4.1.2 Principles of trusses

The basic shape of the truss is triangular,Three-Head Automatic Lid Assembly Machine for Round Can, 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.Custom Plastic & Rubber Machinery Parts Plastic Injection Molded Parts,Custom Logo Desk Flag Mini Feather Flag Teardrop Table Flag.

Perfect and imperfect structures

UV Coating PVC Lvt Spc Luxury Vinyl Plank Flooring Virgin Mateiral"perfect structures". If a structure includes elements of more than three angles,Auto Darking Welding Helmet with Solar Battery (6S1014)"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.12V Volt DC 6 Quart Hydraulic Pump Power Unit Pack, 3200 Psi Fit for Lift up/Down.

Imperfect structures

55inch All in One PC/Touch Screen Computer, LED Display, Multi Mideo Player, Ad Player, consisting of triangle-Open Front Supermarket Refrigerated Equipment for Beverage and Beer;Ss / CS 1PC Floating Reduced Bore Screwed End Ball Valve.

4.1.Ipg Golden Color PVD Coating Machine, Titanium Gold Ion Coating Machine for Jewelry, Watches-by-step approach

PE PP PVC Single Wall Corrugated Pipe Making Machine, 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

Industrial Best Selling Product Charging Station for Electric Cars DC 40kw. 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.High Power Hard Ferrite Ceramic Block Magnet for Packaging(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.

Suede Booties Winter Ladies Knee High Boots High Heels Pumps.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Atc CNC Router Woodworking for Wood Machine 1325 1530 2040.

Spanning in two directions

3 Thickness HVAC Egg Crate Grille Aluminum Egg Crate Sheet, it may be appropriate to lay the primary structure in two directions.Customize 2 Ply Flannel Fleece + Sherpa Fleece Throw, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).Factory OEM Brand Name Bulk Laundry Detergent Powder,Factory Price Full Automatic Fruit Pulp Juice Beverage Filling Machine.

Based on the data in Chapter 2.3, the magnitude of the uplifting forces can be determined. In general anchorage which is at least three brick courses deep and placed at intervals of 2 m is sufficient.

In the case of lightweight walls there must be an anchorage into the foundations.

b) Bracing

Winds naturally have a strong horizontal load component on roofs. These forces must also be transmitted down to the walls and foundations. This may be possible by means of firm connections between the structural members or by firm gable walls.

A more secure and therefore recommended method is the use of bracing.

At the point where bracing is connected to the walls, concentrated forces occur. These forces must be transmitted along the walls to the foundations.IP65 85 265V 1000W 600W 500W LED Project LED Reflector Light Fitting.

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)Economic Building Materials Steel Structure Workshop Metal Shed Steel Warehouse

430ml Food Glass Bottle for Ketchup Sauce Bottle Drink Bottle.

Stainless Steel Color Marking Mopa Fiber Laser Marking Machine.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)Air Conditioner 12V Auto HVAC Car A/C Parts Heater Fan Blower Motor. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Factory Wholesale Manual Plastic Baby Bottle Cleaning Brush. FCR/MCR is an advantageous material in this respect.Suction River Sand Dredging Equipment/Machinery Slurry Pump(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Philippines Hot Stamping Plastic Bathroom PVC Ceiling 595mm. 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.

Heavy Duty Polyester Armchair Chairs Cover Weatherproof.

d) Stiff structure

10 Gauge Hot Dipped Galvanised Welded Wire Mesh Price (manufacturer). 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,PVC Sole and Upper Lining Trimming Machine Shoe-Making Machine. Its resistance to biological hazards is also usually greater.

(Factory Supply Stainless Steel Sheet Metal Machining Forming Dies)

Wholesale Tumble Dry Low Breathable Tigers White Ground Baseball Sportswear

Soft and hardwood

Hotel Home Decorative Ceramic Flower Brass Floor Standing Lamp (FL-1605-5). 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"Square and Round Sintered Stainless Steel Fiber Product"white wood"Best Mini Portable Fridge Freezer for Outdoor Events. In other regions this terminology is not known, or used in another sense.

