1. INTRODUCTION

Artistic view of proposed bridge

India’sfirst “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 175 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.

Bridge Details

Description Of Project

Ø Period of Contract: 20/3/2013 to 19/12/2016

Ø TOTAL LENGTH: 575m (8 lanes)

Ø PYLON HEIGHT: 151.14m (5400 ton) Ø FOUNDATIONS: 6open and 18 well foundations Ø ADDITIONAL WORK: eastern and western approaches

2. 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.

k. The need for low-voltage electric power supplies for temporary lighting, portable tools and equipment.

3. 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 (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’tthat should be followed -

a) Do not store bags in a building or a godown 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 properly and ensure that they

are kept shut.

d) Do not stack bags against the wall. Similarly, don’tpile 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 colour, 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.

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.

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 yieldstresses 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.

Tying of reinforcement of pier

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.

c) 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 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).

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.

Structural member Cover to reinforcement (mm)

Footings 40

Columns 40

Slabs 15

Beams 25

Retaining wall 25 for earth face

20 for other face

Cover Blocks

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.

Formwork for pier and falsewall

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.

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 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

batching the measurement is done in the form of volume whereas in the case of weight batching it is done by

the weight b) 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. Mixing distributes the aggregate evenly throughout the cement paste, ensures that all of the cement has been fully saturated in water, and removes large air voids. Under mixing leaves large flaws and thus results in inferior strength, while over mixing wastes time and energy and can destroy entrained air voids. The lower the workability the more mixing time and mixing energy is required. c) Transporting: Once the concrete mixture is created it must be transported to its final location. The concrete is placed on form works and should always be dropped on its final location as closely as possible. Workability: The workability that is required depends primarily on how the concrete is to be placed. Concrete can be poured, pumped, and even sprayed into place, and this will affect the workability that is needed. Other factors such as the shape of the moulds, the rebar spacing, and the equipment available at the site for consolidating the fresh concrete after it is placed must also be considered. Workability is usually defined by the slump, which is the

tendency for the fresh concrete tends to spread out under its own weight when placed onto

a flat surface

e) 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. f) 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 (often steel). 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:-

a) Leave the form work used to create the concrete formation: The form work itself, if left in place, or on the

underneath of a suspended slab, or around a concrete column will stop the concrete drying out too quickly, and

so can be said to be a curing agent.

b) Use ponding, it is done by forming a dam wall of sand around the concrete formation and then flooding with

water.

c) Spray water onto the formation. d) Use some sort of cover that holds and retains sprayed on water, like a sand layer. e) Use a plastic shield, which basically is a plastic sheet laid on top of the slab to stop the evaporation process.

Curing of Well Steining

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

Material Hopper

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.

4. FOUNDATIONS

Two types of foundations used for the project are:

1. Well foundation.

2. Open foundation/Pile 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’sown 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.

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.

Jack Down of well

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.

Gripper rods anchored into the ground

b. Supporting stools are then placed on the steining to suit the location of the anchors.

c. Pressurization girders are then erected over the stools and pressure plates fixed on top of the girders at

ends.

d. 250 MT capacity hydraulic jacks along with upper gripper attachments are erected and the gripper

rods are fixed by locking the upper gripper attachment.

e. 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.

f. All jacks are aligned and leveled properly.

g. The pressure hoses are connected with power pack and jacks.

h. Loading is applied with power pack.

i. After lifting of ram by about 40 to 100mm wedges are placed on bearing plates on either side of the

anchor couplers.

j. The lower gripper assembly is locked and upper gripper assembly is released.

k. Ram is brought to its original position and upper gripper assembly is locked.

l. Lower gripper assembly is then unlocked.

m. Now pressure is applied on the jacks and after lifting of about 400mm the point nos 10, 11, 12 and 13

is repeated. In case of Jacks Set No 1 the above locking and releasing will be automatically done after

initial setting of the Gripper rods.

n. 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.

Power Pack

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.

e) SINKING PROCEDURE

Formation of sump inside the well

a. 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.

2

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 / hump 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.

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.

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.

Rectifying by pulling 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.

Rectifying by pushing the well with jacks

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.

hollow casings for pile in well staining

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.

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 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 litre 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: [6]

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 (as per IS: 2911-1979).

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.

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.

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: [6] 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 excavation to the bottom of the casing pipe and then

suitable polymer system is added before further excavation.

d) 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.

5. 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. Two types of girders were used according to the requirement

I type and box type girder.

Figure 19: HSFGbolts 8.8 grade

Following procedure was followed while placing the girders at P19 for Insitu slab casting:

Figure 20: Placement of concret e blocks Figure 21: Main girder being placed

6. 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.

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 actual 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. This approach places an emphasis on three aspects:

1. Elements such as controls, job management, defined and well managed processes, performance and

integrity criteria, and identification of records

2. 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’squality control personnel.

Contractor’s that are under consideration to perform the work must submit their construction QAQC plans for

review and acceptance. The construction manager will 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.

7 . 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

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

1) 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.

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 millimetre. 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

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.

Cube specimen

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. [6]

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 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

CompressiveTest Machine

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