Construction, Operation & Maintenance of Dalbari … Technical... · Construction, Operation & Maintenance of Dalbari ... BS British Standards ... 3.6.1 Scaffolding (Falsework) 46

Royal Government of Bhutan

Ministry of Works and Human Settlement

Department of Roads

Construction, Operation & Maintenance of Dalbari –

Dagapela Secondary National Highway (0.000 - 80.580

km)

Volume II

PARTICULAR TECHNICAL SPECIFICATIONS FOR BRIDGE

WORKS

Section A: Dalbari-Odalthang

Page 1 of 69

Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)

ABBREVIATIONS

AASHTO American Association of State Highway and Transportation Officials AC Asphalt Concrete ACV Aggregate Crushing Value AIV Aggregate Impact Value ALD Average Least Dimension ASTM American Society of Testing and Materials BOQ Bill of Quantities BS British Standards BSCP British Standards Code of Practice BSR Bhutan Schedule of Rates CBR California Bearing Ratio c/c center to center CR Crushing Ratio Cu.m Cubic metre DCP Dynamic Cone Penetrometer DoFS Department of Forestry Services DOR Department of Roads DGM Department of Geology and Mines dia Diameter ECOP Environment Code of Practice for Highways and Roads EMP Environmental Management Plan FI Flakiness Index GCC General Conditions of Contract HMAC Hot mix asphalt concrete HWL High Water Level IRC Indian Road Congress (i.e. Recommended Code of Practice by IRC) IS Indian Standards ISO International Organization for Standardization LAA Los Angeles Abrasion Value LWL Low Water Level MC Moisture Content MDD Maximum Dry Density min Minute MSL Mean Sea Level NEC National Environment Commission no Number (units), as in 6 no. No Number (order) as in No 6 OMC Optimum Moisture Content OPC Ordinary Portland Cement PCC Particular Conditions of Contract PI Plasticity Index PL Plastic Limit PM Plasticity Modulus (PI x % passing 0.425 mm sieve) PVC Polyvinyle Chloride QA Quality Assurance PS Provisional Sum QC Quality Control

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RGoB Royal Government of Bhutan

RROW Road Right of Way

SE Sand Equivalent

sec Second

SG Specific Gravity

SI International Standard Units of Measurements

SSS Sodium Sulphate Soundness test, loss on 5 cycles

STV Standard Tar Viscosity

Sq.m Square metre

TS Tensile Strength

UC Uniformity Coefficient

UCS Unconfined Compressive Strength

VIM Voids in Mix

w/c Water cement ratio

Wt Weight

% Percent

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Table of Contents

1.0 SECTION 1: GENERAL AND SITE ESTABLISHMENTS 9

1.1 General 9

1.1.1 Scope of Work 9

1.1.2 Site Acquaintance 9

1.1.3 Specifications 9

1.1.4 Reference to Bureau of Indian Standards Codes & Other Codes 9

1.1.5 Dimensions & Levels 9

1.1.6 Notice of operation 9

1.1.7 Work program 9

1.1.8 Time Schedule 9

1.1.9 Drawings 10

1.1.10 Sub-Contracting 10

1.1.11 Compliance 10

1.1.12 Supply of Materials 10

1.1.13 Ordering Materials 10

1.1.14 Material Quality 10

1.1.15 Equipment & Facilities 11

1.1.16 Work Site Register (Site Order Book) 11

1.1.17 Area for the Contractor 11

1.1.18 Unit of measurement 11

1.2 Site Installations 11

1.2.1 Establishment of temporary infrastructure and facilities 11

1.2.2 Contractor’s site office 12

1.2.3 Labor Camps 12

1.2.4 Waste Management 12

1.2.5 Material Storage 12

1.2.6 Temporary Drainage System 12

1.2.7 Site Water Supply and Electricity 13

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1.2.8 Additional facilities to be provided 13

1.2.9 Survey Equipment 13

1.2.10 Sign Boards 13

1.2.11 Testing of Materials 14

1.3 General Contractor’s Obligations 16

1.3.1 Insurance 16

1.3.2 Safety measures and penalties 16

1.3.3 Protection of the Environment 16

1.3.4 Provision and Maintenance of labour Camps, waste management, material storage, temporary drainage system, water supply, electricity and communication facilities 17

1.3.5 As-Built Drawings 17

1.3.6 Maintenance and demobilization 17

1.4 Measurement and Payment 17

2.0 SECTION 2: EARTH WORKS 17

2.1 General 17

2.2 The Definition and Classification of materials for purpose of excavation shall be as follows: 18

2.2.1 Ordinary Soil (Normal Excavation) 18

2.2.2 Hard Soil (Intermediate Excavation) 18

2.2.3 Ordinary Rock (Intermediate Excavation) 18

2.2.4 Hard Rock (Hard Excavation) 18

2.2.5 Hard Rock ( Hard Excavation where blasting prohibited) 18

2.2.6 Marshy Soil 19

2.2.7 All Kinds of Soil 19

2.2.8 Authority for classification 19

2.3 Excavation 20

2.3.1 Setting out 20

2.3.2 Stripping and storing topsoil 20

2.3.3 Methods, tools and equipment 21

2.3.4 Rocks excavation 21

2.3.5 Marsh excavation 21

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2.3.6 Blasting 21

2.3.7 Cutting 22

2.3.8 Disposal of Excavated Material 22

2.3.9 Pumping and Bailing 22

2.3.10 Foundation Fill Material 23

2.3.11 Backfill Material 23

2.3.12 Backfilling 23

2.4 Measurements and Payments 24

3.0 SECTION 3: STRUCTURRES 25

3.1 Concrete for structures 25

3.1.1 Standards 25

3.2 Description 25

3.3 Materials 25

3.3.1 Specifications for Materials 25

3.3.2 Testing of Materials 28

3.3.3 Composition of Concrete 29

3.3.4 Control of Concrete Quality 32

3.4 Construction Methods 34

3.4.1 General 34

3.4.2 Care and Storage of Concrete Materials 34

3.4.3 Preparations before Casting 35

3.4.4 Measuring Materials 35

3.4.5 Mixing Concrete 35

3.4.6 Handling and Placing Concrete 38

3.4.7 Perforations and Embedment of Special Devices 41

3.4.8 Finishing Concrete Surfaces 41

3.4.9 Construction Joints 42

3.4.10 Curing Concrete 43

3.4.11 Removal of Scaffolding and Formwork 43

3.4.12 Repair of Concrete 43

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3.4.13 Depositing Concrete under Water 44

3.4.14 Factory Made Precast Concrete Elements 44

3.4.15 Control of Heat in Structures 45

3.4.16 Loading 45

3.4.17 Backfill to Structures 45

3.4.18 Cleaning Up 45


3.6 Formwork and Scaffolding 46

3.6.1 Scaffolding (Falsework) 46

3.6.2 Formwork 47

3.6.3 Surface Treatment for Shuttering 48

3.6.4 Camber 48

3.6.5 Approval of Scaffolding and Formwork 48

3.6.6 Special Formwork 49

3.6.7 Removal of Form Work 49

3.7 Measurements and Payment 50

3.8 Reinforcement 50

3.8.1 Description 50

3.8.2 Materials 50

3.9 Construction Methods 51

3.10 Measurement and Payments 52

4.0 SECTION 4: MISCELLANEOUS 53

4.1 Drainage for Structures 53

4.1.1 Description 53

4.1.2 Drainage Spouts 53

4.2 Measurements and Payments 54

4.3 Open surface drains 54

4.3.1 General requirements 54

4.3.2 Scope 54

4.3.3 Excavation 54

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4.5 HDPE drainage pipes 55

4.5.1 Scope 55

4.5.2 Material 55

4.5.3 Placement 55


4.7 Gabion protection works 55

4.7.1 Scope 55

4.7.2 Materials 55

Construction of Gabions 57


4.9 Elastomeric Bridge Bearings 60

4.9.1 Scope 60

4.9.2 Steel reinforced Elastomeric Bearings 60

4.9.3 Properties of Elastomer 61

4.9.4 Steel Laminates 61

4.9.5 Bond 61

4.9.6 Manufacture 61

4.9.7 Fabrication Tolerances 61

4.9.8 Marking and Certifying 62

4.9.9 Testing 62

4.9.10 Installation 63


4.11 Movement or Expansion Joints 63

4.11.1 Scope of Work 63

4.11.2 Specification for Strip Seal Expansion Joint 64


5.0 SECTION 5: DAY WORKS 67

5.1 General 67

5.2 Dayworks Labour 67

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5.3 Dayworks Materials 68

5.4 Dayworks Plant 68

LIST OF TABLES

Table 2.3-1 Grading of foundation fill material .................................................................. 23

Table 3.3-1 Grading Requirements Coarse Aggregate ................................................... 27

Table 3.3-2 Grading Requirements for Fine Aggregate .................................................. 28

Table 3.3-3 Concrete classes .............................................................................................. 30

Table 3.8-1 Removal of Form Work ................................................................................... 49

Table 4.3-1 Strip Seal Element Specifications ................................................................. 65

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1.0 SECTION 1: GENERAL AND SITE ESTABLISHMENTS

1.1 General

1.1.1 Scope of Work

The Scope of work covered by his specifications is to execute the construction of bridges on Dalbari-

Dagapela Secondary Highway (0.000 - 80.580 Km)

1.1.2 Site Acquaintance

The Contractor shall be deemed to have made himself /herself fully acquainted with the full nature of

the work, the location & character of the bridge site & means of access to the site, including any traffic

restrictions imposed. The construction site is an area within 5kms radius of the location of the bridge.

1.1.3 Specifications

The work shall be executed in accordance with the technical specifications, the drawings, the Bill of

Quantities & the instructions issued by the Client from time to time. Wherever these specifications are

found wanting in anyway, the latest edition of standard specification for Bridges as approved by the

Client shall be followed.

1.1.4 Reference to Bureau of Indian Standards Codes & Other Codes

The Standard Specifications & Codes of Practices explicitly referred to in these Specifications or other

related standard codes etc. shall be of latest editions, current at the time of tendering including all

amendments published before that date.

1.1.5 Dimensions & Levels

All dimensions & levels shown on the Drawings shall be verified by the Contractor at the site & he/she

will be held responsible for the accuracy & maintenance of all dimensions & levels. Figured

dimensions are in all cases to be accepted & no dimensions shall be scaled. Large scale details shall

take precedence over small scale drawings. In case of discrepancy the Contractor shall ask for

clarifications from the Project Manager before proceeding with the work.

1.1.6 Notice of operation

The Contractor shall not carry out important operations without the consent in writing of the Project

Manager.

1.1.7 Work program

The Contractor shall submit to the Project Manager before commencement of the work, for his

approval, a detailed program in the form of bar chart/Microsoft project etc. The submission & approval

of such program shall not relieve the Contractor of any of his duties or responsibilities under the

Contract.

1.1.8 Time Schedule

The Contractor shall follow the project master schedule & detailed activity schedule submitted after

signing the contract. The contractor may submit minor changes on schedule to the Project manager

for approval whenever necessary.

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1.1.9 Drawings

The Contractor will receive free of cost one complete set of all drawings necessary to complete the

work and the Contractor have to include in his Tender for any additional copies of drawings required

by him. One copy of the full set of drawings shall be retained at the site.

1.1.10 Sub-Contracting

Should the Contactor consider it necessary to sub-contract any part of his work, the Sub-Contractor &

the scope of the work proposed to be sub contracted has to be approved by the Project

Manager/Client. It will be the responsibility of the Contractor to ensure that the sub-contracted works

are carried out in accordance with the specifications & relevant drawings.

1.1.11 Compliance

All workmanship, materials & tests (where required) shall comply with the appropriate Indian or

American Standards as specified or approved & shall be in accordance with the drawings all to the

satisfaction of the Client/Project Manager.

1.1.12 Supply of Materials

a. The Contractor shall supply certificates of compliance with specified Indian Standards for all

materials supplied for the works. Manufacturer’s catalogues & samples of materials proposed

for procurement & to be used in the works shall be submitted to the Client for approval, before

procurement.

b. Materials procured without specific approval of the Client shall not be allowed to be used in the

works.

c. The Contractor’s quoted rate shall include but not limited to:

i. Preparation & submission of shop drawings wherever necessary, calculation sheets,

schedule of materials, & providing catalogues about, & samples of materials, & obtaining

approval from the Client.

ii. Carryout of mix design, sampling and testing of construction materials, preparation and

testing of trial mixes, preparation and testing of concrete test cubes, and obtaining

approval from the Client.

iii. Transporting to the Site, including loading & unloading.

iv. Providing certificates of compliance with required relevant standards, as specified.

v. Storing & protection of the materials at the Site.

1.1.13 Ordering Materials

The Contractor is entirely responsible for assessing the quantities of materials to be ordered for use in

the works.

1.1.14 Material Quality

The Contractor should note that the qualities of all materials used shall be scrutinized, monitored &

checked by the Client. All materials used have to fulfill the requirements & specifications given in the

drawings & in the relevant code of practice. If the Contractor is asked to supply certificate of origin of

the supplied & used materials, he has to do so within a reasonable timeframe fixed by the Project

Manager.

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1.1.15 Equipment & Facilities

The Contractor shall provide & operate equipment & facilities to load, offload, shift, move, transport,

stack & place all types of steel parts & materials at the bridge site as well as at the Contractor’s yard.

The Contractor shall also provide all lifting equipment & facilities to lift, shift, stack, load, unload &

handle all type of steel parts & materials at the bridge site as well as at the Contractor’s yard.

1.1.16 Work Site Register (Site Order Book)

The Contractor shall keep a Work Site Register (Site Order Book) at the Site in which all the remarks,

instructions, decisions of the Client & the essential details of the work shall be recorded. The

Contractor shall keep the records of all daily information of the works in this register as required by the

Client. It shall be readily available in the office for inspection.

1.1.17 Area for the Contractor

i. The Contractor shall be allocated an area for his equipment, materials & site offices in the

vicinity of the bridge site.

ii. The Contractor shall maintain a properly furnished office, which will include but not necessarily

limited to lock up drawers for construction drawings, filing cabinets, large sized soft board

panels etc., with toilet facility in the allocated area at the site for his own use as well as for use

of the Client & his representatives. These shall be provided by the Contractor at no extra cost.

1.1.18 Unit of measurement

The following units of measurement & abbreviations shall be used.

Unit Abbreviation

Millimeter Mm

Meter M

Square millimeter mm2

Square meter Sq.m

Hectare Ha

Cubic metre Cu.m

Kilogram Kg

Tonne Ton

Sum Sum

Number no.

Hour Hr

Week wk (7 days)

Pieces Pcs

1.2 Site Installations

1.2.1 Establishment of temporary infrastructure and facilities

As a part of the site installation, the contractor shall build and maintain all temporary infrastructures

such as contractor’s office, stores, workshops, Contractor's yard, labor camp, access roads etc. for

smooth implementation of the works.

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The following facilities, but not limited to, shall be installed/built and maintained by the contractor as a

part of the site installation:-

1.2.2 Contractor’s site office

The contractor shall build and maintain a site office with sanitary facilities during the project duration.

The site office shall have a minimum plan area of 50m2 and shall have at least concrete flooring,

bamboo mat or ekra wall and CGI roof. The contractor’s site office shall have minimum following

facilities:-

i. Desk top computer set with sufficient capacity to run standard engineering softwares such as

AUTO CAD, LISCAD etc. - 1 no.

ii. A3 printer - 1 no.

iii. Photocopy Machine - 1 no.

iv. Scanner - 1 no.

v. Internet connection (subject to availability of the facility at the project site)

vi. Tables and chairs sufficient to conduct site meetings between the contractor and the

representatives of the Client

1.2.3 Labor Camps

Labor camps with sufficient and maintained sanitary facilities, sufficient & safe drinking water and

sufficient supply of electric power have to be made available at all times during the project duration.

The labor camps shall at least have concrete flooring, bamboo mat wall and CGI roof. The size and

number of such camps shall be approved by the Project Manager based on the labor strength

requirement after contractor submits the master work plan

1.2.4 Waste Management

A proper waste management facility and system have to be put in place to maintain general

cleanliness of the site and upkeep hygiene of the personnel and laborers working at the bridge site.

