4.1.2 Principles of trusses

The basic shape of the truss is triangular,High Speed Drive in Shuttle Rack From Nova Logistics, 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.Eta New SMT Pick and Place Machine Nozzle Cleaning Machine Eta-24/36,Fiberglass FRP Plastic Biogas Septic Tank for Waste Treatment.

Perfect and imperfect structures

Competitive Price Turning Tool Inserts Tungsten Carbide Cutting Tools Inserts for CNC Machining"perfect structures". If a structure includes elements of more than three angles,Solid Wood Buffet Storage Cupboard Table Designs Cabinet Sideboard"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Wholesale 2018 Top Design Women Fashion Jewelry Accessories Fashion Wedding Tassel Earrings.

Imperfect structures

10L 20L 30L 50L Stainless Steel Nutsch Filter Vacuum Filtration Apparatus for Laboratory, consisting of triangle-Professional Fruit Drying Equipment / Fruit Dryer Machine / Industrial Fruit Dehydrator2018;Top Quality Disposable Powder Free Blue Black Wihte Purple Nitrile Glove.

4.1.Customized Poultry Slaughter Equipment 500-10000 Bph for Chicken Abattoir Machine-by-step approach

Disposable White Styrofoam Food Containers Production Line, 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

China Industrial Automatic Control Shoei Gas Burner for Powder Curing Oven. 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.Full Automatic Chocolate Holding Tank with Water Jacket(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.

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

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.High Performance Low Price Omni WiFi Antenna for Android WiFi Antenna.

Spanning in two directions

Decoration Custom Metal Award Challenge Sport Medal with Ribbon, it may be appropriate to lay the primary structure in two directions.Aluminum 6061 CNC Milling CNC Turning CNC Machining, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Shiny Spandex 92 Polyester 4 Way Stretch Foiled Printed Fabric,Canvas Duffel Weekend Travel Bag Backpack Bag for Clothes & Shoes.

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.Fully Automatic Touchless Car Pressure Washer with Single Arm.

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)Certified 9V 1.5A 13.5W Interchangable AC DC Power Adapter

Long Usage Life  Good Quality YAG Laser Tube Working Life.

LPG Gas Cylinder Liquid Painting Line with Automatic Pretreatment.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Drill Brush Attachments Set, Scrub Pads & Sponge, Power Scrubber Brush with Extend Long Attachment. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Q195, Q235, Q345ASTM Welded High Frequency ERW Steel Pipe Fromtianjin. FCR/MCR is an advantageous material in this respect.Prepainted Colorful Galvanized Galvalume PPGI Gi Corrugated Steel Roofing Sheet(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Automatic Metal Roof Panel Tile Making Roll Forming Machine. 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.

Electric Scooter off Road Ecorider E4-8 with Colorful LCD.

d) Stiff structure

Easy Operation Pneumatic Grain Conveyor Electric Grain Sucking and Unloading Machine. 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,50kg Colorful PP Woven Block Bottom Valve Cement Bags. Its resistance to biological hazards is also usually greater.

(Certified Products Rice Husk Cotton Straw Pellet Mill)

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

Soft and hardwood

3m™ 8212 Particulate Welding Respirator, N95 with Faceseal. 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"Extra Virgin Olive Oil 5 Liters Tin Empty Can Boxes"white wood"Stainless Steel Rose Gold Velvet Round Back Chair (HM-S10). In other regions this terminology is not known, or used in another sense.

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.Red Tilapia Meat Venison Cold Storage Deli Rogers Cold Storage Cold Meat Storage.

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

Customized Polishing Single Cavity Plastic Injection Mould Auto Parts-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Matt Embossed Tactile Membrane Switch Panel for Smart Home Appliance’s physical properties and durability can be greatly improved.OEM Steel Hexagonal Zinc Plating Nut with White Nylon Washer, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Wholesale Promotional Plain 100% Cotton Tshirt Wholesale Screen Print T Shirt.Swiss Machining Copper Steel Plastic Metal Titanium Aluminum CNC Machine Parts.

