tech. specifications (civil & hm)

8/6/2019 Tech. Specifications (Civil & HM)

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SUPER HYDRO ELECTRIC PRIVATE LIM ITED

KHIRAO GANGA HYDRO ELECTRIC PROJECT

(2 2.0 MW)

UTTARAKHAND

TENDER DOCUMENT FOR CIVIL & HM WORKS

VOL. 2 DESIGN MEMORANDUM & TECHNICALSPECIFICATIONS

Consultants:M/ s Halcrow Consult ing India Private LimitedB-11, 2nd Floor, Sector-4,Noida-201301. (Uttar Pradesh)Tel.: +91-120 -4682500

Fax: +91-120-468-2534www.halcrow.com


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Khiraoganga Small Hydro Electric ProjectTender Documents

Specifications: Volume II A Civil

Page i

KHIRAOGANGA HYDRO ELECTRIC PROJECT

Volume II A

DESIGN MEMORANDUM AND

TECHNICAL SPECIFICATION

FOR

CIVIL WORKS


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Page ii

INDEX

PART 1: GENERAL AND PRELIMINARY ............................................................1101 Description of the Area..................................................................................1

102 General Description of the Project.................................................................1

103 Scope of work ................................................................................................1

104 Drawings........................................................................................................2

105 Site Installations.............................................................................................2

106 Construction Power........................................................................................2

107 Water Supply .................................................................................................3

108 Camps and Services .......................................................................................3

109 Communications ............................................................................................4

110 Waste Disposal...............................................................................................4

111 Materials on and under the Site .....................................................................4

112 Boundaries Cut Through................................................................................4113 Drains, Streams Watercourses etc .................................................................4

114 Compensation Water and Flow Past Structure ..............................................4

115 Keeping Works Free from Water...................................................................5

116 Slips ...............................................................................................................5

117 Protection of Completed Work ......................................................................5

118 Traffic ............................................................................................................5

119 Damage to Access Roads...............................................................................5

120 Setting Out .....................................................................................................5

121 Surface and River Bed Levels .......................................................................6

122 Testing Laboratory.........................................................................................6

123 Safety of Personnel ........................................................................................6124 Protection of the Environment.......................................................................6

125 Interference with Existing Works..................................................................7

126 Photographs ...................................................................................................7

PART 2: WORKMANSHIP AND MATERIALS ....................................................9

201 Workmanship and Materials in General ........................................................9

202 Inspection of Materials ..................................................................................9

203 Tolerances....................................................................................................10

PART 3: EXCAVATION AND EARTHWORKS ..................................................11

301 Definition of Earthworks Material...............................................................11

302 Site Clearance ..............................................................................................11

303 Excavation General...................................................................................11

304 Excavation Beyond True Lines and Levels .................................................12305 Approval of Excavations .............................................................................12

306 Excavations for Structures ...........................................................................13

307 Disposal of Surplus Excavated Materials ....................................................13

308 Procurement, Storage and Handling of Explosives .....................................13

309 Magazines ....................................................................................................14

310 Blasting ........................................................................................................14

311 Underground Excavations............................................................................15

312 Rockbolting..................................................................................................16


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313 Steel Rib Supports .......................................................................................18

314 Shotcreting ...................................................................................................19

315 Fill................................................................................................................21

316 Backfill to Structures ...................................................................................22

PART 4: CONCRETE...............................................................................................23

401 Cement .........................................................................................................23

402 Storage of Cement........................................................................................23

403 Fine Aggregate.............................................................................................23

404 Coarse Aggregate.........................................................................................24

405 Testing of Aggregates..................................................................................26

406 Aggregate Reactivity Potential ....................................................................26

407 Water............................................................................................................26

408 Admixtures...................................................................................................27

409 Concrete Mixes ............................................................................................27

410 Plum Concrete..............................................................................................27

411 Concrete Mix Designs .................................................................................28412 Trial Mixes...................................................................................................28

413 Works Test ...................................................................................................28

414 Test Failure ..................................................................................................29

415 Workability ..................................................................................................29

416 Concrete Returns and Records.....................................................................29

417 Batching and Mixing of Concrete................................................................30

418 Concrete Placing ..........................................................................................30

419 Concrete Placing Equipment .......................................................................31

420 Time for Placing Concrete...........................................................................31

421 Compaction..................................................................................................31

422 Placing in Inclement Weather......................................................................31

423 Placing in High Temperature.......................................................................31424 Formwork.....................................................................................................31

425 Preparation of Formwork.............................................................................32

426 Classes of Finish ..........................................................................................32

427 Removal of Formwork.................................................................................33

428 Construction Joints ......................................................................................33

429 Movement Joints..........................................................................................34

430 Steel Reinforcement.....................................................................................35

431 Storage of Reinforcement ............................................................................36

432 Cover to Reinforcement...............................................................................36

433 Curing and Protection ..................................................................................36

PART 5: MASONRY AND STONEWORK ...........................................................38501 Stone ............................................................................................................38

502 Masonry .......................................................................................................38

503 Random Rubble Masonry ............................................................................39

504 Masonry Lining to Waterways ....................................................................39

505 Stone Masonry Armouring to Weirs............................................................39

506 Dry Rubble Walling.....................................................................................41

507 Hand-placed Rubble Filling.........................................................................41

508 Rubble Filling ..............................................................................................41


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509 Gabions ........................................................................................................41

510 Rock Armouring and Rip-Rap.....................................................................42

511 Filter Fabric / Geotextile..............................................................................43

512 Gravel Filter .................................................................................................43

513 Stone Pitching ..............................................................................................43

PART 6: ROADWORKS ..........................................................................................45

601 Sub-grade Preparation..................................................................................45

602 Granular Sub Base (GSB)............................................................................45

603 Water Based Macadam (WBM) Road Surfacing.........................................45

604 Road Maintenance .......................................................................................46

PART 7: CULVERTS & DRAINAGE.....................................................................47

701 Culvert Material...........................................................................................47

702 Unloading and Laying out Pipes..................................................................47

703 Laying and Jointing Pipes............................................................................47

704 Installation ...................................................................................................47

705 Subsurface Drainage Slotted Plastic Pipework.........................................48PART 8: BUILDING FINISHING WORKS ..........................................................49

801 General.........................................................................................................49

802 Applicable Codes and Specifications ..........................................................49

803 Waterproofing Work....................................................................................50

804 Damp Proof Course......................................................................................51

805 Cement Plaster .............................................................................................51

806 Cement Pointing...........................................................................................52

807 Mosaic Flooring...........................................................................................52

808 Woodwork in Doors, Windows, Partition, Louvres, Railing etc.................52

809 Glazing and Metal Doors and Windows......................................................54

810 Painting ........................................................................................................55

811 Water Supply and Sanitary Works...............................................................55

812 Electrical Works ..........................................................................................56

813 Roof sheets and vertical cladding ................................................................57

814 Fencing.........................................................................................................57

PART 9: EARTH MAT .............................................................................................58

901 General Description .....................................................................................58

902 Earth Rods....................................................................................................58

PART 10: STEELWORK .........................................................................................59

1001 Hot Rolled Steel.......................................................................................59

1002 Surface Condition ....................................................................................59

1003 Structural Fasteners..................................................................................59

1004 Welding Consumables .............................................................................601005 Corrosion Protection System ...................................................................60

1006 General Workmanship .............................................................................60

1007 Welding Workmanship ............................................................................61

1008 Bolting Workmanship..............................................................................62

1009 Erection of Steelwork ..............................................................................62

1010 Protective Treatment - General................................................................62

1011 Protective Treatment - Particular.............................................................63

1012 Painting Handrails....................................................................................63


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Page v

Appendix A: Primary Survey Stations ...................................................................64

Appendix B: Table of Tolerances .............................................................................65


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Page 1

PART 1: GENERAL AND PRELIMINARY

101 Description of the Area

1)

The proposed Khiraoganga hydropower project is located near Benakuli village,Dist. Chamoli, Uttarakhand. The project is located on the river Khiraoganga on

Rishikesh- Badrinath road and is at a distance of about 298 km from Rishikesh. The

Powerhouse site is proposed to be located on the left bank of river Khiraoganga .

