Building construction

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CONSTRUCTION 2010 i MAKERERE UNIVERSITY FACULTY OF TECHNOLOGY DEPARTMENT OF CONSTRUCTION ECONOMICS AND MANAGEMENT PROGRAM: BSc CONSTRUCTION MANAGEMENT ASSSIGNMENT: CONSTRUCTION MODULE REPORT NAME: KALULE ISAAC REGISTRATION No: 09/U/625 STUDENT No: 209000864 INSTRUCTOR: Mr. RWENDEIRE IVAN

description

Constructioon technology

Transcript of Building construction

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MAKERERE UNIVERSITY

FACULTY OF TECHNOLOGY

DEPARTMENT OF CONSTRUCTION ECONOMICS

AND MANAGEMENT

PROGRAM: BSc CONSTRUCTION MANAGEMENT

ASSSIGNMENT: CONSTRUCTION MODULE REPORT

NAME: KALULE ISAAC

REGISTRATION No: 09/U/625

STUDENT No: 209000864

INSTRUCTOR: Mr. RWENDEIRE IVAN

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DECLARATION

“I hereby declare that I have read this thesis and in my opinion this thesis is

Sufficient in terms of scope and quality.”

Signature: ……………………………………………….

Name of Supervisor:

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“I declare that this practical report entitle “CONSTRUCTION” is the result of my

own research except as cited in the references.”

Signature: ……………………………

Name: KALULE ISAAC

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ACKNOWLEDGEMENT

It is really a hard task for me to complete this study without the help from those

people around me.

I would like to express my gratitude of thanks to Mr. Rwendeire Ivan who spent

time to guide and help us patiently on what should be included in this report. I

wouldn‟t never been able to get through this without your advice.

Besides, I would like to thank my parents and family for their support and

encouragement. It is meaningful and helpful to me. Lastly thank you to all my

friends who willing to help me and giving a full concern to me especially during

the discussions we together, thank you very much.

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TABLE OF CONTENTS

TITLE PAGE

TITLE PAGE i

DECLARATION ii & iii

ACKNOLEDGEMENT iv

TABLE OF CONTENT vi

1.1 Objectives 1

1.2 Introduction 1

1.2.1 Applications of construction 1

1.3 Building Construction 2

1.31 Principal factors of construction

1.4 Design process

1.41Building team

1.5 site works and setting out 6

1.5.1 Clearing site 6

1.5.2 Hoarding 6

1.5.3 Leveling 6

1.5.4 Setting out 7

1.6 Sub structure 9

1.61 Foundations 9

1.7 Super Structure 14

1.7.1 Walls 14

1.7.1.1 Walling materials 14

1.7.1.2 Block and brick bonding 14

1.7.2 Beams columns and slabs 15

1.7.2.4 False work and form work 16

1.7.3 Roofs 19

1.8 Scaffolds 24

1.9 Services 29

1.9.1 Drainage systems 29

1.9.1.1 Types of drainage systems 29

1.9.2 Septic tank 31

1.9.3 Stabilization ponds 32

2.0 Water supply 33

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2.1Indirect water system 35

2.2 direct water supply 36

3.0 conclusion 38

References 38

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CONSTRUCTION

1.1 OBJECTIVES

To create an understanding of the basic component of a building,

documentation and materials quality and selection.

To explain the main components of a building structure, major sections,

elements and materials.

To understand the roles played by of the different parties involved in the

execution of a given construction projection.

1.2 Introduction

Construction is the process which involves assembling different structural

element in order to come with a stable structure backed up with the proper

planning, execution, and control of construction operations of a given projects .

