brief theory of signature bridge
TRANSCRIPT
Summer training Report on
Construction of Signature Bridge
Submitted as partial fulfillment for the award of
BACHELOR OF TECHNOLOGY
DEGREE
Session 2015-16 in
Civil Engineering
By
PRAVIN KUMAR GAURAV
1203200077
Under the guidance of Mr. VISHWANATH SINGH
ABES ENGINEERING COLLEGE, GHAZIABAD
AFFILIATED TO
UTTAR PRADESH TECHNICAL UNIVERSITY, LUCKNOW
Summer Training Report on
Construction of Signature Bridge
Submitted as partial fulfillment for the award of
BACHELOR OF TECHNOLOGY
DEGREE
Session 2015-16 in
Civil Engineering
By
PRAVIN KUMAR GAURAV
1203200077
Under the guidance of Mr. VISHWANATH SINGH
ABES ENGINEERING COLLEGE, GHAZIABAD
AFFILIATED TO
UTTAR PRADESH TECHNICAL UNIVERSITY, LUCKNOW
Student’s Declaration
I hereby declare that the work being presented in this report
entitled “CONSTRUCTION OF CABLE STAYED BRIDGE
(SIGNATURE BRIDGE)” is an authentic record of my own work
carried out under the supervision of Mr.
“Mr. VISHWANATH SINGH”
The matter embodied in this report has not been submitted by me for
the award of any other degree. Dated Signature of student
Name: - PRAVIN KUMAR GAURAV
Department: CIVIL ENGINEERING
This is to certify that the above statement made by the candidate is correct to the best of my knowledge.
Signature of HOD
Name: - Dr. T. Vishalakshi
Date
ACKNOWLEDGEMENT
I would like to thank Delhi tourism and transport Development Corporation. for giving
me this invaluable opportunity to learn so much practical knowledge which would have
impossible to learn through only looking at images from textbooks. I have gained
invaluable insights into how construction of any superstructure is handled and how
any difficulty which comes in between is tackled. Apart from technical knowledge, I
have gained insights into Construction management, Efficient Man-power
management and lots of other things.
I would like to thank Mr. Vishwanath singh (Project Manager, DTTDC) and special
thanks to Mr. E.Ahmed (Executive engineer, CPWD Training institute) for providing
me this opportunity and giving me valuable support and teaching me values and ethics
of Civil Engineering and specially bridge principles. Also I would like to thank Mr.
Rajesh Chauhan (Site in Charge) and Mr. Sunil Kumar (superintendent Engineer)
for guiding me throughout the project and without whom this training would have been
impossible. Also I would like to thank Mr. R.K.Gupta (Assistant Engineer) for giving
me invaluable information and knowledge into construction processes.
In whole training I was helped by so many Engineers, Supervisors and everyone, it
will impossible to take everyone’s name. In all, I thank DTTDC Family for this
Invaluable opportunity and helping me out in any difficulty however big or small it may
be.
Last but not least, I would like to thank Dr. V. K. Gupta (executive engineering) for
arranging this training and who always have been supporting person for not only me
but for whole department.
PRAVIN KUMAR GAURAV
1203200077
B.TECH
LIST OF CONTENT 1. INTRODUCTION ................................................................................................. 1
2. DESCRIPTION OF PROJECT............................................................................. 2
3. SITE LAYOUT ..................................................................................................... 3
4. MATERIALS USED AT A CONSTRUCTION SITE .............................................. 4
Settling Of Cement ........................................................................................... 5
Initial and final setting time of cement............................................................... 5
Storage of Cement ........................................................................................... 6
Coarse Aggregate ............................................................................................ 6
Fine Aggregate ................................................................................................. 7
5. REINFORCEMENT ............................................................................................. 7
TERMS USED IN REINFORCEMENT ............................................................. 9
6. Shuttering and Scaffolding ................................................................................. 10
7. CLEANING AND TREATMENT OF FORMS ..................................................... 11
Verticality of the Structure .............................................................................. 12
STRIPPING TIME OR REMOVAL OF FORM WORK .................................... 13
Concrete Production ....................................................................................... 13
Properties of Concrete.................................................................................... 14
Curing of Concrete ......................................................................................... 14
8. BATCHING PLANT ............................................................................................ 15
9. FOUNDATIONS ................................................................................................. 17
Well foundation ............................................................................................... 17
Components of well foundation ...................................................................... 17
Sinking of Well Foundation ............................................................................. 18
LOAD APPLICATION ..................................................................................... 20
SINKING PROCEDURE ................................................................................. 20
Measures for rectification of tilts and shifts ..................................................... 21
10. Open foundation/Pile foundation .................................................................... 23
Pile Classification by Construction Method ..................................................... 23
Pilling Steps .................................................................................................... 27
11. PLACING OF GIRDERS ................................................................................ 29
12. QUALITY ASSURANCE/ QUALITY CONTROL ............................................. 30
13. TESTS CONDUCTED .................................................................................... 35
Test Conducted on Fresh Concrete ............................................................... 35
14. CONCLUSION ............................................................................................... 41
LIST OF FIGURES:
Figure 1 Artistic view of Signature Bridge ................................................................... 1
Figure 2 Schematic diagram ...................................................................................... 2
Figure 3 Plan of pile ................................................................................................... 4
Figure 4 Plan of pier ................................................................................................... 4
Figure 5 Tying of reinforcement bar ........................................................................... 7
Figure 6 Pile cap reinforcement ................................................................................. 7
Figure 7 Cover blocks .............................................................................................. 10
Figure 8 Formwork of pier and false wall .................................................................. 11
Figure 9 Curing of well steining ................................................................................ 14
Figure 10: Curing of well foundation ......................................................................... 15
Figure 11: Batching plant ........................................................................................ 16
Figure 12: Schematic diagram of well foundation ..................................................... 17
Figure 13: Jackdown of well foundation ................................................................... 19
Figure 14: Gripper rods anchored in ground ............................................................ 20
Figure 15 Power pack .............................................................................................. 20
Figure 16: Formation of Slumps inside the well ........................................................ 21
Figure 17: Rectifying tilt by eccentric loading ........................................................... 22
Figure 18: Rectifying by pushing well jacks .............................................................. 22
Figure-19:- Well staining……………………………………………………………… …23
Figure 20:- Pile Driving………………………………………………………………….…27
Figure 21:- HSFG 8.8 Grade bolt…..…………………………………………………….29
Figure 22: Placement of steel girder1s ..................................................................... 31
Figure 23: Test and their Frequency ........................................................................ 37
Figure 25: Compression testing machine ................................................................. 40
Figure 26: Silt content test ........................................................................................ 41
1. INTRODUCTION
Figure 1 Artistic view of Signature Bridge
India’s first “Signature Bridge” being constructed across the Yamuna at Wazirabad
promises to be a great attraction of Delhi. An ambitious project of the Delhi tourism, the
cable-stayed bridge will link National Highway number one near existing T-point at
Wazirabad on Western bank and Marginal Bund Road at Khajuri Khas on eastern bank of
the river Yamuna, thus connecting North Delhi with East Delhi.
With a length of about 575 meters and a height of 154 meters the proposed Signature
Bridge would have a bow-shaped pylon in the middle. Two high towers will be there to
provide double cable support in the inner periphery of the carriageway. Equipped with eight lanes, this engineering masterpiece will have 1.2 meter wide central
verge, space for anchoring cables, maintenance walkway and crash barrier on either side
of the central verge. The deck will be composite (steel and concrete) while pylon will be in
steel.
