PRERACE
Practical Training (PT) is the one part of the four year B.Sc. (Eng.)
degree course offered by the college of Engineering and Technology (CoET) at
the University of Dar se Salaam. The Practical Training program takes duration
of eight (8) weeks and it is conducted after the second semester of each
academic year. The PT implements the theory taught at the college and the
practices performed during workshop sessions. The PT has the following main
goals;
·
To provide knowledge of materials,
processes and human relations
·
To train the students skills in using
equipment’s and tools
·
To develop abilities of planning,
organizing and communicating
·
To foster attitudes of awareness and
respect for work and of thinking in terms of cost and efficiency.
·
Also provide the reality to those
structure leant by students in the class to that on the site.
·
Interaction with other construction
members at the site whom will work with after completion of the university.
Generally; The Practical Training program provides an opportunity for
the students to relate theory and practice. It offers training in a real life
that can’t be simulated in lecture rooms or departmental workshops. Thus,
besides being productive, the students can learn about the problems they
encounter in their future focus enabling them conduct objective
assessments of the courses being offered
in their undergraduate studies and therefore choosing their options sensibly.
None can thus have Engineering professional without Practical Training. PT is
therefore a bridge (connection) of one’s professional between the Engineering
Training Institutes (colleges) and the construction firms (companies).
ACKNOWLEDGEMENT.
With genuine humility and much respect I thank the
almighty God for his endless love and mercy that he provides to me always in my
life and for the strength that he gave me during the period of practical
training.
It is with profound enchantment that I extend my
heartfelt gratitude to the following people
My
train officer Eng. SANCHO RWANDALLA
Site
foreman Mr. IPALALA
Academic
supervisor
Their contribution in my practical training is
invaluable, reminiscent and hence unforgettable
I would also like to thank all staffs of WESTERN
ENGINEERING LIMITED for the cooperation they have given me during my practical
training in their company
May God Bless You All
INTRODUCTION
GENERAL INFORMATION OF
THE COMPANY
WESTERN ENGINEERS LIMITED (W.E.L)
is a multidisciplinary Local Construction company, founded and registered in
Tanzania with Engineer’s Registration Board (ERB) in 1998 as Local Engineering
Consulting Firm. NCL is also a member of the Association of Consulting
Engineers (Tanzania) (ACET); the association is affiliated to FIDIC.The firm is wholly owned by ENG SAMWEL RWANDALLA and is also legally registered under the Companies Ordinance (Cap. 212) and currently operating through its office located in Arusha city center, located at OTTU offices complex.
Vision
WEL has the vision of being the Best Engineering Company to all of its Clients. To attain its vision and maintain it, the company has a set of nine core values which are:-
WEL has the vision of being the Best Engineering Company to all of its Clients. To attain its vision and maintain it, the company has a set of nine core values which are:-
- Client's Satisfaction
- Flexibility
- Openness and Transparency
- Team work
- Ethics Integrity and Professional conduct
- Best quality in construction
- Affordability
- External region branches expansion
- Employment opportunity availability
Missions
·
To exceed Client's expectations by
providing quality services within the given time frame work.
·
Also high efficiency in construction
and reaching the contemporary world standards.
·
The company also aims at conserving
the environment and creating the harmless atmosphere for the beneficiaries of
the projects conducted.
These
missions have always been possible due to the pre mentioned core values the
company has. It is these missions that are taking the company to the fore front
of multi-disciplinary engineering projects and management practices.
PROJECT SUMMARY
I conducted my practical training at WESTERN ENGINEERING LTD
in Arusha and completed it successfully in all eight weeks. My practical
training started on 2th July 2015 and end up on 17th august 2015. The tasks
which I mainly performed during my practical training were:
·
Slab work
·
Column works
·
Concreting
·
Formwork
·
Steel works
·
Operation of tools, machinery and equipments
PROJECT LOCATION
The project was located at Arusha district along corner
Nairobi road.it is 4km from Arusha bus station, it is at place called Osterbay
PROJECT PURPOSE
The main purpose of the project was to construct 6 storey’s
Commercial building
COMPANY
SOURCE OF FUNDS AND MANAGEMENT.
Western Engineers Limited’s main source of funds is
the on-going projects performed by the company regional wise. The company
performs many big projects in Arusha at a rate of 3 projects per year.
