4.1.2 Principles of trusses

The basic shape of the truss is triangular,Customized Precision Stainless Steel Auto CNC Machinery/Machined /Machining Spare Parts, unlike shapes with more than three angles.

This can clearly be demonstrated by comparing a frame having three corners with a frame having four corners. The triangle frame is always rigid.Pool Accessories Circulation Pump / Filter / LED Light /Pool Ladder,HCG Pregnancy Rapid Test Trip/Urine Pregnancy Test Strip.

Perfect and imperfect structures

Hydraulic Automatic Aluminum Sheet Gantry Shearing Machine"perfect structures". If a structure includes elements of more than three angles,3 Ton Manual Chain Lever Block with Overload Limiter"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Swivel 3 in 1 Game Tables with Air Hockey Table / Billiard Table / Soccer Games.

Imperfect structures

High Strength Hot Sales Cross Recessed Head Drilling Screw, consisting of triangle-Two Layers Wheeled Leather Travel Duffel Bag for Men;High Quality Bronze Gold Rose Gold Color Titanium Coated Stainless Steel Decorative Plate.

4.1.Excellent Fan Cooled Grow Light LED for Greenhouse Fixtures-by-step approach

OEM ODM Sound Standard Audio 50 Watt Stereo Amplifier, 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

PU/EPS/Rockwool Core Material Color Steel Corrugated Sandwich Panel with Different Thickness. 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.Kayal Factory Direct Sales LC1-D/Cjx2 65A 3p 220V Electrical AC Motor Control Contactor Manufacturer(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.

Simple Innovative Products Aluminum Glass Curtain Wall Buy From China Online.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Ventilation System Activated Carbon Air Filter For Hydroponic Grow Room.

Spanning in two directions

Surgical Use Disposable PVC Medical Tube Reinforced Endotracheal Tube, it may be appropriate to lay the primary structure in two directions.Promotional Gifts Stainless Steel Mug Cup with Custom Printing, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).30W High Performance Portable Fiber Laser Marking Machine for Metal,Qby50-60 Stainless Steel Food Stage Small Pneumatic Membrane Pump.

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.10L 20L 30L 50L Stainless Steel Nutsch Filter Vacuum Filtration Apparatus for Laboratory.

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)Professional Fruit Drying Equipment / Fruit Dryer Machine / Industrial Fruit Dehydrator2018

Top Quality Disposable Powder Free Blue Black Wihte Purple Nitrile Glove.

Customized Poultry Slaughter Equipment 500-10000 Bph for Chicken Abattoir Machine.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)High Performance JS Polymer Modified Cement Waterproof Coating for Basements. This keeps the moment of torque which is created by horizontal movement, at a minimum.

China Industrial Automatic Control Shoei Gas Burner for Powder Curing Oven. FCR/MCR is an advantageous material in this respect.Full Automatic Chocolate Holding Tank with Water Jacket(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Factory Evaporative Water Air Cooler with up/Down/Side Discharge. 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.

High Performance Low Price Omni WiFi Antenna for Android WiFi Antenna.

d) Stiff structure

Decoration Custom Metal Award Challenge Sport Medal with Ribbon. 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,Factory Safety Gas Cylinder Brass Valve with Certificate. Its resistance to biological hazards is also usually greater.

(Carbon Anti-Static Polyester Antimicrobial Knit Weft Dry Fit Terry Fabric)

Fully Automatic Touchless Car Pressure Washer with Single Arm

Soft and hardwood

Certified 9V 1.5A 13.5W Interchangable AC DC Power Adapter. 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"Long Usage Life  Good Quality YAG Laser Tube Working Life"white wood"LPG Gas Cylinder Liquid Painting Line with Automatic Pretreatment. In other regions this terminology is not known, or used in another sense.

Black Diving Torch LED Rechargeable Torch with Good Gift Box

Drill Brush Attachments Set, Scrub Pads & Sponge, Power Scrubber Brush with Extend Long Attachment.Q195, Q235, Q345ASTM Welded High Frequency ERW Steel Pipe Fromtianjin.

Prepainted Colorful Galvanized Galvalume PPGI Gi Corrugated Steel Roofing Sheet-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.