Once operational the Signature Bridge will eventually improve access between North and
west Delhi for the commuters, who have to pass through the narrow lane on the present
bridge in Wazirabad, leading to heavy traffic jam in the peak hours. Also, to facilitate the
movement of vehicular traffic new express lanes will be constructed to connect Ring Road
with the bridge.
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2. DESCRIPTION OF PROJECT:
PROJECT NAME: Signature Bridge(Yamuna bridge at Wazirabad)
CLIENT: Delhi Tourism & Transportation Development Corporation Ltd.
AGENCY: J.V. of M/s Gammon India & Construtora Cidade, Tensacciai
DESIGN CONSULTANT: J.V. of M/s. Schlaich Bergermann Und Partner, Construma
Consultancy pvt ltd. Mumbai
PROOF CONDULTANT: J.V. of M/s. Systra, Virlogeux & Tandon Consultants.
SUB-CONSULTANT: Ratan J.Batliboi Architects, Mumbai, Department of
EARTHQUAKE ANALYSIS: - IIT Roorkee & structural engg. Research center, Chennai.
LISENCE NO: CLA/c/13N/10
PERIOD OF CONSTRUCTION: 20/3/2013 to 19/12/2016 (ESTIMATED)
COST OF PROJECT: 1591 crore (revised)
TOTAL LENGTH : 575m (8 LANES)
PYLON HEIGHT: 154m (5400 ton)
FOUNDATIONS: 6 open and 18 well foundations
ADDITIONAL WORK: eastern and western approaches
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Figure 2 Schematic diagram
3. SITE LAYOUT A badly planned and untidy site is the underlying cause of many accidents resulting from
falls of material and collisions between workers and plant or equipment. Space constraints,
particularly in urban work sites, are nearly always the biggest limiting factor and a layout
which caters best for the safety and health of workers may appear to be difficult to reconcile
with productivity. Proper planning by management is an essential part of preparation and
budgeting for the safe and efficient running of a construction operation.
Before work even begins on site, thought needs to be given to: a. The sequence or order in which work will be done and to any especially hazardous
operations or processes.
b. Access for workers on and around the site. Routes should be free from obstruction
and from exposure to hazards such as falling materials, materials-handling equipment
and vehicles. Suitable warning notices should be posted. Routes to and from welfare
facilities need equal consideration. c. Routes for vehicular traffic. These should be “one way “as far as practicable. Traffic
congestion prejudices the safety of workers, especially when impatient drivers unload
goods hurriedly.
d. Storage areas for materials and equipment. Materials need to be stored as close as
possible to the appropriate workstation, e.g. sand and gravel close to the cement-
batching plant, and timber close to the joinery shop. If this is not practicable, it is
important to schedule the arrival of materials. e. The location of construction machinery. This is usually dependent on operational
requirements so that tower cranes are subject to constraints such as their radius of
operation, and pick-up and unloading points.
f. The location of trade workshops –these are not usually moved after they are built. g. The location of medical and welfare facilities. On large sites sanitary facilities for both
sexes should be provided at several locations.
h. Artificial lighting at places where work continues or workers pass after dark. i. Site security. j. Arrangements to keep the site tidy and for the collection and removal of waste.
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Figure 3 Plan of pile Figure 4 Plan of pier
k. The need for low-voltage electric power supplies for temporary lighting, portable tools and equipment.
4. MATERIALS USED AT A CONSTRUCTION SITE
Cement Portland cement is composed of calcium silicates and aluminates and aluminoferrite It is
obtained by blending predetermined proportions limestone clay and other minerals in small
quantities which is pulverized and heated at high temperature –around 1500 deg.
centigrade to produce ‘clinker’ .The clinker is then ground with small quantities of gypsum
to produce a fine powder called Ordinary Portland Cement (OPC). When mixed with water,
sand and stone, it combines slowly with the water to form a hard mass called concrete.
Cement is a hygroscopic material meaning that it absorbs moisture in presence of moisture
it undergoes chemical reaction termed as hydration. Therefore cement remains in good
condition as long as it does not come in contact with moisture. If cement is more than three
months old then it should be tested for its strength before being taken into use. The Bureau of Indian Standards (BIS) has classified OPC in three different grades The
classification is mainly based on the compressive strength of cement-sand mortar cubes
of face area 50 cm2 composed of 1 part of cement to 3 parts of standard sand by weight
with a water-cement ratio arrived at by a specified procedure. The grades are (i) 33 grade (ii) 43 grade
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(iii) 53 grade The grade number indicates the minimum compressive strength of cement sand mortar
in N/mm2 at 28 days, as tested by above mentioned procedure. Portland Pozzolana Cement (PPC) is obtained by either intergrinding a pozzolanic material
with clinker and gypsum, or by blending ground Pozzolana with Portland cement.
Nowadays good quality fly ash is available from Thermal Power Plants, which are
processed and used in manufacturing of PPC.
Settling Of Cement
When water is mixed with cement, the paste so formed remains pliable and plastic for a
short time. During this period it is possible to disturb the paste and remit it without any
deleterious effects. As the reaction between water and cement continues, the paste loses
its plasticity. This early period in the hardening of cement is referred to as ‘setting’ of
cement.
Initial and final setting time of cement
Initial set is when the cement paste loses its plasticity and stiffens considerably. Final set
is the point when the paste hardens and can sustain some minor load. Both are arbitrary
points and these are determined by Vicat needle penetration resistance. Slow or fast setting normally depends on the nature of cement. It could also be due to
extraneous factors not related to the cement. The ambient conditions play an important
role. In hot weather, the setting is faster, in cold weather, setting is delayed Some types of
salts, chemicals, clay, etc if inadvertently get mixed with the sand, aggregate and water
could accelerate or delay the setting of concrete.
Storage of Cement
It needs extra care or else can lead to loss not only in terms of financial loss but also in
terms of loss in the quality. Following are the don’t that should be followed -
a) Do not store bags in a building or a go down in which the walls, roof and floor are
not completely weatherproof.
b) Do not store bags in a new warehouse until the interior has thoroughly dried out.
c) Do not be content with badly fitting windows and doors, make sure they fit
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properly and ensure that they are kept shut.
d) Do not stack bags against the wall. Similarly, don’t pile them on the floor unless
it is a dry concrete floor. If not, bags should be stacked on wooden planks or
sleepers.
e) Do not forget to pile the bags close together
f) Do not pile more than 15 bags high and arrange the bags in a header-and-
stretcher fashion.
g) Do not disturb the stored cement until it is to be taken out for use.
h) Do not take out bags from one tier only. Step back two or three tiers.
i) Do not keep dead storage. The principle of first-in first-out should be followed in
removing bags.
j) Do not stack bags on the ground for temporary storage at work site. Pile them
on a raised, dry platform and cover with tarpaulin or polythene sheet.
Coarse Aggregate Coarse aggregate for the works should be river gravel or crushed stone .It should be hard,
strong, dense, durable, clean, and free from clay or loamy admixtures or quarry refuse or
vegetable matter. The pieces of aggregates should be cubical, or rounded shaped and
should have granular or crystalline or smooth (but not glossy) non-powdery surfaces.
Aggregates should be properly screened and if necessary washed clean before use. Coarse aggregates containing flat, elongated or flaky pieces or mica should be rejected.
The grading of coarse aggregates should be as per specifications of IS-383. After 24-hrs immersion in water, a previously dried sample of the coarse aggregate should
not gain in weight more than 5%.Aggregates should be stored in such a way as to prevent
segregation of sizes and avoid contamination with fines. Depending upon the coarse aggregate color, there quality can be determined as:
a) Black aggregate is considered to have very good quality
b) Blue aggregate is considered to have good quality.
c) Whitish is considered to have bad quality.