1.2.1 Applications of construction

In civil engineering construction can be witnessed on a number of project

which among others include the following;

Highways/ roads/ bridges

Building construction

Dams

Railway lines

Retaining structures

Water resource engineering facilities

Airport runways/ air fields

Recreation facilities

1.3 BUILDING CONSTRUCTION

Building construction is a process which involves enclosing space (hoarding)

where construction of a given structure is going to be executed, in order to

create a favourable internal working environment, assembling both structural

and architectural elements while following the relevant documents (structural

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drawings, architectural drawings etc) and sustaining the structure throughout

its working life time by regular maintenance.

1.3.1 PRINCIPAL FACTORS OF BUILDING CONSTRUCTION

Capital

This is measure of the accumulated financial strength of an individual, firm,

or nation, created by sacrificing present consumption in favor of investment

to generate future returns above investment costs. Capital plays different

roles in the execution of the proposed project which among others include

the following; payment for both structural element (like reinforcing steel

bars, aggregates, cement etc) and architectural element (like tiles, fitting,

paint etc), payment for service offered by the different parties (like

engineers, surveyors, casual labourers etc) involved in the execution of the

proposed project

Land

Land refers to the space or ground on which the proposed project is to be

executed whose ownership is clearly shown by legal document like land

titles.

In Uganda there are mainly four categories of land ownership viz;

i) Customary land

Customary land is land which is owned by indigenous communities

and administered in accordance with their customs, as opposed to

statutory tenure usually introduced during the colonial periods.

Common ownership is one form of customary land ownership.

ii) Leasehold land

This is land which is owned by the government or a landowner and

then leased to a tenant for a fixed period of time.

iii) Milo land

This is form tenure where land ownership is in the hands of tribal or

clan leaders and under this category land is administered by the local

land boards.

iv) Freehold land

Here ownership is in perpetuity, and a certificate of title is issued.

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Labour

This refers to human. Labour may either be skilled (this constitutes technical

effort forwarded towards the execution of the proposed project by engineers,

quantity surveyors, land surveyors, etc) and unskilled (this constitutes casual

and physical effort forwarded towards the execution of the proposed project

mainly by foremen, clerks of works, porters etc)

Other factors which affect building construction among others include:

Intended purpose of the proposed building, material availability, topography,

available infrastructure, security, space etc.

1.4 DESIGN PROCESS

The design process includes the active and continuing participation of users, code

officials, building technologists, cost consultants, civil engineers, mechanical and

electrical engineers, structural engineers, specifications specialists, and consultants

from many specialized fields. The illustration in figure 1below shows a simplified

layout of the design process:

Figure 1 (adapted from: /www.mfe.govt.nz/publications/sus-dev/integrated-whole-

building-design-guidelines/html/images/figure1.gif)

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Preparation for the project can be led by many players but generally comes

from the user/client who identifies the need for building on the basis of

quantifiable requirements for space and budgetary capacity to undertake the

activity. A needs assessment often accompanies this planning activity—it

can describe existing space use; develop realistic estimates of requirements,

both spatial and technical; and arrive at a space program around which

Once the Pre-design activities are complete, the architect or other prime

consultant, in consultation with his or her team of sub-consultants, may

produce initial graphic suggestions for the project or portions of it. Such

suggestions are meant to stimulate thought and discussion, not necessarily to

describe the final outcome.

Gradually a design emerges which embodies the interests and requirements

of all participants while also meeting the overall area requirements which the

project budget will have established during Pre-Design activities. The

resulting Schematic Designs produced at this stage show site location and

organization, general building shape, space allocation, and an outline

specification which makes an initial list of components and systems to be

designed and/or specified for the final result.

It is often useful to have a cost estimate performed by a professional cost

estimator called a quantity surveyor at this point. Cost estimations is done by

preparation of a bill of quantities. They are prepared by a “taking off”

process in which the cost of a building or other structure is estimated from

measurements in the architect's drawings. These are used to create a cost

estimate such as in regard to the square area in meters of walls and roofs, the

numbers of doors and windows, and systems as heating, plumbing and

electrics. An example of a bill of quantity is as illustrated in figure 2 :

The approved definitive design documents are developed into

comprehensive construction drawings and specifications that are submitted

to the concerned authorities for endorsement or approval of the proposed

project. The approval is effected by issuing of a building permit.

