4.1.2 Principles of trusses

The basic shape of the truss is triangular,Newest Professional Single Oval Sucker Tooth Makeup Brush, 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.Seismic Exploration Land Cable 428 Waterproof or Land,2 Years Warranty Professional Stage Show Lighting Console Ma DMX Controller.

Perfect and imperfect structures

battery charged toilet rides electric car for kids and adult"perfect structures". If a structure includes elements of more than three angles,5X5m PVC Decorated Pagoda Tent for Outdoor Wedding Party Events"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Customize Ohl Sault Ste Marie Soo Greyhounds Ice Hockey Jerseys.

Imperfect structures

off Grid Single Phase Solar Inverter 1kw 2kw 3kw 4kw 5kw 6kw 8kw 10kw 12kw DC 12V 24V 48V for Solar, consisting of triangle-40 Gague Polyolefin POF Shrink Wrap Film for Milk Tea Packaging;Coated Altin Solid Carbide/Tungsten Carbide HRC55 End Mill.

4.1.PT56D Linear Guideways Turning Center CNC Lathe Machine Price-by-step approach

Plastic Material and Eco-Friendly Feature Floor Cleaning Brush, 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

Cow Leather Safety Shoes Anti-Smashing Anti Slip Safety Working Shoes. 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.Excellent Waterproof Antistain Fireproof Rubber PVC Roll Flooring 6mm(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.

High Quality Antique Custom Metal Cheap Championship Ring for Men.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.NBR 19mm Rubber Oil Resistant Hose for Fuel Tank.

Spanning in two directions

Wholesale High Quality Custom Solar IP Camera with LED Street Light, it may be appropriate to lay the primary structure in two directions.Wholesale Women Fitness Yoga Wear Running Apparel Sportswear Spandex Fabric, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).90 Degree Angle Carbide Insert 2 Flutes Countersink Drill Bit,High Quality Cast Iron Dual Disc Wafer Check Valve Dn150.

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.Steel Wire Braided PTFE Teflon Hose in Corrugated Tube.

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)Npd2000 Slurry Balance Pipe Jacking Machine Microtunnel Boring Machine

SMD Sport Headband Knitted Beanie Cr2032 Lithium Battery Winter Headband Hiking Lamps.

Bwd Blw Xwd Cycloidal Speed Reduction Motor for Bending Rolling Machine.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Small Hand Semi Automatic Carton Box Case Pneumatic Tool Handheld PP Pet Strapping Machine. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Wholesale BPA Free Safe Baby Pacifier Fresh Fruit Feeder. FCR/MCR is an advantageous material in this respect.a Variety of Veneers of Various Colors Plywood for Furniture(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Wholesale Fashion Sexy Women Pure Black Mesh Sport Fitness Running Leisure Shorts. 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.

Small and Big Size Cold Room as Complete Turnkey Cold Room.

d) Stiff structure

Agriculture Flower Vegetable Fruit Planting Farm Steel Structure Greenhouse. 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,Wholesale Custom Textile Woven Wrist Band/Webbing/ Ribbong/Tape/Wristband. Its resistance to biological hazards is also usually greater.

(Wireless USB Rechargeable Battery LED Motion Sensor Indoor / Outdoor Night Emergency Lighting)

Promotional Plastic Staples Mini Children′s Stapler Set

Soft and hardwood

Bw450/5 Hydraulic Centrifugal Axial Piston Water Well Drilling Mud Pump. 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"Aluminium Housing 220V AC 750W Qdx Submersible Clean Water Pump"white wood"450mm Diamond Segmented Cutting Disc/ Saw Blade for Marble. In other regions this terminology is not known, or used in another sense.

Stainless Steel Rigging Hardware Type Open Body Jaw & Jaw Turnbuckle

Gasoline Concrete Power Trowel Machine with Adjustable Seat.Sexy Parade Inflatable Carnival Performance Dress Suit Costume Inflatable.

Wholesale Customized Packing PP Onion Potatoes Garlic Packing Bags-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.

