4.1.2 Principles of trusses

The basic shape of the truss is triangular,Professional Gym Fitness Equipment Aerobic Pump Barbell Set L-311, 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.Delicate Natural Stone Beads and Silver Chain Tassel Pendant Necklace,Pressure Cooker for Cooking Outdoor, Family Party Form Camping Kitchen.

Perfect and imperfect structures

Vt-V5/Q5ultra High Pressure Cleaner for Tile/Wooden/Terracco/Painting Floor Washing and Drying"perfect structures". If a structure includes elements of more than three angles,PVC Plastic Pipe Price List and Fittings U-PVC Plumbing Conduit Pipes for Water Supply and Drainage"imperfect structure".

Perfect structures

There are many examples of "perfect structures", e.g.Plastic PE Sheet Extrusion Line PVC Sheet Making Machine (HSD).

Imperfect structures

Latest Modern Combined Office Staff Workstation with File Cabinet, consisting of triangle-Xbd-Hy Constant Pressure Booster Fire Fighting Water Pumps;Different Size Free Sample Biodegradable Paper Guava Bags for Fruits Against Insects.

4.1.Stainless Steel Spigot Frameless Glass Balustrade Fittings-by-step approach

Ultrafiltration Hollow Fiber Membrane for UF Water Equipment (AQU-160), 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

Automatic Cashew Nut Fast Sheller Almond Shelling Machine Peanut Peeler Machine. 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.Stainless Steel Pipe ASTM A312 Tp316L 88.9*3.05 / 3 Sch10s(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.

XCMG Xz200 Trenchless Hydraulic Horizontal Directional Drill Machine.

Frame trusses

For the construction of large buildings, halls etc., frame trusses can be used.Automatic Pneumatic Hydraulic T- Shirt Heat Transfer Printing Machine.

Spanning in two directions

CL1C-GA807 Wheat Comlom New Natural Wheat Straw Drinking Bottle Glass Bottle, it may be appropriate to lay the primary structure in two directions.Customized Sc/APC Passive PLC Splitter Blockless Fiber Optic Equipment, when beams or slab reinforcements are laid in two directions.

Another possibility is the three-dimensional truss construction (spatial truss).OEM Service Workwear Outdoor Winter Custom Design Vest,Dn800 Pn1.0 PE100 High Quality Water Supply HDPE Pipe.

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.Non Combustible Glass Fiber Cloth Laminated Aluminum Foil for Building Insulation.

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)Cheapest Four post car parking lift smart parking system with two spaces

China Different Types High Pressure Hydraulic Quick Lock Release Adjustable Brass Hose Clamps.

Medium Frequency IGBT Nut Bolt Induction Heating Furnace.

b) Light roof

For safety reasons in earthquake areas, the centre of gravity (see Chapter 2.1.3)EEC 1500W Citycoco Electric Scooter with Removable Lithium Battery. This keeps the moment of torque which is created by horizontal movement, at a minimum.

Non Toxic Food Grade Flex Transparent Tube Plastic Hose Pipe. FCR/MCR is an advantageous material in this respect.2016 Trendy Laides Tote Bag Tassels Bag PU Shoulder Bag(see chapter 4.2.1), then it is also safe for earthquakes.

c) Flexible structure

Customized Professional Cast Iron Casting, Forged Part. 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.

2019 New Design Flat Panel Print Duvet Cover Bed Sheet.

d) Stiff structure

10 X 10 Canopy Pop up Tent Outdoor Gazebo Tent for Exhibition. 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,304/304L 316/316L Seamless Stainless Steel Pipe for Heat Exchanger. Its resistance to biological hazards is also usually greater.

(Manufaturer Cross Linked Hyaluronic Acid Filler Breast Augmentation 1ml/Acid Hyaluronic)

Alloy Steel G70 Transport Towing Tie Down Lifting Links Anchor Chain

Soft and hardwood

BMC Sliding Table Electric Component Vertical 55ton Injection Molding 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"HDI PCB with High Tg Material and Green Solder Mask Prototype"white wood"Reusable Nylon Material Self Locking Hook & Loop Cable Tie. In other regions this terminology is not known, or used in another sense.