Diversion weir of the scheme is located about 0.6km upstream from confluence of

Alaknanda; Khiraoganga at Benakuli.

2) The topography of the project area is typically undulating, Himalayan with deepriver valleys and high ridges. The left bank of the river has thickly wooded forest,

and has a mixed usage as forest land as well as human habitation. Part of the right

bank area mostly belongs to private owners and is used for farming and rest of the

area is either barren or sparsely covered with shrubs or a forestland.

102 General Description of the Project

1) There is a motorable access road from Rishikesh to Badrinath via Srinagar,Ruderparyag, Chamoli, Joshimath, Lambagarh and to Benakuli .River Khirao

originates in the glacier regions of upper Himalayas. At present the project site is

approachable through a pedestrian suspension bridge about 50 meters down stream

of confluence of river Khirao and Alakananda.The barrage site of Vishnu Prayag

HEP is around 700 meters down stream from the confluence point. A path way

constituted the major approach for people of Lambagarh who shift their cattle during

summers to their summer village Khirao which is approximately 1.5 km from

suspension bridge.

103 Scope of work

1) The Works to be constructed under the Contract comprise the following components:1) Diversion Weir and Intake structure on the Khiraoganga River2) Intake Channel3) Desilting Basin4) Power Channel5) Tunnel in rock 2.5m diameter D shaped with concrete lined approximately

550m long.

6) Surge Tank 8m dia reinforced concrete surge tank.7) Penstock Valve House and Penstock Excavation in overburden with rock

outcrops for construction of penstock saddle support, crossings and anchor

blocks, Concrete framed valve house with boulder masonry or brickwork

infill walls. Casting in penstock pipe and transition (penstock, valves and

associated steelwork supplied and installed by others).

8) Surface Power House, Transformer and Switchyard Construction of surfacePower House and Tail Race and Surface Transformer and Switchyard civil

works (Electromechanical supply and installation by others).


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2) In addition, the Contractor shall construct such accommodation, plant yardworkshops, office, housing and camps for himself, his staff and employees as he

considers appropriate.

3) The scope of work shall also include all general and preparatory works and shallinclude work of any kind necessary for the due and satisfactory construction,

completion and maintenance of the Works in accordance with the Drawings and

these Specifications and further drawings and orders that may be issued by the

Engineer from time to time.

104 Drawings

1) The Works are shown on the Contract Drawings in Section 6 - Drawings2) Two copies of the Construction Drawings, shall be furnished free of cost to the

Contractor by the Engineer progressively according to the work programmesubmitted by the Contractor and accepted by the Engineer. Drawings for any

particular activity shall be issued to the Contractor at least 30 days in advance of the

scheduled date of the start of the activity.

3) Examination and /or approval by the Engineer of any drawings or other documentssubmitted by the Contractor shall not relieve the Contractor of his responsibilities or

liabilities under the Contract.

105 Site Installations

1) The extent of the areas of land which are to be made available by the Employer forthe use of the Contractor are as shown on the Drawings.

2) The Contractor shall be responsible for obtaining, at his own cost, any additionalareas of land he may require for his own temporary facilities or for the disposal of

spoil. Such areas shall be deemed to be part of the site.

3) Prior to the commencement of any work at the Site and not later than 28 days afterthe Date of Commencement, the Contractor shall submit to the Engineer for approval

detailed drawings showing the locations and details of his proposed installations,

facilities, plant, stockpiling and "waste" areas in order that such proposed

installations, facilities etc may be co-ordinated with the requirements of the Engineer

and other Contractors. The Contractor shall not commence any of the proposed

installations/facilities until the Engineer's approval has been obtained. Anysubsequent changes must be the subject of the Engineer's prior approval

.

106 Construction Power

1) The Contractor shall be responsible for providing construction power for his own useincluding all his site installations, offices, accommodation areas, workshops and

laboratory.


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2) The Contractor shall present drawings and plans of the installations to the Engineerand obtain his approval prior to the commencement of the work.

3) The Contractor shall be responsible for providing lighting and ventilation at allworking areas as required.

107 Water Supply

1) Water from the Khiraoganga River is suitable for construction purposes.2) The Contractor shall provide water for the Works, including potable water. This

provision shall include the construction of necessary reservoirs and piping to cover

all demand peaks at any time.

3) Prior to any installation, the Contractor shall submit to the Engineer for his approvala detailed description of the planned water supply system. The quality of, and the

designed pressure in, the water supply system shall be subject to the prior approval

of the Engineer.

108 Camps and Services

1) The Contractor shall provide camps for boarding, lodging and medical care for hisown personnel and those of his subcontractors.

2) The standards and regulations presently in force in India in respect of the treatmentof personnel, sanitation and accident prevention, shall duly be taken into account by

the Contractor. In the construction and maintenance of the camps and services, the

Contractor shall ensure that the camp and the buildings which form part of it are kept

in good hygienic condition.

3) The Contractor (including its sub-contractor) shall provide alternative fuelarrangement i.e. cooking gas/kerosene oil, electricity free of cost to all its canteen

/mess, labourers and staff working in the Project during the whole period of

construction activity to avoid felling of trees for use as firewood. In case alternative

fuel supply i.e. kerosene, gas, electricity is not available in the project area, the

Contractor shall approach the forest department/ forest corporation to open fuel

depot in the project area for meeting the demand for fuel wood.

4) The Contractor shall provide, maintain, and remove on completion adequate sanitaryfacilities to the approval of the Engineer. The Contractor shall prevent pollution of

the water supply and shall not discharge sewage which has not been properly treated

into natural streams/water courses etc.

5) The Contractor shall make arrangements for treatment on the Site of casualties andsick persons in first-aid units or in such other wards as may be necessary in

accordance with the appropriate Regulations. The Contractor shall provide and

maintain adequately equipped first aid stations at each of the main working areas.

6) The Contractor shall construct, equip and administer at his cost fire points in such


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positions and of such size as will provide an adequate service for the protection

against fire of all buildings, stores and property on the Site.

109 Communications

1) The Contractor shall provide telephone, and radio-telephone facilities as arenecessary to permit communication between the various Sites and the offices of the

Contractor.

110 Waste Disposal

1) For the disposal of all waste, the Contractor shall designate a suitably located tipwhich shall be subject to the prior approval of the Engineer. The Contractor shall

transport all waste to the tip and then incinerate and immediately bury it.

111 Materials on and under the Site

1) Materials arising from clearance of the Site, soil stripping and excavations shall notbe removed from the Site except as required by the Contract.

112 Boundaries Cut Through

1) Fences, walls, etc. crossed by the Works and forming boundaries of plots outside thearea occupied by the Works shall not be cut through or destroyed for more than the

distance necessary to permit the erection of new fencing etc. and the Contractor shall

make the ends of the cut fences secure. Where fences or walls are damaged or

destroyed, the whole shall be restored and reinstated with like materials to the

satisfaction of the owners, occupiers and the Engineer.