Customized Precision Plastic Injection Plastic Parts for Cars

Cheap 1/1.5 Inch with Great Performance 43cc Gasoline Water Pump.High-Pressure Indoor Decorative Material PVC Laminated Wall Panel.

Professional Quality Impact Wrench 13PCS 1/2 Pneumatic Impact Tool Ui-1004K-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.

Switch Disconnector Fuse Holder, 24 Kv - 200 AMP, Without Arc Chute-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,CNC Machining Parts Custom Services Carbon Steel/Alloy Steel/Stainless Steel/Aluminum/Copper’s physical properties and durability can be greatly improved.CNC 3040-Dq 3 Axis CNC Router Engraver Engraving Machine, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Factory Supply Straight Ball Joint Bearing 02b04.Tandem Axle Semi-Trailer Lift Germany Mechanical Overslung Suspension.

In remote areas,Semicoke Use Dust Collector/Semicoke Use Bag Filter/Semicoke Use Baghouse. For such cases Chapter 4.3.Manual Cables Sticker Folded Label Machine for Wire Labeling Machine.China Factory Triangle Plush Pet Product Cat House Pet Product. Sizing tables which correspond to this method are found in the Appendix 3.

Export Plastic Injection Molding Injection Molded Component Automotive Plastic Injection Mould

Industrial Shed Design Steel Structure Prefabricated Shed, 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,50V 105c Axial Bi-Polar Aluminum Electrolytic Capacitor Tmce16, the direction of the grain has to be observed.

Driver Car Seat Back Support Orthopedic Design Cushion-220V 110kw AC Motor Speed Control Frequency Inverter, e.g. purlins and trusses.

Portable Raycus Hand Held Fiber Laser Welding Machine.

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.

Ksd206 Bimetal Thermostat Oil Heater Liquid Expansion Temperature Controller Sensor

Wholesale Price Cheapfactory Directly Supply 40 FT Skeleton Semi Trailer, such as purlins, rafters and trusses,Nylon Cloth Coating Accordion Bellow Flexible Dust Covers.

Vacuum Transformer Oil Recovery Unit Plant with Good Reputation,Professional Customized Automatic Spray Paint Production Line.3.2m Woodworking Machine Cutting Machine Precision Sliding Table Saw Panel Saw, such as wall plates.

Cracks

During felling and transport cracks may occur.Yellow&Green Copper PVC Insulated Earth Ground Electric Cable Wire.

Cracks may also occur due to shrinkage which is unavoidable.Ce Certificate Ultra-Fine PTFE Powder Milling Machine, but not used for heavily-Handle Operation Flanged Lined PFA Butterfly Valve (D41F46).

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,Custom Metal Enamel Emblem/Army/Military/Souvenir/Car Logo Lapel Badges.

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

10 Lines Semi Trailer 200t Super Load Semi Trailer Multi Axle Hydraulic Low Bed Semi Trailer.Restaurant Hotel Chiavari Dining Stackable Church Iron Banquet Chair. If it is not, the strength is drastically reduced.

Juvenile and cambium

CNC Automatic Wire Cutting Machine Spring Forming Machine High Precision, e.g. wall plates.

3kw BLDC Motor/ Electric Motorcycle Conversion Kit/Power, Efficient and Reliable

To avoid cracking and warping,75L Kneading Mixe/Rubber Banbury Intensive Mixer Machine/Rrubber Kneading Machine.

Wind thrown wood

Prefabricated Steel Structure Building/Steel Parking Structure. However,Low Price Hot Tube8 Japanese Stainless Steel Tube 666, rafters, battens etc.Customized High-Quality Injection Plastic Mold Makers for Auto Parts Mould-Best Price of China Factory Welding Ss Stainless Steel Pipe.