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Fine Aggregate Aggregate which is passed through 4.75 IS Sieve is termed as fine aggregate. Fine
aggregate is added to concrete to assist workability and to bring uniformity in mixture.
Usually, the natural river sand is used as fine aggregate. Important thing to be considered
is that fine aggregates should be free from coagulated lumps.
Grading of natural sand or crushed stone i.e. fine aggregates shall be such that not more
than 5 percent
shall exceed 5 mm in size, not more than 10% shall IS sieve No. 150 not less than 45%
or more than 85%
shall pass IS sieve No. 1.18 mm and not less than 25% or more than 60% shall pass IS
sieve No. 600 micron.
River sand, crushed sand, 20mm msa and 10mm msa aggregate was used for different
purposes.
5. REINFORCEMENT Steel reinforcements are used, generally, in the form of bars of circular cross section in
concrete structure. They are like a skeleton in human body. Plain concrete without steel
or any other reinforcement is strong in compression but weak in tension. Steel is one of
the best forms of reinforcements, to take care of those stresses and to strengthen concrete
to bear all kinds of loads.
Mild steel bars conforming to IS: 432 (Part I) and Cold-worked steel high strength
deformed bars conforming to IS: 1786 (grade Fe 415 and grade Fe 500, where 415 and
500 indicate yield stresses 415 N/mm2 and 500 N/mm2 respectively) are commonly used.
Grade Fe 500 is being used most commonly nowadays. This has limited the use of plain
mild steel bars because of higher yield stress and bond strength resulting in saving of steel
quantity. Some companies have brought thermo mechanically treated (TMT) and
corrosion resistant steel (CRS) bars with added features.
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Bars range in diameter from 6 to 50 mm. Cold-worked steel high strength deformed bars
start from 8 mm diameter. For general house constructions, bars of diameter 6 to 20 mm
are used
Transverse reinforcements are very important. They not only take care of structural
requirements but also help main reinforcements to remain in desired position. They play
a very significant role while abrupt changes or reversal of stresses like earthquake etc.
They should be closely spaced as per the drawing and properly tied to the
main/longitudinal reinforcement.
In this project, Fe 500 of different diameters was used at all the places.
TERMS USED IN REINFORCEMENT
a) BAR-BENDING-SCHEDULE:-Bar-bending-schedule is the schedule of
reinforcement bars prepared in advance before cutting and bending of rebars. This
schedule contains all details of size, shape and dimension of rebars to be cut.
b) LAP LENGTH:-Lap length is the length overlap of bars tied to extend the
reinforcement length. Lap length about 50 times the diameter of the bar is
considered safe. Laps of neighboring bar lengths should be staggered and should
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Figure 5: Reinforcement in pier Figure 6: Reinforcement in pile cap
not be provided at one level/line. At one cross section, a maximum of 50% bars should
be lapped. In case, required lap length is not available at junction because of space
and other constraints, bars can be joined with couplers or welded (with correct choice
of method of welding).
c) ANCHORAGE LENGTH:-This is the additional length of steel of one structure
required to be inserted in other at the junction. For example, main bars of beam in
column at beam column junction, column bars in footing etc. The length
requirement is similar to the lap length mentioned in previous question or as per
the design instructions
d) COVER BLOCKS:-Cover blocks are placed to prevent the steel rods from touching
the shuttering plates and thereby providing a minimum cover and fix the
reinforcements as per the design drawings. Sometimes it is commonly seen that
the cover gets misplaced during the concreting activity. To prevent this, tying of
cover with steel bars using thin steel wires called binding wires (projected from
cover surface and placed during making or casting of cover blocks) is
recommended. Covers should be made of cement sand mortar (1:3). Ideally, cover
should have strength similar to the surrounding concrete, with the least perimeter
so that chances of water to penetrate through periphery will be minimized.
Provision of minimum covers as per the Indian standards for durability of the whole
structure should be ensured.
Shape of the cover blocks could be cubical or cylindrical. However, cover indicates
thickness of the cover block. Normally, cubical cover blocks are used. As a thumb
rule, minimum cover of 2”in footings, 1.5”in columns and 1”for other structures may
be ensured.
Figure 7: Cover blocks
6. Shuttering and Scaffolding
The term ‘SHUTTERING’ or ‘FORMWORK’ includes all forms, moulds, sheeting,
shuttering planks, walrus, poles, posts, standards, leizers, V-Heads, struts, and structure,
ties, prights, walling steel rods, bolts, wedges, and all other temporary supports to the
concrete during the process of sheeting.
Forms or moulds or shutters are the receptacles in which concrete is placed, so that it will
have the desired shape or outline when hardened. Once the concrete develops adequate
strength, the forms are removed. Forms are generally made of the materials like timber,
plywood, steel, etc.
Generally camber is provided in the formwork for horizontal members to counteract the
effect of deflection caused due to the weight of reinforcement and concrete placed over
that. A proper lubrication of shuttering plates is also done before the placement of
reinforcement. The oil film sandwiched between concrete and formwork surface not only
helps in easy removal of shuttering but also prevents loss of moisture from the concrete
through absorption and evaporation.
The steel form work was designed and constructed to the shapes, lines and dimensions
shown on the drawings. All forms were sufficiently water tight to prevent leakage of mortar.
Forms were so constructed as to be removable in sections. One side of the column forms
were left open and the open side filled in board by board successively as the concrete is
placed and compacted except when vibrators are used. A key was made at the end of
each casting in concrete columns of appropriate size to give proper bondings to columns
and walls as per relevant IS.
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Figure 7 Formwork of pier and false wall
7. CLEANING AND TREATMENT OF FORMS
All rubbish, particularly chippings, shavings and saw dust, was removed from the interior
of the forms (steel) before the concrete is placed. The form work in contact with the
concrete was cleaned and thoroughly wetted or treated with an approved composition to
prevent adhesion between form work and concrete. Care was taken that such approved
composition is kept out of contact with the reinforcement.
Design The form-work should be designed and constructed such that the concrete can be
properly placed and thoroughly compacted to obtain the required shape, position, and
levels subject
Erection of Formwork
The following applies to all formwork:
a) Care should be taken that all formwork is set to plumb and true to line and level.
b) When reinforcement passes through the formwork care should be taken to ensure
close fitting joints against the steel bars so as to avoid loss of fines during the
compaction of concrete.
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c) If formwork is held together by bolts or wires, these should be so fixed that no iron is
exposed on surface against which concrete is to be laid.
d) Provision is made in the shuttering for beams, columns and walls for a port hole of
convenient size so that all extraneous materials that may be collected could be
removed just prior to concreting.
e) Formwork is so arranged as to permit removal of forms without jarring the concrete.
Wedges, clamps, and bolts should be used where practicable instead of nails.
f) Surfaces of forms in contact with concrete are oiled with a mould oil of approved
quality. The use of oil, which darkens the surface of the concrete, is not allowed. Oiling
is done before reinforcement is placed and care taken that no oil comes in contact
with the reinforcement while it is placed in position. The formwork is kept thoroughly
wet during concreting and the whole time that it is left in place.
Immediately before concreting is commenced, the formwork is carefully examined to
ensure the following:
a) Removal of all dirt, shavings, sawdust and other refuse by brushing and washing.
b) The tightness of joint between panels of sheathing and between these and any
hardened core.
c) The correct location of tie bars bracing and spacers, and especially connections
of bracing.
d) That all wedges are secured and firm in position.
e) That provision is made for traffic on formwork not to bear directly on reinforcement
steel.