After approval, a cost estimate (bill of quantities) can be used for the

selection process of the building company or contractor a process known as

tendering or bidding. Tendering may either be open or restricted

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i) Open tendering: Bidding process that is open to all qualified bidders and

where the sealed bids are opened usually in public for scrutiny and are

chosen on the basis of price and quality. Also called competitive tender or

public tender.

ii) Restricted tendering or bidding: Invitation to bid (ITB) sent only to

selected contractors who have been pre-qualified through a screening

process.

After the general contractor is selected construction commences and it is

done with the whole of building team collectively participating.

Figure 2 (adapted from; www.ajk.ie/pages/products/images/clip_image006.jpg)

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1.4.1 THE BUILDING TEAM

Building is essentially a team effort in which each member has an important role to

play. Figure 3 shows the organization structure of a typical team;

BUILDING OWNER

ARCHITECT

CONTRACTOR CLERKS OF WORKS QUANTITY SURVEYOR

CONSTRUCTION MANAGERS SURVEYORS ESTIMATORS BUYER ADMINISTRATOR ENGINEERS SITE AGENT

GENERAL FOREMAN COSTING

TRADES FOREMAN ACCOUNTING

OPERATIIVES OFFICE STAFF

Figure 3

1.5 SITE WORKS AND SETTING OUT

When the site has been taken over, the task of preparing for and setting out the

building can be commenced. These operations can be grouped under four

categories viz:

1. Clearing site

2. Hoarding site

3. Establishing levels

4. Setting out the building

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1.5.1 Clearing site

This may involve demolition of existing buildings, the grubbing out of bushes

and trees or existing tree stumps and removal of soil to reduced levels.

1.5.2 Hoarding

Hording involves enclosing the site using iron sheets of inferior gauge or

fencing using wire mesh. The law requires that building sites should be hoarded

before construction commences. The hoarding needs to be accurately

constructed in order to provide protection to the public, resist impact damages,

resistance anticipated by wind pressure and adequately lit at night.

Figure 4 shows the typical hoarding details.

1.5.3 Leveling

Levels can be established using the following methods;

1. Cut and fill

2. Cut

3. Fill

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Figure 4 (adapted from construction technology handbook by R. chudley an R. Greeno 5th

edition page 86)

1.5.4 Setting out

This task is usually undertaken once the site has been hoarded, cleared of any

debris or obstruction and any reduced level excavation works are finished.

Accurate setting out is of paramount importance and should therefore only be

carried out by competent persons and all their work thoroughly checked. This

involves setting out the building outline followed by setting out trenches

1.5.4.1 Setting out the building outline

The first task in setting out a building out line is to establish a baseline to

which all the setting out can be related. Usually the longest side of the

building is chosen for convenience. Figure 5 illustrates this.

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Figure 5 (adapted from construction technology handbook by R. chudley 8th

edition page111)

1.5.4.2 Setting out trenches

The objectives of this task are:

To establish the excavation size, shape and direction and

To establish the width and position of the wall.

The outlines of the building will have been set out and using this out line,

profile boards can be setup to control the position, width and possible depth

of the proposed trenches. Profile boards should be set up at least

2.000metres clear of the trench position so as not to obstruct the excavation

work. Figure 6 illustrates this.

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Figure 6 (adapted from construction technology handbook by R. chudley 8th

edition page112)

1.6 SUB-STRCTURE: FOUNDATIONS

Sub structure is the portion or part of the building below the ground level. It

normally includes foundations and the ground floor slab. The purpose of the

sub structure is to firmly anchor the building to the ground, transfer and

distribute all the loading to the ground.

1.6.1 FOUNDATIONS

The function of any foundation is to safely sustain and transmit to the

ground on which it rests the combined dead, imposed and wind loads in such

a manner so as not to cause settlement or other movements which may

impair the stability and/ or damage to any part of the building.