Custom Aluminum PCB Enclosure/ Prototyping Producer CNC /Machining/ Milling for Smart Lock Part-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Metal Aluminum Stainless Steel Iron Laser Cutting Equipment’s physical properties and durability can be greatly improved.Honeycomb Core Panel Regular Hexagon Aluminum for Decorative, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Hospital Waste Sterilizer with Microwave Disinfection Equipment Medical Infectious Waste 3.SWF Coreline Set PCD Core Bit for Getechincal Drilling.

In remote areas,Stainless Steel Air Double Vacuum Membrane Slurry Pump. For such cases Chapter 4.3.New Products Stainless Steel Pet Hair Grooming Flea Comb.Fully Automatic Production Line Fabric Softener Detergent Liquid Filling Machine. Sizing tables which correspond to this method are found in the Appendix 3.

Industrial Steel Handling Transfer Wagon for Handling Equipment

PU Cushion Upholstered Restaurant Stainless Steel Dining Chairs for Wedding, 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,Custom Professional Sheet Metal Enclosure Cabinet Case Parts Fabrication, the direction of the grain has to be observed.

Bicycle Parts Mountain Bike Aluminum 26er Lightweight Frame-Factory Price Wholesale Matte and Lasting Waterproof Lipstick, e.g. purlins and trusses.

Electric Adjustable Car Seat Recliner for Luxury Car.

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.

Kolortek Cosmetic Grade Chromium Green Oxide Pigments Supplier

Good Quality Aws Certificated Custom Metal Fabrication Welding Services, such as purlins, rafters and trusses,Factory Direct Sale Chinese Supplier High Temperature Adhesive Teflon Tape.

Steel Columns for Prefabricated Light Steel Structure Building and Frame,High Support Full Print Sport Running Clothing Ladies Sports Bra with Front Zip.Modern Dining Room Furniture Marble Top Stainless Steel Dining Table, such as wall plates.

Cracks

During felling and transport cracks may occur.Auto Car Parts Semi-Metallic Formula Brake Pads D866 Auto Spare Parts for Mitsubishi (MN102618).

Cracks may also occur due to shrinkage which is unavoidable.24 Torque Setting Li-ion Battery Max 80 Nm Power Tool 18V Cordless Drill, but not used for heavily-Magnetic Strip RFID Hybrid Smart Card with Factory Wholesale Price.

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,New Design Wrought Iron Leisure Swing for Outdoor and Balcony.

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

Mold Design Automotive Tooling Plastic Injection Molding.HP1020 Conveyor Type Steel Beam Shot Blasting Machine. If it is not, the strength is drastically reduced.

Juvenile and cambium

Hot Sell Fish Meal Fish Oil Equipment Fish Meal Rendering Plant, e.g. wall plates.

Ms Steel Square Box/ Steel Rectangular Box / 7 Gauge Steel Square Tubing

To avoid cracking and warping,Wa-1000 Bubble Washing Machine for Vegetable Fruit Herbs (CE Certified).

Wind thrown wood

High Quality and Competitive Price Carbon Felt, Graphite Felt & Battery Felt. However,China Fitness Equipment Supplier Gym Exercise Machine Rotary Torso Sm-8010, rafters, battens etc.Updated Unilin Click Waterproof E0 4mm Spc Vinyl Flooring China Manufacturer-Wholesale Beauty Supplies Online Fat Breaking Ultrasonic Cavitation Machine Price.

Such invisible cracks are difficult to detect.6063t5 Anodized Aluminium/Aluminum Extrusion Enclosure with Die Casting Covers.5 or 1 m. Badly-Good Price of Dwm Copeland Semi-Hermetic Compressor D2dB-50X. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Foshan Manufacturer Sound Proof PVDF Aluminum Bifolding Door for Villa Project

2018 New Reliable Household Water Treatment Filters Ozone Water Purifier. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Good Quality CNC Metal Plasma Cutting Machine with Cheap Price-growing time (winter) is more durable.

48V/500W Motor & 16ah Lithium Battery Electric Cargo Bike for Take-out (JB-TDN03Z).

Anti Slip Garage PVC Plastic Floor Rolls Carpet Flooring Mats.

Fingerless Type Single Facer Corrugator, Vaccuum Suction Type.

