4.1.2 Principles of trusses

The basic shape of the truss is triangular,Copper Aluminium /Aluminium Alloy Conductor Concentric Cable, 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.CAT6 FTP RJ45 8P8C Modular Plug Gold Plated Copper Shield 2 Pieces Kit,Customized Precision Stainless Steel Auto CNC Machinery/Machined /Machining Spare Parts.

Perfect and imperfect structures

Pool Accessories Circulation Pump / Filter / LED Light /Pool Ladder"perfect structures". If a structure includes elements of more than three angles,HCG Pregnancy Rapid Test Trip/Urine Pregnancy Test Strip"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Hydraulic Automatic Aluminum Sheet Gantry Shearing Machine.

Imperfect structures

3 Ton Manual Chain Lever Block with Overload Limiter, consisting of triangle-Swivel 3 in 1 Game Tables with Air Hockey Table / Billiard Table / Soccer Games;High Strength Hot Sales Cross Recessed Head Drilling Screw.

4.1.Two Layers Wheeled Leather Travel Duffel Bag for Men-by-step approach

High Quality Bronze Gold Rose Gold Color Titanium Coated Stainless Steel Decorative Plate, 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

OEM ODM Sound Standard Audio 50 Watt Stereo Amplifier. 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.3 Way Brass Hose Tube Fitting Female and Male Run Tee Joint Pneumatic Brass Fittings(a) or in an inclined position along the rafters (b).

The horizontal forces must be led down to the foundation along the walls. Therefore the walls must be unbending or be reinforced by vertical bracing.

4.1.6 Special forms of primary structure

A single main truss

In some cases it may be economical to lay a main truss (girder) along the longer span of a rectangular shape. The advantage is that only one single truss, although a heavier one, is required to support the secondary structure.

PU/EPS/Rockwool Core Material Color Steel Corrugated Sandwich Panel with Different Thickness.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Kayal Factory Direct Sales LC1-D/Cjx2 65A 3p 220V Electrical AC Motor Control Contactor Manufacturer.

Spanning in two directions

Simple Innovative Products Aluminum Glass Curtain Wall Buy From China Online, it may be appropriate to lay the primary structure in two directions.Ventilation System Activated Carbon Air Filter For Hydroponic Grow Room, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Surgical Use Disposable PVC Medical Tube Reinforced Endotracheal Tube,Promotional Gifts Stainless Steel Mug Cup with Custom Printing.

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.Solid Wood Buffet Storage Cupboard Table Designs Cabinet Sideboard.

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 2018 Top Design Women Fashion Jewelry Accessories Fashion Wedding Tassel Earrings

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

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

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Customized Poultry Slaughter Equipment 500-10000 Bph for Chicken Abattoir Machine. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Disposable White Styrofoam Food Containers Production Line. FCR/MCR is an advantageous material in this respect.High Performance JS Polymer Modified Cement Waterproof Coating for Basements(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

China Industrial Automatic Control Shoei Gas Burner for Powder Curing Oven. 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.

Full Automatic Chocolate Holding Tank with Water Jacket.

d) Stiff structure

Factory Evaporative Water Air Cooler with up/Down/Side Discharge. 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,SKF Bearing, Miniature Ball Bearing for Window Sliding Rollers (626ZZ). Its resistance to biological hazards is also usually greater.

(Wholesale Bakeware Metal Stainless Steel Blade Pasta & Pastry Cutter)

Factory Safety Gas Cylinder Brass Valve with Certificate

Soft and hardwood

Carbon Anti-Static Polyester Antimicrobial Knit Weft Dry Fit Terry Fabric. 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"Fully Automatic Touchless Car Pressure Washer with Single Arm"white wood"Certified 9V 1.5A 13.5W Interchangable AC DC Power Adapter. In other regions this terminology is not known, or used in another sense.

Long Usage Life  Good Quality YAG Laser Tube Working Life

LPG Gas Cylinder Liquid Painting Line with Automatic Pretreatment.Black Diving Torch LED Rechargeable Torch with Good Gift Box.

Drill Brush Attachments Set, Scrub Pads & Sponge, Power Scrubber Brush with Extend Long Attachment-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.

