report draft
TRANSCRIPT
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ACKNOWLEDGEMENT
It is with great pleasure and learning spirit that we bringing out this industrial training
report. We use this opportunity to express our heartiest gratitude to the support and guidance
offered to us from various sources during the courses and completion of the training.
We would like to extend our sincere gratitude to Mrs. Sreeja Jacob, Head of the
Department of Civil Engineering, for providing us the opportunity to undertake this industrial
training.
We are very much thankful to our guide Mr. Pramod S, Assistant Professor for
sharing his wealthy knowledge.
We would like to express our profound gratitude to Ms. Aysha Sharvana P, our
beloved sister who had inspired and motivated us to undertake this industrial training.
We convey our sincere gratitude to Mr. P Rameshan (The President, ULCCS), Mrs.
Meena (Technical Engineer, Civil, ULCCS), Mr. Shanil V K, Mr. Jithin, Mr. Chanchal,
Mr. Sandeep, Mr. Nirmal Kumar R, Mr. Jithesh, Mr. Miqdad N V, Mr. Akhil, Mr.
Anuraj, Mr. Naveen (all Assistant Engineers, ULCCS), The Project officer at Govt. Cyber
Park, Calicut, Mr. Viswanathan (Retd. Chief Engineer, PWD), Mr. Riyas (R E Wall
Technician, Mukkam Kadavu Bridge) for providing us valuable advice and guidance during
the training and also to all the staffs and labourers of ULCCS for the help and services they
rendered.
Above all, we owe our gratitude to the Almighty for showering abundant blessings
upon us. And last but not the least we wish to thank our parents and our friends for helping us
to complete our industrial training work successfully.
MOHAMMED SAJEEM A
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ABSTRACT
The goal of the industrial training that we have undergone at Uralungal Labour
Contract Co-Operative Scociety (ULCCS Ltd.) was to gain a general idea about various
construction methods, techniques, materials and equipments used in differents construction
works which are on progress, around. The training provided us a first hand opportunity to
expeerience actual site works, its challenges and its thrills. As quality and teamwork are the
primary motives of the company, the training experinces were uniquely great.
Training works were conducted at various sites under ULCCS Ltd. and we could
study very much about different types of civil engineering works. Through this report, we
aim to present a brief outline about every works we were trained in.
We are not arguing that this is a complete description of the works; it’s just an outline
of the same.
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CONTENTS
1. INTRODUCTION
2. SWIMMING POOL WORK AT NADAKKAVU
2.1 LAND PREPARATION
2.2 CONSTRUCTION
2.3 FINISHINGS
2.4 WATER TREATMENT
3. PILE WORK FOR KERALA FEEDS
3.1 PROCEDURE
4. ROAD WORKS FOR GOVT. CYBERPARK, CALICUT
4.1 LAND DEVELOPMENT
4.2 FORMATION OF ROAD
4.3 DRAINAGE DETAILS
4.4 REINFORCED EARTH WALL
4.5 COMPOUND WALL
5. PILING WORK FOR EMS HOSPITAL
5.1 SOIL TEST DETAILS
5.2 LEVELLING
5.3 BORING
5.4 REINFORCEMENT
5.5 CONCRETING
5.7 PILE CAP
6. SWIMMING POOL WORK AT Pe-Co-C, PERINTHALMANNA
6.1 CONSTRUCTION
6.2 FINISHINGS
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7. CONSTRUCTION OF BRIDGE AT MUKKAMKADAVU
7.1 STRUCTURAL DETAILS OF BRIDGE
7.2 CONSTRUCTION OF RE WALL
8. ROAD WORK AT TIRUR
8.1 CONSTRUCTION OF PAVEMENT
8.2 CONSTRUCTION OF CROSS-DRAINAGE WORK
8.3 CONSTRUCTION OF RETAINING WALL
9. CONCLUSION
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LIST OF FIGURES
1. SWIMMING POOL CONSTRUCTIO, NADAKKAVU
2. SITE LAYOUT OF NADAKKAVU POOL
3. LATERAL DIMENSIONS OF POOL
4. STRUCTURAL DETAILS OF POOL
5. PEARL TILE
6. LIGHTING FITTINGS FOR POOL
7. SAND FILTERS OF POOL
8. PILING WORKS FOR KERALA FEEDS
9. SITE LAYOUT
10. LAYOUT OF PILES FOR SILOS TANK
11. BORING BY DMC METHOD
12. REINFORCEMENT UNITS FOR PILES
13. LAND DEVL. AND ROAD WORK AT CYBER PARK
14. EARTHWORK AT CYBERPARK
15. APPLYING GSB LAYER
16. TYPICAL ROAD SECTIONS
17. DRAIN/ COMM/ PLUM DUCTS
18. CATCH PIT VIEW
19. RE WALL
20. THE COMPOUND WALL
21. SECTION OF COMPOUND WALL
22. KEY PLAN OF BORE HOLES
23. BENTONITE MISING PIT
24. REINFORCEMENT DETAILS OF PILE
25. PCC LAYER OVER TWO PILE
26. AFTER CONSTRUCTION OF PILE
27. PILE CAP DETAILS
28. SWIMMING POOL 1 PE-CO-C
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29. SITE LAYPOT
30. SECTIONAL VIEW OF POOL 1
31. ARCHITECTURAL VIEW OF MUKKAM BRIDGE
32. SUPER STRUCTURE OF PIER
33. PILE AND PILE CAP
34. PILE REINFORCEMENT
35. PILE CAP REINFORCEMENT
36. ALIGNMENT OF PIER AND ABUTMENTS
37. PIERS OF CIRCULAR PORTION
38. FACIA PANELS
39. THE GEOGRID
40. STRENGTHENING AND WIDENING OF ROAD
41. WIDENING OF TIPPU ROAD
42. RED SOIL AS SUB GRADE
43. GSB LAYER APPLICATION
44. SECTIONALA VIEW OF BOX CULVERTS
45. PRE-CAST BOX CULVERT
46. PRE-CAST BOX CULVERT UNITS\
47. RR WALL SECTION
48. SIDE POST TIRUR
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LIST OF TABLES
1. BORING LOG OF HOLE 1
2. BORING LOG OF HOLE 2
3. BORING LOG OF HOLE 3
4. SELECTION OF VG PAVING BITUMEN
5. GUIDELINE FOR MODIFIED BITUMEN
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1. INTRODUCTION
Our team of four had seven days to complete the training, which we took as an
opportunity to get trained at seven different sites. We were trained by the ULCCS Ltd. at
their various construction sites where we could study briefly about different civil structures
like Swimming pools, Roads, Piles, Trusses, and Bridges etc.
The first day, we were at the construction of a swimming pool at Nadakkavu
A.U.P.School, Calicut. The project also includes the construction of associated lawn, bath &
dressing room building, Plant room for the water cleaning equipment’s, boundary walls etc.
About 90% of the work has been completed.
We were trained at a 10.106 Acre construction site of Kerala feeds at Thiruvangoor
on the second day, where piling works for Silos tank, truss work for finished goods go down
etc. were on progress. The total site is meant for 17 buildings and 10 silos tanks.
Our third day of training was at Govt. Cyber Park, Calicut. The ongoing 20.46 crore
worth project includes formation of road, Drains, Chamber, Footpath & Parapet wall,
Culverts & Retaining structure, Masonry wall and Chain link fencing. All these works were
at different stages at different chain ages of the road that spanned over a km.
We had a much more thorough training on the fourth day at the 1.266 Acre
construction site for E.M.S. Hospital at Perambra, where different stages of piling and
foundation for a 5 storied building were on progress. Over 82 of 100 piles were completed
and at some portions, rests of the foundation works were also simultaneously on progress.
Our training on the fifth day was at Perinthalmanna, where 2 swimming pools, A
cafeteria and Toilet rooms were under construction for The Pe-Co-C society. One of the
pools was for adults and the other for kids. Around 75% of the works for swimming pools
were completed and a indoor stadium was yet to be built.
Construction of the first Y-Shaped bridge of Kerala across Iruvanhippuzha on
Mukkam-Koodaranhi road was the project we were trained at, on the penultimate day. An
approach road supported by Reinforced earth wall was also a part of the project. The bridge
was to support a 11 m wide road.
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The first phase of Strengthening, Widening and Extension of Tippu Sultan road as a
part of Vallarpadam - Kozhikode west coast corridor at Tirur, for Roads and Bridges
Development Corporation of Kerala Ltd. (RBDCK), was our final work for training. The 4.5
km work worth 17.75 crore includes the drainage works also. Precast box culvert used here is
the first of its kind, to be used in the Malabar region.
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2. SWIMMING POOL WORK AT NADAKKAVU
In the present world the standard for the construction of pools is growing popularity
of swimming and other water activities for sport, fitness, therapy or relaxation has led to the
increased use of swimming pools. Pool constructed should provide facilities that are safe,
hygienic and comfortable for bathers. But in India the construction of swimming pool is
limited to a small scale. The construction of swimming pool at Nadakkavu, Calicut was a
new challenge for District sports council. The land for the construction is provided by A.U.P
School East Nadakkavu and the total cost 1.5 crore was a fund of MLA. The swimming pool
having rectangular shape with 4 tracks and capacity of 4.5 lake liters of water. The total
project includes the construction of swimming pool and adjacent building having facilities for
plant room, office, bathroom, open shower, cafeteria and separate dressing room for both
boys and girls. The estimated duration for total construction was 7 months and is scheduled to
open Oct.15th 2013.
A number of civil structures and their construction details were familiar for us, but the
details in making of a swimming pool were really new and thrilling. We were trained under
the guidance of Mr. Shanil V K, on Sep.27th 2013. About 90% of the work has been
completed by then. The site lay out is shown in Fig.2.2
Fig.2.1 Swimming Pool Construction at Nadakkavu.