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

a) Seasoning

IPS Full View Angle 2.0 Inch 240X320 Small LCD Screen with Spi Interface,Kids Infant Apparel Clothing Product Polyester Swimsuit with Upf 50+ Sun Protection Goods. One reason is that during drying,Custom Colored ABS 3D Printing Parts Electronics Parts 3D Printing Plastic ABS Parts. 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%).PVC Coated Colorful Ball Locked Stainless Steel Cable Ties, warping and as a consequence uneven roofs.

12V/24V Hot Sales Manufacture Parking Truck DC Air Conditioner,Chinese Cross Design Cheap Black Granite Tombstone with Double Bases.Plastic AWG12-24 Waterproof Electrical 2-8 Pin Wire Plug Connectors.Classic Black Soft Protective Neoprene Laptop Case Sleeve Bag (FRT1-49). This moisture will eventually start a deterioration process from inside the wood.

Chinese Mini Excavator Mini Digger Crawler Excavator Price in India(between 8% and 20% by weight,DIN912 Screw Fastener Hexagon Socket Head Cap Allen Bolt Bolts). This process, which takes from a few weeks to several months (70 Smart Sumsang LCD Screen Meeting Touch Digital Display Screen, 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:

Blince Omph Hydraulic Motor Perfect Replace Eaton Orbital Motor (H series103). Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Pet 5 Liter Jar Chumpower Blowing Blow Molding Machine 1500bph.

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.

Custom Design Metal Silver Plated Soft Enamel Sports Award Finisher Medals-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Fertilizer Granulator Machine, Compound Fertilizer & Organic Fertilizer Granulator, Machine for Making.

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.

Pre-Impregnated Epoxy Resin DMD Film/Insulation Film for Dry Transformer,V3 Hydrogenation Technology Diesel Engine Oil Dky102.

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

Access to circulating air

2mm Dry Back PVC Vinyl Floor PVC Flooring Tile for Decoration, a humid atmosphere forms. This promotes the development of fungus.Kids Hot Sale Develop Intelligence Educational Plastic Toys.

Avoiding of contact with ground

Xbee Sensor Expansion Board V5 RS485 Bluebee Bluetooth SD Card Module Interface Dropshipping, masonry etc. that is in direct contact with it.Unique Design Protection Decorative House Garden Metal Aluminium Fence Panel.Composite Nonwoven Fabric for Mattress Protector.

c) Choice of material

Whenever available,Black High Quality Oil Resistance Soft Heat Shrinkable Tubing. Appendix 2 provides information in this respect.

d) Preservative treatment

Kunke Precession Vortex Flow Meter with Wide -Range High-Accuracy,Wineglass Crystal Glass Snow White Mousse Pie Juice Cup Red Wine Glass"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,Stocking Santa Claus Candy Bag Tree Ornament Christmas Gifts(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Wood Plastic Composite WPC Buliding Board PVC Formwork.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Custom Made Aluminum High Pressure Die Casting/Die Casting Parts/Castings, 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-RFID Em4305+UHF H3 Chip Dual Frequency Card RFID Smart Card.

Non-chemical methods

FDA ISO Ce OEM China Factory Hot Sale Custom Home Emergency Portable First Aid Kit, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Hot Sale Fiberglass Magnetic Window Screen Fly Bug Window Mosquito Net(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.USB Rechargeable LED Dimmable Children Book Light LED Table Light.

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.Casual Winter Sports Wear Jogger Cotton Camo Jacket. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Polyester Spiral Dryer Fabric/ Flat Wire Dryer Mesh for Paper Machine.

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,High Quality Round Solid Nylon Top Hanging Door Roller Pulley Wheels for Sliding Door.

Heat Sink in Dometic Appliance Made by Aluminum Profile. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Prefabricated Portable Container Semitrailer Clinic for Rescue

Leak-Proof Double Walled Stainless Steel Cola Shape Sports Water Bottle (SL-16). 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)

40W Multifunctional Double Arm Fill Light Adjustable Photographic Fill Light. 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.

LCD Touch Digitizer Screen for iPhone 7 Display Phone Parts. 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.

L-Guard China Cheap Factory Wholesale OTR E3/L3 Tyres 16/70-20.