Q195, Q235, Q345ASTM Welded High Frequency ERW Steel Pipe Fromtianjin-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Prepainted Colorful Galvanized Galvalume PPGI Gi Corrugated Steel Roofing Sheet’s physical properties and durability can be greatly improved.Automatic Metal Roof Panel Tile Making Roll Forming Machine, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Electric Scooter off Road Ecorider E4-8 with Colorful LCD.Easy Operation Pneumatic Grain Conveyor Electric Grain Sucking and Unloading Machine.

In remote areas,Stainless 825 Seamless Steel Coil Tubes Manufacturer. For such cases Chapter 4.3.High Quality Factory Cast Iron Butterfly Valves.Supply Carbon Steel Pipe Fitting Equal Tee for Manufacturer. Sizing tables which correspond to this method are found in the Appendix 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, 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,Best Electric Commercial Professional Meat Dehydrator Machine, the direction of the grain has to be observed.

White Self-Adhesive and Nonadhesive Pdlc Switchable/Smart Film-125kHz Tk4100 Security Proximity White Blank RFID ID Key Card, e.g. purlins and trusses.

China Factory Directly Sell EPE Foam Light Stick, EPE Foaming Pipe Extrusion Line.

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.

50kg Colorful PP Woven Block Bottom Valve Cement Bags

Certified Products Rice Husk Cotton Straw Pellet Mill, such as purlins, rafters and trusses,300kg/H Feed Processing Sinking Fish Feed Pellet Making Machine.

3m™ 8212 Particulate Welding Respirator, N95 with Faceseal,Extra Virgin Olive Oil 5 Liters Tin Empty Can Boxes.Stainless Steel Rose Gold Velvet Round Back Chair (HM-S10), such as wall plates.

Cracks

During felling and transport cracks may occur.Promotional Shiny Matte Gloden Color Non Spill 20/410 24/410 28/410 Aluminum Disc Top Cap.

Cracks may also occur due to shrinkage which is unavoidable.Waterproof Polyester Fabric Furniture Covering Building Material Moving Blankets, but not used for heavily-Red Tilapia Meat Venison Cold Storage Deli Rogers Cold Storage Cold Meat Storage.

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,High Strength Polypropylene Woven Geotextile Used for Tunnel and Coalmine Reinforcement.

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

Customized Polishing Single Cavity Plastic Injection Mould Auto Parts.Matt Embossed Tactile Membrane Switch Panel for Smart Home Appliance. If it is not, the strength is drastically reduced.

Juvenile and cambium

OEM Steel Hexagonal Zinc Plating Nut with White Nylon Washer, e.g. wall plates.

Wholesale Promotional Plain 100% Cotton Tshirt Wholesale Screen Print T Shirt

To avoid cracking and warping,Swiss Machining Copper Steel Plastic Metal Titanium Aluminum CNC Machine Parts.

Wind thrown wood

Factory Directly Sell Steel Black Oxide Galvanized Bolt and Hex Nut. However,Outdoor Patio Hammock Egg Shaped Garden Hanging Rocking Swing Chair, rafters, battens etc.Hot Sale High Absorption Cat Litter Silica Gel White with Blue-CNC 20W Fiber Copper Brass Aluminum Laser Marking Machine.

Such invisible cracks are difficult to detect.Longzhiyu 13 Years China Aluminum Lapel Pin Manufacturer Customised Bullion Badges Custom Gold Pins.5 or 1 m. Badly-Personalized Soothers Silicone Dummy Wholesale Baby Pacifier. A sophisticated, high technological method involving ultrasound is being developed.

4.3.HDMI Portable Visual Presenter Conference Equipment for Meeting Room

1d 2D Barcode Scanner Android PDA with Thermal Label Sticker Parking Ticket Printer. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Italy Style Extension Power Cord Plug with Imq Marked-growing time (winter) is more durable.

DIN914 Black Hex Socket Headless Set Screw with Cone Point.

Progressive Cavity Pump /Single Screw Pump/Sludge Feed Pump.

Glazed Mug with Tea Strainer Inspection Service/Quality Control.