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2.1 LAND PREPARATION
The shape of the pool was rectangular having size of 25 m X 12.5 m, and the depth
varied from 1.2 m to 1.7 m from one end to another as shown in fig.2.2 Once the inside
dimensions of the pool are marked out along with the excavation lines, which are 0.5m larger
all the way around, to allow for the thickness of the walls and layers, setting out and digging
started.
Fig.2.3 Lateral dimensions of swimming pool, Nadakkavu
2.1.1 Excavation
A mechanical excavator J.C.B Earth mover was used to excavate the whole
pool. It took almost three days to complete the process. The excavated soil was used
for garden to form a bank, filling in lower area of ground and back filling of
swimming pool side wall. Excess soil was then transported from site by means of
Lorries; obviously the removal of soil from site also extends the time taken to dig the
pool. If the subsoil is gravel, shale or good draining rocky strata, the layer of quarry
muck is not necessary and the concrete floor can be laid direct onto the subsoil. In our
training site the total excavated material was red cohesive soil and no hard strata were
found during the excavation process.
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2.2 CONSTRUCTION
Fig.2.4 Structural details of swimming pool, Nadakkavu
2.2.1 Quarry muck layer
Before the application of quarry muck layer the soil at the bottom of the pool
was well compacted to required depth, so that the soil must possess an optimum
moisture content that produces the maximum density under proctor test. In our project
hand tampers were used for the compaction process. Good compaction of a cohesive
soil reduces permeability and increases shear strength and the stability of the
structure. Above the well compacted soil a layer of quarry muck of depth 40 cm was
provided throughout the bottom of the pool for making the ground stiff and hard for
the further construction.
2.2.2 Reinforcement
The most common cause of cracking in concrete pools is the inadequacy of the
reinforcement used, while it 8 mm steel mesh is sufficient for pools of 1.2 m in depth
with good foundations, it is not adequate for deeper pools. Therefore, 10 mm mild
steel bars were used throughout, these bars can be easily bent to conform with the
shape of the pool and were spaced at 230mm intervals, crossed with bars also at 230
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mm intervals, making 230 mm squares. The crossing top reinforcement was wired
with galvanized wire to the base reinforcement to keep it correctly spaced, this
reinforcement fabrication has to be raised from the floor by 50mm and this was done
with steel chairs. These chairs support the fabrication prior to concreting, and can be
obtained from steel stockholders.
Note: The pipe work from the main drains should be positioned before fixing the
Reinforcement for the pool floor.
2.2.3 Location Of Main Drain and Inlet Pipe work
The main drain was then placed in the middle of the deep end floor ensuring
that the top 40 mm will be above the finished concrete slab in order to allow for the
rendering and the finishing. 4 nos. of 3” dia. drain pipe and 20 nos. of 2” dia. inlet
pipe are used for the fast working of pool. Run the pipe from the main drain through
the concrete floor slab to outside the proposed pool walls, and then brings the pipe up
to the top of the pool. The end of this pipe should then be sealed to prevent any debris
falling into the pipe work during construction.
2.2.4 Concreting
Before starting the reinforcement work for RCC, a layer of 20 cm depth PCC
of 1:4:8 were provided for a getting a hard level surface. The main drain positioned
and all the reinforcing fabricated, the floor is now ready for concreting. It is always
best to carry out all the concreting on the same day, as these results in the strongest
floor, if this is not possible it should be done on successive days. It is always
advisable to use ready mix concrete as the proportions and mixing are always
constant. The concrete used for this particular pool was the grade of M35. The depth
RCC was kept 25.5 cm for both pool walls and base. When moving the concrete into
the pool it was important that it goes well under the reinforcement, at this stage plenty
of labor needs to be available to help with the leveling and vibrating.
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2.2.5 Water Proof Layer
The water proofing of swimming pool was one of the major construction
challenge of pool making at Nadakkavu. And it was the essential layer that was
unavoidable. The inside of the pool shell must have to be rendered with a waterproof
render incorporating “Sealocrete”, “Vandex”. In our site a special multi-coat render
work, “Sika” was used for water proofing. Once applied, the sika admixture reacts
with moisture by expanding into jelly-like substance, blocking all the voids and leaves
the surface with an impregnable seal.
2.2.6 Plastering
Before the beginning of tiling the entire pool should be plastered above the
water proof sika layer. All the bottom corners should be rounded in150 mm curve. A
suitable cement mortar and calculated amount of amount of cement grout were used
for the plastering.
2.2.7 Tile Work
Tile work was the final finish provided at the upper surface of swimming pool.
Variety color of tiles and mosaics were available in market. In our site sky blue
colored “Pearl” brand tiles are used for final finish. The tile used was slip-resistant
and have a surface which is not conducive to slipping under contact of bare feet. It
was designated by the manufacturer as suitable for walking surfaces in wet areas or
for use in pool areas, and coved at the wall juncture for ease of cleaning.
Fig.2.5 Pearl Tile
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2.3 FINISHINGS
2.3.1 Underwater Light
An underwater light certainly transforms a pool during the late evening. One
light is sufficient for pools up to 8.5m x 4.3m but the larger pools do benefit from the
use of two lights. In our site 10 nos. of lightings are provided, when deciding the
position of a pool light, one should always install the light on the side of the pool
nearest the house or the sitting area; in this position the pool will be lit up without
seeing the light itself. Therefore, the best position for the light, if it complies with the
previous rule, is in the center of one of the long walls. When positioning the
underwater light make sure it is installed 875 mm down from the underside of the
pool coping as in the event of bulb failure the light unit can then be lifted out of the
water and changed above water level. The typical light fitting is shown in fig.2.4. The
conduit from the light is then attached to the niche with a waterproof joint which
should then lead out through the back wall up to the deck box fitted at paving level.
The niche should be thoroughly concreted with reinforcement and tied into the pool
walls.
Fig.2.6 Light Fittings for Swimming Pool
2.3.2 Balancing Tank and Channel
The swimming pool constructing in our site is over flowing type. Hence
suitable channels are provided around the swimming pool edge to collect the over
flowing water. This water is then transported to the balancing tank adjacent to the
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swimming pool. The balancing tank should be located below the ground level to
balance the water level inside the pool.
2.3.3 Steps
Total four number of stainless steel ladder are provided for the swimming
pool, one ladder at each corner is located.
2.3.4 Backfilling
There is usually only a small gap of 150mm to backfill and this is done using
gravel, scalping, soil or rejects. The backfilling is done in layers of 300mm and
continues to just below the piping connections, it is then thoroughly consolidated. All
piping should be laid on a bed of sand and then also covered with sand in order to
prevent damage before the backfilling is completed.
2.3.5 Paving
The paving around the pool should be practicable as well as aesthetically
pleasing. Paving should be laid where possible with a fall away from the pool so that
dirt or dust on the paving does not enter the pool after rain; it needs to be non-slip, as
smooth slippery surfaces can be very dangerous. For indoor pools Drain easy is a
simple method of removing splash water enabling the pool surround to be kept dry, if
it is being used, it is installed immediately behind the pool coping before the paving.
2.3.6 Plant Room
The pool equipment needs to be sited in a shed or outhouse, preferably the
building needs to be located as close to the pool as possible and must have an
electrical supply. The plant room and office building for the pool operator was located
about 9 m away from the pool edge at Nadakkavu project. It is detailed in site plane.
It also possesses adequate size to contain the pool pump, sand filter and cleaning
system. etc.
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2.4 WATER TREATMENT
A plant room was constructed attached to the office building. This contains water
treatment equipment’s, sand filters, pH measuring apparatus, drain and inlet pipe control
valves, 2 pumps of 3 HP pumping capacity.
2.4.1 Filtration
Filters are the heart of the pool water treatment and the filter system should
normally be operated continuously. In our site total 8 hr. filtration was required per
day for the complete filtration of pool water and almost 3000 liters of waste water is
estimated to be generated per day. This filtration is carried out by 2 sand filters
(ASTRA POOL, BERLIN), which were located inside the plant room. Filters should
be maintained in a good condition by frequent backwashing and regular inspection.
Conventional sand filters need backwashing at least once a week and much more
frequently in a busy pool. High rate and pre-coat filters require frequent, sometimes
daily backwashing as specified in the manufacturer's guidance.
Fig.2.7 Sand Filters For Swimming Pool, Nadakkavu.
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3. PILE WORK FOR KERALA FEEDS
A 10.106 acre construction site of Kerala Cattle feeds at Thiruvangoor was our
training site on Sept.9th.2013 under the guidance of Mr. Jithin and Mr. Chanchal. The
construction at the site was boring for 300 piles. Almost 80 piles were casted by then and
making of silos tank above the pile and pile cape were started. The total site is meant for 17
buildings and 10 silos tanks. The layout of the site is given Fig.3.2.
Fig.3.1 Piling Work for Kerala Feeds, Thiruvangoor
A total of 120 piles were to be constructed for the foundation of 10 silos tank. Each
tank require a foundation resting on a pile cap connecting 10 piles in a circle and 2 pillars
outside it. The layout of piles is as shown in fig.3.3. The piles are of diameter 700mm for
which M30 Grade reinforced concrete is used. Each piles are required to carry a load of 112
tonnes. The piles are end bearing type, which rest on hard rock strata underground. At this
site, the hard rock was found at 10-13m depth. If no rock was found, friction piles might be
required. A pile cap was built, connecting a set of piles for a tank, over which 18 pedestals
were also built. The silos tank will be placed over these pedestals.
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Fig.3.3 Layout of Piles for Silos Tanks
IS: 2911 (part I Sec.2) – Indian Standard Code of practice for Design and
Construction of pile Foundations: Part I concrete piles, Section 2 – Bored Cast –in Situ piles
was referred in conjunction with other specifications during the entire design, construction
and installation work.