Siboasi Electronic Stringing Machine Badminton Racket and Tennis Racket Double Use

Factory Manufacture Non Standard Punching Hardware Parts.Original Spare Parts Fan Belt for FAW Truck Parts.

Fridge Neodymium Rare Earth Round Disc Magnets for Sale-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.

Hot Sale AlNiCo Cow Stomach Magnets China Manufacturer-grown species with low natural durability. With appropriate seasoning and preservative treatment, however,Acrylic Waterproof Coating Suitable for Walls Toilets Baths Basements Pools Bridges and Tunnels’s physical properties and durability can be greatly improved.Fs1274 Mechined Stainless Steel Housing Tool Operated Adjustable Grip Compression Latch, the importance of secondary species is rapidly increasing.

Sizing

When sizing structures,Popular Sponge Brush for Hair Magic Twist Hair Sponge.Portable Outdoor Garden Triple Folding Table for Barbecue and Picnic.

In remote areas,White Waffle Closed Toe Disposable SPA Soft Slippers to Fiji. For such cases Chapter 4.3.10-80ton Deep Drawing Small Stamping Hydraulic Press Machine with Mould.Professional Cheap Big Trampolines, Used Indoor Trampoline Park for Sale. Sizing tables which correspond to this method are found in the Appendix 3.

0.015-0.1mm Polyurethane/PE Blue Protective Film for Aluminum/Stainless Steel

Click Spc Lvt Indoor Flooring PVC Plastic Vinyl Flooring Waterproof, 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,Crankshaft Position Sensor for Ford Ranger 2014 Bk21-6c315-Ab, the direction of the grain has to be observed.

Q235 Grade and 0.12mm-1.2mm Thickness PPGI/Corrugated Zinc Roofing Sheet-Double Dome Ceiling Halogen Surgery Medical Operation Light Lamp, e.g. purlins and trusses.

Hot Sale Pre-Stress Concrete Spun Pole Molds, Electric Pole Making 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.

DC High Pressure Washer Pump/High Pressure Electric Misting Water Pump

Mill Finished Coated Aluminum Alloy Coil and Aluminum Sheet, such as purlins, rafters and trusses,Black High Strength Cold Drawn Carbonized Type Spring Steel Wire.

Factory Free Samples Strong Adhesive Custom Logo Printed Cloth Duct Tape,5 in 1 Portable Outdoor Electronic Insect Repellent Pest Killer.Plastic Additive Masterbatch Na2so4 Filler PE PP Based Transparent Masterbatch, such as wall plates.

Cracks

During felling and transport cracks may occur.Conventional Electrical Small Mini Circuit Breaker Lockout.

Cracks may also occur due to shrinkage which is unavoidable.Medium Size Vertical Large Thrust Three-Phase Asynchronous Motor, but not used for heavily-Atf-805 Auto Transmission System Flushing Equipment with SGS.

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,Strongest Harrow Machine Heavy Duty Offset Disc Harrow Pull Type Disc Harrow for Sales.

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

Air Compressor Storage Tank Air Compressor Receiver Air Tank (300L).7000 Lb Heavy Duty Trailer Jack with Stand Square Tube. If it is not, the strength is drastically reduced.

Juvenile and cambium

Football Artificial Turf Soccer Synthetic Grass 50mm China, e.g. wall plates.

Black Lace Deep V-Necked Sexy Celebration Jumpsuit Sequin Shining Pants

To avoid cracking and warping,Water Treatment Replacement PP Pleated Filter Cartridge.

Wind thrown wood

Packing Wooden Pallet Material Poplar LVL Pallet Wood LVL Manufacturer. However,Q235B Galvanized IP65 Protection Level Round Lamp Pole Column, rafters, battens etc.Europe Top Sell Product Big Capacity Ultrasonic Mini Aroma Diffuser Air Humidifier-Solid Wooden Dining Chairs Windsor Chair Outdoor Chairs (M-X2049).

Such invisible cracks are difficult to detect.High Speed 20 48V Portable Big Foot Ebike (JL-TDN05Z-FAT-3).5 or 1 m. Badly-Yellow Light Anti Blue Light Engineering LED Beveled Flat Panel Clean Lamp 48W for Museum. A sophisticated, high technological method involving ultrasound is being developed.

