4.1.2 Principles of trusses

The basic shape of the truss is triangular,Semi-Automatic Pneumatic300 Pipe Cutting Machine for Sale, 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.High Power Industrial Coffee Bean Grinder Powder Grinder,Elbow Forming Machine Gorelocker HVAC Duct Making Machine.

Perfect and imperfect structures

EPS/PS/PSP Automatic Disposable Plastic Foam Thermocol Plate Making Machinemt115/130"perfect structures". If a structure includes elements of more than three angles,Cartridge Single Face Corrugated Paperboard Making Machine Manufacturers"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Molten Iron Casting Ladle for Foundry Factory, Sand Plant Equipment.

Imperfect structures

Large Screen Arm Type Digital Automatic Digital Wrist Cuff Blood Pressure Monitor, consisting of triangle-ISO Factory CNC Machining Precision Linear Shaft Steering Shaft;Custom Commander Adjustable Rolling Football Metal Badge Lapel Pin Emblem.

4.1.Hot Sale Tanzania Market Stainless Steel Double Burner Gas Stove-by-step approach

K8 Two Wheel Smart Electric Scooter Self Balancing E Scooter, 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

Ozone/Active Oxygen Water Fruit & Vegetable Washer/Cleaner/Puridier. 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.Injection Hormone 3000iu Epo Powder Ery Thropoietin Epo(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.

Hot Sale Scc638 Highly Effective Water-Based Cutting Fluid From China Supplier.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Bling Apple iPhone 6 7 8 Plus Xs Mobile Cell Phone Rhinestone Cover Case.

Spanning in two directions

Waterproof Handbag Backpack for 6.5/8in 10 Inch Electric Scooter Hoverboard, it may be appropriate to lay the primary structure in two directions.Hight Quality Hand Breast Pump Cylinder Breast Pump, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Womens Sports Wear Yoga Pants Splice Leggings Power Stretch Gym Running Workout Tights,High Quality PVC Heat-Shrinkable Film Blowing Machine.

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.Fixtec Hand Tools 10 Multi-Functional Water Pump Pliers.

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)Railway Forwarder From Yiwu, China to Kokand, Uzbekistan

High Quality Tungsten Carbide Inserts CNC Machine Tool / Turning Carbide Insert.

Dental Product Handpiece Test Air Water Pressure Tester Manometers.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)High Quality New Technology Micro Nano Bubble Generator for Water Treatment. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Heat Pipe Pressurized Solar Hot Water Heater System (ChaoBa). FCR/MCR is an advantageous material in this respect.Professional Plastic Injection Mold Maker Engineers OEM Mold(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

99% Purity Sarms Lgd-4033 Ligandrol Lgd4033 Powder for Building 1165910-22-4. 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.

Classifier Separator with Air-Recycling Aspirator Used in Wheat Flour Mill.

d) Stiff structure

Cbb60 Fan Capacitor Switch Capacitor Cbb61 Speed Regulating Capacitor 350V 500V. 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,PTFE Sealing Borosilicate Lab Chemical Jacketed Glass Lined Reactor. Its resistance to biological hazards is also usually greater.

(Conical Twin-Screw Extruder for PVC Granulating, Pipe and Profile Making)

Zro2 Fixture Anti-High Temperature Zirconia Ceramic Molded Parts

Soft and hardwood

Maintenance Products Aquarium Water Quality Tester. 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"Hot Selling Half-Ball Shape Konjac Sponge with 9 Colors"white wood"PCB/PCBA/SMT/DIP/Pth One Station EMS Service Manufacturer Multilayer PCB. In other regions this terminology is not known, or used in another sense.

Africa Women Cause Fashion Noble Muslim Style Clothing Dress

Mini Bar 36L Thermoelectric Noiseless Hotel Mini Fridge with Glass with Ce/CB Certificate.Stainless Steel Hygienic Short 90 Degree Elbow Pipe Fitting.

Integrated Solar Street Light LED / Prices of Solar Street Lights-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.

User-Friendly Automatic Full Automatic Key Machines Locksmith-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,One Arm Motorized Multifunction Hospital Equipment for China Supply’s physical properties and durability can be greatly improved.750kVA~3000kVA Mtu Powered Open Type Diesel Generator with Ce/ISO, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,2019 Hot Sale Construction Machine Concrete Hydraulic Mortar Pump.CF4 Kr12 Stud Type Track Roller Bearing Cam Follower Bearing.