3.1 PROCEDURE
3.1.1 Test on soil
Standard penetration test was conducted earlier on the soil and the report was
provided by the consultants. The report showed that the N value was greater than 50
for depths greater than 10-13, on an average. This lead to a conclusion that bores for
piles has to be bored up to these depths plus around 10cm through the underlying
strata. The soil profile here indicated higher presence of red, clayey and sandy soils.
3.1.2 Levelling
Whole of the loads from tanks were to be transferred to the foundation area,
uniformly. For this the foundation had to be straight and level. This was achieved by
ensuring that the pile caps are all, in a same level. Levelling was done for assuring
that this requirement is met perfectly, using dumpy levels. Cutting and back filling
operations were then done, according to the requirement.
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3.1.3 Boring
Fig.3.4 Boring by DMC Method
As concluded from the standard penetration test, the piles are expected to be
10-13 meters long and that deep, boring was to be done. Boring was done by Direct
Mud Circulation (DMC) method. It was earlier ensured that the soil is capable of
safely withstanding the whole mechanical arrangements required for this method of
boring. In soft soils, a permanent liner has to be provided so as to withstand any
scouring of side walls. Even though the soil here wasn’t that soft, a permanent liner,
made of 6mm thick M.S. Sheets were provided. It was also ensured that the rigs had
the capacity of boring up to the required depth.
As the first step of boring, pile positions were marked according to the
drawings, with maximum precision possible. IS: 2911(part 1 /Sec.2) was referred for
permissible deviations. Then the boring rig was installed at such a position that the
chisel is ready to bore at the exact location of the pile to be cast. At this site, 4 rigs
were used, which are all run with petroleum fuels. A rig include an electric motor that
initiates work, three long pillars that can be set like a tripod, A pulley connected to the
motor via cable that can be released of load by means of a lever, A sharp edged chisel
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of high weight and required diameter etc. The chisel is like a thick metallic hollow
pipe that tapers out towards the bottom so that it can be connected to extra-long pipes
at the back, which are to be joined on boring deeper. The connecting pipes are also
hollow so that mud can be pumped through these pipes using an electric motor that
takes mud from a flushing chamber, nearby.
When the mechanical operations begin, the chisel is first lifted up and then
fallen down. This work is repeated by the chisel as bore starts developing at the pile
point. To make the soil soft, some water was initially poured. This water gets mixed
with the dugout soil and forms mud. The mud formed was taken through channels, to
the flushing chamber. The flushing chamber has two sections- one for the incoming
mud and the other for mud, mixed with Bentonite. The Bentonite is clay like mineral
that is extensively found in the Kuchh areas of Gujarat and Rajastan. Properties of
bentonite used was according to IS: 2911 (part 1/Sec.2). Bentonite is available in bags
at cheap rate. It’s like liquid in dynamic state and high viscous fluid in static state.
This property helps in preventing the actual soft soil walls of the bores from scouring
and falling in. This mud is circulated through the chisel to the bore and back to the
flush chamber through channel and hence called Direct Mud Circulation method.
When about half a meter of boring was done, a 6mm thick hollow metallic
cylindrical sheet was inserted so as to keep the bore diameter uniform. After each 2m
of boring, mud samples coming out from the bores were collected and tested. The
completion of boring can be understood when hard sounds are heard on hitting of
chisel on to the hard rock. The mud coming out of bore also indicates an approximate
depth of the bore. As a test if the boring has reached the hard strata, the depth of
further boring during a period of 1hour is noted. If it falls to be under 5-10 cm, hard
strata can be inferred and boring can be stopped. Some amount of pure water was then
pumped through the chisel so as to clean the bore and make it ready for the
installation of reinforcement and placing of concrete.
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3.1.4 Placing reinforcement
Fig.3.5 Reinforcement Units for Piles
By this time, the reinforcements as per designs were prepared aside. 20mm
diameter longitudinal bars along with lateral ties at designed spacing and other
specifications according to Relevant parts of IS: 2911 (part 1/Sec.2), were used. In
case of usage of two segments of reinforcement in the same place, they were lap
jointed by welding. As long as possible, lateral joints were avoided. Small circular
cement mortar elements called rollers were tied on to the outer parts of reinforcement
bars, which ensured required spacing from bore walls. They also facilitated smooth
and easy movement of reinforcement unit, on inserting it to the bore. The same rig as
that of the boring unit along with human support were used to place the
reinforcements correctly, which was done with extreme care.
3.1.5 Placing of concrete.
As the design, M30 Grade concrete had to be placed. The required amount of
concrete and its components were calculated before placing was started. The required
amount of concrete was prepared at the site in a mechanical mixer, on demand. The
mixed portion of concrete was poured very soon, concerned of the early setting of
concrete. For placing, Tromie pipe system was used. This system consists of hollow
metallic pipes of small diameter and considerable lengths, which could be connected
23
back to back using screw arrangements. It also contains a funnel of the same bottom
diameter as that of the pipes. The funnel had a key at its mouth. The pipes were
joined back to back and to one end, the funnel was connected. It was then inserted
into the bore using boring rigs, along with human effort. The tremie is so placed that
there is always a 30cm clear between bottom of it and end of the bore hole.
In such a position, the concrete mixer was placed very near to funnel so that
mixed concrete can be directly poured into the tremie. Initially, the mouth of the
funnel was closed using its key arrangement. Then, mixed concrete was filled in the
funnel. Then the key was suddenly opened and the concrete had fallen into the bore
through the tremie pipes, which resulted in the replacement of the mud at the bottom
of hole, by the incoming concrete. As the pouring procedure was repeated 2 or 3
times, the mud which was at the bottom of hole started rising and the mud at top
started overflowing out. Then, the tremie system was uplifted by some amount and
the pipe at the top was removed. Also, the tremie was moved up and down slightly for
helping compaction. During this procedure, it was mathematically ensured that the
pipe was still way inside the placed concrete, by around a meter so that no mud or air
gets inside the placed concrete.
On repeating this procedure, finally, the mud that was at the bottom of hole
came out, indicating that the hole is filled by concrete. The procedure was repeated
for better safety, until fresh concrete evolved out. As soon as the placing of concrete
was completed, the tremie was taken out and cleaned well.
3.1.6 Pile cap
The piles were constructed to the designed level of top of pile cap so that the
bottom portions of the pile would very strong. The top portion- around 1m, as
calculated- was then chipped off without affecting its reinforcements. Reinforcements
for the pile cap were placed over the piles, which results in strong intermingled
reinforcements. Pile caps of 1m depth were built over them on which pedestals were
constructed as a foundation for the tanks.
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4. ROAD WORKS FOR
GOVT. CYBERPARK, CALICUT
Cyber Park, a Government of Kerala organization planned in the lines of Techno Park
at Trivandrum and Info Park at Kochi to build, operate and manage IT park for the promotion
and development of investment in IT and ITES industries in Malabar region of Kerala has
been registered under the Societies Act 1860 on 28-01-09. The Cyberpark is expanding its
projects around 28 hectares of land in Nellikkode and Pantheerankavu village, Calicut. The
Govt. Expenditure towards the land acquisition for Cyberpark is estimated to be around 430
million INR and another 2.50 billion INR over the next two year for providing necessary
infrastructure and construction of buildings.
Fig.4.1 Land Development and Road works for Govt. Cyber Park, Calicut.
The road constructed at cyber park were a BMBC type Flexible road had a total coat
of 20.46 crore for road, drainage, and Reinforced Earth Wall etc. We were trained at this
project site on Sept. 30th 2013, with the help of Mr. Sandeep and The Project officer at Govt.
Cyber Park, Calicut, Mr. Viswanathan (Retd. Chief Engineer, PWD). The detailed
construction details which we gained from the project are explained below.
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4.1 LAND DEVELOPMENT
Fig.4.2 Earthwork at Cyberpark, Calicut.
There were some schedules and guideline was taken by the authorities for the total
construction of the project. The site chosen for the Cyberpark were a hill top and it was
covered with dense vegetation. Hence for the further construction the land were had to be
developed. The small jungles were cleared first and the uprooting of trees up to 30 cm depth
was done. This rubbish is shifted to a distance of 150 m outside the periphery of the proposed
area.
Earth work for all the soil except hard rock was done by means of Earthmovers. This
excavated soil is then transported to a distance within 5 km in Lorries. The levelling of
underlying soil is done after that. The depressions on the land are filled by using some of the
excavated soil. The soil consolidated with rollers and made a 15 cm layer. And watered and
ramming were done.
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4.2 FORMATION OF ROAD
The road work at Cyberpark Calicut were a BMBC Flexible pavement having
following layers from bottom to top, Sub Base, Wet Mix Macadam, Wearing Coarse,
Bituminous Macadam, Bituminous Concrete. The detailed specification of each layer is
explained below. Typical Road section is shown in fig. 4.4
4.2.1 GSB (Granular Sub Base)
The construction of granular sub base is done by providing close graded
materials (metal size: 53 - 9.5 mm = 0.64 m3, 9.5 – 2.36 mm = 0.25 m3 and 2.36 mm
= 0.38 m3). The mixing operation were done in a mechanical mix plant at OMC,
carried to site and spread in uniform layer with motor grader on prepared surface and
compacted with vibratory power roller to activate desired density. The GSB layer
provided in 20 cm thickness for whole road.
Fig.4.3 Applying GSB Layer using Aggregate Grader
4.2.2 WMM (Wet Mix Macadam)
Providing, laying and spreading and compacting graded stone aggregate
(metal size : 45 – 22.4 mm = 0.396 m3, 22.4 – 2.36 mm = 0.52 m3 and 2.36 mm - 75µ
= 0.396 m3) to wet mix macadam specifications including premixing the material with
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water at required OMC in the mechanical mix plant and carried the mixed material by
tipper to site, laid in uniform layer. Paved on well prepared sub-base and compacted
with vibratory roller to achieve desired density and thickness 25 cm.