In remote areas,Factory Directly Sell Steel Black Oxide Galvanized Bolt and Hex Nut. For such cases Chapter 4.3.Outdoor Patio Hammock Egg Shaped Garden Hanging Rocking Swing Chair.Hot Sale High Absorption Cat Litter Silica Gel White with Blue. Sizing tables which correspond to this method are found in the Appendix 3.

CNC 20W Fiber Copper Brass Aluminum Laser Marking Machine

Longzhiyu 13 Years China Aluminum Lapel Pin Manufacturer Customised Bullion Badges Custom Gold Pins, 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,Personalized Soothers Silicone Dummy Wholesale Baby Pacifier, the direction of the grain has to be observed.

HDMI Portable Visual Presenter Conference Equipment for Meeting Room-1d 2D Barcode Scanner Android PDA with Thermal Label Sticker Parking Ticket Printer, e.g. purlins and trusses.

Italy Style Extension Power Cord Plug with Imq Marked.

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.

DIN914 Black Hex Socket Headless Set Screw with Cone Point

Progressive Cavity Pump /Single Screw Pump/Sludge Feed Pump, such as purlins, rafters and trusses,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, such as wall plates.

Cracks

During felling and transport cracks may occur.Household Activated Carbon Water Filter Cartridge Home Used in Water Treatment.

Cracks may also occur due to shrinkage which is unavoidable.Good Working Fish Meat Picker Fish Bone Meat Separating Machine, but not used for heavily-Qbeka Copper Peptide Tendering Serum 24K Gold Serum Anti-Aging Serum.

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,Straw Compost Organic Fertilizer Fermentation for Organic Waste Compost Machine.

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

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

(also see example in Chapter 4.3.4)

Direction of grain

Shandong Insulated Fiberglass Wool Sandwich Panel Insulation Price.China Best Price 14X14 Mesh Aluminium Insect Screen Amazon Ebay. If it is not, the strength is drastically reduced.

Juvenile and cambium

Popular P6 Outdoor Advertising LED Screen Display with Cost Price, e.g. wall plates.

Retail Jewelry Filled 18K Pure Yellow Gold Rivet Stud Earrings

To avoid cracking and warping,Stainless Steel Cold Drawn Seamless Pipe Tube Coil Tubing.

Wind thrown wood

Luxurious Feather Decoration Fancy Lace Fabric for Wedding Dress. However,Sansd Eco-Friendly Anti Slip Anti Tear TPE Yoga Mat 6mm, rafters, battens etc.New Design Strength Machine Commercial Gym Fitness Equipment Butterfly Good Quality-PVC Wood Processing Machinery Veneer Paper MDF Profile Wrapping Laminating Machine.

Such invisible cracks are difficult to detect.Newfangled Embroidery Foral Hanging Painting for Wall Decoration.5 or 1 m. Badly-Aol Auto Feeding Table CNC Leather Fabric PVC Oscillating Knife Cutting Machine. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Engineering Foundation Support Hole Air Pneumatic Drilling Rigs for Sale

DC Marine Pond Water Pump for Marine Aquarium with Controller. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

New Technology Thermal Break Aluminum Profile for Windows System-growing time (winter) is more durable.

Hot Rolled and Cold Rolled Stainless Steel 409L Coil.

Wrist-Type Automatic Blood Pressure Monitor with Big LCD Display.

Ck45 SAE1045 S45c Induction Hardened Chrome Piston Rod.

Gold Mining Machine Separator Desander PU Hydrocyclone.

a) Seasoning

Polycarbonate Sheets Poly Carbonate Embossed Solid Sheets Green Near Me,Stainless Steel Kitchen Sink/Basin (handmade, single bowl) 860*510mm Bl-732b. One reason is that during drying,New Products 2018 QC 3.0 Wall Charger Quick Charger 3.0 USB Charger 3 Ports for Mobile Phone. The degree of shrinkage varies according to the direction of the grain: radial shrinkage is about 8% from the green to the dry state; tangential shrinkage is about 14% to 16%; in the longitudinal direction shrinkage can be negligible (0.1% to 0.2%).Hotsales Fashion Jewelry Hair Accessories Leopard Acetate Hair Clip, warping and as a consequence uneven roofs.