Verticality of the Structure All the outer columns of the frame were checked for plumb by plumb-bob as the work
proceeds to upper floors. Internal columns were checked by taking measurements from
outer row of columns for their exact position. Jack were used to lift the supporting rods
called props
STRIPPING TIME OR REMOVAL OF FORM WORK
Forms were not struck until the concrete has attained a strength at least twice the stress
to which the concrete may be subjected at the time of removal of form work. The strength
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referred is that of concrete using the same cement and aggregates with the same
proportions and cured under conditions of temperature and moisture similar to those
existing on the work. Where so required, form work was left longer in normal
circumstances
Form work was removed in such a manner as would not cause any shock or vibration that
would damage the concrete. Before removal of props, concrete surface was exposed to
ascertain that the concrete has sufficiently hardened. Where the shape of element is such
that form work has re-entrant angles, the form work was removed as soon as possible
after the concrete has set, to avoid shrinkage cracking occurring due to the restraint
imposed.
Concrete Production Concrete production is the process of mixing together the various ingredients—water,
aggregate, cement, and any additives—to produce concrete. Concrete production is time-
sensitive. Once the ingredients are mixed, workers must put the concrete in place before
it hardens.
For the project various grades of concrete was produced varying from M25 to M50.
a) Batching: The process of measurement of the different materials for the making of
concrete is known as batching. Batching is usually done in two ways: volume batching
and weight batching. In case of volume
b) batching the measurement is done in the form of volume whereas in the case of
weight batching it is done by the weight
c) Mixing: Mixing of concrete is a very important step for achieving good final
properties, and one of that can be quite difficult without the right equipment. This is
one of the best reasons for using ready mix concrete.
d) Compacting: When concrete is placed it can have air bubbles entrapped in it
which can lead to the reduction of the strength by 30%. In order to reduce the
air bubbles the process of compaction is performed. Compaction is generally
performed in two ways: by hand or by the use of vibrators.
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Figure 9: Curing of well foundation
e) Curing: Curing is the process in which the concrete is protected from loss of moisture
and kept within a reasonable temperature range. The result of this process is increased
strength and decreased permeability. Curing is also a key player in mitigating cracks
in the concrete, which severely impacts durability.
Properties of Concrete
Concrete has relatively high compressive strength, but much lower tensile strength. For
this reason it is usually reinforced with materials that are strong in tension
The elasticity of concrete is relatively constant at low stress levels but starts decreasing
at higher stress levels as matrix cracking develop. Concrete has a very low coefficient of
thermal expansion and shrinks as it matures. All concrete structures crack to some
extent, due to shrinkage and tension. Concrete that is subjected to long-duration forces
is prone to creep.
Curing of Concrete
Curing concrete is the term used for stopping freshly poured concrete from drying out too
quickly. This is done because concrete, if left to dry out of its own accord, will not develop
the full bond between all of its ingredients. It will be weaker and tend to crack more. The
surface won't be as hard as it could be. Curing can be performed in different ways:-
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8. BATCHING PLANT
The Signature Bridge Site at Wazirabad had a batching plant of capacity 60m3/hr. The
batching plant had various execution modes for feeding of the aggregates like star batcher,
compartment batcher and in-line silo execution. The four aggregate gates are
pneumatically operated and the weighing is done through electronic load cells. The
aggregates are weighed in a skip bucket and then are moved up to the turbo pan mixer
by two units of pole change motors. These pole change motors operate the skip at two
different speeds to reduce the time cycle at each batch and at the same time protect the
important components of
the weighing system. The batching of water and admixture is by weight. The cement from
the cement silos is fed into the combined cement water weigher through screw conveyors.
The water and cement are weighed in a combined weigher and discharged into the pan
mixer. The Turbo pan mixer is designed to handle various slumps of concrete and to
achieve a homogenous mix in the shortest possible time.
The plant can deliver the 60 m3 per hour output as each and every operation of the plant
has been sequenced to achieve this output. The 60M batching plant is fully computerized
and offers features like material in air compensation. The batching plant can also be fitted
with electronic moisture meter and an interface in the control system provides the Batch
reports through the printer. The interface also facilitates the transfer of all data from the
control system to a computer where the data can be processed as per the customer
requirements. The batching mixer mixes the following-
a. Cement
b. Sand
c. Aggregate
d. Admixture
e. Fly ash
f. Water
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Figure 11: material hopper
Figure 10: Batching plant
Cement is loaded through a pump in which cement was inserted manually. The main
mixture had six blades for mixing and a hydraulically controlled gate for ejecting the mix.
In a nearby tank water is stored and added via a pipe. Admixture- Naphthalene
Formaldehyde is added to-
Increase the setting time Reduce the water/cement ratio
Sand and aggregate are loaded on a large conveyor belt, whose quantity is electronically
controlled. For each batch production these are transferred through electronic commands.
The batching plant also has an exit for dry concrete that gets blown in the process. These
dry particles are returned to the batching mixture using a compressor. It takes around 20-
30 seconds to mix and rest 30 seconds are used in bringing water,
aggregate and sand. The uniqueness of the batching plant is its ability to achieve the rated
output with minimum break downs. Hence, it is an ideal plant for use in RMC operations
and for projects where the down time of the plant is expensive.
9. FOUNDATIONS
Two types of foundations used for the project are:
1. Well foundation.
2. Open foundation/Pile foundation.
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Figure 12: Schematic diagram of well foundation
Well foundation Well foundations are the most common types of deep foundations used for bridges in
India.
Components of well foundation
a) Well Cap - The well cap is a RCC slab of sufficient strength to transmit the forces from
pier to the body of well. It is generally kept at low water level. The dimension of the
well cap should be sufficient to accommodate the pier. The recommended minimum
thickness is 0.75 m.
b) Steining –It is the wall of well & is built over a wedge shaped portion called well curb.
The steining is designed such that it can be sunk under it’s own weight. The thickness
should be sufficient so as to overcome skin friction developed during sinking by its
own weight.
c) Well Curb –The well curb supports the steining. The curb should be slightly projected
from the steining to reduce the skin friction during sinking of well. It is made of RCC
with steel cutting edge.
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d) Cutting Edge –The cutting edge is either projected below the curb as a sharp edge or
can also have flat bottom. The projected edge is likely to be damaged in strata of
gravels and boulders. In such soils the flat bottom cutting edge is provided.
e) Bottom Plug –The bottom plug is made bowled shape in order to have an arch action.
The bottom plug transmits load to soil below. When sunk to its final depth bottom part
is concreted to seal the bottom completely. The thickness varies from ½ to full inside
diameter of the well so as to be able to resist uplift forces. The concreting should be
done in one continuous operation. When wells contain more than one dredge hole all
should be plugged to the same height. If the well is to rest on rock, it should be
anchored properly by taking it 25 cm to 30 cm deep into rock The bottom plug should
be of rich concrete (1:2:4) with extra 10 % of cement. f) Sand Filling - After concreting the bottom plug the sand is filled above the bottom plug
and below top plug. Sand filling provide stability of well, reduce tensile stress
produced by bending moment and distributes the load of super structure on to the
bottom plug. Sand filling relieves load to steining to some extent. g) Top Plug –This is a plug at the top of the well below the well cap. This helps
transferring the load through the granular material into the staining
Sinking of Well Foundation a) Laying of Curbs - In dry ground excavate up to 50 cm in river bed and place the cutting
edge at the required position. If the curb is to be laid under water and depth of water
is greater than 5 m, prepare Sand Island and lay the curb. If depth of water exceeds
5 m built curb in dry ground and float it to the site. b) Construction of Well Steining –the idea is to initially sink the well under its own weight.