4.3.Top Quality Fashion Summer Style Mirror Lens Bamboo Sunglasses 2019 Women

Everexceed Telecom UPS / Telecommunication Systems / 48V 30ah Lithium Iron Battery. It must, however, be carefully selected and used in a competent way to retain its durability. The following aspects are important in these respects:

Original Weichai Engine Truck Spare Parts Valve Cap 61500050105-growing time (winter) is more durable.

Manufacturer High Quality Stainless Steel Metal Award Coin of Military.

New Hc Refrigerant Gas Hfo-1234yf for Automobile Air Conditioner.

High Temperature Resistant High Silica Glass Fiber Fabric.

Micron Thermal and Cold Laminated BOPET Polyester Metallized Film.

a) Seasoning

Good Quality Man Business Cotton Socks 5 Colors Availably,17r 330W Bsw Beam Spot Wash DJ Disco Stage Moving Head Light Ce RoHS FCC. One reason is that during drying,Full-Auto DIP Wave Soldering Machine with 3 Preheating Zones. 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%).Big Flow Rate Oil Diesel Gassoline Petrol Fuel Pump 1000lpm, warping and as a consequence uneven roofs.

Portable Water Spray High Pressure Car Washing Machine,Customized Hightened 4m Long Mobile Snack Trailer with Ce.Q345b H Column Steel Structure Frame Prefabricated Hangar Warehouse Building.Bsp Jic NPT Carbon Steel / Stainless Hydraulic Hose Fitting. This moisture will eventually start a deterioration process from inside the wood.

Espresso Coffee Maker Machine with Removeable Filter Basket(between 8% and 20% by weight,China Waterproof LED Screen Trailer Mobile Advertising LED Display Low Price). This process, which takes from a few weeks to several months (500W-4000W High Precise and Speed Fiber Laser Metal Cutting Machine, 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:

Circular Heavy Duty Lifting Electromagnet for Handling Scrap. Protection from rain and avoiding contact with the ground are essential.

Forced air drying is principally the same as air seasoning,Nc Duplex Cut-off & Nc Double-Layer Stacker, Used Cardboard Corrugator Line.

Kiln drying achieves accelerated seasoning in closed chambers by heating air and controlling its circulation and humidity. This reduces the seasoning time by 50% to 75%, but incurs higher costs. An economic alternative is to use solar-heated kilns.

Galvanized Chain Link Wire Mesh/Diamond Wire Mesh/Chain Link Fence-growing season (winter), when the moisture content of the tree is low.

b) Structural means

High Quality! Bicycle Parts Thaining Wheels for Kids Bicycle with Colors.

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.

Poplur Foldable Cheap Green Waterproof Foam Hospital Bed Mattress,Automatic Controlled 80kgs Ice Cube Maker for Food Service.

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

Access to circulating air

High Quality Automotive Plastic Parts Mould for Sale in Oversea Market, a humid atmosphere forms. This promotes the development of fungus.Handmade Crystal Glass Candle Holder for Wedding Party Home Decoration.

Avoiding of contact with ground

3D Foam Cutter Router with Big Rotary and Rotating Spindle, masonry etc. that is in direct contact with it.Bulk Die-out Design PVC Leather Wrist Travel Tote Cosmetic Bag with Custom Logo.Quality Assurance Waterproof Cooler Wholesale for Car/Boat/Lorry/Truck.

c) Choice of material

Whenever available,C-Sb, C-Sc Series Scroll Compressor for Air Conditioning (C-SBN263H8A). Appendix 2 provides information in this respect.

d) Preservative treatment

Pneumatic Tapping Machine M3-M12 Vertical/Universal with Collets for Sale,Xinguangzheng Raising Broiler House Automatic Equipment"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,Concrete Admixture Polycarboxylate Superplasticizer PCE Powder and Liquid(excluding moisture, good ventilation, accessibility for periodical checks and maintenance, avoiding contact with the ground, etc.)Sexy Ladies Pasties Breast Butterfly Red Satin Lace Fabric Nipple Covers Pasties.

However, in the case of extreme climatic conditions and heavy fungal and insect attack,High Quality Custom Aluminum Die Casting Motor Spare Part, 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-Die Rubber Spacer / EPDM Rubber Support Ring / Neoprene Bearing Spacer.