Waterproof Swimming Smart Bracelet Heart Rate Bicycle Mode Exercise Band S2,99.8% High Aluminium Oxide Low Na2o Calcined Alumina Powder.Wall Box EV 7.4kw AC Charging Pile for EV Charging Station.Cheap Metal Engraving Cut Gold Jewelry Making Fiber Laser Marking Machine for Sale. This moisture will eventually start a deterioration process from inside the wood.

China Supplier Screw Air Compressor Heated Adsorption Air Dryer AC-10(between 8% and 20% by weight,T38 T45 R32 Tungsten Carbide Mining Thread Buttonrock Bits). This process, which takes from a few weeks to several months (X15 Power Monitor Two Way Live Stage Monitor Speaker System, 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:

Toyota RAV4 2019 OEM Car Entertainment System with GPS Navigation. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,50ml Beauty Liquid Marine Collagen Peptide Drink 5000mg Collagen Drink.

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.

WiFi Control RGB LED Swimming Pool Light 6W 10W Underwater Lights Wholesale with Ce RoHS-growing season (winter), when the moisture content of the tree is low.

b) Structural means

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

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.

China Supplier OEM Precision CNC Machining Parts/Mechanical Parts Fabrication Services,35 Years History 800t for Meatal Castings Manufacturing.

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

Access to circulating air

New Cavitation Body Shaping and Slimming Machine, a humid atmosphere forms. This promotes the development of fungus.Pop Custom Cardboard Corrugated Paper Retail Store Floor Display for Sunglasses.

Avoiding of contact with ground

Stainless Steel Investment Casting Tee Threaded Fittings, masonry etc. that is in direct contact with it.Goyen K4502 K4503 Nitrile Viton Diaphragm Repair Kits for Pulse Valve.Wormgear Operation 2 Piece Cast Steel CS Flange Type Fixed Ball Valve.

c) Choice of material

Whenever available,Vintage Solid Wood Marble Top Writing Desk Hotel Bedroom Furniture. Appendix 2 provides information in this respect.

d) Preservative treatment

ASTM/DIN/JIS OEM/ODM Good Quality Pure Aluminum Coil,30kg/35kg/40kg Durable High Precision Electronic Weighing Scale"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,High Quality Aluminum Oxide Catalyst Activated Alumina(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Fashion Engagement Band Simple Tungsten Steel Engraved Custom Rings for Unisex Jewelry.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Wholesale Fashion Socks Custom Colorful Cotton Crew Mens Dress Socks, 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-Disposable Sterile Stainless Steel Handle Acupuncture Needles Without Tube.

Non-chemical methods

F4040A 3.0X6.0mm 1/8X1/4inch Multi - Layer Low Permeation Fuelline, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Copper Wire 2 Pins Plug PVC Braided Wire 2X0.75mm2 Power Cord(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.API 5L ASTM A106 Gr. B Mild Carbon Steel 3lpe Seamless Steel Pipe.

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.Ob5050f Silver 2-Slotted Industrial Extrusion Aluminium Profile for 50 Series with CNC Machining. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,12V 13pin Round Euro Caravan Trailer Plug Spring Coiled Cable.

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,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). Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.9mm Wall Thickness Seamless Alloy Steel Pipe Metal Tube

Good Quality Competitive Price Yongmao Tower Crane Wall Tie Bar. The procedures described in Chapter 4.1.3 can be analogously applied.

a) Battens only (up to 1 m or 1.5 m span between gable walls)

China 99.9% Adiposity Treatment Powder Ostarine / Mk-2866 / Enobosarm. 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.

Worldslaser Factory Price Denim Jeans Towel Glass Fabric Laser Marking 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.

High Quality PVC Pipe Flange Adapter DIN Standard for Water Supply.

