/
BUILDING TECHNOLOGY BUILDING TECHNOLOGY

BUILDING TECHNOLOGY - PowerPoint Presentation

faustina-dinatale
faustina-dinatale . @faustina-dinatale
Follow
387 views
Uploaded On 2017-11-06

BUILDING TECHNOLOGY - PPT Presentation

REVISION HANDBOOK 2 THE BUILDING TEAM THE BUILDING TEAM Building is essentially a team process in which each member has an important role to play Below are some key points and a typical organization structure of a team for a large construction project ID: 603209

timber concrete wall building concrete timber building wall cement water walls wood site foundation framing block aggregates moisture type

Share:

Link:

Embed:

Download Presentation from below link

Download Presentation The PPT/PDF document "BUILDING TECHNOLOGY" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.


Presentation Transcript

Slide1

BUILDING TECHNOLOGY

REVISION HANDBOOKSlide2

2

THE BUILDING TEAM

THE BUILDING TEAM

Building is essentially a team process in which each

member has an important role to play. Below are some key points and a typical organization structure of a team for a large construction project.KEY POINTSThe client decides that a building is needed and employs the building and design teamThe architect, who is a key member of the design team, designs the building for the client. Other members of the design team are: the structural engineer; the quantity surveyor; the clerk of workThe building team works for the client, but follows the design teams instructionThe main contractor constructs the building with assistance from subcontractorsSkilled technicians assist all parts of the building processBuilding merchants supply the building materialBuilding inspectors are responsible for building regulations Planners control the overall design and siting of building projects

QUANTITY SURVEYOR

ENGINEER

ARCHITECT

BUILDING OWNER/CLIENT

PLANNING AUTHORITY

LAWYER

BANKER

CONTRACTOR

CLERK OF WORKS

NOMINATEDSUB-CONTRACTOR

OPERATIVES

ADMINISTRATOR

BUYER

ESTIMATED

SURVEYOR

CONTRACTS MANAGER

ASST. CONTRACTMANAGER

DOMESTICSUB-CONTRACTOR

OPERATIVES

COSTING

ACCOUNTS

OFFICE STAFF

Module D12 Building Teams and Building TradeSlide3

Functions of the members of the Building TeamClient

– the person who commissions the work and directly or indirectly employs everybody on the project.

Architect

– engaged by the client as his/her agent to design, advise and ensure that the project is keeping within cost and complies with the design. Contractor – employed by the client on the architect’s advice to carry out the constructional works. He takes his instructions from the architect. Engineer – a specialist such as a structural engineer employed to work with the architect on particular aspects of the design. Quantity surveyor – engaged to prepare bills of quantities, check tenders, prepare interim valuations and advise the architect on the cost of variations Slide4

Building TradesThe building industry has a number of trades associated with it. These include:

Carpenter

Mason/

tiler

PainterElectrician Plumber Slide5

Responsibility of members of the Building Trade

Carpenter

– erects structural framework and constructs roofs

Electrician

– carries out wiring works and installation of fixtures Plumber – lay pipes, install taps, toilet bowls, etc. Painter – responsible for finishing the building by applying paint, wall paper Mason/tiler – works with concrete and mortar, lay concrete blocks, plaster walls etc.Slide6

6

FACTORS AFFECTING CHOICE OF A BUILDING SITE

KEY POINTS

ZONING

-is the legal identification of lands for specific use. The general categories of zoning are:-Residential, Commercial Industrial and Agricultural.OTHER FACTORSLand use - be sure that it can be used for the intended purpose.Ownership - ownership, certified by a deed (legal document) must be established before any final decision is taken regarding purchase of any lands.Boundaries - must be established and supported by a survey drawing before the actual size of property can be ascertained.Shape – when purchasing land, the shape of the lot (plot) should reflect the proposed shape of the structure within the framework of the legal restriction.

Size – minimum sizes of building lots are usually specified in order to ensure that: - legal requirements of set-back and off-set distances are satisfied.

Topography – is the shape of the surface of the land. This shape is sometimes referred to as “contour” and be classified as follows:

Flat/Undulating/Gently slope/Steeply slopedModule D2 Preliminary Site WorkSlide7

7

History –

is the study of past events associated with the use of the site. Historical issues that should be of concern to the purchaser are:

Water – whether natural water course, springs or flooding are associated with the site.

Dump – whether the site was ever used as a dump.Original topography – whether the land was filled.Access – all lands not immediately adjoining a street or publicpathway requires some means of access. This access influences movement to and off site during construction stage as well as normal occupancy.Unit cost – is the price per square foot or meter of the land. This unit cost is normally associated with:Level of developmentAvailable amenitiesAvailable servicesLocationZoneDemandTopography.Slide8

8

STRIPPING AND CLEARING OF A BUILDING SITE

STRIPPING

is the removal of topsoil from the construction area. Stripping should include pathways and aprons.REASONS FOR STRIPPINGStripping helps to provide a sound and level platform as well as to remove vegetable matter. Soils containing a high level of vegetable matter tend to:Support plant lifeBe very unstableAffect some building materialsA site is usually stripped to a depth of about 150mm/6’’ using a bulldozer.CLEARINGClearing is not necessarily part of stripping but for undeveloped sites, clearing is essential.

