THE STUDENTS’ INDUSTRIAL WORK EXPERIENCE

SCHEME (SIWES)

TECHNICAL REPORT DONE

AT

TICAL CONSTRUCTION LIMITED

ALONG SECRETARIATE ROAD, ARROMA ROUNDABOUT, AWKA.

SUBMITTED

BY

EMENZE UGOCHUKWU STANLEY

REG NO. 2007224736

DEPARTMENT OF CIVIL ENGINEERING

NNAMDI AZIKIWE UNIVERSITY AWKA

ANAMBRA STATE

IN

PARTIAL FULFILLMENT OF THE REQUIREMENT FOR

THE AWARD OF B.ENG DEGREE IN CIVIL ENGINEERING.

MARCH, 2011.

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INTRODUCTION

These involve the techniques and industry involved in the assembly

and erection of structures, primarily those used to provide shelter.

Building construction is an ancient human activity. It began with the purely

functional need for a controlled environment to moderate the effects of

climate. Constructed shelters were one means by which human beings were

able to adapt themselves to a wide variety of climates and become a global

species.

The first shelters were dwellings, but later other functions, such as

food storage and ceremony, were housed in separate buildings. Some

structures began to have symbolic as well as functional value, marking the

beginning of the distinction between architecture and building.

The history of building is marked by a number of trends. One is the

increasing durability of the materials used. Early building materials were

perishable, such as leaves, branches, and animal hides. Later, more durable

natural materials such as clay, stone, and timber and, finally, synthetic

materials such as brick, concrete, metals, and plastics were used. Another is

a quest for buildings of ever greater height and span; this was made possible

by the development of stronger materials and by knowledge of how

materials behave and how to exploit them to greater advantage. A third

major trend involves the degree of control exercised over the interior

environment of buildings: increasingly precise regulation of air temperature,

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light and sound levels, humidity, odours, air speed, and other factors that

affect human comfort has been possible. Yet another trend is the change in

energy available to the construction process, starting with human muscle

power and developing toward the powerful machinery used today.

The present state of building construction is complex. There is a wide range

of building products and systems which are aimed primarily at groups of

building types or markets. The design process for buildings is highly

organized and draws upon research establishments that study material

properties and performance, code officials who adopt and enforce safety

standards, and design professionals who determine user needs and design a

building to meet those needs. The construction process is also highly

organized; it includes the manufacturers of building products and systems,

the craftsmen who assemble them on the building site, the contractors who

employ and coordinate the work of the craftsmen, and consultants who

specialize in such aspects as construction management, quality control, and

insurance.

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CHAPTER ONE

BUILDING CONSTRUCTION AND MATERIALS

Building Construction are procedures involved in the erection of

various types of structures. They are techniques and industries involved in

the assembly and erection of structures, primarily those used to provide

shelter.

There are three phases involved in building construction, they include;

Site investigation

Design programming

Design development

Actual construction

Maintenance

Site investigations

A preliminary site investigation is part of the feasibility study, but once a

plan has been adopted a more extensive investigation is usually imperative.

Money spent in a rigorous study of ground and substructure may save large

sums later in remedial works or in changes made necessary in constructional

methods.

Since the load-bearing qualities and stability of the ground are such

important factors in any large-scale construction

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Design programming

The design of a building begins with its future user or owner, who has in

mind a perceived need for the structure, as well as a specific site and a

general idea of its projected cost. The user, or client, brings these facts to a

team of design professionals composed of architects and engineers, who

can develop from them a set of construction documents that define the

proposed building exactly and from which it can be constructed.

Building design professionals include those licensed by the state—such as

architects and structural, mechanical, and electrical engineers—who must

formally certify that the building they design will conform to all

governmental codes and regulations. Architects are the primary design

professionals; they orchestrate and direct the work of engineers, as well as

many other consultants in such specialized areas as lighting, acoustics, and

vertical transportation.

The design professionals draw upon a number of sources in preparing their

design. This includes the parts of physical theory that relate to building, such

as the elastic theory of structures and theories of light, electricity, and fluid

flow. There is a large compendium of information on the specific properties

of building materials that can be applied in mathematical models to reliably

project building performance. There is also a large body of data on criteria

for human comfort in such matters as thermal environment, lighting levels,

and sound levels that influence building design.

