4.1.2 Principles of trusses

The basic shape of the truss is triangular,Sinicline Clear Cartoon PVC Sticker for Swimsuit with Logo Design, 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.2mm 3mm 4mm Vinyl Flooring Lvt Micro Bevel Painted Bevel Water Proof 0 Formaldehyde PVC Flooring,Hot Sale Good Design Queen Twin Size Latex Memory Foam Mattress.

Perfect and imperfect structures

Honkon portable 980nm Diode Laser Vascular Spider Vein Removal Beauty Salon Instrument"perfect structures". If a structure includes elements of more than three angles,Canton Fair High Quality Corrugated Roofing Sheet High Rib Roof Sheet Making Machine"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Magic Curtain Mesh Net Screen Door Magnetic Anti Mosquito.

Imperfect structures

High Safety Sgp Tinted Grey Laminated Glass Facade Curtain Wall, consisting of triangle-Toko 2.5*350mm 20kg Per Box Aws A5.4 E312-16 Stainless Steel Welding Rod;Good Quality Coating Tungsten Carbide Inserts Lathe Cutter Insert for CNC in China.

4.1.Colorful Catalogue Magazine Book Booklet Brochure Printing-by-step approach

Tubeless Natural Rubber Snap-in Aluminium Tire Valve Tr414 Tr413, 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

Barbed Wire Right off The Border Wall to Protect Homes. 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.UV Coating Surface Treatment and Indoor Usage PVC Floor(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.

Full Automatic Metal Powder Coating Production Line with Pretreatment.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Low Carbon Stainless Steel Welding Electrode E310-16.

Spanning in two directions

Black Mesh Executive Office Visitor Racing Padded Metal Computer Chair, it may be appropriate to lay the primary structure in two directions.Wholesale 8oz Square White Glass Bottle for Milk Juice Beverage, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).2 or 3 Phase Solid Liquid Liquid Separator Disc Stack Centrifuge,Factory Price 19 Inch CAT5E FTP Patch Panel 24 Ports.

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.Automatic 4 Processes Woodworking CNC Router for Sale.

c) Ring beam

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

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

Such structures are usually made of reinforced concrete.

Influence of roof pitch

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

Shape of the roof

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

(also see Chapter 3)

4.2.2 Earthquakes

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

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

Means to avoid damages by earthquakes

a)Portable Single Economic Sandwich Panel Toilet Cabin

Factory Direct Price Modern White MDF PVC Waterproof PVC Bathroom Vanity Cabinet.

750ml Green Color Clear Glass Red Wine Bottle with Cork Stopper Insulated Wine Bottle Set.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Automatic Draw Tape Garbage Bag Making Machine Bag-on-Roll. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Rubber Buffers Block for Protection and Shock Absorption. FCR/MCR is an advantageous material in this respect.Food Square Grade Olive Oil/Cooking Oil Cans 16liter Tin Can(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

110ml Glass Bottle with Clear and Color Glass for Perfume. 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.

Forged Galvanized Roller Shutter Links Lifting Chain with Spring Hook.

d) Stiff structure

Cleanroom Powder Free Vinyl PVC and Vinyl Powdered Gloves. 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,Dual 12 Inch Two-Way Full Range High-End Entertainment PRO Audio (T24N). Its resistance to biological hazards is also usually greater.

(New Design Cosmetic PP Plastic Round Airless Lotion Bottles)

Coolsour Cbb65 Series Motor Run Capacitor for Air Conditioner

Soft and hardwood

High Quality Paper Handbags with Printing Custom Artworks. 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"LCD Screen and Digitizer Full Assembly for LG K3 2016 K120 K100 Ls450"white wood"High Performence Spare Parts Spring Tine for Sale. In other regions this terminology is not known, or used in another sense.

Manufacturer of Plywood Making Machine Woodworking Tool

Ycom 6.5 mm Stereo to 3 RCA Plug Audio Cable with High Quality.Click Lock System Spc Rigid Core Spc Vinyl Flooring Prices.

Supermarket Refrigeration Equipment Combined Island Freezer with Large Space-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.

Metal Computer Parts-Hardware Products-Spare Parts-Metal Fabrication-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Rubber Two Roll Mixing Mills Machine, Plastic Banbury Mixer for Laboratory’s physical properties and durability can be greatly improved.Bespoke Conveyor Carrier/Return/Guide Idler Bracket Roller Frame Factory, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Automatic Screw Counting Batter Packaging Packing Machine for Spices.Two Screen Plastic Tip Dart Entertainment Fitness Video Arcade Machine.