REASONS FOR CLEARINGThe removal of trees, which sometimes may obstruct the building process. OR

Traffic flow on site.The removal of obstacles like derelict buildings, vehicles, large boulders

or debris that may hinder the building processSlide9

One of the first jobs is to lay out the site boundaries, this is known as hoarding. This is done for the following reasons

:

Reasons for hoarding

: - Public

protection - Material/equipment protection - Security - Reduces vandalism - Prevents interruption Explanatory notes for reasons given: Public protection – to reduce the risk of accidents by keeping activities on the site away from outside personsMaterial/equipment protection – to reduce theft of materialsSecurity – to ensure workers and equipment are safe on the site. Reduces vandalism – prevents persons from interfering or destroying items on the site.Prevents interruption – persons or animals from the outside would not be able to distract workers on the site HoardingSlide10

Lay out simple building/structure

Peg

the

outside corners

: Determine the location of the building in relation to other buildings and boundaries (as usually shown on the site-plan or other relevant plan), and place pegs in the ground marking the corners of the buildingSteps in laying out a Square BuildingCheck to see if the pegs are square and form an exact rectangle. This can be done by making sure that: 1). Line AA-CC and line BB-DD are parallel. Line AA-BB and line CC-DD are parallel.(as shown in the drawing below) 2). The distance between peg AA and peg BB is the same as the distance between peg CC and peg DD. 3). The distance between peg AA and peg CC is the same as the distance between peg BB and peg DD.

4). The distance between peg AA and peg DD (the diagonals) is

the same as the distance between peg BB and peg CC. Slide11

Simple Building Squaring: The 3–4-5 Method

Here is a simple way of squaring a structure you are building outside.

1. Nail three pieces of timber together which you cut to these lengths to make a frame

750mm 1000mm 1250mm A frame with a right corner is called a square. 2. Place the right of the square against the lines between the corner . If the corner are not at right angles then move the corner pegs until they make right anglesCorner post3-4-5 triangleSlide12

Checking squareness after setting out

Main setting out lines

Profile boards

Diagonal

checks

The other method of checking squareness

of

a building is to check the

diagonal. If the diagonals are of equal lengths then the building is squareSlide13

13

TEMPORARY SERVICES ON A BUILDING SITE

DEFINITION

Temporary services

relate to the provision of utilities for the purpose of facilitating construction activities as well as providing convenience for workers. These supplies normally include: gas, water, compressed air, electricity and telephone.CONVENIENCESThese include convenience for personnel and work processes.PERSONNEL: Temporary services assist in the provision of drinking water, adequate lighting and toilet facilities.WORK PROCESSES: Utility supplies to the site can be used to drive (power) plant and equipment or provide ingredients for preparing certain materials.Examples of supplies used for driving plant and equipment are:Air – pneumatic tools and equipmentOil and gas – turbine and hydraulic tools and equipment.Electricity – electric tools and equipmentHeat, water and air are used in the following processes:Heat – asphaltic processes

Water – mixing concreteAir – spray painting, excavating compacting

COMMUNICATIONCommunication includes physical and verbal contact between the various agencies and processes during the life of the project. Factors to be considered are temporary roads for access to the site and storage areas, as well as possible telephone or two-way radio contacts.Slide14

14MANUFACTURING PROCESS OF PORTLAND CEMENT

WHAT IS CEMENT AND HOW IT IS MADE

Cement is a fine, soft, powdery-type substance. It

is made from a mixture of elements that are found

in natural materials such as limestone, clay, sandand/or shale. When cement is mixed with water, itcan bind sand and gravel into a hard, solid masscall concrete.Step 1Limestone is taken from a quarry. It is the majoringredient needed for making cement. Smaller quantities of sand and clay are also needed.Limestone, sand and clay contain the fouressential elements required to make cement. Thefour essential elements are calcium, silicon,aluminum and iron.

Module D3: Building Material Slide15

15

Step 2

Boulder-size limestone rocks are

transported from the quarry to the cement

plant and fed into a crusher which crushesthe boulders into marble-size pieces.Step 3The limestone pieces then go through ablender where they are added to the otherraw materials in the right proportion. Step 2Step 3Slide16

16

Step 4

The raw materials are ground to a

powder. This is sometimes done with

rollers that crush the materials against arotating platform.Step 5The rawmix or slurry is fed into a slopingkiln which is fired from the lower end by oilor pulverised coal to a temperature of2000 F or 1500 C by the time it reaches thelower end the water has evaporated andfusing of materials takes place formingclinker.Step 4

Step 5Slide17

17

MANUFACTURING PROCESS OF PORTLAND CEMENT

Step 6

The clinker is cooled and ground into a

fine gray powder. A small amount ofgypsum is also added during the finalgrinding. It is now the finished product –Portland cement. The cement is then stored in silos (largeholding tanks) where it awaits distribution.The cement is usually shipped in bulk inpurpose-made trucks, by rail or even bybarge or ship. Some is bagged for thosewho want small quantities. Slide18

The five easy steps in the production of Portland Cement

Crush and grind raw material

Mix the material in proportions

Heat and prepare mixture in rotary kiln

Grind the heated product known as clinkerMixing and grinding of clinker with gypsumTYPES OF PORTLAND CEMENT

Five common types of cement

Type I or Normal

This type is ordinary Portland cement. It has normal qualities, a reasonable setting time.

