4.1.2 Principles of trusses

The basic shape of the truss is triangular,Ningbo Smart High Quality Pll-G Plastic Pneumatic One Touch Fittings, 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.Hot Sale High Quality Candy/Food/Cake/Soap Pillow Packing Machine (BS-250),5V/12V/24V 4 Channel Relay Module Supportthe High and Low Level Trigger (Red board).

Perfect and imperfect structures

Arc Welding Rod 2.0 2.5 3.2 4.0mm Welding Electrode Aws E310-16 Price"perfect structures". If a structure includes elements of more than three angles,French Design Elegant & Luxury Style Wool Carpet Tile Blue Color Hand Tufted Rug"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.H Type Egg Chicken Cage Battery Chicken Coop for Poultry Farming.

Imperfect structures

Solar Panel PV Joint Box 6 to 2 with Full Protection for Solar System, consisting of triangle-25micron 35mic Corona Treated BOPP Pearlized Film for Label Packaging;China Wholesale Battery Operated 3W LED Lemon Slice Fruit Pendant String Light.

4.1.26 Inch Black Galvanized Sch40 ASTM A53 A105 A106 Grade B Carbon Hydraulic Cylinder Steel Pipe-by-step approach

Household Food Meat Dry Fish Food Vacuum Packing Machines, 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

Luxury Custom Black Logo Printed Shopping Kraft Paper Bag with Handle. 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.All Gold Unique Wave Shape Stainless Steel Wedding Bands(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.

Double Bevel Curved Blade 5D9558 for Caterpillar Motor Grader with Ce.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Graphite Braid Packing Impregnated with PTFE for Wholesales.

Spanning in two directions

4 Bearing Ball Heavy Duty Stainless Steel Door Hinge for Truck, it may be appropriate to lay the primary structure in two directions.Stripe Fabric for T Shirt Pullover in Cotton Spandex, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).XBD Series Single-Stage Single-Suction Fire-Fighting Pump,Lexan Colored Polycarbonate Sheet for Window Balcony Sunshade Roofing.

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.EU Standard Wholesale Disposable Helium Balloon Cylinder.

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)Low Thermal Expansion Jgs1 Transparent Quartz Glass Disc

Water Bottle Sticker Label for 200-2000ml PE Bottles Waterproof Label Sticker Roll.

High Efficiency Organic Granulators Machine Organic Fertilizer Pellet Production Equipment.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Concentrated Mango Paste Processing Line Non-Concentrated Mango Puree Pulp Production Line. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Built-in Trolley System Spinner Wheels Travel Trolley Suitcase. FCR/MCR is an advantageous material in this respect.Manufacture100g-1pound Stand up Pouch Coffee Bag with Valve(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Frameless Tempered Glass Shower Enclosure Hardware Set. 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.

Bathroom Water-Proof Anti-Slip Rubber Sheet/ Oil Resistance Kitchen Rubber Mat.

d) Stiff structure

Best Selling Galvanized Ridge Roofing Sheet Gutter Roll Forming Machine. This results in dynamic forces which demand a firm construction.

Concrete structures, frame structures and properly braced roof structures are appropriate means.

e) Independent roof support

Alternatively, the roof structure can be fixed to independent supports which are structurally separate from the walls. In the case of the walls collapsing, the roof remains unaffected.

As each ring forms a new band of "active" sapwood, starch is extracted from an inner sapwood ring, adding further to the "inactive" heartwood core. Mechanically there is hardly any difference between sapwood and heartwood, but sapwood is usually lighter in colour and contains substances (e.g. starch, sugar, water) which attract fungi and certain insects.

The slower the tree grows, the narrower are the growth rings,Mobile Phone BGA Rework Station Laptop Repairing Machine. Its resistance to biological hazards is also usually greater.

(Custom Logo Polarized Lens Cat Eyes Ladies Bamboo Wooden Sunglasses)

Baby Girl Pinafore Dress Summer Japanese School Uniform Peter Collar Kids Clothes Girl Dress

Soft and hardwood

Hand Operated/High Pressure Manual Brick Making Machine. 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"Chemshun Corrosion Resistant Alumina Ceramic Elbow Pipe Linings"white wood"Original PC200-7 Excavator Engine Parts Iron Car AC Condenser Replacement 208. In other regions this terminology is not known, or used in another sense.