4.2.3 WC (Wearing Course)
Providing and laying surface dressing as wearing course in single coat using
crushed stone aggregate of size 19 mm at 0.015m3 /m2 on a layer of bituminous binder
at 1.20 kg/ m2 laid on prepared surface and rolling with 8-10 tonne smooth wheeled
steel roller. The wearing Coarse thickness were 15 mm. Providing and applying tack
coat with bitumen emulsion using emulsion pressure distributor at the rate of 0.02 kg
per sqm on the prepared bituminous/granular surface cleaned with mechanical broom.
4.2.4 BM (Bituminous Macadam)
Providing and laying bituminous macadam of 50 mm thick with 100-120 TPH hot
mix plant producing an average out of 75 tonnes per hour using crushed aggregate
of40 mm nominal size 1.42 m3 premixed with bituminous binder over a previously
prepared surface with paver finisher to the required grade, level and alignment and
rolled to achieve the desired compaction. Providing and applying tack coat with
bitumen emulsion using emulsion pressure distributor at the rate of 0.30 kg per sqm
on the prepared bituminous/granular surface cleaned with mechanical broom.
4.2.5 BC (Bituminous Concrete)
Providing and laying bituminous concrete of 25 mm thick with 100-120 TPH batch
type hot mix plant producing an avg. output of 75 tonnes per hour using crushed
aggregate of size 19mm nominal size 1.46 m3 and filler 2 % of weight of aggregate,
premixed with bituminous binder at 5.4 to 5.6 per cent of mix and filler, transporting
the hot mix to work site, laying with a hydrostatic paver finisher with sensor control
to the required grade, level and alignment, rolling with smooth wheeled, vibratory and
tandem rollers to achieve the desired compaction.
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4.3 DRAINAGE DETAILS
In hilly areas, the drainage of rain water is faster and it discharges into nearby
depressions. The need for an efficient drainage system can, therefore, be hardly over
emphasized. The essential components of drainage system are: water collection catch pit at
roadside; connection of the catch pits to open/underground drains; and discharge of these
drains into an outfall. Since the rain water does not require any kind of treatment, so
generally the water is disposed of in any nearby nallah/river etc.
4.3.1 Drain/Com./Plum Duct
After the earth work were done for the drainage construction a layer of PCC is
provided on the proposed drainage line. The structural details are shown in fig. For
both drain duct and communication duct of length 60 cm a PCC layer of 1:5:10 0f 10
cm thick is provide and for plumbing duct of 75 cm a PCC of 1:4:8 of 10 cm thick is
provided. The three ducts were covered with RCC slabs of M20 grade. The covering
was only provided discontinuously for the later insertion of cables and pipes. Typical
view is shown in fig.4.5.
Fig.4.5 Drainage, Communication and Plumbing Duct, Cyberpark
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4.3.2 Catch pit
Fig.4.6 Catch pit Drainage Cyberpark, Calicut.
Water collection in the catch pits, usually covered by horizontal/vertical
gratings, is hampered as these gratings get covered with dead leaves/ rubbish. These
catch pits, which temporarily store the surplus water themselves get choked over time,
as dust/dirt/debris get deposited and choke their outlets to drains. The periodic
cleaning of these collection chambers is essential. There is a need to design and install
catch pits keeping in view the maximum rainfall intensity, duration of rainfall, the
expected surface run off and the capacity of the outlet of the catch pit so that the catch
pits do not overflow during high intensity rains. The location of catch pits should be
decided judiciously so as to permit future development and widening of road without
disturbing the storm water collection system. The design details of the catch pit are
shown in fig.4.7.
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4.4 REINFORCED EARTH WALL
Reinforced Earth is a composite material formed by the association of a frictional soil
and reinforcement strips. In concept, it is like reinforcing concrete; that is, it is an economical
means of improving the mechanical properties of a basic material, earth, by reinforcing that
material with another, steel. Concrete facing panels are used at the face of the reinforced
volume to prevent erosion of the backfill and to provide an attractive, finished appearance.
Fig.4.7 the RE Wall Constructed at Cyberpark, Calicut
Reinforced soil wall installation is the combination of quite a few simple procedures
like casting, curing, stacking, transporting of facia panel, excavation, earth filling layer,
compaction, facia panel erection and alignment, fixing of soil reinforcement (geogrid),
casting of coping/ barrier etc.
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4.4.1 Panel Casting
Precast concrete panel is one of the biggest advantages of this system as it
save lot of construction hassles along with time and money. Use of especially
designed/fabricated molds is required for this job as aesthetic and dimension of this
panel play an important role in overall performance of the reinforced soil wall.
Different size of panels is being used depending up on the geometry/ profile of the
structure, majority of panels is standard 1.5 x 1.5. Casting of precast panel involves
following activities.
Infrastructure set – up i.e. casting yard/ store/ batching plant/ laboratory etc.
Casting of panels i.e. molds fixing, placing accessories, concrete pouring etc.
Curing
Stacking and transportation.
4.4.2 Panel Erection
The ultimate manifestation of a reinforced soil structure depends largely on
the care taken in erecting and positioning facing elements. For this reason, particular
attention must be paid to the erection of facing elements and to the backfill placement.
In the installation of reinforced soil facia panel and the activities related to
construction of reinforced soil wall. The following major activities are involved.
Setting up the site. i.e. Excavation, Foundation treatment, Levelling pad etc.
Erection of facia panel i.e. placing and alignment
Earth Work i.e. filling and compaction of reinforced soil, retained soil and
filter media.
Reinforcement i.e. placing of geogrid and tightening
Installation of pavement fixture i.e. friction slab, crash barrier, railing, drain
etc.
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4.5 COMPOUND WALL
Fig.4.8 The Compound wall of Cyberpark, Calicut.
A well erected masonry boundary wall had provided throughout the periphery of the
Cyber Park. The standard specifications for the construction of the wall are following.
Excavation in ordinary rock and depositing on bank with initial lead up to 50m and
lift up to 1.5m including breaking clods, watering, ramming, sectioning of spoil bank,
stacking serviceable material for measurements and disposal of unserviceable material as
directed, filling back the sides of RR Masonry. Cement concrete were casted 1:4:8 using
40mm broken stone. Random Rubble masonry in cement mortar 1:6 for foundation and
basement of boundary wall. Laterite masonry using neatly dressed stones of size 35x20x20 in
CM 1:6 for bounder wall. For fixing angles and completing coping cement concrete 1:2:4
(M 15) using 20mm broken stones are used. Above this MS Angle iron for fencing post are
provided. Typical c/s of the masonry boundary wall has shown in fig.4.10.
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5. PILING WORKS FOR E.M.S. HOSPITAL
Construction works of the proposed 12crore worth E.M.S. Hospital at a 1.266 Acre
site at Perambra was the fourth concern of our training works, which we did on 01/03/2013,
with the help of site Engineer Mr.Nirmal. The works on progress at this site was mainly that
of piling. 100 piles had to be constructed at this site for transferring load from a 5 storied
building, uniformly over the ground, where hard strata was found at about 9-13 m depth, on
an average. Of the total 100 piles, about 82 were completed of work and 2 were on progress.
The piles were all of diameter 600, 700 or 900mm. Pile cap and superstructure works have
been started over some completed piles. Direct mud circulation method was used here for
piling, for which 2 rigs were employed.
5.1 SOIL TEST DETAILS
As the primary step, Standard Penetration Test (SPT) was conducted on the soil, so as
to obtain the soil profile and strength details. For this, 3 known points were selected at the
site, where bore holes were made, from which soil samples at different depths were collected
for testing. The locations of the bore holes were as shown in fig. 5.1. The test details which
include the soil profile and N values at different depths are shown in table. 5.1, 5.2 & 5.3.
Fig.5.1 Key Plan on Location of Bore Holes
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Table.5.1 Boring Log of Hole 1
Table.5.2 Boring Log of Hole 2
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Table.5.3 Boring Log of Hole 3
5.1.1 Recommendations
From the soil test details as presented in the above figures, it was inferred that
there’s no uniformity in soil profiles at different locations. Even though in BH2
medium hard laterite, which is capable of supporting the foundation of the proposed
structure, was available, it was missing at other locations. Since the proposed
structure was a 4 storeyed one with a possibility of additional floor later and since
hard and strong stratum was missing at other locations other than BH2, Shallow
foundation was not recommended for the structure. Piles resting on hard strata, which
were available at 9-13 m below, were recommended for foundation.
5.2 LEVELLING
Whole of the loads from the building were to be transferred to the foundation area
uniformly. For this the foundation had to be straight and level. This was achieved by ensuring
that the pile caps were all in the same level. The area was levelled using dumpy levels and it
was assured that this requirement is met perfectly. Cutting and back filling operations were
then done, according to the requirement.
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5.3 BORING
As concluded from the standard penetration test, the piles were expected to be 10-13
metres long and that deep, boring was done. Boring was done by Direct Mud Circulation
(DMC) method. It was earlier ensured that the soil is capable of safely withstanding the
whole mechanical arrangements required for this method of boring. In soft soils, a permanent
liner has to be provided so as to withstand any scouring of side walls. Even though the soil
here wasn’t that soft, a permanent liner, made of 6mm thick M.S.Sheets were provided. It
was also ensured that the rigs had the capacity of boring up to the required depth.
As the first step of boring, pile positions were marked according to the drawings, with
maximum precision possible. IS: 2911(part 1/Sec.2) was referred for permissible deviations.
Then the boring rig was installed at such a position that the chisel is ready to bore at the exact
location of the pile to be cast. At this site, 2 rigs were used, which were all run with
petroleum fuels. A rig include an electric motor that initiates work, three long pillars that can
be set like a tripod, A pulley connected to the motor via cable that can be released of load by
means of a lever, A sharp edged chisel of high weight and required diameter etc. The chisel
is like a thick metallic hollow pipe that tapers out towards the bottom so that it can be
connected to extra-long pipes at the back, which are to be joined on boring deeper. The
connecting pipes are also hollow so that mud can be pumped through these pipes using an
electric motor that take mud from a flushing chamber, nearby.