Other sources of funds to the company are bank loans
and small businesses. Loan from banks has not been an effective source since
the interest rates were raised and hence minimized the profits from the
project. This is the main setback to the progressively growing construction
companies.
WEEKLY REPORTS
1ST WEEK SUMMARY
BEAM
CONSTRUCTION
The beams are the horizontal load bearing structures;
they are used to transmit load to the column the slab would be supported by
those beams.

SKILLS AND MANPOWER
·
Structural
engineer
·
Site
engineer
·
Technicians
·
4 unskilled labours
MATERIALS
·
Ply wood shutters
·
Nails
·
Grade 25 concrete
·
High tensile steel of diameter 25mm,
20mm, 12mm,10mm and 8mm,(Y25, Y20, Y12,Y10 andY8) complying BS 4661 grade 460.
·
Binding wires
·
.Spacer block
TOOLS/MACHINE/EQUIPMENTS USED
·
Plywood cutting machine
·
Hammer
·
Tape measure
·
Grander machine for cutting steel bars
·
Pair of pincers ( for tightening and
cutting wires)
·
Claw bar (for bending the steel bars)
were made by Y32
PROCEDURES
·
The steel bars were cut in their lengths
and bent to as illustrated in the bending shadle and transported just near by
the slab
·
The steel bars were lifted using ropes
from the ground to the 1st floor level
·
Spacer blocks were positioned in the
bottom of beams to ensure that bottom bars acquire enough concrete cover and
prevent their oxidation and rust
·
The steel bars were fixed starting from
the beam bottom top bars and attached by rings via wire binders followed by
slab bottoms and tops separated by chairs
·
Spacer blocks were inserted throughout
the whole portion with steel bars ready for concreting
INFLUENCE OF THE
ENVIRONMENTAL CONDITION
Weather: had no
any adverse effects in steel fixing activities
LIMITATION
·
receiving of some low quality
reinforcement i.e. brittle steel from the suppliers
·
problem of corrosion influenced by the
climate of the site
SAFETY PRECAUTIONS:
·
Helmets
·
Boots
·
Overalls for the concrete team
CONCLUSION:
Beam construction procedures
and techniques are well understood.
2ND
WEEK SUMMARY
STEEL
WORKS FOR SLAB CONSTRUCTION
Slab is the horizontal structure in the building
where the load is exerted and then transferred to the beams where its again
transferred to the columns then down to the foundation and being distributed to
the soil (hard stratum).the slabs is used in making the balcony and floors in
the building as well as is used in carrying the loads.

SKILLS
AND MANPOWER
Ø Students.
Ø Unskilled
labours.
Ø Site
foreman.
Ø Consulting
engineer.
Ø Site engineer.
MATERIALS
·
Ply wood shutters
·
Nails
·
Grade 25 concrete
·
High tensile steel of diameter 25mm,
20mm, 12mm,10mm and 8mm,(Y25, Y20, Y12,Y10 andY8) complying BS 4661 grade 460.
·
Binding
wires
·
.Spacer block
TOOLS/MACHINE/EQUIPMENTS USED
·
Plywood cutting machine
·
Hammer
·
Tape measure
·
Grander machine for cutting steel bars
·
Pair of pincers ( for tightening and
cutting wires)
·
Claw bar (for bending the steel bars)
were made by Y32
PROCEDURES
ü The
working drawings were used to establish the level of underside of the floor
slab. this became the level of the top of the formwork deck.
ü Put
up the supporting framework of props, ledgers, and joists and nails the
formwork deck to the joists. When the formwork had been fabricated and
assembled the interior of the forms should be cleared of all rubbish, dirty and
grease before the application of any mould oil or releasing agent. All the
joints and holes should be checked to ensure that they are grout tight.
ü The
entire structures were leveled by adjusting the wedges and the diagonal bras
were nailed across the props to stiffen them.
ü Inspection
was done to the deck for open joints and the gaps were filled with building
papers and usable materials.
ü The
deck was treated with the oil, which would make it easier to remove the
formwork when finished.
ü The
electrical conduits for first floor wiring and ceiling lights for the floor
below were attached to the formwork.
ü All
others pipes for other services were attached.