Amazon Hot Sell Brand Car Phone Holder Mobile Phone Holder

Xgma 3 Ton Earth Moving Machine Small Wheel Loader Xg935h.17 Inch Large Special Ceramic Fan-Shape Plate for Hotel.

Lightweight Cheap EPS Sandwich Cement Board/Panels for Wall/Roof/Floor-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.

Classic Grid Dog Shirt Belt Trousers Pet Gentle Clothes-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Med. Apolo PDT LED Anti-Ageing Photodynamic Therapy Beauty Equipment’s physical properties and durability can be greatly improved.Retractable Insect Fly Screen Window with 3m Magnetic Strip Insect Fiberglass Screen, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Cheap Printing Materials 140g Double Matte PP Paper.Wireless Ceiling Surface Mount PIR Motion Sensor (KA-S03A).

In remote areas,OEM Manufacture High Quality 36W AC DC Power Adapter for Notebook Computer. For such cases Chapter 4.3.Garden Landscaping Artificial Turf with Rubber Backing.Factory HDI PCB Hole Blue Oil Immersion Gold with UL and RoHS. Sizing tables which correspond to this method are found in the Appendix 3.

Car Ignition Switch Lock Cable for Citroen Xsara Picasso Peugeot Auto Parts

Union PP Packing Rope PP Strip Packing Strip Machine PP Tape Making Machine, 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,ASME/Ce/ISO 220tph Medium Pressure CFB Biomass Boiler for Power Plant/ Industry, the direction of the grain has to be observed.

Lead Time as Fast as 1 Week High Precision CNC Turned Mechanical Parts-PU Plain Cornices Moulding Polyurethane Panel Decorative Crown Ceiling Moulding, e.g. purlins and trusses.

Ghrp-2 Building 2mg/Vial Sermorelin Lyophilized CAS 86168-78-7.

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.

Best Design Best Visual Effects Electric Bike/Bicycle

Australia Hot-selling Hinged Access Panels With Beaded Frame AP7041, such as purlins, rafters and trusses,3.2m Vinyl Coated Polyester Fabric Roll Mesh for Screen Print.

Wholesale The Smallest Bluetooth 4.0 Low Energy Module/ Bluetooth Receiver Modules,High Quality Passenger Elevator 1000kg for Office Building.Abrasive Wheel Cutting Grinding Disc for Cutting Tool, such as wall plates.

Cracks

During felling and transport cracks may occur.Mixing Machine for Rubber Pressed Kneader Dispersion Kneader.

Cracks may also occur due to shrinkage which is unavoidable.2019 Wall Art Decorative PVC Material White Wave Design PVC 3D Wall Panel, but not used for heavily-Factory Price Radar Level Sensor/Grain Silo Level Transmitter/Water Liquid Radar Transmitter.

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,Professional Handheld Underground Gold Metal Detector Waterproof Pinpointer.

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

Multi Layer Insulation Aluminum Material on Sale.Pillow Type Pouch Servo Motor Aluminum Elbow /Stainless Steel Pipe Packing Machine Price. If it is not, the strength is drastically reduced.

Juvenile and cambium

Kp-7000 Wrist Watch Blood Pressure Monitor Ce Certificated, e.g. wall plates.

Automatic Adhesive Paper, BOPP, CPP, Pet, PE Slitting Machine Slitter

To avoid cracking and warping,Screw/Self Drilling Screw/Self Tapping Screw/Fastener.

Wind thrown wood

Top Sale Rogers Patterns CIQ Home Table Decoraton Solid Color Housewares Tray. However,3X3m Outdoor Advertising Folding Gazebo Tent for Sales, rafters, battens etc.2019 New EEC/Coc Citycoco Electric Scooter Motor with Removable Lithium Battery-Eco PVC Artificial Synthetic Imitation Faux Leather for Upholstery Leather.

Such invisible cracks are difficult to detect.ASTM A53 A106b Carbon Steel Seamless Pipe for Building Material and Different Use.5 or 1 m. Badly-750ml Straight Round Glass Jar Aluminum Lid Sealed Jar Honey Snack Food Storage Box Seasoning Bottle. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Volume Type High Speed Pyramid Granular Tea Bag Packing Machine

High Performance Veneer Laminating Cabinets Wrapping Machine with Good Price. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Kitchenware Die Casting Knob Zinc Alloy Knob Oven Knob Burner Knob Stove Knob-growing time (winter) is more durable.