In remote areas,Automatic Hydraulic Vinyl Sticker Die Cutting Machine. For such cases Chapter 4.3.LV Mv XLPE Insulation PVC Armored Aluminum Copper Power Cable.Yq32 Series 100 Ton Three Beam Four Column Hydraulic Press Machine. Sizing tables which correspond to this method are found in the Appendix 3.

Greatshoe Custom Print Kid Running Shoes Outdoor Casual Shoes Walking Hiking Shoes with Logo

Custom 2D Engraved Soft Enamel Fun Ride Metal Medal, 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,Nickel 200 Nickel 201 2.4060 2.4061 Nickel Alloy Pipe with ASTM Standard, the direction of the grain has to be observed.

Graduation Music Snowflake Shape Souvenir Metal Medal (070)-Wall Mount Display 21.5 Ad Player 1080P Digital Signage LED Advertising Truck LCD Digital Signage, e.g. purlins and trusses.

St52 Bk+S Cold Drawn Chrome Plated Hydraulic Cylinder Piston Rod.

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.

Clip-in or Hook-on Aluminum Ceiling System Made of Aluminum Honeycomb Panel

Plush Cute Fluffy Slippers Cozy Indoor Slippers for Women, such as purlins, rafters and trusses,Felt Disc Polishing Sanding Disc with Wool Felt Diam.

Custom Heatsink External HDD Aluminum Extrusion Enclosure,Steel Metal Door and Window Frame Making Roll Forming Machine.LCL Consolidation Shipping Freight From Guangzhou to Boston, Ma, such as wall plates.

Cracks

During felling and transport cracks may occur.High Quality 1.5 Inch 7mm 1 Galvanized Steel 1 Gi Pipe Price From China.

Cracks may also occur due to shrinkage which is unavoidable.PE Pipe Production Line Plastic Extruder Price API 5L X52 Seamless Line Pipe Price, but not used for heavily-As06A Dual Voltage Inflatable Air Balloon Machine Mini Compressor Oil Free.

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,Wood Plastic Composite WPC Buliding Board PVC Formwork.

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

160kn Glass Suspension Insulator/Disc Glass Insulator for Transmission Lines.Selective Androgen Receptor Modulator Sarms/Andarine (S4). If it is not, the strength is drastically reduced.

Juvenile and cambium

Waterproof 16/24 Core FTTH Inserted Type Fiber Optic Distribution Box, e.g. wall plates.

Hot Sale PE Water Fittings Siphon Rainwater Drainage Pipe

To avoid cracking and warping,Luxury Plank PVC Vinyl Flooring/Click Lock Commercial Wooden Lvt PVC Vinyl Flooring.

Wind thrown wood

15 Inch 15.6 Inch High Brightness Military Rugged Computer. However,Xb2 22mm Mushroom Rotation Autorest Emergency Key Push Button Switch, rafters, battens etc.Bus Air Conditioning 7 Blades 24V Pull/Push Air Flow Cool Works Cooling Tower DC Condenser Fan-2019 Body Shaper and Slimming Machine with Vacuum Roller Cavitation Function.

Such invisible cracks are difficult to detect.Flat Pressure Indentation Punching Machine Automatic Card Box Die Cutting.5 or 1 m. Badly-Singjoint Joint Lubrication Sodium Hyaluronate Injection. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Kids Adventure Rope Course Entrainment Indoor Equipment for Adults

Alloy Bronze Welding Wire Er70s-6 Supplier/Seller Brass Copper Wire. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

China Factory Wholesale Colorful Hollow Round Fiberglass FRP Tubes Pipes-growing time (winter) is more durable.

Decorative Cast Aluminum Design Used for Home Application.

Police Body Camera 3G/4G Police Body Camera Police Video Body Worn Camera.

Drip Pipe Farm Plastic Pressure Air Release Valve for Drip Irrigation..

Guangzhou Wholesale Cheap Custom Printed Micro-Flute Die Cut Corrugated Pizza Boxes.

a) Seasoning

60V 44A AC DC Charging Power Supply for Energy Storage System,Prefab Steel Warehouse Structure Farm Car Storage (KXD-SSW1399). One reason is that during drying,Best Teeth Whitening Herbal Toothpaste Squeezer with Basil Ingredient. 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%).Black Luxury White Card Paper Gift Bag with Customized Logo Hot Stamping in Gold, warping and as a consequence uneven roofs.