ü The
reinforcement bars as shown on the drawings were cut and bent. They were laid
out on the formwork and separated at the intervals by concrete spacer blocks
and spacer bars then the bars were tied in position with the soft steel wire.
INFLUENCE OF THE
ENVIRONMENTAL CONDITION
Weather: had no any
adverse effects in steel fixing activities
LIMITATION
Receiving
of some low quality reinforcement i.e. brittle steel from the suppliers problem
of corrosion influenced by the climate of
SAFETY:
To ensure safety at the
site, the trainees we were given:
·
Helmets to protect their heads against
falling debris and other
·
The use of boots
·
The use of safety belt
·
Overalls for some worker
RECOMMENDATION.
For the safety of labours and quality of
the work all probs must be painted to make them free from rust which may bring
the disaster during the the construction.
3RD
WEEK SUMMARY
CONCRETE CASTING FOR BOTH SLAB AND BEAM
Concrete is used to make foundations, floors, stairs and
roofs. The general principals of making a concrete are that you mix cement,
fine aggregates (sand) and course aggregates with water
Cement:
powder produced from clay and chalk or limestone. In general most concrete is
made up with ordinary or rapid hardening cement and it is act as a binder.
Aggregate:
shape, surface texture and grading (distribution of particle size) which are
factors which influence the workability and strength of a concrete mix.25 mm
course aggregate was used.
Water must be clean
and free from impurities which are likely to affect the quality or strength of
the resultant concrete

SKILLS
AND MANPOWER
Skilled labourers involved: 1 civil engineer,
1Civil technician.
Unskilled labourers involved: 10 labourers.
TIME REQUIRED
The work took total of 48 hours with approximately 8 hours per
day.
MATERIALS USED
·
Sand
·
Manila strings
·
Cement
·
Aggregates
·
Water
TOOLS AND EQUIPMENT
ü Concrete
mixer:.
ü Pumping
machine
ü Poker vibrator
ü Hose
pipe
ü Basket.
ü Spades
ü Steel trowel.
ü Concrete
lift.
PROCEDURES
v Mixing
or Preparation of concrete whereby cement, sand and coarse aggregate in ratio
(1:2:4) were poured into the concrete mixer.
v Ready
mixed concrete were moved to the slab using wheelbarrow and buckets
v Concrete
were then poured to the slab.
v Then
the poured concrete was compacted using vibrator
to remove air inside
v Finally
the concrete were left cured for seven days
SAFETY
PRECAUTIONS;
To ensure safety at the
site everybody were given:
·
Helmets to protect their heads against
falling debris
·
The use of boots
·
Overalls or overcoats
RECOMANDATION.
ü The
cement had been checked whether it was manufactured recently.
ü The
ratio should be controlled while mixing
ü The
workers should have safety gears for their health and safety.
ü The
pegs and marks exposed should be followed while leveling the concrete.
ü The
selection of the equipment should match the work to be done
ü Concrete
should be well compacted.
CONCLUSION:
The week ended safely. Also, the
activities I learned were well and successfully understood and I appreciate
such kind of work.
4TH
WEEK SUMMARY
STEEL
FIXING FOR PROJECTING COLUMN AND SHUTTERING OF THE 1ST STOREY
Formworks for in situ concrete work may be described
as a mould or box into which wet concrete can be poured and compacted so that
it will flow and finally set to the inner profile of the box or mould.
Formwork is the temporary support structure to hold
the wet/green concrete till it hardens
In order to construct formwork, there are
requirements followed to be successful in its function:
Safety:
it
should be strong enough to support the load of wet concrete which is generally
considered to be approximately 2400 kg/m3.
It must not be able to deflect
under load which would include the loading of wet concrete, self weight and any
superimposed loads such as operatives and any barrow runs over the formwork.
Quality:
it
must be accurately set out, concrete being a fluid when placed; it will take up
the shape of the formwork which must therefore be of the correct shape, size
and in the right position.
Economy:
it
should be designed and constructed
so that it can be easily erected and struck, so saving both time and money.
It must have grout-tight joints.
Grout leakage can cause honey combing of the surface or produce fins which have
to be removed. The making good of defective concrete surfaces is both time
consuming and costly. Grout leakage can be prevented by using sheet materials and
sealing the joints with flexible foamed polyurethane strip or by using a
special self adhesive tape.