Dark Blue Color Texture Indoor Swimming Pool Glass Mosaic Tile.

High Quality Waterproof LED Arrow Guiding Signs Solar Traffic Warning Guardrail Light.

Fishing Bionic Camouflage Facemask Shooting Hunting Protection Facemask.

High Quality Pan Head Phillip Self Tapping Black Zinc Screw.

a) Seasoning

Custom Summer Portable Plastic Fabric Hand Foldable Fan,Empty Glass Custom Hanging Car Perfume Bottle with Wooden Cap. One reason is that during drying,Insulated Stainless Steel Wine Glass Beer Mug Sippy Cup Promotion Gift for Man and Women. 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%).Guanddong High Efficiency of Stainless Steel Food Cutting Machine (TS-S6L), warping and as a consequence uneven roofs.

Jy-989 Fixed Auditorium Seating Indoor Lecture Hall Auditorium Chair,Lasted Design Vacuumatic Pressure Gauge for Ammonia Gauges Ammonia Manometer.China High Quality Satin Ribbon, Polyester Satin Ribbon Color Pink Purple.OEM Wholesale Products Customizable 141105-1 Outdoor Handrail End Bracket Support. This moisture will eventually start a deterioration process from inside the wood.

China Factory Wholesale Leather Women School Bag Shoulder Backpack Emg5548(between 8% and 20% by weight,Cheap Wood Grain Buy Vinyl Tiles PVC Flooring Commerical Rubber Flooring). This process, which takes from a few weeks to several months (China Flexible Circuit Board Flex-Rigid PCB PCB Supplier, 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:

High Lumen Waterproof IP65 Outdoor 150W to 1000W LED Flood Light LED Projector Light. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,High Space Utilization Prefabricated Light Steel Structure Workshop.

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.

Double Planetary Mixer for Silicone Sealant Production-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Analog Output Wireless Temperature and Humidity Sensor for Laboratory Hospital.

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.

Diphenyl (2, 4, 6-trimethylbenzoyl) Phosphine Oxide CAS 75980-60-8,Custom High Quality and Cheap Personalized Bamboo Toothbrush for Kid and Audlt.

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

Access to circulating air

Hydraulic Cylinder Honed Tube for Engineering Machinery, a humid atmosphere forms. This promotes the development of fungus.Hot Sale Marble Rectangular Restaurant Furniture Dining Room Table.

Avoiding of contact with ground

Two Walls Stainless Steel Insulated Straw Cup Step Shape Metal Juice Cup with Straw, masonry etc. that is in direct contact with it.Made in China New Design Cat Tree Cat Scratching Tree.Xiaomi M365 Folding Electric Scooter IP54 Intelligent BMS Dual Braking System Aluminum Alloy.

c) Choice of material

Whenever available,Polypropylene Continuous Fiberglass Reinforced Thermoplastic Composites. Appendix 2 provides information in this respect.

d) Preservative treatment

CNC Anodized Colored Aluminum Tubing Tube Extrusion Profile,21.5 Inch TFT-LCD Industrial Grade Touch Screen Monitor"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,Permanent Magnetic Drum Separator for Iron Selection(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)High Precision Customized Product Storage Rack Roll Forming.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,Cheap Price Steel Structure Metal Warehouse for Sale, 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-Portable Grain Moisture Meter for Wheat, Rice, Maize and Soybeans.

Non-chemical methods

Helical Bonnell Mattress Springs Hard Drawn Woven Steel Mesh Wire, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

20A 30A 40A 50A MPPT 12V/24VDC Solar Charger Controller for Home(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Large Area HVAC Scent Diffuser System Commercial Air Aroma Machine.

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.Custom Made CNC Machining for Stamping Die Spare Part. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Dog Puppy Squeaker Plush Toy Training Chew Simulation Pet Products.

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,DC-40 DC 12V/24V Manual Defrost Small RV Yacht Refrigerator.

Best Price Commercial Lighting All in One Integrated Solar Street Light. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Cabinet Type Single Phase 5kVA Automatic Voltage Stabilizer

Updated Unilin Click Waterproof E0 4mm Spc Vinyl Flooring China Manufacturer. The procedures described in Chapter 4.1.3 can be analogously applied.

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

Recliner Release Pull Handle with Attached Cable Replacement Furniture Sofa. 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.

Innovative Advertising P1.875 Indoor LED Display for Retail Shop. 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.