The proposed facilities has to be approved by the Project Manager.

1.2.5 Material Storage

Construction materials have to be stored well under sheds to avoid quality drops and loss.

Minimum following facilities have to be erected at the bridge site as a part of site installation for

material storage:-

i. Cement store – min. plan area 50m2, CC flooring, tin wall & roof (water tight and limited air

circulation) - 1 no.

ii. General store – min. plan area 25m2, CC flooring, bamboo mat/ekra wall and tin roof

- 1 no.

1.2.6 Temporary Drainage System

The Contractor shall build a temporary drainage system at the site to drain out waste water. The

layout and design of the drains have to be approved by the Project Manager.

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1.2.7 Site Water Supply and Electricity

The Contractor shall make his own connections for water and electric supply and pay for them.

The water supplied must be potable and must be free from salts, oils, acids, arsenic and other

substances harmful to health. The water shall be tested to confirm its portability

If electricity is not available at the bridge site, the Contractor shall install generators of sufficient

number and capacity to power all the facilities at the bridge site such as the Project Manager’s Office,

Contractor’s office, laboratory, labor camps, stores etc. If the Contractor intends to use electrically

operated construction equipment and machinery, matching number and capacity of generators have

to be installed at the bridge site.

1.2.8 Additional facilities to be provided

As a part of the site installation, the contractor shall provide/build/install following additional facilities:-

1.2.9 Survey Equipment

The Contractor will be required to provide survey equipment for the use of the Contractor and Project

Manager and his staff. The equipment and all its accessories shall be available at all times at the

bridge site during the contract period and shall be maintained in good working order. For higher

accuracy and better ease of use, the equipment shall be Total Station or equivalent. The contractor

shall depute appropriately qualified and trained personnel to operate the survey equipment at all times

during the contract period.

The survey equipment and its accessories (legs, reflectors and stands, rechargeable batteries and

charger etc.) shall be from any reputable manufacturer. The range, accuracy, least count etc. of the

equipment has to be approved by the Project Manager.

1.2.10 Sign Boards

The Contractor shall provide identification sign boards and maintain them in good condition. All

information on the signboards will be written in English and Dzongkha. The signboards will be

positioned as directed by the Project Manager.

Each sign shall show:

the name of the Project

the name of the Employer

name of the Contractor

Contract start and completion dates

Contract amount

Any other details as required by the Project Manager

Project Signboards shall have steel pipe posts of diameter from 75mm to 100mm with 3mm thick steel

plates. The steel pipe legs shall be embedded in the ground. The design of the signpost and the

information content on it shall be approved by the Project Manager.

The contractor shall install at least one sign board at the bridge site, the location of which shall be

approved by the Project Manager.

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The Contractor shall remove the sign boards on completion of the Works or when instructed by the

Project Manager

1.2.11 Testing of Materials

1.2.11.1 Contractor’s Site Laboratory

The Contractor shall provide and maintain a Site Laboratory in a semi-permanent building of about

25m2 plinth area with concrete floor, bamboo mat wall & CGI roof for the use of the Contractor and the

Project Manager.

The laboratory shall have furniture, testing equipment and consumable stocks necessary to carry out

the tests listed below:-

1. Moisture Content

2. Particle Size Distribution

3. Standard Compaction

4. Flakiness Index

5. Fineness Modulus

6. Aggregate Crushing Value

7. Slump Test

8. Concrete Crushing Strength

The Contractor would be required to mobilize, but not limited to, the following equipment for quality

assurance tests both at site and at the site laboratory as a part of site installation:

1. Moisture can

2. Weighing balance (accuracy 0.01 gm)

3. 1000 ml glass cylinder with rubber bung

4. Graduated measuring cylinder

5. Hydrometer

6. Thermometer

7. Sample tray

8. Straight edge knife

9. Scoop

10. Mixing trowel

11. Sand pouring cylinder with lid

12. Metal tray

13. Flakiness index gauge

14. Sieve set

15. Slump cone

16. Scale

17. Concrete crushing machine

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18. Concrete cube mould

19. Tamping rod

20. Hand gloves & filter papers

21. Concrete thermometers

The Contractor shall provide a sufficient number of cube moulds to meet the testing frequency

requirements for the concrete pour program for all the sites under the Contract. A reasonable number

of spare moulds should also be available for any ‘ad hoc’ testing that may be required.

The laboratory shall be housed inside a proper shelter. The layout, size and location of the site

laboratory have to be approved by the Project Manager.

The Contractor shall maintain the laboratory, furniture, fittings and testing equipment for the duration

of the Contract and replace any part or item that is irreparably damaged or lost. The Contractor shall

pay all expenses in respect of water, electricity and other consumables necessary for the running of

the laboratory and shall arrange for the laboratory to be regularly cleaned.

The Contractor shall not be permitted to commence permanent works requiring on-site testing till the

Site laboratory is complete in all respects, unless temporary testing procedures proposed by the

Contractor have been approved by the Project Manager.

At the end of the Contract, all materials recovered from dismantling the laboratory, together with all

furniture, fittings and testing equipment will remain the property of the Contractor.

1.2.11.2 Materials Testing by Independent Laboratories

In addition to the above mentioned tests the Contractor shall arrange for the following tests to be

carried out at off-site testing facilities as and when instructed by the Project Manager:

1. Tests on reinforcing steel

2. Tests on cement – fineness, setting time and strength

3. Aggregate crushing value

4. Any other tests as may be decided by the Project Manager

The Contractor shall be responsible for arranging off-Site laboratory tests, and all other tests indicated

as the responsibility of the Contractor in different Sections of the Specifications. These tests shall be

performed by off-site standard testing laboratories proposed by the contractor and as approved by the

Project Manager. All the expenses for such tests shall be borne by the contractor. The Contractor

shall be responsible for all attendance of staff from these approved testing laboratories, including if

necessary the provision of transport for personnel, equipment and test specimens.

1.2.11.3 Staff for Materials Testing

The laboratory engineers and technicians shall be provided by the contractor to carry out sampling

and testing of materials in accordance with Specifications Sections, 1.2.11.1, and

1.2.11.4 Sampling and Testing

For Concrete Mixes 1 set of tests per 100 m3

of aggregate for shape, grading, ACV / 10% Fines

should be carried out.

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The Contractor shall maintain complete records of test results, which may be inspected by the Project

Manager at any time. All test results shall be recorded on standard forms approved by the Project

Manager and shall be signed by the Contractor’s engineer or technician in charge of the laboratory.

Completed forms shall clearly show the locations of samples, sampling dates and testing dates.

Samples shall be numbered serially at the time of sampling. A copy of all test results should be

submitted to the Project Manager immediately after completion of the test.

The Project Manager will be informed prior to any sampling or testing carried out in the laboratory and

will have the right to use the facilities and equipment to make his own tests. The Contractor shall have

the right to witness any sampling or testing carried out by the Project Manager. On completion of the

Contract the original copies of all test results shall be handed over to the Employer, via the Project

Manager.

1.3 General Contractor’s Obligations

1.3.1 Insurance

The contractor shall obtain all risk insurance for the work, plant, equipment, personnel and labor. The

modalities for the insurance shall be as per the stipulations under Clause 13 of General Conditions of

Contract (GCC).

1.3.2 Safety measures and penalties

The regulations and guidelines for Work Place Safety issued by Ministry of Labor and Human

Resources, RGoB shall be complied with at all times. The workers and the personnel shall have safe

and secure working conditions at the construction site at all times and there shall be no compromise

on the work place safety. The workers shall wear safety gears – helmets, boots, belts, goggles, hand

gloves, welding masks etc. as may be appropriate, at the work site at all times.

The Contractor shall issue the required protective clothing and safety equipment to all his employees

and provide the first aid boxes within one month of the commencement of the Contract. He is

responsible for ensuring that all his employees make appropriate use of the items and maintain them

in good order. The Contractor shall replace damaged, worn-out, exhausted or out of date items as

necessary.

The Contractor shall build temporary scaffold, temporary stairs, working platforms, fall-down-stoppers

and such other measures to allow safe and proper execution and check of the construction works.

Anybody entering the worksite shall wear safety helmets at all times. If scaffold, working platforms etc.

are not possible or not required, the personnel and the workers have to wear safety belts. The quality

of the safety belts has to be approved by the Project Manager.

1.3.3 Protection of the Environment

The Contractor has to allow for complying with his obligations for safety, security and protection of the

environment described in the Contract Documents included in the related Sub-Clauses of the

Conditions of Contract. The Contractor is not allowed to dispose or dump any kind of waste materials

into the river. The contractor has to, at the end of the project, remove and clean the waterway of all

the temporary constructions that it has built for the purpose of securing temporary supports or

restraints for the permanent structures, installations for safety measures etc. and which do not

ultimately form the part of the permanent structure.

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1.3.4 Provision and Maintenance of labour Camps, waste management, material

storage, temporary drainage system, water supply, electricity and communication

facilities

The Contractor shall provide labour camps, waste management system, material storage facility,

temporary drainage system, water supply, electricity and communication facilities as outlined in sub-

clause 1.2

1.3.5 As-Built Drawings

The Contractor shall furnish sets of as-built Drawings of the Works to the Project Manager, showing

the permanent works as actually constructed, within one month of completion of the Works. Included

in the sets of as-built Drawings will be revisions of Tender Drawings and Drawings supplied to the

Contractor during the Contract as well as revisions of drawings supplied by the Contractor during the

Contract. The As-built drawings submitted by the Contractor will be subject to the approval of the

Project Manager.

1.3.6 Maintenance and demobilization

The Contractor shall properly maintain all the infrastructures built at the site such as office, stores,

yards, labor camps etc. till the end of the Project. At the end of the Project, the Contractor has to

remove and demobilize all the temporary infrastructures that it has built and restore the bridge site to

its original condition and shape. The dismantling and demobilization shall be completed within the

stipulated contract duration.

1.4 Measurement and Payment

The site installation shall include cost of all temporary infrastructure facilities, tools and plants, safety

gears etc. as described under Section 1.2. of this specification. The quantity, size and other

specifications of various facilities mentioned here are the minimum requirements. While the minimum

requirements have to be fulfilled to be eligible for payment under site installation, the contractor may

actually required to provide more than what is specified here for smooth implementation of the project.

If the Project Manager finds the site facilities provided by the contractor as per the minimum

requirement in this specification inadequate for smooth or proper implementation of the works, he will

have the right to demand the contractor to install/provide addition facilities/installations for which

contractor cannot claim additional payment.

2.0 SECTION 2: EARTH WORKS

2.1 General

This work shall consist of excavation, removal and satisfactory disposal of all materials necessary for

the construction in accordance with requirements of these specifications and the lines, grades and

cross-sections shown in the drawings or as indicated by the Project Manager.

It shall also include backfilling of the excavated foundations not occupied by the structures and

compacted filling with suitable materials of the abutments, return walls, wing walls and retaining walls.

DING & ROAD WORKS 2009

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2.2 The Definition and Classification of materials for purpose of excavation shall be

as follows:

2.2.1 Ordinary Soil (Normal Excavation)

Generally any soil which yields to the ordinary application of pick and shovel, rake or any

other ordinary digging equipment; such as vegetable or organic soil, turf gravel, sand, silt loam,

clay, peat etc.

2.2.2 Hard Soil (Intermediate Excavation)

Generally any soil which requires close application of picks or jumpers or scarifiers to loosen;

such as stiff clay, gravel, cobble stone, water bound macadam and soling of roads

2.2.3 Ordinary Rock (Intermediate Excavation)

Generally any rock which can be excavated by splitting with crow bars or picks and does not

require blasting, wedging or similar means of excavation such as lime stone, sand stone, hard

laterite, hard conglomerate and un-reinforced cement concrete below ground level. If required

light blasting may be resorted to, for loosening the materials but this will not in any way entitle the

material to be classified as “Hard Rock”

2.2.4 Hard Rock (Hard Excavation)

Generally any rock or boulder for the excavation of which blasting is required such as quartzite,

granite, basalt, reinforced cement concrete ( reinforcement to be cut through but not separated

from concrete) below ground level and the like.

2.2.5 Hard Rock ( Hard Excavation where blasting prohibited)

Hard rock requiring blasting as described above but where the blasting is prohibited for any

reason and excavation has to be carried out by chiseling, wedging or any other agreed method.

The PETTIFER point load index graph as per BS:5930 shall be used to classify the material type (soil

or rock) in case of any misunderstanding and or disputes between the contractor and the Project

Manager in the classification of soil.

The classification requires testing of the rock lumps of 5 representative samples in the laboratory

using point load test apparatus to obtain point load Index (IC50). The discontinuity spacing index (Ii)

shall be noted jointly by the contractor and the Project Manager. Using these two parameters the ‘soil’

or ‘rock’ type shall be classified. All easy to moderately hard digging shall be classified as soil and

easy ripping to material requiring use of rock breaker or controlled blasting shall be classified as

‘rock’.

Page 19 of 69


Figure 2.1 : PETTIFER point load Index graph

2.2.6 Marshy Soil

This shall include soils like soft clays and peat excavated below the original ground level of

marshes and swamps and soils excavated from other areas requiring continuous pumping or

bailing out of water.

2.2.7 All Kinds of Soil

Generally any strata, such as sand, gravel, loam, clay, mud, black cotton soil, moorum,

shingle, river or nallah bed boulders, soiling of roads, paths etc. and hard core macadam

surface of any description (water bound, grouted tarmac etc.), lime concrete, mud concrete

and their mixtures which for excavation yields to the application of picks, shovels, jumpers,

scarifiers, ripper and other manual digging implements.

2.2.8 Authority for classification

Project Manager shall decide the classification of excavation and his decision shall be final and

binding on the Contractor. Merely the use of explosives in excavation will not be considered

Page 20 of 69


as a reason for higher classification unless blasting is clearly necessary in the opinion of the

Project Manager.

2.3 Excavation

All excavations shall be carried out in conformity with the directions laid herein-under and

in a manner approved by the Project Manager. The works shall be so done that the suitable

materials available from excavation are satisfactorily utilized as decided upon beforehand.

While planning of excavations, the Contractor shall take all adequate precautions against soil

erosion, water pollution etc. and take appropriate drainage measures to keep the sites free of

water.

The excavations shall conform to the lines, grades, side slopes and levels shown on the

drawings or as directed by the Project Manager. The Contractor shall not excavate outside

the limits of excavation. Subject to the permitted tolerances, any excess depth/ width

excavated beyond the specified levels/dimensions on the drawings shall be made good at the

cost of the Contractor with the suitable material of characteristics similar to that removed

and compacted.

All debris and loose materials on the slopes of cutting shall be removed. No backfilling shall be

allowed to obtain required slopes excepting that when boulders or soft materials are encountered

in the cut slopes, these shall be excavated to approved depth on instructions of the Project

Manager and the resulting cavities filled with suitable materials and thoroughly compacted in

an approved manner.

After excavation, the sides of the excavated areas shall be trimmed and the area contoured to

minimize erosion and ponding, allowed for natural drainage to take place. If trees were removed,

new trees shall be planted, as directed by the Project Manager. The cost of planting new trees

shall be deemed to be incidental to the work.

2.3.1 Setting out

After the site has been cleared, the limits of excavation shall be set out true to lines, curves,

slopes, grades and sections as shown on the drawings or as directed by the Project Manager. The

Contractor shall provide all labour, survey instruments and materials such as strings, pegs, nails,

bamboos, stones, lime, mortar, concrete, etc., required in connection with the setting out of

works and the establishments of bench marks. The Contractor shall be responsible for the

maintenance of the benchmarks and other marks and stakes as long as in the opinion of the

Project Manager, they are required for the work.

The ground levels shall be taken at 5m to 15m intervals in uniformly sloping ground and at closer

intervals where local mounds, pits or undulations are met with. The ground levels shall be

recorded in field books and plotted on plans. Plans shall be drawn to a suitable scale and North

direction and position of benchmark shall be shown on the plans. The contractor and the

Project Manager shall sign the plan before the earthwork is started. The contractor at his own

cost shall supply the labour required for taking levels.