Form sizes should be designed so
that they are the maximum size which can easily be handled by hand or by
mechanical lifting device.
Material must be chosen so that it
can be easily fixed using either double headed nails, round wire nails or wood
screws. The common method is to use nails and these should be at least two and
half times the thickness of the timber being nailed, in length.
The design of the formwork units
should be such that they can easily be assembled and dismantled without any
members being trapped.
01. TYPES OF THE FORMWORKS
FOR DIFFERENT PURPOSES.
·
Foundation formwork
·
Column formwork
·
Beam formwork
·
Slab formwork
·
Stair-case formwork

SKILLS
AND MANPOWER
·
Site engineer
·
Students
·
Site foreman
·
Unskilled labourers
MATERIAL
USED
ü Marine
board for making column.
ü Timber
(1”*6”, 1”*8”, 1”*10” and 2”*4”).
ü Nail
(3”, 4” and 2.5”).
ü Props.
TOOLS/
MACHINES
·
Plywood cutting machine
·
Hammer
·
Tape measure
·
Grander machine for cutting steel bars
·
Pair of pincers ( for tightening and
cutting wires)
·
Claw bar (for bending the steel bars)
were made by Y32
·
Binding
wires
PROCEDURES
·
The steel bars were cut in their lengths
and bent to as illustrated in the bending shadle
·
The steel bars were lifted using ropes
from the ground to the 1st floor level

INFLUENCE OF THE
ENVIRONMENTAL CONDITION
Weather: had no any
adverse effects in steel fixing activities
LIMITATION
Receiving
of some low quality reinforcement i.e. brittle steel from the suppliers problem
of corrosion influenced by the climate of
SAFETY:
To ensure safety at the
site, the trainees we were given:
·
Helmets to protect their heads against
falling debris and other
·
The use of boots
·
The use of safety belt
·
Overalls for some worker
5TH
WEEK SUMMARY
CONCRETE CASTING FOR COLUMN
Concrete is used to make foundations, floors, stairs,columns
and roofs. The general principals of making a concrete are that you mix cement,
fine aggregates (sand) and course aggregates with water
Cement:
powder produced from clay and chalk or limestone. In general most concrete is
made up with ordinary or rapid hardening cement and it is act as a binder.
Aggregate:
shape, surface texture and grading (distribution of particle size) which are factors
which influence the workability and strength of a concrete mix.25 mm course
aggregate was used.
Water must be clean
and free from impurities which are likely to affect the quality or strength of
the resultant concrete
The following figure
shows the column that is casted with concrete

SKILLS AND MANPOWER
Skilled labourers involved: 1 civil engineer,
1Civil technician.
Unskilled labourers involved: 10 labourers.
TIME REQUIRED
The work took total of 48 hours with approximately 8 hours per
day.
MATERIALS USED
·
Sand
·
Manila strings
·
Cement
·
Aggregates
·
Water
TOOLS
AND EQUIPMENT
ü Concrete
mixer:.
ü Pumping
machine
ü Poker vibrator
ü Hose
pipe
ü Basket.
ü Spades
ü Steel trowel.
ü Concrete
lift.
PROCEDURES
v Mixing
or Preparation of concrete whereby cement, sand and coarse aggregate in ratio
(1:2:4) were poured into the concrete mixer.
v Ready
mixed concrete were moved to the slab using wheelbarrow and buckets
v Concrete
were then poured to the columns.
v Then
the poured concrete was compacted using vibrator
to remove air inside
v Finally
the concrete were left cured for seven days
SAFETY
PRECAUTIONS;
To ensure safety at the
site everybody were given:
·
Helmets to protect their heads against
falling debris
·
The use of boots
·
Overalls or overcoats
RECOMANDATION.
ü The
cement had been checked whether it was manufactured recently.
ü The
ratio should be controlled while mixing
ü The
workers should have safety gears for their health and safety.
ü The
pegs and marks exposed should be followed while leveling the concrete.
ü The
selection of the equipment should match the work to be done
ü Concrete
should be well compacted.