The steining should be built in short height of 1.5 m initially and 3 m after a 6 m grip
length is achieved. The verticality should be maintained. The aim of the well sinking
is to sink the well vertically and at the correct position. c) Jackdown sinking: It is basically transferring the forces exerted by the hydraulic jacks
on the earth anchors to the heavy duty pressurization girders resting on the steining
top through stools. The earth anchor pairs are placed such that two girders systems,
both crossing the well sides, can be positioned, with hydraulic jacks at the ends of the
girder, located such that they are directly above the Centre of the earth anchor pair.
18
Figure 13: Jackdown of well foundation
Figure 14: Grippers rod anchored into ground
Following procedure is followed for the jack down of the well foundation:
a. Girder fitted with bottom pieces of gripper rod assembly is placed on the earth
anchors and are fixed by grouting after gripper rod is at 75 m depth.
Supporting stools are then placed on the steining to suit the location of the anchors.
b. Pressurization girders are then erected over the stools and pressure plates fixed on
top of the girders at ends.
c. 250 MT capacity hydraulic jacks along with upper gripper attachments are erected and
the gripper rods are fixed by locking the upper gripper attachment.
d. 1000mm Pieces of Gripper rod is then fixed with the adjustment rods at required height
and held in position by locking the lower gripper assembly.
e. All jacks are aligned and leveled properly.
f. The pressure hoses are connected with power pack and jacks.
g. Loading is applied with power pack
19
Figure 8: Power pack Figure 15 Power pack
h. After lifting of ram by about 40 to 100mm wedges are placed on bearing plates on
either side of the anchor couplers.
i. The lower gripper assembly is locked and upper gripper assembly is released.
j. Ram is brought to its original position and upper gripper assembly is locked.
k. Lower gripper assembly is then unlocked.
l. The above operations are supported by air/water jetting till sinking is achieved.
LOAD APPLICATION
a) Each Jack has Separate Control valve on the power pack for application of
pressure. The adjustment wherever required will be maneuvered by closing or releasing
the control valve.
b) The jacks placed on upper side of the tilted well shall be given with additional load than
that of the lower side.
c) Releasing of pressure on any one jack shall be done with proper care. In case of tilting of
the girder on any side due to releasing of pressure, then releasing shall be done on both
the jacks placed on the said girder
d) To cater for additional safety precautions against lifting of girder in case of any failure of
grips or larger uneven loading the girders shall be arrested to additional rebar placed in
the steining.
e) 25 mm dia. Bar shall be placed in the steining during concreting on each
supporting stool.
20
Figure 16: Formation of Slumps inside the well
SINKING PROCEDURE
In sandy clay strata first sump condition shall be made to the extent of 1.5 to 2 meters
and then loading shall commence with initial 50 MT per Jack and gradually in increments
of 25 MT till well starts sinking. The intensity of loading shall be kept constant till
appreciable sinking is achieved and well is not further going down. Thereafter sump /
hump will be checked and loading shall be released in case of hump / or less sump to
resume grabbing once more.
a. In sandy strata each jack shall be loaded to 100 MT and then grabbing operation is started.
The loading shall be kept at 100 MT till sinking of well starts. After appreciable sinking is
over and with the above loading the sump of the well is checked, and grabbing with the
above loading is continued.
Measures for rectification of tilts and shifts The primary objective while sinking the well is to sink it straight and at a correct position,
however it is not an easy task to achieve this objective. During the sinking the well may tilt
to one side or it may shift away from the desired position. The following precautions are
to be taken as far as possible:
a) Outer surface should be regular and smooth.
b) Radius of the curb should be 2 to 4 cm larger than the radius of the steining.
21
c) Cutting edge should be of uniform thickness and sharpness.
d) Dredging should be done uniformly on all sides. According to IS: 3955-1967 the tilt should generally be limited to 1 in 60, and the shift to
one percent of the depth sunk. In case the tilt and shifts exceeds the above limits the
following measures are taken for their rectification.
i. Eccentric loading: Construct eccentric welded framed bracket and load the
platform thus made with 400 to 600 tons load. This is shown in Fig. below.
Figure 17: Rectifying tilt by eccentric loading
iii. Water jetting: Jett are applied on the outer face of the high side of well, skin
friction is reduced and tilt is rectified.
iv. Excavation under cutting edge: Excavate under cutting edge by dewatering in
case dewatering is not possible divers are sent to loosen the strata.
v. Pulling the well: It is effective only in early stages of sinking. Well is pulled
towards the higher side using steel ropes around the well.
vi. Pushing the wells by jack: It can be done using a suitable arrangement or
hydraulic jacks by resting it against the vertically sunk well.
Figure19: well staining
vii. Changing the pressure in power packs: If the tilting occurs during the Jackdown
process it can be easily rectified by increasing the pressure on the higher jack, by
using the power pack.
Special type of well foundation being used at the site
At Signature Bridge site normally wells used are of 7m inner and 9 m outer diameter with
rock strata at 36m depth but due to varying rock depth and special structural requirement
a special type of well was required to be constructed at one of the locations. At P23
location, where the back stay cables were supposed to be anchored the well foundation
was not only supposed to bear the compressive forces but also were required to overcome
the tensile forces to support the weight of the central pylon.
To overcome this problem the wells were designed with 10.5m inner diameter and 17.5m
outer diameter with depth of well going to 25m, the well steining was designed such that
there were
hollow casings left in the well steining placed at an angle of 22.5⊆at their centre in which
Piles can be driven later on after the sinking of the well. These piles will be driven 6m
inside the rock a stratum over which well is resting. The structure of the well will take the
compressive forces and the piles will cancel the effect of tensile forces that will be
generated by the back stay cables.
23
10. Open foundation/Pile foundation Depending upon the type of soil, foundation piles are used in following ways:
a. Bearing piles
b. Friction piles
c. Friction cum bearing piles
The bearing piles are designed as those which transmit the load to foundation strata
directly without taking in to account the frictional resistance offered by enclosing soil. The
passive earth pressure resistance is taken in to account only for the purpose of
determining its resistance against the horizontal force. Such bearing piles are generally
taken up to or in to the hard strata, soft or hard rock, hard consolidated sandy or gravelly
soil.
Friction piles are those in which the load is transmitted by the pile through friction offered
by surrounding soil. Such piles can be provided in cohesive soils not subjected to heavy
scour. Friction cum bearing piles designed in such a way that the load is transmitted both
by friction of the surrounding soil and the bearing resistance of the founding soil at the tip
of pile.
Pile Classification by Construction Method a) Precast Driven Piles –These are usually of RCC or pre-stressed concrete and
generally small in size for ease in handling. The main advantage of this type of pile is
that its quality, in terms of dimension, use of reinforcement and concrete, can be
ensured as the piles are cast in a yard under controlled conditions. However care is
needed while handling, transporting and driving the pile to avoid damages. More to it,
the limitation of length depending upon the capacity of the driving equipment is a
disadvantage as these cannot be taken very deep except by joining. Generally, the
depth over which these are used is restricted to 36 m.
b) Driven Cast-in-Situ Piles- A steel casing pile with a shoe at the bottom is driven first
to the required depth. The reinforcement cage for the pile is then lowered inside the
casing and the pile is concreted. As the concreting of the pile proceeds upwards, the
casing is withdrawn keeping a suitable overlapping length. When such piles are driven
in soft soil and the tube is withdrawn while concreting, it affects resistance and
changes the property of the soil and this also affects the capacity of individual piles.