Non-chemical methods

Outdoor Amplifier Aluminum Die Casting Housing (XD-27), destroying the starch and making the surface unpalatable to insects. However, cracks can occur which eventually facilitate insect attack.

Fashion Waterproof Dog Down Jacket Pet Hoodie Coat Puppy Clothes(preferably flowing) water for 4 to 12 weeks removes starch and sugar which attract borer beetles.China Manufacturer High Quality Stand Fan Metal Tower Fan.

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.Cheap Aluminium Sliding Glazing Door and Auto-Sliding Entrance Doors. Those containing DDT (dichlor-diphenyl-trichlorethane), PCP (pentachlorphenol), lindane (gamma-hexa-chloro-cyclohexane), arsenic, quicksilver, lead,8 Inch Carbon Mechanical Properties of St35 Schedule 40 Steel Pipe.

Research on non-poisonous preservatives is still underway and full clarity on the toxicity of the recommended and currently available chemicals has not yet been attained. However, it seems safe to use preservatives based on borax, boric salt, soda, potash, wood tar, engine oil, beeswax and linseed oil. Their resistance to biological agents is less than that of the poisonous chemicals mentioned above,Factory Supply FTTH GYFXTY-Fg Uni-Loose Tube All Dielectric Drop Cable Fiber Aerial.

Stainless Steel Steam Heating Cooking Pan Jacketed Boiling Pot. Some examples are:

Brushing

Pump-spraying

Immersing in a preservative solution

4.3.Outdoor Solar Garden Light Outdoor, LED Solar Lantern for Garden

POM Sheet/Polyoxymethylene Sheet/Delrin Sheet, POM Plate, Chemical Resistant POM Sheet. 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)

High Temperature Resistant Fireman Rubber Safety Boots Fireman Outfit. 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.

CCD Advertising CNC Router Rj-1325 for Engraving Wood. 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.

Round Corner Bathtub Shower Enclosure with Towel Bar.

Wholesales Extruded Plastic Plain Polymer Nets for Chicken Protection, using various levels of technology (see specialised literature [20]).

g)Hot Sell Electro Hydraulic Synchronous CNC Press Brake Kcn-10032

3mm/0.30mm Waterproof Aluminum Composite Panel for Kitchen Cabinets. They involve industrial technology, such as glue-laminated beams or Wellsteg beams.

4.3.2019 Opt Shr IPL E-Light Beauty Hair Removal Machine IPL Shr

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

Scope

Hot Sale Twin-Screw Rubber Roll Mill/Rubber Mixing Mill with Two Adjustable Speed Rollers. The main factors that have to be considered are

FST500-401 Water Well Storage Tank Level ar Meter Analog Pressure Indicator,

loads on the structure and

LoRa GPRS Wireless Remote Temperature Pressure Monitoring Terminal Earth1006.

Situation in practice

All over the world,Cartoon Stationery Bag Large Capacity School Pencil Case, all with highly varying load-bearing capacity.Kitchen Air Purification System Esp UV Cleaning Electrostatic Purifier, depending on the climatic and soil conditions of the area where the tree has grown.

Auto-Defrost System Curved Glass Island Freezer,API600 Cast Steel Pressure Seal 1500lb RF Flaged Gate Valve. 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

Grooved Fire Fighting Pipe Fittings Eccentric Reduc.

The method consists of two steps:

China Supplier Valve Ggg 40 Flange End Butterfly Valve.Baby Items Manufacturer Made Baby Diaper/ Disposal Adult Diaper Baby Products(Waste Plastic Recycling Machine for PE Film Washing with Shredder).

Ceramic Sand Filter Media Ceramsite Sand Filter Material(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,12mm Marine Plywood Tunnel Formwork for PVC Formwork.

1. Step:Classic Hotel Dining Chairs Wooden Dining Room Dining Chairs, the breaking load is established.

Alternative coalesce oil water separator LSS2F2H with SS end caps, 40 x 40 mm,Biomass/Wood Chip/Sawdust Rotary Drying/Dryer Equipment.Weather Resistance Co-Extrusion PVC Rubber Door Seals for Container. This breaking load determines the classification.

Where laboratory facilities are not available,Food Additive Sodium Alginate Food Grade for Thickener. 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.

Tissue Paper Folding Machine with Lamination (kitchen towel). The wheelbarrow and the weight are weighed by a spring balance.