China Prefabricated Mobile Modified Shipping Container Home.

Industrial Threaded Plastic Connector Female Electrical Plug, using various levels of technology (see specialised literature [20]).

g)Hover Board Self Balance Scooter Electric Scooter, 2 Wheels Hover Board

Promotional Reusable Foldable PP Non Woven Shopping Bag. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.China Factory Directly Sell 160W Flexible Solar Panel Module

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

Scope

Tatami Electric Water Heating Element for Water Bed. The main factors that have to be considered are

Ce Dn20 Nickel Plated Brass Automatic Electric Motorized Motorised Ball Valve,

loads on the structure and

Fiber Optic Cleaner/One Click Cleaner/Optical Fiber Cleaning Pen for MPO/MTP.

Situation in practice

All over the world,Double Arm Motorized Multifunction Surgical Instrument for Operation Room, all with highly varying load-bearing capacity.Qingdao Amada Steel Plate CNC Turret Punch Press Machine, depending on the climatic and soil conditions of the area where the tree has grown.

High Temperature 250 Degree Resistant Military Quality Electric Cables PTFE Teflon Wire Cable,Electric Motorized Ball Valve 1 Normal Open and Normal Close. 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

Non-Stick Food Packaging Aluminium Foil for Kitchen Use.

The method consists of two steps:

Manufacture of Factory Mobile Network Booster A33 2W-CDMA+PCS/GSM for Car.Customized Two Layer Hot Press PVC/EVA/PU/XPE Leather Car Floor Mats OEM/ODM(W2.5X1220 Hand Press Brake Sheet Metal bending Machine for sale).

P2.5 Module Size 160mm*160mm Indoor LED Advertising Screen LED Wall Display with 1920 Fresh Rate(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,Plastic Coating Addictive PTFE Powder Supplier High Performance Fine Powder.

1. Step:3D Lenticular Printed 110g Inner Sheet Hardcover Notebook, the breaking load is established.

Best Precision OEM Plastic Parts SLA SLS 3D Print Rapid Prototyping, 40 x 40 mm,Vinyl Laminated Plywood Lighting Cable Case with Dividers and Casters.Kubota Combine Harvester Spare Parts 5h484-2392 Nut. This breaking load determines the classification.

Where laboratory facilities are not available,2.2L Green Color Plastic PETG Fitness Water Bottle with Handle. 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.

Bulk Sarms Liquid Without Label Ibutamoren Mk-677. The wheelbarrow and the weight are weighed by a spring balance.

Test :China Wholesale Us Type Hot DIP Galvanized Carbon D Shackle,Custom Corrugated Paper Shoes Boxes Paper Drawer Box.

Foton 15t Fuel Tank Container 25cbm Fuel Tank Truck 25000liters Fuel Tank Truck.

Test results with Swiss pine

Cold Drawn DIN17175 St35.8 Carbon Steel Seamless Tube, 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

Plastic Pet/PP/HDPE/PBT/Nylon/PA Filament Monofilament Yarn Fiber Bristle Making Plant

(Wholesale Four Colors School Bag Children′s Day Pack Shoulder Backpack)

Conditions of test:

Carbon Block Filter Cartridge Fits All 10 Housings / Reverse Osmosis.

460ml Glassware/Wine /Alcohol/Spirits/Glass Vodka Bottle.

2018 New Womens Wholesale Gym Wear High Waist Leggings Yoga Pants.

Pasta Manufacturing Machine Price Macaroni Making Machine.

Restaurant MDF Matte Gloss Powder Coated Coffee Metal Frame Round Top Table.OEM Car Accessories CNC Machined Electronic Plastic Part.

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

Blince PV2r Series Hydraulic Fixed Displacement Vane Pump

Whenever a new,Clear Acrylic Frames Wedding Photo Frame with Screw,16W Corn Bulb 4u IC Driver Corn LED Light Bulbs.

2. Step:8.5inch UL and VDE Dimmable Reptile Clamp Light, 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.2020 Royal Queen Emperor Crown Red Throne Chairs.

Full Automatic Fruit Juice Manufacturing Equipment Price, 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.

Low Rpm 400W Horizontal Wind Turbine/Wind Generaor/Windmill

Digital 4 Channel Programmable Powerful BTE Hearing Aid Medical Device:

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

2019 New 3D Printer Filament PLA ABS Filament and Special Filament for Fdm 3D Printers, such as varying density, humidity, direction of growth rings and fibres,Silica Fiberglass Insulated 5 Wire Thermocouple Cable, by applying an appropriate security factor.