These are not suitable for use in soft soils, in greater depths or where keying with the
rock is required. 24
c) Bored cast-in-situ piles –In the bored cast-in-situ process, a larger diameter casing is
used. A casing of 3 to 4 m in length is provided on top of the bore hole which is driven
with the help of a bailor. Boring further below this casing is carried out by chiselling
and the side walls are kept stable by circulating bentonite slurry inside the bore hole.
The boring is continued up to the layer decided for founding the structure. After
reaching the desired founding level, the chisel is removed, bore-hole flushed,
reinforcement cage lowered into the hole, and held in position by tack welding it to
the support bars at the top of the casing. After this, concreting is carried out by using
tremie, keeping its end always below the top level of rising concrete. The concreting
is continued till a good quality concrete is seen at the top of the bore hole. After this,
the tremie is removed and when the concrete has reached the top, the casing pipe
on the top is also removed. The bentonite mix should be periodically checked for its
specific gravity and changed as, due to constant use, it can get mixed with the soil
and deteriorate in quality. This type of pile can be used even where the pile is keyed
into the rock as chiselling in the rock can be carried out more easily. These piles serve
as bearing-cum-friction piles. The diameters of such piles are generally more than
1.0m and can go up to 3.6m or more. They can be used singly or in group and are
good replacements for well foundations required for bridge piers in rivers with clayey
and mixed soils. These kind of piles are used being used for piers at western
approach. d) Bored pre-cast piles –In this, as the name itself suggests, a hole is bored using a
casing and a pre-cast pile is inserted into it. After securing it in position, the casing is
withdrawn. A particular process used for bored pre-cast piles is the Benoto process
which involves a steel tube being pushed into the soil, turned and reversed using
compressed air. The tube is in the form of a casing and is driven for the entire depth
after the soil is progressively grabbed from the tube. The process is continued till the
tube reaches the pre-determined level. Then the pre-cast pile is lowered inside and
held in position. The tube is lifted gradually after filling the annular gap between the
pre-cast pile and the soil by grouting. e) Driven steel piles –Steel piles can be circular or in other structural shapes. The
circular ones are made in the form of either welded or seamless piles. Usually steel
25
or cast iron piles used earlier for bridge structures are of longer diameter and screw
type. These were used in past when loading was less. These piles are suitable for
being driven through cohesive soil to reach up to the hard strata and to serve as
bearing piles. They are not suitable where heavy scour is expected and for foundation
for bridges when foundations are situated wide apart.
f) Driven timber piles –Timber piles have been extensively used in America. These have
been used in India on the railways and highways, for temporary bridges. Timber piles
are of hard wood, and used in natural form with thin end cut or suitably sized. They
are used mostly as end-bearing piles in clusters. They are normally used in lengths
of 12m and extended by splicing for use in deeper channels. The piles protruding
above bed/low water level are suitably braced in cluster.
Cast Insitu Piles During drilling of cast insitu piles at Signature Bridge, Wazirabad bentonite was used as
the drilling fluid. Bentonite is used in drilling fluids to lubricate and cool the cutting tools, to
remove cuttings, and to help prevent blowouts. Relatively small quantities of bentonite
suspended in water form a viscous, shear thinning material. At high enough concentrations
(~60 grams of bentonite per liter of suspension), bentonite suspensions begin to take on
the characteristics of a gel (a fluid with a minimum yield strength required to make it
move).for the above reasons it is widely used in construction industry for drilling purposes.
Measures to be taken while boring for cast insitu piles are:
a) During the boring, samples should be taken and sent to the lab for testing or in-situ
tests should be carried out.
b) Dimension of the pile should not be less than that specified. When an enlarged base
is provided, it should be concentric with the pile with a tolerance of 10%.Slope of the
frustum should not be less than 55o. c) If bentonite is used, it should be maintained a minimum of 1.5m above the water table
d) Adequate temporary casing can be provided for ensuring stability near the ground. It
should be backfilled if rapid loss of drilling fluid occurs. The temporary casing should
be free from projections and distortion during concreting.
e) After concreting of the pile, the empty bore hole should be backfilled.
26
Figure 20: Pile Driving
Measures to be taken for reinforcement of a pile
a) Should be pre-assembled and wired into position b) Minimum clear cover of 40mm should be provided and should be increased if the
concrete is in contact with the earth.
c) Joints should be avoided and shall be provided if the full length is not possible. When
joints are provided, appropriate lap length shall be provided to satisfy the
development length criteria.
Measures to be taken during concreting for cast insitu piles:
a) The workability of the concrete should be such that a continuous monolith shaft of full
cross-section is formed. No contamination of concrete is allowed.
b) It should be ensured that mix and placing of concrete does not result in arching. c) Concrete under water or drilling fluid should be poured through tremmie as per IS
2911.Hopper and pile of the tremmie should be clean and watertight.
d) At all times, tremmie should penetrate the previously prepared concrete so as to
prevent contact with the drilling fluid. Sufficient quantity of concrete should be
maintained in the pipe so that pressure exceeds that of the fluid.
e) Internal diameter of the pipe should not be less than 200mm for concrete with max.
size of aggregate 20mm.
27
Measures to be taken while Extracting Temporary Casing: a) Should be lifted while the concrete is sufficiently workable to avoid disturbance or
lifting. b) Concrete should be placed continuously as casing is extracted. c) Pile should be formed at least 30cm above the cut-off level.
Pilling Steps Bored cast in situ piles are constructed in the following sequence
1) Survey: The surveyor set out the center of the bored pile location.
2) Utility diversion: A circular pit of diameter 1700mm and depth 1500 mm shall be
manually excavated at the location to ensure that the utilities are present.
3) Checks for Pile vertically and position: During the process of boring following checks
should be made:
a) Check the verticality of the casing during installation by plumbing from two
perpendicular directions.
b) Check of the eccentricity of the borehole after installation of casing. If the
eccentricity is more than 50mm then reinstallation is done.
c) The verticality of the casing is checked continuously until the toe is reached and
is kept within a tolerance of 50mm.
d) Variation in dimension is limited to +50mm and - 10mm.
e) Variation of level at the top should not be beyond +25mm. 4) Boring of soil-Boring is carried out with the help of a rig up to the required depth. The
verticality of the hole to be bored is kept on monitored and later checked before the
lowering of the reinforcement cage.
5) Installation of temporary casing to stabilize the upper bore, a temporary steel casing
of length 2.5- 3m is installed:
a) A 1000mm diameter hole is drilled using hydraulic boring machine up to a depth of 3-4m.
b) The casing should then be lowered in the hole with the help of a crane.
c) The casing is then driven in to the ground with the help of a rotatory machine
until about 300mm is left above the ground. The rig is then used to progress the
28
d) excavation to the bottom of the casing pipe and then suitable polymer system is
added before further excavation.
e) Bentonite should be added continuously during excavation. And the depth is
measured with the help of the sounding tape.
6) Cleaning of base:
a) Boring is stopped when the toe of the pile level is reached. The borehole is
cleaned carefully and the soil is removed.
b) The depth is checked before the lowering of the cage. 7) Fabrication and installation of reinforcement cage: a) Cutting and bending of bars shall be carried out with approved schedule in fabrication
yard or on the site. Tie wires shall be used for binding the bars. Circular concrete
spacers shall be provided of the same grade of the pile. Vertical distance between
each layer of spacers shall be 4m. The reinforcement cages shall be lowered in the
borehole using steel slings and shackles. Cages shall be spliced on the fabrication
bed and lowered in the trench.
8) Concrete with slump in the range 175+25mm shall be supplied from batching plant.