2.3.2 Stripping and storing topsoil

When so directed by the Project Manager, the topsoil existing over the sites of excavation

shall be stripped to specify depths and stockpiled at designated locations for re-use in

Page 21 of 69


covering embankment slopes, cut slopes, and other disturbed areas where re -vegetation is

desired. Prior to stripping the topsoil, all trees, shrubs etc. shall be removed along with their roots,

with the approval of the Project Manager.

2.3.3 Methods, tools and equipment

Only such methods, tools and equipment as approved by the Project Manager shall be

adopted/used in the work. If so desired by the Project Manager, the Contractor shall

demonstrate the efficacy of the type of equipment to be used before the commencement of the work.

Methods, tools and equipment to be adopted for the work shall be such which will not affect the

property to be preserved

2.3.4 Rocks excavation

Rocks, when encountered in the road excavation, shall be removed up to the formation level or

as otherwise indicated on the drawings. Where, however, unstable shale or other unsuitable

materials are encountered at the formation level, these shall be excavated to the extent of 500

mm below the formation level or as otherwise specified. In all cases, the excavation operations

shall be so carried out that at no point on cut formation the rock protrudes above the specified

levels. rocks and large boulders which are likely to cause differential settlement and also local

drainage problems should be removed to the extent of 500 mm below the formation level in full

formation width including drains and cut through the side drains.

Slopes in rock cutting shall be uniform lines corresponding to slope lines shown on the

drawings or as directed by the Project Manager. Notwithstanding the foregoing, all loose pieces

of rock on excavated slope surface, which move when pierced by a crowbar, shall be removed.

Where blasting is to be resorted to, the same shall be carried out as per the RGOB blasting

manual and all precautions indicated therein observed.

2.3.5 Marsh excavation

The excavation of soils from marshes/swamps shall be carried out as per the programme

approved by the Project Manager. Excavation of marshes shall begin at one end and proceed in

one direction across the entire marsh immediately ahead of back filling. The method and

sequence of excavating and back filling shall be such as to ensure, to the extent practicable, the

complete removal or displacement of all muck from within the lateral limits called for on the

drawings or as staked by the Project Manager, and to the bottom of the marsh, firm support

or levels indicated.

2.3.6 Blasting

The contractor shall obtain a licence from the competent authority for obtaining and storing the

explosives. The contractor shall procure the explosives, fuses, detonators etc. from the Government

or as per the provision in terms and condition of the contract. The Project Manager or his

representative shall have the right to check the contractor's store and accounts of explosives.

The contractor shall provide facilities for this.

All blasting work shall only be done under careful supervision of trained personnel and the

contractor shall take all precautions as per rules for blasting operations.

Page 22 of 69


The contractor shall be responsible for any damage arising out of accident to the workmen,

public or property due to storage, transportation and use of explosive during blasting

operations.

2.3.7 Cutting

In firm soil, the sides of the trench shall be kept vertical up to a depth of 2m from the bottom. For a

greater depth, the excavation profiles shall be widened by allowing steps of 500mm on either side

after every 2m from the bottom. Alternatively the excavation can be done so as to give slopes of

1:4.

Where the soil is soft, loose or slushy, the width of steps shall be suitably increased or side

sloped or the soil shored up as directed by Project Manager. It shall be the responsibility of the

contractor to take complete instructions in writing from Project Manager regarding the

stepping, sloping or shoring to be done for excavation deeper than 2 metres.

The bed of excavation shall be made to the correct level or slope and consolidated by watering

and ramming. Soft/defective spots shall be dug out and filled with levelling concrete as directed

by the Project Manager. The excess depth shall be made good by the contractor at his own cost

with the concrete of the same mix as levelling concrete.

Where hard rock is met with and blasting operations are considered necessary, the contractor

shall obtain the approval of the Project Manager. For an ordinary rock, in general, the

blasting operation is not adopted but if the contractor wishes to resort to blasting, he can do so,

with the permission of the Project Manager but nothing extra shall be paid for this blasting

2.3.8 Disposal of Excavated Material

Excavated material classified as suitable by the Project Manager shall generally be utilized as backfill

or embankment fill. Surplus suitable material shall be stockpiled at the Site. Excavated suitable

material for use as backfill shall be deposited by the Contractor in spoil heaps at points convenient for

re-handling of the material during the backfilling operation and approved by the Project Manager.

Excavated material classified as unsuitable as backfill by the Project Manager shall be carried to

waste.

Excavated material shall be deposited in such places and in such a manner as not to cause damage

to roads, services or property either within or outside the right-of-way and so as to cause no

impediment to the drainage of the site or surrounding area. The location of spoil heaps shall be

subject to the approval of the Project Manager who may require that the reference lines and the

traverse lines of any part of the structure be kept free of obstruction.

2.3.9 Pumping and Bailing

Pumping and bailing from the interior of any foundation enclosure shall be done in such a manner as

to preclude the possibility of the movement of water through or alongside any concrete being placed.

No pumping or bailing will be permitted during the placing of concrete and for a period of at least 24

hours thereafter unless it is done from a suitable pump separated from the concrete work by a

watertight wall or from well points.

Excavations shall be as dry as possible prior to and during placing concrete. Placing concrete under

water will only be permitted if indicated on the Drawings or approved by the Project Manager.

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2.3.10 Foundation Fill Material

Material for foundation fill shall be a natural or artificial mixture of sand or other mineral aggregate,

free from vegetable matter, soft particles and excess clay and shall consist of suitably graded sand to

one of the grading envelopes A to C of Table 2.3, gravel or stone as shown on the Drawings or as

required by the Project Manager, or concrete. Concrete for foundation fill shall conform to the general

requirements of Section 3.1. Concrete to be placed under water shall conform to the requirements of

Section 3.4.13. Concrete used as foundation fill in dry excavation shall be M15.

Table 2.3 Grading of foundation fill material

A B C D E

Nominal

fineness

modulus

Not less

than 2.8

1.5-2.8 1.0-1.5 0.8-1.0 0.5-0.8

Sieve size

(mm)

% passing by weight

10 100 100 100 100 100

5.0 90-95 95-100 100 100 100

2.4 70-90 90-100 100 100 100

1.2 45-70 70-95 95-100 100 100

0.6 25-45 40-80 85-100 95-100 100

0.3 10-20 10-50 50-80 70-90 80-95

0.15 0-2 0-20 5-25 15-40 30-60

Grading outside the above limits may in certain circumstances be approved by the Project Manager.

Such permission shall be in writing.

2.3.11 Backfill Material

The excavated materials shall be used for backfilling if found suitable and approved by the Project

Manager. The source (borrow pit) and type of fill material have to be approved by the Project

Manager.

The earth shall be free from all roots, grass and rubbish. All lumps and clods exceeding 80mm in any

direction shall be broken and each layer shall be consolidated by ramming and rolling, etc. Watering

shall be done, if so stipulated. The top surface of the finally finished area shall be neatly dressed.

The finished formation levels, in case of filling shall be kept higher than the required levels, by making

an allowance of 10% of depth of filling for future settlement in case of ordinary consolidated fills, and

5% in case where consolidation is done by heavy mechanical machinery under optimum moisture

conditions.

2.3.12 Backfilling

All spaces excavated under these Specifications and not occupied by the permanent structure shall

be backfilled. However, the finished level of the back fill shall be as per the lines and levels of the

finished profile of the slope shown in the design drawings. Backfilled material shall fully comply with

this Specification and adequate provision shall be made for drainage. No backfilling shall commence

until permission has been given by the Project Manager.

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Backfilling shall be well compacted and shall be done in layers, not exceeding 200mm in each layer.

Each layer shall be watered, rammed and consolidated before the succeeding one is laid.

Special care shall be taken to prevent any unduly high pressure against the structures. In placing

backfill and embankment, the material shall be placed insofar as possible to approximately the same

height on both sides of the structure at the same time. If conditions require backfilling appreciably

higher on one side, the additional material on the higher side shall not be placed until permission is

given by the Project Manager that the structure has enough strength to withstand any pressure

created.

2.4 Measurements and Payments

The volume of excavation shall be measured in cubic meters of excavated undisturbed material.

The quantity of excavation for structures to be measured for payment shall include excavation for all

structures. The measured volume shall be the excavation plan outline, bounded on the bottom by the

plane of the underside of the blinding concrete under the reinforced concrete footing and on the top by

the surface of the existing ground and on the sides by vertical planes of the footings and the volume

so measured shall be term as “Solid Volume”.

Additional excavations for slope cutting, working space and for other purposes of construction ease

and convenience shall not be paid extra. The cost for such additional excavation works is deemed to

be included in the unit rates under the payable items and quantities of the excavation works. The

removal of slides, cave-ins, silting or filling shall also neither be measured nor paid for.

The soil/rock excavation for construction/widening of approach roads to the bridge however shall be

measured as actual volume of excavation as per the drawings or as directed by the Project Manager

as per the actual requirement of the site. The contractor has to do a detail survey of the area to be

excavated as per direction of the Project Manager prior to and after the excavation to arrive at the

actual volume of excavation. The measured volume shall be in-situ volume and no allowance shall be

allowed for bulking and other forms of volume change.

The measured volume for backfilling and filling behind the abutment/return walls etc. shall be the

backfilling plan outline bounded at the bottom by the plane of the underside of the blinding concrete

under the reinforced concrete footing and on the top by the surface of the finished ground and on the

sides by vertical planes of the footings minus the volume occupied by the permanent structure.

However the areas around the foundations excavated by the contractor for creating working space,

stabilizing excavation slope etc. shall be backfilled to required degree of compaction as per this

specification at the contractor’s own cost.

The length, breadth and depth/height shall be measured correct to 10mm. In case the measurements

are taken with staff and level, the level shall be recorded correct to 5mm and depth of cutting and

heights of filling calculated correct to 5mm. The cubical contents shall be worked out to the nearest

two places of decimal in cubic metres.

The rates shall cover the cost for carrying out all the required operations including cost of labour,

materials, equipment hired/owned, tools and plants, and incidentals necessary to complete the work.

In case of rock, the rate shall also include the cost of all operations of blasting with explosive and

accessories as mentioned above. The excavation of Bridge foundation shall be paid in cum as per

BoQ item No 14.A.2

Page 25 of 69


3.0 SECTION 3: STRUCTURRES

3.1 Concrete for structures

3.1.1 Standards

The concrete materials, production, methods, testing & admixtures shall conform to the latest

revisions of the following Indian Standards or, where not covered by these standards, to the

equivalent International Standards:

IS: 8112 43 grade Ordinary Portland Cement.

IS: 12269 53 grade Ordinary Portland Cement.

IS: 383 Coarse & fine aggregates from natural sources for aggregates.

IS: 456 Code of practice for plain & reinforced concrete.

IS: 457 Code of practice for general construction of plain & reinforced concrete for dams &

other massive structures.

IS: 516 Method of test for strength of concrete.

IS: 1199 Methods of sampling & analysis of concrete.

IS: 1489 Portland Pozzolana cement.

IS: 2386 Methods of test for aggregates for concrete.

IS: 2505 Concrete vibrators – immersion type – general.

IS: 2506 General requirements for screed board concrete vibrators.

IS: 4082 Stacking & storage of construction materials & components at site– recommendations.

IS: 7861 Code of practice for extreme weather concreting.

IS: 9103 Admixtures for concrete.

IS: 10262 Recommended guidelines for concrete mix design.

IRC: 112 Code o Practice for Concrete Road Bridges

In cases of conflict between or among the above standards & the specifications given herein, the

decision of the Client shall prevail.

3.2 Description

This work shall consist of the construction of all or portions of concrete structures, of the required

grades and types, with or without reinforcement and with or without admixture, in accordance with

these Specifications and to the lines, levels, grades and dimensions shown on the Drawings and as

required by the Project Manager.

The cement concrete shall consist of a mixture of cement, water and coarse and fine aggregate with

or without admixture.

3.3 Materials

3.3.1 Specifications for Materials

A) Cement

Cement shall conform to the requirements of Indian Standard as mentioned in Article 3.1.1 of this

specification unless other types are indicated on the Drawings or specified by the Project Manager.

One of the types of the cements, specified below shall be used.

a) Ordinary Portland cement conforming to IS: 269

b) Portland blast furnace slag cement conforming to IS: 455

Page 26 of 69


e) Portland pozzolana cement conforming to IS: 1489

Bagged or bulk cement which has partially set or which contains lumps of caked cement shall be

rejected. The use of cement reclaimed from discarded or used bags shall not be permitted.

B) Water

Water used for mixing mortars and concrete shall be clean and reasonably free from injurious

quantities of deleterious materials such as oils, acids, alkalis, salts and vegetable growth. Generally

potable water shall be used. Where water can be shown to contain any sugar or an excess of acid,

alkali or salt, the Project Manager may refuse to permit its use. As a guide, the following

concentrations may be taken to represent the maximum permissible limits of deleterious materials in

water.

(a) Limits of acidity: - To neutralize 200 ml sample of water, it should not require more than 2 ml of 0.1

N caustic soda solutions.

(b) Limits of Alkalinity: - To neutralize 200 ml sample of water it should not require more than 0.1 ml of

0.1 N hydrochloric acid.

(c) Percentage of solids should not exceed: -

Organic 200 ppm (0.02%)

Inorganic 3000 ppm (0.30%)

Sulphates 500 ppm (0.05%)

Alkali chlorides 1000 ppm (0.1%)

Water found satisfactory for mixing is suitable for curing concrete. However, the water used for curing

should not produce any objectionable stain or deposit on the concrete surface.

The use of river water will be subject to the approval of the Project Manager. Such approvals may be

withdrawn from time to time depending on the condition of the river.

C) Admixtures

Admixtures or any other additions shall not be used except with the written approval of the Project

Manager.

Admixtures, if specified or permitted, shall fully conform to the requirements of Indian Standard IS:

9103

D) Coarse Aggregate

Coarse aggregate for all types of concrete with the exception of blinding concrete shall consist of hard

durable crushed or broken rock and generally conform to the requirements of Indian Standard IS: 383

(or AASHTO Standard Specification M 80 or ASTM C33 / C33M – 08). Coarse aggregate shall be

clean, free from dust and other deleterious material.

The amounts of deleterious substances shall not exceed the following limits:

1) Soft fragments; 2% by mass

2) Clay lumps; 0.25% by mass

Page 27 of 69


3) Material Passing the 0.075 mm sieve; 0.50% by mass if clay, 1.50% by mass if fractures dust

In addition, coarse aggregates shall comply with the following:

1) Thin or elongated pieces; Flakiness Index less than 30

2) The aggregate crushing value shall be less than 30% and the ten percent fines value shall be

greater than 150 kN.

The grading of coarse aggregate of shall conform to Table 3.3below.

Table 3.3 Grading Requirements Coarse Aggregate

In heavily reinforced structures with difficult casting conditions smaller size aggregates may be used if


E) Fine Aggregate

Fine aggregate shall consist of natural sand and fine aggregates. Fine aggregates from different

sources of supply shall not be mixed or stored in the same pile.

The amounts of deleterious substance when tested shall not exceed the following limits:

1) Friable Particles; 0.5% by mass

2) Coal and Lignite; 0.5% by mass

3) Material passing the 0.075 mm sieve; 3.0% by mass

4) Any other deleterious materials shall not cause a strength reduction of the concrete of more

than 5% in relation to the strength of concrete free of the concerned deleterious material.

The grading shall normally be in accordance with Table 3.3. In the event that it is not possible to

obtain regular supplies of sand conforming to this grading, the Project Manager may approve the

adoption of an alternate grading conforming to the requirements of the mix design. However, any

additional cost results from changes in aggregate proportions or additional cement contents required

Page 28 of 69


to achieve the specified strengths, when using these alternative grading, shall be borne by the

Contractor and shall not be reimbursed.

Table 3.3 Grading Requirements for Fine Aggregate

Grading Requirements for Fine Aggregate

Sieve Size (mm) % Passing by Weight

10.0 100

5.0 95-100

1.2 45-80

0.30 10-30

0.15 2-10

3.3.2 Testing of Materials

A) Cement

Cement shall be in accordance with Indian Standard. The Contractor must provide the Project

Manager with manufacturer’s certificates indicating compliance.