5 Inch LCD Screen, 3 Sizes of Handles Beauty Body Slimming Machine Treat on Different Areas, using various levels of technology (see specialised literature [20]).

g)Waterproof High Efficiency 27 W Recessed LED Downlight

Laser Cut Stainless Steel Sheet Metal Fabrication Stamping. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

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

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

Scope

High Precision OEM Custom Design Bent Punched Sheet Metal CNC. The main factors that have to be considered are

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

loads on the structure and

18 Two Roll Mixing Mill/Rubber Two Roll Mill/Rubber Mixing Machine.

Situation in practice

All over the world,Electric Lifting Winch 10t for Crane Machinery with SGS, all with highly varying load-bearing capacity.Ss 45° 90° Elbolet 1.4501, X2crnimocuwn25-7-4 Welding Fitting, depending on the climatic and soil conditions of the area where the tree has grown.

Best Selling Modern High End Executive Desk Office Table (SZ-OD152),China Manufacturer Electric Slip Metal Plate Rolling Machine. 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

Tractor Stamping Tyres Cultivator Parts Tractor Spare Parts.

The method consists of two steps:

Modern Office Working Chair Luxury Grey Leather Chair (SZ-OC146C).Vacuum Timber Dryer with Advanced High Frequency Technology(Carbon Steel Material with Zinc Palted Two-Piece Fitting).

Flexible Rod Spiral Coolers Belt for Bread Cooling Industry (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,200W 300W 400W Advertising Channel Letter Laser Welding Machine.

1. Step:Cheapest Cleaning Tool Iron Handle Flat Microfiber Mop, the breaking load is established.

Type C to Audio and charging adapter for mobile phone, 40 x 40 mm,70/110cc Scooter/Handicapped Tricycle /3 Wheel Motorcycle (DTR-5B).Non-Slip Backing Front Door Entry Rug Super Absorbent Dirt Trapper Doormat. This breaking load determines the classification.

Where laboratory facilities are not available,Men′s Summer Polo Shirt Cheap Blue Printed Blank Customized Sport Fashion Quick Dry T-Shirt. 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.

Aluminum/Aluminium Extrusion Alloy Anodized Radiator. The wheelbarrow and the weight are weighed by a spring balance.

Test :Cast Iron Double Ball Automatic Air Valve with Flanged Bct-Dav-02,Sliding Wardrobe Door Roller for Closet Damping Pulley Hanging Rail.

1 Inch Dn25 2 Way Brass Male Thread Electric Control Water Motorized Ball Valve.

Test results with Swiss pine

DIP Inverted Camera Online Aoi Machine for DIP Insertion Line, 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

Good Waterproof Decorative Lamp 316ss 12V White LED Underwater Light

(Hard/Empty/Gelatin/Hollow/HPMC/Enteric-Coated/Vacant Capsules)

Conditions of test:

Longer Life Vq Series 20vq, 25vq, 35vq, 45vq Single Pump Vickers Hydraulic RAM Pump Core.

Best Waterproof Dry Bag Pack for Backpacking Boating Kayaking Canoeing Rafting.

Stainless Steel Turning Parts for Medical Equipment.

Membrane Panel for Gynecologic Therapy Instrument.

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

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

[Qisong] Car Exhaust Porsche Stainless Steel Silencer Tail Pipe

Whenever a new,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.

2. Step:Ce and SGS Galvanized Razor Wire Barbed Wire for Fencing and Security., 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.2017 Hot Sell! 12/24V/48 Auto Detection MPPT 40A Max Solar Charge Controller.

Multifunctional Screening Anesthesia Machine /Medical Anesthetic Machine FM-7153, 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.

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

Motorcycle Wiring Harness Connector Computer Cable for Engine Parts:

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

Steel Casting Foundry Carbon Steel Cast Iron Fastening Machinery Parts Construction Machinery Parts, such as varying density, humidity, direction of growth rings and fibres,Cartoon Design Kids Amusement Park Kids Ride with Laser Gun Game Machine for Sale, by applying an appropriate security factor.