CONSTRUCTION OF
STAIRS CASE OF FIRST FLOOR
INTRODUCTION
A
stair is a number of at least 3 steps leading from one level to another in
order to provide means of movement between different levels of floors of a
building
The
stairs were located such that they save the purpose for they are provided, all
planning needs and consideration of all possible factors were cared, and the
stairs were placed near the main entrance since the building is for public uses
ü The type of
stairs we constructed was concrete stairs which are widely used in all types of
buildings
The
waist thickness was 195mm
Number
of steps constructed= 7 steps
Height
of flight of rise= 200mm
Going
of flight =3600mm
Skills and Manpower
Skilled labourers: 3civil technician, 3engineer,8
unskilled: 25labourers
Time required
The work took 8 hours
Material used, their sources and origin
·
Course
aggregates
·
fine aggregates
·
Portland
cement
·
timber and marine boards for formworks
·
nails
·
Reinforcement
bars (steel bars of diameter of 12mm).
·
Spacers
·
Binding
wire
·
Marker(chalk)
Tools and
machinery used
Concrete mixer, hammer, hand saw,
buckets, tape measure, spirit level etc
PROCEDURES
FOR THE CONSTRUCTION OF STAIRS
·
preparation
of material for formwork and timber supports
·
measurements
to know dimensions and space to locate formwork, to set out -the height from
one floor to another was first checked, that total rise was divided into a
suitable numbers of risers and then the proportionate size to the go was
calculated
·
formwork
was fixed according to the required dimensions
·
Steel fixing on the formworks of stairs
Ø main
steel bars were placed on the formwork at an appropriate distance apart
according to the specific engineering drawings
Ø marking
off the dimensions using a chalk for placing distribution bars i.e. 200mm
Ø The
main bars were crossed at 90 degrees with steel bars at an approximately 200
apart and firmly tied using binding wire with the help of a pincer.
Ø The
fixed reinforcements were overlapped with the previously steel used to
reinforce the foundation projecting upwards of floor concrete with dimensions
of approximately 400mm found at the start and at the end of the stair case.
Bending of protruding steel was
simply done using special mould.
Ø Additional
crossing bars were fixed with ready placed steel together with foundation
reinforcements projecting.
Ø Block
spacers of 1 inch were properly placed beneath the steel reinforcements for the
aim of providing an adequate concrete cover to avoid the corrosion of steel.
·
Formworking for the steps was accurately
done, verticality and horizontality of formwork was ensured using the spirit
level, the riser was 150mm and the going was 300mm.
FORMWORKING AND STEEL FIXING FOR STAIRS

·
Watering of formwork was done prior to
the casting of concrete
·
Concreting was done on the constructed structure of
formwork by starting on the lowest to the highest point
CONCRETING

·
Compaction was properly done using the
poker vibrator
·
Curing of stairs continued and stripping of formwork was later done
Influence
of environmental conditions
Weather:
dry/sunny
Work
of concreting for stairs was affected by dry condition where by much water
evaporates and leading to poor hydration process of the concrete consequently
result to frequent curing to control excessive loss of water by evaporation
Limitations
Difficulty in attaining levels
of the forms with the use spirit level and uniform dimensions of goings.
Safety precautions
Safety
tools: gumboots, safety goggles, hard helmet, etc.
Safety
precautions taken:
(i) Wearing
safety gears like hard helmet to ensure maximum protection of workers from site
risks.
(ii) Wearing
of open shoes like slippers is strictly prohibited for the workers; they should
put in closed shoes to protect them from injury.
(iii) Long
sleeves and pants to reduce skin exposure to concrete or cement dust.
(iv) Remember
to wash your hands and before eating, drinking .
Conclusion and
recommendation
Advantages of concrete stairs include;
·
Higher
fire resistance
·
Can
be casted in any desired geometrical pattern and desired color finish
·
Lower maintenance cost compared to other types of
stairs
As recommended they must be
proportionally right, aesthetically pleasing, and uniform and dimensionally
correct.
6TH
WEEK SUMMARY
SHUTTERING
OF BEAMS OF 2ND STOREY
Formwork is the term given to either temporary or
permanent mould into which the concrete or similar materials are poured
A beam formwork consists of a three sided box which
is supported by cross members called head trees or props which were propped to
the underside of the soffit board. The floor or roof slab formwork is sometimes
called shuttering and consists of panels of size that can be easily handled.