USES: For general concrete work, when conditions are normal- including masonry work rendering, filling of pockets ordinary strip foundation in concrete.

2. Type II – Moderate (sulphate resistance)

This type of cement gives off less heat than type I and has moderate resistance to sulphate. USES: Suitable for uses in foundations where there are low levels of sulphate but offers good resistance to soil in which there are high levels of sulphate.

3. Type III – Low Heat

This type is ideal for use in mass concrete work, such as large foundations or dams retaining walls. It develops strength slowly and generates less heat thus reducing cracking.4. Type IV- High Early- Strength or Rapid Hardening

This cement is used when the weather is bad (rainy season) or when formwork has to be removed early. It develops strength earlier than types I and II.

5. Type V- Aluminium This type contains aluminium ore. It is darker in the colour than normal Portland cement. It hardens very rapidly and has great strength.Slide19

Concrete and Mortar

CONCRETE

Contrary to popular belief, concrete and cement are

not the

same thing; cement is actually just a component ofconcrete. Concrete is made up of three basic components: water, aggregate (rock, sand, or gravel)and Portland cement. Cement, usually in powder form, acts as a binding agent when mixed with water andaggregates. This combination, or concrete mix, will be poured and harden into the durable material with whichwe are all familiar. There are three basic ingredients in the concrete mix: Portland Cement Water andAggregates (rock and sand) Concrete is a composite material composed of a mixture of cement, sand, gravel and water in the correct proportion to form a paste that can be moulded into any shape. Concrete is used

for columns, beams, foundation etc. Mortar

is a mixture of cement, sand and water mixed in correct proportion. Mortar is used for making beds, for laying bricks and for rendering masonry

wallsWhen prepared concrete and mortar has to be mixed to a specific proportion depending on the job it required to do. the standard mix for small jobs are usually done in the ratio of 1:3:6.This represents a mix of 1volume of cement, to 3 volumes of sand, to 6 volumes of course aggregate.

Water- Water is needed to chemically react with the cement (hydration) and too provide workability with the concrete. The amount of water in the mix in pounds compared with the amount of cement is called the water/cement ratio. The lower the w/c ratio, the stronger the concrete. (higher strength, less permeability)

Slide20

20

BATCHING OF CONCRETE

Types of batching

Batching by volume

Volume batching is generally used but it is a less accurate method of mixing concrete. The measuringbox/bucket/wheel barrow is used to determine theamount of cement and aggregates. A change in themoisture content will impact upon the volume ofmaterials and affect the qualities of the concreteBatching by weightIn this method the ingredients are measured by weight.This is a more reliable system of batching that volumebatching. Variation in volumes owing to compacting is

eliminated when using this method.

The result of batchingStrength – in order to obtain maximum strength the aggregates must produce little or no voids in the concrete thus increasing its strength.

Economy- cost is a major factor in concrete work. Cost is influenced by careless use of ingredients. The most costly ingredient is the cement. A poor mix often increases the cost of the job or reduces the strength of the concrete.

Workability- this is the ability of the wet concrete to be placed and work with ease. The correct proportioning of the cement and the aggregates and water cement ratio enhances this property.

BATCHING PLANT

MIXING CONCRETE BY WEIGHT AND VOLUMESlide21

21

THE WORKABILITY OF CONCRETE

Pouring a concrete floor for a commercial building.

Adjusting the reinforcement bars during a concrete pour

A concrete slab ponded while curing.Slide22

22

AGGREGATES

Aggregates is the general terms for the sand and rocks used in construction. Fine aggregates are sand and coarse

aggregates are gravel or crushed stone. Aggregates are size graded and sold by set size categories, measured as

inches or millimetres.Requirements of Aggregates All aggregates should be:CleanFree from all sedimentStrong not easily crushedWell gradedWell shapedTypes of AggregatesCoarse Aggregate gravel consists of small pieces of stone which are somewhat rounded in shape. It makes good coarse aggregate because it is hard and closed textured. When using gravel as a coarse aggregate the pebbles should be graded in size – (Source – Gravel Bank, River Beds).

Crushed Stone trap rock is the hardest and most durable stone that can be crushed and used for making concrete. This stone is dark, heavy, close-grained, and of igneous origin. Granite makes good crushed stone and is less expensive than trap rock.

Fine Aggregates for concrete are sand and crushed stone or gravel screening. The most important of thee (by far) is sand. Sand is a finely divided material of rock or mineral origin which will pass through a standard 5 mm sieve. Sand is not subject to disintegration, decay or expansion.

All–in:

The term all-in is used for aggregates composed of both fine and coarse aggregates. A wide variety of material, for example brick, furnace slag, lightweight substances such as foam slag, expanded clay and vermiculite are available as aggregates for making concrete.Slide23

Slump TestThe slump test is carried out to measure the distance that concrete compacted into a cone will slump down when he cone is lifted from it. The slump will be the same for batches if the water content is consistent. Slide24

Placing ConcreteThe following are precautions to be taken when placing concrete:

Mixed concrete should be placed in its final position within half to an hour of mixing. This is because the initial setting of ordinary Portland cement takes place within this period of time. After this time, the concrete has lost some strength which can never be regained.

