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INDUSTRIAL FIELD VISIT ON THE ELS PRE-CAST YARD
AT SOORIYAWEWA
(10th Feb 2012)
Name : Bandara K.A. J.M.
Reg No : RU/E/2008/014
Date : 29/03/2012
1
ACKNOWLEDGEMENT
I take this opportunity to thank everybody those who helped me in various ways. First and foremost I
would like to thank the Engineering laboratory services (ELS), to organizing and arranging such an event
in order to get knowledge.
Especially I express my sincere gratitude to faculty of Engineering University of Ruhuna for giving me
such an opportunity. Also it’s my duty to thank Dr. G.S.Y. De Silva for organizing such an event to
improve the knowledge and giving us a great opportunity to visit the location.
Last but not least I would like dedicate my special thanks to my colleagues and family members for the
tremendous support and encouragement given and to all those who made this possible.
2
CONTENT
Page
ACKNOWLEDGEMENT 01
1.0 INTRODUCTIONS 03
2.0 PRECAST REINFORCED CONCRETE PILE 04
2.1 CONSTRUCTION STEP 04
3.0 ELECTRIC POLES 06
3.1 ADVANTAGES OF PRESTRESSING 07
3.2 TEST OF STRAIGHTNESS OF POLE 08
4.0 HUME PIPE CONSTRUCTION 08
5.0 INTERLOCKING BLOCKS 09
6.0 MASONRY BLOCKS 09
7.0 PRE-STRESSED CONCRETE SLEEPERS 10
8.0 OTHER PRODUCTS 11
DISCUSSION 12
3
1.0 INTRODUCTIONS
The industrial field visit to Sooriyawewa was organized by the Department of Civil and Environmental
Engineering under faculty Of Engineering, Hapugala, in order to accustom knowledge about the pre –
stress concrete structures and other construction process. The time duration being one day from 10th Feb
2012 was spend to study at Sooriyawewa pre-cast yard of ELS construction (pvt) Ltd.
The ELS Construction (pvt) Ltd is proudly announce to all esteemed Professionals, Consultants
and Contractors involved in the Construction Industry of the establishment of a well-equipped material
testing and quality control laboratory to meet all such requirements of the construction industry in the
new millennium.
This yard produced several engineering construction produces. Mainly electrical poles, pavement block,
precast pile and also bridge beam and road components.
Poles (CEB)
Reinforcement Concrete Piles
Hume Pipes
Sleepers
Slab system
Fence Post
Building Products
Boundary Wall Products
Hollow Blocks
RC Bridge Components
Drain Elements (U Flumes)
Road Work Elements
4
METHODOLOGIES AND TECHNOLOGY
2.0 PRECAST REINFORCED CONCRETE PILE
The most common pile type in many parts of the world is the precast concrete pile. Precast concrete piles
are commonly manufactured in this yard is square and ranging from about 250 mm to about 450 mm,
with a maximum section length of up to about 10 m.
The piles have generally been driven with a drop hammer of 3 to 4 tons. Maximum allowable axial loads
can be up to about 1 000 kN. The length of pile sections is often dictated by practical considerations
including transportation, handling problems in sites on restricted area and facilities at the casting yard sot
that were produced 7m length pile. Precast concrete piles are not suitable for soil deposits containing a
significant amount of boulders. In such cases, the pile may be equipped with a pile shoe, which protects
the pile tip during hard driving.
2.1 CONSTRUCTION STEP
The moulds, joined together in rows, are individually formed and separated between each row. After
casting and initial curing the rams operated the cams enabling the moulds to flex for easy stripping or
striking of the pile.
Figure 2.1 7m precast pile
5
All piles are reinforced full length with cages made from high tensile steel coil fed through a purpose
built computer controlled fabricating and welding robot. The fully automatic robot wraps hard drawn
stirrup wire around the main bars and welds every metal-to-metal joint to produce an exceptionally
rigid cage.
The cages are placed in the special moulds ready for casting the perfectly symmetrically square
section piles. Pile sections incorporate full-length chamfered corners and a domed head, which
dispenses with reinforcement bands needed for driving conventional flat-topped piles.
Main-Bar and shear-steel reinforcement have been caged which are both fabricated and positioned
very accurately over the full length of the pile section.
Use of a concrete with an appropriate mix design(50Grade) provided by an approved ready-mix plant
that is fully integrated into the production process.
Figure 2.2 Reinforcement precast pile Figure 2.3 Hydraulic vibrate
Figure 2.4 Steams chamber Figure 2.4 Coconut steams boiler
6
The boiler that is provided steam for steam curing is run by using diesel or coconut shells. Using of
coconut shells is cheaper than using of diesel. Piles are entered into a room and door of the room is
closed. Then steam is provided into the room by using pipes which comes from the boiler. Piles are
vibrated before entering the room to prevent honey cones and gain maximum strength itself. A surface
vibrator is used for the vibration. Five or six piles are vibrated as once and entered into the curing room.
3.0 ELECTRIC POLES There are 2 types of electric poles such as solids and hollow. All poles are constructed according to the
CEB specifications and requirement. They are manufactured in a wide range of strengths and sizes to fill
most requirements in MV and LV lines. Steel reinforcement used for the CEB poles and High tensile steel
wire used for pre-stressing normally 12.5mm diameter wire used for pre-stressing. Ordinary Portland
cement used as cement and 50 N/mm2 strength ready-mix concrete used.
Figure 2.5 Raw material of coconut Figure 2.6 Diesel steams boiler
Figure 3.1 Reinforcement of pole Figure 3.2 Mould of pole
7
High tension reinforcement wire that is imported by India are used to pre stressed electric poles. Lock cut
are join to 2 sides of the reinforcement. One side is jack and the other side is fixed. A force of 140 bars is
provided to high tension reinforcement. 10 electric poles can be casted in one bed. After 7 days of
concreting the reinforcements are released and the excessive parts of there reinforcement wires are cut.