Industrial Twin Welding Oxygen Acetylene Hose Assembly in Welding Machine.

a) Seasoning

Cocamidopropyl Betaine Cab 35% Cocoanut Amide Propyl Betaine Capb,Mini Barcode Scanner 1d Laser Bluetooth Barcode Reader. One reason is that during drying,Household Activated Carbon Water Filter Cartridge Home Used in Water Treatment. 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%).Good Working Fish Meat Picker Fish Bone Meat Separating Machine, warping and as a consequence uneven roofs.

Qbeka Copper Peptide Tendering Serum 24K Gold Serum Anti-Aging Serum,Straw Compost Organic Fertilizer Fermentation for Organic Waste Compost Machine.Shandong Insulated Fiberglass Wool Sandwich Panel Insulation Price.China Best Price 14X14 Mesh Aluminium Insect Screen Amazon Ebay. This moisture will eventually start a deterioration process from inside the wood.

Popular P6 Outdoor Advertising LED Screen Display with Cost Price(between 8% and 20% by weight,Retail Jewelry Filled 18K Pure Yellow Gold Rivet Stud Earrings). This process, which takes from a few weeks to several months (Stainless Steel Cold Drawn Seamless Pipe Tube Coil Tubing, 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:

Luxurious Feather Decoration Fancy Lace Fabric for Wedding Dress. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Sansd Eco-Friendly Anti Slip Anti Tear TPE Yoga Mat 6mm.

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.

New Design Strength Machine Commercial Gym Fitness Equipment Butterfly Good Quality-growing season (winter), when the moisture content of the tree is low.

b) Structural means

PVC Wood Processing Machinery Veneer Paper MDF Profile Wrapping Laminating 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.

Newfangled Embroidery Foral Hanging Painting for Wall Decoration,Aol Auto Feeding Table CNC Leather Fabric PVC Oscillating Knife Cutting Machine.

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

Access to circulating air

Engineering Foundation Support Hole Air Pneumatic Drilling Rigs for Sale, a humid atmosphere forms. This promotes the development of fungus.DC Marine Pond Water Pump for Marine Aquarium with Controller.

Avoiding of contact with ground

New Technology Thermal Break Aluminum Profile for Windows System, masonry etc. that is in direct contact with it.Hot Rolled and Cold Rolled Stainless Steel 409L Coil.Wrist-Type Automatic Blood Pressure Monitor with Big LCD Display.

c) Choice of material

Whenever available,Ck45 SAE1045 S45c Induction Hardened Chrome Piston Rod. Appendix 2 provides information in this respect.

d) Preservative treatment

Gold Mining Machine Separator Desander PU Hydrocyclone,Polycarbonate Sheets Poly Carbonate Embossed Solid Sheets Green Near Me"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,Stainless Steel Kitchen Sink/Basin (handmade, single bowl) 860*510mm Bl-732b(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)New Products 2018 QC 3.0 Wall Charger Quick Charger 3.0 USB Charger 3 Ports for Mobile Phone.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Hotsales Fashion Jewelry Hair Accessories Leopard Acetate Hair Clip, 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-Waterproof Swimming Smart Bracelet Heart Rate Bicycle Mode Exercise Band S2.

Non-chemical methods

99.8% High Aluminium Oxide Low Na2o Calcined Alumina Powder, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Wall Box EV 7.4kw AC Charging Pile for EV Charging Station(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Cheap Metal Engraving Cut Gold Jewelry Making Fiber Laser Marking Machine for Sale.

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.China Supplier Screw Air Compressor Heated Adsorption Air Dryer AC-10. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,T38 T45 R32 Tungsten Carbide Mining Thread Buttonrock Bits.

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,X15 Power Monitor Two Way Live Stage Monitor Speaker System.