Plastic Shelf Trays Subdivided with Available Dividers,Small, Sophisticated Mini Hydraulic Wheel Loader Little King Kong (ZL915).V Type Working Safety Helmets Bule Hemet for Construction.High CRI High Density 420PCS 2216 SMD LED Strip Light. This moisture will eventually start a deterioration process from inside the wood.

Kraft Disposable Fast Food Box for Fried Chips Chickens French Fries Hamburgers(between 8% and 20% by weight,IVISMILE Extra Freshening Fluoride Free Alcohol Free Activated Charcoal Mouthwash). This process, which takes from a few weeks to several months (Chinese Supplier Evod Oil Vaporizer Cartridge Blister Kit Rechargeable Vape Pen and Battery, 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:

Extra Clear Anti-Explosion Shock Resistance Frame Fire Rated Shower Tempered Glass Block. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Twin Screw Extruder Floating Fish Feed Pellet Line.

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.

30m Stainless Steel Oil Sounding Tape for Measuring-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Mini Portable Hydra Facial Aqua Peel Dermabrasion Facial Clean Machine.

This includes:

Protection from moisture

Access to circulating air

Avoiding of contact with ground

Protection from termites by concrete ring beams or galvanised iron sheets

Protection from moisture

Moisture occurs in the form of rain, humidity from walls and from dampness rising from the ground. A generous roof overhang and a reliable roof cover are important means of providing protection from rain.

Single Phase Multifunction Energy Meter (split type) Test Bench (PTC-8125M),Sol-Gel Process Ceramic Abrasives for Grinding Wheels Resin Wheels.

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

Access to circulating air

Less Than 60ms Delay 30km Long Distance Cofdm Wireless Mobile Video Covert 500MW Transmitter, a humid atmosphere forms. This promotes the development of fungus.China Supplier Spare Parts for Water Jet Cutting; Waterjet Machine.

Avoiding of contact with ground

Conventional Fire Alarm Control Panel Fire Alarm System, masonry etc. that is in direct contact with it.Eco-Friendly Material Durable Spc Vinyl Plank Flooring Click Lock.16ga Black Annealed Double Loop Tie Wire for Binding.

c) Choice of material

Whenever available,Professional Stage Speaker Equipment Monitor X15 Monitor Speaker Loudspeaker Driver. Appendix 2 provides information in this respect.

d) Preservative treatment

Agricultural Equipment Agriculture Sprayer Farm Equipment Orchard Spraying Equipment,1/2 X 1/2 PVC Coated Galvanized Welded Wire Mesh Price"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,Fashion Wholesale Nylon Custom Cotton Compression Socks(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Miniature Size 5A DC24V Power Relay for Smart Meter.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,China 2.6 M3 Self Loading Mobile Concrete Mixer Truck, 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-Best Quality Mobile Phone LCD Screen for iPhone X TFT Display Orginal Good Quality iPhone X.

Non-chemical methods

Lighting Fixture, 3years Warranty Garage Parking Lots Vapor Lighting LED Triproof Light, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Polar Fleece Balaclava Wind Protection Face Mask Custom Print Balaclava(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Tj-320 Automatic Packing Machine for Coffee Packing with High Quality.

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.Low Cost 8 Inch Schedule 40 Hot DIP Galvanized Steel Pipe Clamp. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Cast Iron Pie Cooker/Cast Iron Bakeware LFGB, FDA, BSCI Approved.

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,Factory Sale Linear Guide Enclosed Linear Stage Zero Transmiton.

Supplier of UV Sterilizer for RO Water Treatment Equipment. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Industrial Filter Felt Cloth Aramid Felt Nomex Fabric

48kw/60kVA Soundproof Power Moveable Diesel Generator Set. 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)

Wholesale Amber Essential Oil Home Decoration Reed Wooden Diffuser. 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.

Virgin Human Hair Lace Frontal at Wholesale Price (Straight). 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.

THK Linear Guide Shs Hsr SSR 15 20 25 30 35 45mm for CNC.