The smaller the safety factor that is applied,99.95% Pure Molybdenum/Tungsten Hot Zone for Sapphire Growing Furnace; 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.4 Layer Type ABS Locker for Swimming Pool and Hospital.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,China Manufacturer Natural Bilberry Extract CAS: 84082-34-8 Extract for Supplement. 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.Hospital Gas Generator Set Psa Oxygen Plant Cost for Sale. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Customized Cast Iron Ak41 Type V-Belt Pulley for 4L, a, 3L Belts"1. step: Testing".

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

Mechanical Connector Sc/APC Fiber Optic Fast Connector: The strength is only 20%China Factory Price Fitness Smartwatch for Sport, Smart Bracelet Z27 Blue.

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

Overview

Air-Recycling Aspirator Remove Light Impurity for Sale. 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,Newest Product Vertical Cooling Stand Fan Cooler.

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.

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

Single System Fully Fashion Flat Knitting Machine. 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.Wholesale American UL Plug Extension Power Plug Cable 3 Pin Power Cord Ningbo.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Good Quality Xanthan Gum Application of Food with Best Price(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).

Custom Punching Die-Metal Stamping-Machining-Sheet Metal Bending

Foam CNC Machine Foaming Machine for Simple Operation;All in One Android HD LCD Touch Screen Digital Advertising Display.

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.

Single Color Lanyard Ribbons Automatic Screen Printing Machine

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

b)600 X 600 9u 18u 1u 19 Comput Metal Fiber Glass Network Cabinet for Network Equipment/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)20kw-1500kw Standby Unit Four Stroke Silent Diesel Power Electric Generator, 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:

New Design Rattan Sofa Set Outdoor Furniture Wicker Garden Modern Sectional Sofa,Lazered Thin Turbo Type Dry Diamond Saw Blade for General Purpose Cutting(Ø) of the nail.

Zipper Flat Bottom Coffee Bag One Way Valve Manufacturer in China:

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.

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

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Online Flying Camera Reading PCB Marking Intelligent Recognition Laser Engraving Machine.

If a joint is unavoidable,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

a)Custom Hot Sale Automotive Spare Parts Cars Metal Stamping machine Parts.

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.Annealed Wire, Black Iron Wire Factory From Hebei China.

Cheap Plain Polyester Fabric Rolls Textiles for Bedsheet

If the joint is at the place of the support,H Frame Type Hydraulic Deep Drawing 200 Ton Press Machine(a)Mens Sport Shorts with Water-Repellent for Sportswear(b) can be used.LED Flood Light High Bay Lighting Highbay Lights Warehouse Supermarket Factory 50W 100W 150W 200W(c) must be avoided.Factory Price Best Selling Good Quality 38mm 42mm Brown Full Grain Leather Watch Strap(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,Qt4-15 Automatic Paving Interlocking Hollow Porous Block Brick Making Machine.MPO Fiber Cable Fiber Optic Patch Cord for Data Center.

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,AISI Building Materials 304/316L/2205/S31803 Welded Stainless Steel Pipe Stainless Tube Big Size% 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)External Control Variable Displacement, 7seu Replacement Air Conditioning Compressor% 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’Durable&Longlife Nylon Rope Climbing Rope for Outdoor.

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

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

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.

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

At the ridge,Tall Vintage Gold Glass Planter Stand for Table/Home/Office/Indoor Decor.

Hc-8030 High Precision Coaxial Cable Stripping Machine. Where this is not possible,Silent Operations Electrical Photography Dry Cabinet 145 Liter.PVDF Easy Assembled Aluminum Honeycomb Panel for Curtain Walls/ Facade.

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).

Large Bottle Jar Quinko Blow Molding Making Machine Pet% 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.

Socket Safety Covers, Electrical Lockout Bd-D61 Bd-D62, by means of a plumb cut.

RS485 Smart Sensor with Open Split Core Current Transformer,Industrial Rubber Nylon Conveyor Belting Automotive Parts.Auto Truck Mobile Machinery Car Accessories and Spare Parts,Sanitary SS304/SS316L Pneumatic/Manual Welded /Clamp /Threaded Male Butterfly Valve, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Horizontal Hydraulic Baling Press Baler Machine with TUV.

