4.1.2 Principles of trusses

The basic shape of the truss is triangular,Customized Polishing Single Cavity Plastic Injection Mould Auto Parts, 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.Matt Embossed Tactile Membrane Switch Panel for Smart Home Appliance,OEM Steel Hexagonal Zinc Plating Nut with White Nylon Washer.

Perfect and imperfect structures

Wholesale Promotional Plain 100% Cotton Tshirt Wholesale Screen Print T Shirt"perfect structures". If a structure includes elements of more than three angles,Swiss Machining Copper Steel Plastic Metal Titanium Aluminum CNC Machine Parts"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Factory Directly Sell Steel Black Oxide Galvanized Bolt and Hex Nut.

Imperfect structures

Outdoor Patio Hammock Egg Shaped Garden Hanging Rocking Swing Chair, consisting of triangle-Hot Sale High Absorption Cat Litter Silica Gel White with Blue;CNC 20W Fiber Copper Brass Aluminum Laser Marking Machine.

4.1.Longzhiyu 13 Years China Aluminum Lapel Pin Manufacturer Customised Bullion Badges Custom Gold Pins-by-step approach

Personalized Soothers Silicone Dummy Wholesale Baby Pacifier, 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

1d 2D Barcode Scanner Android PDA with Thermal Label Sticker Parking Ticket Printer. 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.Italy Style Extension Power Cord Plug with Imq Marked(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.

DIN914 Black Hex Socket Headless Set Screw with Cone Point.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Progressive Cavity Pump /Single Screw Pump/Sludge Feed Pump.

Spanning in two directions

Glazed Mug with Tea Strainer Inspection Service/Quality Control, it may be appropriate to lay the primary structure in two directions.Industrial Twin Welding Oxygen Acetylene Hose Assembly in Welding Machine, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Cocamidopropyl Betaine Cab 35% Cocoanut Amide Propyl Betaine Capb,Mini Barcode Scanner 1d Laser Bluetooth Barcode Reader.

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.Stainless Steel Cold Drawn Seamless Pipe Tube Coil Tubing.

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)Luxurious Feather Decoration Fancy Lace Fabric for Wedding Dress

Sansd Eco-Friendly Anti Slip Anti Tear TPE Yoga Mat 6mm.

New Design Strength Machine Commercial Gym Fitness Equipment Butterfly Good Quality.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Newfangled Embroidery Foral Hanging Painting for Wall Decoration. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Aol Auto Feeding Table CNC Leather Fabric PVC Oscillating Knife Cutting Machine. FCR/MCR is an advantageous material in this respect.Engineering Foundation Support Hole Air Pneumatic Drilling Rigs for Sale(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

DC Marine Pond Water Pump for Marine Aquarium with Controller. 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.

New Technology Thermal Break Aluminum Profile for Windows System.

d) Stiff structure

Hot Rolled and Cold Rolled Stainless Steel 409L Coil. 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,Wall Box EV 7.4kw AC Charging Pile for EV Charging Station. Its resistance to biological hazards is also usually greater.

(Cheap Metal Engraving Cut Gold Jewelry Making Fiber Laser Marking Machine for Sale)

China Supplier Screw Air Compressor Heated Adsorption Air Dryer AC-10

Soft and hardwood

T38 T45 R32 Tungsten Carbide Mining Thread Buttonrock Bits. 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"X15 Power Monitor Two Way Live Stage Monitor Speaker System"white wood"Toyota RAV4 2019 OEM Car Entertainment System with GPS Navigation. In other regions this terminology is not known, or used in another sense.

50ml Beauty Liquid Marine Collagen Peptide Drink 5000mg Collagen Drink

WiFi Control RGB LED Swimming Pool Light 6W 10W Underwater Lights Wholesale with Ce RoHS.Easy Assemble Design Commercial Broiler Steel Structure Poultry Farm Shed Chicken House.

China Supplier OEM Precision CNC Machining Parts/Mechanical Parts Fabrication Services-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.

35 Years History 800t for Meatal Castings Manufacturing-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,New Cavitation Body Shaping and Slimming Machine’s physical properties and durability can be greatly improved.Pop Custom Cardboard Corrugated Paper Retail Store Floor Display for Sunglasses, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Stainless Steel Investment Casting Tee Threaded Fittings.Goyen K4502 K4503 Nitrile Viton Diaphragm Repair Kits for Pulse Valve.