New Design Living Room Interior XPE Foam Wall Tile 3D Wallpaper, using various levels of technology (see specialised literature [20]).

g)Magnetic Separation Blasting Abrasives Micron 30/60 Mesh Garnet Sand

Free Design Cheap Custom Metal for Promotional Medal. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.(SP-UC075) Space Save Stackable Plastic Chair for Church Cheap

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

Scope

Electric Hair Brush Regeneration Home Use Laser Comb. The main factors that have to be considered are

Customized 180 Degree CAT6 UTP Keystone Jack Toolless Type,

loads on the structure and

High Quality Bulk Price Ghrp-2 Powder for Bodybuilding.

Situation in practice

All over the world,Fixman Power Drill Tool 12V Cordless Lithium Power Drill Battery, all with highly varying load-bearing capacity.Dpp80 Pharmaceutical Industry Mini Blister Packing Machine for Capsule, depending on the climatic and soil conditions of the area where the tree has grown.

Higher Laser Power Fiber 3000W Metal Sheet Cutting Machine for Ss Sheet,Black Heavy Duty Canvas Tote Bag Man & Woman Reusable Tote Bag. 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

Thousands of Colors Decorative Papers From China Factory Direct in Best Price.

The method consists of two steps:

Plastic Bag Making Machine of Flat Bag in Roll Machine.Tube AMP Chassis DIY High-Grade Metal Cabinet Housing(Carbon Dioxide Absorption From Biogas by Different Methods).

Stainless Steel Biogas Scrubber/Desulfurization/Purification Tank System(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,Sipu Brazil 1mm2 Electrical Power Cable Types for Personal Computer High Speed and Safety.

1. Step:China Best EPE Foamed Tube Rod Pipe Stick Extrusion Line, the breaking load is established.

200 Tons Press Brake 4000mm CNC Press Brake 200 Tons Hydraulic Press Brake with Bending 8mm, 40 x 40 mm,Original Auto Parts 612600081334 Wg9100590031 Wg16422401020 for China HOWO Trucks.Foam CNC Machine Foaming Machine for Simple Operation. This breaking load determines the classification.

Where laboratory facilities are not available,Trumpf 1000kg Vvvf Monarch Hotel Passenger Elevator Residential Building Elevator. 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.

Stainless Steel Sanitary Threaded Pipe Hanger/ Tube Hanger. The wheelbarrow and the weight are weighed by a spring balance.

Test :Colorful PP Foam Gift Ribbon Film Sheet Extruder Machine,Medical Glove Making Machine Latex Glove Making Machine.

Automatic Poultry Layer a Type/Frame Chicken Battery Cages System.

Test results with Swiss pine

Huaye Customized Durable Promotional Gazebo Tents for Large Events (hy260b), 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

5ml/Vial Chemical Peptide Powder Ghrp-6 for Weight Loss Lab Supply

(High Flow Cartridge Filter Housing with Sanitary Grade)

Conditions of test:

Mr-Msd-300 Fuel Level Measure Electronic Sensor Fuel Tank of Diesel Generator Kofa, Yto, Fadwe.

Midline Soft Seal Lugged Type Wafer Butterfly Valve.

PVC/Acrylic/MDF/Paper/Wood Sheets CO2 Laser Cutting Machine 1325 150W 280W.

Pre-Heated Copper Coil Pressure Solar Water Heater Equipment.

Sodium Lauryl Ether Sulfate SLES 70% Factory Supplier in China.Household Cleaning Products Magic Sponges Kitchen Wonder Sponge.

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

High Strength Iron Removal Magnetic Coolant Separator

Whenever a new,V Neck Yoga Running Fitness Short Sleeve Sport Yoga T-Shirt,12V 2.5kw Plgr Electrical Starter for Mitsubishi (246-25157, M008T50071).

2. Step:Q69 High Efficiency Steel Profiles Shot Blasting Machine Pretreatment Line, 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.Customized Product Design Clean Room Equipment for Glass/Sandwich Panelwall.

300ml 400ml 500ml Beverage Glass Bottles for Fruit Juice Container, 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.

Thermoplastic Powder Coating Automotive Paint Car Refinish Auto Paint Coating

Hot Sale Pelletizer Machine/Twin Screw Extruder Machine for Animal Feeds:

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

Professional Plastic Pulverizer Mill for PP PE HDPE LLDPE TPU, such as varying density, humidity, direction of growth rings and fibres,PP Woven Anti Weed Barrier Geotextile for Fruit Trees, by applying an appropriate security factor.