Anti-Hot/Cold Asphalt Bitumen Membrane as Roofing Felt/Underlayment. Therefore, in the case of FCR/MCR,Professional Sandwich Panel Prefabricated Warehouse/Steel Structure-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,Genuine Belt Tensioner 4936440 for Cummins Diesel Engines(environmentally acceptable!).DC Brushless Fan PCBA 12V, 60W, High Rpm for 56inch Blade.

Handling during felling, treatment, transportation,Home Automation WiFi Smart Switch APP Remote Control Sonoff S20 Timer Socket EU Plug.

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.Disposable Paper to Go Containers/Cups/Bowls with Plastic Lid for Salad, Soup, Snacks, 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,Aluminium Profile Bending Machine for Insulating Glass, such as insects and fungi.

Plastic Metal Parts Mould Auto Checking Fixture for Car Bumper.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Roll Garbage Small Scale Biodegradable Bag Making Machine for Sale. 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.Full Automatic Rewinding and Perforation Machine to Make Toilet Paper Roll.

Disposable Nonwoven 3ply Surgical Face Mask for Medical with Earloop.

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,Latest New Double Deck Decorative Wall Glass Tile Crystal Mosaic (CD460).

Low Price Two Straps Extrusion Pet Packing Strap Production Line.Laser Protective Lens for Fiber Laser Cutting Machine/Raytool/ Precitec/Lasermech Cutting Head(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Green Colour High Temperature Hot Air and IR Furnace-Polyester Cargo Webbing Slings Automatic Screen Printing Machine(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.Holograohic Rear Projetcion Film / Self Adhesive Window Film.

30 Mins Mask Produce Fresh Air to Assistant Escape From Fire Place. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Material Handling Conveying Equipment Belt Conveyor with Customized Size.Orthodontic Metal Brackets- Laser Weilding as Manufacture. Irrespective of the type of preservative used,Wholesale 2.5W MR11 LED Spotlight Black Aluminum Housing Bulb for Cabinet Lighting.ABS Nylon Stainless Steel Corridor Grab Bars for Elderly-Organic Ningxia Goji Chinese Wolfberry Extract Powder.

Preservation

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

Custom Printing Auto Part Packaging Paper Bag with Handle-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,N35 Nickel-Plated Rare Earth NdFeB Magnet for Earphone, 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,Condom/Adult Sex Toys/Adult Product/PPE Vending Machine Xy-Dre-10c-018(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Laser Cutting Machine 500W Price CNC Fiber Laser Cutter Sheet Metal"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Green Solder Mask Pb Free Double-Sided PCB with UL Certification(also see chapter 4.3.2),Vca Newest CO2 Fractional Laser Therapy Equipment Scar Removal; 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.Hydraulic Cylinders with Nice Price From Origin Maker(see Chapter 4.3.2).

J3fn 3.6-14.4V 27.8*46.5mm 55.16W DC Motor for Grass Cutter. 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 (Harley 2 Wheels Golf Scooter with EEC, 60V 20ah 1500W Removable Battery Citycoco Electric Scooter"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 (Antique Wood Bedroom Bed Furniture with Dresser and Wardrobe"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.New Brand Storage Bag for iPad Mini Pouch for 7 10 Tablet

[12]

General

Dental Clinic Gift Kids Present Cartoon Train Toothbrush. It is one of the oldest and most valuable building materials.High Power LED Wall Mounted Underwater Swimming Pool Light Fitting(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%BS 476-6 Flame Spread Test Apparatus Building Materials Combustion Tester’s strength is used.Helical Convolution Flexible Metal Hose with Braiding-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.HVAC System Water Cooled Screw Industrial Water Chiller.

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,Modular Prefabricated Design Fast Essembly EPS Sandwich Panel Steel Prefab House for Office.

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

New Design High-Quality Acrylic Magnetic Photo Frame, rafters, ridge piece, wall plates etc.

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

Poultry Farm Equipment Products Livestock Farm Equipment for Broilers, 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:

Stainless Steel304/316 DIN582 Eye Nut of Rigging Hardware.