All concrete delivered shall be visually inspected and checked against delivery note
before being tested and used. Before a pouring is started two delivery trucks should
be available at site.
9) Concrete shall be placed using pipes. 10) Pipes are joined towards into the hole. The end of the pipe should not be more than
300 mm above the bottom of the pile to ensure that free fall of concrete shall not be
more than 1.5m.
11) The concrete shall be discharged from the delivery truck to a hopper connected to
the pipes. As the level of the concrete in the borehole rises, the s shall be withdrawn
accordingly to aid the flow of concrete. Section of the pipe shall be dismantled from
the top as the pipe is withdrawn.
12) During concreting, the level of concrete inside the borehole shall be monitored
either with a weighted tape or chain. Encasing shall be withdrawn after initial setting
of concrete.
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Figure 21: HSFG 8.8 grade bolt
Figure 22: Placement of steel girders
11. PLACING OF GIRDERS
The portion of the Signature Bridge between P3 and P19 is cable stayed and will not be
loaded on any piers. To support the load of the slabs temporary structures are being
placed on the river bed which will be removed once the precast slabs are stressed to hold
their own load.
During the entire stretch of the bridge 114 main girders will be placed along with 12 cross
girders which will be placed at the distance of 4.5m each. Before these girders are bolted
to the structures they are rested on temporary structures to have a safe working
environment for the labour.
Girders were made out of S355 grade steel bolts were HSFG 10.9 under the pylon and
HSFG 8.8 at all other places. Full strength fully penetrated welds were made during the
preparation of girders. All the girders were mad in a yard in CHINA and were transported
to site via sea and land
. Following procedure was followed while placing the girders at P19 for Insitu slab casting:
30
12. QUALITY ASSURANCE/ QUALITY CONTROL Quality Assurance (QA) refers to the planned and systematic activities implemented in a
quality system so that quality requirements for a product or service will be fulfilled. It is the
systematic measurement, comparison with a standard, monitoring of processes and an
associated feedback loop that confers error prevention. This can be contrasted with
Quality "Control", which is focused on process outputs.
Two principles included in QA are: "Fit for purpose", the product should be suitable for the
intended purpose; and "Right first time", mistakes should be eliminated. QA includes
management of the quality of raw materials, assemblies, products and components,
services related to production, and management, production and inspection processes.
Suitable Quality is determined by product users, clients or customers, not by society in
general. It is not related to cost and adjectives or descriptors such "High" and "Poor" are
not applicable. For example, a low priced product may be viewed as having high quality
because it is disposable where another may be viewed as having poor quality because it
is not disposable.
Quality assurance in construction can be defined simply as making sure the quality of
construction is what it should be. Process Technical Resources has qualified and
experienced personnel that can plan and perform the systematic steps necessary for a
program of quality assurance in construction.
Quality assurance in construction involves all those planned and systematic actions
necessary to provide confidence that the facility will perform satisfactorily in service.
Quality assurance in construction addresses the overall problem of obtaining the quality
of the facility to be built in the most efficient, economical, and satisfactory manner possible.
Within this broad context, quality assurance involves continued evaluation of the activities
of planning, design, development of plans and specifications, advertising and awarding of
contracts, construction, and maintenance, and the interactions of these activities. In its
broadest form quality assurance includes quality control as one of its elements. Quality
control is the responsibility of the contractor, while quality assurance also includes
acceptance. Acceptance involves sampling, testing, and the assessment of test results to
determine whether or not the quality of construction is acceptable in terms of the
specifications. 31
Construction planning is a complex process that must be kept current with the actual
construction taking place in the field. The construction plans, just in terms of day-to-day
changes, must be kept up-to-date. However, in the ebb and flow of events during
construction there are usually a number of schedule changes that arise as a result of
unforeseen ents. Failure to keep the construction planning dynamic and up-to-date
can create confusion and delays.
Not only must the plans keep pace with the daily events communication of the changes in
the co nstruction plans must be disseminated quickly to the affected personnel.
Quality assurance in construction requires that the procedures for incorporating design
changes into the construction plans be well developed and fully utilized. The earlier that
design changes are recognized and implemented the lower the cost. Quality assurance
efforts in construction must closely monitor how well management of the design, and
change of design processes are functioning. These represent the quality issues that need
to be monitored during the quality assurance effort and acceptance testing. Another area of activity for quality assurance in construction that must be continuously
monitored is the development of plans and specifications. Architectural and engineering
plans and specifications often change during the construction phase of a complex project.
It is important that the procedures for incorporating these changes into the construction
plans be well developed and consistently followed.
In order to minimize construction cost while meeting all of the specifications in the plans
and design requires that the advertising for bids and awarding of contracts be closely
monitored. The qualifications of the contractors and subcontractors to perform the services
advertised and meet the quality requirements should be examined carefully all during the
construction phase of the project. This is an element in the program for quality assurance
in construction. Finally, the construction activities should be closely monitored to ensure
that the engineering plans and specifications are being met or exceeded throughout the
construction process.Process Technical Resources has experienced quality assurance
personnel that can develop a quality assurance in construction program that meets the
needs and requirements of the project owner Quality control, or QC for short, is a process
by which entities review the quality of all factors involved in production.
32
Elements such as controls, job management, defined and well managed processes,
performance and integrity criteria, and identification of records
1. Competence, such as knowledge, skills, experience, and qualifications
3. Soft elements, such as personnel integrity, confidence, organizational culture,
motivation, team spirit, and quality relationships.
Controls include product inspection, where every product is examined visually, and often
using a stereo microscope for fine detail before the product is sold into the external
market. Inspectors will be provided with lists and descriptions of unacceptable product
defects such as cracks or surface blemishes for example.
The quality of the outputs is at risk if any of these three aspects is deficient in any way.
Quality control emphasizes testing of products to uncover defects and reporting to
management who make the decision to allow or deny product release, whereas quality
assurance attempts to improve and stabilize production (and associated processes) to
avoid, or at least minimize, issues which led to the defect(s) in the first place. For contract
work, particularly work awarded by government agencies, quality control issues are
among the top reasons for not renewing a contract.
Quality control during the construction process is extremely important in order to
safeguard the value of the owner's investment. Process Technical Services QAQC
personnel can perform checks and tests throughout the construction process, providing
the project owner assurance that the project is being built according to specifications.
The first step in establishing the requirement for construction QAQC is to develop an
overview of the entire quality program. A quality management plan is essential and the
form of the construction organization needs to be established.
The responsibilities and authorities of the various principals in the construction QA/QC
organization need to be established. These include the Environmental Protection Agency
(EPA), the project owner, the engineer of record, the construction manager, and the
construction contractors. Included in this assignment of responsibilities are the
Construction Manager’s quality assurance personnel and the contractor’s quality control
personnel.
33
maintain all submittal files via a combination of a secure document filing and storage
system, and a computerized document tracking system.
General construction inspection and verification requirements include inspections, QC
testing, QA testing, establishing construction acceptance criteria, construction audits,
compliance with handling, storage, packaging, preservation, and delivery requirements,
and material identification and traceability.
Inspections will uncover construction deficiencies. These will need to be identified,
reported and corrective and preventive action taken.
Document handling and retention procedures are important. Records must be updated
on a daily basis and a daily construction report issued. The construction QAQC plan
requires that all construction drawings be stored and that As-Built drawings be prepared
and reviewed.
For any construction activity the Environmental Protection Agency requires submittals
that conform to regulation and must be approved by the EPA prior to construction.
Field changes for QAQC will be limited to the construction QAQC plan and contractor
quality control plan changes. Changes to construction processes or design plans and
specifications are governed by the remedial action work plan and design change order
procedures.
