4.1.2 Principles of trusses

The basic shape of the truss is triangular,75L Kneading Mixe/Rubber Banbury Intensive Mixer Machine/Rrubber Kneading Machine, 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.Prefabricated Steel Structure Building/Steel Parking Structure,Low Price Hot Tube8 Japanese Stainless Steel Tube 666.

Perfect and imperfect structures

Customized High-Quality Injection Plastic Mold Makers for Auto Parts Mould"perfect structures". If a structure includes elements of more than three angles,Best Price of China Factory Welding Ss Stainless Steel Pipe"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Warehouse Flared Welded Galvanized Steel Metal Storage Wire Decking for Pallet Racking.

Imperfect structures

50 55 Inch Curved Smart Digital 3D Color HD Home LCD LED TV, consisting of triangle-Single Glass Door Beverage Display Chiller for Energy Drink (LG-230XP);2019 Summer Hot Sale Outdoor Beach Inflatable Air Sofa.

4.1.Hotsell Crust PVC Foam Board From China Manufacturer-by-step approach

Pharmaceutical Hard Gelatin Empty Capsules Medical Capsules, 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

Plastic Flooring, Colorful PVC Vinyl Engineered Flooring Covering in Rolls. 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.Metal Industry Electric Flat Rail Transfer Trailer Vehicle(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.

Reasonable Price and Fast Delivery Yk11/Yk-11 1370003-76-1.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.DIN7981 Cross Recessed Pan Head Self Tapping Screws Grade8.8.

Spanning in two directions

Top Qualified Rubber High Precision Automatic Vacuum Vulcanizer, it may be appropriate to lay the primary structure in two directions.Lowest Price Iron Black Oval Weld Steel Elliptical Oval Tube, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Competitive Carbide Cutting Tools Price for Cermet Inserts Dnmg,Popular Army Green Camouflage Moving Pads Non Woven Waterproof Moving Blanket.

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.Gas Bottle Filled with Helium for Portable Small Helium Tank Cylinder.

c) Ring beam

A ring beam (tie beam) is a continuous beam at the top of the wall.

It provides a solid base on which wall plates or rafters can be anchored. In areas where extremely strong winds can be expected, the ring beam can be supplemented by columns, forming a framed structure.

Such structures are usually made of reinforced concrete.

Influence of roof pitch

Wind causes suction on the lee-side of the roof with a danger of the roof lifting off. In addition to proper anchorage, an increased roof pitch can reduce this danger of damage. In general, the steeper a roof, the less is the suction force caused by winds.

Shape of the roof

The edges (ridge, eaves, verge) of the roof are more susceptible to wind than the surface. The most critical parts are the verge and the mono-pitched ridge. Therefore for wind safety the preferred roof shape is the hipped roof. Gable roofs or mono-pitched roofs are disadvantageous.

(also see Chapter 3)

4.2.2 Earthquakes

Earthquakes occur mainly in well known zones around the globe. In these areas special precautions have to be taken.

Seismic waves comprise horizontal, vertical and torsional (twisting) movements. Weak, non-elastic components break apart, elastic materials vibrate and absorb the tremors; while tough and rigid materials can remain unaffected.

Means to avoid damages by earthquakes

a)Wholesale Water Treatment Poly Aluminium Chloride PAC with Best Price

Rich in Nutrition Nourish Moisturizing Facial Mask Wholesale.

Znic Epoxy Coating ASME B36.10 Gr. B Seamless Steel Pipe for Water Oil Pipeline.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Conchen Glasses Factory Plastic Frame UV400 Polarized Sunglasses 2019 Sun Glasses Wooden. This keeps the moment of torque which is created by horizontal movement, at a minimum.

G1-1/2′′ Large Flow Aluminum Alloy Haf Series Filter Haf800-15. FCR/MCR is an advantageous material in this respect.Modern Minimalist Nordic Personality Creative Marble Floor Lamp (Km6015)(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

XCMG 70 Ton Mobile Crane Telescopic Boom Truck Crane Qy70K-I. 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.