113 Drains, Streams Watercourses etc

1) Drains, pipes, canals, channels, water courses or streams affected by the Contractor'soperations shall be reinstated to their original condition. The Contractor shall notify

the Engineer in writing 14 days in advance of his intention to start any part of the

Works affecting watercourses, canals, streams, drains, pipes, channels etc. The

Contractor shall be responsible for maintaining the watercourses within the Site in

effective working condition. The Contractor shall take all practicable measures

(which shall be subject to the prior approval of the Engineer) to prevent the

deposition of silt or other materials in such watercourses etc from his operations.

114 Compensation Water and Flow Past Structure

1) The Contractor shall ensure that during the construction of weir and other structuresacross rivers and existing channels and up to the time of completion of the relevantparts of the Works, the whole flow of the rivers or channels shall be allowed to pass

the Works except for such quantity as the Contractor may reasonably require for the

execution of the Works, unless otherwise directed by the Engineer.

2) After completion of those parts of the Works or Temporary Works which form abarrier to river or channel, the Contractor will be required by the Engineer to pass

such quantities of water into the river or channel downstream of the structures as

may be directed. The Contractor shall not alter the rate of flow of such water except


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with the approval of the Engineer.

115 Keeping Works Free from Water

1) Except where underwater construction is required, the Contractor shall execute allwork in the dry, and shall construct any temporary diversion works, drains,pumping systems, and other works that may be necessary for the purpose. The

Contractor shall be responsible for the design of these temporary diversion works.

116 Slips

1) The Contractor shall make good any damage or defect caused by slips to anycuttings, excavations or embankments on the site and shall do all necessary work to

prevent or remedy the same.

117 Protection of Completed Work

1) The Contractor shall protect completed work from damage during subsequentoperations, from the weather or any other cause, including the naturally aggressive

nature of the environment in which the Works are to be constructed and make good

any damage so arising.

118 Traffic

1) Prior to commencing any work in or which may affect the use of any highway, theContractor shall obtain the written approval of his proposed methods of working and

traffic management plan from the Engineer and the Highway and the Police

Authorities. Throughout the duration of the Contract, the Contractor shall co-

operate with the Highway and Police Authorities concerning works in, or access to,

the highway. Any requirements of such Authorities shall be notified in writing by

the Contractor to the Engineer.

2) Where required, the Contractor shall provide and maintain all necessary temporarydiversions which shall be operational before interference with existing

carriageways, footways or public right of way. The Contractor shall remove all

temporary diversions and reinstate the original carriageway as soon as they are no

longer required

119 Damage to Access Roads

1) The Contractor shall ensure that damage to any public or private roads, footpathsand tracks used by any vehicles or plant proceeding to or from the Site is kept to a

minimum and he shall be responsible for the cost of all repairs necessary to restore

such roads, tracks or footpaths to the satisfaction of the Engineer and the owner

and/or controlling authorities.

120 Setting Out

1) The Contractor shall set out the Works according to the lines and levels shown onthe Drawings. . The coordinates and levels of the primary survey stations are given

in Appendix A to this Specification.


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2) The Contractor is to protect all survey stations and benchmarks from disturbance ordamage. Any stations or benchmarks that must be removed for construction of the

Works shall first be transferred to replacement points

121 Surface and River Bed Levels

1) Before commencing work on any section of the Works, the Contractor shall surveyand level the original ground surface and river-bed and shall prepare and submit to

the Engineer plans and sections for agreement.

2) At the commencement of the works the Contractor shall carry out a survey to checkthe levels and co-ordinates of the primary benchmarks relative to each other.

122 Testing Laboratory

1) The Contractor will establish and maintain throughout the period of construction asite laboratory. The laboratory shall be equipped to undertake all the tests on soil

and concrete required by the Specification. For other tests, the Contractor may utilisefacilities elsewhere in an approved laboratory which must be open for inspection by

the Engineer.

2) The Contractor shall, at his own cost, provide moulds, thermometer, slump testingequipment, labour, etc for the sampling of fresh concrete and the preparation and

storage of test samples. The Contractor shall deliver the samples together with the

sampling records to the laboratory 24 hours before the due date for testing.

123 Safety of Personnel

1) The Contractor shall be responsible for the safety of all personnel on the Site andshall provide his employees and his sub-contractors employees working on the Siteand all visitors to the Site with safety equipment appropriate to the tasks upon which

they are engaged, such as helmets, safety footwear, gloves, lamps, waterproof

clothing, dust masks and safety belts. The use of such safety equipment shall be

compulsory as deemed necessary by the Engineer.

2) The Contractor shall provide all lighting and ventilation necessary to ensure a safeand healthy environment for personnel in cases when personnel are working at

night, or in enclosed spaces.

124 Protection of the Environment

1) The Contractor shall take all precautions for safeguarding the environment duringthe course of the construction of the works. He shall abide by the laws, rules and

regulations in force governing pollution and environmental protection that are

applicable in the area where the works are situated.

2) The Contractor shall obtain materials from quarries or borrow pits only after theconsent of the Forest Department or other concerned authorities is obtained. The

quarry operations shall be undertaken within the rules and regulations in force.


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3) The Contractor shall ensure that appropriate procedures are complied with forcontrol of any materials used in the Works which are hazardous to the health of

persons, animals or vegetation. The procedures shall include, but not be limited to:

Spill containment & clear up Segregation and Storage Selection of low-impact materials where practicable. Provision of protective clothing & equipment for workers handling hazardous

materials.

4) The Contractor must take all reasonable steps to minimize nuisance from dust, noise,or other cause during the Construction of the works. Roads in frequent use with heavy

traffic shall be watered daily or more frequently if necessary to control dust. The

Contractor's attention is drawn to the damage to crops which may be caused by dust.

The Contractor is to take such measures as may be necessary to prevent such damage by

dust arising from the execution of the Contract.

5) All public roads used by the Contractor or any of his sub-contractors or suppliers ofmaterials or plant, shall be kept clean and clear of all dust/mud or other extraneous

materials dropped by the vehicles or arising from the Works.

6) Clearance shall be effected immediately by manual sweeping and removal of debris,or, of so directed by the Engineer, by mechanical sweeping and clearing equipment,

and all dust, mud and other debris shall be removed entirely from the road surface.

Additionally, if so directed by the Engineer, the road surface shall be hosed or

watered using suitable equipment.

7) The Contractor shall observe all agreements entered into by the Employer with anyperson or persons relating to occupation of the properties by the Employer and to theexecution of the Works thereon. The Contractor will be given on request copies of any

agreement or part thereof relating to such matters.

8) Compliance with the foregoing does not relieve the Contractor of any responsibilityfor complying with the requirements of any Highway Authority in respect of the

roads used by him.

125 Interference with Existing Works

1) The Contractor shall not interfere in any way with any existing works whether theproperty of the Employer or of a third party and whether the position of such works isindicated to the Contractor by the Engineer or not, except where such interference is

specifically described as part of the Works either in the Contract or in the Engineer's

instructions.

126 Photographs

1) Progress colour photographs shall be taken at such times and of such portions of theWorks as the Engineer may require. The Contractor shall supply five unmounted copies

of each photograph of an overall size of 250 mm x 200 mm. Each copy shall have its


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title, date and serial number printed in black on a 25 mm wide white margin along the

bottom edge. The negatives or digital files of the photographs shall be the property of

the Employer and no prints from these may be supplied to any person or persons except

with the written authority of the Engineer.