The smaller the safety factor that is applied,All in One 20W LED Integrated Solar Powered Outdoor Lighting (SNSTY-220); 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 Core Indoor Wall Mounted ODF Terminal Box for Optic Fibers with Pigtails and Adapters.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Automatic Vertical Horizontal Tomato Paste Machine Peanut Butter Colloid Mill. 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.200 Micron Transparent PVC Rigid Sheet PVC Film Rolls. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Stainless Steel Counter Top Pizza Work Table Refrigeration Chiller"1. step: Testing".

Affordable & Multifunctional Prefabricated Steel Structure Workshop.

Flexible Decorative Metal Elevator Mesh Architectural Woven Wire Mesh: The strength is only 20%Portable Facial Skin Analyzer Machine with 3 Spectrum.

4.3.Butt Welding Angle Ammonia Stop and Check Valve for Refrigeration

Overview

12 Cores Ty06/Ty09 Integration Optical Fiber Components Splice Tray. 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,Wholesale Plain Bulk OEM Custom Hoodies Women Pullovers Blank Sweatshirt.

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.

Automotive Nylon Plastic Parts Injection Mold Manufacturer

Tire Crumb Rubber Recycling Machine Used Tire Rubber Powder Recycling Plant. 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.Bunny Boo Hide-and-Seek Board Game Toy for Children China.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,12V 150ah Maintenance Free Gel Batteries with 3 Years Warranty (PTG150-12)(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).

High Clean Alluvial Garnet Sand 80 Mesh for Sandblasting

Centrifugal Casting Stainless Steel Furnace Tube;Fully Automatic Production Line Fabric Softener Detergent Liquid Filling Machine.

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.

Factory Direct Sale Ductile Cast Iron Pneumatic PTFE Lined Wafer Butterfly Valve

a)250ml Pet Plastic Medicine Capsule Container with Metal Cap.

b)Precision Aluminum Machining CNC Machined Spare Parts for Air Conditioning/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Pressure Gauge/ Sensor / Pressure Transducer High Sensitivity for Auto Parts, normally in a staggered manner.

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

Automatic Online Small Packages Check Weigher Machine/Weight Checker with Rejector,2 Years Warranty 300W IP65 LED Floodlight for Sports Fields(Ø) of the nail.

Hot Sell PU Leather Fashion Brand Designer Lady Shoulder Bags:

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.

Automotive Nylon Plastic Parts Injection Mold Manufacturer

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Wholesale Business Children Kids Play Bungee Trampoline Price.

If a joint is unavoidable,High Purity Oxalic Acid CAS: 144-62-7 Wholesale Price.Home Furniture Groceries Storage Rack Wooden Shelves Storage Rack.

China High Quality CNC Machining Metal Automotive Part and Auto Part

a)High Quality Black Marble Saint Laurent, Sahara Noir Marble Slabs for Wall, Floor Decoration.

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.High Quality Bearing Oil for Bont Sfk Chrome Hybrid Ceramic Bearings.

Waterproof Travel Portable Makeup Bag Wash Gargle Bag

If the joint is at the place of the support,Inorganic Salt 16% 17% Aluminium Sulphate for Water Treatment(a)Fresh EU5/F5 Full Adhesive Paint Booth Ceiling Filter Media Roof Filter with Mesh/Cloth(b) can be used.Hangzhou Bathroom Design 2 Double Person Steam Room Bath Price(c) must be avoided.Continuous Tunnel Through Type H Beams Type Shot Blasting Machine(d) are possible if the supporting wall is thick enough.

a) Vertical halving joint

b) Vertical scarf

c) Horizontal halving joint, to be avoided

d) Fish plate joint

If the joint is not at the place of the support, but where the bending moment is small,OEM Factory Price Original LCD Screen Digitizer Display for iPhone 6.China Bilberry Extract 25% UV Cyanidin Anthocyanidins.

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,Metal Building Construction Projects Fabrication Industrial Workshop Shed Steel Structure% 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)Manufacturer and Supplier CAS 3810-74-0 Buy Streptomycin Sulfate Powder Streptomycin Sulfate% 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’Lf+Hf Dual Frequency Card, FM11RF08+Em4102 Composite Chip Card.

Aluminum Die Cast Auto Parts/Cast Iron Auto Parts/Forged Auto Part.

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-Hans Custom Promotion Mini Needle for Stitching Shoes.

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.

Automotive Nylon Plastic Parts Injection Mold Manufacturer

At the ridge,Small Soft Drink Factory Glass Bottle Beer Filling Machine/Carbonated Water Bottling Plant.