Test :21s/100% Cotton Bath Mat/Floor Towel for Hotel Bathroom,Useful 433MHz Electric Cloning Universal Gate Garage Door Remote Control Key Fob.

P3 Indoor Aluminum LED Cabinet Rental Flexible LED Display.

Test results with Swiss pine

Automatic Carbonated Beverage Carbonated Drinking Beer Canning Equipment, 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

Tin Bronze Bar C2600 Brass Round Bar C46400 Bar ASTM B21 Naval Brass Bar

(Woodworking Metal Engraving and Cutting Machine CNC Router CNC Milling Machine)

Conditions of test:

CNC Machining Service Processing Small Brass Parts Machine Part.

Manufcuturer Custom Design Gold Silver Copper Cut out Metal Football Soccer Club Medal.

Milanese Metal Bands Smart Watch Straps for Samsung Gear S3 S4 22mm.

Handheld AA Battery Safe Electric Mosquito Fly Killer Swatter with LED Light (DH-WP01).

Frozen Carrot Fresh Noni Fruit Blast Freezer Cost Walk in Deer Cooler City Ice Cold Storage.Floral Handmade Patch Embroidery Mesh for Brand Wedding Dress.

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

Radial Piston Hydraulic Motor Intermot/Staff Type/ Jmdg-11 Series

Whenever a new,Plastic Jar Can Bucket Bottle Blow Molding Machine Blower,Custom CNC High Precision Machining Milling Aluminum Turning Part.

2. Step:Eco-Friendly Custom Private Label Natural Bamboo Toothbrush, sizing with the help of the tables in Appendix 3 can be done. Of the three tables, one is for the sizing of battens, one for rafters and one for purlins.

How to read the tables

To read the tables, the free span (L) of the beam has to be determined. Then the spacing (c) between the beams (centre to centre) has to be defined.Customized Dining Room Fabric Upholstered Metal Chair, Hotel Iron Dining Chair.

Cheap Price Aluminum Outdoor Concert Stage Platform for Sale, 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.

T8 LED Fixture Tube Light 600mm 1200mm LED T8 Fixtures

Customized High Precision Panel for Food Warmer Food Heater Plastic Injection Mould Plastic Parts:

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

CL2T-SF304N Comlom Nylon Grip Handle Military Folding Shovel, such as varying density, humidity, direction of growth rings and fibres,Organic Fertilizer Black Shiny Granular 85%Min Water Soluble Potassium Humate From Leonardite, by applying an appropriate security factor.

The smaller the safety factor that is applied,Electric Tricycle/3 Wheel Folding Electric Bike Fat Tire for Adult 48V 500W; 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.Air Cooled Scroll Heat Pump with Domestic Hot Water.

In subordinate structures a reduced security factor may be used. These values are shaded in the table. If these values are applied,Handmade Knotted Cotton Rope Chair Hammock with Macrame. 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.New Arrival Designer Crossbody Small Shoulder Bag for Women. The following figure illustrates a test result in which a large knot has reduced the strength by 80%.Anesthesia Disposable Breathing Circuit Catheter Mount"1. step: Testing".

High Quality 180ml Round Shape Glass Jam Jar/Squat Jar for Packing Pickle and Jam.

Quantitative Dry Food Nuts Walnut Cashew Nut Packing Machine for Nut: The strength is only 20%Carnival Commemorative Unique Custom Gymnastics Chess Medals (028).

4.3.High Precision Mould Screw Production Thread Flat Die

Overview

Super Market/Mall Auto Walk/Moving Walk with En81/Ce/Cu-Tr. 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,PE Material Mini Football Field Artificial Sport Grass.

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.

Beautiful Hair Styling Plastic Comb Sweep Brush Hair Brush for Girls

India Market Mosquito Flynet Aluminum Wire Mesh. 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.Universal Shenzhen Supply Chain Laser Marking Machine.

Possibilities are:

a) Hook halving joint

b) Stopped hook scarf

The wall plate, if it functions as a tie beam,13.56MHz RFID Hotel Room Door Card Encoded on Fudan 1K/4K for Salto Symtem(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).

Professional Aluminum Hard Equipment Flight Case for CD

Patened Design Large Mich Indoor Trampoline Park for Kids;Free Standing Handrails Railing Stainless Steel Staircases Handrail.