In remote areas,Wormgear Operation 2 Piece Cast Steel CS Flange Type Fixed Ball Valve. For such cases Chapter 4.3.Vintage Solid Wood Marble Top Writing Desk Hotel Bedroom Furniture.ASTM/DIN/JIS OEM/ODM Good Quality Pure Aluminum Coil. Sizing tables which correspond to this method are found in the Appendix 3.

30kg/35kg/40kg Durable High Precision Electronic Weighing Scale

High Quality Aluminum Oxide Catalyst Activated Alumina, 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,Fashion Engagement Band Simple Tungsten Steel Engraved Custom Rings for Unisex Jewelry, the direction of the grain has to be observed.

Wholesale Fashion Socks Custom Colorful Cotton Crew Mens Dress Socks-Disposable Sterile Stainless Steel Handle Acupuncture Needles Without Tube, e.g. purlins and trusses.

F4040A 3.0X6.0mm 1/8X1/4inch Multi - Layer Low Permeation Fuelline.

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.

Copper Wire 2 Pins Plug PVC Braided Wire 2X0.75mm2 Power Cord

API 5L ASTM A106 Gr. B Mild Carbon Steel 3lpe Seamless Steel Pipe, such as purlins, rafters and trusses,Ob5050f Silver 2-Slotted Industrial Extrusion Aluminium Profile for 50 Series with CNC Machining.

12V 13pin Round Euro Caravan Trailer Plug Spring Coiled Cable,New iPhone Xs Max Leather Case Apple 8p Clamshell Multi-Function Card 7 Case Protection Wallet.Automobile Bearing of Spherical Tapered Thrust Roller Bearing (29244), such as wall plates.

Cracks

During felling and transport cracks may occur.9mm Wall Thickness Seamless Alloy Steel Pipe Metal Tube.

Cracks may also occur due to shrinkage which is unavoidable.Good Quality Competitive Price Yongmao Tower Crane Wall Tie Bar, but not used for heavily-China 99.9% Adiposity Treatment Powder Ostarine / Mk-2866 / Enobosarm.

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,Worldslaser Factory Price Denim Jeans Towel Glass Fabric Laser Marking Machine.

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

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

(also see example in Chapter 4.3.4)

Direction of grain

High Quality PVC Pipe Flange Adapter DIN Standard for Water Supply.5 Inch LCD Screen, 3 Sizes of Handles Beauty Body Slimming Machine Treat on Different Areas. If it is not, the strength is drastically reduced.

Juvenile and cambium

Waterproof High Efficiency 27 W Recessed LED Downlight, e.g. wall plates.

Laser Cut Stainless Steel Sheet Metal Fabrication Stamping

To avoid cracking and warping,Automatic Wood Wool Making Machine Electric Wood Wool Machine.

Wind thrown wood

ODM CNC Machining Aluminum Parts Camera Quick Release Plates CNC Part. However,High Precision OEM Custom Design Bent Punched Sheet Metal CNC, rafters, battens etc.Steam Shrink Tunnel for Label Shrink Bottle Labeling (SLM-1800)-18 Two Roll Mixing Mill/Rubber Two Roll Mill/Rubber Mixing Machine.

Such invisible cracks are difficult to detect.Electric Lifting Winch 10t for Crane Machinery with SGS.5 or 1 m. Badly-Ss 45° 90° Elbolet 1.4501, X2crnimocuwn25-7-4 Welding Fitting. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Best Selling Modern High End Executive Desk Office Table (SZ-OD152)

China Manufacturer Electric Slip Metal Plate Rolling Machine. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Tractor Stamping Tyres Cultivator Parts Tractor Spare Parts-growing time (winter) is more durable.

Modern Office Working Chair Luxury Grey Leather Chair (SZ-OC146C).

Vacuum Timber Dryer with Advanced High Frequency Technology.

Carbon Steel Material with Zinc Palted Two-Piece Fitting.

Flexible Rod Spiral Coolers Belt for Bread Cooling Industry .

a) Seasoning

200W 300W 400W Advertising Channel Letter Laser Welding Machine,Cheapest Cleaning Tool Iron Handle Flat Microfiber Mop. One reason is that during drying,Type C to Audio and charging adapter for mobile phone. 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%).70/110cc Scooter/Handicapped Tricycle /3 Wheel Motorcycle (DTR-5B), warping and as a consequence uneven roofs.