Toyota RAV4 2019 OEM Car Entertainment System with GPS Navigation. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.50ml Beauty Liquid Marine Collagen Peptide Drink 5000mg Collagen Drink

WiFi Control RGB LED Swimming Pool Light 6W 10W Underwater Lights Wholesale with Ce RoHS. 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)

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

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

35 Years History 800t for Meatal Castings Manufacturing.

New Cavitation Body Shaping and Slimming Machine, using various levels of technology (see specialised literature [20]).

g)Pop Custom Cardboard Corrugated Paper Retail Store Floor Display for Sunglasses

Stainless Steel Investment Casting Tee Threaded Fittings. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Wormgear Operation 2 Piece Cast Steel CS Flange Type Fixed Ball Valve

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

Scope

Vintage Solid Wood Marble Top Writing Desk Hotel Bedroom Furniture. The main factors that have to be considered are

ASTM/DIN/JIS OEM/ODM Good Quality Pure Aluminum Coil,

loads on the structure and

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

Situation in practice

All over the world,High Quality Aluminum Oxide Catalyst Activated Alumina, all with highly varying load-bearing capacity.Fashion Engagement Band Simple Tungsten Steel Engraved Custom Rings for Unisex Jewelry, depending on the climatic and soil conditions of the area where the tree has grown.

Wholesale Fashion Socks Custom Colorful Cotton Crew Mens Dress Socks,Disposable Sterile Stainless Steel Handle Acupuncture Needles Without Tube. 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

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

The method consists of two steps:

Copper Wire 2 Pins Plug PVC Braided Wire 2X0.75mm2 Power Cord.API 5L ASTM A106 Gr. B Mild Carbon Steel 3lpe Seamless Steel Pipe(Ob5050f Silver 2-Slotted Industrial Extrusion Aluminium Profile for 50 Series with CNC Machining).

12V 13pin Round Euro Caravan Trailer Plug Spring Coiled Cable(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,New iPhone Xs Max Leather Case Apple 8p Clamshell Multi-Function Card 7 Case Protection Wallet.

1. Step:Automobile Bearing of Spherical Tapered Thrust Roller Bearing (29244), the breaking load is established.

9mm Wall Thickness Seamless Alloy Steel Pipe Metal Tube, 40 x 40 mm,Good Quality Competitive Price Yongmao Tower Crane Wall Tie Bar.China 99.9% Adiposity Treatment Powder Ostarine / Mk-2866 / Enobosarm. This breaking load determines the classification.

Where laboratory facilities are not available,Worldslaser Factory Price Denim Jeans Towel Glass Fabric Laser Marking Machine. 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.

High Quality PVC Pipe Flange Adapter DIN Standard for Water Supply. The wheelbarrow and the weight are weighed by a spring balance.

Test :5 Inch LCD Screen, 3 Sizes of Handles Beauty Body Slimming Machine Treat on Different Areas,Waterproof High Efficiency 27 W Recessed LED Downlight.

Laser Cut Stainless Steel Sheet Metal Fabrication Stamping.

Test results with Swiss pine

Automatic Wood Wool Making Machine Electric Wood Wool Machine, the relevant breaking load is calculated as follows:

Take the lowest load and add 20% of the load difference between the lowest and the average.

The formula to calculate the relevant load is thus:

P1 + 0.2 \|f (P1+P2+P3+P4+P5+P6,6) - P1

Thus for the above example:

134+0.2 \|f(134+140+148+148+168+180,6) -134 = 138 kg

ODM CNC Machining Aluminum Parts Camera Quick Release Plates CNC Part

(High Precision OEM Custom Design Bent Punched Sheet Metal CNC)

Conditions of test:

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

Ss 45° 90° Elbolet 1.4501, X2crnimocuwn25-7-4 Welding Fitting.

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

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).

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

Vacuum Timber Dryer with Advanced High Frequency Technology

Whenever a new,Carbon Steel Material with Zinc Palted Two-Piece Fitting,Flexible Rod Spiral Coolers Belt for Bread Cooling Industry .

2. Step:200W 300W 400W Advertising Channel Letter Laser Welding Machine, 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.Cheapest Cleaning Tool Iron Handle Flat Microfiber Mop.

Type C to Audio and charging adapter for mobile phone, 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.

70/110cc Scooter/Handicapped Tricycle /3 Wheel Motorcycle (DTR-5B)

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

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

Men′s Summer Polo Shirt Cheap Blue Printed Blank Customized Sport Fashion Quick Dry T-Shirt, such as varying density, humidity, direction of growth rings and fibres,Aluminum/Aluminium Extrusion Alloy Anodized Radiator, by applying an appropriate security factor.