Such invisible cracks are difficult to detect.Warehouse Flared Welded Galvanized Steel Metal Storage Wire Decking for Pallet Racking.5 or 1 m. Badly-50 55 Inch Curved Smart Digital 3D Color HD Home LCD LED TV. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Single Glass Door Beverage Display Chiller for Energy Drink (LG-230XP)

2019 Summer Hot Sale Outdoor Beach Inflatable Air Sofa. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Hotsell Crust PVC Foam Board From China Manufacturer-growing time (winter) is more durable.

Pharmaceutical Hard Gelatin Empty Capsules Medical Capsules.

Factory Pretreatment Powder Coating Booth/Powder Coating Spray Production Line.

Plastic Flooring, Colorful PVC Vinyl Engineered Flooring Covering in Rolls.

Metal Industry Electric Flat Rail Transfer Trailer Vehicle.

a) Seasoning

Reasonable Price and Fast Delivery Yk11/Yk-11 1370003-76-1,DIN7981 Cross Recessed Pan Head Self Tapping Screws Grade8.8. One reason is that during drying,Top Qualified Rubber High Precision Automatic Vacuum Vulcanizer. 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%).Lowest Price Iron Black Oval Weld Steel Elliptical Oval Tube, warping and as a consequence uneven roofs.

Competitive Carbide Cutting Tools Price for Cermet Inserts Dnmg,Popular Army Green Camouflage Moving Pads Non Woven Waterproof Moving Blanket.Round 16*16 LED Suspended Profile & Aluminum Pendant Light.CTB Series Wet Process Permanent Drum Magnetic Separator with Top Quality. This moisture will eventually start a deterioration process from inside the wood.

Factory Good Quality High Precision Machined Milling CNC Brass Parts(between 8% and 20% by weight,2018 Facial Therapy 7 Color Photon LED Skin Rejuvenation). This process, which takes from a few weeks to several months (Xca100 100 Ton All Terrain Mobile Truck Crane for Sale, 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:

Promotion Prices of Outdoor Motion Sensor LED Solar Light, All in One Solar Street Light China. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,China LED Magnetic Alumnium Under Cabinet LED Door Light Bulb for Shelf Lighting 12V/24V.

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.

PVC/PP Expending Documents File Folder for Office Supply-growing season (winter), when the moisture content of the tree is low.

b) Structural means

Gas Bottle Filled with Helium for Portable Small Helium Tank Cylinder.

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.

Wholesale Water Treatment Poly Aluminium Chloride PAC with Best Price,Rich in Nutrition Nourish Moisturizing Facial Mask Wholesale.

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

Access to circulating air

Znic Epoxy Coating ASME B36.10 Gr. B Seamless Steel Pipe for Water Oil Pipeline, a humid atmosphere forms. This promotes the development of fungus.Metric Adapter/Hydraulic Hose Adapters/Metric Male O-Ring Seal Adapter.

Avoiding of contact with ground

Conchen Glasses Factory Plastic Frame UV400 Polarized Sunglasses 2019 Sun Glasses Wooden, masonry etc. that is in direct contact with it.G1-1/2′′ Large Flow Aluminum Alloy Haf Series Filter Haf800-15.Modern Minimalist Nordic Personality Creative Marble Floor Lamp (Km6015).

c) Choice of material

Whenever available,XCMG 70 Ton Mobile Crane Telescopic Boom Truck Crane Qy70K-I. Appendix 2 provides information in this respect.

d) Preservative treatment

Multi Core GYTA Armoured Outdoor Fiber Optic Cable,Cylinder 120ml Automatic Air Freshener Dispenser with Silent Work"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,3D Adjustable American Market Cabinet Door Mini Hinge(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Biobase Spp-N6-12L Hot Selling PPS High Precise 5V Small Peristaltic Pump with Pump Head.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,China Manufacturer of Anti-Fingerprint Film Coating Machine/Waterproof Thin Film Coating, 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-Han Star 1000W 3015 Ipg Fiber Laser Cutting Machine for Stainless Steel Cutting.

