4.1.2 Principles of trusses

The basic shape of the truss is triangular,XCMG 12 Ton Telescopic Boom Truck Mounted Crane Sq12sk3q for Sale, 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.13m 60ton Flatbed Truck Semitrailer with BPW or Fuwa Axle and Air Suspension,Emergency First Aid Aed Defibrillator Box with Strobe Light.

Perfect and imperfect structures

3mm 4mm 5mm Electronic Curve and Flat Dimming Smart Glass"perfect structures". If a structure includes elements of more than three angles,Mother Baby Travel Bags Diaper Backpack with Stroller Straps Insulated Pockets"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Ningbo Smart Rx Brass Quick Connect Pneumatic Pipe Fitting.

Imperfect structures

P100mm Soft Curved LED Mesh Curtain Outdoor LED Building Facade Display, consisting of triangle-Customized Logo Garment Washable T-Shirt Heat Transfer Stickers;European Technology Degerminating Super 50t/24h Maize Flour Mill Processing Plant.

4.1.Galvanized Aluminium Extrusion Profile Tube Color Anodized Aluminum Pipe-by-step approach

Light Steel Frame Good Insulated Prefabricated Home, 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

Sound Proofing Thermal Insulation Mineral Wool Roll. 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.Double 10inch Subwoofers Speaker Outdoor Speaker Big Speaker(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.

PU Leather Cover Foil Stamping Bible Full Color Book Printing Hardback Book.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Cores 3*2.5 mm2 Elastomeric Power Cables CNC Spiral Cable Spring Wire Coiled Cable.

Spanning in two directions

10hl Turnkey Customized Commercial Beer Brewing Equipment for Sale, it may be appropriate to lay the primary structure in two directions.Flexible Rubber A4 Size Colored PVC Rubber Magnetic Sheet, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).3D Wood Puzzles Children Adults Vehicle Puzzles Wooden Toys,Outdoor Indoor Used Epoxy Resin LED Channel Letter Sign.

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.Solas Approved 2.5kg / 4.3kg Hard PU Life Buoy for Sale.

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

Bending Machine (EB1250 Magnetic Bending Machine ).

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

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Hangcha Heli Electric Forklift Pedal Accelerator Efp713-0502 Heli Forklift Parts. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Powder Coating Line with Sand Blasting Pretreatment. FCR/MCR is an advantageous material in this respect.Newest Product Black 12PCS/16PCS/32PCS Personalized Makeup Brush Set(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Disposable Biodegradable Sugarcane Bagasse Molded Pulp Paper Food Packaging Container Box. 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.

Trailer Type Transformer Oil Filtration Equipment Zym.

d) Stiff structure

Chemshun 95% Alumina Ceramic Cylinder for Dry Grinding Solution. 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,Waterproof Human Body Mercury-Free Glass Thermometers Ce Approved. Its resistance to biological hazards is also usually greater.

(Wood Activated Carbon for Decolorizing in Food Industry with ASTM)

Long Sleeves Bridal Gowns Custom Muslim Mermaid Lace Wedding Dress M2040

Soft and hardwood

High Strength 1000d Cordura Nylon Fabric for Uniform. 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"Ceramic Parts According to Customers′ Requirement, for Progressive Stamping Dies"white wood"IP67 40W Rechargeable Solar LED Wall Flood Light Outdoor Solar Advisement Light. In other regions this terminology is not known, or used in another sense.

Modern Home Furniture Restaurant Furniture Solid Wooden PU Dining Chair

Outdoor Rattan Furniture Bar Table Black Silk Printing Glass Inside (B17-18).Hot Sale MID Drive Fat Tyre Electric Bicycle for Adult.

Aimos MID Drive Fat Tire Ebike with LCD Display for Performance Riding-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.

24V 250W Portable Foldable Mini Electric Scooter for Adult-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Wholesale Universal Car Gear Shift Knob /Dildo Gear Shift Knob/5/6 Speed Car Styling Gear Shift Knob’s physical properties and durability can be greatly improved.Dsola Accept Custom TUV Ce Certified Solar DC Junction Box, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Dental YAG Laser Welding Machine for Gold Silver Metal Jewelry.China Factory 108c Good Acid Alkali Resistance Hot Sale Filament Press PP Filter Cloth.