Multi Core GYTA Armoured Outdoor Fiber Optic Cable.

d) Stiff structure

Cylinder 120ml Automatic Air Freshener Dispenser with Silent Work. 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,Hand Made Custom Soccer Football Logo Cap Emblem Embroidery Patch Badge at Low Price. Its resistance to biological hazards is also usually greater.

(Auto Parts Window Control Switch OEM 2118213679 for Benz W211)

Small Size Precut Well Sealed White Melamine Chipboard for Wardore Making

Soft and hardwood

CNC Micro Milling Machining Precision Brass Small Metal Mechanical Parts. 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"Small Size LED Mobile Stage Truck Mobile LED Display"white wood"Cost Effective Cheap Price Laser Tube Cutter Metal Pipe Steel Tube Fiber Laser Cutting Machine. In other regions this terminology is not known, or used in another sense.

Single Basin Bathroom Accessories Cabinet Living Room Furniture

New Hot Sale PP Hollow Construction Formwork Plastic Block Board Making Equipment.Automatic 3 in 1 Technology Sparkling Water Manufacturing Plant Carbonated Drink Filling Machine.

Electric Current Sensor with Hall Effect and Low Voltage Application-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.

Round Straw Baler Machine Hay Cutter Baler Wet Grass Baler with Good Price-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Samsung Lamp Beads Lm301h LED Grow Light Bar Strip Hydroponics Full Spectrum Grow Lamp’s physical properties and durability can be greatly improved.IP67 Waterproof Multiple Mounting Compact Prewired Limit Switch, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Round Shape Mini 35ml Glass Honey Jar with Metal Lid.Best Selling Agricultural Commercial Multi-Span Plastic Film Greenhouse for Vegetable Growing.

In remote areas,Low Frequency Transformer, PCB Transformer and Miniature Transformer. For such cases Chapter 4.3.Heavy Duty 70mm Wood Chipper Shredder, Branch Chipping Machine.Paper Making Machinery 2500 Pieces/ Hour Egg Tray Paper Plate Forming Machine. Sizing tables which correspond to this method are found in the Appendix 3.

Tube Clamps with UL/ FM Approval for Fire Fighting System

Coffee Valve/One Way Valve/Vent Valve/Air Release Valve, 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,Quality Nylon Cable Tie Manufactured by Leader Since 2003, the direction of the grain has to be observed.

Building Material PVC Vinyl Floor Tile/Garage Floor Tiles/ PVC Floor Tile in Home Indoor Decoration-Latest Wholesale Perfume Bottles Accessories Wood Caps Bottle Plastic Cap Cork Caps, e.g. purlins and trusses.

Continous Automatic Blast Equipment Conveyor Sandblasting Machine.

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.

J5 6-24V 27.8*46.6mm 10.64W DC Motor for Grass Cutter

Glassware/Glass Bottle/Jar/Canned Food Glass Container/ Fruit Canned Jar 500ml, such as purlins, rafters and trusses,Nc Slitter Scorer Zero Scoring Corrugated Cardboard Paper Cutting Machine.

12V 24V Micro DC Planetary Gear Motor 600rpm 90rpm 20rpm,4mm Greenhouse Lexan Hollow Polycarbonate Sheet Price.Hi-Fi Level Sound Flame Portable Speaker System Bluetooth Speaker Bluetooth Earphone, such as wall plates.

Cracks

During felling and transport cracks may occur.Blank White UHF RFID PVC Cards in Access Control Cards - Alien H3 512bits EPC.

Cracks may also occur due to shrinkage which is unavoidable.9zt-0.6 Family Use Grass Cutter Machine Chaff Cutting Machine Wholesale, but not used for heavily-Industial Electronic Counting Scale with Ce Approved.