The beam form was also used to support the slab formwork and the two structural
members were cast together
The slab
beams formwork consist of support (props) arranged in rows spaced in 150mm to
200mm apart depending on the thickness of slabs. At our site the beam formwork
were immediately supported by the columns.
In order to construct formwork, there are
requirements followed to be successful in its function:
Safety:
it
should be strong enough to support the load of wet concrete which is generally
considered to be approximately 2400 kg/m3.
It must not be able to deflect under
load which would include the loading of wet concrete, self weight and any
superimposed loads such as operatives and any barrow runs over the formwork.
Quality:
it
must be accurately set out, concrete being a fluid when placed; it will take up
the shape of the formwork which must therefore be of the correct shape, size
and in the right position.
Economy:
it
should be designed and constructed
so that it can be easily erected and struck, so saving both time and money.
It must have
grout-tight joints. Grout leakage can cause honey combing of the surface or
produce fins which have to be removed. The making good of defective concrete
surfaces is both time consuming and costly. Grout leakage can be prevented by
using sheet materials and sealing the joints with flexible foamed polyurethane
strip or by using a special self adhesive tape.
Form sizes should be
designed so that they are the maximum size which can easily be handled by hand
or by mechanical lifting device.
Material must be chosen
so that it can be easily fixed using either double headed nails, round wire
nails or wood screws. The common method is to use nails and these should be at
least two and half times the thickness of the timber being nailed, in length.
The design of the
formwork units should be such that they can easily be assembled and dismantled
without any members being trapped.
TYPES
OF THE FORMWORKS FOR DIFFERENT PURPOSES.
·
Foundation formwork
·
Column formwork
·
Beam formwork
·
Slab formwork
·
Stair-case formwork
SKILLS AND MANPOWER
·
Site foreman
·
Students
·
Unskilled
labourers
MATERIAL USED
ü Marine
board as the side of beam slabs form work.
ü Timber
(1”*6”, 1”*8”, 1”*10” and 2”*4”).
ü Nail
(3”, 4” and 2.5”).
ü Props.
1.2
TOOLS USED
ü Hand
saw.
ü Tape
measure.
ü Rope
for lining.
ü Spirit
level for lining.
ü Claw
hammer and ladders
PROCEDURES
v The
all materials were prepared, as the timbers were planed to the required size
(1”*6”, 1”*8”, 1”*10” and 2”*4”) and the props were cuts to the required size.
v The
soffits of the beams were constructed first followed by the side of the beams internally
and the slabs soffits were constructed per the drawing.
v The
props were placed 150mm to 200mm apart so as to sustain the loads of and beams.
v Lastly
the external side were placed per the drawing and supported per specification
as shown to the drawings.
INFLUENCE OF THE
ENVIRONMENTAL CONDITION
Weather: had no any
adverse effects in steel fixing activities
LIMITATION
Receiving
of some low quality reinforcement i.e. brittle steel from the suppliers problem
of corrosion influenced by the climate of
SAFETY:
To ensure safety at the
site, the trainees we were given:
·
Helmets to protect their heads against
falling debris and other
·
The use of boots
·
The use of safety belt
·
Overalls for some worker
7TH
WEEK SUMMARY
SHUTTERING
OF SLAB OF 2ND STOREY
Formwork is the term given to either temporary or
permanent mould into which the concrete or similar materials are poured

SKILLS AND MANPOWER
·
Site foreman
·
Students
·
Unskilled
labourers
MATERIAL USED
ü Marine
board as the side of beam slabs form work.
ü Timber
(1”*6”, 1”*8”, 1”*10” and 2”*4”).
ü Nail
(3”, 4” and 2.5”).
ü Props.
TOOLS USED
ü Hand
saw.
ü Tape
measure.
ü Rope
for lining.
ü Spirit
level for lining.
ü Claw
hammer and ladders
PROCEDURES
v The
all materials were prepared, as the timbers were planed to the required size
(1and the props were cuts to the required size.
v the
slabs soffits were constructed per the drawing.
v The
props were placed 150mm to 200mm apart so as to sustain the loads of and beams.
v Lastly
the external side were placed per the drawing and supported per specification
as shown to the drawings.