Concreting in hot dry weather poses particular problems with regards to placing. Moisture evaporates too fast rapid and this can result in a weak finished product.

When concrete is being laid in foundation trenches, in addition to the fast evaporation of moisture from the concrete, the dry trench absorbs moisture from the concrete. To limit this absorption, the trench should be watered down before the concrete is placed into it

Concrete shouldn’t be dropped from a great height, as this tends to segregate the aggregate. A height of 1meter is usually specified as the maximum from which wet concrete should be allowed to drop freelySoon after placing in the right position concrete should be compacted or consolidated. The purpose of compacting is to make the concrete as dense as possible by eliminating voids within it.All formwork must be plumbed, leveled and adequately supported.Slide25

CURING AND PROTECTING CONCRETE

Curing

is the process of limiting early loss of water from

concrete thus ensuring the continuation of chemical action. Losing too much water too early in the life of a concrete component causes high creep and shrinkage, and may even cause a significant loss of strength. Most importantly, poor curing is detrimental to the durability of the concrete, particularly the outer concrete which is required to provide protection to the embedded reinforcement. In general, the longer the period of curing, the better will be the quality of the concrete. This applies not only to its compressive strength, but also to its durability, its resistance to wear, weathering and chemical attack, and to its freedom from shrinkage cracking. Concrete therefore needs to be kept moist, both by the prevention of loss of moisture due to evaporation, and by the provision of extra water from outside the concrete.

There are two general forms of curing:• Keeping all concrete surfaces wet to prevent moisture loss (spraying with water)

• Creating a barrier to prevent moisture loss (sandbags, ponding)Slide26

26THE USE OF PLASTICS IN THE CONSTRUCTION INDUSTRIES

Properties of Plastics

Lightweight

Durable

Easily jointed or moldedGlazableElasticUses of Plastic in ConstructionElectrical conduitsWater seals, (DPC) Damp Proof Coarse, (DPM) Damp Proof MembranesFloor/roof tiles Decorative skirtings/mouldingsWater pipesDrain pipesConclusion:With the increase of modern technologyplastics have not only make a big impact in the construction industry but in other areas such as medicine (prosthetic, plastic surgery), transportation (vehicle manufacturing) and communication (fiber optic cables and cell phones).D3.2: Plastics and Water proofing MaterialSlide27

27GROWTH AND STRUCTURE OF TIMBER

The Parts of a Tree Trunk

Bark

Every species of tree has its own particular kind of bark. This is a means of identification. The bark is the protective coating of the tree.

Cambium LayerThis is the growing part of the tree trunk. Here new cells are constantly developing, some making bark and others making wood.SapwoodThis is found next to the cambium layer, and contains only a few living cells and functions mainly in the storage of plant food and the conveyance of sap. The sapwood varies in thickness from 13mm to as much as 150mm radial thickness in some species.Heart WoodIt consists of inactive cells that have slightly changed both chemically and physically from cells found in sapwood. These cells cease to transport sap. The cells of heartwood may contain minerals, which contribute to its darker colour, great beauty and resistance to decay.SECTION OF A TREE TRUNK

D3.3: Timber and Timber ProductsSlide28

28HARDWOOD AND SOFTWOOD

There are two main groups of timber producing trees used commercially; softwoods and hardwoods. These terms immediately create contention because they do not accurately describe the timber correctly.

Softwoods.

 

Softwoods are coniferous trees and the timber is not necessarily 'soft'. They are 'evergreen'. (The larch is an exception) Their general characteristics are:Straight, round but slender, tapering trunk. The crown is narrow and rises to a point.It has needle like or scale-like shaped leaves and it's fruit, i.e. it's seeds are carried in cones. The bark is course and thick and softwoods are evergreen and as such do not shed their leaves in autumn. Hardwoods. Hardwood trees are broadleaf and generally deciduous. Their timber is not necessarily hard. For instance, balsa (the timber used for making model planes) is a hardwood. The general characteristics are: Stout base that scarcely tapers but divides into branches to form a wide, round crown. The leaves are broad and may have single or multi lobes. The bark may be smooth or course and varies in thickness and colours.Its fruit may be: nuts, winged fruits, pods, berries, or fleshy fruits.Slide29

Density:

higher density thereby harder

Lower density thereby most varieties are softer than hardwood.

Found in regions:

Trees supplying hardwood are found throughout the world from the Boreal and Taiga forests of the North to the tropics and down into the far South, excluding Antarctica.

Found in the northern hemisphere.

Definition:

Comes from deciduous trees that drop their leaves every year.

Trees that are conifer and have needles, and normally do not lose needles.

Properties:

Broad leaves; enclosed nuts; higher density.

Less dense; less durable; high calorific values.

Type:

Mostly deciduous.

Evergreen

Cost

Expensive.

Less expensive.

Examples of trees:

Aspen, Poplar, Birch, Elm, Maple, etc.