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1.6.1.1 FOUNDATION TYPES

There are four types of foundation types namely: strip, pad, raft, and pile. These

foundation types are either used individually or in combination on a building

project.

STRIP FOUNDATION

This type involves construction of a plinth wall on mass concrete along the

trenches. The trenches are normally dug where actual walls of the super structure

are erected. The details of strip foundations are shown in figure 7.

Application

These are more suitable for most subsoils and light structural loading such as those

encountered in low to medium rise domestic dwellings where mass concrete can be

used.

Figure 7 (adapted from construction technology handbook by R. chudley an R. Greeno 6th

edition page 208)

PAD FOUNDATION

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These are foundations with reinforced concrete bases and columns. The columns

are usually rectangular or circular in shape. Pad foundations are either combined

(with one column fixed on one base) or combined (with more than one column

fixed on one base) Figure 8 gives details of both isolated and combined pad

foundation

Application

Pad foundations a usually applicable in storied building where the structure is

susceptible to heavy loads.

Figure 8 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno

page 191)

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PILE FOUNDATION

These can be defined as a series of columns constructed or inserted into the ground

to transmit the load(s) of a structure to a lower level of subsoil.

Application

Piled foundations can be used when suitable foundation conditions are not present

at or near ground level making the use of deep traditional foundations uneconomic.

The lack of suitable foundation conditions may be caused by:-

1. Natural low bearing capacity of subsoil.

2. High water table giving rise to high permanent dewatering costs.

3. Presence of layers of highly compressible subsoils such as peat and recently

placed filling materials which have not sufficiently consolidated.

4. Subsoils which may be subject to moisture movement or plastic

Classification of foundations

Pile foundations can either be friction or end bearing depending on the way they

transmit the loads to the sub soil. Figure 9 show detailed information of both

friction and end bearing foundations.

Figure 9 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno

page 205)

RAFT FOUNDATION

These are used to spread the load of the superstructure over a large base to reduce

the load per unit area being imposed on the ground. Figure 9 illustrates typical

details of a raft foundation.

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Figure 9 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno

page 203)

Application

This is particularly applicable where low bearing capacity soils are encountered

and where individual column loads are heavy.

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1.7 SUPER STRUCTURE

Sub structure is the portion or part of the building above the ground level. It

normally includes the walling, windows, doors, beams, slabs, columns, and the

roof.

1.7.1 WALLS

These are structures of bricks, stones, or blocks used to enclose (external walls),

divide (partition and party walls) or support a building. Walls can be constructed

from different materials and using different bonding for the case of brick and block

walls

1.7.1.1 WALLING MATERIALS

The different materials that can be used in the construction of a walling unit among

others include the following:

Bricks

Mortar

Concrete

Steel

Mud and wattle

Grass and wattle

Timber

Stones

1.7.1.2 BLOCK AND BRICK BONDING

Bonding refers to an arrangement of bricks or blocks in a wall, column or pier laid

to a set pattern to maintain an adequate lap.

Purposes of Brick Bonding

1. Obtain maximum strength whilst distributing the loads to be carried

throughout the wall, column or pier.

2. Ensure lateral stability and resistance to side thrusts.

3. Create an acceptable appearance.

FORMS OF BONDING

There are mainly four forms of brick bonding used in construction and these

include the following:

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Stretcher bond; this involves laying all courses of stretcher. Figure 10

illustrates this form of bonding.

Figure 10 (adapted from: /sites.google.com/site/building4today/_/rsrc/1267550154565/B4T-

Brick-Stretcher-custom-size-364-264.jpg)

Header; this involves laying all courses of header. Figure 11 illustrates this form

of bonding.