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PART 2: WORKMANSHIP AND MATERIALS

201 Workmanship and Materials in General

1) All workmanship shall be of the best quality appropriate to each category of work.Except where otherwise stated or approved by the Engineer, all materials used in theWorks shall be of the best quality of their respective kinds as specified or described in

the Specification, Drawings and Bills of Quantities and shall comply wherever possible

with the current issue of the appropriate standard published by the Indian Standards

Institution, or other equivalent national standard proposed by the Contractor and

approved by the Engineer.

2) Reference to Indian Standard Specifications or Codes of Practice in the Specification orBills of Quantities does not imply any bias in favour of equipment, fittings, finishing etc.

but is intended to indicate the standard acceptable to the Engineer. The Contractor may

relate his offer to other National Standards or Codes of Practice but shall explain the

system used and provide the Engineer with all the necessary information and

comparisons in English showing that his proposed standards are equivalent to thespecified Indian Standards or Codes of Practice. Six copies of such alternative standards

in English are to be supplied by the Contractor to the Engineer when required.

3) In all cases where the name of a particular type or make of plant or item is referred toon the Drawings or elsewhere in this Specification, this is intended to indicate only the

acceptable standard.

4) The Contractor may offer alternative plant or materials to that specified and in all suchcases the Contractor's offer shall be at least of equal quality. When alternatives are

offered the Contractor shall submit to the Engineer for approval, a statement detailing

the alternatives, and shall include full technical descriptions, drawings and

specifications, and shall provide such full information as is required to enable the

Contractor to demonstrate to the Engineer that the alternative is equivalent to the item

specified. Any further information that the Engineer may require shall be produced by

the Contractor when called for.

5) The Contractor shall use locally produced materials in preference to imported materialsprovided that they comply with the Specification and are available in sufficient and

timely quantities.

202 Inspection of Materials

1) The Engineer may employ an inspecting Engineer to inspect materials for the Works atthe suppliers' premises or elsewhere, and in this capacity the inspecting Engineer will beregarded as the Engineer's Representative with the limitation imposed by Clause 3 of

the Conditions of Contract.

2) Whenever work is to be done at a time when work is not usually in progress, orwhenever the regular period for carrying on such work is changed, the Engineer shall be

given notice in sufficient time to arrange for proper inspection.


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3) If required by the Engineer, the Contractor shall supply copies of orders placed by himfor materials to be incorporated in the Permanent Works so that inspection of the

relevant materials can be arranged in sufficient time if considered necessary by the

Engineer.

203 Tolerances

1) All works shall be constructed to the tolerances shown in the Appendix B of thisSpecification.


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PART 3: EXCAVATION AND EARTHWORKS

301 Definition of Earthworks Material

1) The following definitions of earthworks materials shall apply to this and otherClauses of the Specifications in which reference is made to the defined materials:

a) top soil shall mean the top layer of soil that can support vegetation;b) suitable material shall comprise all that material which arises from excavations

within the Sites and which is approved by the Engineer as acceptable for use in

the Works;

c) unsuitable material shall mean other than suitable material and shall comprise:i) material from swamps, marshes and bogs;ii) peat, logs, stumps and perishable materials;iii) material susceptible to spontaneous combustion;iv) clay of liquid limit exceeding 90 and/or plasticity index exceeding 65;

d) Common material shall mean all material other than that defined as rockhereunder;

e) Rock shall mean those geological strata or deposits as described in theContract, and any material requiring the use of blasting or approved pneumatic

tools for its removal, but excluding individual masses less than 1.0 cu.m.

302 Site Clearance

1) The Contractor shall clear the Site as required by demolishing and removingvegetation, debris, buildings etc and the like to approved locations as directed by the

Engineer. No access shall be permitted, or damage caused outside the area of the

Site.

2) As far as possible, trees greater then 150mm diameter shall be preserved, and no treegreater than 150mm diameter shall be felled without prior approval of the Engineer.3) Trunks, branches and stumps of trees shall be cleaned of limbs and roots and stacked.

Also boulders, stones and other materials suitable for re-use in the Works shall be

neatly stacked as directed by the Engineer.

4) Stumps and major roots shall be grubbed up and all combustible material arisingshall be gathered into windrows and burnt. The Contractor shall take precautions to

prevent the spread of fire to adjacent land.

303 Excavation General

1) Excavation shall be carried out to the lines, levels and profiles shown on theDrawings or to such other lines, levels and profiles as the Engineer may direct or

approve in writing. The work shall be carried out by the Contractor in such a way as

to avoid disturbance to the surrounding ground. Particular care shall be taken to

maintain stability when excavating in close proximity to existing works or natural

slopes.

2) The work shall be carried out in a careful manner to ensure that the exposed surfaces


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are as sound as the nature of the material permits and that no point shall protrude

inside the lines shown on the Drawings except as otherwise specified or agreed by

the Engineer. In soft excavation which is to remain open permanently, exposed faces

shall be formed accurately to the required slopes and profiles. Excavations in rock

which remain open permanently shall be so trimmed that no point protrudes within

the required profile.

3) The Contractor shall dispose of all material arising from excavations. If it is suitableand required for the Permanent Works it shall be placed directly in such Works or set

aside for use as and when required in suitable approved stockpiles, otherwise it shall

be disposed of in designated spoil areas.

4) The Contractor shall be responsible for keeping all excavations free from water fromwhatever cause arising, and shall provide such pumping capacity and other measures

as may be necessary for this purpose.

5) The Contractor shall properly support the sides of temporary excavations and shallbe responsible for their safety.

6) Slope support and slope protection to cut slopes that are to be permanently exposedshall be installed as directed or approved by the Engineer as excavation proceeds.

7) The Contractor shall notify the Engineer without delay of any permeable strata,fissures or unusual ground encountered during excavation.

8) Where blasting is required the blasting to final profiles shall be carried out using pre-splitting techniques.

304 Excavation Beyond True Lines and Levels1) If from any cause whatsoever excavations are carried out beyond their true line and

level, the Contractor shall make good to the required line and level with the

appropriate grade of filling to be contained in the true excavation, or with concrete or

other approved material in such a manner as the Engineer may direct.

305 Approval of Excavations

1) When excavations have been taken out accurately to the profiles or dimensionsrequired for the work, the Contractor shall inform the Engineer so that he may carry

out an inspection.

2) If, after inspection, the Engineer requires additional excavation to be carried out, theContractor shall do so to such new profiles or dimensions as the Engineer may direct.

3) The Contractor shall obtain approval of excavations prior to placing pavementlayers, fill or concrete.

4) The Contractor shall maintain open excavations in an approved condition, and shallrectify the effects of deterioration due to weather.


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306 Excavations for Structures

1) Open excavation to form foundations for a structure shall be carried out to the linesnecessary to permit the proper construction of the structure or as directed by the

Engineer.

2) If required, before any concrete for a foundation is placed, the bottom of theexcavation shall be re-compacted to achieve at least 95% of the maximum dry

density determined in accordance with (IS 2720 ( part 18).

3) The Contractor shall carry out the excavation in a safe manner such that the sides ofthe excavation are adequately supported and stable.

4) The excavation shall be excavated and supported by methods which will notendanger the stability of the surrounding slopes or works.

307 Disposal of Surplus Excavated Materials

1) Available spoil areas are to be used for disposal of surplus excavated materials.. Ifadditional areas are required, the Contractor shall be responsible for obtaining the

necessary approvals from the owners and the local authorities.

2) The Contractor shall organise and carry out the placing of spoil in such a way thatthe natural drainage to existing waterways is not impeded. Contamination of existing

waterways shall be avoided and suitable drainage shall be provided, if necessary.