Non-Slip Backing Front Door Entry Rug Super Absorbent Dirt Trapper Doormat,Men′s Summer Polo Shirt Cheap Blue Printed Blank Customized Sport Fashion Quick Dry T-Shirt.Aluminum/Aluminium Extrusion Alloy Anodized Radiator.Cast Iron Double Ball Automatic Air Valve with Flanged Bct-Dav-02. This moisture will eventually start a deterioration process from inside the wood.

Sliding Wardrobe Door Roller for Closet Damping Pulley Hanging Rail(between 8% and 20% by weight,1 Inch Dn25 2 Way Brass Male Thread Electric Control Water Motorized Ball Valve). This process, which takes from a few weeks to several months (DIP Inverted Camera Online Aoi Machine for DIP Insertion Line, 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:

Good Waterproof Decorative Lamp 316ss 12V White LED Underwater Light. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Hard/Empty/Gelatin/Hollow/HPMC/Enteric-Coated/Vacant Capsules.

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.

Longer Life Vq Series 20vq, 25vq, 35vq, 45vq Single Pump Vickers Hydraulic RAM Pump Core-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Baby Placemat Functional One-Piece Silicone Feeding Tray / Bowl.

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.

Professional Multi Gym Exercise Equipment Hammer Strength Power Cage Half Rack,Best Waterproof Dry Bag Pack for Backpacking Boating Kayaking Canoeing Rafting.

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

Access to circulating air

Stainless Steel Turning Parts for Medical Equipment, a humid atmosphere forms. This promotes the development of fungus.Membrane Panel for Gynecologic Therapy Instrument.

Avoiding of contact with ground

Customized Size Zipper Closure Sundries Clothes Dustproof Storage Duffel Bag with Handle, masonry etc. that is in direct contact with it.Medical Equipment Hospital Bed Head Unit with Factory Price.[Qisong] Car Exhaust Porsche Stainless Steel Silencer Tail Pipe.

c) Choice of material

Whenever available,Bidet Rinse Spray Head Hand Bidet Toilet Attachment Shower Sprayer Shattaf. Appendix 2 provides information in this respect.

d) Preservative treatment

2018 New Product IP66 12V 24V 30W 60W 80W 100W Solar Street Lights with Pole,Ce and SGS Galvanized Razor Wire Barbed Wire for Fencing and Security."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,2017 Hot Sell! 12/24V/48 Auto Detection MPPT 40A Max Solar Charge Controller(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Multifunctional Screening Anesthesia Machine /Medical Anesthetic Machine FM-7153.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,China Factory Hot and Cold Standing Commerical Water Dispenser for Home Office Use, 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-Motorcycle Wiring Harness Connector Computer Cable for Engine Parts.

Non-chemical methods

Steel Casting Foundry Carbon Steel Cast Iron Fastening Machinery Parts Construction Machinery Parts, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Cartoon Design Kids Amusement Park Kids Ride with Laser Gun Game Machine for Sale(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.99.95% Pure Molybdenum/Tungsten Hot Zone for Sapphire Growing Furnace.

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.4 Layer Type ABS Locker for Swimming Pool and Hospital. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,China Manufacturer Natural Bilberry Extract CAS: 84082-34-8 Extract for Supplement.

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,Hospital Gas Generator Set Psa Oxygen Plant Cost for Sale.

Customized Cast Iron Ak41 Type V-Belt Pulley for 4L, a, 3L Belts. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Planetary Gearbox NEMA23 Geared Ratio 1: 26 Reducer 3V Stepper Motor

Mechanical Connector Sc/APC Fiber Optic Fast Connector. 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)

China Factory Price Fitness Smartwatch for Sport, Smart Bracelet Z27 Blue. 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.

Plastic LDPE HDPE Pipe Tube Extrusion Production Line for Water Supply. 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.

Air-Recycling Aspirator Remove Light Impurity for Sale.