When the mechanical operations began, the chisel was first lifted up and then fallen
down. This work was repeated by the chisel as bore started to develop at the pile point. To
make the soil soft, some water was initially poured. This water got mixed with the dugout soil
and mud was formed. The mud formed was taken through channels, to the flushing chamber.
The flushing chamber has two sections- one for the incoming mud and the other for mud,
mixed with Bentonite. The Bentonite is clay like mineral that is extensively found in the
Kuchh areas of Gujarat and Rajastan. Properties of bentonite used was according to IS: 2911
(part 1/Sec.2). Bentonite is available in bags at cheap rate. It’s like liquid in dynamic state
and high viscous fluid in static state. This property helps in preventing the actual soft soil
walls of the bores from scouring and falling in. This mud was circulated through the chisel to
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The bore and back to the flush chamber through channel and hence called Direct Mud
Circulation method.
Fig.5.2 Bentonite Mixing Pit, EMS Hospital Construction, Perambra
When about half a metre of boring was done, a 6mm thick hollow metallic cylindrical
sheet was inserted so as to keep the bore diameter uniform. After each 2m of boring, mud
samples coming out from the bores were collected and tested. The completion of boring can
be understood when hard sounds are heard on hitting of chisel on to the hard rock. The mud
coming out of bore also indicates an approximate depth of the bore. As a test if the boring has
reached the hard strata, the depth of further boring during a period of 1hour is noted. If it falls
to be under 5-10 cm, hard strata can be inferred and boring can be stopped. Some amount of
pure water was then pumped through the chisel so as to clean the bore and make it ready for
the installation of reinforcement and placing of concrete.
5.4 REINFORCEMENT
By this time, the reinforcements as per designs were prepared aside. 20mm diameter
longitudinal bars along with lateral ties at designed spacing and other specifications
according to Relevant parts of IS: 2911 (part 1/Sec.2), were used. In case of usage of two
segments of reinforcement in the same place, they were lap jointed by welding. Care was
taken to avoid lateral joins at same levels. As long as possible, lateral joints were avoided.
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Small circular cement mortar elements called rollers were tied on to the outer parts of
reinforcement bars, which ensured required spacing from bore walls. They also facilitated
smooth and easy movement of reinforcement unit, on inserting it to the bore. The same rig as
that of the boring unit along with human support were used to place the reinforcements
correctly, which was done with extreme care. The reinforcement details of different piles are
shown in fig 5.3.
5.5 CONCRETING
As the design, M35 Grade concrete had to be placed. The required amount of concrete
and its components were calculated before placing was started.
The required amount of cement and thereby that of concrete was calculated as follows:
(For this case, a pile of diameter 900mm & depth 12.64m was considered.)
Volume of 1 pile = pr2h
= 3.14 *0 .452 *12.64
= 8.03 m3 of concrete per pile
Amount of cement per m3 of M35 concrete = 400 kg
No. Of bags = 400kg / 50kg
=8 bags of cement per m3 of M35 concrete
No. of bags of cement for 1 pile = 8.03m3 * 8 bags/m3
= 64.29 bags of cement per pile
The required amount of concrete was prepared at the site in a mechanical mixer, on
demand. The mixed portion of concrete was poured very soon, concerned of the early setting
of concrete. For placing, tremie pipe system was used. This system consists of hollow
metallic pipes of small diameter and considerable lengths, which could be connected back to
back using screw arrangements. It also contains a funnel of the same bottom diameter as that
of the pipes. The funnel had a key at its mouth. The pipes were joined back to back and to
one end, the funnel was connected. It was then inserted into the bore using boring rigs, along
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with human effort. The tremie is so placed that there is always a 30cm clear between bottom
of it and end of the bore hole.
In such a position, the concrete mixer was placed very near to funnel so that mixed
concrete can be directly poured into the tremie. Initially, the mouth of the funnel was closed
using its key arrangement. Then, mixed concrete was filled in the funnel. Then the key was
suddenly opened and the concrete had fallen into the bore through the tremie pipes, which
resulted in the replacement of the mud at the bottom of hole, by the incoming concrete. As
the pouring procedure was repeated 2 or 3 times, the mud which was at the bottom of hole
started rising and the mud at top started overflowing out.
Then, the tremie system was uplifted by some amount and the pipe at the top was
removed. Also, the tremie was moved up and down slightly for helping compaction. During
this procedure, it was mathematically ensured that the pipe was still way inside the placed
concrete, by around a metre so that no mud or air gets inside the placed concrete.
The mathematical procedure was as follows:
Ht. of pile with 1 bag of cement = 12.64 m / 64.29 bags
= 0.19 m rise of pile / bag
Ht. to be completed before removal of 1st pipe = 0.3 (Bottom clearance) +1 (Dipped
Length of tremie) + 0.8 (Length of top pipe)
= 2.3m of pile
Corresponding no. of bags of cement = 2.3m / 0.19m
= 12 bags of cement
i.e., after placing concrete corresponding to 12 bags of cement, the top most tremie piece
of 0.80m length can removed. Then the rest tremie system will be immersed in the
concrete by 1m length. This length can be considered for compaction.
The rest of the pipes were all 1.35m depth. So, each pipe could be removed after
addition of additional concrete, corresponding to (1.35/.19 =) 7-8 cement bags.
On proceeding, finally, the mud that was at the bottom of hole came out, indicating
that the hole is filled by concrete. The procedure was repeated for better safety, until fresh
concrete evolved out. As soon as the placing of concrete was completed, the tremie was taken
out and cleaned well.
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5.6 PILE CAP
Fig.5.4 PCC Layer over two piles.
The piles were constructed to the designed level of top of pile cap so that the bottom
portions of the pile would very strong. The top portion- around 1m, as calculated- was then
chipped off without affecting its reinforcements. Before casting Pile cap a combined PCC
layer of 100 mm thick is provided as shown in fig.5.3, on the top of two piles for providing a
hard levelled base surface for the pile cap construction. Reinforcements for the pile cap were
placed over the piles, which results in strong intermingled reinforcements. Pile caps of 1m
depth were built over them, over which the super structure was to be built. The reinforcement
details of 600 mm pile are shown in fig.5.6.
Fig.5.5 After construction of pile cap.
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6. SWIMMING POOL WORK AT Pe-Co-C,
PERINTHALMANNA
The Pe-Co-C (Perinthalmanna Co-operative Health and Recreation Centre) will be a
multi-sports facility that provides its users with various services. A first class fitness Centre,
two swimming pools both for adults and kids, life style center, indoor stadium etc. are
included in the construction of the Pe-Co-C. It is the first sports facility in Perinthalmanna
where families of all age groups have the options to expand their activities. The Pe-Co-C is
located on a hill top just 4 km away from Perinthalmanna town. The total cost estimated is 20
crore. It is supposed to be the best south Indian multipurpose indoor stadium, modern aquatic
club, sports village, courts of a range of events. These apart 3-star accommodations would
also be on offer.
The structural construction of restaurant, bath room, swimming pool 1 and 2 was
almost finished yet some finishing works has to be completed. After the completion of this,
the work for indoor stadium was planned to start. Our training date at this site was, Oct 3rd
2013, under the guidance of Mr. Jithesh. The site layout is shown in fig.6.2
Fig. 6.1 swimming pool 1 construction at Pe-Co-C
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6.1 CONSTRUCTION
The swimming pools constructing at Pe-Co-C is having rectangular shape of
dimension 25.60 m X 13.60 m for adult pool, and for kids pool its limited to 12.60 m X 6.60
m. The main difference in construction of this swimming pool from the pool at Nadakkavu
was, this swimming pool constructed above the original ground level, whereas at nadakkavu
a trench with pool dimension is excavated below the ground surface. Here after the full
construction of pool the ground level of four sides are to be elevated up to the pool’s top level
by backfilling. Due to the structural and load considerations this swimming pool has to
provide additional beams and columns.
The following aspects were taken into account during the load calculations process;
pool filling, alternating thermal loads, internal stress of the concrete pool shell with regard to
the reduction of shrinkage cracks, water pressure, support of other structural components
during construction, and loads resulting from normal operation of the pool.
6.1.1 Beams and Columns
Large amount of water pressure and weight of pool users are to be subjected
on the pool surface at normal operation condition. Due to design considerations and
for maximum safety 20 cm thick beams and columns are provided and slab of 20cm
thick was provided.10 mm mild steels are used for beam construction and they are
arranged with a spacing of 20 cm c/c. 10 mm mild steels are used for column
construction and they are arranged with a spacing of 15 cm c/c. The double mesh
method was used for slabs to withstand the water pressure. Stirrups of 8 mm thick
were provided for both beams and columns and are arranged with a spacing of 18 cm
c/c.
6.1.2 Concrete Slab
After the beam and column construction the slabs of pool dimension were
casted. In concrete construction of our site, a form was typically created using
plywood in the desired shape of the pool. The pool floor was poured first and the
walls are constructed on top of the floor, around a steel reinforcing web. The cavities
in the forms are filled with a high density concrete specifically designed and mixed
for pool construction. For our project M35 cast in-situ mix concrete were used. A
43
vibrating tool was utilized to fill any cavities and honeycomb voids and to make sure
that the steel reinforcing is completely encapsulated. Once the forms are removed and
the concrete is allowed to cure for a specified length of time, the pool can be tiled or
finished using another method.
6.2 FINISHINGS
The finishing work for swimming pools at Pe-Co-C is not yet started, but it was
scheduled to start after the work of restaurant. But some of the design and construction
features for final finish of swimming pool are planned at Pe-Co-C are given below.