Pine, spruce, cedar, fir, larch, Douglas-fir, etc.

Applications:

Used for furniture but less frequently than softwood.

Widely used as wood ware for building and furniture.

Hardwood

SoftwoodSlide30

30CONVERSION OF TIMBER

Methods of Conversion

Plain Sawing or Through and Through Sawing

– this method yields the maximum amount of usable wood from the log, but logs cut in this way will also include growth defects which may result in poorer quality timber.

AdvantagesMore lumber is producedIt dries more rapidlyIt is cheaperIt has a lower unit costQuarter Sawn – this method is used when first quality timber is required, however a fair amount of waste is produced from this method. This is one of the reasons for the high cost of good quality timber.AdvantagesLess tendency to warp or twistLess tendency to cut or twistLess shrinkageMore durability – strengthMore attractive grain patternMore rapid kiln dryingTangential Sawing – this method is used to get boards with the maximum amount of grain configuration suitable for decorative work. However due to the cost of producing this kind of timber the logs are cut into veneers instead.P.S. Any waste timber that occurs during conversion is recycled in the manufacture of certain building boards such as plywood.Slide31

31SEASONING OF TIMBER

Seasoning is the controlled process of reducing

the moisture content (MC) of the timber so that it

is suitable for the environment and intended use.

We need to reduce the MC of timber for the following reasons:Seasoned timber although lighter will be stronger and more reliable. The sap in timber is a food for fungi and wood parasites. Remove the sap and the wood will be less attractive to these dangers. For construction grade timber the timber must be below 20% MC to reduce the chances of Dry Rot and other fungi infestations. Dry well seasoned timber is stronger. Dry well seasoned timber is easier to work with and consequently safer especially machine working. Timber with higher moisture content is difficult to finish i.e. paint, varnish, etc. KILN SEASONING

AIR SEASONING Slide32

32

TYPES OF SEASONING

There are two main ways of seasoning timber,

Natural (Air) and Artificial (Kiln) drying. Both

methods require the timber be stacked andseparated to allow the full circulation flow of air, etc. around the stack.Air Seasoning.Air seasoning is the method used with the timber stacked in the open air. It requires the following:Stacked stable and safely with horizontal spacing of at least 25 mm. Vertical spacing achieved by using timber battens (piling sticks) of the same or neutral species.   Today some timber yards are using plastics.   The piling sticks should be vertically aligned and spaced close enough to prevent bowing say 600 to 1200 mm max centres. Ends of boards sealed by using a suitable sealer or cover to prevent too rapid drying out via the end grain. The stack raised well clear of the ground, vegetation, etc to provide good air circulation and free from rising damp, frost, etc. Over head cover from effects of direct sunlight and driving weather.

Kiln Seasoning.

There are two main methods used in artificial seasoning, compartmental, and progressive. Both methods rely on the controlled environment to dry

out the timber and require the following factors:Forced air circulation by using large fans, blowers, etc.

Heat of some form provided by piped steam. Humidity control provided by steam jets.

The amount and duration of air, heat and humidityagain depends on species, size, quantity, etc. Schedules are published for the various species to

enable operators to select an appropriate drying environment.   In the UK they are usually provided

by the Kiln Manufacturers and also published in the Handbook of Hardwoods and Handbook ofSoftwoods (BRE).Slide33

Calculation of moisture content

As mentioned before , for stability, timber should have a 20 percent moisture content, which is close to the moisture in air.

The formula for calculating the moisture content is:

Weight of sample with moisture

dry weight ExampleA piece of timber weighs 132.5gIts dry weight is 108.7gThe moisture content weighs 23.8gThe percent of the moisture content is(23.8/108.7) x 100 = 21.9percentx100Slide34

Defects in Timber

Defects that develop after felling the tree.

Bow

CupTwistRadial shakesWaneDiagonal grains

The defects that usually occur in the timber may be classified into two categories as follows:

Defects that develop during growth of the tree.

Shakes

Twisted timber

Upsets or

rupture

Knots

Wind cracks

Burls Slide35

Defects that develop during growth of tree have been briefly discussed as follows:

1.1

Shakes.

This is most serious type of defect in timber. These are sort of cracks which partly or completely separate the fibers of wood. A shake is nothing, but separation of the timber along the grains. Shakes may be of several types.Defects in Timber

1.1.1

Star shakes

These are radial cracks or splits that extend from bark towards the sap wood. They usually remain confined up to the plane of sap wood only. The cracks are widest at the circumference and go on narrowing as they proceed towards the Centre of the tree. Slide36

Reasons

of star shake

Star shakes usually develop due to fierce heat and frost

When logs having this defect are sawn they usually separate out into a number of pieces and hence become useless.Defects in TimberStar shakesSlide37

1.1.2

Heart shakes.

These splits or cracks occur in the central part of the trees. There are widest at the centre and go on narrowing as they proceed towards outside. This defect usually occurs in over-matured trees. This defect is usually caused due to shrinkage of the heart wood. Heart shakes divide the tree cross-section into several parts. Straight running heart shake is not as serious as twisted heart shake.

Defects in Timber

1.1.3Cup shakes

.