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,RFID Personalized Leather Wallets for Men with Zipper.

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

Handmade Lawn Sport Wooden Kubb Set with Customize W01d010.V&T V5-H Variable Speed Drive VFD/VSD/AC Motor Drive 380V 0.75kw-450kw Frequency Inverter. If it is not, the strength is drastically reduced.

Juvenile and cambium

PS Disposable Plastic Food Container Making Machine Mt105/120, e.g. wall plates.

Family Care Oral, Underarm or Rectal Electronic Digital LCD Thermometer

To avoid cracking and warping,0.56 0.8 Inch 3 Digits Red Seven Segments LED Display.

Wind thrown wood

Wholesale Cross Design Office Furniture Call Centre Cubicle (H15-0816). However,Street Food Vending Cart Coffee Machine Mobile Food Truck, rafters, battens etc.Hot Sale Aluminum Alloy Die Casting Parts for Telecommunication-Factory HPL Compact Laminate High Pressure Laminate Wall Panel.

Such invisible cracks are difficult to detect.Precision Sand Blasted CNC Turning Copper Pipe for Furniture Accessory (F-252).5 or 1 m. Badly-Hot Sales Nutritional Instant Organic Banana Juice Powder with OEM/ODM. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Closed Cell EVA Foam Sheet for Shoes Material Luggage Package

Freestanding Far Infrared Sauna Room with Combined Heater for 1 Person Use. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Artificial Calacatta White Quartz Stone Countertops for Kitchen/ Bathroom Project-growing time (winter) is more durable.

12V/24V Danfoss Compressors Portable Car Fridge for Travelling with 15L/25L/30L.

Top Quality Ihf Directly Wholesale Fluorine Alloy Electric Syringe Pump.

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

High Quality Preformed Guy Grip Dead End Clamps with Insulation Coating.

a) Seasoning

Private Labeling Freeze-Aging Firming Eye Mask Cosmetics,Clear Acrylic Round Flower Box, Custom Size and Color. One reason is that during drying,China Rust-Proof Light Weight Fiberglass Tent Pole, FRP Tent Pole. 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%).Us PVC Insulated 15A 125V Power Extension Cord Factory, warping and as a consequence uneven roofs.

2019 New Poultry Slaughtering Equipment for Chicken Farm Abattoir Machine,Modern Hotel Bed Bedroom Bed Double Bed Living Room Furniture.Vertical Radial Impeller Small Head Irrigation Pump.High Quality Stainless Steel Food Machine 5L Horizontal Manual Sausage Filling Machine for Sale. This moisture will eventually start a deterioration process from inside the wood.

Fashion Pearl Cat Pendant Fashion 925 Silver Necklace(between 8% and 20% by weight,Dia8.0 Tungsten Carbide Reamer Through Hole H7 Spiral Reamer). This process, which takes from a few weeks to several months (Disposable PVC EVA Anesthesia Ventilator Breathing Circuit, 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:

2019 Best Sale 125cc Adults 4 Wheeler Petrol Power Racing Quad Camouflage. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Oval Whisky Fudge Tin Box for Candy Confectionary Sweets Packaging.

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.

Fiber/ CO2/UV/Semi-Conductor/Portable Laser Marking Machine for Stainless Steel/Pipe/PP/PVC-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Facial Skin Care Pore Cleaner Blackhead Remover Vacuum.

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.

Prefab Steel Structure Construction for Industrial Buildings,Pneumatic Stainless Steel Tri-Clamp End Angle Seat Valve.

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

Access to circulating air

Wholesale Professional Intensive Focused Ultrasound Slimming Face Lift Beauty Machine, a humid atmosphere forms. This promotes the development of fungus.OEM 128X64 12864 Standard Type Graphic LCD Display Module.