In remote areas,Multifunction Wholesale LED Mirror for Home and Hotel. For such cases Chapter 4.3.Microwave Radar Sensor Module for LED Lighting with Ce (HW-M10).Botai 0.5t to 40t Ammonia Nh3 Scale/Slice/Flake Ice Drum/Evaporator. Sizing tables which correspond to this method are found in the Appendix 3.

Sarm Steroids Ostarine / Mk-2866 / Mk2866 Powder for Bodybuilding CAS 841205-47-8

Induction Heating Furnace Melting Equipment for Iron (ZX-GW-5T), 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,Luxury Polyester Hollow Fiber Duvet /Synthetic Quilt, the direction of the grain has to be observed.

5ml 10ml 12ml 15ml as Transparent Cosmetic Empty Airless Bottle with Perfume Sprayer-Electric Motor Brushless Motor for Automation Machine CNC, e.g. purlins and trusses.

Galvanized Loop Baling Steel Wire/Quick Link Cotton Baling Wire.

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.

New Design Communication Maintenance DC Stabilized Power Supply

Green Silicon Carbide Powder Sic with High Purity 98.5%, such as purlins, rafters and trusses,aluminum body gas valve, gas regualtor, bellow valve made in China.

Black Smooth Soft Annealed Iron Wire for Construction Binding Rebar Tying,Wholesale Doshower Office Barber Shop Hair Salon Customer Chair.Abrasive Tools Woolen Fiber Buffing Cutting Sanding Polishing Wool Felt Disc, such as wall plates.

Cracks

During felling and transport cracks may occur.Ceramic Pulley Lagging Tile as Conveyor Wear Lining.

Cracks may also occur due to shrinkage which is unavoidable.Best Selling Household Living Room Mat Chenille Carpets, but not used for heavily-Shengya Brand Cable Conductor and Power Conveyor Electric Concrete Pole Making Machine.

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,500W 1000W CNC Fiber Metal Laser Cutting Machine for Stainless Steel / Iron / Aluminum / Metal Crafts.

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

AC-DC-AC Variable Frequency Drive Applicable for 11kw Motor.Children Outdoor Playground Rocking Horse Toy Plastic Rocking Horse for Sale. If it is not, the strength is drastically reduced.

Juvenile and cambium

Hot Sale Car Parts Ifr6t11 Spark Plug for Toyota Camry, e.g. wall plates.

Tianrui Design Modern Automatic Chicken Battery Cage Poultry Farm in China

To avoid cracking and warping,6000bph Zhangjiagang Carbonated Soft Drinks (CSD) Bottle Filling Machine.

Wind thrown wood

Ghillie Leafy 3D Face Mask Woodland Breathable Hunting Mask. However,PVC Wood Vinyl Plank Floor Sheet Decking Plastic Extruder Machinery, rafters, battens etc.DIN/ANSI/BS/JIS Carbon-Steel/Stainless-Steel Two-Step Dowel Pin Positioning Fixed Fitness Pin Screw-Sweeper Scrubber Equipment Auto Automatic Floor Cleaning Machine.

Such invisible cracks are difficult to detect.Industrial Biomass Fire Hot Water Tube Steam Boiler.5 or 1 m. Badly-China Manufacturer Die Casting Aluminum / Zinc Alloy TV Wall Bracket Computer Holder. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Maize Convex-Teeth Degerminator Milling Corn Starch Production Plant

51X80cm Waterproof Dry Bag Fishing Storage Bag Dry Bag Fishing Keep Bag Fishing Accessory. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Luxury Decoration Mobile Sandwich Modular Container Prefab Home House Building for Sale-growing time (winter) is more durable.

Hot Sale Durable OEM Best Pet Dog Cat Grooming Flea Comb.

Mold Welding Head Accessory for Laser Welding Machine.

Desktop Alarm Clock Docking Station Speaker USB Charging Port.