Cement shall be sampled and tested for fineness, setting time and strength in accordance with IS:

615 at the Contractor’s expense. The Contractor shall notify the Project Manager of delivery dates so

that there will be sufficient time for sampling the cement, either at the mill or upon delivery. If this is

not done, the Contractor may be required to re-handle the cement in the store for the purpose of

obtaining the required samples.

Sampling shall normally be instructed by the Project Manager for every batch of cement prior to this

cement being incorporated in the Works.

B) Water

The water proposed by the Contractor to be used in mixing or curing concrete shall be tested by

methods described in Indian Standard or AASHTO Test Method T 26 [or ASTM C1602 / C1602M –

06].

In sampling water for testing, care shall be taken that the containers are clean and that samples are

representative.

When comparative tests are made with a water of known satisfactory quality, any indication of

unsoundness, marked change in time of setting, or a reduction of more than 10 percent in mortar

strength, shall be sufficient cause for rejection of the water under test.

The water shall be tested at a recognized laboratory approved by the Project manager. The test result

shall be signed by the laboratory. The water shall be tested before commencement of work or if the

source is changed or at any time required by the Project Manager. All testing shall be carried out at

the Contractor’s expense.

C) Admixtures

Page 29 of 69


Chemical admixtures are not to be used until permitted by the Project manager. In case their use is

permitted, the type, amount and method of use of any admixtures proposed by the Contractor shall be

submitted to the Project Manager for approval. The minimum cement specified shall not be reduced

on account of the use of the admixtures.

The contractor shall provide the following information concerning each admixture to the Project

Manager:

a. Normal chemical dosage and detrimental effects if any of under dosage and over dosage.

b. The chemical names of the main ingredients in the admixtures.

c. The chloride content, if any, expressed as a percentage by weight of admixture.

d. Whether or not the admixture leads to the entrainment of air when used in the manufacturer’s

recommended dosage.

e. Where two or more admixtures are proposed to be used in any one mix, the manufacturer’s

written confirmation of their compatibility.

3. In reinforced concrete, the chloride content of any admixture used shall not exceed 2 percent

by weight of the admixtures as determined in accordance with IS: 6925 and the total chloride

and sulphate contents in concrete mix shall not exceed 1.15 and 4.0 percent respectively by

weight of cement.

The admixtures when used shall conform to IS: 9103. The suitability of all admixtures shall be verified

by trial mixes.

The addition of calcium chloride to concrete containing embedded metal will not be permitted under

any circumstances.

Retarding admixtures when used shall be based on ligno-sulphonates with due consideration to

clause 5.2 and 5.3 of IS: 7861

D) Aggregates

1) Selection and Approval

From the aggregate materials proposed by the Contractor, samples shall be selected according to

Standard Testing Procedure and in the presence of the Project Manager. The samples shall be tested

at the site laboratory or at an approved testing laboratory for conformance with Section 3.3.1 of these

Specifications.

2) Quality Control

The quality control of the aggregate shall be as directed by Project Manager. Grading shall be

checked at regular intervals for each supply.

Moisture contents of fine aggregate shall be determined at any time when a change in moisture

content is expected.

If the Contractor proposes to change the source of aggregate, the Project Manager shall be informed

in advance and in no case less than 3 weeks before the new aggregate shall be used.

3.3.3 Composition of Concrete

A) Classes of Concrete

Page 30 of 69


Concrete with cement type as specified for incorporation in the Works shall be of the classes indicated

on the Drawings and shall comply with Table 3.3.

Table 3.3 Concrete classes

Concrete Class

28 days Characteristic Strength (N/mm

2) (15cmx15cm15cm Cube)

Maximum Size of Coarse Aggregate

(mm)

Minimum Cement

Content (Kg/m3)

M7 7

40

20

180

210

M10 10

40

20

210

240

M15 15

40

20

250

280

M20 20

40

20

300

320

M25 25

40

20

340

360

M30 30

40

20

370

400

M35 35

40

20

400

430

B) Proportioning

When designing the concrete mix, the Contractor shall consider the following conditions:

1) Strength

The class of the concrete is to be as shown on the Drawings. The class is the specified characteristic

cube strength at 28 days. Concrete mixes shall be designed to comply with Specifications Section

3.3.4.

2) Water/Cement Ratio

The ratio of free water to cement when using saturated surface dry aggregate shall be as low as

possible and not exceed 0.50 by weight for all concrete, except for blinding concrete where it shall not

exceed 0.6, unless approved by the Project Manager.

Page 31 of 69


For concrete in barriers, edge beams and bridge decks directly exposed to traffic or concrete in pile

caps or abutments in contact with the ground, the water cement ratio shall not exceed 0.45, unless


3) Minimum Cement Content

As indicated for the respective class in Table 3.3

4) Minimum Filler Content

Filler content (fine aggregate less than 0.25 mm and cement) shall not be less than as follows (except

for mass concrete).

Maximum coarse aggregate size (mm) 20 40

Minimum filler content (kg/m3 of concrete) 435 350

5) Coarse Aggregate

The maximum size of coarse aggregate will generally be stated on the Drawings; either 40 mm or 20

mm, in accordance with Table 3.3. Grading and quality is to comply with the requirements of Section

3.3.1.

6) Fine Aggregate

The grading and quality is to comply with the requirements of Section 3.3.1.

7) Workability

The concrete shall be of suitable workability to obtain full compaction. Slumps measured in

accordance with approved standard procedure shall not exceed 75 mm unless otherwise indicated on

the Drawings or approved by the Project Manager.

C) Trial Mixes

After the Contractor has received approval for the cement and aggregate to be used, he shall prepare

trial mixes with concrete of designed proportions to prove and establish workability, strength, water

cement/ratio, surface criteria etc. Methods of transporting fresh concrete and the compaction

equipment shall be considered. The trial mixes shall be made and compacted in the presence of the

Project Manager, using the same type of plant and equipment as will be used for the Works.

From each trial mix, cylinders or cubes shall be made and tested in accordance with Section 3.3.4.

From the same mix as that from which the test specimens are made, the workability of the concrete

shall be determined by the slump test. The remainder of the mix shall be cast in a wooden mould and

compacted. After 24 hours the sides of the mould shall be struck and the surface examined in order to

satisfy the Project Manager that an acceptable surface can be obtained with the mix.

The trial mix proportions should be approved if the required strength is obtained from tests carried out

in accordance with Section 3.3.4 and the consistency and surface is to the satisfaction of the Project

Manager.

Page 32 of 69


When a mix has been approved, no variations shall be made in the mix proportions, or in the type,

size, grading zone or source, of any of the constituents without the consent of the Project Manager,

who may require further trial mixes to be made before any such variations are approved.

Until the results of trial mixes for a particular class have been approved by the Project Manager, no

concrete of the relevant class shall be placed in the Works.

When the Contractor intends to purchase factory-made precast concrete units, trial mixes may be

dispensed with provided that evidence is given to satisfy the Project Manager that the factory regularly

produces concrete which complies with the Specifications. The evidence shall include details of mix

proportions, water/cement ratios, slump tests and strengths obtained at 28 days.

3.3.4 Control of Concrete Quality

A) General

The Contractor shall assume the full responsibility for the quality of the concrete conforming to these

Specifications and this responsibility shall not be relieved by the testing carried out and approved by

the Project Manager.

The Contractor shall thus at his own discretion establish additional testing procedures as necessary.

B) Control of Concrete Production

1) Materials

Materials used shall be tested in accordance with the relevant sections of this specification.

2) Plant and Equipment

Batching plants will be tested by the Contractor in a manner approved by the Project Manager before

any major concrete casting and at any other time if requested by the Project Manager. The concreting

plant and equipment shall have a capacity for atleast 80m3 of concreting per day.

3) Fresh Concrete

The frequency of slump tests shall be as directed by the project Manager, with at least one test per 25

m3 of concrete.

C) Control of Strength

C.1) Sampling and Testing

The Contractor shall take samples of the concrete for testing. The number, frequency and location

shall be decided by the Project manager. A minimum of 3 concrete cubes should be taken for each

day’s casting, or for every 15 m3

of concrete cast in large pours. The slump of concrete samples shall

be measured.

The procedures for sampling and making cubes and testing them shall be as described in IS: 1199/IS:

516 (or ASTM C873 / C873M - 04e1.)

C.2) Strength Requirement

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The results of the testing shall conform to the strength requirements according to IS: 456 or to any

mathematically correct statistical test for each casting section.

C.2.1) General

The characteristic strength of concrete is the 28 days strength below which not more than 5% of the

test results may be expected to fall.

C.2.2) Target Mean Strength

The concrete mix should be designed to have a mean strength greater than the required characteristic

strength by at least the current margin.

The current margin for each particular type of concrete mix shall be determined; it may be taken as

having the smaller of the values given by (1) or (2) below.

C.2.2.1)1.64 times the standard deviation of tests on at least 100 separate batches of concrete of

nominally similar proportions of similar materials and produced over a period not exceeding 12

months by the same plant under similar supervision.

C.2.2.2)1.64 times the standard deviation of tests on at least 40 separate batches of concrete of

nominally similar proportions of similar materials and produced over a period exceeding 5 days but

not exceeding 6 months by the same plant under similar supervision.

Where there are insufficient data to satisfy (1) or (2) above, the margin for the initial mix design should

be taken as one-thirds of the characteristic strength for concrete. This margin should be used as the

current margin only until sufficient data are available to satisfy (1) or (2) above. However, when the

required characteristic strength approaches the maximum possible strength of concrete made with a

particular aggregate, a smaller margin may be permitted by the Project Manager for the initial mix

design.

C.2.3) Testing Plan

Each cube shall be made from a single sample taken from randomly selected batches of concrete.

Compliance with the specified characteristic strength may be assumed if:

1) The average strength determined from any group of four consecutive test cubes exceeds the

specified characteristic strength by not less than 0.5 times the current margin, and

2) Each individual test result is greater than 85% of the specified characteristic strength.

The current margin should be taken to be one-thirds (1/3) of the specified characteristic strength for

concrete, unless as mentioned above a smaller margin has been established to the satisfaction of the

Project Manager.

If only one cube result fails to meet the second requirement then that result may be considered to

represent only the particular batch of concrete from which that cube was taken provided the average

strength of the group satisfies the first requirement.

If more than one cube in a group fails to meet the second requirement or if the average strength of

any group of four consecutive test cubes fail to meet the first requirement then all the concrete in all

the batches represented by all such cylinders shall be deemed not to comply with the strength

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requirements. For the purposes of this sub-Section, the batches of concrete represented by a group of

four consecutive test cylinder/cubes shall include the batches from which samples were taken to

make the first and the last cubes in the group of four, together with all the intervening batches.

C.2.4) Action to be taken in the event of Non-Compliance with the Testing Plan

When the average strength of four consecutive test cubes fail to meet the first requirement in (F),

above, the mix proportions of subsequent batches of concrete should be modified to increase the

strength.

The action to be taken in respect of the concrete which is represented by the test- cubes which fail to

meet either of the requirements (or not by correct statistical proof can be verified to have the required

strength) shall be determined by the Project Manager. This may range from qualified acceptance in

less severe cases, to rejection and removal in the most severe cases.

The Project Manager may also require the Contractor at his own expenses to prove statistically the

strength, by boring out cores and testing them according to a program approved by the Project

Manager. The age of the concrete and degree of hardening at the time of the new testing shall be

considered. The equivalent cylinder/cube strength shall comply the minimum characteristic strength or

as decided by the Project Manager.

D) Control of Hardening

If the Contractor wants to remove forms and scaffolding earlier than specified herein, extra test

specimens shall be cast by the Contractor in accordance with the instruction of the Project Manager.

These specimens shall be tested the day before removal of the form. On the basis of the test results

the Project Manager shall take the final decision on the time for the removal of forms.

3.4 Construction Methods

3.4.1 General

The Contractor shall in due time and as soon as possible present and discuss his construction

methods and work program with the Project Manager and shall obtain his approval before

commencement of any work.

The Contractor shall maintain an adequate number of trained and experienced supervisors and

foremen at the Site to supervise and control the work.

All construction, other than concrete, shall conform to the requirements prescribed in other Sections of

the Specifications, for the particular items of work comprising the complete structure.

3.4.2 Care and Storage of Concrete Materials

A) Storage of Cement

All cement shall be stored in suitable weatherproof buildings or silos which will protect the cement

from dampness. These buildings or silos shall be placed in locations approved by the Project

manager. Provisions for storage shall be ample, and the shipments of cement as received shall be

separately stored in such manner as to provide easy access for the identification and inspection of

each shipment. Storage buildings shall have a capacity for the storage of a sufficient quantity of

cement to allow sampling at least 14 days before the cement is to be used. Cement shall meet the

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test requirements at any time and any cement stored for an elongated time shall be checked and

tested before use regardless of whether it has previously been tested.

B) Storage of Aggregates

Aggregates shall be so stored as to prevent the inclusion of foreign material. Aggregates shall not be

placed upon the finished roadbed. Aggregates of different sizes and kinds shall be placed in different

stockpiles. Stockpiles of blended coarse aggregates shall be built up in successive horizontal layers

not more than 1 meter thick. Each layer shall be completed before the next is started. Should

segregation occur, the aggregates shall be recombined to conform to the grading requirement.

Washed aggregates and aggregates produced or manipulated by methods which involve the use of

water shall be allowed to drain at least 12 hours before use.

3.4.3 Preparations before Casting

Before any major casting, the Contractor shall prepare a complete “casting program” describing staff

and labor, consumption of materials, plant, tools and equipment, reserves of materials, standby plant

and equipment, proposed means of handling and placing the concrete, quality controls etc.

No concrete shall be mixed and placed until the Contractor’s casting program has been approved in

writing by the Project Manager.

Equipment and tools necessary for handling materials and performing the work, and satisfactory to

the Project Manager as to design, capacity, and mechanical condition, shall be at the site of the work

before casting is started.

If any equipment is not maintained in full working order, or if the equipment as used by the Contractor

proves inadequate to obtain the result prescribed, such equipment shall be repaired or other suitable

equipment substituted or added at the discretion of the Project manager.

3.4.4 Measuring Materials

All material in the mix shall be proportioned by weight or volume, subject to the approval of the Project

manager.

When volume batching is proposed by the Contractor, the exact proportions must be converted from

trial mix weights to volumes, from bulk densities determined in the laboratory. Written approval from

the Project Manager is required.

3.4.5 Mixing Concrete

A) General

All concrete shall be mixed in batch mixers, either at the site of construction, at a central plant, or in

transit. Each mixer shall have attached to it in a prominent place, a manufacturer’s plate showing the

capacity of the drum in terms of mixed concrete and the speed of rotation of the mixing drum.

B) Mixers at Local Site of Construction

Mixers at local sites shall be approved drum-type capable of combining the aggregate, cement, and

water into a thoroughly mixed and uniform mass within the specified mixing period and of discharging

the mixture without segregation. The mixer shall be equipped with a suitable charging hopper, water

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storage and a water measuring device, accurate within 1%. Controls shall be so arranged that the

water can be applied only while the mixer is being charged. Suitable equipment for discharging the

concrete shall be provided. The mixer shall be cleaned at suitable intervals. The pickup and throw-

over blades in the drum shall be replaced when they have lost 10% of their depth.

The mixer shall be operated at a drum speed of between 15 and 20 revolutions per minute. The

batched materials shall be so charged into the drum that a portion of the water shall enter in advance

of the cement and aggregates and the water shall continue to flow into the drum for a minimum time

of 5 seconds after all the cement and aggregates are in the drum. Mixing time shall be measured from

the time all materials except water are in the drum and shall, in the case of mixers having a capacity

of 1 cubic Meter or less, not be less than 50 seconds nor more than 70 seconds. In the case of dual

drum mixers, the mixing time shall not include transfer time. The contents of an individual mixer drum

shall be removed before a succeeding batch is emptied therein. Any concrete mixed less than the

specified minimum time shall be discarded and disposed of by the Contractor at his own expense.