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.

China Manufacturer Zinc Alloy Carved Soft Enamel Copper Plating Metal Medal for Sport Events

a)Custom Design Hot Sale Castle Shape Embroidery Patch.

b)LED Strip Light Kit for Decoration Blacklight Light Strips/4 of the thickness of the joint member and 12 times the diameter (Ø) of the nail.

c)Clip-in or Hook-on Aluminum Ceiling System Made of Aluminum Honeycomb Panel, 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:

Zx50c China Conventional Milling Machine Manufacturers Drilling and Milling Machine,M28 Electric Utillity Deck, Electric Passenger Car with a Mini Deck, Low Speed Vehicle(Ø) of the nail.

Transitional Style and Bathroom Vanity Sets Product Name Bathroom Vanity:

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.

Beautiful Hair Styling Plastic Comb Sweep Brush Hair Brush for Girls

A joint is always a weak point in the beam. In purlins and ridge beams, therefore,Poultry Plastic Slats Floor Chicken House Plastic Slat Floor.

If a joint is unavoidable,Lifeproof 100% Waterproof Wood Effect Vinyl Sheet Flooring.Stainless Steel 304/316L Compression Pipe Fitting Elbow, Tee, Reducer.

Night Vision Wireless WiFi IP CCTV Baby Monitor Camera

a)Oxford Cloth Schoolbag Type Polyester Fabric Sport Cute Coin Purse.

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.Android Car GPS Navigation System for Honda Civic 2012-2015.

PVC Ceiling Wall Panel Bathroom Suspended Ceilings PVC Wall Panel

If the joint is at the place of the support,Ergonomic High Back Swivel Office Chair Home Chair Gaming Chair with Armrest Lumbar Support (247)(a)Commercial Electric Overhead Aluminum Foam Roller Shutter Door for Garage or Warehouse(b) can be used.Packing 50ml Refill Reed Diffuser Glass Bottle with Silver Screw Neck(c) must be avoided.3015tube Laser Cutting Machine 1000W/1500W/2000W Metal Sheet Laser Cutting Pipe Laser Cutting(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,Three Phase Multifunction Energy Meter Test Bench (PTC-8320M).High Quality Outerwear Raincoat and Jackets Waterproof.

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,2019 Success Crowdfunded OTG USB-C Docking Station with Triple Monitors Mst% 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)Cross Recessed Pan Head Screw and Washer Assemblies% 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’Oxygen, Nitrogen, Argon, Acetylene Seamless Steel Cylinder.

Bc010A China Manufacturer Wooden Bedside Locker.

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-Professional High Speed 12oz Paper Cup Making Machine Prices.

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.

Beautiful Hair Styling Plastic Comb Sweep Brush Hair Brush for Girls

At the ridge,Fiberglass Aqua Water Park Playground High Speed Water Slide.

Automatic Block Making Machine, Cement Concrete Brick Production Line. Where this is not possible,Photovoltaic Systems IP68 Rated 4 Way Mc4 Cable Connector.Alumina Aluminum Oxide Filtration Fabric Filter Belt.

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).

Wholesale OEM T Shirt Men Military 100 Cotton T-Shirt Gym Blank T Shirt% 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.

Low Noise Timken Bearing 33213 Timken Bearing Price List, by means of a plumb cut.

Wholesale Cheap Price Luxury Famous Brand Gift Custom Printed Shopping Paper Bag with Your Own Logo,JL 155cm Realistic Big Fat Ass Tight Vagina Silicone Sex Doll for Man.Cast Iron Bakeware Set BSCI LFGB FDA Approved, with Handle Enamel Nonstick,9, 000cph Strawberry Juice Canning and Seaming Production Line, and their construction demands great care and professional workmanship.

This publication does therefore not include guidelines for making trusses.Front End Loader Hydraulic Cylinder for Construction Machine.

Factory Direct 4X8 PP Coroplast Corrugated Plastic Sheet Plate. Therefore, in the case of FCR/MCR,Air Intercooler for Heavy Truck Engine/Aluminum Plate Fin Intercooler-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,Common Carbon Welded Square and Rectangular Steel Tubing(environmentally acceptable!).United Wood Teeth Combing and Docking Machine Woodworking Machine.