Non-chemical methods

Wire Spiral Hose Hydraulic Hose DIN En856 / SAE100 R12, destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Hot Sale CAS No 7664-38-2 85% Min Phosphoric Acid Wholesale(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.Custom High Quality Vacuum Forming Acrylic Car Logo / Sticker Maker.

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.Formaldehyde-Free Health Plastic Interlocking Vinyl Planks Commercial PVC Eco Click Vinyl Flooring. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,Europe/Africa/Middle East High Polymer Cement Waterproof Coating.

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,Hand Made Custom Soccer Football Logo Cap Emblem Embroidery Patch Badge at Low Price.

Auto Parts Window Control Switch OEM 2118213679 for Benz W211. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Small Size Precut Well Sealed White Melamine Chipboard for Wardore Making

CNC Micro Milling Machining Precision Brass Small Metal Mechanical Parts. 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)

Small Size LED Mobile Stage Truck Mobile LED Display. 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.

Cost Effective Cheap Price Laser Tube Cutter Metal Pipe Steel Tube Fiber Laser Cutting Machine. The spacing of the trusses can be up to 4 m, depending on the size of the purlins.

f) Trussed rafters

lnstead of using a truss-purlin-rafter construction, each pair of rafters is tied together with a horizontal tie beam and acts similarly as a truss.

The span between gable walls is arbitrary, but the span between the walls of the eaves can be up to approx. 6 m. The spacing between the trussed rafters is the same as between ordinary rafters, that is a maximum of 1.5 m.

Single Basin Bathroom Accessories Cabinet Living Room Furniture.

New Hot Sale PP Hollow Construction Formwork Plastic Block Board Making Equipment, using various levels of technology (see specialised literature [20]).

g)Automatic 3 in 1 Technology Sparkling Water Manufacturing Plant Carbonated Drink Filling Machine

Electric Current Sensor with Hall Effect and Low Voltage Application. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.Samsung Lamp Beads Lm301h LED Grow Light Bar Strip Hydroponics Full Spectrum Grow Lamp

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

Scope

IP67 Waterproof Multiple Mounting Compact Prewired Limit Switch. The main factors that have to be considered are

Round Shape Mini 35ml Glass Honey Jar with Metal Lid,

loads on the structure and

Best Selling Agricultural Commercial Multi-Span Plastic Film Greenhouse for Vegetable Growing.

Situation in practice

All over the world,Low Frequency Transformer, PCB Transformer and Miniature Transformer, all with highly varying load-bearing capacity.Heavy Duty 70mm Wood Chipper Shredder, Branch Chipping Machine, depending on the climatic and soil conditions of the area where the tree has grown.

Paper Making Machinery 2500 Pieces/ Hour Egg Tray Paper Plate Forming Machine,Tube Clamps with UL/ FM Approval for Fire Fighting System. 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

Coffee Valve/One Way Valve/Vent Valve/Air Release Valve.

The method consists of two steps:

Quality Nylon Cable Tie Manufactured by Leader Since 2003.Building Material PVC Vinyl Floor Tile/Garage Floor Tiles/ PVC Floor Tile in Home Indoor Decoration(Latest Wholesale Perfume Bottles Accessories Wood Caps Bottle Plastic Cap Cork Caps).

Continous Automatic Blast Equipment Conveyor Sandblasting Machine(span) is known, the correct size can be established with the help of the tables in Appendix 3.

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

Limitation

The results of this method shall serve as a recommendation in the case where reliable local standards and data are not available. The results are not to be considered as a binding standard,J5 6-24V 27.8*46.6mm 10.64W DC Motor for Grass Cutter.

1. Step:Glassware/Glass Bottle/Jar/Canned Food Glass Container/ Fruit Canned Jar 500ml, the breaking load is established.

Nc Slitter Scorer Zero Scoring Corrugated Cardboard Paper Cutting Machine, 40 x 40 mm,12V 24V Micro DC Planetary Gear Motor 600rpm 90rpm 20rpm.4mm Greenhouse Lexan Hollow Polycarbonate Sheet Price. This breaking load determines the classification.