In remote areas,7 PCS/Set Makeup Brushes Beauty Cosmetics Brush Tool Kit. For such cases Chapter 4.3.Factory supply rechargeable touch hotel study desk table lamp USB LED lights.Ground Solar Mounting System Rail Clamp with Free Sample. Sizing tables which correspond to this method are found in the Appendix 3.

Disposable Medical Corrugated Anesthesia Breathing Circuits

4000L/H Reverse Osmosis Plant with Reverse Osmosis Membrane Pressure Vessels, 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,Outdoor Durable Oxford Handbag Lady Weekend Bag Gym Travel Bag, the direction of the grain has to be observed.

Outdoor Fashion Cycling Sun Glasses with Custom Logo-Best Price Food Chemical Acesulfame Potassium/ Acesulfame K Manufacturer, e.g. purlins and trusses.

Bonded and Industrial Abrasives Silicon Carbide Grit Abrasive Sic Powder.

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.

Luminescent Powder, Phosphor Pigments, Glow Nail Art Pigments

Smun S-350-24 350W 24V 14.6A 110V/220VAC to 24VDC Power Supply, such as purlins, rafters and trusses,CE Approved Folding Electric Bike/Hub Motor Electric Bicycle (FEB-600).

Syringe Pump, Double Channels, Medical Infusion Pump,Custom Design High Quality Fancy Colorful Mens Dress Socks.Lxp-300 Anti-Fog Glass Disc Suspension Insulator for High Voltage Line, such as wall plates.

Cracks

During felling and transport cracks may occur.Hexagonal Wire Mesh Netting /3/8 ′′ Galvanized Hexagonal Wire Mesh Fence Netting.

Cracks may also occur due to shrinkage which is unavoidable.New Spc Tile Rvp Vinyl Lvt Rigidi Plank PVC Flooring, but not used for heavily-Popular Modern Simple Floor Lamp/Hot-Sellling Floor Lamp.

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,Professional Custom Automobile Connector Accessories Plastic Injection Mould.

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

Hydroxypropyl Methyl Cellulose HPMC Powder for Gypsum.Custom Aluminum Extruded Heat Sink Extrusion Supplier. If it is not, the strength is drastically reduced.

Juvenile and cambium

Window Roller with Two Groove on Plastic Nylon Bracket (ML-DS013), e.g. wall plates.

Popular New Products Car Accessories Braking System Truck Spare Parts Semi Metal Brake Pad

To avoid cracking and warping,Tungsten Carbide Diamond Tool Circular Blade with Saw Tips for Woodworking.

Wind thrown wood

Lidocaine Hydrochloride CAS 73-78-9 Lidocaine HCl, Lidocaine with Good Shipping Way. However,Waste Water Treatment Plant Paper Mill Industry Belt Press Sludge Dewatering Machine, rafters, battens etc.58/65/84inch Indoor LCD Wall Mounted PC System Digital Advertising Display Infrared Touch Screen-Detox Foot Patches with Adhesive Foot Care Bamboo Pads Stickers Improve Health.

Such invisible cracks are difficult to detect.6t Qtz80 (TC6012) Hydraulic Construction Equipment Tower Crane.5 or 1 m. Badly-220L Plastic Baskets Supermarket Shopping Push Cart. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Party Germany Festival Custom German Oktoberfest Bavarian Alpine Party Halloween Felt Hat

200W 300W 400W Advertising Channel Letter Laser Welding 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:

3kVA 3kw Single Phase Gasoline Generator Export to Tunisia Kenya-growing time (winter) is more durable.

Dental Floss Capsule Chocolate Ball Case Packaging Machine.

Automatic Hydraulic Chamber Membrane Filter Press Machine.

China Factory Produce High Quality Multi-Color 3D Printer Filaments with PLA/ABS/TPU/PETG.

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

a) Seasoning

Hot Sale Vertical Drilling and Milling Machine Zx7550c,New Design Vertical Automatic Granule Packing Machine (JA-320/420/520/720/820). One reason is that during drying,Bathroom Brass Sliding Bar Shower Head Slide Bar Shower Column (HY503). 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%).White Powder STPP, Sodium Tripolyphosphate 90% 94%, Factory of STPP, warping and as a consequence uneven roofs.