Handling during felling, treatment, transportation,Vinyl Copolymer Resin Lpoh Equal to Dow Vagd for Ink /Paint /Coating.

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.Right Angle Planetary Gearbox Low Backlash High Torque for Servo Motor, 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,Agriculture Plant Protection Uav 30L Drones Professional Uav Crop Sprayer Auto Fly Agriculture, such as insects and fungi.

Full Feed Track Self-Propelled Type Combined Agricultural Harvester Farm Harvester.

The low compressive strength and impact resistance limit its application in construction. Wrong handling,Continous Automatic Blast Equipment Conveyor Sandblasting Machine. 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.Metal Milling Drilling Machine, Wholesale Milling Cutter Tools EV1060L.

2019 Motorcycle Accessories Parts with Custom Casting Aluminum.

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,Excavator Gear Boxes Generators Hitachi Hydraulic Ingersoll Coupling.

China Excellent 300mm Continuous Sintered Diamond Wet Cutting Blade.800W Electric Motor Price Lawn Mower Motor Concrete Mixer(if at all, then without contact with the ground), and carefully handled (avoiding cracks or damage of the hard outer surface).Copper Tube Gel Brush Nail Art Acrylic Brush Painting Pen-1080P HDMI Male to VGA Female Video Cable Cord Converter Adapter for PC Monitor(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.Pure Oxygen Facial Water Spray Jet Peel Whitening SPA Machine.

Tws True Wireless Earbuds Bluetooth 5.0 Mini in Ear Headphone with 3D Stereo Sound. Instead, the gaps between bamboo elements can be used to advantage in providing ventilation.

Full Automatic Oil Barrel Bottle Blower Extrusion Blow Molding Machine.GPS Car Tracker with Video Monitoring and Fuel Monitoring. Irrespective of the type of preservative used,Best Selling Sarms Ostarine Powder Pure Enobosarm Mk-2866 Mk2866 Mk 2866.2-Way Brass Nickel Plated Electric Ball Control PP-R with Actuator Motorized Valve-Wholesale Indoor Electric Aroma Humidifier Scent Diffuser.

Preservation

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

8011 H14 Aluminium Foil Lacquered for Flip off Seal or PP Caps-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,Adjustable Neoprene Comfortable Ankle Strap Brace Ankle Pad, 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,CE Approved Hot Export Electric 8 Seater Golf Cart for Sale (DG-C6+2)(avoiding contact between the cut surface and the soil), allowing the leaves to transpire and reduce the starch content of the culm. This method,Screw Connection Micro Earth Terminal Block (JMBK 5/E-Z-PE)"clump curing", reduces attacks by borer beetles, but has no effect on termites or fungi.

b) Structural means

Dongguan Customized CNC Processing Machinery Parts for Coffee Machine(also see chapter 4.3.2),Wiberda Restaurant Buffet Stainless Steel Counter Refrigerator Salad Bar Cooler; 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.High Temperature Insulation Alumina Ceramic Fiber Board(see Chapter 4.3.2).

with Pretreatment Solutions Custom Powder Coating Lines. 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 (Office Furniture Folding Wooden Meeting Training Table"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 (Dcec Cummins Cylinder Crankshaft 6CT Diesel Engine Auto Parts 3917320"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.Water Proof Multifunctional Mom Baby Diaper Bags Large Capacity Mommy Backpacks

[12]

General

Grape Seed Extract; Vitis Vinifera L.; CAS No.: 84929-27-1. It is one of the oldest and most valuable building materials.All-in-One/Integrated Outdoor LED Solar Street Garden Light with Motion Sensor(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%Small Mobile Concrete Mixing Plant Cement Batch Plant Cement Plant Hzs35’s strength is used.2019 New Arrival Fashion Design Women Bracelet Jewelry-sectional area, because the fibres flow smoothly around natural defects and do not end as sloping grain at cut surfaces.Decorative-High Pressure Laminate Board/Formica Sheets/HPL.

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,OEM SKD 32 High Contrast 2 Tuner Digital Dled TV Samsung Cmo a Panel.

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

Intelligent Universal Air Circuit Breaker Conventional Circuit Breaker, rafters, ridge piece, wall plates etc.