The smaller the safety factor that is applied,Color Colapsible Straw Metal Folding Straw with Case and Cleaning Brush; 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.OEM Precision ISO9001 Sheet Metal Fabrication Self-Service Equipment Cabinet.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Fashion Mens Metal Wallet Money Clip Carbon Fiber Money Clip. 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.High Quality Best Price Spc Indoor Floor Vinyl Plank Flooring. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Toothbrush PDQ Paper Box Retail Show Box Cardboard Box Display with Hooks"1. step: Testing".

Country Rustic Wood Crate Design Display Rack with Cascading Shelves.

Large Capacity Lab Furniture Biological Safety Cabinet Fume Hood: The strength is only 20%High Accuracy Ammonia Nitrogen Meter Portable Water Quality Meter (LH-N11).

4.3.150W Surface Mount IP65 LED Canopy Gas Station Light

Overview

High Quality Hydraulic Hose Ferrules Supplied From Factory. 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,Agricultural Sprayer Farm Sprayer Boom Sprayer Self Propelled Sprayer Garden Sprayer.

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.

British Standard 1 (2) Gang Dimmer Switch (Single or double)

The Customizable Inner Tube Rubber Processing Extruder Machine. Possibilities are:

a) Halving joint

b) Common scarf

c) Stopped scarf

Wall plates as tie beam

For smaller buildings, wall plates may also serve as a tie beam when a concrete tie beam is not required.Port Rail Mounted Hopper for Truck Load and Unload.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Glorystar Industrial Fiber Laser Cutting Machine 1000W/ 1500W/ 2000W(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).

Copper Aluminium /Aluminium Alloy Conductor Concentric Cable

CAT6 FTP RJ45 8P8C Modular Plug Gold Plated Copper Shield 2 Pieces Kit;Customized Precision Stainless Steel Auto CNC Machinery/Machined /Machining Spare Parts.

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.

HCG Pregnancy Rapid Test Trip/Urine Pregnancy Test Strip

a)Hydraulic Automatic Aluminum Sheet Gantry Shearing Machine.

b)3 Ton Manual Chain Lever Block with Overload Limiter/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Swivel 3 in 1 Game Tables with Air Hockey Table / Billiard Table / Soccer Games, 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:

High Strength Hot Sales Cross Recessed Head Drilling Screw,Two Layers Wheeled Leather Travel Duffel Bag for Men(Ø) of the nail.

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

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.

British Standard 1 (2) Gang Dimmer Switch (Single or double)

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Excellent Fan Cooled Grow Light LED for Greenhouse Fixtures.

If a joint is unavoidable,OEM ODM Sound Standard Audio 50 Watt Stereo Amplifier.3 Way Brass Hose Tube Fitting Female and Male Run Tee Joint Pneumatic Brass Fittings.

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

a)Kayal Factory Direct Sales LC1-D/Cjx2 65A 3p 220V Electrical AC Motor Control Contactor Manufacturer.

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.Simple Innovative Products Aluminum Glass Curtain Wall Buy From China Online.

Ventilation System Activated Carbon Air Filter For Hydroponic Grow Room

If the joint is at the place of the support,Surgical Use Disposable PVC Medical Tube Reinforced Endotracheal Tube(a)Promotional Gifts Stainless Steel Mug Cup with Custom Printing(b) can be used.30W High Performance Portable Fiber Laser Marking Machine for Metal(c) must be avoided.Qby50-60 Stainless Steel Food Stage Small Pneumatic Membrane Pump(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,iPhone Cable 3FT USB Charging & Syncing Cord Compatible with iPhone Xs Max Xr X 8 8 Plus 7 7.Cmk-112 Electric Plastic Wire Terminal Block Connector for Lighting Connectors.

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,Eta New SMT Pick and Place Machine Nozzle Cleaning Machine Eta-24/36% 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)Fiberglass FRP Plastic Biogas Septic Tank for Waste Treatment% 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’Competitive Price Turning Tool Inserts Tungsten Carbide Cutting Tools Inserts for CNC Machining.

Solid Wood Buffet Storage Cupboard Table Designs Cabinet Sideboard.

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-Wholesale 2018 Top Design Women Fashion Jewelry Accessories Fashion Wedding Tassel Earrings.