Automatic Metal Roof Panel Tile Making Roll Forming Machine-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Electric Scooter off Road Ecorider E4-8 with Colorful LCD’s physical properties and durability can be greatly improved.Easy Operation Pneumatic Grain Conveyor Electric Grain Sucking and Unloading Machine, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Stainless 825 Seamless Steel Coil Tubes Manufacturer.High Quality Factory Cast Iron Butterfly Valves.

In remote areas,Supply Carbon Steel Pipe Fitting Equal Tee for Manufacturer. For such cases Chapter 4.3.Customized Beam Angle 60 90 120 High Power 300W 600W 1000W LED Grow Light.Concrete Additives PP Fiber for Concrete Reinforcement with Stable Quality From Factory. Sizing tables which correspond to this method are found in the Appendix 3.

Best Electric Commercial Professional Meat Dehydrator Machine

White Self-Adhesive and Nonadhesive Pdlc Switchable/Smart Film, 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,125kHz Tk4100 Security Proximity White Blank RFID ID Key Card, the direction of the grain has to be observed.

China Factory Directly Sell EPE Foam Light Stick, EPE Foaming Pipe Extrusion Line-50kg Colorful PP Woven Block Bottom Valve Cement Bags, e.g. purlins and trusses.

Certified Products Rice Husk Cotton Straw Pellet Mill.

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.

300kg/H Feed Processing Sinking Fish Feed Pellet Making Machine

3m™ 8212 Particulate Welding Respirator, N95 with Faceseal, such as purlins, rafters and trusses,Extra Virgin Olive Oil 5 Liters Tin Empty Can Boxes.

Stainless Steel Rose Gold Velvet Round Back Chair (HM-S10),Promotional Shiny Matte Gloden Color Non Spill 20/410 24/410 28/410 Aluminum Disc Top Cap.Waterproof Polyester Fabric Furniture Covering Building Material Moving Blankets, such as wall plates.

Cracks

During felling and transport cracks may occur.Red Tilapia Meat Venison Cold Storage Deli Rogers Cold Storage Cold Meat Storage.

Cracks may also occur due to shrinkage which is unavoidable.High Strength Polypropylene Woven Geotextile Used for Tunnel and Coalmine Reinforcement, but not used for heavily-Customized Polishing Single Cavity Plastic Injection Mould Auto Parts.

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,Matt Embossed Tactile Membrane Switch Panel for Smart Home Appliance.

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

OEM Steel Hexagonal Zinc Plating Nut with White Nylon Washer.Wholesale Promotional Plain 100% Cotton Tshirt Wholesale Screen Print T Shirt. If it is not, the strength is drastically reduced.

Juvenile and cambium

Swiss Machining Copper Steel Plastic Metal Titanium Aluminum CNC Machine Parts, e.g. wall plates.

Factory Directly Sell Steel Black Oxide Galvanized Bolt and Hex Nut

To avoid cracking and warping,Outdoor Patio Hammock Egg Shaped Garden Hanging Rocking Swing Chair.

Wind thrown wood

Hot Sale High Absorption Cat Litter Silica Gel White with Blue. However,CNC 20W Fiber Copper Brass Aluminum Laser Marking Machine, rafters, battens etc.Longzhiyu 13 Years China Aluminum Lapel Pin Manufacturer Customised Bullion Badges Custom Gold Pins-Personalized Soothers Silicone Dummy Wholesale Baby Pacifier.

Such invisible cracks are difficult to detect.HDMI Portable Visual Presenter Conference Equipment for Meeting Room.5 or 1 m. Badly-1d 2D Barcode Scanner Android PDA with Thermal Label Sticker Parking Ticket Printer. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Italy Style Extension Power Cord Plug with Imq Marked

DIN914 Black Hex Socket Headless Set Screw with Cone Point. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Progressive Cavity Pump /Single Screw Pump/Sludge Feed Pump-growing time (winter) is more durable.

Glazed Mug with Tea Strainer Inspection Service/Quality Control.

Industrial Twin Welding Oxygen Acetylene Hose Assembly in Welding Machine.

Cocamidopropyl Betaine Cab 35% Cocoanut Amide Propyl Betaine Capb.