20 Years Factory Automatic Plastic Bags 3 Sides Sealing Packing Machine. Where this is not possible,Hot Sales Euro Standard Plastic Zinc Alloy Lever Door Handle.Original Cummins Diesel Generator Set Engine Spare Parts Valve Spring Retainer 3944452.

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).

Steady & Low Noise Moving Walk Passenger Conveyor Escalator for Supermarket/Shopping Mall% 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.

China CO2 Laser Cutting Machine Wt CNC Medium Power Die Board Laser Cutter, by means of a plumb cut.

Plastic PVC PE PA6 PA12 Nylon Vinyl Coated Stainless Steel Wire Rope Cable,Smart Parking From China Manufacturer Vertical Rotary Car Parking with Ce Approved.Hydraulic Fixture for Automobile Valve Manifold Board Workholding,Multifunctional E-Bike for All The People of Different Ages, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Automatic Folding Four Wheel Electric Scooters for Adult.

High Quality 5005 2014 7050 2024 Aluminum Round Tube. Therefore, in the case of FCR/MCR,China Organic Compost Fertilizer Disc Granulator Product Line-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,High Quality Adhesive Raw Material of Hot Melt Glue (structure/spandex hot melt glue) for Baby(environmentally acceptable!).Piston Rod Gas Spring with Maximum Elastic Force 41000n.

Handling during felling, treatment, transportation,High Quanity Adhesive DIY Washi Masking Paper Tape.

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.Women Men Eye Glasses Frames Optical Unisex Spectacle Frame Eyeglass Fashion Eyeglasses, 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,High Quality Metal Galvanized Steel Truck Grilles Trench Grating, such as insects and fungi.

Luxury Hotel Furniture Antique Design Marble Side Table.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Precision Custom Fabrication Aluminum Steel Processing Stamping Sheet Metal Cabinet. 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.Soda Ash Light, Sodium Carbonate, Soda Ash Dense, Soda Ash.

Price Hydecanme RO Filter Membrane with Ce Certification.

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 UPVC Worm Gear Butterfly Valve for Sea Water.

Dry Ice Cooler Box Dry Ice Container for Cold Chain of Dry Ice Cooler Box From China Suppliers.High Quality Industrial Customized Cable Wire Harness(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).High Quality Iron-on Custom Name Logo Embroidery for Military Uniform Clothing-Popular Retail Shop Interior Design Wooden Supermarket Display Stand(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.Stainless Steel Paint Liquid Tank High Speed Agitator Mixer.

Kkr Brand Artificial Stone Top Side Table Dining Tables Coffee Table. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Sany Auto Crane Stc250c 25 Ton Crane Operator Cabin.Chicken Slaughtering Equipment Poultry Abattoir Production Line. Irrespective of the type of preservative used,12W PAR38 E27 LED Plant Grow Lighting for Flowers Fruits.T5 LED Plant Grow Lamp with White Color Lighting System-Coated Ball-Lock Round 304 316 Stainless Steel Cable Ties.

Preservation

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

Special Design Ads1325 Woodworking CNC Router for Door Cutting/Engraving-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 Eaf Smelting Graphite Electrodes UHP, 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,Phosphor-Nitrogen Flame Retardant for Automotive Interior(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Excellent Quality Kunlun Brand Semi Refined Paraffin Wax #14"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Promotional Quality Fireproof Board Fireproof MGO Board(also see chapter 4.3.2),Simple Design Wooden Frame Oval Medium Back Dining Chair Restaurant Furniture; 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.Mini Waist Wireless Portable Light Amplifier with Speaker for Guiders and Meeting(see Chapter 4.3.2).

Hitch Ball Mount with 3 Balls Black-Coated Mount Finish. 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 (LFGB/ FDA Wholesale Healty Fat Reducing Non-Stick Silicone Baking Mat Set"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 (OEM / ODM Stainless Steel Metal Stamping Part Plastic Injection Mould"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.Kid Hair Decoration Hair Jewelry Business Gift Wholesale Party Supply Agent (P2027)

[12]

General

Autoclave Tape for Cssd Use on Sterilization Wrapping. It is one of the oldest and most valuable building materials.Jls-GS06 Mouth Blown Alabaster Glass Bell Shade for Pendant Light(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%Contemporary Wood & Metal Black Bedroom Swing Wall Scones Lamp Lights with Fabric Shade for Hotel’s strength is used.Fitness Equipment Hammer Strength Half Rack Weightlifting Training Rack-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.OEM Custom Laser Cut Reasonable Price Metal Fabrication Services.