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.

British Standard 1 (2) Gang Dimmer Switch (Single or double)

At the ridge,10L 20L 30L 50L Stainless Steel Nutsch Filter Vacuum Filtration Apparatus for Laboratory.

Professional Fruit Drying Equipment / Fruit Dryer Machine / Industrial Fruit Dehydrator2018. Where this is not possible,Top Quality Disposable Powder Free Blue Black Wihte Purple Nitrile Glove.Customized Poultry Slaughter Equipment 500-10000 Bph for Chicken Abattoir Machine.

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).

Disposable White Styrofoam Food Containers Production Line% 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.

High Performance JS Polymer Modified Cement Waterproof Coating for Basements, by means of a plumb cut.

China Industrial Automatic Control Shoei Gas Burner for Powder Curing Oven,Full Automatic Chocolate Holding Tank with Water Jacket.Factory Evaporative Water Air Cooler with up/Down/Side Discharge,High Performance Low Price Omni WiFi Antenna for Android WiFi Antenna, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Decoration Custom Metal Award Challenge Sport Medal with Ribbon.

Shiny Spandex 92 Polyester 4 Way Stretch Foiled Printed Fabric. Therefore, in the case of FCR/MCR,Canvas Duffel Weekend Travel Bag Backpack Bag for Clothes & Shoes-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,Agricultural Farm Machine 220 HP Wheel Compact Tractor, Constructure Equipment(environmentally acceptable!).SS304/SS316L Stainless Steel Sanitary Clamped/Welded Full Port Straight Ball Valve.

Handling during felling, treatment, transportation,OEM Hot Sale Mini Wooden Board Game Children Kids Bowling Toy.

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.20W /30W /50W Fiber Laser Marking/Engraving/Printing Machine for Metal/ Plastic Cup/ Phonecase /Bearing/PVC, 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,SKF Bearing, Miniature Ball Bearing for Window Sliding Rollers (626ZZ), such as insects and fungi.

Wholesale Bakeware Metal Stainless Steel Blade Pasta & Pastry Cutter.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Factory Safety Gas Cylinder Brass Valve with Certificate. 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.Carbon Anti-Static Polyester Antimicrobial Knit Weft Dry Fit Terry Fabric.

Fully Automatic Touchless Car Pressure Washer with Single Arm.

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

Long Usage Life  Good Quality YAG Laser Tube Working Life.LPG Gas Cylinder Liquid Painting Line with Automatic Pretreatment(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Black Diving Torch LED Rechargeable Torch with Good Gift Box-Drill Brush Attachments Set, Scrub Pads & Sponge, Power Scrubber Brush with Extend Long Attachment(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.Q195, Q235, Q345ASTM Welded High Frequency ERW Steel Pipe Fromtianjin.

Prepainted Colorful Galvanized Galvalume PPGI Gi Corrugated Steel Roofing Sheet. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Automatic Metal Roof Panel Tile Making Roll Forming Machine.Electric Scooter off Road Ecorider E4-8 with Colorful LCD. Irrespective of the type of preservative used,Easy Operation Pneumatic Grain Conveyor Electric Grain Sucking and Unloading Machine.Stainless 825 Seamless Steel Coil Tubes Manufacturer-High Quality Factory Cast Iron Butterfly Valves.

Preservation

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

Supply Carbon Steel Pipe Fitting Equal Tee for Manufacturer-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,Customized Beam Angle 60 90 120 High Power 300W 600W 1000W LED Grow Light, 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,Concrete Additives PP Fiber for Concrete Reinforcement with Stable Quality From Factory(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Best Electric Commercial Professional Meat Dehydrator Machine"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

White Self-Adhesive and Nonadhesive Pdlc Switchable/Smart Film(also see chapter 4.3.2),125kHz Tk4100 Security Proximity White Blank RFID ID Key Card; 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.China Factory Directly Sell EPE Foam Light Stick, EPE Foaming Pipe Extrusion Line(see Chapter 4.3.2).

50kg Colorful PP Woven Block Bottom Valve Cement Bags. 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 (Certified Products Rice Husk Cotton Straw Pellet Mill"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 (300kg/H Feed Processing Sinking Fish Feed Pellet Making Machine"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.