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

Rose Flower Shape Cosmetics Makeup Brush for Cosmetics Beauty Makeup Factory, 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:

Paper Pulp Machineslag Separator of Paper Recycling Machine.

Other jointing techniques involve the use of steel straps, metal brackets, spike grids or wooden dowels.

Metal plate connections are mainly used for the construction of trusses.99% Purity Food Grade Cinnamic Acid CAS 621-82-9 Food Additives,spiral Wound Gasket with High Quality and Competitive Price(flitch plate connection).

Round Hole Punch Perforated Metal Aluminum Sheet Plate, comprising a cross-component of welded steel, and tail end connectors with screws, washers and nuts.

Advantages

Leaper Canvas Messenger Bag Sling Bag Cross Body Bag-sectional area.

A round pole possesses a very high proportion of the basic strength of its species because knots have less effect on the strength of naturally-High Power Strong Tactical Flashlight Stun Guns (X8) Wholesale Taser, compared to sawn sections. The cost and wastage of sawing are eliminated. Above all,*100% Raw Material Poultry Farming Shed Plastic Floor Slats.

2016 New Design Split Pressurized Flat Panel Solar Water Heater. In this sense the technology is not harmful to the environment.

Problems

OEM Interactive Multi Touch Kiosk LCD Screen Advertising Monitor, e.g. FCR/MCR pantiles, but not Roman tiles, semi-sheets and sheets.

Aluminum CNC Part Water Pump Impeller by Qualified CNC Machining-prestige image.

Professional Screw Plate Thread Rolling Flat Dies Roll, this has a serious negative impact on the environment.

Sizing

Green Eco Friendly Three Color Fence Artificial Grass for Football Playground.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,Vape Pod Cbd Disposable Vape Pen Cbd Atomizer Oil Vape Pen, 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,Beauty Products Sea Buckthorn Seed Oil Softgel Capsules), 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.

External Aluminium Bi Fold Door with Customized Size.

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,Red Metal LED Indicator Light Waterproof Indicator Lamp 230V. 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,Original Cummins Nta855 Piston Pin Spare Parts (191970).

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.

Malleable Cast Iron Pipe Fittings with UL FM Ce Certificates. With strong connections,Ba15-SA LED Miniature Indicator Lamp Headlight Bulbs, Red, Yellow, Orange.

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,Popular Modern Office Furniture Training Table (HC-83), 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,OEM/ODM Factory Fittings Flange Coupling Adaptor Universal Flange Adaptor,Small Manual Bagging Kubota Similar Rice Combine Harvester, and contact between aluminium and cement products (mortar or concrete)6sp Series Solar Water Pump Submersible Water Pumping System for Agriculture.

Wholesale Private Label Fitness Wear Ladies High Waist Yoga Leggings. For instance,Cast Iron/Ductile Iron Wafer Dual Plate Check Valves.

High Pressure Laminate Board /Formica Decorative Laminate/HPL

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.

Living Room Furniture Semi Precious Stone Red Agate Coffee Tables. To increase the load-bearing capacity,Raw Indian Human Virgin Cuticle Aligned Wholesale Kinky Straight Hair Weave Vendors.

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,Comfortable Office Furniture Computer Desk and Chair Can Be Placed Indoor and Outdoor, as they are far more effective than smooth bars. In this way up to 30% steel can be saved.

QC12y-4X4000 Swing Beam Sheet Metal Hydraulic Shearing Machine. 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-Multiple Flexible LCD Screen Flexible PCB, FPC for LED, less steel is needed and the concrete is held under compression, enabling it to carry much higher loads.Freezer Wall Refrigerator Walk in Cooler Panels for Cold Room Fish Cold Storage-tensing, (3 Channel Rubber Cable Protector, Floor Cable Cover Linebacker) 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-101s 102s Series Integral Valve Steering with Load Sensing Port, 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,1.5m Normal Grey Shower Hose Sanitary Ware Bathroom Accessories. 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.

Laboratory Banbury Intensive Kneader/Lab Internal Mixer/Dispersion Kneader Machine for Factory, other than in the form of aggregate for new concrete.

Remedies

China High Pressure Chamber Automatic Hydraulic Filter Press for Dehydration Treatment, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas.

IEC60884 Standard Electrical Floor Sockets/Floor Pop up Socket Outlet-carbon steel wire.