Then anti corroded paint is applied at both end of the poles.
3.1 ADVANTAGES OF PRESTRESSING
The use of pre-stressed concrete offers distinct advantages over ordinary reinforced concrete. These advantages can be briefly listed as follows:
• Pre-stressing minimizes cracking by holding the concrete in a state of compression.
• Pre-stressing allows reduced beam depths to be achieved for equivalent design strengths.
• Pre-stressed concrete is resilient and will recover from the effects of a greater degree of overload than any other structural material.
• If the pre-stressed unit is subjected to overloading, cracks which might develop will close as soon as the overloading ceases.
• Pre-stressing enables both structural elements and entire structures to be formed from several precast units, e.g. segmented and modular construction.
• Pre-stressing permits the use of longer spanning members with high strength-to-weight characteristics.
• The ability to control deflections in pre-stressed beams and slabs permits the use of longer spans.
• Pre-stressing permits a more efficient usage of high-tensile steel and high strength concrete.
Figure 3.3 Reinforcement wires end Figure 3.4 Curing processes of poles
8
3.2 TEST OF STRAIGHTNESS OF POLE
For measuring uprightness or straightness of a pole, it shall be placed lengthwise (with smaller cross-
section side parallel to rigid surface) on a rigid straight surface. Then using a measuring steel scale at
graduated in mm, measure the distance (deviation) of pole surface from the rigid surface at several
locations along the length of the pole. At least two measuring in each one meter length of the pole should
be taken. The largest value of the measured distance shall be taken for determine uprightness. Similar
measurement should be taken on the pole laid with larger cross-section side parallel to the rigid surface.
4.0 HUME PIPE CONSTRUCTION
There are several sizes of Hume pipes in different diameters like 100, 200, 300…1200mm etc. The
construction method of Hume pipes is as bellow. Hume pipe are casted according to the centrifugal
method by using a dry concrete. Thickness of the pipe and the quality is maintained. Pipes are casted
according to SLS certificate. 10mm main bar is used to construction. Auto feeding concrete machine is
used to apply concrete to the casting. Cover blocks are used to maintain the thickness of the pipe.
First the reinforcement net placed inside the shutter and then it was placed on the wheels and the mortar
was started, the shutter was allowed to rotate sometimes. Then while rotating concrete was added from
both sides of the shutter. Then time to time concrete was diffused by using a stick. Also sand and water
should be added to keep the mixer uniformly throughout the shutter. After concreting process finished the
pipes kept about 3 days and then the shutter was removed. Then the pipes were kept in a tank to give a
sufficient curing.
The 3 edge bearing test is done for the cylinder in load for linear meter. There are required load according
to ISO certificate. The check for cracking is done at the bottom and the top. Here the crack widhth and the
depth should be satisfy. The crack width should be 4 -2 mm. then the ultimate load is supplied.
Figure 4.1 Reinforcement of Hume pipe Figure 4.1 Hume pipe mould
9
5.0 INTERLOCKING BLOCKS
There is a high trend to use interlocking blocks for road construction and sustainable building
construction due to their low cost and thermal comfort. ELS (Pvt) Ltd has its own patent for interlocking
block casting machine and quarry dust, river sand and ordinary Portland cement were used to cast to brick
with 7-8 Mpa compressive strength. There are more types of bricks according to their shape and task.
6.0 MASONRY BLOCKS
There are hollow and solid type masonry blocks. The most economical and easiest one is hollow blocks.
A one story building can be made by using hollow blocks within one month. Plaster is no need for hollow
block constructions. 18kg of Cement and 140kg of Corry dusts are used to made masonry blocks. If we
use interlocking hollow blocks the foundation should be flat and the finishing is better than using of other
masonry blocks.
Figure 5.1 A type of blocks Figure 5.2 Mixing machine of mortar
Figure 6.1 compressive machine Figure 6.2 Produced masonry blocks
10
7.0 PRE-STRESSED CONCRETE SLEEPERS
Production method of pre-stressed concrete sleeper’s Concrete sleepers is same as the construction
method of reinforcement piles. Pre-stressed mechanism will be described in construction of electric poles.
The test for the sleepers is done for the fastness of the sleepers. A load applies to pull out the fastness and
find out the pull out capacity. Center positive bending capacity test and negative bending capacity tests
are done for the sleepers.
8.0 OTHER PRODUCTS
There are some other products such as flower vases, Hand rails, bridge components, Slabs, Beams and
etc. Some of them are under the condition of researching. Constructing of some of them is temporary
stopped because of the rare of the requesting of the field. Some of them such as slabs and beams are pre-
stress while the other is pre cast items.
Figure 7.1 Pre-stressed concrete sleepers
Figure 8.1 concrete roof tiles Figure 8.2 concrete slabs Figure 8.1 Bridge components
11
DISCUSSION
Once heard thing may be forgotten but once visited thing never forgotten. This main purpose of field trip
conducted by Department knowledge requires for engineers in industrial field is fulfilled in this visit.
The subject concrete and structural is really one of the most important subjects for civil engineer. Finally
it will be better to say that if there had not been any field visit, we would not have learnt a lot of this
information as theoretical knowledge is not enough for field work. So this information helped a lot us for
study and later on during field works.
So I recommend ELS precast yard at Sooriyawewa is a very good location to visit as an undergraduate
who are mainly involve in that section. Not only it helps to develop the knowledge, gives us a great
practice too. Nowadays people tend to use new findings rather than old conventional things. ELS is a
place, which has higher influence in new innovations. So I think it is a very good place to visit and get
some idea about their findings and creations also well.