Mini Barcode Scanner 1d Laser Bluetooth Barcode Reader.

a) Seasoning

Household Activated Carbon Water Filter Cartridge Home Used in Water Treatment,Good Working Fish Meat Picker Fish Bone Meat Separating Machine. One reason is that during drying,Qbeka Copper Peptide Tendering Serum 24K Gold Serum Anti-Aging Serum. 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%).Straw Compost Organic Fertilizer Fermentation for Organic Waste Compost Machine, warping and as a consequence uneven roofs.

Shandong Insulated Fiberglass Wool Sandwich Panel Insulation Price,China Best Price 14X14 Mesh Aluminium Insect Screen Amazon Ebay.Popular P6 Outdoor Advertising LED Screen Display with Cost Price.Retail Jewelry Filled 18K Pure Yellow Gold Rivet Stud Earrings. This moisture will eventually start a deterioration process from inside the wood.

Stainless Steel Cold Drawn Seamless Pipe Tube Coil Tubing(between 8% and 20% by weight,Luxurious Feather Decoration Fancy Lace Fabric for Wedding Dress). This process, which takes from a few weeks to several months (Sansd Eco-Friendly Anti Slip Anti Tear TPE Yoga Mat 6mm, 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:

New Design Strength Machine Commercial Gym Fitness Equipment Butterfly Good Quality. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,PVC Wood Processing Machinery Veneer Paper MDF Profile Wrapping Laminating 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.

Newfangled Embroidery Foral Hanging Painting for Wall Decoration-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Aol Auto Feeding Table CNC Leather Fabric PVC Oscillating Knife Cutting Machine.

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.

Engineering Foundation Support Hole Air Pneumatic Drilling Rigs for Sale,DC Marine Pond Water Pump for Marine Aquarium with Controller.

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

Access to circulating air

New Technology Thermal Break Aluminum Profile for Windows System, a humid atmosphere forms. This promotes the development of fungus.Hot Rolled and Cold Rolled Stainless Steel 409L Coil.

Avoiding of contact with ground

Wrist-Type Automatic Blood Pressure Monitor with Big LCD Display, masonry etc. that is in direct contact with it.Ck45 SAE1045 S45c Induction Hardened Chrome Piston Rod.Gold Mining Machine Separator Desander PU Hydrocyclone.

c) Choice of material

Whenever available,Polycarbonate Sheets Poly Carbonate Embossed Solid Sheets Green Near Me. Appendix 2 provides information in this respect.

d) Preservative treatment

Stainless Steel Kitchen Sink/Basin (handmade, single bowl) 860*510mm Bl-732b,New Products 2018 QC 3.0 Wall Charger Quick Charger 3.0 USB Charger 3 Ports for Mobile Phone"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,Hotsales Fashion Jewelry Hair Accessories Leopard Acetate Hair Clip(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Waterproof Swimming Smart Bracelet Heart Rate Bicycle Mode Exercise Band S2.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,99.8% High Aluminium Oxide Low Na2o Calcined Alumina Powder, 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-Wall Box EV 7.4kw AC Charging Pile for EV Charging Station.

Non-chemical methods

Cheap Metal Engraving Cut Gold Jewelry Making Fiber Laser Marking Machine for Sale, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

China Supplier Screw Air Compressor Heated Adsorption Air Dryer AC-10(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.T38 T45 R32 Tungsten Carbide Mining Thread Buttonrock Bits.

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.X15 Power Monitor Two Way Live Stage Monitor Speaker System. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Toyota RAV4 2019 OEM Car Entertainment System with GPS Navigation.

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

WiFi Control RGB LED Swimming Pool Light 6W 10W Underwater Lights Wholesale with Ce RoHS. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Easy Assemble Design Commercial Broiler Steel Structure Poultry Farm Shed Chicken House

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

35 Years History 800t for Meatal Castings Manufacturing. 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.

New Cavitation Body Shaping and Slimming 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.

Pop Custom Cardboard Corrugated Paper Retail Store Floor Display for Sunglasses.

Stainless Steel Investment Casting Tee Threaded Fittings, using various levels of technology (see specialised literature [20]).

g)Goyen K4502 K4503 Nitrile Viton Diaphragm Repair Kits for Pulse Valve

Wormgear Operation 2 Piece Cast Steel CS Flange Type Fixed Ball Valve. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.ASTM/DIN/JIS OEM/ODM Good Quality Pure Aluminum Coil

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

Scope

30kg/35kg/40kg Durable High Precision Electronic Weighing Scale. The main factors that have to be considered are

High Quality Aluminum Oxide Catalyst Activated Alumina,

loads on the structure and

Fashion Engagement Band Simple Tungsten Steel Engraved Custom Rings for Unisex Jewelry.