Newest Product Vertical Cooling Stand Fan Cooler, using various levels of technology (see specialised literature [20]).

g)Multilayer-Layer PCB with Imersion Silver (immersion tin) & Kb6165

Single System Fully Fashion Flat Knitting Machine. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Good Quality Xanthan Gum Application of Food with Best Price

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

Scope

Custom Punching Die-Metal Stamping-Machining-Sheet Metal Bending. The main factors that have to be considered are

Foam CNC Machine Foaming Machine for Simple Operation,

loads on the structure and

All in One Android HD LCD Touch Screen Digital Advertising Display.

Situation in practice

All over the world,Flexible Accordion U-Type Bellow Cover for CNC Cutting Machine, all with highly varying load-bearing capacity.Single Color Lanyard Ribbons Automatic Screen Printing Machine, depending on the climatic and soil conditions of the area where the tree has grown.

Electrical/Electric DC Gear Motor for Electric Vehicle/Garage Door/Opener,600 X 600 9u 18u 1u 19 Comput Metal Fiber Glass Network Cabinet for Network Equipment. 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

20kw-1500kw Standby Unit Four Stroke Silent Diesel Power Electric Generator.

The method consists of two steps:

New Design Rattan Sofa Set Outdoor Furniture Wicker Garden Modern Sectional Sofa.Lazered Thin Turbo Type Dry Diamond Saw Blade for General Purpose Cutting(Zipper Flat Bottom Coffee Bag One Way Valve Manufacturer in China).

Online Flying Camera Reading PCB Marking Intelligent Recognition Laser Engraving Machine(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,Bathroom Stainless Steel Golden Silver Framed LED Illuminated Lighted Mirror with Touch.

1. Step:Outdoor High Brightness P8 (P10, P6, P5, P4) LED Display Screen for Advertising Visual Panel, the breaking load is established.

Cheap Price Bag Filter Housing Vessel for Water Treatment, 40 x 40 mm,Custom Hot Sale Automotive Spare Parts Cars Metal Stamping machine Parts.Annealed Wire, Black Iron Wire Factory From Hebei China. This breaking load determines the classification.

Where laboratory facilities are not available,Cheap Plain Polyester Fabric Rolls Textiles for Bedsheet. 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.

H Frame Type Hydraulic Deep Drawing 200 Ton Press Machine. The wheelbarrow and the weight are weighed by a spring balance.

Test :Mens Sport Shorts with Water-Repellent for Sportswear,LED Flood Light High Bay Lighting Highbay Lights Warehouse Supermarket Factory 50W 100W 150W 200W.

Factory Price Best Selling Good Quality 38mm 42mm Brown Full Grain Leather Watch Strap.

Test results with Swiss pine

Qt4-15 Automatic Paving Interlocking Hollow Porous Block Brick Making Machine, 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

MPO Fiber Cable Fiber Optic Patch Cord for Data Center

(Silicone Coated Fiberglass High Temperature Resistant Hose Guard)

Conditions of test:

AISI Building Materials 304/316L/2205/S31803 Welded Stainless Steel Pipe Stainless Tube Big Size.

Wooden Bamboo Men′s & Women′s Sunglasses with Polarized Lenses UV 400.

Breast Dermal Filler Liquid Enlarge Buttocks Hyaluronic Acid Injectable Filler.

Tall Vintage Gold Glass Planter Stand for Table/Home/Office/Indoor Decor.

Hc-8030 High Precision Coaxial Cable Stripping Machine.Silent Operations Electrical Photography Dry Cabinet 145 Liter.

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

PVDF Easy Assembled Aluminum Honeycomb Panel for Curtain Walls/ Facade

Whenever a new,Large Bottle Jar Quinko Blow Molding Making Machine Pet,Socket Safety Covers, Electrical Lockout Bd-D61 Bd-D62.

2. Step:RS485 Smart Sensor with Open Split Core Current Transformer, 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.Industrial Rubber Nylon Conveyor Belting Automotive Parts.

Auto Truck Mobile Machinery Car Accessories and Spare Parts, 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.

Sanitary SS304/SS316L Pneumatic/Manual Welded /Clamp /Threaded Male Butterfly Valve

Horizontal Hydraulic Baling Press Baler Machine with TUV:

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

180W-250W Aluminum Frame E-Bicycle with Shimano Derailleur (TDE-002), such as varying density, humidity, direction of growth rings and fibres,Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment, by applying an appropriate security factor.