INFLUENCE OF THE
ENVIRONMENTAL CONDITION
Weather: had no any
adverse effects in steel fixing activities
LIMITATION
Receiving
of some low quality reinforcement i.e. brittle steel from the suppliers problem
of corrosion influenced by the climate of
SAFETY:
To ensure safety at the
site, the trainees we were given:
·
Helmets to protect their heads against
falling debris and other
·
The use of boots
·
The use of safety belt
·
Overalls for some worker
8TH
WEEK SUMMARY
BLOCKWORKING
A wall is a vertical solid structure, made of stone,
bricks, blocks or reinforced concrete, which surrounds, divides or protects an
area of land. For our site, we had the walls of blocks except on the lift where
we used reinforced concrete and we had stretcher bond.
The strength and durability of wall is primary
depend on the following factors:
i.
The quality and strength of the blocks
ii.
The type of the mortar used
iii.
The method of bonding used in the
construction
Mortar is usually a mixture of cement and sand or
lime and sand or mixture of the three i.e. cement, sand and lime. For our site,
we had mortar of cement and sand with the ratio of 1:5 (cement: sand)
On site, we have two types of walls:
1.
Load-bearing
walls (230mm): Transfer load to the foundation/support
and are usually external walls and those supporting roofs, upper floors and
other components in a building.
2.
Non-load
bearing walls (Partition walls: 150mm): Dividing rooms
SKILLED AND MAN POWER USED
·
Foreman
·
3 craftsmen
·
3
Uskilled labours
·
2 trainees students
MATERIALS
·
Sand
·
Cement
·
Blocks
·
Water
TOOLS/MACHINE/EQUIPMENTS
USED
·
Trowel
·
Spade
·
Hammer
·
Spirit level
·
Plumb bob
PROCEDURE
·
Mortar mixing
·
Placing the guiding blocks at the ends
of the wall location
·
Placing the rope to guide block aligning
·
Water pouring to the zone to be built in
order to remove the dust
o
Spreading the mortar using the trowel
and maintain the level using the spirit level
·
Arranging of the blocks and binding them
with the sand-cement mortar using English type of bonding
PROBLEMS
During this week the main problem
encountered was the shortage of cement
SAFETY:
To ensure safety at the
site, the workers were given:
·
Helmets to protect their heads against
falling debris and other objects.
·
Few workers had their own boots to cover
their legs when working and thus protecting them against injuries
CONCLUSION:
The week ended safely since
there wasn’t any problem happened or reported. Also, the activities I learned
during the six week were well and successfully understood.
SPECIFIC
REPORT
STEEL
FIXING FOR SLAB (REINFORCEMENT OF SLAB)
Slab is the major part on the building in which the
partition of rooms are made after casting with concrete. The reinforcement on
slab that comprise of:-
·
bottom (bottom one and bottom two) and
·
top bars (top one and top two).
These bottom and top bars are separated by the use
of spacer chairs which is placed between them, normally the bars are placed on
the top of slab formwork which is constructed by the use of marine board or
plywood

Reinforcing steel in slab acts not only to resist
tensile forces, but also compression. Reinforced concrete gets its strength
from the two materials, steel and concrete, working together. To get them
working together, it is critical that the steel be adequately bonded to the
concrete.
Since in any building that involve the
use of concrete that is mixture of cement, sand, aggregates and water there
must be involvement of steel due to the fact that concrete is rich in compression
and the compensation of this is steel which is rich in tension,
Reinforcement includes deformed bars, plain
bars, wire, fabric and steel products, all of which increase the tensile and
compressive stress carrying properties of concrete. Steel reinforcement is also
the essential contributor towards crack control of concrete structures.
ADVANTAGE
OF STEELS WHEN USED AS REINFORCEMENT
Steel is used as reinforcement in concrete owing to
its following qualities
·
High tensile strength
·
Good bond with concrete
·
Nearly same coefficient of expansion as
that of concrete
·
Adequate quality control possible during
the manufacture of steel
BASIC
REQUIREMENTS TO BE SATISFIED BY REINFORCING BARS
Ø Bond
strength
Ø Ductility
Ø Bend
ability
Ø Weldability
Ø Fatigue
strength
Ø Corrosion
resistance
Ø Fire
resistance
PRECAUTION
FOR STEEL BARS IN REINFORCEMENT
·
Should be stored in such a way to avoid
distortion and corrosion
·
Should not be clean by oily substance to
remove rust
·
Bars are bent correctly and accurately
to the size and shape shown to their required drawings
·
If possible bar of full length is used
·
No overlap is given in the bar having a
diameter more than 36mm
MATERIALS
USED
v High
tensile steel:, Y16, Y12, Y8.