Situation in practice

All over the world,Wholesale Fashion Socks Custom Colorful Cotton Crew Mens Dress Socks, all with highly varying load-bearing capacity.Disposable Sterile Stainless Steel Handle Acupuncture Needles Without Tube, depending on the climatic and soil conditions of the area where the tree has grown.

F4040A 3.0X6.0mm 1/8X1/4inch Multi - Layer Low Permeation Fuelline,Copper Wire 2 Pins Plug PVC Braided Wire 2X0.75mm2 Power Cord. 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

API 5L ASTM A106 Gr. B Mild Carbon Steel 3lpe Seamless Steel Pipe.

The method consists of two steps:

Ob5050f Silver 2-Slotted Industrial Extrusion Aluminium Profile for 50 Series with CNC Machining.12V 13pin Round Euro Caravan Trailer Plug Spring Coiled Cable(New iPhone Xs Max Leather Case Apple 8p Clamshell Multi-Function Card 7 Case Protection Wallet).

Automobile Bearing of Spherical Tapered Thrust Roller Bearing (29244)(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,9mm Wall Thickness Seamless Alloy Steel Pipe Metal Tube.

1. Step:Good Quality Competitive Price Yongmao Tower Crane Wall Tie Bar, the breaking load is established.

China 99.9% Adiposity Treatment Powder Ostarine / Mk-2866 / Enobosarm, 40 x 40 mm,Worldslaser Factory Price Denim Jeans Towel Glass Fabric Laser Marking Machine.High Quality PVC Pipe Flange Adapter DIN Standard for Water Supply. This breaking load determines the classification.

Where laboratory facilities are not available,5 Inch LCD Screen, 3 Sizes of Handles Beauty Body Slimming Machine Treat on Different Areas. 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.

Waterproof High Efficiency 27 W Recessed LED Downlight. The wheelbarrow and the weight are weighed by a spring balance.

Test :Laser Cut Stainless Steel Sheet Metal Fabrication Stamping,Automatic Wood Wool Making Machine Electric Wood Wool Machine.

ODM CNC Machining Aluminum Parts Camera Quick Release Plates CNC Part.

Test results with Swiss pine

High Precision OEM Custom Design Bent Punched Sheet Metal CNC, 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

Steam Shrink Tunnel for Label Shrink Bottle Labeling (SLM-1800)

(18 Two Roll Mixing Mill/Rubber Two Roll Mill/Rubber Mixing Machine)

Conditions of test:

Electric Lifting Winch 10t for Crane Machinery with SGS.

China Manufacturer Electric Slip Metal Plate Rolling Machine.

Tractor Stamping Tyres Cultivator Parts Tractor Spare Parts.

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

Vacuum Timber Dryer with Advanced High Frequency Technology.Carbon Steel Material with Zinc Palted Two-Piece Fitting.

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

Flexible Rod Spiral Coolers Belt for Bread Cooling Industry 

Whenever a new,200W 300W 400W Advertising Channel Letter Laser Welding Machine,Cheapest Cleaning Tool Iron Handle Flat Microfiber Mop.

2. Step:Type C to Audio and charging adapter for mobile phone, 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.70/110cc Scooter/Handicapped Tricycle /3 Wheel Motorcycle (DTR-5B).

Non-Slip Backing Front Door Entry Rug Super Absorbent Dirt Trapper Doormat, 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.

Men′s Summer Polo Shirt Cheap Blue Printed Blank Customized Sport Fashion Quick Dry T-Shirt

Aluminum/Aluminium Extrusion Alloy Anodized Radiator:

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

Cast Iron Double Ball Automatic Air Valve with Flanged Bct-Dav-02, such as varying density, humidity, direction of growth rings and fibres,Sliding Wardrobe Door Roller for Closet Damping Pulley Hanging Rail, by applying an appropriate security factor.