3) Spoil material shall be placed in the spoil areas to form stable, free-draining banks.4) The Contractor shall submit to the Engineer for approval all necessary data showing

mucking areas, working methods and drainage and stabilizing provisions beforeplacing of spoil in any areas.

Excavation by Blasting

308 Procurement, Storage and Handling of Explosives

1) The Contractor will obtain the necessary licences for purchase and storage ofexplosives and detonators and shall be responsible for the acquisition, transport,

custody and storage of explosives.

2) The Contractor shall submit to the Engineer his proposals for the use of explosives inconnection with the Works and the programme for their procurement and transport to

site. .

3) The Contractor shall be responsible for the quality and satisfactory performance ofexplosives.

4) Only such quantities of explosives and sundries as are required for the working dayshall be released from the magazine and the Contractor shall not store additional

explosives and ancillary components elsewhere. Any unused materials shall be


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returned to the magazine and recorded accordingly.

309 Magazines

1) The Contractor will establish, operate and maintain the magazine for the storage ofhis explosives.

310 Blasting

1) When blasting is permitted, it shall be carried out only after the Contractor hasprovided adequate visible and audible warning systems, safety men and all such

measures as are necessary to prevent injury to persons and property and protect the

Works from damage during blasting, and shall be carried out with the greatest care,

strictly according to the arrangements approved by the appropriate Authority.

2) The Contractor may choose his own methods for drilling and blasting rock subject tothe approval of the Engineer.

3) Only workmen who are in possession of a blasting certificate valid for the type ofblasting to be carried out shall be permitted to be in charge of blasting operations.

4) All charging of drill holes, type of detonation, etc, shall be in accordance withmodern methods and recognised good practice.

5) If the prevalence of electrical storms makes it unsafe to use electrical firing inblasting operations the Contractor shall use an alternative type of firing.

6) The Contractor shall take all necessary precautions with respect to the use ofelectrical detonators in the vicinity of static and mobile radio transmitters including

normal radio and television broadcasting stations and radar units associated withaircraft movements.

7) A register of all explosives used, firing amounts and location shall be maintained bythe Contractor and be available at all times to the Engineer for checking.

8) The use of explosives will not normally be permitted within 15m of any structure orpart of a structure. Where permission to use explosives is withheld, the Contractor

will not be entitled to any additional payment in respect of alternative methods

necessary for carrying out the work.

9) When blasting within 15m of a structure(s) is permitted it shall be carried out bysmall charges and /or milli-second delay fuses in such a manner as to reduce thelevel of vibration occurring which the Engineer may require to measure. Care shall

be taken that blasting does not open fissures in the rock or overburden under or

adjacent to parts of the Works.

10)Where blasting is proposed adjacent to a building or other structures existing orunder construction, the Contractor shall satisfy the Engineer that safe values of

vibrational amplitude and peak particle velocity will not be exceeded.


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11)Where required by the Engineer, the Contractor shall employ heavy mesh blastingnets or other approved means to limit the scatter of debris and flying particles.

12)Blasting shall be restricted to such periods as the Engineer may prescribe.311 Underground Excavations

1) The method and procedures for excavation in tunnel by tunnelling methods coveredunder these specifications shall conform to latest revisions of the following Indian

Standards specifications or any International recognised standards.

IS 4756 Safety code for tunnelling work

IS 5878 Code of Practice for construction of tunnels conveying water:

(Part - I Precision Survey and Setting Out).

IS-5878 Code of Practice for Construction of Tunnel conveying water:

(Part 2 - Underground Excavation in Rock) Section I Drilling &Blasting

IS 5878 Code of Practice for construction of tunnels conveying water.

(Part 2 - Underground excavation in rock) Section 2- Ventilating,

lighting, mucking and dewatering.

IS 5878 Code of Practice for construction of tunnels conveying water.

(Part 2 - Underground excavation in rock) Section 3- Tunnelling

method for steeply inclined tunnels, shafts and underground

power houses

IS 5878 Code of Practice for construction of tunnels conveying water:(Part -3 Underground excavation in soft strata)

IS 5878 Code of Practice for construction of tunnels conveying water:

(Part - 4 Tunnel Supports)

IS 7209 General requirements for blast hole drilling rigs

2) The Clearance Line is shown on the drawings. It defines the minimum dimensions ofthe clear opening which is obtained after excavation and installation of any required

support system. The ends of rockbolts may be permitted to protrude inside the

Clearance Line where concrete linings are provided. Otherwise, no projection will bepermitted within the Clearance Line without the written consent of the Engineer.

3) The quantity of excavation to be measured and paid for at the unit rate will be thequantity included within the Clearance Line plus the thickness of any permanent

support system.


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4) The drilling pattern shall be such as to minimize over excavation, and also to causeleast disturbance to or shattering of surrounding rock mass. The drilling pattern shall

be adjusted to suit the geological conditions of rock strata.

5) Blasting shall be controlled and conducted in such a manner, not to endanger anyadjacent property or structures and as not to affect or hinder the progress ofadjoining works. The type of explosives to be used and the quantity of charge shall

be adjusted to suit the geological conditions of rock strata. The rules in force for

handling, transporting and storing explosives (as laid down in the Indian Explosives

Act or any other Act having the force of law) shall be strictly adhered to.

6) After blasting, the whole surface of excavation shall be carefully examined and allloose rock and projections etc., removed in such a way that there shall not be any

danger of any piece of rock falling down subsequently; due to any cause whatsoever.

After the section is excavated, it shall be carefully trimmed to remove any

projections that may be found within the profile defined by the Clearance Line.

Geological mapping of the faces shall be prepared by the Contractor for every round

of blasting operation.

7) The whole excavated reach of the Tunnel shall be properly ventilated, either byartificial means or by natural draft. The Contractor shall provide at his own cost,

ventilation fans of adequate capacity and ducts of suitable size to force in air into the

tunnel during working hours. The fans shall be of the reversible type so that the

gases released after blasting shall be sucked out of the tunnel in the shortest possible

time.

8) The workmen shall not be allowed to enter and start work unless and until all theobjectionable gases are removed to the extent considered safe and satisfactory.

9) The capacity of the ventilation plant shall be adequate to allow the removal of blastgases within as short a time as possible to allow starting of mucking operations

commensurate with the schedule of progress of work.

10)The entire length of Tunnel excavated shall be adequately illuminated by electriclights in accordance with IS: 5878-Part-2-Section-2. The working face and the

working area shall be brightly illuminated either by adequate floodlights or by other

means. The facility of lights in the tunnel shall also be made available for the use of

inspecting officers and any visitors, if required, during non-working hours, at no

extra cost. In addition every workman, working inside the tunnel shall have a battery

operated torch either fixed to the helmet or hand held.

312 Rockbolting

1) This specification covers supply and installation of rock bolts and associated worksconforming to I.S.1570 (PART-1):1978 or latest edition.

2) Rock bolts shall be 25mm diameter mild steel deformed bar threaded at one end asshown in the drawings. The length of the rock bolts and pattern in which the rock

bolts shall be installed shall be as shown in the drawings or as otherwise prescribed


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by the Engineer. Rock bolts shall have a tensile strength of 410 MPa and minimum

yield strength of 250 MPa and minimum elongation of 23 percent and they shall be

threaded. All nuts for the rock bolts shall be heavy duty hexagonal, double chamfered

confirming to black hexagon bolts, nuts and lock nuts and black hexagon screw IS

1363-1967 or the subsequent revision.

3) Bearing plates shall be flat steel square plates 150 mm X 150 mm X 10 mm andconforming to Structural steel (standard quality) IS 2062:1992 or its subsequent

revision. For the purpose of grouting the flat steel bearing plates shall have separate

holes for the grout tubes.