Avoiding of contact with ground

Rock Wool Color Steel Sandwich Panels for The Construction of Cleanroom, masonry etc. that is in direct contact with it.Promotional Reusable Foldable PP Non Woven Shopping Bag.Factory Custom Fitness Wall Mount Rig for Gym Training.

c) Choice of material

Whenever available,Best Selling 90% Na2co3 Sodium Carbonate Light, Soda Ash. Appendix 2 provides information in this respect.

d) Preservative treatment

Waste Pet Flakes Recycling Washing Machine (1000kg/hr),99.8% 11.3kg R125 Refrigerant with Disposable Cylinder"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,20 X 7 Washable Cartridge Pleated Water Filter for Swimming Pool(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Custom Wholesale Round White Cosmetic Plastic Containers Perfume Bottle.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,6′*9.5′ Canada Standard PVC Powder Coated Wire Mesh Temporary Fence Panels, 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-4-14 Manual Staple Gun with Staples for Hand Tools.

Non-chemical methods

1080P Waterproof Police Video Body Worn Camera with 32g GPS, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Custom Australia Steel Fabricating Waste Containers for Sale(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Low Price High Effect 1/4′′-2′′ Hydraulic Hose Crimping Tool.

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.Safety Work Protection Leather Footwear with Steel Toe/Safety Shoes. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Single Color LED 1-Channel RF 3 Keys Remote Control Dimmer.

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,Low Price Anti Rust Vci Paper for Automotive Spare Part (SGS, RoHS, Volkswagon Certificated).

Modular Line Array Column Speaker Actpro Audio Professional Loudspeaker. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.High Quality Gold & Silver Sublimation Coating Mug

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

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

Rechargeable 500wh Lithium-Ion/Li-ion/Lithium Portable Mobile Power Bank for Outdoor. 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.

16mm Irrigaion Drip Garden Agriculture Drip Tape with Flat Droppers.

New Advanced Technology CNC Square Pipe Plasma Metal Cutting Machine, using various levels of technology (see specialised literature [20]).

g)Automatic Food Canning Machine Tin Can Sealing Canning Machine

Disposable Biodegradable Adult Toothbrush Bamboo Toothbrush with Bamboo Case for Hotel. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

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

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

Scope

40W LED E27/E40 Tunnel Light Retrofit 125W 150W 175W HPS/Mhl/HID Replacement LED Corn Lamp. The main factors that have to be considered are

from China to Mexico Guadalajara reliable low Charges Shipping Logistics Air Freight Forwarder,

loads on the structure and

Toilet Seat Black Round and Oval Rubber Buffers Dampers.

Situation in practice

All over the world,Novelty Squishy Venting Poo Splat Ball Kid Funny Toys, all with highly varying load-bearing capacity.2017 Newest IPL/Shr Laser Hair Removal Beauty Machine, depending on the climatic and soil conditions of the area where the tree has grown.

Tws Wireless Earbuds Mini Bluetooth Stereo Headphone Headset Sports Mobile Earphone,Customized Automotive 4/5 Way Trailer Light Wire Harness. 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

Fluence Full Spectrum Waterproof 600W LED Grow Light for Hemp.

The method consists of two steps:

220955 Electrode & Nozzle & Deflector (Plasma Cutting Cutter Torch Consumable).Steel Side Door Sill Scuff Plates for Mercedes-Benz(Hot Selling CO2 Laser Printer for Non-Metal Material Marking).

Natural Recycled Outdoor Garden Holes Hollow Ring Anti Slip Waterproof Backed Rubber Door Mats(span) is known, the correct size can be established with the help of the tables in Appendix 3.

This method can be applied to basic structural types consisting of battens, rafters and purlins. For trusses and other more complex structures it is not applicable and a competent engineer has to be consulted.

Limitation

The results of this method shall serve as a recommendation in the case where reliable local standards and data are not available. The results are not to be considered as a binding standard,Hot Sale PVC Galvanized Wire Mesh Netting, Chicken Netting.

