ABSTRACT
Investigation
into the causes, effects and prevention of crack in building, cracks this is a
kind of defects that occur into building structure which rendered building
unsightly and reduces building stabilities. Cracks may be of structural failure
or non-structural problem which may act slightly, moderate or several. They are
save or dangerous depending on the size and characteristics of each i.e.
0-3-1.00, 1-2, 2-5,5-15 and 15-25 (mm)
respectively survey of building were made in some selected area in Ilorin west
L.G.A Ilorin, were aerial photographs were taken, site investigation were made
in some selected areas. Cracks in building could be as a result of use of poor
materials, inappropriate mix ratio, poor workmanship, lack of soil test,
foundation settlement, poor supervision, environmental problems faulty
construction, faulty design and overloading, non-structural crack are mostly
due to internally induced stresses in building but may look unsightly or may
create an impression of instability or faulty work in some situation due to
penetration of moisture through them, non structural cracks may spoil the
internal finishing which thus adding to the cost of maintenance or corrode the
reinforcement thereby adversely affecting the stability of the structure in
long run e.g vertical crack in a long compound wall due to shrinkage or thermal
movement. Crack may appreciably vary in width from thin hair crack barely
visible to naked eye to gaping crack depending upon the crack width,a crack are
classified. Research shows that some of the problem of crack in Ilorin west
here are due to lack of maintenance and negligence i.e allowing vegetative
growth near structures which will be treating the structure, allowing
unnecessary water to lodge at the base of structure. All these problem could be
control by adequate maintenance professional advise and involvement in all
project, been it new construction or renovation and vegetation should be
control not only for constructional problem but heath wise, security conscious
and social befitting.
TABLE OF
CONTENTS
Abstract
Table of Contents
CHAPTER ONE
1.0 Introduction 1
1.2 Statement of the Problem 3
1.3 Objectives of the study 4
1.4 Justification 4
1.5 Scope of the Study 5
1.6 Methodology 5
1.7 Definition
of Terms and Full Meanings 5
CHAPTER
TWO
2.1 Cracks Recording and Measurement 8
2.2 Condition for Crack in Building 9
2.3 Causes of Cracks in Building Structure 10
2.4 Effects of cracks on Building Structure. 16
2.5 Remedial measure 16
2.6 Some Literature Review Pictures 17
CHAPTER THREE
3.1 Introduction 22
3.2 Methodology of Data Collection 22
3.3 Data Collection In Zone A 35
CHAPTER FOUR
ANALYSIS AND INTERPRETATION
OF DATA COLLECTED
4.1 Introduction
41
4.2 Analysis
and Interpretation Of Data Collected In Zone A 41
CHAPTER
FIVE
5.0 Conclusion 48
5.1 Recommendation 48
References
51
CHAPTER ONE
10 INTRODUCTION
Occurrence
of various cracks patterns in the building during construction, and after
completion when it is subjected to super imposed load or during the service
life, is a common phenomena’s. A building component develops cracks whenever
the stress in the component exceeds it’s strength. Stress in the building
component could be caused by externally applied forces, such as dead, live,
wind and seismic loads, foundation settlement e.t.c or it could be induced
internally due to thermal movement, moisture changes elastic deformation,
chemical reaction e.t.c
Cracks
in building could be broadly classified into two, as structural and
non-structural cracks.
Structural Cracks: These occur due to incorrect design, faulty construction or
overloading and these may endanger the safety of the building eg extensive
cracking of an RCC beam (rein force concrete course)
Non-Structural
Cracks: These are mostly due to internally induced stresses in building but may
look unsightly, or may create an impression of faulty work or may give a
feeling of instability in some situation due to penetration of moisture through
them, non-structural cracks may spoil the internal finishes thus adding to the
cost of maintenance, or corrode the reinforcement, thereby adversely affecting
the stability of the structure in long run e.g vertical crack in a long
compound wall due to shrinkage or thermal movement.