4) Cement for grout shall be ordinary Portland cement confirming to Ordinary and lowheat Portland cement IS8112-1989 or its subsequent revision. The average fineness

value of the cement shall not be less than 4,500 square centimetres per gram.

5) Rock bolts shall be installed as soon as possible after each blasting. The Contractorshall be well prepared to perform such work and the equipment used for that workshall allow the Contractor to insert the rock bolts up to the face with the necessary

speed and accuracy and if possible, without removing the recently excavated material

to install them. Any rock bolts that are affected by subsequent blasting shall be

replaced by new rock bolts installed nearby.

6) The diameter and depths of drilled holes and the method of cleaning the same forrock bolts shall be such as will promote effective anchoring and grouting of the rock

bolts and ensure that the inner end of the rock bolts does not protrude beyond the

Clearance Line by more than 70mm.

7) Once the drilling is completed, the bore holes shall be cleaned by means of water andair under pressure in order to remove small particles of rock or dust remaining in it,

so that the hole is perfectly cleaned before the insertion of the rock bolt.

8) Holes for rock bolts shall generally be drilled normal to the Clearance Line unlessotherwise shown on the drawings or ordered by the Engineer. The actual position of

the rock bolts shall be chosen such that the shank is not bent or stressed due to

excessive inclination between the rock face and the shank. The direction of bolts

shall be modified to suit the rock jointing pattern as observed at site on excavation as

per the instructions of the Engineer and rock bolt spacing shall be adjusted locally tosuit the joint spacing and pattern.

9) In general, cement capsule anchors shall be used. Where separate grouting isapproved by the Engineer, bolts shall have the grouting tube attached. The Contractor

shall supply plastic piping in rolls which shall be cut and attached to the bolts with

adhesive tape or another approved method. .


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10)Grout for rockbolting shall be made up of portland cement and water with a water-cement ratio of approximately 0.4 by weight to which aluminium powder shall be

added if required in a proportion indicated by the engineer.

11)Unless otherwise directed or approved commercial grade extra fine aluminiumpowder in an amount not exceeding 0.005 % by mass of cement shall be blended

with the cement to ensure the necessary expansion of grout.

12)Grouting shall be applied at a moderated pressure (2kg/cm2) unless indicatedotherwise until the voids between the bolts and the rock are completely filled. As

soon as the grouting is finished, the grouting holes shall be plugged to avoid leakage

of grout.

313 Steel Rib Supports

1) The Contractor shall maintain a minimum stock of 10 (ten) complete ribs and theirassociated fittings at Site to allow immediate installation in cases where unstablerock conditions are encountered.

2) The method and procedures for providing and fixing steel ribs covered under thesespecifications shall conform to latest revisions of the following Indian Standard

Specifications or any International recognised standards.

IS 800 Code of Practice for general construction in steel.

IS 808 Dimensions for hot rolled steel beams, column, and channel and

angle section.

IS 2062 Specification for Weld able Structural Steel.

IS 4756 Safety code for tunnelling work.

IS 4880 Code of practice for design of tunnels conveying water-

(Part-VI) Tunnel Supports.

IS 5878 Code of Practice for construction of tunnels conveying water

(Part IV) Tunnel Supports.

3) Ribs shall be placed such that the inner face is not inside the Clearance Line. Anyextra excavation necessary for placing these supports shall be paid for at the same

rate as the main excavation. The exact type, design and extent of permanent supports,

required in the tunnel shall be proposed by the Contractor based on the condition of

rock and the likely rock loads and subject to approval by the Engineer.. The rib

support system shall include anchoring if required, lagging, supporting, wedging, etc.

to ensure proper supporting of excavated surface.


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314 Shotcreting

1) All methods and procedures for providing and installing shotcrete and wire meshreinforcement shall conform to Indian Standard specifications and other publications

listed below unless otherwise specified.

Indian Standards

IS 8112 - 1989 Specification for 43 grade ordinary Portland cement. (First Revision).

IS1566-1982 Specification for Hand Drawn Steel wire fabric for concrete

reinforcement.

IS 1570 (Part-I): 1978 Steel specified by Tensile and/or yield properties.

IS 9012- 1978 Recommended practice for shotcreting/ latest publication, if any.

2) Water to be used for shotcreting shall confirm to requirement given in IS 456: 1978.3) Sand for shotcrete shall comply with the requirements given in IS : 383:1970 and

graded evenly from fine to coarse as per Zone II and Zone III grading of IS

383:1970.

4) Coarse aggregates shall comply with the requirements of IS: 383-1970. It shall,generally confirm to one of the grading given below. The maximum size of coarse

aggregate to be used shall be restricted to 12.5 mm.

Grading of Coarse Aggregates

Percentage by Mass Passing for Aggregate

of Nominal Maximum Size

IS Sieve

Designation (mm)

10 mm 12.5 mm

25 - -

20 - 100

12.5 100 90-100

10 85-100 40-70

4.75 10-30 0-15

2.36 0-10 0-5

1.18 0-5 -

All oversize pieces shall be rejected by screening, since they are likely to cause

blockages in the equipment.

5) Admixtures shall be in accordance with the requirements of IS 9103 : 1979 and asapproved by the Engineer. The proportion of admixture (as a percentage of cement)


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shall be approved by the Engineer. Admixtures containing chlorides will not be

permitted.

6) Batching and MixingThe ingredients of the mix for shotcrete and strength criteria shall be as follows

i) Aggregates shall be well graded to achieve good pumpability through thespraying nozzle and the maximum size of coarse aggregate shall be limited to

12.5 mm, generally the mix design shall constitute one part of cement, one part

of sand (fineness modules of 2.4 and above) and two parts of well graded

aggregate however the mix proportions may vary as required by the Engineer.

ii) Shotcrete mix design shall ensure 28 day characteristic compressive strength ofover 25 MPa (25 N/mm

2).

iii) Water cement ratio for shotcrete in place shall be in the range of 0.35 to 0.40 bymass. The water content of the mix shall be limited to prevent sloughing.

iv) The rate of gain of strength of shotcrete shall conform to the followingcompressive strength requirements.

Age Compressive Strength

of Shotcrete (MPa)

1 hour 0.2

2 hours 0.50 0.75

8 hours 4.00 4.5012 hours 5.00

24 hours 10.00 11.00

72 hours 12.00 12.50

7 days 17.00 17.50

28 days > 25

v) The cement to be used for shotcrete shall be weighed first before mixing with thecoarse and fine aggregate. Every batch of concrete for shotcrete shall be

prepared for 50 Kgs of cement or whole multiple thereof. The Contractor shall

use weighing equipment to the accuracy of 0.1 kg to measure weight of cement

added in each batch.

vi)Mixed dry aggregate and cement, which do not contain a set acceleratingadmixture and which are not placed with in 30 minutes after mixing, shall be

discarded. Mixed dry ingredients, which contain a set accelerating admixture

shall be discarded if they are not placed within the time as determined by the


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Engineer depending on the moisture content of the mix and the amount of

admixture.

vii) Mix proportions shall be adjusted as necessary to obtain the required strength ofshotcrete and to keep rebound to the minimum.

