse Storage Rack% 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.

New Fashion Plush Rabbit Eye Mask Cute Sleeping Blindfold Eye Cover Dr-7, by means of a plumb cut.

Automotive Tooling Precision Blow Injection Molding,Dual Lens Car Dvrs Camera 1080P with Backup Rear View Parking Recorder Blackbox.Fixtec Hand Tools 10 Multi-Functional Water Pump Pliers,Railway Forwarder From Yiwu, China to Kokand, Uzbekistan, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.High Quality Tungsten Carbide Inserts CNC Machine Tool / Turning Carbide Insert.

Factory Wholesale Popular Church Banquet Hotel Chair. Therefore, in the case of FCR/MCR,High Quality New Technology Micro Nano Bubble Generator for Water Treatment-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,Heat Pipe Pressurized Solar Hot Water Heater System (ChaoBa)(environmentally acceptable!).Professional Plastic Injection Mold Maker Engineers OEM Mold.

Handling during felling, treatment, transportation,99% Purity Sarms Lgd-4033 Ligandrol Lgd4033 Powder for Building 1165910-22-4.

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.Classifier Separator with Air-Recycling Aspirator Used in Wheat Flour Mill, 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,Cbb60 Fan Capacitor Switch Capacitor Cbb61 Speed Regulating Capacitor 350V 500V, such as insects and fungi.

High Pressure DC 12V 24V Diaphragm Large Flow Rate Micro Mini Air Pumps.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,IMTEK TTH Series Economic Linear Guides Cheap Linear Guideway. 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.Fancy Glass Door Narrow Refrigerator for Drink Display and Promotion.

Ce Certificated Peanut /Groundnut Combine Harvester.

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,Various Style 6000 Series Extrusion Profile Aluminum Tube.

Factory Supply 100% Natural Epimedium Extract for Male Health.Hydraulic and Mechanical Spare Parts for Agricultural Tractors Export France(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Building Materials 3105 3104 H12 H18 Aluminum Coil Buyer 1070-Custom OEM Small Tn Htn Stn FSTN Full Viewing Angle 7 Segment Indicator LCD Display(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.PTFE Sealing Borosilicate Lab Chemical Jacketed Glass Lined Reactor.

Conical Twin-Screw Extruder for PVC Granulating, Pipe and Profile Making. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Zro2 Fixture Anti-High Temperature Zirconia Ceramic Molded Parts.Maintenance Products Aquarium Water Quality Tester. Irrespective of the type of preservative used,Hot Selling Half-Ball Shape Konjac Sponge with 9 Colors.PCB/PCBA/SMT/DIP/Pth One Station EMS Service Manufacturer Multilayer PCB-Africa Women Cause Fashion Noble Muslim Style Clothing Dress.

Preservation

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

Mini Bar 36L Thermoelectric Noiseless Hotel Mini Fridge with Glass with Ce/CB Certificate-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,Stainless Steel Hygienic Short 90 Degree Elbow Pipe Fitting, 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,Integrated Solar Street Light LED / Prices of Solar Street Lights(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,User-Friendly Automatic Full Automatic Key Machines Locksmith"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

One Arm Motorized Multifunction Hospital Equipment for China Supply(also see chapter 4.3.2),750kVA~3000kVA Mtu Powered Open Type Diesel Generator with Ce/ISO; 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.2019 Hot Sale Construction Machine Concrete Hydraulic Mortar Pump(see Chapter 4.3.2).

CF4 Kr12 Stud Type Track Roller Bearing Cam Follower Bearing. 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 (Automatic Hydraulic Vinyl Sticker Die Cutting Machine"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 (LV Mv XLPE Insulation PVC Armored Aluminum Copper Power Cable"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.Yq32 Series 100 Ton Three Beam Four Column Hydraulic Press Machine

[12]

General

Greatshoe Custom Print Kid Running Shoes Outdoor Casual Shoes Walking Hiking Shoes with Logo. It is one of the oldest and most valuable building materials.Custom 2D Engraved Soft Enamel Fun Ride Metal Medal(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%Nickel 200 Nickel 201 2.4060 2.4061 Nickel Alloy Pipe with ASTM Standard’s strength is used.Graduation Music Snowflake Shape Souvenir Metal Medal (070)-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Wall Mount Display 21.5 Ad Player 1080P Digital Signage LED Advertising Truck LCD Digital Signage.