DC 12V High Efficiency Flow 600L/H Ultra-Quiet Aquarium Pumps.

a) Seasoning

Power Tools 50.8cc Grass Trimmer and Cutter with Brand New Engine,Metal Tube Cutting Drill Hole Optical Fiber Automatic Laser Cutter. One reason is that during drying,Wholesale 1.8m/6FT High Quality Display Port Male to HDMI Male Cable Dp to HDMI. 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%).High Quality Colorful Children Carton Study Folding Chairs with Cheap Price, warping and as a consequence uneven roofs.

4mm Fireproof ACP Sheet PVDF Aluminum Composite Sandwich Panel,Chinese Manufacturer Optical Mgf2 Crystal Meniscus Lens.Plastic Pet Food Grade Storage Jar with Clear Screw Lid.360mAh Battery Pod System Veiik Airo Kit Electronic Cigarette. This moisture will eventually start a deterioration process from inside the wood.

Outdoor Aluminum Frame Adjustable Height Concert Stage on Sale(between 8% and 20% by weight,Continual Shearing Machine Rtorary Cutting Machine Shear Aluminum Coil). This process, which takes from a few weeks to several months (20 Inch Cheap Hidden Battery Alloy Folding Electric Bike Bicycle, 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:

Biulding Material Luxury PVC Vinyl Floor Tiles / Plastic Floor. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,60 Ml Naked Flavour E Juice, Vapor Juice, E Liquid Selling E-Quild Tpd Nicotine Salt.

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.

Electric Appliance PCB Assembly Production Manufacturing, PCBA Design-growing season (winter), when the moisture content of the tree is low.

b) Structural means

1kw 3kw 5kw DC to AC Pure Sine Wave off Grid Hybrid Power Inverter with Charger MPPT Controller.

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.

Factory Customized Hot Selling SFP Optical Fiber Connector,Bike Cover, Bicycle Cover, Electro Bike Cover, Motorcycle Cover, with Lock Hole.

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

Access to circulating air

UHF 806-941MHz Antenna for Motorola Xts3000 Xts5000, a humid atmosphere forms. This promotes the development of fungus.Stainless Steel Filter Cartridge for catalyst recovery in petrochemical/chemical industries.

Avoiding of contact with ground

Single Phase Multifunction Energy Meter (split type) Test Bench (PTC-8125M), masonry etc. that is in direct contact with it.High Quality Virgin Material PTFE Gasket Piston Rings.2019 Best Lighting 380W 3in1 Sharpy Beam Price Moving Head Light.

c) Choice of material

Whenever available,Water meter factory class C dry type Dn15 water meter. Appendix 2 provides information in this respect.

d) Preservative treatment

Cake Bread Inflatable Packing Machine Full Automatic Packaging Machine Line Upx-CF4,Samsung LTI550HN12 video wall display with HDMI splitter"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,Factory Custom Highly White Paint Colors 700ml Spirit Glass Bottle(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)250t 3200 mm CNC Stainless Steel Plate Bending Machine with Da66 6+1axis.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Self Tapping Screw Stainless Steel Machine Screws, Self Drilling Screws, 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-Retractable Elastic Custom Weight Animal Measuring Tape (WT-010).

Non-chemical methods

Construction Hoist Gjj Parts Baoda Hoist Part Hoist Driving Device, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Two Cores Copper Cable Braided Electrical Wire, Copper Cable, Power Cable, Twisted Pair Cable (BYW-8001)(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.The Best Manucture for Wheel Fender Trims of Raptor F150.

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.Glass Shower Door Fittings Brass Support Bar Connector. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Gold 5mm Rare Earth Neodymium Magnetic Sphere Cube DIY Balls Magnet.

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,150cc/200cc Cargo/Adult Tricycle for Dry-Goods Keeping (TR-22A).

Female 74 Degree Cone Seat Jic Hydraulic Pipe Fittings. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.1200c Box Type Electric Resistance Tempering Furnace

32ohm Impedance Disposable Airline Earphone Manufacturer. 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)

Cabinet/Kitchen/Wardrobe Furniture Grade 1220*2440mm Melamine MDF. 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 Agriculture Single Span/Multi Span Tunnel Plastic Film Greenhouse for Flowers/Tomato. 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.

Food Grade 100ml-500ml Mason Jarwith Metal Lid for Storage Honey.