This defect develops curved slit between successive annual rings. The split does not run for the full circumference of the annual rings. This defect usually develops due to:

1

.

unequal growth.

2. Another possible reason for their development may be contraction of timber under atmospheric changes together with the twisting action of strong winds.Slide38

1.4 Knots.

Knots

are generally developed at the bases of branches cut off from the tree. This phenomenon ultimately results in the formation of dark, hard rings, known as knots. As knots break the continuity of the wooden fibers, they form a source of weakness. The amount of weakness caused by the knot depends upon the position, size, and degree of grain distortion around it. Knot is the most commonly encountered defect of wood.

Defects

in TimberIt is impossible to procure timber free of knots. Knots may be dead, live loose, or tight. Tight knots are not objectionable unless they

are too large. Their presence on tension members is objectionable. It is very difficult to plane

the timber at knotsSlide39

2. Defects that develop after felling the tree.

Conversion

of timber is done almost immediately after felling The tree. The defects that may

develop after

felling the tree and also during conversion and seasoning are the following:2.1 Bow: when planks of converted of timber shrink and bend in curved form , in the direction of length.Defects in Timber2.2 Cup:

this defect is indicated when wooden planks bend in curved from in transverse direction.

2.3 TwistA plank which has distorted spirally along its length Slide40

40

Preserving Timber

Timber should have two types of preservation applied

Treatments of resist attack by rot fungus and wood-eating insects.

Treatment such as paint, polish or vanish to protect it from moisture and pollutionTimber to be treated with preservative should be cut, shaped and prepared in advance of the building work. Ant cutting afterwards exposes untreated timber, which must have liquid preservative applied by hand.Two methods can be used to treat timber: pressure impregnationSteeping or immersionPressure impregnation is a method whereby you put the timber in a kiln or other container and create a vacuum inside by pumping out the air. You use pressure to force the preservative deeply into the timberSteeping or immersion is a method where you put the timber in a tank filled with preservative. The timber absorbs so much liquid that it is full of the chemical preservative when it dries out againAdvantages of Treated TimberIt provides long life under hazardous conditions. It is cost efficient. It is versatile – can be used outdoors, indoors, above ground, underground, and in direct contact with fresh or salt water. A variety of finishes provide additional attractiveness. It provides flexibility for design and can economically overcome difficult site situations.

Slide41

41

MANUFACTURED BOARDS

Manufactured or man made boards

- are made from wood products and have new/different

properties to the wood they were made from. Board sizes are 8ft x 4 ft (2440 x 1220 mm). Properties of Manufactured board:Larder size the nun manufactured boardUniform textureSmooth surfaceStandard dimension 8ft x 4ft (2440 x 1220mm)MDF (medium density fibreboard) made by a process which glues wood fibres together using heat and pressure. The boards are smooth and strong. They are resistant to warping. They have a layered structure which makes fixing to the edges difficult. MDF is a board used industrially for the production of furniture (especially shelves and cupboards). Special fixings have been designed to enable MDF to be joined effectively. Dowel joints can be used. The router can be used to cut rebates and housing joints, which work well on MDF. Dust is a problem when working with MDF, dust extraction systems should be used when machining it. Face masks can also be used to reduce the problemPlywood is made from layers of thin wood glued together at 90 degrees to each other, this makes plywood very strong as it cannot split along the grain like solid timber. If waterproof glue is used the plywood can be used in damp or even wet conditions. Marine ply can withstand sea water. Aero ply is made from three thin layers of birch and is only one mm thick when bonded together, this ply was designed to be used on aeroplane wings as it can be curved so effectivelySlide42

MANUFACTURED BOARDSHardboard

manufacture

consists

of breaking down wood into its basic

fibers then putting the wood back together with the fibers rearranged to form hard panels which have their own set of separate and distinct characteristics. In a most real sense “hardboard” is hard board. It is made in sheets in a wide variety of thicknesses but most commonly 1/8” to 1/4”. It is made from wood but is more dense. Placed in water many hardboard products will sink or barely float. It is hard on saws.Slide43

Ironmongery

D3.4: IronmongerySlide44

44FOUNDATIONS

FOUNDATIONS

The foundation is the part of the construction

where the base of the building meets the ground.

Function of a foundation is to transfer the structural loads from a building safely into the ground. It also, anchors the building and provides stability TYPES OF FOUNDATIONSStrip FoundationsStrip foundation as the name implies are continuous strips of mass concrete or reinforced concrete or stone laid at a pre-determined depth below ground level and along the position of the load bearing walls only.These types of walls are suitable for boundry walls, retaining walls and domestic building not more than three stories .