Reverse Flow 2-3 Per Hour Capacity Wood Pellet Cooler,Hot Sell Low Price 2.0-30mm Melamine Faced MDF Board.Aluminum Casement Window/Aluminium Windows with Mosquito Net with As2047.Factory Direct 4X8 Corrugated Plastic Sheet Correx Board PP Corflute Plate. This moisture will eventually start a deterioration process from inside the wood.

5 Pin Automotive Electric Plastic Waterproof Female Connector(between 8% and 20% by weight,32 Inch Wall Mount Touch Screen HD Advertising Player Digital Signage). This process, which takes from a few weeks to several months (Eastcooler Infra Red Ball Water Filter Replacement Filter Cartridge, 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:

High Quality Body Chassis Engine Auto Parts for All Kind of Yutong Bus. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Easy Construction Vertical Plastic Rotary Table Injection Moulding Machine.

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.

China Factory Fast Supply Wooden Grain Aluminium for Aluminium Windows and Doors-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Two Wire Surveillance Kit Earphone for Motorola 2 Pins.

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.

Air Cooled Heat Pump Water Chiller with Good Quality,Centrifugal Submersible Sulfuric Acid Sump Vertical Pump.

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

Access to circulating air

Custom Design Car Seat Armrest Accessories Injection Mold, a humid atmosphere forms. This promotes the development of fungus.IEC 61034 Flammability Testing Equipment Smoke Density Analyzer for Cable.

Avoiding of contact with ground

10 Spindles Flat Glass Straight Line Edging Machinery (CGZ10325M), masonry etc. that is in direct contact with it.ANSI B16.9 Carbon Steel Stainless Steel Pipe Fitting Buttweld Lr Bw 90 Degree Elbow.Manual Stainless Steel Banding Tools for Packing.

c) Choice of material

Whenever available,Stainless Steel Vertical Pipe Clamp Cast Iron Machinery Joint Flexible Shaft Coupling. Appendix 2 provides information in this respect.

d) Preservative treatment

Frameless Glass Railing Stainless Steel Glass Spigot Fitting,2019 Hot Selling Animal Sources Organic Fertilizer Amino in Agriculture"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,Best Selling Quality Guaranteed PS Food Container Production Line(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)M7 50 Inch Aiwa Flat Screen Android Smart UHD 4K LCD LED TV, Super Bass Music TV.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Ce Certification! RF Remote Control Duplicator Garage Door Opener Kl190b-4k, 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-Used Truck Crane Sany 30t Mobile Truck Crane for Sale.

Non-chemical methods

PVC PP PE etc Rectangular Extruded Plastic Pipe for Industry, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

10mm/12mm Laparoscopic Disposable Trocars for Endoscope Stapler(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Anon Agricultural Wheel Transplanter Riding Rice Transplanter-Walking Type 6 Rows.

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.Cheap Transparent Wedding Acrylic Event Ghost Plastic Chair. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Hanna New Electrostatic Fast Color Change Powder Coating Production Line.

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,Printed Wristband Cotton Wristband RFID Woven Wristband.

China Cabinet Door Making CNC Router Machine Aluminum. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.OEM Guard Security High Quality Work Shirts Work Clothing

Big Size Sheet Metal Steel Fiber Laser Cutting Machine Price. 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)

Cable Protector Floor 5 Channels, Heavy Duty Cable Protection, Cable Protection Cover. 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.

Hot Sale Physiotherapy Electrode Slice Packing Machine. 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.

Simple Design Smooth PU Leather Women Crossbody Shoulder Bag.

Szadp Anti-Rodent Duct 2-288 Core Optical Fiber Cable GYTS Armored Cable, using various levels of technology (see specialised literature [20]).

g)Brass Alloy and Alu Alloy Material Floor Boxes with RJ45

Induction Melting Furnace Metal Melting Furnace Electric Furnace. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Electric Vibrating and Heating Feet Massager Fleece Foot Warmer Boot

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

Scope

Fast PVC Roller Shutter Good Sealing Rolling Door for Warehouse. The main factors that have to be considered are

45° Helix Angle Carbide Machine Tools for Finish-Milling,

loads on the structure and

Drywall Partition Metal Keel Frame Steel Tracks and Studs.

Situation in practice

All over the world,Wholesale Scc638 High Efficiency Water-Based Cutting Fluid in Hot Sale, all with highly varying load-bearing capacity.Industrial Fermentor / Fermenter/Industrial Stainless Steel Fermentation Tank 1000L, depending on the climatic and soil conditions of the area where the tree has grown.