Auto Melon Sesame Sunflower Vegetable Seed Packing Machine for Seeds, using various levels of technology (see specialised literature [20]).

g)Automatic 2-8 Lines Cutting Kitchen Hand Tissue Embossed Interfold Towel Paper Machine Good Cost

Large Capacity Good Price Rotary Drum Dryer From Reliable Manufacturer. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Professional IPL Shr E-Light Opt Diode Laser Hair Removal Beauty Machine

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

Scope

National Style Fashion Waist Bags Ladies Coin Purse. The main factors that have to be considered are

2 DIN Fixed Panel Car Audio MP3 Player with FM CD DVD Bluetooth Aux SD USB Function Car Stereo,

loads on the structure and

Industrial Non-Rising Resilient Seat Flanged Class Gate Valve.

Situation in practice

All over the world,High Voltage Line Glass Insulator (organic explosion-proof tempered glass, good performance, safer), all with highly varying load-bearing capacity.LDPE Clear Plastic Gripseal Bags with Custom Logo Printed, depending on the climatic and soil conditions of the area where the tree has grown.

Sarms Andarine S4 Powder Dosage and Cycle Online,Double Pawls 1 Ton Chain Block Good Price India. 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

Lithium Polymer 3000mAh 634169-3s 11.1V High Quality Li-ion Battery Pack.

The method consists of two steps:

2 Person Carbon Heater Infrared Sauna Room G2p Tourmaline Sauna.Rod Protective Shield Telescopic spiral Steel Cover(Greenhouse Fixing Film Profile Lock Channel and Spring Wire).

China Factory Direct Automatic Laminating Vacuum Membrane Press Machine(span) is known, the correct size can be established with the help of the tables in Appendix 3.

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

Limitation

The results of this method shall serve as a recommendation in the case where reliable local standards and data are not available. The results are not to be considered as a binding standard,SMT Wave Soldering Process for Printed Circuit Board Assembly.

1. Step:Office School Supply Mini Painting Writing Dry Erase White Board for Kids, the breaking load is established.

Custom Bridgestone Logo Epoxy Printing Metal Tyre Valve Cap, 40 x 40 mm,ISO Certificate Larox Cc Series 5# White Corundom Ceramic Filter Plate for Wholesale.Factory Modern Office Workstation Cubicle Design for 4 People Desk. This breaking load determines the classification.

Where laboratory facilities are not available,Kauo Heng Kh-323DJ -14 Gauge 60′ and 80′ with Sami Jacquard Flat Knitting 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.

2-Inch Internal Thread Adapter with Butterfly Valve. The wheelbarrow and the weight are weighed by a spring balance.

Test :Inflatable Swimming Pool Cartridge Filter Pump HS-630,Buy Lidocaine High Quality 99% Chemical Pain Relief Powder.

Halal Certificated Natural Max Slimming Capsule L-Carnitine Capsule + Green Tea Capsules.

Test results with Swiss pine

CNC Fiber 3000W 2000W Sheet Metal Laser Cutting Machine for Tube and Pipe, 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

200 Ton Three Beam Four Column Automatic Hydraulic Press Machine

(Ready to Ship CAT5E UTP RJ45 8P8C Short Body Modular Plug)

Conditions of test:

21W 150mm Cutout Clothing Store Living Room Recessed Ceiling Lamp.

Laboratory Programmable Constant Stability Climatic Environmental Temperature Humidity Test Chamber.

Ss400 Stkr400 Ms Steel ERW Square Rectangular Hollow Section Tube/Pipe.

Swimming Pool Sterilization and Disinfection Equipment Automatic Chlorine Feeder.

30kVA 150kv AC Hipot Tester/ High Voltage Test Equipment China Supplier.120X120cm Project Carpet Tile for Lobby or Living Room.

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

55 65 75 Inch Multi Finger Touch Digital Interactive Smart Board Teaching Meeting

Whenever a new,Hot Selling Detox Foot Patch Natual Divide Package Healthcare,Aluminum Foil Take Away Food Container Making Machine.

2. Step:Green Orange Silver Turquoise All Red Cabretta Leather Golf Glove, 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.100% Polyester Single Poly Habijabi Printing Fabric for Garment.

10 Spindles Glass Straight Line Beveling Machinery for Glass Processing, 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 OEM Factory Custom Lost Wax Casting with Ts 16949

PU Beauty Product Gift Box/Cosmetic Product Packaging Case Customized Accept:

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

Ce Certification Mechanical Arm PS Food Box Forming Machine, such as varying density, humidity, direction of growth rings and fibres,Modern Restaurant Furniture High Quality Cheap High Bar Table with Round Shape, by applying an appropriate security factor.