6.2.1 Tile Selection
Tile and stone in swimming pools, fountains, spas, and water features is a very
appealing way to provide beauty and functionality. There are many types of tile and
stone in the world, but not all of them are suitable or functional in a submerged
installation. Choosing a tile or stone that is suitable for submerged applications is
critical to the long-term performance of the installation. Generally speaking, tile or
stone used in submerged installations must have a low absorption rate, a high
coefficient of friction, be freeze/thaw resistant (in cool climates), resistant to moisture
expansion, and chemical resistant.
6.2.2 Plumbing
Water in a swimming pool needs to circulate through a filtering system to
remove dirt and debris, and to evenly distribute the pool chemicals. For in ground
pools, fountains and water features most of the plumbing for the pool drains, pump
system and filters have to be installed prior to the pouring or spraying of the concrete.
The main drains are usually located in the lowest point of the pool, so the entire
contents of the pool will flow to the drains. The drain is tied into the pump system for
easy draining or fast circulation of the water in the pool.
6.2.3 Lights and Electrical
Like the plumbing, the lighting and electrical installation must be done prior to
the concreting. In our training site, swimming pool was constructed with underwater
lights. Five light fittings are provided on both long sides of the pool. These lights are
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essentially used so swimmers can see what they are doing at night and, to a lesser
extent, for aesthetic appeal. An incandescent light is sealed into a watertight fixture
which is located in a niche in the pool shell. The electric wire runs into the fixture
through a special seal which is designed to keep water away from the electrical
elements. Fiber optics is becoming more and more popular in pools because they do
not have to be embedded within the pool structure. Electrical work done in pools
before this time may be of sub-standard quality. Modern light fixtures are designed to
last for decades; however, poor water chemistry can weaken or degrade the fixture,
gasket and fasteners which hold it together. Failure to inspect these fixtures and
replace as necessary could result in costly damage to pool users or property.
6.2.4 Water Treatment
The presentation of a generally clean and tidy swimming pool is one reason
for following an appropriate cleaning programmed. However, good hygiene is also
most important to minimize the presence of harmful bacteria and other substances
which might pollute the water. Following are the major facilities planned in Pe-Co-C
for water treatment and disinfection.
The pool water disinfected with chlorine, bromine or by an ultraviolet light plus
hydrogen peroxide system.
The pH, total alkalinity, pool water turnover rate and cyanuric acid concentration
maintained.
The pool is to have a filtration system that provides a continuous circulation of
the pool water through the filter.
All water in the pool must pass through the filter as often as necessary to ensure
that the water is maintained in a clean and clear condition and in any event a
volume equivalent to the total volume of the pool at least.
Once in every six hours the swimming pool must be fitted with automatic dosing
and monitoring equipment that continuously analyses and controls the pH and
disinfectant levels in the pool water within the ranges.
The pool water clarity will be maintained as specified Standard.
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7. CONSTRUCTION OF BRIDGE
AT MUKKAMKADAVU
The long time wait of the civic society around the Mukkam region of Kozhikkode
district had ended up in the design of a complicated T- shaped bridge across the
Iruvanhippuzha River, near Mukkam. The special shaped bridge is first of its kind in Kerala,
which made it easier for the residents of Koodaranhi and Kodiyathoor regions to connect with
the Mukkam side, without being much affected by the higher rising flood at the region.
Designed by N.M.Salim associates and constructed by ULCCS Ltd., the bridge also is to have
a magnificent appearance. It provides a 11m roadway including footpaths, for the public.
Under the guidance of Mr. Miqdad N V and Mr. Akhil, This Bridge at Mukkamkadavu was
our industrial training site on Oct.4th 2013.
7.1 Architectural view of Mukkamkadavu Bridge
Approach roads supported by Reinforced earth wall were also a part of the project.
Due to their steep gradient the RE wall formation is only provided only for two shores. The
RE wall details were described by Mr. Riyas. The main structural portions of this particular T
Bridge was three arms and a central circle.
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7.1 STRUCTURAL DETAILS OF BRIDGE
7.1.1 Basic Components of Bridge
The component of the bridge is broadly grouped into
Foundation
Substructure
Superstructure
The foundation is different type viz., open foundation, well foundation, raft
foundation and pile foundation. The Mukkamkadavu Bridge was provided with pile
foundation. The substructure is the portion of the bridge structure such as pier and
abutments above the foundation unit and supporting the superstructure. It shall also
include returns and wing walls but exclude bearings. Superstructure is the portion of
bridge structure above the substructure level viz., deck slab/beam, hand rail, foot path
etc.
7.1.2 Standard definition
Clearance: Is the shortest distance between the boundaries at a specified
position of a bridge.
Free Board: Free board at any point is the difference between the highest
flood level after allowing for afflux if any, and the formation level of road
embankment on the approaches or top level of guide bunds at that point. Free
Board for high-level bridge shall in no case be less than 600 mm.
Linear Water way: is the width of waterway between the extreme edges of
water surface at the highest flood level measured at right angles to the
abutment faces.
Effective Linear Water way: is the total width of the waterway of the bridge
at HFL minus the effective width of obstruction.
Afflux: The rise in flood level of the river immediately on the upstream of the
bridge as a result of obstruction to the natural flow caused by the construction
of bridge and its approaches.
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Scour Depth: In natural stream, the scouring action of the current is not
uniform all along the bed width particularly at the bends and also round
obstructions to the flow eg. The piers of bridges there is deeper scour than
normal. The assessment of the scour depth is relevant for the design of bridge
foundations and protective works. Whenever possible such assessment should
be based on data made available from actual sounding taken at the proposed
bridge site or in its vicinity. Such soundings are being taken during
immediately after a flood before the scour holes have had time to silt up
appreciably. Necessary allowance shall be made in the observed scour depth
for increased depth for various reasons.
Vertical clearance: Adequate vertical clearance shall be provided in case of
all high level bridges which is usually the height from the designed HFL with
afflux to the lowest point of the bridge superstructure.
7.1.3 Components of Bridge
Fig.7.2 Super structures of Bridge pier
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7.1.3.1 Piles and Pile cap
The piles and pile caps constructed for this bridge were cast-insitu type.
Boring for the piles was done by Direct Mud Circulation (DMC) method. It was
ensured that the soil is capable of safely withstanding the whole mechanical
arrangements required for this method of boring. In soft soils, a permanent liner has to
be provided so as to withstand any scouring of side walls. Even though the soil here
wasn’t that soft, a permanent liner, made of 6mm thick M.S.Sheets were provided. It
was also ensured that the rigs had the capacity of boring up to the required depth.
Piling were done up to the hard strata and 50 cm more is digged to it. The average pile
depth in the site was 15 m. Total 4 piles were provided as foundation for each pier and
abutments, and each four piles were connected with a 1.5 m thick pile cap. The piles
and pile capes were casted in M35 grade concrete with OPC of 43 grades. The setting
time of concrete is having very importance in the bridge pile construction so a special
type admixture called Visconcrete were used while patching and casting, and it will
helps in controlling the setting time of concrete. The diameter of the piles for the
circle portion was of 1m and for the other parts were 0.9 m. The pile and pile cap
details were shown in fig.7.4 and 7.5.
Fig.7.3 Pile and Pile cap under Pier
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7.1.3.2 Piers and Abutments
Fig.7.6 Alignment of Piers and Abutments
A total of ten numbers of piers were constructed for the whole bridge. And
three numbers of abutments were located at three ends of bridge. The layout of piers
and were shown in Fig.7.6. The piers and abutments are cast in situ RCC M35 grade
concrete. The concrete was pumped to the mould by using machines, for the fast
construction. The piers and abutments were having 1.5 m diameter. The length of
each pier and abutment were different at due to the terrain undulations. The pier
length was large for the circular portion while it was small for piers near to shore area.
The cement used for the concrete preparation was OPC of 43 grades.
Fig.7.7 Piers of circular portion of bridge
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7.2 CONSTRUCTION OF RE WALL
Reinforced Earth is a composite material formed by the association of a frictional soil
and reinforcement strips. In concept, it is like reinforcing concrete; that is, it is an economical
means of improving the mechanical properties of a basic material, earth, by reinforcing that
material with another, steel. Stresses produced within the soil mass are resisted by the strips.
The stresses are transferred to the strips by friction. A Reinforced Earth structure constructed
using this material is shown as the “reinforced volume” in figure 1 below. Concrete facing
panels are used at the face of the reinforced volume to prevent erosion of the backfill and to
provide an attractive, finished appearance. The reinforced earth wall construction was one of
the main features of Mukkam Kadavu Bridge. The RE walls were provided at the starting of
arm1 and arm 2, for arm 3 the RR masonry is provided. The major parts of a RE wall
construction is, facia panels, geogrids and soil for backfilling. The RE wall panel of single
unit had about 980 kg of weight, and a face area of 2.1 m2.
7.2.1 Facia Panel
Fig.7.8 Facia Panels arranged for initial setting
Placing of mould in casting area should be on a leveled and well-compacted
surface. A layer of Brick bat/ GSB (100mm) and cement concrete (75mm0 shall cover
the entire casting and curing area. Proper drainage arrangement shall be made to avoid
stagnation of water at any location; arrangement can be made to collect drain water
51
and its reuse for the curing purpose. Mould shall be placed at a higher level for the
ease of work, Base plate of mould shall be evenly supported on a leveled firm
concrete base.
The concrete received from the batching plant were tested for field test, ideal
slump of concrete (considering a batch of 6 m3) is 30-40 mm, and in no case it shall
exceed to 60 mm. Mould was poured with concrete in 1-2 layers. Each layer were
compacted with a needle vibrator of 40 mm, additional tamping may be provided to
release entrapped air.M35 grade concrete were used for the making of facia panels.