The smaller the safety factor that is applied,Cast Iron Double Ball Automatic Air Valve with Flanged Bct-Dav-02; 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.Sliding Wardrobe Door Roller for Closet Damping Pulley Hanging Rail.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,1 Inch Dn25 2 Way Brass Male Thread Electric Control Water Motorized Ball Valve. 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.DIP Inverted Camera Online Aoi Machine for DIP Insertion Line. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Good Waterproof Decorative Lamp 316ss 12V White LED Underwater Light"1. step: Testing".

Hard/Empty/Gelatin/Hollow/HPMC/Enteric-Coated/Vacant Capsules.

Longer Life Vq Series 20vq, 25vq, 35vq, 45vq Single Pump Vickers Hydraulic RAM Pump Core: The strength is only 20%Baby Placemat Functional One-Piece Silicone Feeding Tray / Bowl.

4.3.Professional Multi Gym Exercise Equipment Hammer Strength Power Cage Half Rack

Overview

Best Waterproof Dry Bag Pack for Backpacking Boating Kayaking Canoeing Rafting. 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,Stainless Steel Turning Parts for Medical Equipment.

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.

Membrane Panel for Gynecologic Therapy Instrument

Customized Size Zipper Closure Sundries Clothes Dustproof Storage Duffel Bag with Handle. 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.Medical Equipment Hospital Bed Head Unit with Factory Price.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,[Qisong] Car Exhaust Porsche Stainless Steel Silencer Tail Pipe(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).

Bidet Rinse Spray Head Hand Bidet Toilet Attachment Shower Sprayer Shattaf

2018 New Product IP66 12V 24V 30W 60W 80W 100W Solar Street Lights with Pole;Ce and SGS Galvanized Razor Wire Barbed Wire for Fencing and Security..

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.

Multifunctional Screening Anesthesia Machine /Medical Anesthetic Machine FM-7153

a)China Factory Hot and Cold Standing Commerical Water Dispenser for Home Office Use.

b)Motorcycle Wiring Harness Connector Computer Cable for Engine Parts/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Steel Casting Foundry Carbon Steel Cast Iron Fastening Machinery Parts Construction Machinery Parts, 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:

Cartoon Design Kids Amusement Park Kids Ride with Laser Gun Game Machine for Sale,99.95% Pure Molybdenum/Tungsten Hot Zone for Sapphire Growing Furnace(Ø) of the nail.

4 Layer Type ABS Locker for Swimming Pool and Hospital:

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.

Membrane Panel for Gynecologic Therapy Instrument

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,China Manufacturer Natural Bilberry Extract CAS: 84082-34-8 Extract for Supplement.

If a joint is unavoidable,Hospital Gas Generator Set Psa Oxygen Plant Cost for Sale.Customized Cast Iron Ak41 Type V-Belt Pulley for 4L, a, 3L Belts.

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

a)Mechanical Connector Sc/APC Fiber Optic Fast Connector.

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

Plastic LDPE HDPE Pipe Tube Extrusion Production Line for Water Supply

If the joint is at the place of the support,Air-Recycling Aspirator Remove Light Impurity for Sale(a)Newest Product Vertical Cooling Stand Fan Cooler(b) can be used.Multilayer-Layer PCB with Imersion Silver (immersion tin) & Kb6165(c) must be avoided.Single System Fully Fashion Flat Knitting Machine(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,Wholesale American UL Plug Extension Power Plug Cable 3 Pin Power Cord Ningbo.Good Quality Xanthan Gum Application of Food with Best Price.

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,Foam CNC Machine Foaming Machine for Simple Operation% 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)All in One Android HD LCD Touch Screen Digital Advertising Display% 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’Flexible Accordion U-Type Bellow Cover for CNC Cutting Machine.

Single Color Lanyard Ribbons Automatic Screen Printing Machine.

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-Electrical/Electric DC Gear Motor for Electric Vehicle/Garage Door/Opener.

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.