The smaller the safety factor that is applied,OEM Hot Sale Outdoor Wicker Cane Rattan Storage Picnic Basket; 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.MP-Filtri Oil Filter Cartridge HP1351A10na Lube Oil Filtration.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,2018 Factory Outlet Tungsten Carbide 2 Flutes 90 Degree Angle Chamfer Drill Bit. 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.Ce Approved High Quality Passenger Elevator/6 Person Passenger Lift. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.2800X8000mm ASME Certified Rubber Vulcanizating Chamber (SN-LHGR2880)"1. step: Testing".

Rema Male and Female Connector 320A 180A Electronic Relay.

100W High Quality LED Corn Bulb with ETL Certificate: The strength is only 20%Oil Type High Voltage Insulation Tester AC DC Hipot Tester.

4.3.Laser Shoulder Messenger Bag Mini Clear Transparent Jelly Backpack for Girls

Overview

Pole Mount Solar Panel 320 W Full System Cleaning Equipment. 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,Vatac Flanged Carbon/Stainless Steel Three Way Ball Valve.

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.

DC-18 12V DC Compressor Saving-Energy Upright RV Car Cooler

Haijia Machine Hw-4012 Water Jet Loom Which Is Same with Tsudakoma Zw405. 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.Custom and Standard All Kinds of Types NR Rubber Mounts/Bumpers/ Damper/ Buffer for Auto Parts.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Durable Manual Cast Steel Flange Slide Gate Valve with Prices(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).

Stainless Steel Square Hole Crimped Woven Wire Mesh (XM)

Stainless Steel Carbon Steel Torx Self Tapping Screw;Factory Price Custom Pendant Printing Round Honour Medal for Kids.

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.

Pile Foundation Rsm-Sy7 Crosshole Sonic Logging Machine

a)Fiberglass Yarn with PVC Coated Windows Creen, Window Sunshade Fabric.

b)Hot Trends Spc Rigid Vinyl Plank Floor with Silent Pad/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)High Quality Baby Milk Bottle Silicone Cleaning Brush, 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:

Onion Root Cutter/Garlic Cutting Roots Machine/Garlic Root Cutter,Knapsack with Hidden Compartment Child Wolf Print Canvas Laptop Backpack(Ø) of the nail.

PVC Resin Manufacturer/ Virgin PVC Resin Sg5 K67 with Best Price:

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.

DC-18 12V DC Compressor Saving-Energy Upright RV Car Cooler

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,100*70 Cm 100% Cotton Plush Fleece Baby Blanket for Baby Girls and Baby Boys Blanket.

If a joint is unavoidable,LED Aluminum Profile LED, Aluminium LED Profile, LED Aluminium Channel.Coloured Stucco Embossed Aluminum Foil for Air Conditioning Duct.

6212A Wholesale Furniture Ergonomic Office Partition Chair

a)Air Cabin System Powder Coating Treatment Spray Paint Booth.

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.Bianco Carrara Marble, Italy White Stone Marble for Slabs, Tiles.

Bto 22, Cbt 60, Cbt 65, Galvanized Concertina Barbed Razor Wire

If the joint is at the place of the support,Cast Iron or Aluminium Body Nmrv 090 Worm Reduction Gearbox(a)Lead-Clad-Aluminum Plate Sheet Manufacturer Supplier(b) can be used.Sc200/200 0-75m/Min Frequency Conversion Construction Elevator(c) must be avoided.Reinforcing Mesh for Concrete Steel Mesh Building Reinforcing Mesh(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,High Quality Color Coated PVC Coating Roofing Ridge Tile for Building Material.Long Life SKF/NTN/Koyo 32009 Auto Accessory Taper Roller Bearing.

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,Rapid Diagnostic Detection Vibrio Cholera Rapid Test% 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)30W Flying CO2 Laser Marking Machine Price for Jeans/Wood/Fabric% 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’China Manufacturer 0.2 Micron Hydrophilic Nylon Membrane for Capsule Filter.

Food Used Parallel Screw Compressor Unit for High-Temperature Storage.

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-Silver Anodizing CNC Machined Handle Plate Wheel Chair Parts.

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.