The volume of concrete mixed per batch shall not exceed the mixer’s nominal capacity in cubic feet or

cubic meters as shown on the manufacturer’s guaranteed capacity standard rating plate on the mixer;

except that an overload up to 20% of the mixers nominal capacity may be permitted provided concrete

test data for strength, segregation and uniform consistency are satisfactory, and provided no spillage

of concrete takes place.

Re-tempering concrete by adding water or by other means shall not be permitted. Concrete which is

not of the required consistency at the time of placement shall not be used and shall be discarded and

disposed of by the Contractor at his own expense.

C) Central Plant Mixers

These mixers shall be of approved drum type capable of combining the aggregate, cement and water

into a thoroughly mixed and uniform mass within the specified mixing period and of discharging the

mixture without segregation. Central plant mixers shall be equipped with an acceptable timing device

that will not permit the batch to be discharged until the specified mixing time has elapsed. The water

system for a central mixer shall be either a calibrated measuring tank or a meter and shall not

necessarily be an integral part of the mixer.

The mixers shall be cleaned at suitable intervals. They shall be examined daily for changes in interior

condition. The pick up and throw-over blades in the drum shall be replaced when they have lost 10%

of their depth.

In addition to the requirements for mixers at local sites detailed above, central plant mixers which

have a capacity of between 2 and 5 cubic meters, or greater than 5 cubic meters, should have a

minimum mixing time of 90 and 120 seconds respectively, provided tests indicate that the concrete

produced is equivalent in strength and uniformity to that attained as stated in the preceding

paragraphs.

Mixed concrete shall be transported from the central mixing plant to the site of work in agitator trucks

or, upon written permission of the Project Manager, in non-agitator trucks. Delivery of concrete shall

be so regulated that placing is at a continuous rate unless delayed by the placing operations. The

intervals between deliveries of batches shall not be so great as to allow the concrete in place to

harden partially, and in no case shall such an interval exceed 30 minutes.

D) Agitator Trucks

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Unless otherwise permitted in writing by the Project Manager, agitator trucks shall have watertight

revolving drums suitably mounted and shall be capable of transporting and discharging the concrete

without segregation. The agitating speed of the drum shall not be less than two or more than six

revolutions per minute. The volume of mixed concrete permitted in the drum shall not exceed the

manufacturer’s rating nor exceed 80% the gross volume of the drum.

Upon approval by the Project manager, open-top, revolving-blade truck mixers may be used in lieu of

agitating trucks for transportation of central plant mixed concrete.

Gross volume of agitator bodies expressed in cubic feet or cubic Meters shall be supplied by the

mixer manufacturer. The interval between introduction of water into the mixer drum and final

discharge of the concrete from the agitator shall not exceed 45 minutes. During this interval the mix

shall be agitated continuously.

E) Non-Agitator Trucks

Bodies of non-agitating equipment shall be smooth, water-tight metal containers equipped with gates

that will permit control of the discharge of the concrete. Covers shall be provided when needed for

protection against the weather.

The non-agitating equipment shall permit delivery of the concrete to the site of the work in a

thoroughly mixed and uniform mass with a satisfactory degree of discharge.

Uniformity shall be satisfactory if samples from the one-quarter and three quarter points of the load do

not differ by more than 30 mm in slump. Discharge of concrete shall be completed within 30 minutes

after the introduction of the mixing water to the cement and aggregate.

F) Truck or Transit Mixers

These shall be equipped with electrically actuated counters by which the number of revolutions of the

drum or blades may readily be verified and the counters shall be actuated at the commencement of

mixing operations at designated mixing speeds. The mixer when loaded shall not be filled to more

than 60% of the drum gross volume. The mixer shall be capable of combining the ingredients of the

concrete into a thoroughly mixed and uniform mass and of discharging the concrete with a satisfactory

degree of uniformity.

Except when intended for use exclusively as agitators, truck mixers shall be provided with a water

measuring device to measure accurately the quantity of water for each batch. The delivered amount

of water shall be within plus or minus 1% of the indicated amount.

Truck mixers may be used for complete mixing at the batch plant and as truck agitators for delivery of

concrete to job sites, or they may be used for complete mixing of the concrete at the job site. They

shall either be a closed watertight revolving drum or an open top revolving blade or paddle type.

The amount of mixing shall be designated in number of revolutions of the mixer drum. When a truck

mixer is used for complete mixing, each batch of concrete shall be mixed for between 70 and 100

revolutions of the drum or blades at the rate of rotation designated by the manufacturer of the

equipment as the “mixing speed”. Such designation shall appear on a metal plate attached to the

mixer. If the batch is at least 0.5 cubic meters less than guaranteed capacity, the number of

revolutions at mixing speed may be reduced to not less than 50. Mixing in excess of 100 revolutions

shall be at the agitating speed. All materials, including the mixing water, shall be in the mixer drum

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before actuating the revolution counter which will indicate the number of revolutions of the drum or

blades.

When wash water (flush water) is used as a portion of the mixing water for the succeeding batch, it

shall be accurately measured and taken into account in determining the amount of additional mixing

water required. When wash water is carried on the truck mixer, it shall be carried in a compartment

separate from the one used for carrying or measuring the mixing water. The Project manager will

specify the amount of wash or flush water, when permitted, any may specify a “dry” drum if wash

water is used without measurement or without supervision.

When a truck is used for complete mixing at the batch plant, mixing operations shall begin within 30

minutes after the cement has been added to the aggregate. After mixing, the truck mixer shall be used

as an agitator, when transporting concrete, at the speed designated by the manufacturer of the

equipment as agitating speed. Concrete discharge shall be completed within 45 minutes after the

addition of the cement to the aggregates. Each batch of concrete delivered at the job site shall be

accompanied by a time slip issued at the batching plant, bearing the time of departure there from.

When the truck mixer is used for the complete mixing of the concrete at the job site, the mixing

operation shall begin within 30 minutes after the cement has been added to the aggregates.

The rate of discharge of the plastic concrete from the mixer drum shall be controlled by the speed of

rotation of the drum in the discharge direction with the discharge gate fully open.

3.4.6 Handling and Placing Concrete

The temperature of concrete at the time of placing shall not be below 50C or above 35°C.

In preparation for the placing of concrete all sawdust, chips and other construction debris and

extraneous matter shall be removed from the interior of forms. Struts, stays and braces, serving

temporarily to hold the forms in correct shape and alignment, pending the placing of concrete at their

locations, shall be removed when the concrete placing has reached an elevation rendering their

service unnecessary. These temporary members shall be entirely removed from the forms and not

buried in the concrete.

Concrete must reach its final position in the forms within 20 minutes of the completion of mixing, or as

directed by the Project manager.

Concrete shall be placed so as to avoid segregation of the materials and the displacement of the

reinforcement. The use of long troughs, chutes and pipes for conveying concrete from the mixer to the

forms shall be permitted only on written authorization of the Project manager. In case an inferior

quality of concrete is produced by the use of such conveyors, the Project manager may order

discontinuance of their use and the institution of a satisfactory method of placing.

Open troughs and chutes shall be of metal or metal lined. Where long steep slopes are required, the

chutes shall be equipped with baffles or be in short lengths that reverse the direction of movement.

All chutes, troughs and pipes shall be kept clean and free from coatings of hardened concrete by

thoroughly flushing with water after each run. Water used for flushing shall be discharged clear of the

structure.

When placing operations would involve dropping the concrete more than 1 .5 m, it shall be deposited

through sheet metal or other approved pipes. As far as practicable, the pipes shall be kept full of

concrete during placing and their lower ends shall be kept buried in the newly placed concrete. After

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initial set of the concrete, the forms shall not be jarred and no strain shall be placed on the ends of

reinforcement bars which project.

Concrete, during and immediately after depositing, shall be thoroughly compacted. The compaction

shall be done by mechanical vibration subject to the following provisions:

1) The vibration shall be internal unless special authorization of other methods is given by the

Project Manager or as provided herein.

2) Vibrators shall be of a type and design approved by the Project manager. They shall be

capable of transmitting vibration to the concrete at frequencies of not less than 4,500

impulses per minute.

3) The intensity of vibration shall be such as to visibly affect a mass of concrete of 20 mm slump

over a radius of at least 450 mm.

4) The Contractor shall provide a sufficient number of vibrators to properly compact each batch

immediately after it is placed in the forms.

5) Vibrators shall be manipulated to thoroughly work the concrete around the reinforcement and

embedded fixtures, and into the corners and angles of the forms.

Vibration shall be applied at the point of deposit and in the area of freshly deposited concrete. The

vibrators shall be inserted and withdrawn from the concrete slowly. The vibration shall be of sufficient

duration and intensity to thoroughly compact the concrete, but shall not be continued so as to cause

segregation. Vibration shall not be continued at any one point to the extent that localized areas of

grout are formed.

Application of vibrators shall be at points uniformly spaced and not further apart than twice the radius

over which the vibration is visibly effective.

6) Vibration shall not be applied directly or through the reinforcement to sections or layers of

concrete which have hardened to the degree that the concrete ceases to be plastic under

vibration. It shall not be used to make concrete flow in the forms over distances so great as to

cause segregation, and vibrators shall not be used to transport concrete in the forms.

7) Vibration shall be supplemented by such spading as is necessary to ensure smooth surfaces

and dense concrete along form surfaces and in corners and locations impossible to reach

with the vibrators.

8) The provisions of this Section shall also apply to precast piling, concrete cribbing and other

precast members except that, if approved by the Project Manager, the manufacturer’s

methods of vibration may be used.

Concrete shall be placed in horizontal layers not more than 600 mm thick except as hereinafter

provided. When less than a complete layer is placed in one operation, it shall be terminated in a

vertical bulkhead. Each layer shall be placed and compacted before the preceding batch has taken

initial set to prevent injury to the green concrete and avoid surfaces of separation between the

batches. Each layer shall be compacted so as to avoid the formation of a construction joint with a

preceding layer which has not taken initial set.

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When the placing of concrete is temporarily discontinued, the concrete, after becoming firm enough to

retain its form, shall be cleaned of laitance and other objectionable material to a sufficient depth to

expose sound concrete. To avoid visible joints as far as possible upon exposed faces, the top surface

of the concrete adjacent to the forms shall be smoothed with a trowel. Where a “feather edge” might

be produced at a construction joint, as in the sloped top surface of a wing wall, an inset form shall be

used to produce a blocked out portion in the preceding layer which shall produce an edge thickness of

not less than 150 mm in the succeeding layer. Work shall not be discontinued within 450 mm of the

top of any face, unless provision has been made for a coping less than 450 mm thick, in which case, if

permitted by the Project manager, a construction joint may be made at the underside of the coping.

Immediately following the discontinuance of placing concrete all accumulations of mortar splashed

upon the reinforcement steel and the surfaces of forms shall be removed. Dried mortar chips and dust

shall not be puddle into the unset concrete. If the accumulations are not removed prior to the concrete

becoming set, care shall be exercised not to injure or break the concrete-steel bond at and near the

surface of the concrete, while cleaning the reinforcement steel.

For simple spans, concrete shall preferably be deposited by beginning at the centre of the span and

working from the centre toward the ends. Concrete in girders shall be deposited uniformly for the full

length of the girder and brought up evenly in horizontal layers. For continuous spans, the concrete

placing sequence shall be as shown on the plans or agreed on by the Project manager.

Concrete in slab and girder haunches less than 1 .0 Meter in height shall be placed at the same time

as that in the girder stem.

Concrete in slab spans shall be placed in one continuous operation for each span unless otherwise

provided.

Concrete in T-beam or deck girder spans may be placed in one continuous operation if permitted by

the Project manager.

Concrete in columns and pier shafts shall be placed in one continuous operation, unless otherwise

directed.

Unless otherwise permitted by the Project Manager, no concrete shall be placed in the superstructure

until the column forms have been stripped sufficiently to determine the character of the concrete in the

columns. The load of the superstructure shall not be applied to the supporting structures until they

have been in place at least 14 days, unless otherwise permitted by the Project Manager.

Pneumatic placing of concrete shall be permitted only if authorized by the Project Manager. The

equipment shall be so arranged that vibration does not damage freshly placed concrete.

Where concrete is conveyed and placed by pneumatic means the equipment shall be suitable in kind

and adequate in capacity for the work. The machine shall be located as close as practicable to the

place of deposit. The position of the discharge end of the line shall not be more than 3 Meters from

the point of deposit. The discharge lines shall be horizontal or inclined upwards from the machine. At

the conclusion of placement the entire equipment shall be thoroughly cleaned.

Placement of concrete by pumping shall be permitted only if authorized by the Project Manager. The

equipment shall be so arranged that vibrations do not damage freshly placed concrete. Where

concrete is conveyed and placed by mechanically applied pressure, the equipment shall be suitable in

kind and adequate in capacity for the work. The operation of the pump shall be such that a continuous

stream of concrete without air pockets is produced. When pumping is completed, the concrete

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remaining in the pipeline, if it is to be used, shall be ejected in such a manner that there is not

contamination of the concrete or separation of the ingredients. After this operation, the entire

equipment shall be thoroughly cleaned.

3.4.7 Perforations and Embedment of Special Devices

The Contractor is responsible for determining in advance of making any concrete pours, all

requirements for perforation of concrete sections or embedment therein of special devices of other

trades, such as conduits, pipes, weep holes, drainage pipes, fastenings, etc. Any concrete poured

without prior provision having been made, shall be subject to correction at the Contractor’s expense.

Special devices to be embedded:

Expansion joints

Drain outlets including fixing bolts for down pipes

Bolts and inserts for sign posts

Bolts and inserts for various purposes regarding inspection and maintenance as directed by the Project Manager

Other devices not mentioned above shall be shown on the Drawings, or directed by the Project

Manager.

3.4.8 Finishing Concrete Surfaces

One of the following types of finishing shall be applied to concrete surfaces:

Type A - Concrete Decks

Immediately after placing concrete, concrete decks shall be struck off using templates to provide

proper crowns and shall be finished smooth to the correct levels. Finish shall be slightly but uniformly

roughened by brushing. The finished surface shall not vary more than 10 mm from a 3 Meter straight

edge placed in any direction on the roadway. Deviation from the grade line shall not be more than +

30 mm in any 20 Meter length.

Type B - Kerb and Sidewalk Surface

Exposed faces of kerbs and sidewalks shall be finished to true lines and grades. The kerb surface

shall be wood floated to a smooth but not slippery finish. Sidewalk surfaces shall be slightly but

uniformly roughened by brushing.

Type C - Ordinary Finish

An ordinary finish is defined as the finish left on a surface after the removal of the forms when all

holes left by form ties have been filled, and any minor surface defects have been repaired. The

surface shall be true and even, free from depressions or projections.

The concrete in bridge seats, caps, and tops of walls shall be struck off with a straight edge and

floated to true grade. Under no circumstances shall the use of mortar topping for concrete surfaces be

permitted.

Type D - Rubbed Finish

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After the removal of forms the rubbing of concrete shall be started as soon as its condition permits.

Immediately before starting this work the concrete shall be kept thoroughly saturated with water for a

minimum period of three hours. Sufficient time shall have elapsed before the wetting down to allow

the mortar used in patching to have thoroughly set. A medium coarse carborundum stone shall be

used for rubbing a small amount of mortar on the face. The mortar used shall be composed of cement

and fine aggregate mixed in the same proportions as that used in the concrete being finished.

Rubbing shall be continued until all form marks, projections, and irregularities have been removed, all

voids filled, and a uniform surface has been obtained. The paste produced by this rubbing shall be left

in place at this time. The final finish shall be obtained by rubbing with a fine carborundum stone and

water until the entire surface is of a smooth texture and uniform color.

After the final rubbing has been completed and the surface has dried, burlap shall be used to remove

loose powder. The final surface shall be free from unsound patches, paste, powder and objectionable

marks.

Type E – Bush hammer Finish

Bush hammering shall be carried out by treating the surface with an approved heavy duty power

hammer fitted with a multi-point tool which shall be operated over the surface to remove 5 to 6 mm of

concrete paste and expose maximum areas of coarse aggregate.