v Binding
wire
v Spacer
block
v Pincers
TOOLS/EQUIPMENTS/MACHINE
USED
·
Pair of pincer
·
Crow bar(Y20, Y16)
·
Bender (Y20)
·
Tape measure
·
Bending pipe
·
Grander machine
THE
LOCAL BENDING MACHINE:
The machine was made out of woods, nails and an iron wage. For ring
making machine, the nails were set to give the dimensions of the rings. The
distance of the nails from the wages depended on the required length to bend
(whether width or height of the ring). When bending, the bar to bend was
inserted into a pipe to increase the bending moment and thus simplifying the
task.
The diagram below shows how other machine can be
prepared and placed for steel bending process.

CUTTING
AND BENDING PROCESS
Using a cutting machine (grander), the bars were cut
into different sizes including anchorage bends
Using bending machines, the bars were bent into the
required shapes depending on their use. The bending machines the local
(manually operated) machine.


CUTTING
PROCESS BENDING
PROCESS
ARRANGEMENT
OF STEEL BARS IN THE SLAB
PROCEDURE/PROCESSES
USED
·
Obtaining the dimension on building that
is space enclosed by slab and the whole parts of building
·
Cutting the steel bar on required
dimension by using grander and bending them on appropriate shape
·
Fixing them on the required position
into the slab as stated or shown on drawing with binding wire.
·
Steel bars are arranged in the slab into
tops and bottoms whereby there are top one and two and bottom one and two in
which they are given spaces by considering the diameters used
·
Normally bottoms one and two are full
placed to the slab
·
the top one and two are not necessarily fully
placed(the top one and two are placed 1/3 of each end of the slab leaving the
middle part empty of steel bars)
CONSTRUCTION
OF SLABS
DIAMETERS
OF THE BARS USED IN THE SLAB AND THEIR SPACING
When reinforcing slab we arrange bottom (bottom one
and bottom two) and top bars (top one and top two) in different spaces by
considering their diameter
DIAMETER
|
SPACING
|
8mm
|
50mm
|
10mm
|
100mm
|
12mm
|
150mm
|
16mm
|
200mm
|
TOLERANCES
IN PLACING BARS
The strength of any concrete structure can be
affected by improper positioning of the reinforcing bars. For example, the
lowering of the top bars or raising of the bottom bars by 10mm more than
specified in a 15cm slab could reduce its load-carrying capacity by 20%
PROBLEMS AND
RECOMMENDATIONS
Problems encountered during construction include;
·
Low technology; the technology used in most site
activities was very poor. For example lifting up steel bars from the ground to
the second floor was done by using a rope. This made the work very difficult
and time consuming. Above all it was very dangerous for the ones performing it
because the steel bars might have pulled them down the ground if they weren’t
strong enough.
·
Lack of sufficient safety gears; safety gears
especially those to be used during concrete casting were very few. These
included gloves and gumboots. Also in days where many workers were needed the
helmets become insufficient.
·
Lack of first
aid kit; there was no safety aid in the site for emergency purposes just in
case an accident occurred in the course of working.
·
Changes in the working drawings which occurred in
course of construction is another challenge for the project.
- Relating office design
works to real site conditions.
- Untimely ordering of new
safety gears to replace the worn out ones.
- Insufficient provision
of safety education among laborers.
- Untimely payment of
laborers.
RECOMMENDATIONS ON SOLVING THE PROBLEMS:
- The client should make all the
necessary changes at the early stages of the project to avoid
inconveniences which may occur when changes are done in the course of construction.
- Drawings should be
available at the working places to provide a direct link between the
drawings and the actual work.
- There should be sufficient
provision of education on the importance of safety to the laborers.
- Sufficient provision of
safety gears like boots, helmets, gloves and masks to fulfill the demand.
- Workers should be properly paid to
avoid inconveniences
- The community should be educated
about the HIV/AIDS awareness.
- There should be regular replacement
of the worn out safety gears.
There should be a site first aid kit for
emergencies
0 Comments