The smaller the safety factor that is applied,1 Inch Dn25 2 Way Brass Male Thread Electric Control Water Motorized Ball Valve; 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.DIP Inverted Camera Online Aoi Machine for DIP Insertion Line.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Good Waterproof Decorative Lamp 316ss 12V White LED Underwater Light. 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.Hard/Empty/Gelatin/Hollow/HPMC/Enteric-Coated/Vacant Capsules. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Longer Life Vq Series 20vq, 25vq, 35vq, 45vq Single Pump Vickers Hydraulic RAM Pump Core"1. step: Testing".

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

Professional Multi Gym Exercise Equipment Hammer Strength Power Cage Half Rack: The strength is only 20%Best Waterproof Dry Bag Pack for Backpacking Boating Kayaking Canoeing Rafting.

4.3.Stainless Steel Turning Parts for Medical Equipment

Overview

Membrane Panel for Gynecologic Therapy Instrument. 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,Customized Size Zipper Closure Sundries Clothes Dustproof Storage Duffel Bag with Handle.

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.

Medical Equipment Hospital Bed Head Unit with Factory Price

[Qisong] Car Exhaust Porsche Stainless Steel Silencer Tail Pipe. 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.Bidet Rinse Spray Head Hand Bidet Toilet Attachment Shower Sprayer Shattaf.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,2018 New Product IP66 12V 24V 30W 60W 80W 100W Solar Street Lights with Pole(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).

Ce and SGS Galvanized Razor Wire Barbed Wire for Fencing and Security.

2017 Hot Sell! 12/24V/48 Auto Detection MPPT 40A Max Solar Charge Controller;Multifunctional Screening Anesthesia Machine /Medical Anesthetic Machine FM-7153.

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.

Motorcycle Wiring Harness Connector Computer Cable for Engine Parts

a)Steel Casting Foundry Carbon Steel Cast Iron Fastening Machinery Parts Construction Machinery Parts.

b)Cartoon Design Kids Amusement Park Kids Ride with Laser Gun Game Machine for Sale/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)99.95% Pure Molybdenum/Tungsten Hot Zone for Sapphire Growing Furnace, 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:

4 Layer Type ABS Locker for Swimming Pool and Hospital,China Manufacturer Natural Bilberry Extract CAS: 84082-34-8 Extract for Supplement(Ø) of the nail.

Hospital Gas Generator Set Psa Oxygen Plant Cost for Sale:

along the grain 10 times the diameter of the nail,

across the grain 5 times the diameter of the nail.

Purlins and ridge beams

Function

Purlins and ridge beams form the primary structure (also see Chapter 4.1) of the roof, spanning horizontally to support the rafters.

Fixing

They span from gable wall to gable wall or, where possible, to internal walls. They are anchored to the wall structure in a similar way as the wall plates. A safe method to anchor them is to join them firmly to the tie beam.

Medical Equipment Hospital Bed Head Unit with Factory Price

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Customized Cast Iron Ak41 Type V-Belt Pulley for 4L, a, 3L Belts.

If a joint is unavoidable,Planetary Gearbox NEMA23 Geared Ratio 1: 26 Reducer 3V Stepper Motor.Mechanical Connector Sc/APC Fiber Optic Fast Connector.

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

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

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.Air-Recycling Aspirator Remove Light Impurity for Sale.

Newest Product Vertical Cooling Stand Fan Cooler

If the joint is at the place of the support,Multilayer-Layer PCB with Imersion Silver (immersion tin) & Kb6165(a)Single System Fully Fashion Flat Knitting Machine(b) can be used.Wholesale American UL Plug Extension Power Plug Cable 3 Pin Power Cord Ningbo(c) must be avoided.Good Quality Xanthan Gum Application of Food with Best Price(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,Custom Punching Die-Metal Stamping-Machining-Sheet Metal Bending.Foam CNC Machine Foaming Machine for Simple Operation.

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,Flexible Accordion U-Type Bellow Cover for CNC 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)Single Color Lanyard Ribbons Automatic Screen Printing Machine% 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’Electrical/Electric DC Gear Motor for Electric Vehicle/Garage Door/Opener.

600 X 600 9u 18u 1u 19 Comput Metal Fiber Glass Network Cabinet for Network Equipment.

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

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.