Aggregate left embedded shall not be fractured or loose. 25 mm wide bands at all corners and arises

shall be left as cast. The finish surface shall be even and of uniform appearance and shall be washed

with water upon completion.

Type F - Ribbed Finish

Ribs shall be vertical and to the dimensions shown on the Drawings. The direction of the grain of the

timber forming the ribs shall be vertical.

3.4.9 Construction Joints

A) General

Construction joints shall be made only where located on the plans or shown in the pouring schedule,

unless otherwise approved by the Project manager.

If not detailed on the plans, or in the case of emergency, construction joints shall be placed as

directed by the Project manager. Shear keys or inclined reinforcement shall be used where necessary

to transmit shear or bond the two sections together.

B) Bonding

Before depositing new concrete on or against concrete which has hardened, the forms shall be re-

tightened. The surface of the hardened concrete shall be roughened as required by the Project

manager, in a manner that does not leave loosened particles of aggregate or damaged concrete at

the surface. It shall be thoroughly cleaned of foreign matter and laitance, and saturated with water. To

ensure an excess of mortar at the juncture of the hardened and the newly deposited concrete, the

cleaned and saturated surfaces, including vertical and inclined surfaces, shall first be thoroughly

covered with a thin coating of mortar or neat cement grout against which the new concrete shall be

placed before the grout has attained its initial set.

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The placing of concrete shall be carried continuously from joint to joint. The face edges of all joints

which are exposed to view shall be carefully finished true to line and elevation.

3.4.10 Curing Concrete

All concrete surfaces shall be kept thoroughly wet for at least 7 days after placing. Bridge deck and

sidewalk slabs shall be covered with wet hessian immediately after final finishing of the surface. This

material shall remain in place for the full curing period or may be removed and replaced with sand

when the concrete has hardened sufficiently to prevent marking. In both cases the materials shall be

kept thoroughly wet for the entire curing period. All other surfaces if not protected by forms, shall be

kept thoroughly wet, either by sprinkling or by the use of wet burlap until the end of the curing period.

The wood forms are allowed to remain in place during the curing period, but they shall be kept moist

at all times to prevent openings at joints.

After a period of 7 days, the concrete shall be watered daily at certain intervals approved by the

Project Manager to avoid drying out of the surface. This shall take place during the following 2 weeks.

The water used shall be the same as used in concrete mixes unless otherwise approved by the

Project Manager.

Any proposal from the Contractor for the use of liquid membrane curing compound shall be subject to

the approval of the Project Manager.

3.4.11 Removal of Scaffolding and Formwork

Forms and scaffolding shall not be removed without the approval of the Project Manager. The Project

manager’s approval shall not relieve the Contractor of his Contract responsibilities. Any kentledge

blocks and bracing shall be removed at the same time as the forms and in no case shall any portion of

the wood forms be left in the concrete.

Forms used on exposed vertical faces shall remain in place for periods which shall be determined by

the Project Manager and normally not less than 3 days.

Supporting scaffolding and forms under slabs, beams and girders shall normally remain in place until

the full required strength of the concrete has been obtained. If a shorter period is requested, this may

be permitted by the Project Manager. In such case, special test specimens (see Section 3.3.4) shall

be cast to monitor the hardening.

All structures shall be fully stripped before adjacent structures are cast.

3.4.12 Repair of Concrete

As soon as the form has been stripped, the Contractor shall advise the Project Manager who shall

inspect the concrete before any improvement of the surface takes place.

All wire or metal devices used for securing the formwork which project from or appear on the surface

of the finished concrete shall be removed or cut back to at least a depth equal to the required

reinforcement cover. All holes and pockets so formed shall be filled with cement mortar mixed in the

same proportions as the fine aggregate to cement of the concrete mix used for that particular section

of the structure, after the surface to be patched has been thoroughly cleaned and wetted to receive

the patch.

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Excessive honeycombing shall be sufficient to cause rejection of portions of the structure containing

this honeycombing. The Contractor, on receipt of written orders from the Project manager, shall

remove and rebuild such portions of the structure at his own expense.

Smaller honeycombing and other defects can be repaired if permitted by the Project Manager.

Structural, maintenance and aesthetical points of view shall be taken into consideration before such

approval, if any, may be given. The method of repair shall be approved by the Project manager and

an extension of period for a certain part of the performance bond may be required.

3.4.13 Depositing Concrete under Water

Concrete shall not be deposited in water except with the approval of the Project manager and under

his immediate supervision; and in this case the method of placing shall be as defined in this Section.

Concrete placed under water shall be carefully placed in a compact mass, in its final position, by

means of a tremie tube and shall not be disturbed after being deposited. Special care must be

exercised to maintain still water at the point of deposit. Concrete shall not be placed in running water.

The method of depositing concrete shall be so regulated as to produce approximately horizontal

surfaces.

Concrete seals shall be placed in one continuous operation. When a tremie tube or pipe is used, it

shall consist of a tube or pipe not less than 150 mm in diameter. All joints in the tube shall be

watertight. The means of supporting the tremie tube shall be such as to permit free movement of the

discharge end over the entire top of the concrete and to permit its being lowered rapidly when

necessary to choke off or retard the flow. The tremie tube shall be filled by a method that prevents

washing of the concrete. The discharge end shall be completely submerged in concrete at all times

and the tremie tube shall be kept full. Concrete slump shall not be less than 150 mm.

Dewatering shall proceed only when the concrete seal is considered strong enough to withstand any

pressure to be exerted upon it. This time shall be decided by the Project Manager.

All laitance or other unsatisfactory material shall be removed from the exposed surface by scraping,

jetting, chipping or other means, which do not injure the seal unduly.

3.4.14 Factory Made Precast Concrete Elements

Any supplier of precast concrete elements shall be approved in writing by the Project manager. Such

approval can be withdrawn at any time.

Concrete work in precast concrete elements shall fully conform to all relevant Sections of these

Specifications.

The supplier shall maintain laboratory facilities of the same standard as the site laboratory.

Unless otherwise approved by the Project manager, precast concrete members shall not be moved

from the casting position until the concrete has attained a compressive strength of 80% of the

specified 28 day strength, nor transported until it has developed strength of 90% of the specified 28

day strength.

Extreme care shall be exercised in handling and moving precast concrete members. Precast girders

and slabs shall be transported in an upright position. Shock shall be avoided and the points of support

and directions of the reactions with respect to the member shall be approximately the same during

Page 45 of 69


transportation and storage as when the member is in its final position. If the Contractor deems it

expedient to transport or store precast units in other than this position, this shall be at the Contractor’s

risk, after notifying the Project Manager of his intention to do so. Any rejected unit shall be replaced at

the Contractor’s expense by an acceptable unit.

Proposed details on the handling and transportation of precast concrete members shall be submitted

in writing by the Contractor, to the Project manager, for his approval.

Each precast member is to be uniquely and permanently marked so as to show its type, date of

casting and any other information required by the Project manager.

3.4.15 Control of Heat in Structures

In structures of major dimensions i.e., pile caps, etc. the heat deriving from the hardening of the

concrete shall be controlled by the Contractor. Temperature gradients introducing risk of cracking

shall not occur and the temperature shall not exceed 70°C.

The Contractor shall submit timely proposals for avoiding excessive heat generation, such as the

cooling of aggregates before mixing, to the Project manager for approval.

3.4.16 Loading

No superstructure load shall be placed upon finished bents, piers, or abutments until the Project

manager so directs but in no case shall any load of any kind be placed until the concrete has

completed curing.

The Contractor shall not place any temporary loads on deck slabs unless allowed by the Project

manager in writing. Bridge deck slabs shall be opened to traffic only when so directed by the Project

manager and generally not sooner than 28 days after the placing of the concrete has been completed.

3.4.17 Backfill to Structures

All spaces which have been excavated and the volumes of which are not occupied by the concrete

structure shall be backfilled and compacted with acceptable material in accordance with the

provisions of relevant specification and as directed by the Project Manager.

3.4.18 Cleaning Up

Upon completion of a structure and before final acceptance, the Contractor shall remove all forms and

scaffolding etc. down to 0.5 Meters below the finished ground line. Excavated, or useless materials,

rubbish etc. shall be removed from the Site and the Site shall be left in a neat and tidy condition

satisfactory to the Project Manager.


Concrete shall be measured by the number of cubic Meters of Class indicated on the Drawings

complete in place and accepted by the Project Manager. In computing quantities, the dimensions

used shall be those shown on the Drawings. No deduction from the measured quantity shall be made

for drainage, pipes less than 300 mm in diameter, conduits, chamfers, reinforcement bars, expansion

joints, water stops or pile heads embedded in concrete.

Reinforcing steel shall be measured for payment as described in Section 3.8.

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The concrete of grades shown on the Drawings and measured as provided in Section 3.5 shall be

paid for at the Contract unit prices per cubic Meter. The Contractor’s rates shall include materials,

mixing, transporting, placing and compacting the concrete. The rates shall also include all trial mixes

(as specified in Section 3.3.3), all conformance tests, all concrete finishings, the supply, placing and

building in of weep pipes or pipe sleeves, forming construction joints, forming holes or pockets not

exceeding 0.15 m3 each.

Payment for precast units shall include all concrete, formwork, finishing, transport and erection and

where applicable any bolts, bedding or other devices necessary to fix them in their permanent

position.

3.6 Formwork and Scaffolding

3.6.1 Scaffolding (Falsework)

Details, plans and structural calculations for scaffolding shall be submitted by the Contractor to the

Project manager for approval, but in no case shall the Project manager’s approval relieve the

Contractor of his contract responsibilities. All scaffolding shall be designed and constructed by the

Contractor to provide the necessary rigidity and to support dead and live loads without deflection or

deformation. The Project manager may require the Contractor to employ screw jacks or hardwood

wedges to take up any settlement in scaffolding and formwork, either before or during the placing of

concrete.

Tests may be required by the Project manger of materials proposed by the Contractor for scaffolding.

Test loadings of the completed scaffolding may also be required for the determination of flexibility and

strength. All expenses associated with testing shall be borne by the Contractor.

Scaffolding which cannot be founded on a satisfactory footing shall be supported on piles, which shall

be spaced, driven and removed in a manner approved by the Project manager. When the Contractor

wishes to support scaffolding on existing structures, he shall submit his proposals in due time to the

Project manager, in writing, including loads from the scaffolding. The Project manager will consider

the proposals and respond in writing.

Scaffolding shall be set to give the finished structure a camber, if indicated on the Drawings or

specified by the Project manager.

Scaffolding shall remain in place for periods which shall be determined by the Project manager.

The formwork shall be properly designed for the self-weight, weight of reinforcement, weight of fresh

concrete, various live loads imposed during the construction process (such as workmen and

equipment). Dumping of concrete, movement of construction equipment and action of the wind may

produce lateral forces which must be resisted by the form work to prevent lateral failure for which

suitable horizontal as well as diagonal bracings shall be provided. The permissible stresses in

bending, buckling load of props, permissible deflection of shuttering should not be exceeded.

In case the height of centering exceeds 3.50 Meters, the props may be provided in multi-stages.

Before the concreting is started, the props and wedges shall be thoroughly checked to see that these

are intact, and take suitable action in case these are loose. While the concreting is in progress, at

least one carpenter shall be readily available at the site. The carpenter shall keep a constant watch on

the props and take immediate remedial measures, as soon as any of these get loosened. Care shall

be taken that props and wedges do not get loose for a minimum period specified in Table 3.6.

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3.6.2 Formwork

Formwork shall include all temporary or permanent moulds for forming the concrete. Formwork shall

be of wood, metal or other approved materials and shall be built mortar tight and rigid enough to

maintain the concrete in position during placing, compacting, setting and hardening.

Formwork for exposed surfaces (“wrought form”) shall be made of dressed lumber of uniform

thickness with or without a form liner of an approved type or shall be of metal sufficiently rigid in itself

with no surface blemishes that will impair the quality of the concrete surface finish. No rusty or bent

metal forms shall be used. Exposed concrete arises shall be provide with formed chamfers, as

indicated on the Drawings or instructed by the Project manager.

Rough lumber may be used for surfaces that will not be exposed in the finished structure (“rough

form”).

All lumber shall be sound, free from warps and twists, sap, shakes, large or loose knots, wavy edge or

other defects affecting the strength or appearance of the finished structure.

All forms shall be set and maintained true to the line designated until the concrete is sufficiently

hardened. Forms shall remain in place for periods, which shall be determined by the Project manager.

When forms appear to be unsatisfactory in any way, either before or during the placing of concrete,

the Project manager may order the work stopped until the defects are corrected.

If requested, the Contractor shall submit to the Project manager working drawings of the forms and

also, if requested, calculations to verify the rigidity and strength of the forms.

The shape, strength, rigidity, water tightness and surface smoothness of reused formwork shall be

maintained at all times. Any warped or bulged lumber must be re-sized before being reused.

Formwork that is unsatisfactory in any respect shall not be reused.

Metal ties or anchorages within the form shall be so constructed as to permit their removal to a depth

of at least 50 mm from the face without injury to the concrete. All fittings for metal ties shall be of such

design that, upon their removal, the cavities which are left will be of the smallest possible size. The

cavities shall be filled with cement mortar and the surface left sound, smooth, even and uniform in

color.

Formwork shall be so constructed that easy cleaning out of any extraneous material inside the

formwork can be achieved without disturbing formwork already checked and approved by the Project

manager.

Formwork shall be treated with approved non-staining oil or saturated with water, to facilitate

formwork removal. The Project manager may require trials to be carried out before approval is given

for the use of a particular type of oil, to ascertain that the oil proposed by the Contractor does not

discolor or injure the finished concrete face in any way.

Before placing any concrete, all shavings, loose binding wires, soil, rubbish and all foreign matter shall

be removed from the formwork and the formwork shall be carefully and thoroughly washed with water.

If not indicated otherwise, the following tolerances of the finished concrete structures shall apply:

Foundations: horizontally ±30 mm; vertically ±20 mm

Piers: Horizontally±20 mm, vertically~ 10mm, inclination 1:400

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Dimensions of other structural members: + 10 mm, -5 mm

Edge beams and parapets shall be made to such accuracy that no deviations from the correct

alignment are visible.

The cross sectional areas of the superstructure of bridges shall in no place deviate more than 3%

from the theoretically correct cross sectional areas.

Anchors for bearings, expansion joints, railings, etc. shall be placed within the tolerances indicated on

the Drawings or specified by the Project manager.

3.6.3 Surface Treatment for Shuttering

The surfaces of timber shuttering that would come in contact with concrete shall be well wetted and

coated with soap solution, raw linseed oil or form oil of approved manufacture, to prevent adhesion of

concrete to form work. Use of polythene sheets shall not be permitted. Soap solution, for the purpose

shall be prepared by dissolving yellow soap in water to get the consistency of paint. Inside surfaces of

forms shall be thoroughly cleaned before application of any of the materials mentioned above.

Release agents shall be applied strictly in accordance with the manufacturers’ instructions and shall

not be allowed to come in contact with any reinforcement. Re-use of the shuttering shall be permitted

only after the inside surface has been thoroughly cleaned in the manner described above.

Contractor shall give the Project manager due notice before placing any concrete in the forms to

permit him to inspect and accept the form work as to its strength alignment and general fitness, but

such inspection shall not relieve the contractor of his responsibility for safety of workman, machinery,

materials and for results obtained.

3.6.4 Camber

Cambers both along and across the bridge shall be provided as per the lines and levels shown in the

design drawings or as directed by the Project manager. The scaffold and the formwork shall be so

assembled as to provide for such camber. For cantilevers, the camber at free end shall be 1/50th of

the projected length or as directed by the Project manager.

3.6.5 Approval of Scaffolding and Formwork

If plans and calculations of scaffolding and formwork are sought by the Project Manager, no

construction of such scaffolding and formwork shall take place before approval by the Project

manager, in writing. Such approval shall not relieve the Contractor of his responsibilities under the

Contract for the adequacy of scaffolding and formwork.

The Project manager shall have reasonable time for his examination of the Contractor’s plans and

calculations, especially if scaffolding is introducing temporary loading on new structures. The

Contractor shall not be granted time extension due to awaiting such approval.