Cracks
may appreciably vary in width from thin hair crack barely visible to naked eye
to gaping crack. Depending upon the crack width crack are classified as.
(a) Thin
Crack — less than 1 mm in width
(b)
Medium Crack — 1 to 2mm in width
(c) Wide
Crack — more than 2mm in width
(d)
Crazing — Occurrence of closely fine cracks at the surface of a material these
is called crazing.
Cracks
may be of uniform width through out or may be narrow at one end gradually
widening at the other end. Cracks may be straight, toothed, stepped, map
pattern or random type and may be vertical, horizontal or diagonal.
Cracks
may be only surface and extend to more than one layer of materials. Cracks due
to different causes have varying characteristics and by the careful
observations of these characteristics, one can diagnose the causes of cracking
for adopting the appropriate reduced measures. Small magnitude causing tension
and shear stresses can lead to cracking. Internal stress are induced in the
building component on account of thermal movements, moisture change, elastic
deformation, chemical reaction etc.
All
these phenomenon causes dimensional changes in the building components, and
whenever this movement is restraint due to interconnectivity of various member,
resistance between the different layers of the components etc. stresses are
induced and whenever these stresses (tensile or shear) exceed the strength of
material cracks occurs.
Depending
upon the cause and certain physical properties of building materials, these
cracks may be wide, but further apart or may be thin but more closely space. As
a general rule, thin cracks even though closely spaced and greater in number,
are 1ess damaging to the structures and are not so objectionable from aesthetic
to the structure and other consideration as fewer number of wider cracks.
2.0 STATEMENT
OF THE PROBLEM
The
statement of the problem can as well be the causes of crack in building. Which
are as stated below
For the
structural cracks
•
Incorrect design
• Faulty
construction
•
Overloading
Cracking
of an RCC beam which can lead to extensive cracking of RCC beam which may
endanger the building safety.
Non-structural
cracks involved
•
Moisture change
•
Thermal movement
•
Elastic deformation
• Creep
•
Chemical reaction
•
Foundation movement and settlement of soil
• Growth
of vegetation
Those
element are mostly due to internally induced stresses in building materials and
do not endanger safety of a building but may look unsightly, or may create an
impression of faulty work or may give a feeling of instability in some
situation due to penetration of moisture through them. Non-structural cracks
may spoil the internal finishes thus adding to the cost of maintenance, or
corrode the reinforcement thereby adversely affecting the stability of the
structure in the long run e.g vertical crack in a long compound wall due to
shrinkage or thermal movement.
AIM The aim
of this project research is to investigate into the causes, effects and
prevention of cracks in building.
OBJECTIVES OF THE STUDY
1. To determine the various type of cracks that occur in
building.
2. To know the behaviours and effect of each types of cracks in
building.
3. To be able to prevent each types of cracks in building.
4. To be able to know forms of cracks that occurs in building.
5. To create a solution or remedies to an existing cracks in
building.
6. To know the behaviours of some constructional materials which
could lead to crack in building and suggestion of preventive measure.
7. To know the preparation measure to put in place in
construction site so as to prevent the effect of moisture changes, thermal
movement, chemical reaction, foundation movement, settlement of soil and growth
of vegetation around the site.
JUSTIFICATION
This
project will assist building industry in solving the problems of cracks in building
both structurally and non-structurally and know how to classified and control
each crack into their respective forms and types. i.e structural and non
structural, thin, medium, wide or crazing.
SCOPE OF THE STUDY
This
project is base on crack in building and due to time constraints, this study is
limited to causes, effect and prevention of crack in building so as to
prevent the occurrence of cracks and solution to the existing difference,
types, and forms of cracks in building.
METHODOLOGY
So as to
investigate into the causes. effect, and preventions of cracks in building the
proposed methodology to be use in this research are a follows.
1.
Reviewing
of literatures, and other related articles materials in line with this
research.
2.
Pictures
and photograph of section where cracks occur in building will be taken for
examination and correction.
DEFINITION OF TERMS AND FULL MEANINGS
1.
RCC-reinforce
concrete course