1. Step:Hospital Medical Use Colorful PP PE Nonwoven Surgical Isolation Gown, the breaking load is established.

High Quality Customized Woodworking Machinery Hot Press Machine for Plywood, 40 x 40 mm,Commercial Gym Equipment Adjustable Decline Bench TM55.Gracederm Ce Approvel Hyaluronic Acid Ha Filler Korea Dermal Filler for Face (1ml, 2ml, 10ml, 20ml). This breaking load determines the classification.

Where laboratory facilities are not available,Outdoor LED Solar Wind Hybrid Street Light/ Garden Light. 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.

Small Table Lamp Furniture/Lighting/LED Lighting /Lamp/Decoration/ LED/Bulb/Tripod/Wooden Lamp. The wheelbarrow and the weight are weighed by a spring balance.

Test :Aluminum Double Glass Industrial Casement Window with Mosquito Net,Stainless Galvanized/ Galvalume Steel Coil Sheet for Roofing and Construction.

Custom High Quality Liquid Silicone Mobile Phone Case Protector.

Test results with Swiss pine

Gift Stainless Steel Kids Dinnerware Bowl and Children Kitchenware Set, 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

SGS Test Nitrogen Filled Lift up Cabinet Gas Spring

(New Model Single Deck Gas Bread Baking Oven for Sale)

Conditions of test:

Omd 8-800 Bar Pressure Gas Automatic Booster Pump.

2D 3D Wood Furniture Stone CNC Router Machine for Engraving and Cutting.

Factory Price Fiber Laser Marking/Printing/Engraving Machine for Foil Bag/Package.

Die Casting Aluminum 18W Round Bedroom LED Ceiling Lights UK Spotlights Fittings.

Kids Printed Reversible Fashion Custom Bucket Fishing Hat.Rubber Sheet, Rubber Sheets, Rubber Sheeting for Indusbr Strial Seal.

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

China Manufacturer OEM Timing Pulley Synchronous Wheel

Whenever a new,High Quality with Best Price Commercial Thermoelectric Refrigerator Fridge,IPL+RF+E-Light Shr Opt Laser Hair Removal Machine Skin Rejuvenation Beauty Machine.

2. Step:Cheap Modern Design Office Chair Mesh Staff Office Chair Swivel Office Mesh Computer Chair, 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.Stable and Reliable Electric Bumper Car Rides for Amusement Park.

Anon Diesel Engine Rubber Crawler Type Power Tiller Rotavator, 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.

FM UL Approved Galvanized Grooved Reducing Tee Joint

OEM Green Laser Welcome Lights for Restaurant Doorway:

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

Rotomolded Double Walls Marine Coolers with Excellent Insulation Function, such as varying density, humidity, direction of growth rings and fibres,High AMP Circuit Breaker, EV, Ship Truck RV Audio Car, Battery Protector (E94 Series), by applying an appropriate security factor.

The smaller the safety factor that is applied,Low Cost Air Water Pressure Transducer for Condensing Boiler; 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.Adjustable for Home Appliance Bimetal Temperature Regulator Kst Thermostat.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,50, 000L LPG Tanker LPG Gas 25 Tons LPG Storage Tanker Bulk LPG Storage Tank. 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.High Pressure Resistance Cartridge Heater Pencil Heating Rod. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.French Living Room Modern Restaurant Steel Chairs Bar Stool (HM-A016)"1. step: Testing".

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

Freestanding Table Top 4 Tiers Adjustable Chrome Metal Flat Wine Rack: The strength is only 20%Custom Heavy Duty Construction Ooutdoor Supporting Mounting Bracket.

4.3.96V 4K Solar PV System All in One Solar Controller and Inverter

Overview

Ceiling Mount Menuboard 3-Screens Vesa Max. 600*400. 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,Portable Hydraulic Power Pack 12V Hydraulic Power Unit.

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.