The Project manager shall inspect all formwork and scaffolding and no concrete shall be placed until

the Project manager’s approval has been given. Such approval shall not relieve the Contractor of any

of his responsibilities under the Contract for the successful completion of the structure.

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3.6.6 Special Formwork

For special type of work-locations like tall structures etc. use of special types of formwork like moving

or climbing forms shall be permitted. The details of such formworks along with the sequence of

working shall be approved by the Project manager before their erection.

3.6.7 Removal of Form Work

No formwork or any part thereof shall be removed without prior approval of the Project manager. The

formwork shall be so removed as not to cause any damage to concrete due to shock or vibration. In a

slab and beam construction, sides of beam shall be stripped first, then the under sides of slab and

lastly the underside of the beam. Formwork must be so designed that they can be stripped in the

order required i.e.

(a) Shutters to vertical (non load bearing) faces e.g. column boxes, beam sides, wall forms,

(b) Shutters forming soffits to slabs, horizontal and inclined which carry only light load, e.g. slabs,

roofs, floors and canopies etc.

(c) Soffit shutters carrying heavy load e.g. beam and girder bottoms.

The whole of the formwork should be planned and a definite scheme of operation worked out. In no

circumstances should forms be struck until the concrete reaches strength of at least twice the stress

to which the concrete may be subjected at the time of striking. Where possible the formwork should

be left longer as it would assist curing. Forms should be eased carefully in order to prevent the load

being suddenly transferred to concrete. The period that shall elapse after the concrete has been laid,

before easing and removal of centering and shuttering is undertaken shall be as given in Table 3.6

below:

Table 3.6 Removal of Form Work

Type of formwork

Minimum period before striking formwork

Vertical formwork of Column, Wall and beams

16 – 24 h

Soffit formwork to slabs ( props to be re-fixed immediately after removal of formwork)

3 days

Soffit formwork to beams ( props to be re-fixed immediately after removal of formwork)

7 days

Props to deck slabs spanning upto 4.5 m

7 days

Props to deck slabs spanning over 4.5 m

14 days

Props to beams spanning upto 6m

14 days

Props to beams and arches spanning over 6 m

21 days

Note 1: In case of cantilever slabs and beams, the centering shall remain till structures for counter

acting or bearing down have been erected and have attained sufficient strength.

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Note 2: Proper precautions should be taken to allow for the decrease in the rate of hardening that

occurs with all cements in cold weather.

Note 3: Work damaged through premature or careless removal of forms shall be reconstructed.

3.7 Measurements and Payment

The formwork shall be paid for separately. Measurement shall be taken of the area of shuttering in

contact with the concrete surface.

Dimensions of formwork shall be measured correct to 10mm. The measurements shall be taken

separately under each of the items mentioned in the Pay Item.

No deductions from the shuttering due to the openings/ obstructions shall be made if area of such

openings/obstructions does not exceed 0.1sq.m. Nothing extra shall be paid for forming such

openings.

The rate of formwork includes the cost of planning & design of a safe scaffold system, material,

erection, centering & propping, shuttering and formwork and other materials, tools and plant, labor

required for all the operations described in this section including properly supporting the members as

required until the concrete is cured, set and hardened as required. No separate payment shall be

made for items such as form release agent, connections, ties, provisions for openings and other items

required for the completion of the work unless specified otherwise. The formworks shall be measured

in sqm for payment as per BoQ Item no 14.A.7

3.8 Reinforcement

3.8.1 Description

This work shall consist of furnishing and placing bars of the grade, type and size in accordance with

this specification and the BoQ and in conformity with the requirements shown in the Drawings.

3.8.2 Materials

3.8.2.1 Bar Reinforcement

All high yield steel bars shall be deformed bars with a yield stress not less than 500 N/mm2

and shall

conform to Indian Standard IS:1786 or specification in force that is considered by the Project manager

to apply.

The use of cold twisted bars is not permitted. Steel for all bars shall be produced by open hearth,

basic oxygen or electric arc furnace methods, unless otherwise called for on the Drawings or in

special provisions.

3.8.2.2 Wire Mesh

Wire mesh shall conform to the requirements of Indian Standard IS 1566 [or AASHTO Standard

Specification M 55 -Welded Steel Wire Fabric for Concrete Reinforcement or ASTM A185 / A185M –

07].

3.8.2.3 Binding Wire

Reinforcement binding wire shall be best black annealed mild steel wire, approximately 1.6 mm in

diameter.

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3.8.2.4 Bar Sizes

Metric sizes of steel are shown on the Drawings and shall be used.

3.8.2.5 Ordering Material

The name of the proposed supplier (or names of proposed suppliers) of the reinforcement shall be

submitted as soon as possible to the Project manager for his approval. The Contractor shall also

submit all relevant data on the steel required by the Project Manager, such as breaking strength, yield

strength, characteristics on elongation, chemical composition etc.

Copies of orders placed shall be submitted to the Project manager.

No steel shall be delivered without a manufacturer’s certificate guaranteeing the yield stress, which

shall be submitted to the Project manager.

The steel shall be stored on Site and marked in a way that later enables identification of the steel

corresponding to each certificate.

3.8.2.6 Additional Tests

The Contractor shall cut out steel samples as directed by the Project Manager and these shall be

tested according to the Project manager’s instructions by an approved Testing Institution. Expenses

incurred in connection with cutting out, transporting and testing of the samples shall be paid for by the

Contractor. In general, two samples shall be tested from each batch of a particular size of

reinforcement delivered to the site.

3.9 Construction Methods

3.9.1.1 Protection and Storage

Reinforcement for structures shall be handled and stored in a manner that will prevent bending out of

the desired shape and any accumulation of dirt, oil and paint. When placed in the works it shall be

free from dirt, oil, grease, paint, mill scale and loose or thick rust.

3.9.1.2 Cutting and Bending

Bars shall be cut and bent cold to the dimensions indicated and with equipment and methods

approved by the Project manager.

Stirrups and tie bars shall be bent around a pin having a diameter not less than four times the

minimum thickness of the bar. Bends for other bars, where full tension in the bar may occur, shall be

made around a pin having a diameter not less than twenty times the bar diameter. Hooks shall

conform to IRC:112 - 2011 or as shown in the Drawings.

3.9.1.3 Placing, Supporting and Fastening

All bar reinforcement shall be placed, supported and secured prior to any concreting operations. The

reinforcement shall be checked and approved by the Project manager before pouring of concrete.

Cover blocks required for ensuring that the reinforcement is correctly positioned shall be as small as

possible, consistent with their purpose, of a shape and material acceptable to the Project manager,

and designated so that they will not overturn when the concrete is placed. If made of concrete, the

maximum size of aggregate shall be 6 mm and the mix proportion shall be one part of cement to 2

parts of sand by weight. Wire shall be cast in the block for the purpose of tying it to the reinforcement.

Page 52 of 69


The wire must not be closer than 30 mm from the concrete surface. The use of small stones or wood

blocks shall not be permitted.

The reinforcement shall be held securely in place at the exact position and at the exact spacing as

indicated on the Drawings by the use of wire ties at bar intersections, supports and cover blocks. Wire

ties shall be securely tied and folded so that they do not project beyond the planes formed by the

reinforcing bars. The adequacy of the supports and ties to secure the reinforcement properly shall be

subject to the approval of the Project Manager.

3.9.1.4 Splicing

Reinforcement shall be furnished in the lengths indicated on the Drawings. When the Contractor

wishes to use more splices than are indicated and/or necessary, the Contractor shall furnish Working

Drawings to the Project manager for approval in accordance with the guidelines provided on the

Contract Drawings. If such additional splices are approved, the extra weight occasioned by such

splices shall not be included in the measurement of reinforcement for payment.

All splices for high yield deformed steel bars and mild steel plain steel bars shall have lap lengths as

shown on the Drawings. Lap splices shall generally be located at points of minimum tension in bars.

Except where otherwise shown on the Drawings lap splices shall be made with the bars placed in

contact and securely wired together.

Welding of reinforcing steel shall be done only if detailed on the Drawings or approved in writing by

the Project Manager. Before the Project manager may approve of such welding, the Contractor shall

submit and test any samples as the Project Manager may require and make due allowance for the

time elapsing before results are available.

3.9.1.5 Substitutions

Substitutions of bars shall be permitted only with specific authorization by the Project Manager and at

the expense of the Contractor. If bars are substituted they shall have a cross sectional area equivalent

to the design area, or larger. If substitutions of bars are permitted, the Contractor shall produce

working drawings and reinforcing detailing at his own expense and to the approval of the Project

Manager. Substituted bar must be tested as per requirement of the Project Manager.

3.10 Measurement and Payments

The quantity of reinforcement to be measured under this Section shall be the computed weight in

tonnes of material used and accepted as shown on the Drawings provided that the quantity shall not

include the reinforcement in any item of work for which the basis of payment includes the

reinforcement. In computing the weight to be measured, the theoretical weights of bars of the cross

section shown on the Drawings or authorized shall be used. The weight shall be calculated based on

a constant mass of 0.00785 kg/mm2 per Meter run.

The computed weight shall not include the extra material incurred when bars larger than those

specified are used, or the extra material necessary for splices when bars shorter than those specified

are used with the permission of the Project Manager, or the weight of any devices used to support or

fasten the reinforcement in the correct position including any necessary Chairs for Slab, Pile/Caisson

Caps, Footing or any other structural components. The quantity for the chairs/spacers shown in the

drawings and accounted for in the bar bending schedule are incorporated in the BoQ and shall be

paid for separately at the contract unit price

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However, payment shall be allowed for lap splices not shown when the bars are longer than 12

meters, only one lap splice per every 12 meters will be paid for and where required as per

construction condition and approved by the Project manager.

This work measured as provided above, shall be paid for at the Contract unit price per metric tone

(MT) of reinforcement of the particular type. The payment shall be full compensation for furnishing,

cutting, bending and placing reinforcement of any size and for all labor, binding wire, equipment,

spacer/chair required for placing of reinforcement, tools and incidentals necessary to complete the

work prescribed in this Section. The reinforcement shall be measured in kg as per BoQ Item nos

14.A.13 and 14.A.14

4.0 SECTION 4: MISCELLANEOUS

4.1 Drainage for Structures

4.1.1 Description

This work consists of furnishing and erection of drain outlets on bridge decks and drainage of other

structures including PVC piping, cleaning boxes, catch basins, concrete drains, erosion protection,

inserts, fittings and other incidental parts necessary to provide for further supports of drain pipes in

accordance with the lines, levels, grades, sizes, dimensions and types shown on the Drawings.

4.1.2 Drainage Spouts

4.1.2.1 Scope

This work shall consist of furnishing and fixing in position of drainage spouts and drainage pipes for

bridge decks as per drawing and specification.

4.1.2.2 Fabrication

The drainage assembly shall be fabricated to the dimensions shown on the drawings; all materials

shall be corrosion resistant; steel components shall be of mild steel conforming to IS: 226. The

drainage assembly shall be seam welded for water tightness and then hot-dip galvanized.

4.1.2.3 Placement

The galvanized assembly shall be given two coats of bituminous painting before placement. The

whole assembly shall be placed in true position, lines and levels as shown in the drawing with

necessary cut-out in the shuttering for deck slab and held in place firmly. Where the reinforcements of

the deck are required to be cut, equivalent reinforcements shall be placed at the corners of the

assembly.

4.1.2.4 Finishing

After setting of the deck slab concrete, the shrinkage cracks around the assembly shall be totally

sealed with bituminous sealant as per IS:1834 and the excess sealant trimmed to receive the wearing

coat. After the wearing coat is completed, similar sealant shall be finished to cover at least 50 mm on

the wearing coat surface all round the drainage assembly.

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4.2 Measurements and Payments

The measurement for payment for Drainage spouts shall be number/piece.

The contract unit rate for each drainage spout shall include the cost of all labor, materials tools and

plant required for completing the work as per these Specifications. It shall also include the cost of

providing flow drain pipes with all fixtures up to the point of ground drains wherever shown on the

drawings.

4.3 Open surface drains

4.3.1 General requirements

This Section covers the furnishing of materials and construction of slope stabilization and surface

erosion protection, scour protection and river training works required for bridge protection.

4.3.2 Scope

This item covers construction of lined trapezoidal or box drain of depth 450 mm and clear width of 800

mm including 150mm thick PCC M15:20 base, 300mm thick RRM on both sides in CM 1:4, including

excavation, leveling and disposal of surplus earth within 50m lead.

4.3.3 Excavation

Trenches shall be made along where the drain is to be constructed. The excavation shall be done

exactly to the required profile giving specified slope. The surface shall be levelled to uniform

grade/level and rammed.

For the lined drain the relevant specification for concreting, soling and plastering shall be followed.

The surface of the concrete shall be finished smooth. Any rough surface shall be made smooth by

adding dry mix of cement and sand 1:3 (1 cement: 3 sand) on the surface immediately after

concreting when the concrete is still green. No extra shall be paid for such finishes. All work shall be

carried out as per the drawing and specification or as directed by the Project manager.

The longitudinal slope of the drain must not be less than 3% and it should be uniform to avoid

ponding. The cross slope shall be as per drawing unless otherwise directed by the Project Manager.

All concrete and masonry work shall be thoroughly cured not less than 28 days before water is

allowed to flow in the drain. The clear internal dimension of the drain shall be 800 mm wide and 450

mm deep.


The length shall be measured in running metre correct to 50mm.

The rates shall include the cost of all material, tools & plants and labour involved in the above

operation.

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4.5 HDPE drainage pipes

4.5.1 Scope

This work shall consist of providing HDPE drainage pipes on the deck slab underneath the foot path

slabs (if they exist).

4.5.2 Material

All HDPE pipes shall comply with Indian Standard IS 13592 or ISO D1785:08 Standard Specification

for High Density Polythene pipe (HDPE) Plastic Pipes.

4.5.3 Placement

The pipes shall be placed in true position, lines and levels as shown in the drawing with necessary

cut-out in the shuttering for deck slab and held in place firmly. Where the reinforcements of the deck

are required to be cut, equivalent reinforcements shall be placed around the pipes. The ends of pipes

during construction shall be closed against the intrusion of foreign material.


The drainage pipes shall be measured as number/piece for the shape, length, diameter, wall

thickness etc. shown in the drawings.

HDPE drainage pipes as shown in the drawings and defined in the BoQ, will be paid for at the

Contract unit price.

The price and payment shall constitute full compensation for furnishing all materials as indicated in

the Drawings including delivery, placement, finishing and for all labor, equipment, tools and

incidentals necessary to complete the work.

4.7 Gabion protection works

4.7.1 Scope

This Clause covers the furnishing of materials and construction of gabion works that may be required

to act as buttresses, retaining walls, catch walls, stream or river training structures, check dams within

gullies, or where placed as mattresses, to prevent stream or gully erosion.

4.7.2 Materials

4.7.2.1 Stones

Stones used for filling the gabion boxes or mattresses shall be clean, hard, sound, un-weathered and

angular rock fragments or boulders. The specific gravity of the stone shall be not less than 2.50 and

the stones shall not absorb water more than 5 percent when tested as per IS1124. The length of any

stone shall not exceed three times its thickness. The smallest dimension of any stone shall be at least

twice that of the longer dimension of the mesh of the crate. However smaller size of stones as spalls

shall be allowed for filling voids and its volume including voids shall not be more than 20 percent of

the total volume of the stones.

Before filling any gabion boxes and mattresses the Contractor shall submit representative samples of

the rock he proposes to use in the gabions for approval by the Project Manager. Further

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representative samples shall be submitted for approval each time when there is a change in the type

and strength of the rock.

4.7.2.2 Gabions

Gabions shall consist of steel wire mesh crates. The steel wire shall be mild steel wire complying with

IS 280-197. All wires used in the manufacturing crates and diaphragms, binding and connecting lids

and boxes shall be galvanised with an heavy coating of zinc by an electrolytic or hot dip galvanising

process. The weight of deposition of zinc shall be in accordance with IS 4826-1979. Zinc coating shall

be uniform and be able to withstand minimum number of dips and adhesion test specified in IS 4826-

1979. Tolerance on diameter of wire shall be + 2.5 percent. The tensile strength of gabion wire shall

be between 300 and 550 N/mm2.