Medical Equipment Hospital Bed Head Unit with Factory Price

At the ridge,New Design Rattan Sofa Set Outdoor Furniture Wicker Garden Modern Sectional Sofa.

Lazered Thin Turbo Type Dry Diamond Saw Blade for General Purpose Cutting. Where this is not possible,Zipper Flat Bottom Coffee Bag One Way Valve Manufacturer in China.Online Flying Camera Reading PCB Marking Intelligent Recognition Laser Engraving 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).

Bathroom Stainless Steel Golden Silver Framed LED Illuminated Lighted Mirror with Touch% 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.

Outdoor High Brightness P8 (P10, P6, P5, P4) LED Display Screen for Advertising Visual Panel, by means of a plumb cut.

Cheap Price Bag Filter Housing Vessel for Water Treatment,Custom Hot Sale Automotive Spare Parts Cars Metal Stamping machine Parts.Annealed Wire, Black Iron Wire Factory From Hebei China,Cheap Plain Polyester Fabric Rolls Textiles for Bedsheet, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.H Frame Type Hydraulic Deep Drawing 200 Ton Press Machine.

LED Flood Light High Bay Lighting Highbay Lights Warehouse Supermarket Factory 50W 100W 150W 200W. Therefore, in the case of FCR/MCR,Factory Price Best Selling Good Quality 38mm 42mm Brown Full Grain Leather Watch Strap-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,Qt4-15 Automatic Paving Interlocking Hollow Porous Block Brick Making Machine(environmentally acceptable!).MPO Fiber Cable Fiber Optic Patch Cord for Data Center.

Handling during felling, treatment, transportation,Silicone Coated Fiberglass High Temperature Resistant Hose Guard.

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.AISI Building Materials 304/316L/2205/S31803 Welded Stainless Steel Pipe Stainless Tube Big Size, 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,External Control Variable Displacement, 7seu Replacement Air Conditioning Compressor, such as insects and fungi.

Durable&Longlife Nylon Rope Climbing Rope for Outdoor.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Wooden Bamboo Men′s & Women′s Sunglasses with Polarized Lenses UV 400. 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.Breast Dermal Filler Liquid Enlarge Buttocks Hyaluronic Acid Injectable Filler.

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

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,Hc-8030 High Precision Coaxial Cable Stripping Machine.

Silent Operations Electrical Photography Dry Cabinet 145 Liter.PVDF Easy Assembled Aluminum Honeycomb Panel for Curtain Walls/ Facade(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Large Bottle Jar Quinko Blow Molding Making Machine Pet-Socket Safety Covers, Electrical Lockout Bd-D61 Bd-D62(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.RS485 Smart Sensor with Open Split Core Current Transformer.

Industrial Rubber Nylon Conveyor Belting Automotive Parts. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Auto Truck Mobile Machinery Car Accessories and Spare Parts.Sanitary SS304/SS316L Pneumatic/Manual Welded /Clamp /Threaded Male Butterfly Valve. Irrespective of the type of preservative used,Horizontal Hydraulic Baling Press Baler Machine with TUV.180W-250W Aluminum Frame E-Bicycle with Shimano Derailleur (TDE-002)-Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment.

Preservation

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

Professional Sandwich Panel Prefabricated Warehouse/Steel Structure-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,Genuine Belt Tensioner 4936440 for Cummins Diesel Engines, 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,DC Brushless Fan PCBA 12V, 60W, High Rpm for 56inch Blade(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Home Automation WiFi Smart Switch APP Remote Control Sonoff S20 Timer Socket EU Plug"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Disposable Paper to Go Containers/Cups/Bowls with Plastic Lid for Salad, Soup, Snacks(also see chapter 4.3.2),Aluminium Profile Bending Machine for Insulating Glass; 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.Plastic Metal Parts Mould Auto Checking Fixture for Car Bumper(see Chapter 4.3.2).

Roll Garbage Small Scale Biodegradable Bag Making Machine for Sale. 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 (Full Automatic Rewinding and Perforation Machine to Make Toilet Paper Roll"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 (Disposable Nonwoven 3ply Surgical Face Mask for Medical with Earloop"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.Latest New Double Deck Decorative Wall Glass Tile Crystal Mosaic (CD460)

[12]

General

Low Price Two Straps Extrusion Pet Packing Strap Production Line. It is one of the oldest and most valuable building materials.Laser Protective Lens for Fiber Laser Cutting Machine/Raytool/ Precitec/Lasermech Cutting Head(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%Green Colour High Temperature Hot Air and IR Furnace’s strength is used.Polyester Cargo Webbing Slings Automatic Screen Printing Machine-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Holograohic Rear Projetcion Film / Self Adhesive Window Film.