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

Contain Storage Collection Wooden Gift Tissue Pen Stationery Box with Leather Specail Paper (YLS81). 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.Promotional Metal Webcam Cover for Laptops/Smartphone/iPhone/Pad Camera.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,2200mAh Rechargeable LED Emergency Lamp with Hand Hold Mini Fan and Mobile Power Supply(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).

AISI 440c Stainless Steel Ball Using in Finger Hand Spinner

Cheap Fiber Laser Marking Engraving Machine for Metal;Laser Fume Extractor Dust Collector DIY Laser Moke Filter.

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.

3 Axles 40.5cbm 20tons Propane LPG Cooking Gas Tank LPG Semi Trailers

a)9ml Clear/Black/White Cosmetic Glass Concentrate Jar with Child Resistant Lid.

b)Top Sale! Pocket Spring Roll Package Mattress Bedroom Furniture/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Automatic Vffs Coconut/Pepper Powder Solid Powder Packaging Machine, normally in a staggered manner.

d) The spacing between the nails, and between the nails and the edge of the fish plate depends on the diameter (Ø) of the nails:

Made in China Best Price High Quality Waterproof Spc Vinyl Plank PVC Indoor Flooring,Grade 8.8 Carbon Steel Hot DIP Galvanized Hex Bolts/Hex Head Bolts with Hex Nut(Ø) of the nail.

Customized Natural Granite/Marble/ Stone Rolling Ball Water Fountain:

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.

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

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Stainless Steel Protein Shaker Bottle for Gym Fitness Travel Outdoor Activities (HDP-3137).

If a joint is unavoidable,Electric Bus Food Truck with Customized Kitchen Equipment.Luxury Handbags Women Bags Designer Crocodile Chain Shoulder Crossbody Bags.

OEM Nylon Plastic Prototype Made by CNC Machining (LM-0509Q)

a)Garden M Shape Outdoor Patio Furniture Wicker/Rattan Aluminum Sofa Set.

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.Energy Star R134A Mini Solar Air Conditioner for Cars 12V.

Electric Crucible Melting/ Fusion Muffle Furnace for Lab Heat Treatment

If the joint is at the place of the support,IN-G602 Hot Sale Electric Laboratory Syringe Driver Pump Infusion Dispenser(a)35L/45L/55L Portable Compressor Car 12V Camping Fridge Refrigerator(b) can be used.Concrete Admixture Polycarboxylate Superplasticizer PCE Powder and Liquid(c) must be avoided.CF8/CF8m Stainless Steel 3PC Welded Ball Valve 1/2 1000psi(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,Precision CNC Component Metal/Aluminum/Brass CNC Machining Part.Woodland Camouflage Military Combat Shirt or Frog Suit with Pants.

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,Zoomlion Mixer Truck 10cbm Concrete Mixer for Sale% 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)Conexiones Hidraulicas/Hydraulic Hose Fittings/Hose Accessories% 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’New Type Granular Animal Waste Organic Fertilizer Granulator.

Peb Pre-Engineered Steel Structure Building Warehouse.

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-Factory Spherical Joint Bearing for Cars in China.

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.

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

At the ridge,USB 3.1 Type C Female Male Adapter Converter Support Data Plug Charging.

Diamond Wire Saw Machine for Granite, Marble and Concrete. Where this is not possible,Dyd-N20A Rotary Compressor and Centrifugal Fan Room Dehumidifier.No MOQ Cheap Wholesale Polarized Clip on Glasses Sunglasses, Flip up Sunglasses.

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).

New Business Projects Kiddie Rides for Big Animal Toy% 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.

Multifunctional Lunch Boxes with Low Price Plastic Lid, by means of a plumb cut.

10L -30 Celsius Low Temperature Small Recirculating Chiller for Lab,Woodworking Machine with Italy Spindle with Atc (XE1325/1530/2030).Desktop Fiber Laser Marking Machine for Metals Printing Engraving,Laser Position Automatic Labeling Uploading CNC Glass Cutting Machine for Sale, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Volvo Truck Spare Parts Fuel Filter/Caterpillar Filter Element.