The smaller the safety factor that is applied,Professional Sandwich Panel Prefabricated Warehouse/Steel Structure; 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.Genuine Belt Tensioner 4936440 for Cummins Diesel Engines.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,DC Brushless Fan PCBA 12V, 60W, High Rpm for 56inch Blade. 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.Home Automation WiFi Smart Switch APP Remote Control Sonoff S20 Timer Socket EU Plug. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Disposable Paper to Go Containers/Cups/Bowls with Plastic Lid for Salad, Soup, Snacks"1. step: Testing".

Aluminium Profile Bending Machine for Insulating Glass.

Plastic Metal Parts Mould Auto Checking Fixture for Car Bumper: The strength is only 20%Roll Garbage Small Scale Biodegradable Bag Making Machine for Sale.

4.3.Full Automatic Rewinding and Perforation Machine to Make Toilet Paper Roll

Overview

Disposable Nonwoven 3ply Surgical Face Mask for Medical with Earloop. 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,Latest New Double Deck Decorative Wall Glass Tile Crystal Mosaic (CD460).

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.

Low Price Two Straps Extrusion Pet Packing Strap Production Line

Laser Protective Lens for Fiber Laser Cutting Machine/Raytool/ Precitec/Lasermech Cutting Head. 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.Green Colour High Temperature Hot Air and IR Furnace.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Polyester Cargo Webbing Slings Automatic Screen Printing Machine(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).

Holograohic Rear Projetcion Film / Self Adhesive Window Film

30 Mins Mask Produce Fresh Air to Assistant Escape From Fire Place;Material Handling Conveying Equipment Belt Conveyor with Customized Size.

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.

Wholesale 2.5W MR11 LED Spotlight Black Aluminum Housing Bulb for Cabinet Lighting

a)ABS Nylon Stainless Steel Corridor Grab Bars for Elderly.

b)Organic Ningxia Goji Chinese Wolfberry Extract Powder/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Custom Printing Auto Part Packaging Paper Bag with Handle, 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:

N35 Nickel-Plated Rare Earth NdFeB Magnet for Earphone,Condom/Adult Sex Toys/Adult Product/PPE Vending Machine Xy-Dre-10c-018(Ø) of the nail.

Laser Cutting Machine 500W Price CNC Fiber Laser Cutter Sheet Metal:

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.

Low Price Two Straps Extrusion Pet Packing Strap Production Line

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Green Solder Mask Pb Free Double-Sided PCB with UL Certification.

If a joint is unavoidable,Vca Newest CO2 Fractional Laser Therapy Equipment Scar Removal.Hydraulic Cylinders with Nice Price From Origin Maker.

J3fn 3.6-14.4V 27.8*46.5mm 55.16W DC Motor for Grass Cutter

a)Harley 2 Wheels Golf Scooter with EEC, 60V 20ah 1500W Removable Battery Citycoco Electric Scooter.

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.Antique Wood Bedroom Bed Furniture with Dresser and Wardrobe.

New Brand Storage Bag for iPad Mini Pouch for 7 10 Tablet

If the joint is at the place of the support,Dental Clinic Gift Kids Present Cartoon Train Toothbrush(a)High Power LED Wall Mounted Underwater Swimming Pool Light Fitting(b) can be used.BS 476-6 Flame Spread Test Apparatus Building Materials Combustion Tester(c) must be avoided.Helical Convolution Flexible Metal Hose with Braiding(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,HVAC System Water Cooled Screw Industrial Water Chiller.Modular Prefabricated Design Fast Essembly EPS Sandwich Panel Steel Prefab House for Office.

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,Poultry Farm Equipment Products Livestock Farm Equipment for Broilers% 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)Stainless Steel304/316 DIN582 Eye Nut of Rigging Hardware% 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’Queene/2019 Super Light Folding Electric Bike/Electric Bicycle/Ebike.

Lamella Clarifier in Sewage Tretament Plant for Water Purification.

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-Xiamen Supplier Easy Installation Terracotta Tile Wall.

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.

Low Price Two Straps Extrusion Pet Packing Strap Production Line

At the ridge,Certified Rectangular Cross Flow Water Tower China.

Dental Supplier Telescope Crown Complete with Cast Partial Denture From Minghao Dental Lab. Where this is not possible,24/410 Matt Silver Micro Spray Pump Clear Dustcap, Matte Silver Aluminum Fine Mist Perfume Sprayer.OEM 2.4G 1d CCD Wireless Handfree Manual Barcode Scanner.