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In addition to general knowledge of building science, the design team

collects specific data related to the proposed building site. These include

topographic and boundary surveys, investigations of subsoil conditions for

foundation and water-exclusion design, and climate data and other local

elements.

Concurrently with the collection of the site data, the design team works with

the client to better define the often vague notions of building function into

more precise and concrete terms. These definitions are summarized in a

building space program, which gives a detailed written description of each

required space in terms of floor area, equipment, and functional

performance criteria. This document forms an agreement between the

client and the design team as to the expected building size and

performance.

Design development

The process by which building science, site data, and the building space

program are used by the design team is the art of building design. It is a

complex process involving the selection of standard building systems, and

their adaptation and integration, to produce a building that meets the

client's needs within the limitations of government regulations and market

standards. These systems have become divided into a number of clear

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sectors by the building type for which they are intended. The design process

involves the selection of systems for foundations, structure, atmosphere,

enclosure, space division, electrical distribution, water supply and drainage,

and other building functions. These systems are made from a limited range

of manufactured components but permit a wide range of variation in the

final product. Once the systems and components have been selected, the

design team prepares a set of contract documents, consisting of a written

text and conventionalized drawings, to describe completely the desired

building configuration in terms of the specified building systems and their

expected performance. When the contract documents have been

completed, the final costs of the building can usually be accurately

estimated and the construction process can begin.

Construction

Construction of a building is usually executed by a specialized construction

team; it is normally separate from the design team, although some large

organizations may combine both functions. The construction team is headed

by a coordinating organization, often called a general contractor, which

takes the primary responsibility for executing the building and signs a

contract to do so with the client. The cost of the contract is usually an

agreed lump sum, although cost-plus-fee contracts are sometimes used on

large projects for which construction begins before the contract documents

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are complete and the building scope is not fully defined. The general

contractor may do some of the actual work on the building in addition to its

coordinating role; the remainder of the work is done by a group of specialty

subcontractors who are under contract to the general contractor. Each

subcontractor provides and installs one or more of the building systems—

e.g., the structural or electrical system. The subcontractors in turn buy the

system components from the manufacturers. During the construction

process the design team continues to act as the owner's representative,

making sure that the executed building conforms to the contract documents

and that the systems and components meet the specified standards of

quality and performance.

Maintenance

The contractor maintains the works to the satisfaction of the consulting

engineer. Responsibility for maintenance extends to ancillary and temporary

works where these form part of the overall construction. After construction

a period of maintenance is undertaken by the contractor, and the payment

of the final installment of the contract price is held back until released by

the consulting engineer. Central and local government engineering and

public works departments are concerned primarily with maintenance, for

which they employ direct labour.

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CHAPTER 2

CONSTRUCTION PROCESSES

Processes involved in building construction may differ depending on

the size and purpose of the project. It may involve all or some of the

following processes;

Site preparation

Setting out operation

Excavation and foundation

The structure

Roofing

Installation of other building elements and finishes

SITE PREPARATION

This involves the initial clearing of the site to be worked on. This

may include activities like cutting of grasses, grubbing out of trees and

stumps, removal of unwanted existing structures, removal of

unwanted soil type, cutting and filling of areas necessary,

extermination of termites and ants. Site preparation can be done

using simple hand tools in the case of small projects while other

heavier machines can be used during heavy projects and

constructions. Among the typical hand tools used includes spades,

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shovels, cutlass, hoe, axe, chain saw while mechanical plants includes

graders, bulldozers and tractors.

SETTING OUT OPERATION

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CHAPTER TWO

ELEMENTS OF A BUILDING

The major elements of a building include the following:

Building loads

Foundation

The structure

The interior partitions

The exterior partitions and roofs

Environmental control

Communications and power systems

Vertical transportation systems

Water supply and waste disposal

Building Loads

The loads imposed on a building are classified as either “dead” or

“live.” Dead loads include the weight of the building itself and all major

items of fixed equipment. Dead loads always act directly downward, act

constantly, and are additive from the top of the building down. Live loads

include wind pressure, seismic forces, vibrations caused by machinery,

movable furniture, stored goods and equipment, occupants, and forces

caused by temperature changes. Live loads are temporary and can produce

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pulsing, vibratory, or impact stresses. In general, the design of a building

must accommodate all possible dead and live loads to prevent the building

from settling or collapsing and to prevent any permanent distortion,

excessive motion, discomfort to occupants, or rupture at any point.