Figure 11 (Adapted from;

/sketchup.google.com/3dwarehouse/details?mid=be22f126cbf9071afb2ff900498c5c8d)

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English Bond; formed by laying alternate courses of stretchers and headers

it is one of the strongest bonds but it will require more facing bricks than

other bonds. Figure 12 illustrates this form of bonding.

Figure 12 (Adapted from:/sites.google.com/site/building4today/_/rsrc/1267550153936/B4T-

Brick-English-custom-size-406-307.jpg)

Flemish Bond; formed by laying headers and stretchers alternately in each

course. Not as strong as English bond but is considered to be aesthetically

superior uses less facing bricks. Figure 13 illustrates this form of bonding.

. Figure 13

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1.7.2 BEAMS, COLUMNS AND SLABS

1.7.2.1 BEAMS

These are horizontal load bearing members which are classified as either main

beams which transmit floor and secondary beam loads to the columns or secondary

beams which transmit floor loads to the main beams. Figure 14 illustrates typical

details of beam.

1.7.2.2 COLUMNS

These are the vertical load bearing members of the structural frame which

transmits the beam loads down to the foundations. They are usually constructed in

storey heights and therefore the reinforcement must be lapped to provide structural

continuity. Figure 15 illustrates typical details of column.

1.7.2.3 SLABS

Reinforced concrete slabs are mainly of two type namely hollow (which comprise

of maxpans commonly known as “kajjansi”) and solid (which are made from

concrete and reinforcements)

Figure 16 illustrates typical details of rectangular and square solid slab.

1.7.2.4 FORM AND FALSE WORKS

Concrete when first mixed is a fluid and therefore to form any concrete member

the wet concrete must be placed in a suitable mould to attain the desired shape, size

and position as it sets. These moulds are called formwork.

Formwork is supported by temporary structures known as falsework.

Falsework refers to temporary structures or elements used to support formwork in

order to hold the concrete components in place until it has sufficiently advanced to

support its self. Figures 17 and 18 illustrate typical details of a beam and column

formworks respectively.

1.7.3 FINISHES

Finishes include all final surfaces provided to roofs internal and external walls,

floors, stairs and ceilings to render the structure habitable as per the needs of the

client. The figure below illustrates details of tile floor finish

Common finishes include:

Plastering

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Painting

Tiling

Terrazzo

Asphalt or bitumen

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Figure 14 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 380)

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Figure 15 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 384)

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Figure 16 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 377)

Figure 17 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 395)

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Figure 18 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 396)

1.7.3 ROOF

Roofs can be classified as being either;

1. Flat: pitch from 0o to 10

o. Figure 19 below illustrates typical details of a flat

roof. or

2. Pitched: pitch over 10o. Pitched roofs can further be sub-divided into the

following forms

Lean to roofs

Monopitch roofs

Gamble end roofs

Hipped end roofs

Mansard or gambrel roofs

Figure 20 and 21 below illustrates typical details of these forms of pitched roofs. or

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Figure 19 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 435)

ROOF STRUCTURE

A roof is in a very exposed situation and must therefore be designed and

constructed in such a manner as to:-

1. Safely resist all imposed loadings such as snow and wind.

2. Be capable of accommodating thermal and moisture movements.

3. Be durable so as to give a satisfactory performance and reduce maintenance

to a minimum.

ROOF TRUSSES

These are triangulated plane roof frames designed to give clear spans between the

external supporting walls. They are usually prefabricated or partially prefabricated

off site and are fixed at 1800mm centres to support purlins which accept loads

from the infill rafters. Figure 22 below illustrates typical details of a roof truss.

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Figure 20 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 436)

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Figure 21 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 437)

ROOF COVERING MATERIALS

These among others include the following;

Iron sheets

Tiles

Slates

Timber

Grass

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Figure 22 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 441)

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1.8 SCAFFOLDS

These are temporary working platforms erected around the perimeter of a building

or structure to provide a safe working place at a convenient height. They are

usually required when the working height or level is 1500mm or more above the

ground level.