The project owner, the construction manager, site manager, or construction quality
assurance officer may initiate revisions to this construction QAQC plan. It may be revised
whenever it becomes apparent that the construction QAQC procedures or controls are
inadequate to support work being produced in conformance with the specified quality
requirements, or are deemed to be more excessive than required to support work being
produced in conformance with the specified quality requirements.
Construction of a process plant is complex undertaking. However, the project owner is well
advised to invest in QAQC services in order to prevent poor quality construction that may
result in serious project delays and substantial cost over-runs. Process Technical Services
has experienced and qualified personnel that are familiar with construction QAQC
procedures and are available to establish a construction program for your project, or to
provide support for an established construction QAQC project team.
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13. TESTS CONDUCTED
Test conducted on various materials Various tests are conducted on materials which are used at site as well as for production
of concrete at the Batching Plant. These includes test on cement, fine aggregate, coarse
aggregate, water, bricks, TMT bars etc. Some of these test can be conducted on site where as others are required to be performed
in a lab. The various tests being conducted at The Signature Bridge, Wazirabad site are:
a) Sieve analysis of all the aggregate.
b) Silt Content.
c) Moisture content.
d) Flakiness and elongation.
e) Impact Value test.
f) Abrasion value test.
g) Crushing Value test.
h) 10% fine test.
i) Water pH level, cl level & SO3 content.
j) Cement physical test.
k) Specific gravity & density test.
l) Water testing.
m) TMT bars rusting inspection
35
Test Conducted on Fresh Concrete
Tests for workability:
Concrete is said to be workable when it is easily placed and compacted homogeneously i.e.
without bleeding or Segregation. Unworkable concrete needs more work or effort to be
compacted in place, also honeycombs &/or pockets may also be visible in finished concrete.
Various tests for workability are:
1. Slump test
2. Compaction Factor test. The most commonly used workability test in the field the slump test is
described below.
SLUMP TEST
Apparatus required for Slump Test:
a) Slump mould with bottom diameter 20 cm, Top diameter 10 cm and Height 30 cm.
b) Base plate for fixing the mould.
c) Tamping rod 16mm dia 600 mm long.
36
Figure 23: Test and their Frequency
d) Steel scale. 2) Test procedure:
a) Sampling:
1) From Mixers: At least three approximately equal sample increments totalling to
0.02 m3 shall be taken from a batch during concrete discharge and each sample
increment shall be collected by passing a clean shovel in to the stream of
concrete.
2) From concrete at the time and place of deposition: The sample shall be taken
while a batch of concrete is being, or immediately after it has been, discharge on
the site. The sample shall be collected from not less than five well-distributed
positions, avoiding the edge of the mass where segregation may occur.
The composite sample obtained by either methods described above, shall be mixed well
to ensure uniformity. The sample thus obtained shall be used for the test.
3) Testing
a) Clean the slump mould and fix it firmly with the base plate and keep in a level
ground.
b) Fill the slump cone with the collected concrete sample. Concrete to be filled in
four layers, each layer compacted with the tamping rod 25 blows.
c) While tamping the blows to be distributed uniformly over the cross section, and
the second and subsequent layer should penetrate into the underlying layer.
d) After filling the mould level the top with a trowel and clean the excess concrete
fallen over the base plate.
e) Gently lift the slump cone and allow the concrete to subside.
f) Measure the slump of concrete in millimeter.
Note: Some indication of cohesiveness and workability of the mix can be obtained, if after
the slump test has completed, the side of the concrete is tapped gently with the tamping
rod, a well-proportioned concrete
which has an appreciable slump will gradually slump further, but if the mix has been badly
proportioned, it is likely to fall apart Test Conducted on Hardened Concrete Cube Testing
is conducted on hardened concrete
37
Figure 24: Cube specimen Figure 25 Cube mould
1. Age of Test:
The test shall be conducted at recognized ages of the test specimens, the most usual
being 7 days and 28 days. Where it may be necessary to obtain the strength tests at
1 day and 3 days can also be made. The ages shall be calculated from the time of the
addition of water to the dry ingredients.
2. Number of specimens:
At least three specimens, preferably from different batches, shall be made for testing
at each selected age.
Note: When a full investigation is being carried out, it is advisable for three separate
batches to be made for each given variable. An equal number of specimens for each
variable should be made.
3. Procedure:
Specimens stored in water shall be tested immediately on removal from the water and
while they are still in wet condition. Surface water and grit shall be wiped off the
specimens and any projecting fins removed. Specimens when received dry shall be
kept in water for 24 hours before they are taken for testing. The dimension to the
nearest 0.2mm and the weight shall be noted before testing.
1. Placing the specimen in the testing machine. The bearing surface of the testing
machine shall be wiped clean and any loose sand or other material removed from
Figure 25: Compression testing machine
the surface of the specimen which are in contact with the bearing plates.
2. The cubes shall be placed inside the machine in such a way the load applied to
the cube in the opposite direction of the cube as cast.
3. Cubes shall be carefully aligned to the center of the bearing plates so that the
axial load is applied to the specimen.
4. No packing to be used between the specimen and the bearing plate. Adjust the
top plate so that it will have a flat seating on the specimen.
5. Apply load at the rate of 140 kg/cm2 (approximately 310 KN) per minute.
6. Apply load until failure of the specimen, (i.e. the specimen shall not sustain any
further loading) and note down the maximum load at which the specimen has
failed.
4. Calculations: The average of the three values of strength shall be taken as the representative strength
of the batch provided. The individual variation is not more than + 15 % form the average.
Maximum load at which the specimen failed
Strength of specimen = ------------------------------------------------------
kg/cm2 Area of the specimen
Figure 26: Silt content test
Silt content Test: There are two types of harmful substances preset in fine aggregates i.e. organic matter
produced by decay of vegetable matter and/or clay and silt,which form coating thus
preventing a good bond between cement and the aggregates. If present in large quantities,
result in the increase water-cement ratio and finally affecting the strength of concrete. Field
test is generally conducted in order to determine the volumetric percentage of silt in natural
sand for percentage up to 8%, otherwise more detailed test as prescribed by standard
code are required to be conducted.
14. CONCLUSION After having completed my training, I have gained some basic knowledge in the field of
bridge construction. This industry has familiarized me with the industry and its
requirements. I have been exposed to the standard requirement that needs to be followed
during designing during my internship period. Also, this internship has proved how crucial
it is to have a good understanding and proper communication between the site and office,
One of the primary objective of the project was to understand the economic factor and how
things are implemented. This internship has further opened the doors of research in this
field and also emphasized on the use of innovative and unconventional means to achieve
the desired objective. Basically, the whole thing can be summed up to the fact that- to
erect a structure that is satisfying the norms within the given limits, using the minimum
possible resources because if the economy of that particular structure is considered and
it is seen that all the resources have been over used, then it is a unnecessary waste of
public money. On the other hand if the resources are under used the structure will be
highly uneconomical but not safe. So, again the public interest is being violated and it is
not permissible at all.
For any country to progress it needs to have a proper infrastructure else no development
can proceed from the word go. So as a civil engineer we will have to be focused and
determined on the things at hand because if we fail in our duties the result will be
hazardous. An engineer learns with time and as he gathers experience. This was a
beginning and still there is a long way to go. There are many things learn from the books
and experience to gather from real life scenarios but all that I hope at this point of time is
that all these factors together mould me into a good civil engineer and more importantly a
better human being.
Finally, I conclude that this project has met all its objectives and the results speak for
themselves. On this note I come to the end of my project.