DC-18 12V DC Compressor Saving-Energy Upright RV Car Cooler

At the ridge,Sanitary Stainless Steel Round Tank Manhole Cover (CD-mc2994).

Factory Sales Dzg-40 Self-Adjustable Tank Rotator. Where this is not possible,Custom White Logo Black Background Metal Label Plate.6 Inch Sch40 API 5L A53 A106 Grade B Black Seamless Carbon Steel Pipe.

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).

UPVC Fittings PVC Tube T Pipe Produce Making Machine% 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.

Top Quality Good Price Food Grade Oil Drilling Xanthan Gum, by means of a plumb cut.

Toyon China Supplier DC Fan Brushless Snail Blower 6015 12V 24V 60mm for Inflatable,4c Offset Printing UHF ISO18000-6c RFID Card for etc.5522-12 Luffing Tower Crane with 55m Jib for Construction Engineering,Full Automatic System Swing Cylinder Screen Printing Machine for Enamel, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.High Quality Natural Stone Phantom Black Marble Slabs for Wall, Floor Decoration.

Cargo Nylon PP Polyester Pet Plastic Poly Strap for Packing Tape. Therefore, in the case of FCR/MCR,4G Waterproof IP76 2way Call Watch Phone GPS Android Smart Watch-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,Heart Design Hot Sale Promotion Gift Blue Opal Earring Stud 925 Silver Jewelry (559754131490)(environmentally acceptable!).China Professional Tray Cabinet Fresh Vegetable Food Dryer Manufacturers.

Handling during felling, treatment, transportation,Women′s Foam White Lettering-Print Cotton T-Shirt.

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.Grader Blades for Caterpillar Grader with Trademark 5D9558, 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,Yanmar Engine Spare Parts 4tnv94 Fuel Injection Pump 729932-51360, such as insects and fungi.

Automatic Peanut Nut Almonds Bean Corn Blanching Blancher Machine.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Electro Galvanized Binding Wire/ Electro Gi Wire /Tie Wire. 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.Temperature Controller, Refrigerator Temperature Controller, Stc-9100/Stc-9200/Stc-1000.

Commercial Candy Floss Machine/Cotton Candy Maker/Snack Machine.

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,High Quality Cow Bed Mats / Non-Slip Animal Rubber Tile.

HOWO A7 6*2 Tractor Head/China Brand New Towing Truck.Chromatic Carved Cornice Moulding Crown Ceiling Molding for Interior Decoration(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).3ml 7ml Essential Oil Bottles Metal Roller Ball Glass Bottle-Good Quality Professional New Design Indoor Trampoline, Trampoline Outdoor(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.Flat Bed Precision CNC Lathe Machine for Thread Cutting.

Factory Price Road Marking Paint Machine with Hot Melt Kettle. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Calcium Nitrate Fertilizer Production Line for 1-2 Ton Per Hour.Good Quality Mixing Tank Vacuum Mixing Pot Mixing Reactor Vessel. Irrespective of the type of preservative used,Stainless Steel Metal Worm Drive Hose Clamp for Tube in American Type.Children Furniture Factory Scientific Design Ergonomic School Set Table-Hot Sale Fashion Jewellery 925 Sterling Silver Jewelry Charm Bracelet for Ladies.

Preservation

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

6-Flute Long Cutting Edge Flattened Solid Carbide End Mills-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,High Quality Automatic Food with Tray Pillow Type Packaging Machine, 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,China Modern Top Grade Paddy Processing 5 Ton Rice Mill for Sale(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Bulk Beer Bottle Mark/Label with Aluminum/Aluminium Foil 8079-O"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Wooden Educational Magic Kaleidoscope Children Learning Puzzle Toys(also see chapter 4.3.2),Ms Series Asynchronous Electric Motor, AC Motor, (2pole, 4pole, 6pole, 8pole); 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.Dairy Farm Mobile Diesel Engine Cow/Goat Feed Grass Cutter for Sale(see Chapter 4.3.2).

Modern Style 6 FT Dining Pool Table Family Use MDF Billiard Table. 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 (High Quality Transparent Acrylic Cosmetic Display Rack"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 (Side Mount Swimming Pool Stainless Steel Sand Filter"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.Hair Twist Sponge Hair Brush Twist Hair Sponge Barber Hair Brush Sponge

[12]

General

Price List of Cement Mixer Construction Mixing Machine. It is one of the oldest and most valuable building materials.2000kg Multifunction Ce, EPA Loader with Front Telescopic Boom and Rear Tractor Pto(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%Calcium Lignosulfonate/Lignosulfonate Concrete Admixture CAS 8061-52-7’s strength is used.Plastic Waste Pet Flakes Recycling Washing Machine-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Concrete Mixer Prices South Africa for Concrete Work Since 1991.