7) Air and water shall be provided in such volume and under such pressure as may benecessary for the best operating conditions. In applying shotcrete, the discharge

nozzle shall be held in such a way that the stream of material shall impinge as nearly

as possible at the optimum angle to the surface for minimum rebound, and the

velocity of the discharge from the nozzle. The distance of the nozzle from the surface

and the amount of water used in the mix shall be regulated so as to produce a coating

with a minimum rebound of the material, with no sagging. Obstructions, such as

service lines, shall be removed to enable direct application of shotcrete to the

surfaces. Rebound material shall not be used again, but shall be removed from the

work and disposed of by the Contractor. During application of shotcrete theContractor shall provide adequate ventilation facilities and take such other measures

as are necessary for safety of his workmen including provision of face protection for

nozzle men.

8) The locations where shotcrete is to be used shall be as shown on the drawings or asdirected by the Engineer. Where shotcrete is to be applied, the Contractor shall clean

and prepare the surface by removing loose or shattered rock, rock debris, clay or

other loose materials. The surface shall be washed, where required, with a strong air

and water jet or by other means approved by the Engineer.

9) Nozzle men shall have had sufficient previous experience in the application of coarseaggregate shotcrete or shall work under the immediate supervision of a foreman or

instructor having such experience.

10)Alkali hydroxides and other chemicals contained in shotcrete admixtures aremoderately toxic and can cause skin and respiratory irritation unless adequate safety

measures are taken. In applying shotcrete containing toxic admixtures, the nozzle

men and helpers shall wear appropriate hoods to protect them against toxic or

objectionable material.

11)Gloves and necessary protective clothing shall be worn to protect against dermatitis.

315 Fill

1) Material for filling shall be obtained from approved sources or selected fromexcavations containing no vegetable or perishable matter, graded to ensure a dense

stable and homogeneous fill when compacted.

2) Fill shall be placed in layers not exceeding 250mm thickness, each layer being


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scarified and thoroughly compacted by four passes of a vibratory steel drum roller

with a static drum weight of at least 7 tonnes. Unless otherwise specified,

compaction shall be not less than 90% of the laboratory maximum dry density as

determined in accordance with IS 2720 (part 18).

3) In places where space restriction prevents the use of compaction equipmentmentioned above, the compaction shall be carried out by means of approved small

size equipment. If necessary the thickness of layers shall be adjusted in order to

achieve the same degree of compaction as with normal equipment

4) The fill material prior to compaction shall be brought to a moisture content withinthe range 2% of optimum. If watering is required it shall be carried out in such a

manner as to ensure the even distribution of water throughout the layer to be

compacted and the compaction operations will follow whilst the moisture content

remains within the specified range.

5) The Contractor shall take all necessary measures to prevent any damage or defects tothe Works which may be caused by settlements, slips or falls of embankments and

shall make good such damage or defects as may occur, to the satisfaction of the

Engineer.

6) Any instability of any adjacent excavation or slopes resulting from the embankmentnot being formed to the lines, levels and profile shown in the drawings or as ordered

by the Engineer will be the responsibility of the Contractor.

7) All fill materials shall be handled in such a way that they are un-segregated oncethey are in their final positions.

316 Backfill to Structures1) Backfill shall generally be selected material from excavation, approved by the

Engineer.

2) Material shall be moisture conditioned and then compacted to provide not less than95% of the laboratory maximum dry density as determined in accordance with IS

2720 (part 18).

3) The Contractors proposed method of working for compaction around structuresshall be subject to prior approval by the Engineer.


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PART 4: CONCRETE

401 Cement

1) Cement shall generally be Pozzolana Portland Cement (or Ordinary Portland Cementas an alternative)..

2) Cement procured by the Contractor in sealed bags, marked with manufacturersname, shall be delivered to the Contractors storage facility and shall be protected

from the weather by approved coverings. Damp bags shall be rejected.

3) The Contractor shall ensure that the arrangements for the storage of the cement onthe Site as hereinafter specified are sufficient for the segregation and identification of

each consignment.

4) No cement shall be used in the Works until it has been passed as satisfactory by theEngineer.

5) Where designated by the Engineer, fly ash (Pulverised fuel ash) conforming toGrade-1 of IS:3812 may be used as a part replacement of ordinary portland cement

provided uniform blending with cement is ensured and that the design mix gives

required strength to concrete within the required period.

402 Storage of Cement

1) While being unloaded and during transit to the concrete mixers, whether conveyed invehicles or by mechanical means, the cement must be protected from the weather by

effective coverings.

2) Cement in bags shall be stored in weatherproof and well-ventilated sheds. Ondelivery at the Site the cement is at once to be placed in these sheds and shall be usedin the order in which it has been delivered.

3) The Contractor shall be responsible for damage to cement bags while unloading andtransporting around the Site and in no case shall cement from a damaged bag or

hardened lumps be used in any of the Permanent Work.

403 Fine Aggregate

1) Fine aggregate for concrete shall be clean sand complying with (IS 2386 part 1 topart 8). The sand shall be from approved sources and sand which, in the opinion of

the Engineer, is not clean shall be washed before use.

2) The fine aggregate shall be free from salt, alkali, calcium sulphate or vegetablematter. It shall not contain more than 0.5 percent by weight of clay lumps.

3) Fine aggregate shall be capable of passing through a 5mm test sieve and shall begraded so that when mixed with the coarse aggregate and cement a concrete of

maximum density is produced. It shall not contain appreciable amounts of flaky or

elongated particles.


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4) The grading of fine aggregate shall comply with one of the Coarse, Medium or Fineclassifications as given below. In the event that the grading of the sand changes to a

different classification from that used when concrete mixes were designed and

approved, new trial mixes shall be carried out.

Sieve size Percentage by mass passing IS sieve

Overall Additional limits for grading

Limits Coarse Medium Fine

10.00 mm 100

5.00 mm 89 to 100

2.36 mm 60 to 80 60 to 100 65 to 100 80 to 100

1.18 mm 30 to 100 30 to 90 45 to 100 70 to 100

600 m 15 to 100 15 to 54 25 to 80 55 to 100

300 m 5 to 70 5 to 40 5 to 48 5 to 70150 m 0 to 15

5) Crushed sand may be added to natural sand in approved proportions in order toachieve the required grading. Crushed sand alone may not be used without approval.

The amount of material passing a 75 micron sieve shall not exceed 3% by weight.

6) When subject to five cycles of the soundness test specified in IS 1607 : 1977, fineaggregate shall show a loss not exceeding 10% when magnesium sulphate solution is

used.

7) Sand for mortar shall comply with IS 2386 Part 1 to Part 5.404 Coarse Aggregate

1) Coarse aggregate for concrete and other purposes shall comply with (IS 2386 part 1to part 8). It may be either natural gravel or stone broken to the desired size and shall

be obtained from quarries, pits or other sources approved by the Engineer.

2) Gravel or ballast shall be free from clay, earth, loam or other organic or similarmaterial and shall be approved by the Engineer. Any sand in the bulk gravel shall,

unless otherwise directed, be removed by screening and if required kept apart. Thesand thus obtained may be used in concrete provided that in the opinion of the

Engineer, it complies with the specifications for sand in the preceding Clause. Gravel

or ballast which, in the opinion of the Engineer, is not clean shall be thoroughly

washed before use.

3) Broken stone shall be of hard durable rock. Notwithstanding approval by theEngineer of its source, the stone as delivered to the Works will be subject to rejection

if for any reason the Engineer considers it unsatisfactory. It must be perfectly clean


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and no soft, clayey, shaley or decomposed stone will be approved. The stone must be

broken in a stone crusher of approved type to the sizes hereinafter specified and any

dust or fine material below 5 mm in size made in the stone crusher is to be removed

by screening if so required and, if the Engineer so orders, the stone shall be

thoroughly washed by an approved method.