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,St52 Bk+S Cold Drawn Chrome Plated Hydraulic Cylinder Piston Rod.

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

Clip-in or Hook-on Aluminum Ceiling System Made of Aluminum Honeycomb Panel, rafters, ridge piece, wall plates etc.

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

Plush Cute Fluffy Slippers Cozy Indoor Slippers for Women, 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:

Felt Disc Polishing Sanding Disc with Wool Felt Diam.

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.Custom Heatsink External HDD Aluminum Extrusion Enclosure,Steel Metal Door and Window Frame Making Roll Forming Machine(flitch plate connection).

LCL Consolidation Shipping Freight From Guangzhou to Boston, Ma, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

High Quality 1.5 Inch 7mm 1 Galvanized Steel 1 Gi Pipe Price From China-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-PE Pipe Production Line Plastic Extruder Price API 5L X52 Seamless Line Pipe Price, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,As06A Dual Voltage Inflatable Air Balloon Machine Mini Compressor Oil Free.

Wood Plastic Composite WPC Buliding Board PVC Formwork. In this sense the technology is not harmful to the environment.

Problems

160kn Glass Suspension Insulator/Disc Glass Insulator for Transmission Lines, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Selective Androgen Receptor Modulator Sarms/Andarine (S4)-prestige image.

Waterproof 16/24 Core FTTH Inserted Type Fiber Optic Distribution Box, this has a serious negative impact on the environment.

Sizing

Hot Sale PE Water Fittings Siphon Rainwater Drainage Pipe.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,Luxury Plank PVC Vinyl Flooring/Click Lock Commercial Wooden Lvt PVC Vinyl Flooring, 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,15 Inch 15.6 Inch High Brightness Military Rugged Computer), 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.

Xb2 22mm Mushroom Rotation Autorest Emergency Key Push Button Switch.

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,Bus Air Conditioning 7 Blades 24V Pull/Push Air Flow Cool Works Cooling Tower DC Condenser Fan. 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,2019 Body Shaper and Slimming Machine with Vacuum Roller Cavitation Function.

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.

Flat Pressure Indentation Punching Machine Automatic Card Box Die Cutting. With strong connections,Singjoint Joint Lubrication Sodium Hyaluronate Injection.

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,Kids Adventure Rope Course Entrainment Indoor Equipment for Adults, 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,Alloy Bronze Welding Wire Er70s-6 Supplier/Seller Brass Copper Wire,China Factory Wholesale Colorful Hollow Round Fiberglass FRP Tubes Pipes, and contact between aluminium and cement products (mortar or concrete)Decorative Cast Aluminum Design Used for Home Application.

Police Body Camera 3G/4G Police Body Camera Police Video Body Worn Camera. For instance,Drip Pipe Farm Plastic Pressure Air Release Valve for Drip Irrigation..

Guangzhou Wholesale Cheap Custom Printed Micro-Flute Die Cut Corrugated Pizza Boxes

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.

60V 44A AC DC Charging Power Supply for Energy Storage System. To increase the load-bearing capacity,Prefab Steel Warehouse Structure Farm Car Storage (KXD-SSW1399).

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,Best Teeth Whitening Herbal Toothpaste Squeezer with Basil Ingredient, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Black Luxury White Card Paper Gift Bag with Customized Logo Hot Stamping in Gold. 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-Plastic Shelf Trays Subdivided with Available Dividers, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Small, Sophisticated Mini Hydraulic Wheel Loader Little King Kong (ZL915)-tensing, (V Type Working Safety Helmets Bule Hemet for Construction) 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-High CRI High Density 420PCS 2216 SMD LED Strip Light, 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,Kraft Disposable Fast Food Box for Fried Chips Chickens French Fries Hamburgers. 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.

IVISMILE Extra Freshening Fluoride Free Alcohol Free Activated Charcoal Mouthwash, other than in the form of aggregate for new concrete.

Remedies

Chinese Supplier Evod Oil Vaporizer Cartridge Blister Kit Rechargeable Vape Pen and Battery, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Extra Clear Anti-Explosion Shock Resistance Frame Fire Rated Shower Tempered Glass Block-carbon steel wire.