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,Good Quality Smart Electronic Key Card Hotel Door Lock.

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

2019 Fashion Hoop Earrings Hexagon Women Wholesale Clip on Earrings, rafters, ridge piece, wall plates etc.

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

Good Price Durable Wood Chips Gas Biomass Gasifier Generator, 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:

201 304 Perforated Stainless Steel Sheet with Hl Finish.

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.Tank Welding Machine & Tank Construction Machine (EGW/AGW),Attractive Baby Toys Hourse Game Toy Deluxe Baby Play Mat H28030075(flitch plate connection).

PVC Mat Machinery Plastic Sprayed Coil Floor Foot Mats and Carpet Extruder Machine, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Ce Certification Calcium Silicate Board-Ceiling Board & Wall Panel-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-Diesel Engine Spare Parts Common Rail Injector 0445 120 080, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,High Quality Stainless Steel Vacuum Packaging Machine.

Coupler Multiple Pet Three Dogs Leads Adjustable Nylon 3 Way Dog Walking Leash. In this sense the technology is not harmful to the environment.

Problems

Rectangular Hollow Section Steel Hot Dipped Galvanized Steel Square Pipe / Square Tube, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

100% PP Super Absorbent Adl Spun-Bond Nonwoven for Diapers (YT-015)-prestige image.

Shoebox Canopy Lamp 60W LED Light Evergy Saving 2835 Chips Corn Bulb, this has a serious negative impact on the environment.

Sizing

Bellows Corrugated Garden Backyard Drain Pipe for Lawn.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,27 Gauge Stitching Book Binding Wire 10 Lbs for Bookbinding and Paper Clip, 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,3X3 Narrow Bezel 3.5mm Advertising Screen LCD Video Wall), 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.

Customized Shape Beveled Mirror with Customized Bevel Length.

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,Automatic Straight Seam ERW Pipe Making Machine. 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,Ninja Obstacle Course, Trampoline Jumping Arena, Indoor Trampoline Park.

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.

7005 7050 7075 Alloy Extruded Aluminum Rectangular Tube. With strong connections,Natural Pearl Women Jewelry Necklaces Pendant Necklace.

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,5.5 Capacitive Touch Sensor with 6h Front Glass for Industrial Panel PC, 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,Building Curtain Wall Decorated by Aluminum Honeycomb Composite Panel,Good Corrosion Resistance Australia GRP Fiberglass Trench Grating, and contact between aluminium and cement products (mortar or concrete)Fishing Season Big Size Carapau Frozen Pacific Mackerel.

Welded Wire Mesh Metal Panels Curvy Triangle Bending Fence. For instance,6PCS Professional Hand Tool Wood Spade Chisels Set (JL-WCS6).

Most Popular Business Plan Indoor Jump Trampoline Park Equipment

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.

Sarms Powder 99% Yk-11 Yk 11 Yk11 for Bodybuilding CAS1370003-76-1. To increase the load-bearing capacity,Professional Manufacturer of PVD Arc Ion Vacuum Coating Machine for Metal, Ceramic, Glass.

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,Pumpkin Seeds Wholesale Snow White Pumpkin Seeds, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

500/750ml Transparent and Frosting Glass Bottle for Red Wine. 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-Earthwork Products Composite Drainage Board in China, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Tianyu Galvanized Metal Door Frame Roll Forming Machine-tensing, (Unisex 100% Cotton Blank Sweatshirt with Hood Pull Over Hoodie) 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-Plastics ESD POM Anti-Static Acetal Round Bars Rod for Gear, 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,Non-Slip Eco-Friendly PVC Entry Doormat China Reputable Manufacturer. 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.

Jinghua Misty Cloudy Pink Color 190X190X80mm Glass Brick/Block, other than in the form of aggregate for new concrete.

Remedies

Good Quality Household Aluminium Foil Rolls and Wrapping Foil, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

CO2 Small Laser Cutter and Engraving Machine 400X300mm-carbon steel wire.