Foundations

The foundation is the most important part of any engineering

structure which transmits the loads of the structure to the underlying soil.

The structural design of a building depends greatly on the nature of the soil

and underlying geologic conditions and modification by man of either of

these factors.

Types of Foundations

The most common types of foundation systems are classified as shallow and

deep. Shallow foundation systems are several feet below the bottom of the

building while deep foundations extend several dozen feet below the

building. The foundation chosen for any particular building depends on the

strength of the rock or soil, magnitude of structural loads, and depth of

groundwater level.

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Shallow foundations

Shallow foundations are those founded near to the finished ground

surface; generally where the founding depth (Df) is less than the width of the

footing and less than 3m. These are not strict rules, but merely guidelines:

basically, if surface loading or other surface conditions will affect the bearing

capacity of a foundation it is 'shallow'. Shallow foundations (sometimes

called 'spread footings') include pads ('isolated footings'), strip footings and

rafts.

Shallows foundations are used when surface soils are sufficiently strong and

stiff to support the imposed loads; they are generally unsuitable in weak or

highly compressible soils, such as poorly-compacted fill, peat, recent

lacustrine and alluvial deposits, etc. These include;

Pad foundations

Strip foundations

Raft foundations

Pad foundations

Pad foundations are used to support an individual point load such as that

due to a structural column. They may be circular, square or rectangular.

They usually consist of a block or slab of uniform thickness, but they may be

stepped or haunched if they are required to spread the load from a heavy

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column. Pad foundations are usually shallow, but deep pad foundations can

also be used.

Strip foundations

Strip foundations are used to support a line of loads, either

due to a load-bearing wall, or if a line of columns need

supporting where column positions are so close that

individual pad foundations would be inappropriate.

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Raft foundations

Raft foundations are used to spread the load from a structure over a large

area, normally the entire area of the structure. They are used when column

loads or other structural loads are close together and individual pad

foundations would interact.

A raft foundation normally consists of a concrete slab which extends over

the entire loaded area. It may be stiffened by ribs or beams incorporated

into the foundation.

Raft foundations have the advantage of reducing differential settlements as

the concrete slab resists differential movements between loading positions.

They are often needed on soft or loose soils with low bearing capacity as

they can spread the loads over a larger area.

Deep foundations

Deep foundations are those founding too deeply below the finished

ground surface for their base bearing capacity to be affected by surface

conditions, this is usually at depths >3 m below finished ground level. They

include piles, piers and caissons or compensated foundations using deep

basements and also deep pad or strip foundations. Deep foundations can be

used to transfer the loading to deeper, more competent strata at depth if

unsuitable soils are present near the surface. Deep foundations include;

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Piles are relatively long, slender members that transmit foundation loads

through soil strata of low bearing capacity to deeper soil or rock strata

having a high bearing capacity. They are used when for economic,

constructional or soil condition considerations it is desirable to transmit

loads to strata beyond the practical reach of shallow foundations. In

addition to supporting structures, piles are also used to anchor structures

against uplift forces and to assist structures in resisting lateral and

overturning forces.

Piers are foundations for carrying a heavy structural load which is

constructed insitu in a deep excavation.

Caissons are a form of deep foundation which are constructed above ground

level, then sunk to the required level by excavating or dredging material

from within the caisson.

Compensated foundations are deep foundations in which the relief of stress

due to excavation is approximately balanced by the applied stress due to the

foundation. The net stress applied is therefore very small. A compensated

foundation normally comprises a deep basement.

Piles

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Piles are often used because adequate bearing capacity cannot be found at

shallow enough depths to support the structural loads. It is important to

understand that piles get support from both end bearing and skin friction.