1.8.1 TYPES OF SCAFFOLDS

These include among others the following.

1. Putlog Scaffolds; these are scaffolds which have an outer row of standards

joined together by ledgers which in turn support the transverse putlogs

which are built into the bed joints or perpends as the work proceeds, they are

therefore only suitable for new work in bricks or blocks. Figure 23 shows

typical details of a putlog scaffold

2. Independent Scaffolds; these are scaffolds which have two rows of

standards each row joined together with ledgers which in turn support the

transverse transoms. The scaffold is erected clear of the existing or proposed

building but is tied to the building or structure at suitable intervals. Figure 24

shows typical details of an independent scaffold.

3. Mobile Scaffolds; otherwise known as mobile tower scaffolds. They can be

assembled from pre-formed framing components or from standard scaffold

tube and fittings. They can be easily transferred from on part of the building

to another due to presence of caster wheels at its bottom. Figure 25 shows

typical details of a mobile scaffold.

4. Truss-out Scaffold; this is a form of independent tied scaffold used where it

is impracticable, undesirable or uneconomic to build a scaffold from ground

level. The supporting scaffold structure is known as the truss-out Figure 26

shows typical details of a truss out scaffold.

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Figure 23 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 122)

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Figure 24 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 123)

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Figure 25 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 127)

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Figure 26 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 132)

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1.9 SERVICES

1.9.1 DRAINAGE SYSTEMS

Drains; these can be defined as a means of conveying surface water or foul water

below ground level.

Sewers; these have the same functions as drains but collect the discharge from a

number of drains and convey it to the final outfall.

1.9.1.1 TYPES OF DRAINGE SYSTEMS

There are main two types of drainage systems namely:

Combined and separate drainage systems.

1. SEPARATE DRAINAGE SYSTEM

This is the most common drainage system in use where the surface water discharge

is conveyed in separate drains and sewers to that of foul water discharges and

therefore receives no treatment before the final outfall. Figure 27 below illustrates

this type of drainage system.

Figure 27 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 132)

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2. COMBINED DRAINAGE SYSTEM

This is the simplest and least expensive system to design and all forms of discharge

are conveyed in the same sewer. Figure 28 below illustrates this type of drainage

system.

DISADVANTAGE

The whole effluent must be treated unless a sea outfall is used to discharge

the untreated effluent.

Figure 28 (adapted from construction technology handbook by R. chudley and R. Greeno 6th

edition page 661)

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1.9.2 SEPTIC TANKS

How it works?

The septic tank system work by separates wastewater to separate into layers. The

bacteria present in the tanks decomposes the solid wastes that have settled to the

bottom of the tank thereby transforming most of the wastes in solids and gases.

The outflow pipe in the tank drain out the access liquid in the drainage system. The

outflow, through a series of subsurface pipes is distributed throughout the drain

field. Here effluent undergoes final treatment as the soil absorbs and filters the

liquid whereas rest of the materials is broke down by the microbes. Figure 29

below illustrate the plan and section of a septic tank.

Figure 29 (adapted from google.com/images/septic tank)

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1.9.3 STABILIZATION PONDS

Categorization Of Stablisation Pond

Stablisation or stabilization pond can be categorized as follows;

Aerobic Ponds

An aerobic pond throughout its entire depth has varying concentration of oxygen.

Anaerobic Pond

Anaerobic pond is devoid of any oxygen except in the top at the air liquid

interface.

Facultative Pond

Facultative pond is a combination of both aerobic and anaerobic pond. That is, in

its top zone it is aerobic whereas it is anaerobic at its lower zone

The amount of oxygen present in the pond depends upon the following factors:

Temperature

Organic loading

Sunlight

Maturation ponds

Maturation ponds are the ponds that receive effluent from a facultative pond. They

are shallow, with less vertical stratification and are well oxygenated.