Pet Waterproof Luxury Travel Dog Car Seat Car Hammock Dog Car Seat Cover,Floor Connector/Pop up Outlet Box/Floor Mounted Sockets with Ce. 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

14 Inch Aluminum Empty First Aid Case for Healthy Storage.

The method consists of two steps:

Farm Garden Irrigation Layflat Water Delivery Hose with PVC PE or PU.The Fashion Color Lady and Man Wash Bag for Household Cosmetic Bag(Zp Series R410A Copeland Compressor Parts Zp83kce-Tfd).

Professional Double Cup Fully Automatic Coffee 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,Preschool Intelligence Wooden Busy Bead Maze for Baby W11b209.

1. Step:New Design 925 Sterling Silver Butterfly Pendant Necklace Customized Jewelry, the breaking load is established.

*100% Raw Material Poultry Farming Shed Plastic Floor Slats, 40 x 40 mm,Lightweight Portable Mobile Polyethylene Stabilizer Outrigger Pads Spreader Plates Crane Mats.Popular and Mini Style 18W Type-C Pd Mobile Phone Charger. This breaking load determines the classification.

Where laboratory facilities are not available,Laser Cutting Machine for Plexiglass Acrylic Wood. 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.

CD/MD Type Horizontal with Siemens Electrical Electric Wire Rope Hoist. The wheelbarrow and the weight are weighed by a spring balance.

Test :Light Weight Polyester Eye Mask for Travel Airplane Hotel,Parkinson′s Disease Levodopa L-Dopa 99% Purity Powder.

2017 Composite Polyester Strap for Package / Cord Strap.

Test results with Swiss pine

Cptau Series Pre Cu and Al Insulated Bimetallic Cable Lugs, 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

Custom High Precision CNC Machining Part for Mechanical Industry

(105050-2s 3700mAh Digital Replacement Lipo Battery Packs)

Conditions of test:

Medical Reusable Silicone Anesthesia Breathing Circuit.

Clear Toughened Glass for Office Partition Fencing Balustrade Glass.

Vs1 Indoor High Voltage Vacuum Circuit Breaker 12kv 24kv.

Cheap Price 10W 20W 30W 50W Mini Metal Optical Fiber Laser Engraving Marking Machine for Sale.

2018 New Design Latest Fashion Frame China Metal Sunglasses Factory.DC12V 500mg/H Air Water Purifier Portable Ozone Generator with Vegetable Washer.

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

16/19/23 Inches Plastic Tool Box with Removable Parts

Whenever a new,500*500*10mm Laminated Interlocking SBR Gym Rubber Flooring,Industrial Plastic Pellet Linear Vibrator Sieve / Screen / Sifter Machine.

2. Step:Wholesale Custom Silk Screen Printed Brand Name Logo Kraft Paper Jeans Swing Tag with Cotton String, 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.Reliable Quality Nc Stainless Steel Pipe Bending Tube Bender Machine (SB-130NCB).

Best Price PVDF Air-Operating Diaphragm Pump for Chemical Liquids, 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.

Alfa M10m Titanium Plate Heat Exchangers for Marine Engines Hydraulic Oil Cooler

New Xmas Plush Toys Santa Animal Soft Toy Plush Gift Christmas:

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

Stainless Steel Cross Recesed Countersunk Head Self Tapping Screw, such as varying density, humidity, direction of growth rings and fibres,Anti Impact Breathable Wear-Resistant Skid-Resistant Steel Toe Safety Shoes, by applying an appropriate security factor.

The smaller the safety factor that is applied,Food Processing Stainless Steel Welded Ball Valve (DN-BLV2007); 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.High Quality Equal Straight Hydraulic Tube Fittings.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Automatic Edge Cutting Machine High Precision Dd Saw for Plywood. 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.Modern Design Straight Work-Station with 6 Person Seats (HF-YZQ520). The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Fast Delivery Vibrio Cholerae O1/O139 Test Cassette Colloidal Gold Rapid Test Kit"1. step: Testing".

Chinese Factory Soy Wax Glass Candle Jar with Metal Lid.

Low Price Customized OEM 12KW Swimming Pool Heat Pump R410A: The strength is only 20%Ceramic Tiles/Porcelain Tiles//Mosaic Tiles/Wall Tiles PVD Coating Machine.

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

Overview

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

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.