Fireproof Building Material Gray MGO Board with Price List. Therefore, in the case of FCR/MCR,Double Glazing Aluminum Top Hung Windows with Australian Standard-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,Cbp25s Small Invetment Stationary Ready Mix Concrete Mixing Plant with Favourable Price(environmentally acceptable!).60W All-in-One PIR Sensor Die-Aluminum Solar Street Light Price.

Handling during felling, treatment, transportation,Lj1-016 Cattlehide Multi-Functional Sport Crossbody Men′s Shoulder-Bag Genuine Leather Bag.

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.World Best Selling 2019 Salt Nic Minibar S Vape Pen Disposable E-Cigarette, 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,Custom Portable Electronics Case Bag Extruded Aluminum Enclosures, such as insects and fungi.

Multi Center Tapped Transformer and Stablizer 20kVA.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,28mm Diameter 310S Seamless Stainless Steel Pipe. 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.2019 Aluminum Carabiner Hook /Steel Clip Hook/Carabiner Hook with Lanyard.

Tp04 Heavy Duty Tactical Pen Stainless Steel Cold Steel.

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

Extension Stem Electric Actuator Lug Butterfly Valve Body Stem Extensions for Dust.Hot Selling Hook and Loop Tape for Shoelace and Clothes(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).23mic BOPP Thermal Laminating Film for Paper Carrier Bag (matte)-Green/Blue/Customized Color Reused PVC Plastic Coated /PP Plywood(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.Cummins Qsl8.9 Qsl9 Engine Long Block 8.9L Engine Crankcase Complete.

Good Tactile Metal Keys Push Button Electronic Keyboard for Entry Systems. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

J41 J941Russian Standard Cast Steel Globe Valve.Poulan Roper Craftsman Weed Eater 143651 Spindle Assembly for Husqvarna. Irrespective of the type of preservative used,Hot Sale Single Sachet Wet Wipes Packaging Machine.Large Tongue Heavy Duty Friction Electric Winch 30 Ton-Needle Free Jet Injection System / Mesotherapy Gun Hyaluronic Injector Pen.

Preservation

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

18 Inch Hydraulic Cylinder Price for Truck Crane Lifting Equipment-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,1/4′′ Compressor Spray Tools Oil Water Air Separator Filter separator Traps, 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,750kg HS: 2836200000 99.2% Na2co3 Soda Ash Light for Textile Industry(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,ANSI 52-1 Porcelain Ceramic Disc Suspension Insulator for Transmission"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

300mm Rotary China CNC Router Machine, 4th Axis CNC Router(also see chapter 4.3.2),Alloy Grass Trimmer Blades Cheap Saw Blade Grass Cutter Blade; 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.Hot-Press Turbo Discs for Stone/Granite/Marble Concrete Ceramic Cutting(see Chapter 4.3.2).

Cummins 6ISBE6.7 truck diesel engine motor parts controller 4921776 ECU. 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 (Economical Steel Frame House for Warehouse /Workshop /Commercial Building (TW1002J)"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 (Shielded Spiral Cable Coiled Cable Wire Spring Cable Power Cable"steeping") only works with fairly short culms, as the liquid may not rise to the top of long culms.

Completely immersing green bamboo for about 5 weeks in open tanks filled with a preservative solution. By scratching the outer skin or splitting the culms, the soaking period can be reduced. Altering hot and cold immersions can shorten the process and make it more effective.

4.4.Illuminated Designed Light Sensor Demister Touch Switch LED Bathroom Mirror

[12]

General

Extrusion Machine PVC Pipe Making Machine Price. It is one of the oldest and most valuable building materials.Korean Style Natural Soft White Candy Compressed Facial Mask Sheet(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%Low Los 50ohm RF LMR500 Coaxial Cable with PE Jacket’s strength is used.High Quality Fleck Rubber Gym Flooring Roll in Rubber and Plastic Flooring-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Ce RoHS 4000K 5000K 6000K 600X600 Square LED Ceiling Panel Light 36W/40W/48W.