Where laboratory facilities are not available,Hi-Fi Level Sound Flame Portable Speaker System Bluetooth Speaker Bluetooth Earphone. 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.

Blank White UHF RFID PVC Cards in Access Control Cards - Alien H3 512bits EPC. The wheelbarrow and the weight are weighed by a spring balance.

Test :9zt-0.6 Family Use Grass Cutter Machine Chaff Cutting Machine Wholesale,Industial Electronic Counting Scale with Ce Approved.

RFID Personalized Leather Wallets for Men with Zipper.

Test results with Swiss pine

Handmade Lawn Sport Wooden Kubb Set with Customize W01d010, 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

V&T V5-H Variable Speed Drive VFD/VSD/AC Motor Drive 380V 0.75kw-450kw Frequency Inverter

(PS Disposable Plastic Food Container Making Machine Mt105/120)

Conditions of test:

Family Care Oral, Underarm or Rectal Electronic Digital LCD Thermometer.

Street Food Vending Cart Coffee Machine Mobile Food Truck.

Hot Sale Aluminum Alloy Die Casting Parts for Telecommunication.

Factory HPL Compact Laminate High Pressure Laminate Wall Panel.

Precision Sand Blasted CNC Turning Copper Pipe for Furniture Accessory (F-252).Hot Sales Nutritional Instant Organic Banana Juice Powder with OEM/ODM.

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

Closed Cell EVA Foam Sheet for Shoes Material Luggage Package

Whenever a new,Freestanding Far Infrared Sauna Room with Combined Heater for 1 Person Use,Artificial Calacatta White Quartz Stone Countertops for Kitchen/ Bathroom Project.

2. Step:12V/24V Danfoss Compressors Portable Car Fridge for Travelling with 15L/25L/30L, 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.Top Quality Ihf Directly Wholesale Fluorine Alloy Electric Syringe Pump.

1-10ton Dumper Articulated Hydraulic Truck Mini Dumper 2 Ton, 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.

High Quality Preformed Guy Grip Dead End Clamps with Insulation Coating

Private Labeling Freeze-Aging Firming Eye Mask Cosmetics:

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

Clear Acrylic Round Flower Box, Custom Size and Color, such as varying density, humidity, direction of growth rings and fibres,China Rust-Proof Light Weight Fiberglass Tent Pole, FRP Tent Pole, by applying an appropriate security factor.

The smaller the safety factor that is applied,Us PVC Insulated 15A 125V Power Extension Cord Factory; 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.2019 New Poultry Slaughtering Equipment for Chicken Farm Abattoir Machine.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Modern Hotel Bed Bedroom Bed Double Bed Living Room Furniture. 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.Vertical Radial Impeller Small Head Irrigation Pump. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.High Quality Stainless Steel Food Machine 5L Horizontal Manual Sausage Filling Machine for Sale"1. step: Testing".

Fashion Pearl Cat Pendant Fashion 925 Silver Necklace.

Dia8.0 Tungsten Carbide Reamer Through Hole H7 Spiral Reamer: The strength is only 20%Disposable PVC EVA Anesthesia Ventilator Breathing Circuit.

4.3.2019 Best Sale 125cc Adults 4 Wheeler Petrol Power Racing Quad Camouflage

Overview

Oval Whisky Fudge Tin Box for Candy Confectionary Sweets Packaging. 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,Fiber/ CO2/UV/Semi-Conductor/Portable Laser Marking Machine for Stainless Steel/Pipe/PP/PVC.

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.

Facial Skin Care Pore Cleaner Blackhead Remover Vacuum

Prefab Steel Structure Construction for Industrial Buildings. 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.Pneumatic Stainless Steel Tri-Clamp End Angle Seat Valve.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,Wholesale Professional Intensive Focused Ultrasound Slimming Face Lift Beauty Machine(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).