De-molding of panel can be started after 4-5 hrs of casting depending up on
the ambient temperature/ humidity, amount of plasticizer etc. Remolding shall
carefully be watched to avoid any damage to corners of panel. If any crack is
appeared at the rear surface due to de-molding, shutter should be re-fixed
immediately, as crakes have a tendency to open up during which will result in
permanent rejection.
After panel casting, curing shall start as soon as possible. At the time when
panels are in casting area it shall be covered with canvas or plastic sheet, Hessia cloth
was recommended.
Panel can be lifted from the casting bed after 15-20 hrs.of casting, at the time of
lifting concrete should have attained at least 33% of its characteristics strength. The
panels shall be lifted from four points. The panels require minimum 14 days curing
before they can be erected at site. Curing time shifting of panels should be avoided.
Panel can be dispatched to site as soon as the curing period of panels is over.
A close coordination is required between site and casting yard to ensure that panels
are shifted to site are as per the erection program. Transportation can be made through
low bed trailer/ tipper/ truck etc. stability of individual panels must be ensuring before
sending any lot. First row of panels shall be stacked over the wooden sleepers and rest
of the rows to be placed over the wooden cube of 120x120x120. Not more than five
no. Of panel shall be put in one stack.
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7.2.2 Geogrid
There are mainly three type of geogrids are commonly available 80 kN, 60
kN, 40 kN. The first type geogrids were used at the bottom of RE wall, the geogrid
reinforcement is to be placed as per design and length of the project. The length of
reinforcement of geogrid to be laid can be ensure by snapping a line parallel to the
facia at a distance of reinforcement length from the back face of the facia panel. The
geogrid reinforcement should be laid perpendicular to the panel facia and wrapped
around the connector bars which are passed through the tie rods. The adjacent geogrid
should be placed butting each other.
7.9 The Geogrid used at Mukkamkadavu Bridge for RE wall formation.
Geogrid reinforcement should be properly tensioned and care should be taken
to ensure that there is no slack in reinforcement before placing of fill. If required the
geogrid can be nailed to the compacted fill prior to placement of succeeding layer of
fill material. The fill material placed over the geogrid should be spread in the
direction parallel to the facia panel. It should be ensured that no heavy machinery/
vehicle is allowed to move directly over the geogrid. The bed prepared to receive the
geogrid reinforcement should be properly leveled and have an even surface. The use
of cut pieces along the length is not permitted.
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8. ROAD WORK AT TIRUR
The construction work on coastal corridor linking vallarpadam with kozhikode is
started on March 2013. The corridor is expected to bring about tremendous development to
the coastal belt. The total project estimated to cost 2000 crore. It would lift the coastal area
between Kochi and Kozhikode to new level of development. The industrial, commercial, and
tourism development of Ernakulam, Thrissur, Malappuram and Kozhikkode district will
depend a great deal on the new corridor passing through the coast.
The first phase of the project “Strengthening, Widening and Extension of Tippu
Sulthan road” was our training site on Oct.5th 2013, under the guidance of Mr. Anuraj and
Mr. Naveen. The 4.5 km length road work had a total estimated cost of 17.75 crore, work
begun on March 21st 2013 and were planned to complete in one year.
Fig.8.1 Strengthening, Widening and Extension of Tippu Sultan Road, Tirur
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Road Construction activity in India has undergone significant changes over the last
one decade owing to the huge investments made and due to the adoption of state‐of‐the‐art
construction technology and design principles. Various types of bituminous binders and
several stabilizers are now available. The bituminous paving mixes as specified in MORTH
“Specifications for Road and Bridge Works”, Fourth Revision, 200128 are commonly used in
India. Some of these mixes have evolved since 1960s, an era when the present day hot mix
asphalt plants were not common and mixes were produced with small portable mixing plants
with limited aggregate heating, blending and mixing capabilities. The proliferation of
bituminous paving mixes as specified in the MORTH publication basically manifest the
constraints of non-availability of modern hot-mix plant besides likely cost reduction of lean
bituminous mixes.
It is well known that roads are generally constructed in embankment which comes in
the way of natural flow of storm water (from existing drainage channels). As, such flow
cannot be obstructed and some kind of cross drainage works are required to be provided to
allow water to pass across the embankment. There are numbers of cross drainage works are
practiced in India in pavement works, but box culverts are not common in those. One of the
interesting fact for us to work at Tirur was the use of box culverts as cross drainage, and it
were first time in Malabar region.
Box culvert has many advantages compared to other drainage works. The box is
structurally strong, stable and safe and easy to construct. The main advantage is, it can be
placed at any elevation within the embankment with varying cushion which is not possible
for other type of culverts. It does not require separate elaborate foundation and can be placed
on soft soil by providing suitable base slab projection to reduce base pressure within the safe
bearing capacity of foundation soil.
The design specifications for the flexible road, Tippu Sulthan were based on the
current Indian Roads Congress Specifications and recommended codes of practice, and
ministry of Roads Transport and highways as per IRC specifications.
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8.1 CONSTRUCTION OF PAVEMENT
Structural strength is the primary purpose of most bituminous mixes except those used
in very thin surfacing. The objective is to disperse appropriately the dynamic and static
effects of traffic wheel loads to the underlying pavement layers such as bituminous/crushed
stone base course. For low volume roads only a granular base and a bituminous wearing
course may suffice based on structural requirements. Normally, lower layers of base courses
including those of bituminous base courses (as provided in developed countries) should have
desired stiffness characteristics to act as good foundation, which should be effective in
dispersing the traffic loads to the lower layers. The top layers of bituminous binder courses
should have adequate stiffness to resist rutting coupled with the flexibility to be effective in
re-bounding. The flexibility characteristics should, therefore, increase when going from
bottom to upwards layer. The Tippu Sulthan road was a BMBC, Flexible road. The road
constructed were possessed the following layers, from bottom to top, sub grade, sub base, wet
mix macadam layer, dense grade bituminous macadam, bituminous concrete, bituminous
macadam. The details of development of these structural layers are explained below.
Strengthening, Widening and Extension of the Tippu sulthan road were done
simultaneously. The existing road had a width of 10 m, additional width of 5 m were
widened. For this purpose a suitable trench of required depth and 5 m width was excavated
along the side of existing road. At the location of bus bay the 5 m width is scaled in to 7-8 m
for the future construction of bus stops. After the trench formation the bottom surface soil
inside the trench was loosened, watered and compacted for about 15 cm depth. The
compaction was done by roller.
Fig.8.2 Widening of Tippu Sulthan road, Tirur
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8.1.1 Subgrade
Because of the presents of Arabian Sea at near, the natural earth surface at
Tirur was covered by sand, and no soil is found out during the widening and
excavation process. Due to this reason a layer of soil sub grade had provided for more
strength and stability. Hence a 30 cm layer of red sandy soil is applied in two layers,
with a 20 cm maximum layer thickness.
Fig.8.3 Red soil layer as Sub grade, Tippu Sultan Road
8.1.2 GSB (Granular Sub Base)
Fig.8.4 Applying GSB Layer over Subgrade, Tirur
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Sub bases serve a variety of purposes, including reducing the stress applied to
the sub grade and providing drainage for the pavement structure. The granular sub
base acts as a load-bearing layer, and strengthens the pavement structure directly
below the pavement surface, providing drainage for the pavement structure on the
lowest layer of the pavement system. However, it is critical to note that the sub base
layer will not compensate for a weak sub grade. Sub grades with a CBR of at least 10
should provide adequate support for the sub base.
As the granular sub base provides both bearing strength and drainage for the
pavement structure, proper size, grading, shape, and durability are important attributes
to the overall performance of the pavement structure. Granular sub base aggregates
consist of durable particles of crushed stone or gravel capable of withstanding the
effects of handling, spreading, and compacting without generation of deleterious
fines.
The GSB layer provided for Tippu Sulthan road had a thickness of 30 cm after
compaction, and this thickness is applied in 2 layers of GSB, the maximum layer
thickness were limited to 20 cm. The spreading and compaction of GSB were carried
out by Aggregate grader and Road rollers.
8.1.3 WMM (Wet Mix Macadam)
Wet mix macadam construction is an improvement over the conventional
water bound macadam providing speedy and more durable construction. It differs
from the water bound macadam in that graded aggregates and granular materials are
mixed with predetermined quantity of water in accordance with the specifications to
form dense mass which is spread and wiled to approved lines, grades and cross-
section to serve as pavement courses.
The thickness of single compacted wet mix macadam layer was limited to 15
cm. And a WMM layer of thickness 25 cm is provided for the 5 m wide road.
After construction of the top WMM layer immediate sealing with bituminous
surfacing is done at site.
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8.1.4 DBM (Dense Graded Bituminous Macadam)
The dense graded bituminous macadam was applied on the top of WMM, with
a thickness of 15 cm after compaction of road rollers. At Tirur, This was applied in 2
layer thickness of single layer were fixed to be 7.5 cm.
The bitumen for DBM shall comply with the Indian Standard Specifications
for viscosity graded bitumen, IS: 73 modified bitumen complying with IS: 15462 or
as otherwise specified in the Contract. Guideline for selection of viscosity graded
bitumen and modified bitumen is in table 7.1 and table 7.2 respectively. The use of
modified bitumen is recommended for very heavy traffic roads in very hot climate.
Table 8.1 Guideline for selection of viscosity graded (VG) Paving bitumen’s
Based on Climatic Conditions.