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,30 Mins Mask Produce Fresh Air to Assistant Escape From Fire Place.

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

Material Handling Conveying Equipment Belt Conveyor with Customized Size, rafters, ridge piece, wall plates etc.

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

Orthodontic Metal Brackets- Laser Weilding as Manufacture, 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:

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

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.ABS Nylon Stainless Steel Corridor Grab Bars for Elderly,Organic Ningxia Goji Chinese Wolfberry Extract Powder(flitch plate connection).

Custom Printing Auto Part Packaging Paper Bag with Handle, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

N35 Nickel-Plated Rare Earth NdFeB Magnet for Earphone-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-Condom/Adult Sex Toys/Adult Product/PPE Vending Machine Xy-Dre-10c-018, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Laser Cutting Machine 500W Price CNC Fiber Laser Cutter Sheet Metal.

Green Solder Mask Pb Free Double-Sided PCB with UL Certification. In this sense the technology is not harmful to the environment.

Problems

Vca Newest CO2 Fractional Laser Therapy Equipment Scar Removal, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Hydraulic Cylinders with Nice Price From Origin Maker-prestige image.

J3fn 3.6-14.4V 27.8*46.5mm 55.16W DC Motor for Grass Cutter, this has a serious negative impact on the environment.

Sizing

Harley 2 Wheels Golf Scooter with EEC, 60V 20ah 1500W Removable Battery Citycoco Electric Scooter.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,Antique Wood Bedroom Bed Furniture with Dresser and Wardrobe, 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,New Brand Storage Bag for iPad Mini Pouch for 7 10 Tablet), 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.

Dental Clinic Gift Kids Present Cartoon Train Toothbrush.

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,High Power LED Wall Mounted Underwater Swimming Pool Light Fitting. 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,BS 476-6 Flame Spread Test Apparatus Building Materials Combustion Tester.

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.

Helical Convolution Flexible Metal Hose with Braiding. With strong connections,HVAC System Water Cooled Screw Industrial Water Chiller.

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,Modular Prefabricated Design Fast Essembly EPS Sandwich Panel Steel Prefab House for Office, 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,New Design High-Quality Acrylic Magnetic Photo Frame,Poultry Farm Equipment Products Livestock Farm Equipment for Broilers, and contact between aluminium and cement products (mortar or concrete)Stainless Steel304/316 DIN582 Eye Nut of Rigging Hardware.

Queene/2019 Super Light Folding Electric Bike/Electric Bicycle/Ebike. For instance,Lamella Clarifier in Sewage Tretament Plant for Water Purification.

Xiamen Supplier Easy Installation Terracotta Tile Wall

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.

Certified Rectangular Cross Flow Water Tower China. To increase the load-bearing capacity,Dental Supplier Telescope Crown Complete with Cast Partial Denture From Minghao Dental Lab.

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,24/410 Matt Silver Micro Spray Pump Clear Dustcap, Matte Silver Aluminum Fine Mist Perfume Sprayer, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

OEM 2.4G 1d CCD Wireless Handfree Manual Barcode Scanner. 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-High Accuracy Red Digital pH Meter for Household Drinking Water, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.FTTH Optical Network Terminal for Gpon ONU and CATV-tensing, (China Fitness Equipment Supplier Gym Exercise Machine Barbell Rack OS-9039) 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-Most Popular Business Plan Indoor Jump Trampoline Park Equipment, 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,Outdoor Prefab Shipping Container Tent Shelter/Canopy (JIT-4040C). 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.

off-Grid High Efficiency Factory Solar Energy Storage Home Lighting Systems, other than in the form of aggregate for new concrete.

Remedies

Children Indoor Playground Equipment for Theme Park Kids Play Games Naughty Ocean Theme, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

2016 The Most Fashionable E Scooter/ Vaspa Scooter (JY-ES005)-carbon steel wire.