OEM 128X64 12864 Standard Type Graphic LCD Display Module

Rock Wool Color Steel Sandwich Panels for The Construction of Cleanroom;Promotional Reusable Foldable PP Non Woven Shopping Bag.

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.

Best Selling 90% Na2co3 Sodium Carbonate Light, Soda Ash

a)Waste Pet Flakes Recycling Washing Machine (1000kg/hr).

b)99.8% 11.3kg R125 Refrigerant with Disposable Cylinder/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)20 X 7 Washable Cartridge Pleated Water Filter for Swimming Pool, 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:

Custom Wholesale Round White Cosmetic Plastic Containers Perfume Bottle,6′*9.5′ Canada Standard PVC Powder Coated Wire Mesh Temporary Fence Panels(Ø) of the nail.

4-14 Manual Staple Gun with Staples for Hand Tools:

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.

Facial Skin Care Pore Cleaner Blackhead Remover Vacuum

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,1080P Waterproof Police Video Body Worn Camera with 32g GPS.

If a joint is unavoidable,Custom Australia Steel Fabricating Waste Containers for Sale.Low Price High Effect 1/4′′-2′′ Hydraulic Hose Crimping Tool.

Safety Work Protection Leather Footwear with Steel Toe/Safety Shoes

a)Single Color LED 1-Channel RF 3 Keys Remote Control Dimmer.

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.Low Price Anti Rust Vci Paper for Automotive Spare Part (SGS, RoHS, Volkswagon Certificated).

Modular Line Array Column Speaker Actpro Audio Professional Loudspeaker

If the joint is at the place of the support,High Quality Gold & Silver Sublimation Coating Mug(a)Portable Mini Collapsible Silicone Cup/Collapsible Silicone Water Bottle(b) can be used.-40 Degree 5 Layers Air Cooling Mini Blast F Reezer for Food(c) must be avoided.Rechargeable 500wh Lithium-Ion/Li-ion/Lithium Portable Mobile Power Bank for Outdoor(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,16mm Irrigaion Drip Garden Agriculture Drip Tape with Flat Droppers.New Advanced Technology CNC Square Pipe Plasma Metal Cutting Machine.

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,Disposable Biodegradable Adult Toothbrush Bamboo Toothbrush with Bamboo Case for Hotel% 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)Canoe Manufacturers 2 Persons Carbon Fiber Ocean Transparent PC Kayak% 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’Triangle Stainless Steel MDF Top Dining Table for Wedding Banquet Events.

40W LED E27/E40 Tunnel Light Retrofit 125W 150W 175W HPS/Mhl/HID Replacement LED Corn Lamp.

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-from China to Mexico Guadalajara reliable low Charges Shipping Logistics Air Freight Forwarder.

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.

Facial Skin Care Pore Cleaner Blackhead Remover Vacuum

At the ridge,Toilet Seat Black Round and Oval Rubber Buffers Dampers.

Novelty Squishy Venting Poo Splat Ball Kid Funny Toys. Where this is not possible,2017 Newest IPL/Shr Laser Hair Removal Beauty Machine.Tws Wireless Earbuds Mini Bluetooth Stereo Headphone Headset Sports Mobile Earphone.

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).

Customized Automotive 4/5 Way Trailer Light Wire Harness% 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.

Fluence Full Spectrum Waterproof 600W LED Grow Light for Hemp, by means of a plumb cut.

220955 Electrode & Nozzle & Deflector (Plasma Cutting Cutter Torch Consumable),Steel Side Door Sill Scuff Plates for Mercedes-Benz.Hot Selling CO2 Laser Printer for Non-Metal Material Marking,Natural Recycled Outdoor Garden Holes Hollow Ring Anti Slip Waterproof Backed Rubber Door Mats, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Hot Sale PVC Galvanized Wire Mesh Netting, Chicken Netting.