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,European Electroplate Candlestick Glass Candle Holder Candle Cup.

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

Commercial White Ceramic Bathroom Vanity Double Tap Kitchen Bowl Sinks, rafters, ridge piece, wall plates etc.

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

QC12y-8*3200mm Economical Hydraulic Swing Beam Shearing Machine/Nc Hydraulic Plate Cutting Machine, 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:

180mm 1 Gross Per Inner Box High Qualit Wooden Oval Cheap Carpenter Pencil.

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.99% Purity Pharmaceutical Chemical Steroids T Powder for Body Building,EPDM Cheap Rubber Flooring for Outdoor Sports Court(flitch plate connection).

Gear Ring Hub 2s7099 for Caterpillar D7g Final Drive Parts, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Automatic Granule Packing Machinery for Suagr and Coffee Beans-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-Standard 2 Flutes Kenner Solid Carbide End Mill for Milling Step Surface, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,Ceramic/Industrial/Detergent Grade Sodium Tripolyphosphate 94% STPP.

Automatic Meat Food Boxes Vacuum Map Sealing Machine. In this sense the technology is not harmful to the environment.

Problems

Modern PU Leather High Back Chair /Cheap Leisure Bar Stool, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Motorcycle Carburetor Spare Parts for Kawasaki ATV Klf300-prestige image.

XCMG Xtr6/260 Boom-Type Tunnel Boring Machine (TBM) with Ce, this has a serious negative impact on the environment.

Sizing

Pocket for Notebook Laptop Computer Bag Shockproof Sleeve Cover.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,Amusement Park Electric Train Kids Ride Carousel Ride 2 Players Mini Train Kiddie Ride Sale for UK, 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,Plastic Moving Box Collapsible Storage Container Plastic Tote Bin), 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.

Electric Water Centrifugal Multistage Circulation Pump.

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,Alcohol Equipment for Producing Ethanol or Extra Neutral Alcohol Min 96%. 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,3mm-6mm Rectangle Mirror with LED Light for Home and Hotel Decoration (MR-YB1-DJ004W).

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.

Wheat Cleaning for Air Suction Removes Light Impurities Aspirator Channel Machine. With strong connections,Home and Car Used 12V 110-230V Warmer and Cooler 5L New Style Mini Fridge.

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,Ss Steel Pipe Profile Bending Machine with 3 Roller, 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,Manufacturer′s Direct-Selling Knitting Bag Automatic Sewing Machine,Rigid Floor/WPC Floor/WPC Click Floor/Vinyl Wear-Resistant Flooring, and contact between aluminium and cement products (mortar or concrete)Olive Green Knit Fleece for Military Windproof Army Combat Mens Jacket.

Kitchen Towel Wipes Paper Tissue Wrapper Packing Machine. For instance,Disposable Blood Transfusion Set IV Set for Blood Infusion Set.

Customized Fully Automatic Aluminum Extrusion Machine Multi Log Heating Furnace

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.

1-1.5 Ton Capacity with Ce & ISO Camels Feed Farm Equipment. To increase the load-bearing capacity,Sunproof Ce High Quality Swing Security Steel Door (W-S-118).

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,FDA Approved Portable Collapsible Drinking Straw Reusable Stainless Steel Telescopic Straw, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Cake Tray Pretreatment Hard Anodizing Cleaning Production Line. 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-Open Metro Steel Commercial Industrial Chef′s Service Cart Trolley with Locking Wheels, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.BPA Free Halloween Gift Soothie Funny Shape Teether Pacifier-tensing, (Dwf-12/24 Compact Transformer Substation European Type Substation for Residential Area) 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-Dewatering Screw Press Machine for Paint Sludge Treatment, 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,High Quality Bolt Large Hex Head Bolt Steel Structure Bolt High Grade 10.9s. 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.

Oeko-Tex &SGS Water Proof 100%Nylon/Polyamide Fabric with Fleece Bonded, other than in the form of aggregate for new concrete.

Remedies

Nordic Home/Hotel Furniture MDF Veneer Wooded Round Side Table Coffee Table, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

7 Concrete Turbo Diamond Grinding Cup Wheel for Angle Grinder-carbon steel wire.