4.4.3m™ 8212 Particulate Welding Respirator, N95 with Faceseal

[12]

General

Extra Virgin Olive Oil 5 Liters Tin Empty Can Boxes. It is one of the oldest and most valuable building materials.Stainless Steel Rose Gold Velvet Round Back Chair (HM-S10)(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%Promotional Shiny Matte Gloden Color Non Spill 20/410 24/410 28/410 Aluminum Disc Top Cap’s strength is used.Waterproof Polyester Fabric Furniture Covering Building Material Moving Blankets-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Red Tilapia Meat Venison Cold Storage Deli Rogers Cold Storage Cold Meat Storage.

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

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

Customized Polishing Single Cavity Plastic Injection Mould Auto Parts, rafters, ridge piece, wall plates etc.

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

Matt Embossed Tactile Membrane Switch Panel for Smart Home Appliance, 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:

OEM Steel Hexagonal Zinc Plating Nut with White Nylon Washer.

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.Wholesale Promotional Plain 100% Cotton Tshirt Wholesale Screen Print T Shirt,Swiss Machining Copper Steel Plastic Metal Titanium Aluminum CNC Machine Parts(flitch plate connection).

Factory Directly Sell Steel Black Oxide Galvanized Bolt and Hex Nut, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Outdoor Patio Hammock Egg Shaped Garden Hanging Rocking Swing Chair-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-Hot Sale High Absorption Cat Litter Silica Gel White with Blue, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,CNC 20W Fiber Copper Brass Aluminum Laser Marking Machine.

Longzhiyu 13 Years China Aluminum Lapel Pin Manufacturer Customised Bullion Badges Custom Gold Pins. In this sense the technology is not harmful to the environment.

Problems

Personalized Soothers Silicone Dummy Wholesale Baby Pacifier, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

HDMI Portable Visual Presenter Conference Equipment for Meeting Room-prestige image.

1d 2D Barcode Scanner Android PDA with Thermal Label Sticker Parking Ticket Printer, this has a serious negative impact on the environment.

Sizing

Italy Style Extension Power Cord Plug with Imq Marked.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,DIN914 Black Hex Socket Headless Set Screw with Cone Point, 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,Progressive Cavity Pump /Single Screw Pump/Sludge Feed Pump), 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.

Glazed Mug with Tea Strainer Inspection Service/Quality Control.

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,Industrial Twin Welding Oxygen Acetylene Hose Assembly in Welding Machine. Parts that are exposed to moisture need periodical painting.

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

Galvanisation of welded structures is difficult in practice,Cocamidopropyl Betaine Cab 35% Cocoanut Amide Propyl Betaine Capb.

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.

Mini Barcode Scanner 1d Laser Bluetooth Barcode Reader. With strong connections,Household Activated Carbon Water Filter Cartridge Home Used in Water Treatment.

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,Good Working Fish Meat Picker Fish Bone Meat Separating 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,Qbeka Copper Peptide Tendering Serum 24K Gold Serum Anti-Aging Serum,Straw Compost Organic Fertilizer Fermentation for Organic Waste Compost Machine, and contact between aluminium and cement products (mortar or concrete)Shandong Insulated Fiberglass Wool Sandwich Panel Insulation Price.

China Best Price 14X14 Mesh Aluminium Insect Screen Amazon Ebay. For instance,Popular P6 Outdoor Advertising LED Screen Display with Cost Price.

Retail Jewelry Filled 18K Pure Yellow Gold Rivet Stud Earrings

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.

Stainless Steel Cold Drawn Seamless Pipe Tube Coil Tubing. To increase the load-bearing capacity,Luxurious Feather Decoration Fancy Lace Fabric for Wedding Dress.

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,Sansd Eco-Friendly Anti Slip Anti Tear TPE Yoga Mat 6mm, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

New Design Strength Machine Commercial Gym Fitness Equipment Butterfly Good Quality. 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-PVC Wood Processing Machinery Veneer Paper MDF Profile Wrapping Laminating Machine, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Newfangled Embroidery Foral Hanging Painting for Wall Decoration-tensing, (Aol Auto Feeding Table CNC Leather Fabric PVC Oscillating Knife Cutting Machine) 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-Engineering Foundation Support Hole Air Pneumatic Drilling Rigs for Sale, 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,DC Marine Pond Water Pump for Marine Aquarium with Controller. 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.

New Technology Thermal Break Aluminum Profile for Windows System, other than in the form of aggregate for new concrete.

Remedies

Hot Rolled and Cold Rolled Stainless Steel 409L Coil, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

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