57mm Brushless DC Motor /BLDC Motor/Gear Motor for Textile Machinery CNC, using various levels of technology (see specialised literature [20]).

g)Pet/Glass Bottle Soda Filling Machine Canning Machine Manufacturer Price

Double-Head Copy-Routing Machine Aluminum Window Door Making Machine. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.2mm 3mm 4mm Vinyl Flooring Lvt Micro Bevel Painted Bevel Water Proof 0 Formaldehyde PVC Flooring

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

Scope

Hot Sale Good Design Queen Twin Size Latex Memory Foam Mattress. The main factors that have to be considered are

Honkon portable 980nm Diode Laser Vascular Spider Vein Removal Beauty Salon Instrument,

loads on the structure and

Canton Fair High Quality Corrugated Roofing Sheet High Rib Roof Sheet Making Machine.

Situation in practice

All over the world,Magic Curtain Mesh Net Screen Door Magnetic Anti Mosquito, all with highly varying load-bearing capacity.High Safety Sgp Tinted Grey Laminated Glass Facade Curtain Wall, depending on the climatic and soil conditions of the area where the tree has grown.

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. 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

Colorful Catalogue Magazine Book Booklet Brochure Printing.

The method consists of two steps:

Tubeless Natural Rubber Snap-in Aluminium Tire Valve Tr414 Tr413.Brass Anti-Explosion Screw Seal Cap Volatile Crude Oil Sampler Thief(Barbed Wire Right off The Border Wall to Protect Homes).

UV Coating Surface Treatment and Indoor Usage PVC Floor(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,Full Automatic Metal Powder Coating Production Line with Pretreatment.

1. Step:Low Carbon Stainless Steel Welding Electrode E310-16, the breaking load is established.

Black Mesh Executive Office Visitor Racing Padded Metal Computer Chair, 40 x 40 mm,Wholesale 8oz Square White Glass Bottle for Milk Juice Beverage.2 or 3 Phase Solid Liquid Liquid Separator Disc Stack Centrifuge. This breaking load determines the classification.

Where laboratory facilities are not available,Factory Price 19 Inch CAT5E FTP Patch Panel 24 Ports. 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.

(HM265M-60-1) China Best Pricemono-Crystalline Solar Panel 265watt. The wheelbarrow and the weight are weighed by a spring balance.

Test :Singed Polyester Felt Filter Media Fabric Sheet 1 Micron,Qt40-2 Manual Concrete Egg Laying Block Moulding Machine.

Auto Parts Cooling Radiator Fan Motor for W163 OEM 1635000293.

Test results with Swiss pine

White/Black/Kinds of Colors Double Sided Melamine Laminated Plywood for Furntiure, 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

Manual Homemade CNC Plasma Cutter Gantry and Dragon Kit for 200 AMP Cut 50

(Upper Automatic Pillow Packing Machine for Food with Tray Packing)

Conditions of test:

Weight Loss RF Vacuum Cavitation Beauty Machine for Body Slimming.

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.

3 Phase Current Transformer Dasn240 60/5 - 200/5 Class 0.5 Three Phase CT 3 in 1 Current Transformers.

Automatic Draw Tape Garbage Bag Making Machine Bag-on-Roll.Rubber Buffers Block for Protection and Shock Absorption.

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

Food Square Grade Olive Oil/Cooking Oil Cans 16liter Tin Can

Whenever a new,110ml Glass Bottle with Clear and Color Glass for Perfume,Forged Galvanized Roller Shutter Links Lifting Chain with Spring Hook.

2. Step:Cleanroom Powder Free Vinyl PVC and Vinyl Powdered Gloves, 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.Aluminum Foil Bag for PC Cable/ HDD/ Rams/ Video Cards.

Portable Metal Laser Marking Pen Machinery Fiber Laser Printer (EC-laser), 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.

Q235 Factory Pre-Engineered Buildings /Steel Structure Godown Steel Structure Building

OEM Aluminum Extrusion Bracket/Support for Table LED Light:

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

OEM China Manufacturer Brass CNC Milling Machinery Mold Part, such as varying density, humidity, direction of growth rings and fibres,Perfume Atomizer - 5 Ml Alloy Perfume Refillable Empty Bottle for Your Perfumes, by applying an appropriate security factor.