D4.1: Types, Function and Construction of FoundationsSlide45

Details of the Cross section of a Strip FoundationSlide46

Other types of Foundations

Raft foundation

This foundation consist of a

continuous reinforced concrete

slab under the whole building. Using this type of foundation the weight of the building is evenly distributed across the area of thefoundation. For ordinary housingpurpose, a raft of 150mm – 250mmthick reinforced concrete is sufficient. Slide47

These may be circular, rectangular

Or square in section. The most

Common types are square. They

May be of mass or reinforces

concrete, but reinforced concrete pads are reserved for large type of structures. They are generallyused to support isolated loads such as those in columns, piers and heavy machinery in factories.Pad foundation Slide48
Slide49

Pile Foundation

This type of foundation uses piles to transmitting load from

a building to a bearing stratum where such a stratum

underlies a depth of weak upper soil.Slide50

Foundation Components

(to attach wood stud sill plate)

(to keep water off of foundation wall)

(separates slab from foundation wall)

(to keep water off of slab)(to keep water off of slab & moisture barrier)(moves water away from building)

(moves water away from building)Slide51

Site Preparation

Remove trees and any debris

Remove top soil (4-6” below surface)Slide52

Site Layout

Ensure lot lines are known & setbacks are complete

Layout building

perimeter

Use batter boardsEstablish building corners & building perimeterUse surveying instrumentsSlide53

Excavation

Excavate foundation along line created by batter boards

Excavate remainder of soil inside perimeter

Don’t

excavate inside soil if slab on gradeIf deep foundation, taper edges to prevent collapseIf soil unstable, or very deep - use shoringSlide54

54

EXCAVATION AND TIMBERING TO TRENCHES

Excavation

The method of excavation can either be manual or mechanical.

Manual excavation is used extensively on small domestic structures. The manual process requires hand tools such as Pick Axe, Shovel/Spade, Digging Bars, Forks, Hoes and Diggers.MechanicalMachines now perform the bulk of excavation on major building projects. The principal machines are: Dragline, Bulldozer, Front end loader and Back hoeTimbering To TrenchesTimbering is the temporary support used at sides of trenches to prevent caving in. The support given to the sides of the trench depends upon the depth of the trench and the soil conditions. Weak soils will require more elaborate temporary support.Types of TimberingOpen Boarding – this is used for moderately firm ground such as sandy gravel, soft dry chalk and firm clay.Poles and Struts – these are used for moderately firm ground, such as stiff clay, firm gravel and hard chalk. The poling boards are spaced 1.8 m apart.Close Boarding or Sheeting – this is used for unstable ground such as loose sand; wet soils and made up grounds.Slide55

Module D5: Walls

Definition

A wall is a continuous, usually vertical, solid structure of brick ,stone, timber or metal

which encloses and protects a building or serves to divide buildings into compartments

or roomsThey carry and transmit to the foundations the imposed vertical loads from other Building elements(beams, floors, and roofs) and ensure the stiffness of the whole structure. They also protect the structure from the horizontal actions of wind and earthquake, acting as wind bracing.Walls are defined as external or internal to differentiate functional requirements, and also as load bearing or non-load bearing to differentiate structural requirements.Load bearing walls, those that carry imposed loads, such as those transmitted by floors, roofs…;Non-load bearing walls which can carry just their own weight and if they are made of masonry are termed panel walls;Non-load bearing walls supported by other structural elements, those related to a framed structureSlide56

Functional requirementsThe function of a wall is to enclose and protect a building or to divide space within the building. The main functional requirements are:

1) Stability

2) Strength

3) Durability

4) Weather resistance 5) Fire resistance6) Thermal insulation7) Sound insulationSlide57

Bonding

In building a wall of brick, it is usual to lay the bricks in some regular pattern so that each brick overlaps partly two or more bricks below itself. The bricks are

said to be bonded

, meaning that they bind together by being laid across each other

. Three types of bond, the patterns in which the bricks are laid, are shown below:English BondFlemish Bond

Stretcher BondSlide58

Setting out openings in WallsOnce the wall reaches ground level thought must be given to the position of the different openings. These openings are usually for doors, windows, frames and arches.

The following terms are used when dealing with masonry:

Lintels

: Steel reinforced- concrete beams used for support over windows and

doorsLaying Block: The process of mixing mortar, applying it to masonry block, and placing the block to create walls.Course: A row of masonry unitsMasonry: Anything constructed of brick, stone, tile, or concrete unit held in place with portland concreteConcrete Sills: Used under windows and doorsFooter or Footing: A continuous slab of concrete which provides a solid, level

foundation for block or brickSlide59

Notes:

1. Door openings will have 2" jambs on both sides and top.

2

. Door will be a standard height (44" x 6'8"). 3. Door sill will accommodate a concrete floor inside.

4. Window openings will accommodate standard size windows.

5. Space above the top of the door will accommodate appropriate trim under the eaves of the roof.

6. Reinforced concrete lintels carry the weight over door and window openings.

7. There are no cut block in the wall. Therefore, the wall can be built with a minimum of cost and labor.

A building front laid out using only whole and half block.Slide60

Procedure for laying blocks

A. Spread a layer of mortar called a mortar bed as the footer.

B. Position the block on the mortar bed so that its outside corner rests

there

the outside corner of the wall should be. Level the block by first placing the level across the block and then lengthwise along the block.C. Turn several stretcher blocks on end and apply mortar to the ears with a wiping or swiping stroke of the trowel. D. Lay several stretcher blocks in place by working away from the end or corner block.E. Use the end of the trowel handle to tap the block until each block is plumb, level, and the course is straight. F. Apply a mortar bed on top of the first course in preparation for the second course.G. If extra strength is needed in the wall, install reinforcement in

the mortar bed. Slide61

Procedure for laying blocks

H. As the block laying progresses, cut off excess mortar with the trowel.

I. Use a line to keep the courses straight. The line is positioned to be level along the top of the block.

J. When a block must be cut, use a mason

=s hammer and make multiple strikes along the line to cut; then make one sharp strike on the web.K. Check the height to be sure each new course is an additional 8 inches high.L. After the mortar dries and hardens slightly, finish the joints by rubbing it with a broken piece of block.M. If a joint other than a flush joint is desired, use a jointer to compress the mortar and create a watertight joint. Tools are available to create joints that are concave, v-shape, flush or raked. Slide62