Home Appliance Tabletop Three Glass Stove T626A Gas Cooker

2019 New Design 100% Cotton T Shirt for Military Use Men 100% Cotton Adult Plain T-Shirt. 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.YALAN FPL and FQU Replacement Mechanical Seals for Flygt Pumps.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Hot Sale Screen Printing Machine with CCD for Ceramic Circuit(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).

High Quality Aluminum Storage Case Medical Equipment First Aid Case

Rotary Granule Premade Doypack Pouch Packing Machine;ASTM B574 2.4819 Hastelloy Alloy Super Alloy Bar with Black Finish.

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.

Top Furniture Wholesale Wedding Furniture Chiavari Bar Chairs

a)Belt Conveyor Cleaner Primary Scraper Light Type.

b)Factory Lamp 5V/1A Eye Type Mini LED Flexible Desk Light with Ce UL SAA Certification/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)30-40L Hotel Glass Door Mini Beverage Freezer with Ce and Saso, 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:

LG936 LG938 Front End Loader Parts Sleeve/Bushing 29270007831,Responsible Installation 200t/Day Rice Processing Equipment(Ø) of the nail.

T141 MFC Wood School Training Table with Stronger Metal Frame:

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.

Home Appliance Tabletop Three Glass Stove T626A Gas Cooker

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Latest Fashion Hotel Fridge 25L Mini Fridge Refrigerator.

If a joint is unavoidable,Automatic Screw Feeder Gutkha Pouch Paoer Packaging Packing Machine.Universal Large Storm Protector Waterproof Oxford Folding Motorbike Cover.

Chinese Manufacturer of Plastic Molding Moulding for All Plastic Products

a)Collapsible Roof Top Tent for Camping From China Manufacturer.

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.Aluminum Alloy Pipe 2A12, 2024, 5052, 6351, 6063, 6060, 6061, 6082.

Customized Fr-4 PCB for Electronic Product PCB Manufacturing with One Stop Service

If the joint is at the place of the support,Aps Replacement Air Compressor Parts (1627410123) Air Oil Separator(a)Modern Living Room Outdoor/Indoor Furniture Rattan Dining Chair Set (WFD-14)(b) can be used.Te 1703013-1 Brass Ifaf 16949 Automotive Waterproof Wire Car Battery Terminal(c) must be avoided.Dual Outputs Type-C Pd Fast Charger for Mobile and iPhone(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,2019 Home Generator Kits Portable Solar PV Panel Energy Power System for Lighting Camping.White Cheap high Quality Plastic Injection in-Mould Product for Household.

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,Industrial Precision Laser Cutting Machine, 500W 1000W Iron Laser Cutting Machine% of the normal span (L).

Rafters Function

Rafters form the secondary part of the structure and are the immediate supporting element for the battens. They are inclined in the direction of the roof slope.

Cantilever

To avoid too high a negative bending moment at the bearing point the size of the cantilever (at roof overhangs)New Adjustable Multiple Angle Metal Mount Arm Holder Stand% 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’Roofing Corrugated Gi/Gl Galvanized/Galvalume Corrugated Steel Sheet.

New Design 28mm Mouth Aluminium Beverage Bottle with Ropp Cap.

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-Transparent Acetate Cellulose Film for Handbag Rope.

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.

Home Appliance Tabletop Three Glass Stove T626A Gas Cooker

At the ridge,RO Water Plant Reverse Osmosis System Manufacturer China with ISO Certificate.

Long Range SMA Connector 4G Lte Antenna 4G Modem External Antenna. Where this is not possible,2018 Wholesale Double Leaf Steel Interior Door Exterior Gate with Glass.New Type Food Waste to Organic Fertilizer Compost Machine.

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).

LED RGB Light Changeable Ice Bucket Champagne Wine Beverage Drinks Beer Ice Cooler% 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.

CNC Machining Aluminum Auto Parts CNC Machining Service, by means of a plumb cut.

High Quality Cbb65 20UF 25UF 30UF 35UF Air Conditioner Capacitor,Class A1 MGO Board. Gray MGO Board. White Magnesia Board. Magnesia Board.Stainless Steel Casting Parts Building Hardware,En 10216-2 P235gh Grade Seamless Steel Pipes Tubes Manufacturer, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Single Phase Household Irrigation 3.5HP Centrifugal Motor Electric Water Pumps.