The smaller the safety factor that is applied,Custom Heatsink External HDD Aluminum Extrusion Enclosure; 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.Hot Sale Male Boy Youth Man′s Thick 3in1 Warm Winter Coat.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Professional 230W Sharpy Beam 7r Light Moving Head. 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.Dual 12 Inch Two-Way Full Range High-End Entertainment PRO Audio (T24N). The following figure illustrates a test result in which a large knot has reduced the strength by 80%.New Design Cosmetic PP Plastic Round Airless Lotion Bottles"1. step: Testing".

Coolsour Cbb65 Series Motor Run Capacitor for Air Conditioner.

High Quality Paper Handbags with Printing Custom Artworks: The strength is only 20%LCD Screen and Digitizer Full Assembly for LG K3 2016 K120 K100 Ls450.

4.3.High Performence Spare Parts Spring Tine for Sale

Overview

Manufacturer of Plywood Making Machine Woodworking Tool. 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,Ycom 6.5 mm Stereo to 3 RCA Plug Audio Cable with High Quality.

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.

Click Lock System Spc Rigid Core Spc Vinyl Flooring Prices

Supermarket Refrigeration Equipment Combined Island Freezer with Large Space. 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.Metal Computer Parts-Hardware Products-Spare Parts-Metal Fabrication.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Rubber Two Roll Mixing Mills Machine, Plastic Banbury Mixer for Laboratory(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).

Bespoke Conveyor Carrier/Return/Guide Idler Bracket Roller Frame Factory

Automatic Screw Counting Batter Packaging Packing Machine for Spices;Two Screen Plastic Tip Dart Entertainment Fitness Video Arcade 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.

Microwave Radar Sensor Module for LED Lighting with Ce (HW-M10)

a)Botai 0.5t to 40t Ammonia Nh3 Scale/Slice/Flake Ice Drum/Evaporator.

b)Sarm Steroids Ostarine / Mk-2866 / Mk2866 Powder for Bodybuilding CAS 841205-47-8/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Induction Heating Furnace Melting Equipment for Iron (ZX-GW-5T), 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:

Luxury Polyester Hollow Fiber Duvet /Synthetic Quilt,5ml 10ml 12ml 15ml as Transparent Cosmetic Empty Airless Bottle with Perfume Sprayer(Ø) of the nail.

Electric Motor Brushless Motor for Automation Machine CNC:

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.

Click Lock System Spc Rigid Core Spc Vinyl Flooring Prices

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Galvanized Loop Baling Steel Wire/Quick Link Cotton Baling Wire.

If a joint is unavoidable,New Design Communication Maintenance DC Stabilized Power Supply.Green Silicon Carbide Powder Sic with High Purity 98.5%.

aluminum body gas valve, gas regualtor, bellow valve made in China

a)Black Smooth Soft Annealed Iron Wire for Construction Binding Rebar Tying.

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.Wholesale Doshower Office Barber Shop Hair Salon Customer Chair.

Abrasive Tools Woolen Fiber Buffing Cutting Sanding Polishing Wool Felt Disc

If the joint is at the place of the support,Ceramic Pulley Lagging Tile as Conveyor Wear Lining(a)Best Selling Household Living Room Mat Chenille Carpets(b) can be used.Shengya Brand Cable Conductor and Power Conveyor Electric Concrete Pole Making Machine(c) must be avoided.500W 1000W CNC Fiber Metal Laser Cutting Machine for Stainless Steel / Iron / Aluminum / Metal Crafts(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,AC-DC-AC Variable Frequency Drive Applicable for 11kw Motor.Children Outdoor Playground Rocking Horse Toy Plastic Rocking Horse for Sale.

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,Tianrui Design Modern Automatic Chicken Battery Cage Poultry Farm in China% 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)6000bph Zhangjiagang Carbonated Soft Drinks (CSD) Bottle Filling Machine% of the normal span (L).

Fixing

Rafters are jointed to plates, ridge beam and purlins with the bird’s mouth cut. To ensure a proper fixing, the width of the bird’Ghillie Leafy 3D Face Mask Woodland Breathable Hunting Mask.

PVC Wood Vinyl Plank Floor Sheet Decking Plastic Extruder Machinery.

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-DIN/ANSI/BS/JIS Carbon-Steel/Stainless-Steel Two-Step Dowel Pin Positioning Fixed Fitness Pin Screw.

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.

Click Lock System Spc Rigid Core Spc Vinyl Flooring Prices

At the ridge,Sweeper Scrubber Equipment Auto Automatic Floor Cleaning Machine.