Showing procedure in laying concrete block wallsSlide63

The usual practice in applying mortar to concrete blocks Slide64

A method of laying concrete blocks. Good workmanship requires straight courses with the face of the wall plumb and true.Slide65

Wall Framing

Wall framing is built upon the same sheathing module that floor framing used – covered with sheets 48” by 96”. The standard spacing for wall studs is 16”

o.c

. 15 1/4” must be used at the beginning of marking out a wood frame wall.Slide66

Wall Framing

Wall framing is done with standard members for the areas around openings, at corners, and at intersecting partition walls. Slide67

What are the parts of a framed wall?(Figures 1)

Sole plate

Stud – usually placed 16” or 24”

o.c

. (on centerCripple & trimmer studs – used in corners, window and door openingsHeaderTop plateSlide68

Material informationWhat lumber sizes are used for the studs and plates?

- 2 x 4’s or 2 x 6’s, depending upon climate or desired insulation

What lumber sizes are used for the headers?

- 2 x 10 or 2 x 12Slide69

Wall framing members

-

cripple studs

are shortened studs that end because of an opening

- trimmer studs are shortened studs that support rough openings and the weight of the header - headers carry the weight of a building across rough openingsSlide70

Wall framing members (cont.)(Figures 2)

- header length = rough opening + width of trimmer studs

- headers are required across openings in load-bearing partition walls

- headers are usually two framing members nailed together (w/ plywood or insulation in between) to equal a wall’s thicknessSlide71

Plate Layout(Figure 9 – 12)

What is the first step of plate layout?

- marking the location of the studs

Before the wall is nailed in place, what needs to be checked for?

- Always check for square!- Temporary bracing should be installed to hold a wall in place until it is sheathedSlide72

Interior wall partitionsWhat can construction of interior walls begin?

- After completion of the exterior walls

- Load bearing partitions are installed firstSlide73

Special considerations in framing

The rough-in process will require the drilling or notching of studs – wooden bracing may need to be installed

Why is the top plate doubled in wall framing?

- Extra ceiling and rafter support

- Other special framing may take place with large windows or cabinet soffitsSlide74

Wall sheathingShould be completed before roof framing begins

What materials are used in the sheathing of exterior walls?

- plywood, house wrap, masonry materials

-

House wrap is designed to cover cracks in wall joints where air may travel through a buildingSlide75

Wall sheathing (cont.)What materials are used to cover the interior walls?

- drywall, paneling, masonry materialsSlide76

Partition IntersectionWhere partitions meet outside walls, it is essential that they be solidly fastened. This requires extra framing

The framing must also be arranged so inside corners provide a nailing surface for wall-covering material. Several methods can be used to tie walls together and provide the nailing surfaces needed.

Install extra studs in the outside wall. Attach the partition to them

Insert blocking and

nailers between the regular studsUse blocking between the regular studs and attach patented back-up clips to support inside wall coverings at the inside corners.Slide77

Wall Framing

Openings for doors and windows are built large enough for the window or door to be plumbed and shimmed after installation. A 36” wide door is typically installed in a 38 ½” “Rough Opening”. An 80” high door is typically installed in a 83” R.O. R.O. sizes are typically shown on plansSlide78

Wall Framing

Walls are laid out by marking the openings (centerlines) and wall intersections (centerlines) first, and then indicating the opening edges. Then 16” (or 24”) lay out lines are drawn. Any full length studs which fall inside the opening become cripple studsSlide79

Wall Framing

Walls are held square using either wood let-in bracing, metal bracing, or structural sheathing. Choice depends on how the walls will be assembled and lifted

.Slide80

Wall Framing

When top wall is complete, ceiling joists are installed if the roof is built with rafters. If the roof is built with trusses, the truss bottom chord will serve as the ceiling framing.

Strongbacks

commonly used to keep ceiling joists aligned.Slide81

Module D9: Stairs

Function of the stairs:

Stairs provide access from one floor of a building to another, they are also used for

emergency escape

Functions: 1. Riser – encloses the space between two consecutive treads in a flight. It also gives support to the tread. 2. Tread – provides a platform for climbing the stair. 3. Headroom – the clear vertical height measured from the ceiling to the nosing of the step which provides unobstructed access from floor to floor. 4. Handrail – provides support to the user when climbing or descending the stair. 5. Balustrade – provides protection to the sides of the stair so persons do not fall off at a height. 6. Newel post – provides support for the handrail and the staircase. Slide82

Parts of a Timber StairsSlide83