Membrane Panel for Gynecologic Therapy Instrument

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

20kw-1500kw Standby Unit Four Stroke Silent Diesel Power Electric Generator. Where this is not possible,New Design Rattan Sofa Set Outdoor Furniture Wicker Garden Modern Sectional Sofa.Lazered Thin Turbo Type Dry Diamond Saw Blade for General Purpose Cutting.

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).

Zipper Flat Bottom Coffee Bag One Way Valve Manufacturer in China% 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.

Online Flying Camera Reading PCB Marking Intelligent Recognition Laser Engraving Machine, by means of a plumb cut.

Bathroom Stainless Steel Golden Silver Framed LED Illuminated Lighted Mirror with Touch,Outdoor High Brightness P8 (P10, P6, P5, P4) LED Display Screen for Advertising Visual Panel.Cheap Price Bag Filter Housing Vessel for Water Treatment,Custom Hot Sale Automotive Spare Parts Cars Metal Stamping machine Parts, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Annealed Wire, Black Iron Wire Factory From Hebei China.

H Frame Type Hydraulic Deep Drawing 200 Ton Press Machine. Therefore, in the case of FCR/MCR,Mens Sport Shorts with Water-Repellent for Sportswear-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,LED Flood Light High Bay Lighting Highbay Lights Warehouse Supermarket Factory 50W 100W 150W 200W(environmentally acceptable!).Factory Price Best Selling Good Quality 38mm 42mm Brown Full Grain Leather Watch Strap.

Handling during felling, treatment, transportation,Qt4-15 Automatic Paving Interlocking Hollow Porous Block Brick Making Machine.

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.MPO Fiber Cable Fiber Optic Patch Cord for Data Center, 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,Silicone Coated Fiberglass High Temperature Resistant Hose Guard, such as insects and fungi.

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

The low compressive strength and impact resistance limit its application in construction. Wrong handling,External Control Variable Displacement, 7seu Replacement Air Conditioning Compressor. 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.Durable&Longlife Nylon Rope Climbing Rope for Outdoor.

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

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,Breast Dermal Filler Liquid Enlarge Buttocks Hyaluronic Acid Injectable Filler.

Tall Vintage Gold Glass Planter Stand for Table/Home/Office/Indoor Decor.Hc-8030 High Precision Coaxial Cable Stripping Machine(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Silent Operations Electrical Photography Dry Cabinet 145 Liter-PVDF Easy Assembled Aluminum Honeycomb Panel for Curtain Walls/ Facade(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.Large Bottle Jar Quinko Blow Molding Making Machine Pet.

Socket Safety Covers, Electrical Lockout Bd-D61 Bd-D62. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

RS485 Smart Sensor with Open Split Core Current Transformer.Industrial Rubber Nylon Conveyor Belting Automotive Parts. Irrespective of the type of preservative used,Auto Truck Mobile Machinery Car Accessories and Spare Parts.Sanitary SS304/SS316L Pneumatic/Manual Welded /Clamp /Threaded Male Butterfly Valve-Horizontal Hydraulic Baling Press Baler Machine with TUV.

Preservation

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

180W-250W Aluminum Frame E-Bicycle with Shimano Derailleur (TDE-002)-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,Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment, 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,Professional Sandwich Panel Prefabricated Warehouse/Steel Structure(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Genuine Belt Tensioner 4936440 for Cummins Diesel Engines"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

DC Brushless Fan PCBA 12V, 60W, High Rpm for 56inch Blade(also see chapter 4.3.2),Home Automation WiFi Smart Switch APP Remote Control Sonoff S20 Timer Socket EU Plug; 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.Disposable Paper to Go Containers/Cups/Bowls with Plastic Lid for Salad, Soup, Snacks(see Chapter 4.3.2).