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2.0 WATER SUPPLY

An adequate supply of cold water of drinking quality should be provided to every

residential building and a drinking water tap installed within the building. The

installation should be designed to prevent waste, undue consumption, misuse,

contamination of general supply, be protected against corrosion and frost damage

and be accessible for maintenance activities. Figures 30 and 31 show a typical

layout of a domestic water supply.

Figure 30 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 660)

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Figure 31 (Adapted from: building construction handbook 6th edition by R. Chudley an R.

Greeno page 661)

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2.1 INDIRECT WATER SUPPLY

An indirect water supply system is the most common type found in modern houses.

The mains water comes in via a rising main and directly feeds at least one cold tap

at the kitchen sink with „potable‟ water (i.e. water which is fit for drinking,

cooking etc) and may also feed a washing machine, a shower and an outside tap

etc. The rising main also feeds a storage tank at a high point in the building from

where the water is fed to all the other taps etc using gravity. Figure 32 illustrates

this form of drainage

Figure 32 (Adapted from; /www.practicaldiy.com/plumbing/water-supply/indirect-

water-supply.php)

The items identified in the illustration above (NOTE that the central heating has

been omitted for clarity) of an indirect water supply are:

1. Water company stopcock

2. Householder‟s stopcock.

3. Draincock

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4. Storage tank with a ballcock float valve to control the water stored

5. Gate valve which can isolate the cold water feed to the hot water tank.

6. Gate valve which can isolate the cold water to the WC and taps etc.

7. Hot water cylinder.

8. Gate valve which can isolate the hot water to the taps.

9. Storage tank overflow pipe

10. WC overflow pipe

11. Inline valves to isolate water feeds to washing machine or dishwasher etc.

Advantages of an indirect water supply

It does overcome the problem of furring, therefore suitable for hard water

areas.

It reduces the risk of back syphonage and hence limiting contamination.

It provides a reserve of water should the mains supply fail or be cut off.

Disadvantages of an indirect water supply

This system requires more pipework than the direct system

2.2 DIRECT WATER SUPPLY

A direct water supply system is one where the raising main feeds directly the cold

water taps and a multi point water heater.

The mains water comes in via a rising main and directly feeds all the cold taps and

a multi point water heater - so all the taps and other water feeds are at mains water

pressure. Figure 33 illustrates this form of drainage

Advantages of a direct water supply

The main advantage is that drinking water is available from all cold water

outlets.

Disadvantages of a direct water supply

These systems are suitable only for areas with high level reservoirs with a

good supply and pressure.

Lack of reserve in case of supply cut off.

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CONSTRUCTION 2010

40

Risk of back syphonage due to negative mains pressure and a risk of reduced

pressure during peak demand periods.

Figure 33 (adapted from /www.practicaldiy.com/plumbing/water-supply/direct-

water-supply.php)

The items identified in the illustration above of a direct water supply are:

1. Water company stopcock

2. Householders stopcock

3. Draincock.

4. Stopcock.

5. Gate valve which can isolate the cold water feed to the multi point water

heater.

6. Gate valve which can isolate the hot water from the multi point water heater

to the taps etc.

7. Multi water heater.

8. Inline valves to isolate water feeds to washing machine or dishwasher etc.

9. WC overflow pipe.

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3.0 Conclusion

During the four days of the practical part of this module different aspects with

in this scope of construction have been undertaken in and have yielded a

positive impact on my career development within the field of building

construction.

References

Construction technology hand books by R. Chudley and R. Greeno:

Editions 5th

,6th

, and 8th

www.practicaldiy.com/plumbing/water-supply/direct-water-supply.php

www.practicaldiy.com/plumbing/water-supply/indirect-water-supply.php

www.mfe.govt.nz/publications/sus-dev/integrated-whole-building-

design-guidelines/html/images/figure1.gif

www.wbdg.org/design/engage_process.php

Building technology hand book R. Chudley and R. Greeno 8th

edition