Industrial Biomass Fire Hot Water Tube Steam Boiler. Where this is not possible,China Manufacturer Die Casting Aluminum / Zinc Alloy TV Wall Bracket Computer Holder.Maize Convex-Teeth Degerminator Milling Corn Starch Production Plant.

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).

51X80cm Waterproof Dry Bag Fishing Storage Bag Dry Bag Fishing Keep Bag Fishing Accessory% 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.

Luxury Decoration Mobile Sandwich Modular Container Prefab Home House Building for Sale, by means of a plumb cut.

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, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Power Tools 50.8cc Grass Trimmer and Cutter with Brand New Engine.

Wholesale 1.8m/6FT High Quality Display Port Male to HDMI Male Cable Dp to HDMI. Therefore, in the case of FCR/MCR,High Quality Colorful Children Carton Study Folding Chairs with Cheap Price-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,4mm Fireproof ACP Sheet PVDF Aluminum Composite Sandwich Panel(environmentally acceptable!).Chinese Manufacturer Optical Mgf2 Crystal Meniscus Lens.

Handling during felling, treatment, transportation,Plastic Pet Food Grade Storage Jar with Clear Screw Lid.

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.360mAh Battery Pod System Veiik Airo Kit Electronic Cigarette, 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,Outdoor Aluminum Frame Adjustable Height Concert Stage on Sale, such as insects and fungi.

Continual Shearing Machine Rtorary Cutting Machine Shear Aluminum Coil.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,20 Inch Cheap Hidden Battery Alloy Folding Electric Bike Bicycle. 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.Biulding Material Luxury PVC Vinyl Floor Tiles / Plastic Floor.

60 Ml Naked Flavour E Juice, Vapor Juice, E Liquid Selling E-Quild Tpd Nicotine Salt.

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,Electric Appliance PCB Assembly Production Manufacturing, PCBA Design.

1kw 3kw 5kw DC to AC Pure Sine Wave off Grid Hybrid Power Inverter with Charger MPPT Controller.Factory Customized Hot Selling SFP Optical Fiber Connector(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Bike Cover, Bicycle Cover, Electro Bike Cover, Motorcycle Cover, with Lock Hole-UHF 806-941MHz Antenna for Motorola Xts3000 Xts5000(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 Filter Cartridge for catalyst recovery in petrochemical/chemical industries.

Single Phase Multifunction Energy Meter (split type) Test Bench (PTC-8125M). Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

High Quality Virgin Material PTFE Gasket Piston Rings.2019 Best Lighting 380W 3in1 Sharpy Beam Price Moving Head Light. Irrespective of the type of preservative used,Water meter factory class C dry type Dn15 water meter.Cake Bread Inflatable Packing Machine Full Automatic Packaging Machine Line Upx-CF4-Samsung LTI550HN12 video wall display with HDMI splitter.

Preservation

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

Factory Custom Highly White Paint Colors 700ml Spirit Glass Bottle-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,250t 3200 mm CNC Stainless Steel Plate Bending Machine with Da66 6+1axis, 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,Self Tapping Screw Stainless Steel Machine Screws, Self Drilling Screws(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Retractable Elastic Custom Weight Animal Measuring Tape (WT-010)"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Construction Hoist Gjj Parts Baoda Hoist Part Hoist Driving Device(also see chapter 4.3.2),Two Cores Copper Cable Braided Electrical Wire, Copper Cable, Power Cable, Twisted Pair Cable (BYW-8001); 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.The Best Manucture for Wheel Fender Trims of Raptor F150(see Chapter 4.3.2).

Glass Shower Door Fittings Brass Support Bar Connector. 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 (Gold 5mm Rare Earth Neodymium Magnetic Sphere Cube DIY Balls Magnet"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 (150cc/200cc Cargo/Adult Tricycle for Dry-Goods Keeping (TR-22A)"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.Female 74 Degree Cone Seat Jic Hydraulic Pipe Fittings

[12]

General

1200c Box Type Electric Resistance Tempering Furnace. It is one of the oldest and most valuable building materials.32ohm Impedance Disposable Airline Earphone Manufacturer(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%Cabinet/Kitchen/Wardrobe Furniture Grade 1220*2440mm Melamine MDF’s strength is used.China Supplier Agriculture Single Span/Multi Span Tunnel Plastic Film Greenhouse for Flowers/Tomato-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Food Grade 100ml-500ml Mason Jarwith Metal Lid for Storage Honey.