Highest Daily Mean Air Temperature, oc
Lowest Daily Mean
Air Temperature, oc
Less than 20 oc 20 to 30 oc More than 30 oc
More than -10 oc VG-10 VG-20 VG30
-10 oc or lower VG-10 VG-10 VG-20
Table 8.2 Selection Guideline for Grade of Modified Bitumen
Lowest Daily Mean Highest Daily Mean Air Temperature, oc
Air Temperature, oc Less than 20 oc 20 to 30 oc More than 30 oc
Grade Of Modified Bitumen
More than -10 oc PMB/NRMB 120
CRMB 50
PMB/NRMB 70
CRMB 55
PMB/NRMB 40
CRMB 60
-10 oc or lower PMB/NRMB 40
CRMB 50
PMB/NRMB 120
CRMB 55
PMB/NRMB 70
CRMB 50
PMB = Polymer modified bitumen
NRMB = Natural rubber modified bitumen
CRMB = Crumb rubber modified bitumen
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The dense flexible macadam (DBM) is specified for use as a base course
and/or binder course. The Coarse aggregate used for DMB were consist of clean
crushed rock, crushed gravel or other hard material retained on 2.36 mm sieve. For
the existing road the DBM of 7.5 cm thick is applied, at this level the newly
constructed road as well as the existing road where been in same level.
8.1.5 BM (Bituminous Macadam)
Bituminous Macadam (BM) is an open graded, permeable, and recipe type
mix produced without any quality control on its volumetric or strength (stability). The
primary problem with the BM mix is that being very open graded, it is highly
permeable and therefore will trap moisture or water. BM and SDBC were developed
several years ago, when conventional hot mix plants were not common. At that time,
hot mixing was done in small portable plants or concrete mixers in which much fine
aggregate could not be used due to limitations of the available heating and mixing
equipment. Now, good hot mix plants are normally available.
For Bituminous Macadam, the bitumen content for premix should be 3 to 3.5
per cent by weight of total mix except otherwise directed. The composition of
Bituminous Macadam should conform to IRC Specifications. The manufacturing and
rolling temperature limited to 155-170 oc. In our training site BM is applied with a
average thickness of 10 cm.
8.1.6 BC (Bituminous Concrete)
Above the 15 m wide road a BC layer of 4 cm thick is provided, because
bituminous macadam is a highly permeable mix and promotes rutting. Use of
Bituminous Macadam a very popular mix at present may be deleted and substituted
with DBM because it is finally cost effective and better performing. Similarly, use of
Semi-dense Bituminous Concrete is also not considered to be allowed in the
specifications. It suffers from “pessimum” voids, which have potential to trap water
resulting in moisture damage. It should be substituted by Bituminous Concrete as it is
better performing and cost effective. It is estimated that after finishing the complete
road work the height of the road may rise 19 cm from the initial road level.
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8.2 CONSTRUCTION OF CROSS DRAINAGE WORKS
It is essential that adequate provision is made for road drainage to ensure that a road
pavement performs satisfactorily. The main functions of a road drainage system are:
To prevent flooding of the road and ponding on the road surface
To protect the bearing capacity of the pavement and the sub grade material
To avoid the erosion of side slopes
Road surface drainage is done by kerbs and gullies are commonly used in urban areas
and in rural embankment conditions. Surface water flows over the pavement to a kerb at the
edge of the road and is collected in gullies which are connected to longitudinal carrier drains
set within the road verge. The carrier drain may be a sealed pipe for the collection of surface
water only (separate system), or a perforated or open jointed pipe may be used in order to
convey both surface water and subsoil water to the outfall (combined system). For the
removal of rain water from the road surface a camber of 2.5 cm vertical to every 1m
horizontal is provide for Tippu Sulthan Road. If this collected water has to be transferred
from one side of the road to another, suitable cross drainage work has to be provided.
8.2.1 Pre-cast Box Culverts
In the construction of new roads it is frequently necessary to culvert existing
watercourses passing across the line of the roadway. The most common materials
used for new culverts include concrete pipes, concrete box sections, and corrugated
steel pipes and arches. Materials used for older culverts include brick, masonry and
cast iron. At our training site Pre-cast Box culverts units were used. Total of 12
culverts were needs to provide for the t 4.5 km road, two of them were for convey
cables and 10 Nos. for drainage. The cable duct had inside size of 0.75m X 0.75m and
for the drainage 1m x 1m standard boxes were used. For the complete crossing of a
single culvert, about 16 pre-cast units of box culverts were required.
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Fig.8.6 Pre-cast Box Culvert Construction, Tippu Sulthan Road, Tirur.
Pre-cast construction means that traffic may use the installation immediately
after placing and backfilling whereas in-situ construction will require a period for
curing prior to stripping forms ready for use. Due to their ability to tolerate heavy
wheel loads even with no overfill in place, precast box culverts are superior to most
alternative systems which require compacted overfill in place before loading is
applied.
Fig.8.7 Pre-cast Box Culvert Units Tippu Sulthan Road, Tirur.
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Box culverts are normally designed for the standard highway vehicle loads or
railway load requirements bridge design code, as appropriate for the application.
However they can also be used in many non-standard applications and can be
designed to carry loads well in excess of normal highway loading. It is important to
note that construction considerations on site may require that heavy equipment must
travel over box culverts before soil cover is placed. This can result in loading
conditions more severe than those expected in service.
8.2.1.1 Design and Detailing
Box culverts are generally designed and detailed in accordance with the Box
Culvert Association Standard Specification which covers materials, manufacturing
tolerances, external loading design and detailing standards. Box culverts carrying
highway loading or railway loading are designed to current standards and
specification as stipulated by the client. For the construction of Tippu Sulthan road the
concrete used for the construction of each single units of box culverts was RCC of
grade M35 in 1:1.5:2.79 mix ratio. 1m x 1m box culverts had a weight near to 2.5
tonnes. The reinforcement details of the culvert have shown in fig.
8.2.1.2 Surface loading and Fill depth
Loading applied at the ground surface and weight of fill material produce a
combination of vertical and horizontal forces on the box culvert. Surface loading may
be specified as a standard loading type, equivalent uniform loading or individual
wheel loads. The critical load on a culvert can occur at minimum or maximum fill.
Each enquiry for a culvert should state the minimum and maximum fill depth and the
amount or type of surface loading. It is recommended that the minimum fill depth
should be not less than 200mm or one fifteenth of the internal width of the culvert if
this is greater.
8.2.1.3 Bedding, Laying and Backfilling
Excavation can be kept to a minimum with only nominal working space
required on each side of the box culvert. When working in trenches the normal
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requirements for health and safety must always be observed. The base of the trench
should be uniformly prepared before laying a 200mm bedding of compacted granular
material over the full width of the trench. A surface blinding of the fine material will
assist levelling. Local packing’s are subject to settlement and should not be used. As
an alternative to granular bedding a concrete blinding layer is sometimes preferred to
protect the formation or to allow a faster rate of laying the culverts. A layer of
unreinforced concrete approximately 75mm thick on a trench bottom which has been
well prepared to provide a uniform support is generally sufficient. . In our training site
before placing these culvert units a layer 20 cm, PCC of grade M15 were provided for
making a leveled hard bed surface. A culvert line is usually laid directly on the
bedding starting from the downstream end with the sockets facing upstream, to
receive the next culvert. The trench should be backfilled as soon as possible after the
culvert has been laid and it should be filled evenly on each side of the trench.
Backfilling should continue in 200mm compacted layers to reach the required depth
of cover.
8.2.1.4 Jointing
The boxes were constructed with an inward edge grip of 10 cm for the
interlocking of one box to another. The culvert sections generally have rebated joints
and can be laid open, or sealed using pre formed strips and/or pointing materials.
Reference should be made to the jointing material manufacturer’s specification and
recommendation for use of the product. A system using preformed strip within the
joint is most commonly used. When the strip is bitumen based the joint faces should
be cleaned, primed and allowed to dry. The strip is then applied to the internal corner
of the socket just before the culvert is laid in the trench. Joints are closed to a nominal
gap by pulling against previously laid culverts with an applied load of approximately
one tonne per metre of strip plus about half of the weight of the culvert unit to
overcome base friction, less if the unit is suspended from the crane whilst jointing.
Heat may be required to soften the strip when working at low temperature. When the
box culvert is of sufficient size for access, it can be pointed internally with an
elastomeric or bitumen based material using a suitable primer. At Tirur while
construction the joints are bonded with “Nitrobond PC40”-Fosroc-epoxy. Not all
methods of jointing, however, should be expected to be completely watertight.
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8.3 CONSTRUCTION OF RETAINING WALL
The retaining walls are structures designed to restrain soil to unnatural slopes. They
are used to bound soils between two different elevations often in areas of terrain possessing
undesirable slopes or in areas where the landscape needs to be shaped severely and
engineered for more specific purpose like hillside farming or roadway overpasses. At our
training site the terrain were not been in proper level at all portions, due to these undulations
and slopes, a Random Rubble Retaining wall had provided at these portions of the road. The
details of the same is shown in fig.8.8 the specification for this particular RR Retaining wall
are as follows.
Weep holes using 50 mm dia. PVC pipe to be provided at one per sq.m. The entry
point of weep holes to be covered with nylon mesh tied with nylon rope to avoid entry
of silt.
One bond stone shall be provided for every 0.50 sqm. of the area of wall surface of
the random rubble and dry rubble.
All bond stones shall be marked suitably with paint, bond stones running right
through the thickness of the walls shall be provided in walls up to 60 cm thickness.
For wall thickness above 60 cm a set of two or more bond stones overlapping each
other by at least 15 cm shall be provided in a line from face of the wall to the bake.
Where bond stones of suitable length are not available precast cement concrete block
of 1:3:6 mix (1 cement : 3 coarse sand : 6 graded stone aggregate 20mm normal size)
of cross section not less than 400 sq.cm and length equal to the thickness of wall shall
be used in lie of bond.
Expansion joints to be provided at every 25 m.
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9. CONCLUSION
The Industrial training we had undergone at various construction sites gave us
awareness about the details of construction. The study of various proposed civil structures
like buildings, roads, bridges, swimming pools etc. were done. Different stages of
constructions, modern technologies and materials used etc. were observed. Structural design,
architectural design safety measures, electrical and plumbing works etc. were noteworthy.
The aesthetics and structural design were the best.