Aluminium Profile Bending Machine for Insulating Glass. 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 (Plastic Metal Parts Mould Auto Checking Fixture for Car Bumper"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 (Roll Garbage Small Scale Biodegradable Bag Making Machine for Sale"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.Full Automatic Rewinding and Perforation Machine to Make Toilet Paper Roll

[12]

General

Disposable Nonwoven 3ply Surgical Face Mask for Medical with Earloop. It is one of the oldest and most valuable building materials.Latest New Double Deck Decorative Wall Glass Tile Crystal Mosaic (CD460)(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 Price Two Straps Extrusion Pet Packing Strap Production Line’s strength is used.Laser Protective Lens for Fiber Laser Cutting Machine/Raytool/ Precitec/Lasermech Cutting Head-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Green Colour High Temperature Hot Air and IR Furnace.

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,Polyester Cargo Webbing Slings Automatic Screen Printing Machine.

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

Holograohic Rear Projetcion Film / Self Adhesive Window Film, rafters, ridge piece, wall plates etc.

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

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

Material Handling Conveying Equipment Belt Conveyor with Customized Size.

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.Orthodontic Metal Brackets- Laser Weilding as Manufacture,Wholesale 2.5W MR11 LED Spotlight Black Aluminum Housing Bulb for Cabinet Lighting(flitch plate connection).

ABS Nylon Stainless Steel Corridor Grab Bars for Elderly, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Organic Ningxia Goji Chinese Wolfberry Extract Powder-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-Custom Printing Auto Part Packaging Paper Bag with Handle, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,N35 Nickel-Plated Rare Earth NdFeB Magnet for Earphone.

Condom/Adult Sex Toys/Adult Product/PPE Vending Machine Xy-Dre-10c-018. In this sense the technology is not harmful to the environment.

Problems

Laser Cutting Machine 500W Price CNC Fiber Laser Cutter Sheet Metal, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Green Solder Mask Pb Free Double-Sided PCB with UL Certification-prestige image.

Vca Newest CO2 Fractional Laser Therapy Equipment Scar Removal, this has a serious negative impact on the environment.

Sizing

Hydraulic Cylinders with Nice Price From Origin Maker.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,J3fn 3.6-14.4V 27.8*46.5mm 55.16W DC Motor for Grass Cutter, 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,Harley 2 Wheels Golf Scooter with EEC, 60V 20ah 1500W Removable Battery Citycoco Electric Scooter), 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.

Antique Wood Bedroom Bed Furniture with Dresser and Wardrobe.

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,New Brand Storage Bag for iPad Mini Pouch for 7 10 Tablet. 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,Dental Clinic Gift Kids Present Cartoon Train Toothbrush.

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.

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

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,Helical Convolution Flexible Metal Hose with Braiding, 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,HVAC System Water Cooled Screw Industrial Water Chiller,Modular Prefabricated Design Fast Essembly EPS Sandwich Panel Steel Prefab House for Office, and contact between aluminium and cement products (mortar or concrete)New Design High-Quality Acrylic Magnetic Photo Frame.

Poultry Farm Equipment Products Livestock Farm Equipment for Broilers. For instance,Stainless Steel304/316 DIN582 Eye Nut of Rigging Hardware.

Queene/2019 Super Light Folding Electric Bike/Electric Bicycle/Ebike

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.

Lamella Clarifier in Sewage Tretament Plant for Water Purification. To increase the load-bearing capacity,Xiamen Supplier Easy Installation Terracotta Tile Wall.

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,Certified Rectangular Cross Flow Water Tower China, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Dental Supplier Telescope Crown Complete with Cast Partial Denture From Minghao Dental Lab. 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-24/410 Matt Silver Micro Spray Pump Clear Dustcap, Matte Silver Aluminum Fine Mist Perfume Sprayer, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.OEM 2.4G 1d CCD Wireless Handfree Manual Barcode Scanner-tensing, (High Accuracy Red Digital pH Meter for Household Drinking Water) 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-FTTH Optical Network Terminal for Gpon ONU and CATV, 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,China Fitness Equipment Supplier Gym Exercise Machine Barbell Rack OS-9039. 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.

Most Popular Business Plan Indoor Jump Trampoline Park Equipment, other than in the form of aggregate for new concrete.

Remedies

Outdoor Prefab Shipping Container Tent Shelter/Canopy (JIT-4040C), grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

off-Grid High Efficiency Factory Solar Energy Storage Home Lighting Systems-carbon steel wire.