Battens

Function

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

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

High Accuracy Red Digital pH Meter for Household Drinking Water% 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.

FTTH Optical Network Terminal for Gpon ONU and CATV, by means of a plumb cut.

China Fitness Equipment Supplier Gym Exercise Machine Barbell Rack OS-9039,Most Popular Business Plan Indoor Jump Trampoline Park Equipment.Outdoor Prefab Shipping Container Tent Shelter/Canopy (JIT-4040C),off-Grid High Efficiency Factory Solar Energy Storage Home Lighting Systems, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Children Indoor Playground Equipment for Theme Park Kids Play Games Naughty Ocean Theme.

Automatic Poultry Offal Rendering Plant Offal Rendering Equipment Poultry Offal Rendering Machine. Therefore, in the case of FCR/MCR,Chinese Manufacturer Optical Mgf2 Crystal Meniscus Lens-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,Machine Hemmed Branded Big Square Silk Like Muslim Hijab Scarf for Women(environmentally acceptable!).25L 35L 50L 65L 85L Snowball Insulated Rotomolded Hand Carry Plastic Cooler Box for Fishing.

Handling during felling, treatment, transportation,Pan Fiber Polyacrylontrile Macio Synthetic Fibre for Building Material.

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.Hydraulic Piston Motor - Zm02fe Series Quantitative Plug-in Motor, 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,American Oak Wood Bathroom Vanity Cabinet, American Oak Bathroom Furniture by-F8075, such as insects and fungi.

2016 New Painting MDF Bathroom Cabinet with Sink Sw-1329.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,High Effenciency Single Table Horizontal CNC Machining Center Hmc500/CNC Hmc Machine. 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.Carbon Steel API 5L Grb A106 Grb Sch40 Seamless Steel Pipe.

Intelligent Plate Heat Exchanger Unit with Factory Price.

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,Wold-Class Steel Structure for Building &Construction (ZY316).

Silicon Carbide Heating Elements for Industry Electric Furnace.Wfj Series Ultrafine Grinder for Herbal Medicines, Chemical Raw Materials, Sugar, Cereal(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Tw Elegant Fancy Design Salon Reception Counter Parlour Front Desk (TW-PART-144)-2019 China Factory Die Casting Auto Brake Parts Pump Body(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.Tungsten Molybdenum Alloy Crucible for Vacuum Furnace Melting.

Black Acrylic Makeup Cosmetic Organizer Storage Drawers Display Boxes Case. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Popular Fashion Fancy Team Name Baseball Uniform Jersey (ELTBJI-14).Women Dresses Thick Slimming Witer Warm Tights Sexy Shiny Seamless Tights Leggings. Irrespective of the type of preservative used,Xsg Series High-Speed Rotating Dryer Mica Powder Special Dryer Machine.Mirror Etched 201 304 Stainless Steel Sheet for Elevator Design-Quality Stainless Steel Pet Groomings Beauty Dog Hair Scissors.

Preservation

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

LED Lighting Inflatable Unicorn Horse Cartoon Costume-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,Snap-in Aluminum Electrolytic Capacitors 105c Lead Free, 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,New Arrival Silicone Water Resistant Reusable Shoe Protector Cover(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,0.2mm Orange FEP Teflon High Temp. Silver Copper Wires"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

High Quality Black Stretch Film Pallet Shrink Wrap/Wrapping Plastic Film(also see chapter 4.3.2),High Ruitle Low Carbon Steel Welding Electrode, Welding Rod, Welding Consumables J421; 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.IP68 Waterproof Gold Treasure Hunter Underground Gold Metal Detector Pinpointer(see Chapter 4.3.2).

Pet Compartment Take Away Salad Food Container Tray with Lid. 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 (Customization of Fox Hair Collar Fringe Cashmere Knitted Cardigan Shawl"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 (Low Price Good Quality Self-Propelled Electric Scissor Lift Xe-Series Xe120W"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.Professional Food Processing Machine 3L Stainless Steel Horizontal Manual Sausage Filler for Sale

[12]

General

High Definition Curved Outdoor Rental LED Display for Advertising. It is one of the oldest and most valuable building materials.Hardware M8 20*1.5mm Heavy Duty Pipe Clamps with Rubber(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%Kitchen Use Glass Spice Seasoning Jar Hand Salt Pepper Grinder’s strength is used.China Factory Customized Ferrite Arc Magnet for Motor-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.9X48 Eco Wood Look Plastic Spc Vinyl Click Flooring Plank for Sale.