4) When so required and before construction commences, laboratory tests shall be madeof the aggregates to be used on the Works will be undertaken by the Employer to

establish their suitability for concrete. In addition to these laboratory tests the

Engineer may require check tests of actual deliveries to be made at the Site from

time to time.

5) The grading of coarse aggregate shall comply with the appropriate classification asgiven below.

6) Coarse aggregate shall be graded so that when mixed with the approved fineaggregate and cement, a workable concrete of maximum density is produced.

7) The amount of material passing a 75 micron test sieve shall not exceed 1% byweight.

8) When subjected to five cycles of the soundness test specified in IS 1607, coarseaggregate shall not show a loss exceeding 10% when magnesium sulphate solution is

used.

9) The flakiness and elongation indices of the predominant size fractions in each singlesized coarse aggregate, determined in accordance with BS 812, shall not exceed 20%

and 35% by weight respectively.

Coarse Aggregate Grading

Sieve Percentage by mass passing BS sieves for nominal sizes

size Graded aggregate Single-sized aggregate

40mm 20mm 14mm

mm - 5mm -5mm -5mm 40mm 20mm 14mm 10mm 5mm

50.0 100 - - 100 - - - -

37.5 90-100 100 - 85-100 - - - -

20.0 35-70 90-100 - 0-25 85-100 100 - -

14.0 25-55 40-80 90-100 - 0-70 85-100 100 -

10.0 10-40 30-60 50-85 0-5 0-25 0-50 85-100 100

5.0 0-5 0-10 0-10 - 0-5 0-10 0-25 45-100

2.36 - - - - - - 0-5 0-30


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405 Testing of Aggregates

1) Aggregates will be tested in accordance with the following schedule and shallcomply with the stated limits

Acceptable LimitsTest Frequency

Coarse

aggregate

Fine aggregate

Grading weekly 4% from the design mix target

Magnesium sulphate

soundness (ASTM C88)

monthly 10% 10%

Water absorption weekly 2% 2%

Clay, silt and dust

content

weekly 1% 3%

Organic impurities

(ASTM C40, C87)

monthly 1% 3%

Sulphate and

Chloride

weekly 0.4%

0.05%

0.4%

0.1%

Aggregate crushing

value

weekly 20% n/a

Flakiness and

Elongation

weekly 20%

35%

n/a

Moisture content twice daily* 3 times daily*

* daily during dry season. Mix proportions to be adjusted to

compensate for moisture content of aggregates

406 Aggregate Reactivity Potential

1) Aggregate shall not contain any materials that are reactive with alkalis in theaggregate itself or in the cement, the mixing water or in water in contact with the

finished concrete or mortar in amounts sufficient to cause excessive localised or

general expansion of the concrete mortar.

2) The Contractor shall assess an aggregate source by testing in accordance with IS2386 Part 1 to Part 8 and the results shall comply with the limits given in the relevant

Indian Codes for overall effect on the permanent works mixes, before use of the

aggregate is approved.

407 Water

1) Clean fresh water is to be used for the mixing of all concrete and mortar, and is to befrom a source approved by the Engineer. Khiraoganga river water free from silt and

debris has been determined to be satisfactory. If required by the Engineer, samples

shall be taken from any other proposed source of supply and submitted to a

nominated laboratory for testing in accordance with IS 3025 (part 17, 18, 24 and 32)

and on the results of these tests the Engineer will decide whether the source is

acceptable.


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2) The acid soluble sulphate (SO3) content shall not exceed 500 mg/l and the acidsoluble chloride as NaCl (Cl x 1.65 = NaCl) content shall not exceed 600 mg/l. Tests

to establish the contents shall be carried out at monthly intervals.

408 Admixtures

1) Admixtures shall not be used in concrete without the Engineers approval.Admixtures containing chloride or other corrosive agents shall not be used.

2) Where the mix design utilises admixtures, they shall be used in the correct quantitiesin accordance with the manufacturers recommendations. Approved equipment and

methods shall be used for dispensing and incorporating the admixture in the

concrete; the dispensing unit shall be designed so that the discharge of the admixture

visible and is automatic in each batch.

3) The concrete tests described herein shall be conducted with the admixtureincorporated to establish that specified strengths are achieved, and that densities arenot reduced. If air entraining agents are used the density shall not be reduced by

more than 5%.

4) Set retarding and water-reducing admixture shall consist of lignosulphonate. Airentraining agents shall consist of neutralised vinsol resin.

409 Concrete Mixes

Concrete shall be as shown below

ConcreteGrade

CharacteristicStrength at

28 days

MaximumAggregate

Size

MinimumQuantity of

Cement

Maximum FreeWater-Cement

Ratio

TargetSlump

N/mm2

mm Kg/m3

mm

M40 40 20 375 0.50 75

M25 25 20 350 0.50 75

M25/12 25 12 350 0.50 75

M20/20 20 20 330 0.50 75

M20/40 20 40 300 0.55 75

M15 15 20 240 0.60 75

M10/20 10 20 130 -

M10/40 10 40 130 -

410 Plum Concrete

1) Plums shall be hard clean natural stones embedded in mass concrete, Class M20/40,


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during the placing of the concrete. The plums shall not be larger than one third of

the cross section of the concrete, with a maximum size of 300mm and should not be

placed closer than 50mm to each other. The volume of plums shall not exceed

twenty five per cent (25%) of the mass concrete volume and care shall be taken to

ensure that the minimum concrete cover over any plum is 75mm.

411 Concrete Mix Designs

1) Preliminary tests will be carried out by the Contractors laboratory to determine themixes which will satisfy the Specification with the available materials. These mixes

will be designed with due regard for the workability necessary to allow the

Contractor to place and compact the concrete with the equipment he proposes to use

in any particular situation.

2) The mixes will be designed to have mean strengths that are greater than the specifiedcharacteristic cube strengths by a margin of 1.64 times the standard deviation

expected from the concreting plant. The standard deviation will be calculated from

at least 40 individual cube results each representing separate batches of similarconcrete produced by the same plant and under the same supervision except that no

standard deviation less than 2.5 N/mm2

shall be used as a basis for designing a mix.

A standard deviation of 5N/mm2

shall be used for initial mix design purposes.

412 Trial Mixes

1) Trial mixes shall be prepared under full scale conditions and tested in accordancewith (IS 9013 : 1978). Trial mixes shall be made subsequently whenever a change is

intended in materials or in the proportions of the materials to be used.

Representative samples of the materials to be used shall be taken and three trial

mixes using the proposed proportions shall be made on different days. The

workability of each of these three mixes shall be determined by measurement ofslump and a batch of six cubes from each mix shall be made, three for tests at 7 days

and three for tests at 28 days. The Engineer will normally approve the proposed mix

proportions provided the average strength of the three trial mixes is not less than the

designed mean strength minus the designed standard deviation and subject to the

conditions noted below. Further trial mixes shall be made if the range of strength

that is the maximum minus the minimum, of the three cube results in any batch

exceeds 15% of the average of that batch, or if the range of the three batch averages

exceeds 20% of the overall average of the batches.

413 Works Test

1) Test cubes shall be made by the Contractor and cured, stored and transported to thelaboratory in accordance with IS 9013: 1978. The cubes shall be tested in

compression at the Contractors laboratory. The method of compacting cubes by

vibration shall be subject to the approval of the Engineer

2) A sample of concrete shall be taken at random each day of concrete of each grademade. The number of samples per day and the time when they shall be taken shall be

varied at random or as directed by the Engineer.


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3) From each sample two cubes shall be made for testing at twenty eight (28) days andone for testing at seven (7) days for control purposes.

414 Test Failure

1) Shou