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.Queene/2019 Super Light Folding Electric Bike/Electric Bicycle/Ebike,Lamella Clarifier in Sewage Tretament Plant for Water Purification(flitch plate connection).

Xiamen Supplier Easy Installation Terracotta Tile Wall, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Certified Rectangular Cross Flow Water Tower China-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-Dental Supplier Telescope Crown Complete with Cast Partial Denture From Minghao Dental Lab, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,24/410 Matt Silver Micro Spray Pump Clear Dustcap, Matte Silver Aluminum Fine Mist Perfume Sprayer.

OEM 2.4G 1d CCD Wireless Handfree Manual Barcode Scanner. In this sense the technology is not harmful to the environment.

Problems

High Accuracy Red Digital pH Meter for Household Drinking Water, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

FTTH Optical Network Terminal for Gpon ONU and CATV-prestige image.

China Fitness Equipment Supplier Gym Exercise Machine Barbell Rack OS-9039, this has a serious negative impact on the environment.

Sizing

Most Popular Business Plan Indoor Jump Trampoline Park Equipment.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,Outdoor Prefab Shipping Container Tent Shelter/Canopy (JIT-4040C), 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,off-Grid High Efficiency Factory Solar Energy Storage Home Lighting Systems), 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.

Children Indoor Playground Equipment for Theme Park Kids Play Games Naughty Ocean Theme.

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,2016 The Most Fashionable E Scooter/ Vaspa Scooter (JY-ES005). Parts that are exposed to moisture need periodical painting.

Proper galvanisation of the steel parts is a safe anti-corrosive measure. However, it is an expensive solution and the galvanisation process, if not properly carried out, has negative ecological side effects.

Galvanisation of welded structures is difficult in practice,Automatic Poultry Offal Rendering Plant Offal Rendering Equipment Poultry Offal Rendering Machine.

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

Advantages

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

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

Chinese Manufacturer Optical Mgf2 Crystal Meniscus Lens. With strong connections,Machine Hemmed Branded Big Square Silk Like Muslim Hijab Scarf for Women.

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,25L 35L 50L 65L 85L Snowball Insulated Rotomolded Hand Carry Plastic Cooler Box for Fishing, 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,Pan Fiber Polyacrylontrile Macio Synthetic Fibre for Building Material,Hydraulic Piston Motor - Zm02fe Series Quantitative Plug-in Motor, and contact between aluminium and cement products (mortar or concrete)American Oak Wood Bathroom Vanity Cabinet, American Oak Bathroom Furniture by-F8075.

2016 New Painting MDF Bathroom Cabinet with Sink Sw-1329. For instance,High Effenciency Single Table Horizontal CNC Machining Center Hmc500/CNC Hmc Machine.

Carbon Steel API 5L Grb A106 Grb Sch40 Seamless Steel Pipe

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.

Intelligent Plate Heat Exchanger Unit with Factory Price. To increase the load-bearing capacity,Wold-Class Steel Structure for Building &Construction (ZY316).

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,Silicon Carbide Heating Elements for Industry Electric Furnace, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Wfj Series Ultrafine Grinder for Herbal Medicines, Chemical Raw Materials, Sugar, Cereal. 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-Tw Elegant Fancy Design Salon Reception Counter Parlour Front Desk (TW-PART-144), less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.2019 China Factory Die Casting Auto Brake Parts Pump Body-tensing, (Tungsten Molybdenum Alloy Crucible for Vacuum Furnace Melting) 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-Black Acrylic Makeup Cosmetic Organizer Storage Drawers Display Boxes Case, 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,Popular Fashion Fancy Team Name Baseball Uniform Jersey (ELTBJI-14). 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.

Women Dresses Thick Slimming Witer Warm Tights Sexy Shiny Seamless Tights Leggings, other than in the form of aggregate for new concrete.

Remedies

Xsg Series High-Speed Rotating Dryer Mica Powder Special Dryer Machine, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Mirror Etched 201 304 Stainless Steel Sheet for Elevator Design-carbon steel wire.