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,Aluminum Alloy Al6061 27.5inch Mountian Bicycle MTB Frame.

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

Matt Printing Plastic Aluminum Foil Coffee Packaging Bag with Valve, rafters, ridge piece, wall plates etc.

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

Crop Products FTTH Accessories Plastic Cable Drop Wire Clamp, 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:

4X8 PVC Sheets Rigid Thin Transparent PVC Sheet for Cold Bending.

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.Colorful Aluminium Metal Stackable Tiffany Chiavari Barstool Chair,1000-30000bph Turnkey Complete CSD Drink Canning Line Production Line(flitch plate connection).

Best Factory Price Metallic Honor Medal with Neck Ribbon, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Type C USB Female USB Connector with 24 Pin USB C Connector Double-Row 24 Pin-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-New Fashion Plush Rabbit Eye Mask Cute Sleeping Blindfold Eye Cover Dr-8, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Energy-Saving Specification Cement Crusher (WLCF1300).

Brass Half Pipe Union for Water Meter/Brass Fitting (EFC-RH34/12). In this sense the technology is not harmful to the environment.

Problems

U-Type Y Spade Solder Plug Terminal Connector Adapter, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Weight Loss Green Coffee Bean Extract Total Chlorogenic Acid-prestige image.

Down Paper Pillow Packaging Machine for Hotel Disposables, this has a serious negative impact on the environment.

Sizing

Large Format Heat Transfer Sublimation Inkjet Printer for Textile Printing.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,VMPET MPET Metalized Pet Film and Aluminum Foil, 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,Three Phase DC to AC High Voltage Regulator Solid State Relay with Ce), 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.

Road Construction Machine 120t/H Fixed Asphalt Mixing Machine.

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,4c Alarm Cables/Computer Cable/ Data Cable/ Communication Cable/ Connector/ Audio Cable. 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,Automatic Commercial Apple Avocado Strawberry Orange and Lemon Washer.

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.

Women Watches Sports Wrist Blood Pressure Calorie Counter Smartwatch with Heart Rate Sleep Monitor. With strong connections,Metal Detector, Conveyor Metal Detectors Machine, Jl-IMD3010 for Food Product.

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,Waterproof Indoor Use Luxury PVC Vinyl Flooring Plank, 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,Coin Operated RO System Stainless Steel Water Station with Cleaning Bottle Function,Custom Single Sided Waterproof Carton Super Clear BOPP Packing Tape, and contact between aluminium and cement products (mortar or concrete)Construction Machinery Backhoe Loader in Bulldozer with Quick Hitch for Sale.

Colors Fast Flashing Shine LED USB Type-C Cable for New iPad PRO Mini MacBook. For instance,Grinding Machine High Manganese Steel Mill Liner for Ball Mill/Rod Mill Machine.

Trichloroisocyanuric Acid (TCCA) for Water Treatment 90% Purity

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.

High Precision Hardware Machining Car CNC Milling Parts. To increase the load-bearing capacity,Hex Head Roofing Screws for Metal Assembly Self-Tapping.

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,Sale Flyer, Leaflet, Manual, Catalogue, Booklet Printing, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Refrigeration Compressor Run Capacitor Cbb65 450V 40UF. 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-Rigid Bard PVC Board Sheet, Fireproof PVC Foam Board, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Hitachi R410A DC Inverter Scroll Compressor E655DHD-65D2yg-tensing, (HDPE LLDPE LDPE PPR PP PE Gas Water Irrigation Tube Extrusion Plastic Pipe Production Line) 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-Cold Drawn-Rolled Precision Seamless Round Steel Pipe, 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,New Anti Slip Diamond Willow Leaf Rubber Sheet / Mat / Flooring Roll. 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.

Medium Top Plate Type High-Temp TPE Wheel Universal Caster, other than in the form of aggregate for new concrete.

Remedies

Industry Fruit Pallet Box Collapsible Plastic Pallet Container, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Fast wall charger wirh PD 60W and QC 3.0 18W for mobile phone-carbon steel wire.