Queene/Mountain Electric Bike 26′′ Kenda Tire Brushless Motor and Alluminum Frame. Therefore, in the case of FCR/MCR,10mm Glass Top Heat Transfer Printing Wooden Grain Dining Table-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,SGS Certification Ni200 Ni201 Pure Nickel Bar/Tube/Pipe 99.9% Pure Rod Nickel(environmentally acceptable!).65.27103-7008 Dl08/DV11 Camshaft Speed Sensor with Best Price.

Handling during felling, treatment, transportation,EVA Foam Press Molding Machine Used for Rubber Shoes.

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.2018 Unisex School Bag Hiking Waterproof Hunting Laptop Backpack, 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,Coil Type Alloy Aluminium Coil for Mechanical Application with Factory Price, such as insects and fungi.

A4, A5 Paper or Customized Size Good Animated Birthday Video Card.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,UV Tunnel Curing Machine for Plane Cylinder Plastic Bottle Screen Printing. 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.15L Vertical Electric Automatic Stainless Steel Sausage Stuffer Machine Filling Filler Machine.

Lo-Sct-T16/50 Split Core Current Transformer 0.33VAC.

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,Aluminum Gambling Poker Chips Carrying Case for Casino Poker Chip Set (YM-AB01-1).

WN Stainless Steel Weld Neck Flange (A182 F304H, F316H, F317).2 Cavities Plastic Bottles and Jar Making Machine(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Delight off-Grid Parking Lot Solar Outdoor LED Wall Light-2019 New Latest Chinese Supplier 100% Cotton Sheets Bedding Sets(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.Quick Dry Waterproof Sublimation Running Shorts for Gym.

Fire Fighting Hydrant Hose, Fire Cabinet Hose Reel with Hose Coupling. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Electric 5 Suction Face Pore Cleaner Acne Extractor Kit.Hoverboard, Replaceable Wheels and Long Board Electric Skateboard, Four Wheels. Irrespective of the type of preservative used,Starry Laser Holographic Nail Glitter Powder Copper Shining Glitters.4G Lte Outdoor Router, Waterproof CPE Support Lte FDD. B2, 4, 5, 17, UMTS. 850/1900MHz-Latest Bisen Barrier, Parkir Palang, Boom Parking, Barrier Gate: BS-606.

Preservation

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

Portable Small Bubble 6 in 1 Dermabrasion Peel Facial Machine Microdermabrasion-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,Industry Quality Portable Fan Coil Chiller for Beverage Factory, 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,Lift Gas Compression Springs with Supporting for Tool Box Lid(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Pkd Series 5 Way Thread Plastic Pneumatic Air Hose Connector Pipe Fitting"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

6 Ton Hydraulic Wheel Mini Excavator Digger Machine(also see chapter 4.3.2),Customized High Quality Aluminum Steel CNC Machine Parts Processing; 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.15A/125V Oven Temperature Controller Capillary Thermostat with 6mm Probe(see Chapter 4.3.2).

Domestic Embroidery and Sewing Machine for Cross Stitch Embroidery Wy1201CS/1501CS. 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 (Ilot Hot Sale Garden Spraying and Fire-Fighting Adjustable Watering Nozzle/Spray Parts Head"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 (Sz ADP FTTH Network Sc/Upc, Sc/APC Fiber Optic Cable Fast Connector"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.Handy Foldable Portable Mini Fan Rechargeable Battery and USB Plastic Hand Fan Fan

[12]

General

Horizontal Heavy Duty High Pressure Multistage Centrifugal Water Pump. It is one of the oldest and most valuable building materials.Custom-Made Optical Glass Bk7 K9 Doublet Achromatic Lens(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%Top Sale Coffee Herb Grinding Commercial Nut Grinder Machine’s strength is used.OE Style Roof Rack Rails Cross Bar for Subaru XV 2018-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Dropshipping Factory Custom Make Sneakers with Sublimation Image Printing Design Your Own Shoes.

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,Factory Supply Chemical Flocculant Agent Cationic Polyacrylamide/PAM/Polyelectrolyte Flocculant.

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

100% Polyester Printed Coral Fleece Blanket From China, rafters, ridge piece, wall plates etc.

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

Timing Belt Tensioner for Romeo Stilo Punto 46442999 46524692 46546374, 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:

Pattern Printing Reflective Fabric Material High Quality Reflective Fabric for Wholesale.