The proportion of carrying capacity generated by either end bearing or skin

friction depends on the soil conditions. Piles can be used to support various

different types of structural loads.

Types of pile

End bearing piles

Friction piles

Settlement reducing piles

Tension piles

Laterally loaded piles

Piles in fill

End bearing piles

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End bearing piles are those which terminate in hard, relatively impenetrable

material such as rock or very dense sand and gravel. They derive most of

their carrying capacity from the resistance of the stratum at the toe of the

piles

Friction piles

Friction piles obtain a greater part of their carrying capacity by skin friction

or adhesion. This tends to occur when piles do not reach an impenetrable

stratum but are driven for some distance into a penetrable soil. Their

carrying capacity is derived partly from end bearing and partly from skin

friction between the embedded surface of the soil and the surrounding soil.

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Tension piles

Structures such as tall chimneys, transmission towers and jetties can be

subject to large overturning moments and so piles are often used to resist

the resulting uplift forces at the foundations. In such cases the resulting

forces are transmitted to the soil along the embedded length of the pile. The

resisting force can be increased in the case of bored piles by under-reaming.

In the design of tension piles the effect of radial contraction of the pile must

be taken into account as this can cause about a 10% - 20% reduction in shaft

resistance.

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Laterally loaded piles

Almost all piled foundations are subjected to at least some degree of

horizontal loading. The magnitude of the loads in relation to the applied

vertical axial loading will generally be small and no additional design

calculations will normally be necessary. However, in the case of wharves and

jetties carrying the impact forces of berthing ships, piled foundations to

bridge piers, trestles to overhead cranes, tall chimneys and retaining walls,

the horizontal component is relatively large and may prove critical in design.

Traditionally piles have been installed at an angle to the vertical in such

cases, providing sufficient horizontal resistance by virtue of the component

of axial capacity of the pile which acts horizontally. However the capacity of

a vertical pile to resist loads applied normally to the axis, although

significantly smaller than the axial capacity of that pile, may be sufficient to

avoid the need for such 'raking' or 'battered' piles which are more expensive

to install. When designing piles to take lateral forces it is therefore

important to take this into account.

Piles in fill

Piles that pass through layers of moderately- to poorly-compacted fill will be

affected by negative skin friction, which produces a downward drag along

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the pile shaft and therefore an additional load on the pile. This occurs as the

fill consolidates under its own weight.

Factors influencing choice of pile

There are many factors that can affect the choice of a piled foundation. All

factors need to be considered and their relative importance taken into

account before reaching a final decision.

Location and type of structure

Ground conditions

Durability

Cost

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1. Location and type of structure

For structures over water, such as wharves and jetties, driven piles or driven

cast-in-place piles (in which the shell remains in place) are the most suitable.

On land the choice is not so straight forward. Driven cast-in-place types are

usually the cheapest for moderate loadings. However, it is often necessary

for piles to be installed without causing any significant ground heave or

vibrations because of their proximity to existing structures. In such cases,

the bored cast-in-place pile is the most suitable. For heavy structures

exerting large foundation loads, large-diameter bored piles are usually the

most economical. Jacked piles are suitable for underpinning existing

structures.

2. Ground conditions

Driven piles cannot be used economically in ground containing boulders or

in clays when ground heave would be detrimental. Similarly, bored piles

would not be suitable in loose water-bearing sand, and under-reamed bases

cannot be used in cohesionless soils since they are susceptible to collapse

before the concrete can be placed.

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3. Durability

This tends to affect the choice of material. For example, concrete piles are

usually used in marine conditions since steel piles are susceptible to

corrosion in such conditions and timber piles can be attacked by boring

mollusks. However, on land, concrete piles are not always the best choice,

especially where the soil contains sulphates or other harmful substances.

4. Cost

In coming to the final decision over the choice of pile, cost has considerable

importance. The overall cost of installing piles includes the actual cost of the

material, the times required for piling in the construction plan, test loading,

the cost of the engineer to oversee installation and loading and the cost of

organization and overheads incurred between the time of initial site

clearance and the time when construction of the superstructure can

proceed.

The Structure

The structural systems of buildings may vary depending on the type and

purpose of the building.

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