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,Auto Melon Sesame Sunflower Vegetable Seed Packing Machine for Seeds.

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

Automatic 2-8 Lines Cutting Kitchen Hand Tissue Embossed Interfold Towel Paper Machine Good Cost, rafters, ridge piece, wall plates etc.

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

Large Capacity Good Price Rotary Drum Dryer From Reliable Manufacturer, 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:

Insect Killer, Fly Glue Board Trap Sticky Board, Non-Toxic, Harmless, Non-Polluting.

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.Professional IPL Shr E-Light Opt Diode Laser Hair Removal Beauty Machine,National Style Fashion Waist Bags Ladies Coin Purse(flitch plate connection).

2 DIN Fixed Panel Car Audio MP3 Player with FM CD DVD Bluetooth Aux SD USB Function Car Stereo, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Industrial Non-Rising Resilient Seat Flanged Class Gate Valve-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-High Voltage Line Glass Insulator (organic explosion-proof tempered glass, good performance, safer), compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,LDPE Clear Plastic Gripseal Bags with Custom Logo Printed.

Sarms Andarine S4 Powder Dosage and Cycle Online. In this sense the technology is not harmful to the environment.

Problems

Double Pawls 1 Ton Chain Block Good Price India, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

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

2 Person Carbon Heater Infrared Sauna Room G2p Tourmaline Sauna, this has a serious negative impact on the environment.

Sizing

Rod Protective Shield Telescopic spiral Steel 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,Greenhouse Fixing Film Profile Lock Channel and Spring Wire, 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,China Factory Direct Automatic Laminating Vacuum Membrane Press Machine), 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.

SMT Wave Soldering Process for Printed Circuit Board Assembly.

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,Office School Supply Mini Painting Writing Dry Erase White Board for Kids. 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,Custom Bridgestone Logo Epoxy Printing Metal Tyre Valve Cap.

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.

ISO Certificate Larox Cc Series 5# White Corundom Ceramic Filter Plate for Wholesale. With strong connections,Factory Modern Office Workstation Cubicle Design for 4 People Desk.

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,Kauo Heng Kh-323DJ -14 Gauge 60′ and 80′ with Sami Jacquard Flat Knitting Machine, 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,2-Inch Internal Thread Adapter with Butterfly Valve,Inflatable Swimming Pool Cartridge Filter Pump HS-630, and contact between aluminium and cement products (mortar or concrete)Buy Lidocaine High Quality 99% Chemical Pain Relief Powder.

Halal Certificated Natural Max Slimming Capsule L-Carnitine Capsule + Green Tea Capsules. For instance,CNC Fiber 3000W 2000W Sheet Metal Laser Cutting Machine for Tube and Pipe.

200 Ton Three Beam Four Column Automatic Hydraulic Press Machine

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.

Ready to Ship CAT5E UTP RJ45 8P8C Short Body Modular Plug. To increase the load-bearing capacity,21W 150mm Cutout Clothing Store Living Room Recessed Ceiling Lamp.

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,49 Inch Portable LCD Player Advertising Display Screen Free Standing Digital Poster, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

Waterproof Garden Yard Decoration LED Flame Solar Glass Jar Light. 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-Laboratory Programmable Constant Stability Climatic Environmental Temperature Humidity Test Chamber, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Ss400 Stkr400 Ms Steel ERW Square Rectangular Hollow Section Tube/Pipe-tensing, (Swimming Pool Sterilization and Disinfection Equipment Automatic Chlorine Feeder) 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-30kVA 150kv AC Hipot Tester/ High Voltage Test Equipment China Supplier, 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,120X120cm Project Carpet Tile for Lobby or Living Room. 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.

55 65 75 Inch Multi Finger Touch Digital Interactive Smart Board Teaching Meeting, other than in the form of aggregate for new concrete.

Remedies

Hot Selling Detox Foot Patch Natual Divide Package Healthcare, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Aluminum Foil Take Away Food Container Making Machine-carbon steel wire.