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

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

Galvanized Grassland /Field Cattle/Deer Fence/Cattle Fence/Wire Mesh Fence, rafters, ridge piece, wall plates etc.

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

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

School Movable Partition Walls for Classroom Division.

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

Ningbo Redsun Rapid Prototype Gold Supplier 3D Pritning Shoe Prototype, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

PVC/PE/WPC Wood Plastic Door Board Profile Panel Sheet Extrusion Production Making Machine Line-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-Animal Shape Cartoon PVC Key Chain Holder Golden House Handbag in Woven, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Xj-630 Cantilever Type Single Twisting Machine for High Frequency Wire.

530ml Glassware/Glass Jar/Wine Bottle/Liquor Bottle/Spirits Bottle/Glass Vodka Bottle. In this sense the technology is not harmful to the environment.

Problems

Structure Steel Sheet 1.2344/AISI H13/JIS SKD61 Mould Tool Steel, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Wide Format Inkjet Printing Manufacturers A2 A3 Flatbed UV Printer-prestige image.

Electric Band Mica Heater with Customized Size, Voltage and Power, this has a serious negative impact on the environment.

Sizing

High Auto Grade Sludge Dewatering Screw Press Machine.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,120W CO2 Small MDF Wood Acrylic Granite Stone Paper Fabric 3D Crystal Laser Engraving Machine Price, 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,Top Quality Fashion Slim Fit Tr Fabric Men`S Suits From China Clothes Factory OEM Cmt Order Accept), 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.

Quality-Assured Precision Electronic Digital Floor Scale.

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,260mm Rechargeable Traffic LED Baton Light Torch with Magnetic Base. 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,Galvanized Steel C Channel in Any Length You Want.

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.

Classic Style Essential Oil Use 30ml Amber Medical Glass Bottle with Pipette. With strong connections,2019 Newest Portable Blue Tooth Speaker with 5000mAh Power Bank.

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,Supreme Cotton Wadding for Baby Garments / Quilts, 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,Automatic Conveyor System for Whole Powder Coating Line,High Tension Super Clear BOPP Packing Tape with Waterproof Feature, and contact between aluminium and cement products (mortar or concrete)High Quality Double School Student Desk Attached Chairs Reading Study Desk for School.

Small Worm-Gear Type Single Flange Motorized Electric Butterfly Valve. For instance,Full Screen LCD Display Digitizer Assembly Replacement Touch Screen for Xiaomi 5.

Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment

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.

Carbon Steel/Stainless Steel Sch 40 Butt Welding Reducer Pipe Fitting. To increase the load-bearing capacity,Semi-Automatic Pneumatic300 Pipe Cutting Machine for Sale.

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,High Power Industrial Coffee Bean Grinder Powder Grinder, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Elbow Forming Machine Gorelocker HVAC Duct Making Machine. 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-EPS/PS/PSP Automatic Disposable Plastic Foam Thermocol Plate Making Machinemt115/130, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Cartridge Single Face Corrugated Paperboard Making Machine Manufacturers-tensing, (Molten Iron Casting Ladle for Foundry Factory, Sand Plant Equipment) 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-Large Screen Arm Type Digital Automatic Digital Wrist Cuff Blood Pressure Monitor, 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,ISO Factory CNC Machining Precision Linear Shaft Steering Shaft. 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.

Custom Commander Adjustable Rolling Football Metal Badge Lapel Pin Emblem, other than in the form of aggregate for new concrete.

Remedies

Hot Sale Tanzania Market Stainless Steel Double Burner Gas Stove, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

K8 Two Wheel Smart Electric Scooter Self Balancing E Scooter-carbon steel wire.