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

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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.

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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.