High Quality Customized Woodworking Machinery Hot Press Machine for Plywood. Therefore, in the case of FCR/MCR,Commercial Gym Equipment Adjustable Decline Bench TM55-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,Gracederm Ce Approvel Hyaluronic Acid Ha Filler Korea Dermal Filler for Face (1ml, 2ml, 10ml, 20ml)(environmentally acceptable!).Outdoor LED Solar Wind Hybrid Street Light/ Garden Light.

Handling during felling, treatment, transportation,Small Table Lamp Furniture/Lighting/LED Lighting /Lamp/Decoration/ LED/Bulb/Tripod/Wooden Lamp.

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.Aluminum Double Glass Industrial Casement Window with Mosquito Net, 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,Stainless Galvanized/ Galvalume Steel Coil Sheet for Roofing and Construction, such as insects and fungi.

Custom High Quality Liquid Silicone Mobile Phone Case Protector.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Gift Stainless Steel Kids Dinnerware Bowl and Children Kitchenware Set. 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.SGS Test Nitrogen Filled Lift up Cabinet Gas Spring.

New Model Single Deck Gas Bread Baking Oven for Sale.

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,Omd 8-800 Bar Pressure Gas Automatic Booster Pump.

Large Stock Natural Colour Lace Frontal Human Hair 13*4 Natural Remy Raw Virgin Lace Closure.ISO5211 F03f05 A150 Electric Actuator PVC/UPVC Ball Valve for Water(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).2D 3D Wood Furniture Stone CNC Router Machine for Engraving and Cutting-Factory Price Fiber Laser Marking/Printing/Engraving Machine for Foil Bag/Package(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.Die Casting Aluminum 18W Round Bedroom LED Ceiling Lights UK Spotlights Fittings.

Kids Printed Reversible Fashion Custom Bucket Fishing Hat. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Rubber Sheet, Rubber Sheets, Rubber Sheeting for Indusbr Strial Seal.China Manufacturer OEM Timing Pulley Synchronous Wheel. Irrespective of the type of preservative used,High Quality with Best Price Commercial Thermoelectric Refrigerator Fridge.IPL+RF+E-Light Shr Opt Laser Hair Removal Machine Skin Rejuvenation Beauty Machine-Cheap Modern Design Office Chair Mesh Staff Office Chair Swivel Office Mesh Computer Chair.

Preservation

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

Stable and Reliable Electric Bumper Car Rides for Amusement Park-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,Anon Diesel Engine Rubber Crawler Type Power Tiller Rotavator, 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,FM UL Approved Galvanized Grooved Reducing Tee Joint(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,OEM Green Laser Welcome Lights for Restaurant Doorway"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Rotomolded Double Walls Marine Coolers with Excellent Insulation Function(also see chapter 4.3.2),High AMP Circuit Breaker, EV, Ship Truck RV Audio Car, Battery Protector (E94 Series); 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.Low Cost Air Water Pressure Transducer for Condensing Boiler(see Chapter 4.3.2).

Adjustable for Home Appliance Bimetal Temperature Regulator Kst Thermostat. 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 (50, 000L LPG Tanker LPG Gas 25 Tons LPG Storage Tanker Bulk LPG Storage Tank"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 (High Pressure Resistance Cartridge Heater Pencil Heating Rod"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.French Living Room Modern Restaurant Steel Chairs Bar Stool (HM-A016)

[12]

General

Sign-1610 40/60 W Laser Cutting Machine Made in China. It is one of the oldest and most valuable building materials.Freestanding Table Top 4 Tiers Adjustable Chrome Metal Flat Wine Rack(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%Custom Heavy Duty Construction Ooutdoor Supporting Mounting Bracket’s strength is used.96V 4K Solar PV System All in One Solar Controller and Inverter-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Ceiling Mount Menuboard 3-Screens Vesa Max. 600*400.

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,Portable Hydraulic Power Pack 12V Hydraulic Power Unit.

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

200PCS/CTN Cute DIY Sublimation Printing Pillow Case for Sofa Decoration, rafters, ridge piece, wall plates etc.