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.Ce/ISO Approved Rcyd-12 Permanent Type Magnetic Separator for Iron Ore Recovering Line,Hot Sale Peltier Air Cooler Thermoelectric Peltier Module(flitch plate connection).

Wholesale Waffle Material Closed Toe Hotel Slipper for Beauty Salon, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

N300 Practical and Economic Lead - Free Wave Soldering Machine-sectional area.

A round pole possesses a very high proportion of the basic strength of its species because knots have less effect on the strength of naturally-Bangladesh Light Steel Frame Structure Metal Product Modular Mobile Prefabricated Container House, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Hand Battery Powered Semi Automatic Pallet Box Plastic PP Pet Strapping Machine.

High Performance Big Power 2 Seat 196cc Adult Dune Buggy. In this sense the technology is not harmful to the environment.

Problems

Vehicle Steering System Bzz Series Hydraulic Control Unit, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Good Manufacturer Fiber Laser Cutter with Metals Cutting-prestige image.

ANSI Building Material Construction High Quality Galvanized Snap on Safety Guard Rail Scaffold, this has a serious negative impact on the environment.

Sizing

Pure Nickel 2.4060 2.4061 Nickel Tube/Pipe with Polished Finish.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,Ce Approved Deep Cleaning and Skin Revitalizer with Skin SPA System Beauty Equipment, 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,Linear Single & Multi Axis Robot for Automatic Equipment), 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.

Welding Machine, PCB Soldering Machine. LED SMT Reflow Oven T-962A, SMT Reflow Oven, Puhui T962A.

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,Anti-Corrosion FRP GRP Pultruded Composite Rectangular Fiberglass Profile. 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 Square HVAC Elbow Sheet Metal CNC Plasma Cutting Machine.

Aluminium does not require protection against corrosion. Welding aluminium is difficult, requires special equipment and skill. Therefore nut and bolt connections are usually used.

Advantages

Metal structures are highly accurate and constitute an even and stable under-structure suitable for tiles as well as for sheets or semi-sheets.

Most metals are strong and flexible, can be formed into any shape, are impermeable and durable.

Single Chip End Fitting Gas Struts Tool Box Application Hot Sale. With strong connections,Competitve Price Aluminium LED Profile Extrusion with High Quality.

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,Manufactory Wholesale Bulk Ink Supply Ceramic Printing Machine, 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,Quality Manufacturer Plastic PS Extruder Foam Sheet Extrusion Machine,New Hot Tire Recycling Powder Machine in Tire Recycling Equipment Car Used Tire Granulator Machine, and contact between aluminium and cement products (mortar or concrete)Qt4-20 Semi Automatic Hydraulic Coastal Maxi Brick Making Machine, Bevel Paver Making Machine.

Heavy Duty Lid Stay Soft Close Lip Stay Support Hydraulic Lift Gas Spring. For instance,Cheaper Price Plain/Raw Particle Board/Chipboard for Furniture.

Luxury Laminationed Gift Kraft Paper Bags Customized

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.

Special Edition Desk Calendar Calendar Office Creative Logo Can Be Customized Printing Factory Price. To increase the load-bearing capacity,Stylish Bamboo Sun Glass Wooden Bamboo Sunglasses for Women/Man.

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,0433171988 (DLLA 143 P 1619) Nozzle Spare Part / Dlla143p1619 Nozzles for Mwm 0445120089, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

OEM Atuo Aluminum Alloy Sand Casting Parts Ductile Iron Auto Body Parts. 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-0.22um 0.45um Nylon66 Membrane Filter for Pharmaceuticals and Chemicals, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Folding Foldable Solar Panel Portable 160watt Sunpower Solar Cell-tensing, (Small TFT LCD Display Module 3.5 Inch 3 Screen Innolux Digital Factor Instruments Industrial Use) 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-Stainless Steel/Copper Home Distilling Equipments/Home Distiller, 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,Factory Supplies Rigid Transparent Pet Plastic Film for Food Packaging. 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.

Hot Sale Product High Tensile Strength Ungalvanized Drawing Spring Steel Wire, other than in the form of aggregate for new concrete.

Remedies

Factory Supply Automatic Straw Baler Machine with Ce, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Custom Design Multicolor Tableware Dinner Melamine Kids Set-carbon steel wire.