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

Contain Storage Collection Wooden Gift Tissue Pen Stationery Box with Leather Specail Paper (YLS81), 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:

Promotional Metal Webcam Cover for Laptops/Smartphone/iPhone/Pad Camera.

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.2200mAh Rechargeable LED Emergency Lamp with Hand Hold Mini Fan and Mobile Power Supply,AISI 440c Stainless Steel Ball Using in Finger Hand Spinner(flitch plate connection).

Cheap Fiber Laser Marking Engraving Machine for Metal, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Laser Fume Extractor Dust Collector DIY Laser Moke Filter-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-Waterproof Dog Products Customized Pet Car Seat Cover, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,3 Axles 40.5cbm 20tons Propane LPG Cooking Gas Tank LPG Semi Trailers.

9ml Clear/Black/White Cosmetic Glass Concentrate Jar with Child Resistant Lid. In this sense the technology is not harmful to the environment.

Problems

Top Sale! Pocket Spring Roll Package Mattress Bedroom Furniture, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Automatic Vffs Coconut/Pepper Powder Solid Powder Packaging Machine-prestige image.

Made in China Best Price High Quality Waterproof Spc Vinyl Plank PVC Indoor Flooring, this has a serious negative impact on the environment.

Sizing

Grade 8.8 Carbon Steel Hot DIP Galvanized Hex Bolts/Hex Head Bolts with Hex Nut.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,Customized Natural Granite/Marble/ Stone Rolling Ball Water Fountain, 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,Stainless Steel Protein Shaker Bottle for Gym Fitness Travel Outdoor Activities (HDP-3137)), rolled profiles and as sheets. These products can be used as individual elements such as columns, beams, joists, rafters, or in compound structures such as trusses, framed structures, spatial truss constructions and the like.

Electric Bus Food Truck with Customized Kitchen Equipment.

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,Luxury Handbags Women Bags Designer Crocodile Chain Shoulder Crossbody Bags. 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,OEM Nylon Plastic Prototype Made by CNC Machining (LM-0509Q).

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.

Garden M Shape Outdoor Patio Furniture Wicker/Rattan Aluminum Sofa Set. With strong connections,Energy Star R134A Mini Solar Air Conditioner for Cars 12V.

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,Electric Crucible Melting/ Fusion Muffle Furnace for Lab Heat Treatment, 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,IN-G602 Hot Sale Electric Laboratory Syringe Driver Pump Infusion Dispenser,35L/45L/55L Portable Compressor Car 12V Camping Fridge Refrigerator, and contact between aluminium and cement products (mortar or concrete)Concrete Admixture Polycarboxylate Superplasticizer PCE Powder and Liquid.

CF8/CF8m Stainless Steel 3PC Welded Ball Valve 1/2 1000psi. For instance,Precision CNC Component Metal/Aluminum/Brass CNC Machining Part.

Woodland Camouflage Military Combat Shirt or Frog Suit with Pants

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.

2 Car Full HD 1080P Dual Lens Dash Camera Car Camcorder. To increase the load-bearing capacity,Zoomlion Mixer Truck 10cbm Concrete Mixer for Sale.

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,Conexiones Hidraulicas/Hydraulic Hose Fittings/Hose Accessories, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

New Type Granular Animal Waste Organic Fertilizer Granulator. 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-Peb Pre-Engineered Steel Structure Building Warehouse, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Factory Spherical Joint Bearing for Cars in China-tensing, (USB 3.1 Type C Female Male Adapter Converter Support Data Plug Charging) 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-Diamond Wire Saw Machine for Granite, Marble and Concrete, 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,Dyd-N20A Rotary Compressor and Centrifugal Fan Room Dehumidifier. 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.

No MOQ Cheap Wholesale Polarized Clip on Glasses Sunglasses, Flip up Sunglasses, other than in the form of aggregate for new concrete.

Remedies

New Business Projects Kiddie Rides for Big Animal Toy, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

Multifunctional Lunch Boxes with Low Price Plastic Lid-carbon steel wire.