The wire shall be woven into a hexagonal mesh with a minimum of 3 twists. All edges of the crates

shall be finished with a selvedge wire at least 3 gauges heavier than the mesh wire. Gabions shall be

manufactured in the standard sizes shown in Table 4.1 with mesh and wire sizes as shown in Table

4.2.

Diaphragms shall be manufactured of the same materials as the parent gabion box and shall have

selvedge wire throughout their perimeter. The number and size of diaphragms to be provided with

each crate shall be as in Table 4.1. All crates shall be supplied with binding and connecting wire of the

gauges shown in Table 4.2 of sufficient quantity to bind all diaphragms and closing edges.

Table 4.1: Standard Size of Wire Mesh Gabions

Dimensions in metres

(Prior to fill)

Number of diaphragms

Dimensions of diaphragms in metres

Volume of crate in cubic metres

1 x 1 x 1 - - 1

1.5 x 1 x 1 1 1 x 1 1.5

2 x 1 x 1 1 1 x 1 2

3 x 1 x 1 2 1 x 1 3

1 x 1 x 0.75 - - 0.75

2 x 1 x 0.75 1 1 x 0.75 1.5

3 x 1 x 0.75 2 1 x 0.75 2.25

1 x 1 x 0.5 - - 0.5

2 x 1 x 0.5 1 1 x 0.5 1

3 x 1 x 0.5 2 1 x 0.5 1.5

1 x 1 x 0.3 - - 0.3

2 x 1 x 0.3 1 1 x 0.3 0.6

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3 x 1 x 0.3 2 1 x 0.3 0.9

Table 4.2: Standard Sizes of Mesh and Wire in Gabions

Mesh

opening mm

Mesh type Thickness of

mesh wire

Thickness of

binding and

connecting wire

Thickness of

selvedge

wire

(DxH) S.W.G. S.W.G. S.W.G.

83x114 80x100 9,10,11 11,12,13 6,7,8

114x128 100x120 10,9 12,11 7,6

The mesh opening shall be as instructed by the Project Manager.

Equivalent diameter in mm

SWG 6 7 8 9 10 11 12 13 14

mm 4.88 4.47 4.06 3.66 3.25 2.95 2.64 2.34 2.03

Construction of Gabions

4.7.2.3 General Requirements

Before filling any gabion boxes and mattresses, the Contractor shall submit samples of gabion boxes

and/or gabion mattresses assembled, erected and filled with stones for approval which, when

approved, shall be retained for reference and comparison with the gabions built as part of the

permanent works. The size, type and location of the samples shall be as directed by the Project

Manager.

Gabion boxes and gabion mattresses shall be assembled, erected and filled with stones in the dry on

prepared surfaces except as may be otherwise approved. Approval for assembling and erecting

gabions in water shall be given only, if in the Project Manager's opinion such a method will produce

work which is otherwise in accordance with the Specification.

4.7.2.4 Preparation of Foundation & Surface for Bedding

The bed on which the gabion boxes or mattresses are to be laid shall be even and conform to the

levels shown on the Drawing. If necessary, cavities between rock protrusions shall be filled with

material similar to that specified for gabion filling.

4.7.2.5 Arrangement of Joints

(a) Walls

In walls, gabion boxes shall be placed such that vertical joints are not continuous, but staggered.

Aprons shall be formed of headers. If more than one unit is required to obtain the necessary width,

units of unequal length shall be used and the joints between them should be staggered.

(b) Channel linings

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In channel linings, gabion box and mattress units shall be laid so that the movement of stone inside

the mesh due to gravity or flow of water is avoided. Hence, on side slopes, units shall be placed with

their internal diaphragms at right angles to the direction of the slope and, on inverts, as far as

possible, at right angles to the direction of flow.

(c) Assembly

Gabion boxes and gabion mattresses shall be assembled on a hard flat surface. After fabrication,

unpacking or unfolding, they shall be stretched out and any kinks shall be removed. Creases shall be

in the correct position for forming the boxes or mattress compartments. The side and end panels shall

be folded into an upright position to form rectangular boxes or compartments. The top corners shall be

joined together with the thick selvedge wires sticking out of the corners of each panel. The tops of all

sides and partitions shall be leveled except as may be appropriate to special units. The sides and end

panels shall be tied together using binding wire of the thickness given in Table 25.2, starting at the top

of the panel by looping the wire through the corner and twisting the wire together. Binding shall

continue by looping the wire through each mesh and around both selvedges with three rounds which

shall be joined tightly together by twisting and the end shall be poked inside the unit. The diaphragms

shall be secured in their correct positions by binding in the same way. The bindings wire shall be fixed

using 250mm long nose fencing pliers or equivalent approved tools.

The gabion boxes and gabion mattresses shall be laid in such a manner that the hinges of the lid will

be on the lower side on slopes and on the outer side in walls.

Where mattresses are laid horizontally hinges shall not be placed on the downstream side as much as

practicable.

(d) Filling

The crates shall be placed in their final position before filling commences. They shall be stretched to

their full dimension and securely pegged to the ground or wired to adjacent gabions before filling. The

vertical corners shall be kept square and to full dimension by inserting a steel bar of at least 20 mm

diameter at each vertical corner, maintaining it in the correct final position throughout the filling

process, and removing it when the crate is full. Before filling commences, the selvedges of the crate

shall be bound to the selvedges of adjacent crates with binding wire. Where crates are being

assembled in position in a wall the binding of the edges of each crate in the assembly process and the

binding together of adjacent crates shall be carried out in the same operation.

Before filling with stone, gabions shall be anchored at one end or side and stretched from the opposite

end or side by inserting temporary bars and levering them forward, The top and bottom shall be kept

stretched by tensioning with tie wires attached to an anchorage or equivalent approved method until

the gabion has been filled. The gabions shall be inspected at this stage but before filling with stone to

ensure that the tie/wiring has been properly carried out and the gabion boxes or gabion mattresses

are not pulling apart. Gabion boxes or gabion mattresses may be tensioned either singly or in the

case of a long straight structure by straining a number of units together using an approved tensioning

system.

The filling shall be carried out by placing individual stones into the gabion by hand in courses in such

a manner that the stones are bedded on each other and bonded as in dry random rubble masonry as

per Clause 1308. No loose stones shall be tipped into the crate and the practice of coursing and

bonding the outer layer and filling the interior with unlaid stones shall not be permitted.

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All 1m deep gabions shall be filled in three equal layers and 0.5m deep gabions in two equal layers.

Horizontal bracing wires made with the same bindings wire as used for tying shall be fixed directly

above each layer of the stone in the compartments, the wires being looped round two adjoining

meshes in each side of the compartment and joined together to form a double tie which shall be

tensioned by wind lassing together to keep the face of the gabions even and free from bulges. Bracing

wires shall be spaced horizontally along and across the gabions at distances not greater than 0.33m.

Where the upper faces of gabion boxes are not covered with further gabions vertical bracing wires

shall be fitted between the top and bottom mesh using two tie wires per square metre of surface.

The ties shall be fixed to the bottom of the units prior to filling and tied down to the lid on completion.

Where a double layer of gabion boxes is used to form an apron both upper and lower layers shall

have vertical tie wires.

(e) Securing Lids

The gabion boxes and mattress compartments shall be over filled by 50mm above their tops to allow

for subsequent settlement. The lids shall then be tied down with binding wire to the tops of all partition

panels. The lids shall be stretched to fit the sides exactly by means of a suitable tool but due care

shall be taken to ensure that the gabions are not so full that the lids are overstretched. The corners

shall be temporarily secured first.

(f) Tolerance

On completion, the crates shall be completely and tightly filled, square, true to dimensions and the line

and level shown on the Drawing. However the tolerance limit permitted in the length, height and width

of the gabion boxes and mattresses as manufactured shall be 3 percent from the ordered size prior

to filling. The tolerances on the wire mesh opening shall be 10% on the nominal dimension 'D'

values as follows:

Mesh type Nominal dimension 'D' values

80x100 83

100x120 114

However, the number of opening per gabion box/mattress shall not be less than the nominal length

divided 'D' on horizontal direction and nominal height divided by 'H' in vertical direction where D and H

are as per Table 4.5.

4.7.2.6 Test & Standard of Acceptance

(1) The gabion wire shall be tested for mass, uniformity and adhesion of zinc coating and tensile

strength of the wire itself. Failure of test results to comply with the specifications shall lead to

the rejection of gabion wires. The test on the samples taken as per Table 15.3 from each lot

of the G.I. wire received at the side of the work shall be carried out in accordance with IS 280-

197 and IS 4826-1979.

Table 15.3: Scale of Sampling and Permissible Number of Defective

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No. of coils in a lot No. of coils randomly

selected for sampling*

Permissible No. of

defective coil

Up to 25 2 0

26-50 3 0

51-150 5 0

151-300 8 1

300 and above 13 1

* One sample per coil shall be tested in all respect.

(2) The stones shall be tested for water absorption. At least 3 set of tests shall be made for every

source of material. The test results shall meet the specified criteria.


Measurement shall be in cubic meters of gabion crates filled with stones and complete in place and

quantity shall be calculated from the dimension of the gabions indicated in the Drawing or ordered by

the Project Manager.

Payment shall be made as per respective contract unit rate which shall be the full and the final

compensation to the Contractor as per Clause 115 to complete the work in accordance with these

Specifications.

4.9 Elastomeric Bridge Bearings

4.9.1 Scope

The purpose of bridge bearing is to spread the load over a pre-determined area of beam above and of

the pier and abutment below, while permitting an adequate amount of elastic and temperature

movements. The degree of sophistication needed in a bearing will depend on the load to be carried

and the number of movements (e.g. translations and rotations) to be allowed for; also for the lateral

forces to be resisted in a direction at right angles to the primary movements.

Design life of bearing is not generally as long as the bridge. Provision must be made for their

replacement as well as their regular inspection. This requires that the bridge can be jacked up and

that bearings can be removed without too much difficulty.

4.9.2 Steel reinforced Elastomeric Bearings

An elastomeric bridge bearing is a device constructed partially or wholly from elastomer. The purpose

of this is to transmit loads and accommodate movements between a bridge superstructure and its

supporting structure. Steel-reinforced elastomeric bearing shall consist of alternate layer of steel

reinforcement and elastomer bonded together. In addition to any internal reinforcement, bearings may

have external steel load plated bonded to either or both the upper or lower elastomer layers.

Bearings should be furnished with dimensions, material properties, elastomer grade and type of

laminates required by the drawings.

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4.9.3 Properties of Elastomer

The raw elastomer shall be either virgin Neoprene (polychloroprene) or virgin natural rubber

(polyisoprene). The elastomer compound shall be classified as being of low temperature grade. The

elastomer shall have a shear modulus between 0.9 and 1.3 MPa. It shall conform to the requirements

of IRC:83 (Part II).

4.9.4 Steel Laminates

Steel laminates used for reinforcement shall be made from rolled mild steel conforming to IS 2062 or

ASTM A36, A570 or equivalent unless otherwise specified by the Project manager. The laminates

shall have a minimum thickness as shown on the drawings. Holes in plates for manufacturing

purposes will not be permitted unless they have been accounted for in the design and shown on the

drawing.

4.9.5 Bond

The vulcanised bond between elastomer and reinforcement shall have a minimum peel strength of 5.2

kN/m. Steel laminated bearings shall develop a minimum peel strength of 6.9 kN/m.

4.9.6 Manufacture

Bearing with steel laminates shall be cast as a unit in a mould and shall be bounded and vulcanised

under heat and pressure. The mould finish shall conform to standard shop practice. The internal steel

laminates shall be sand blasted and cleaned of all surface coatings, rust, mill scale, and dirt before

bonding, and shall be free from sharp edges and burrs. Bearings that are designed to act as a single

unit with a given shape factor must be manufactured as a single unit.

4.9.7 Fabrication Tolerances

Plain pads and laminated bearings shall be built to the specified dimension within the following

tolerances:

Design Thickness 32mm (1¼ in.) or less - - 0, + 3mm

Design Thickness over 32mm - - 0, + 6mm

Overall Horizontal Dimension 914mm (36 in.) or less - - 0, + 6mm

Thickness of Individual Layers of ± 20% of design

Elastomer (Laminated Bearings only) value but not

At any point within the bearings more than ± 3mm

Parallelism with opposite face - 0.005 radian

Top and bottom sides - 0.02 radian

Edge Cover -

Embedded Laminates - - 0, + 3mm

Thickness -

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Top and bottom cover Layer - - 0, the smaller of + 1.5mm and + 20% of

the nominal cover layer

thickness.

4.9.8 Marking and Certifying

The manufacturer shall certify that each bearing satisfies the requirements of the drawings and these

specifications, and shall supply a certified copy of material test results. Each reinforced bearing shall

be marked with indelible ink or flexible paint the bearing identification number, elastomer type and

grade number. The marking shall be on the face that is visible after erection of the bridge.

4.9.9 Testing

i) General

Materials for elastomeric bearings and the finished bearings themselves shall be subjected to the

tests described in the drawings.

ii) Ambient Temperature Tests on the Elastomer

The elastomer used shall at least satisfy the limits prescribed in the AASHTO for durometer hardness,

tensile strength, ultimate elongation, heat resistance, compression set, and ozone resistance. The

bond to the reinforcement, if any, shall also satisfy the requirement of Article 4.9.5 above. The shear

modulus of the material shall be tested at 23°c (73°F) using the apparatus and procedure described in

Annexure A of ASTM D4014. It shall be either equal to or greater than the value shown on the

drawing.

iii) Visual Inspection of the Finished Bearing

Every finished bearing shall be inspected for compliance with dimensional tolerances and for overall

quality of manufacture. In steel reinforced bearings, the edges of the steel shall be protected

everywhere from corrosion.

iv) Short Duration Compression Tests on Bearings

The bearing shall be loaded in compression to 1.5 times the maximum design load. The load shall be

held constant for 5 minutes, removed, and re-applied for another 5 minutes. The bearing shall be

examined visually while under the second loading. If the bulging pattern suggests laminate parallelism

or a layer thickness that is outside the specified tolerances, or poor laminate bond the bearing shall be

rejected. If there are three or more separate surface cracks that are greater than 0.2mm (0.08 in.)

wide and 0.2mm (0.08 in.) deep, the bearing shall be rejected.

v) Long-Duration Compression Tests on Bearings

The bearing shall be loaded in compression to 1.5 times its maximum design load for a minimum

period of 15 hours. If, during the test, the load falls below 1.3 times the maximum design load, the test

duration shall be increased by the period of time for which the load is below this limit. The bearing

shall be examined visually at the end of the test while it is still under load. If the bulging pattern

suggests laminate parallelism or a layer thickness that is outside the specified tolerances or poor

laminate bond the bearing shall be rejected. If there are three or more separate surface cracks that

are greater than 0.2mm (0.08 in.) wide and 0.2mm (0.08 in.) deep, the bearing shall be rejected.

vi) Shear Modulus Tests on Material from Bearings

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The shear modulus of the material in the finished bearing shall be evaluated by testing a specimen cut

from it using the procedure given in annex A of ASTM D4014. If the test is conducted on finished

bearings, the material shear modulus shall be computed from the measured shear stiffness of the

bearing, taking due account of the influence on shear stiffness of bearing geometry and compressive

load.

4.9.10 Installation

Bearings shall be placed on surfaces that are plane to within 1.5mm (1/16 in.) and horizontal to within

0.01 radian. Any lack of parallelism between the top of the bearing and the underside of the girder that

exceeds 0.01 radian shall be corrected by grouting or as otherwise directed by the Project manager.

In order to function correctly the elastomeric bearings must be placed with particular care.

As a general rule, the bearings must be placed on a perfectly plane and horizontal surface. A 30 to 40

mm high mortar pad or for larger height the RC pad is cast onto the base concrete, which must be

previously carefully roughened. The dimensions of the pad must be by 30 to 50 mm larger than those

of the bearing.

When minimum loads are small, it is recommended to glue the bearing to the support with an epoxy

resin.

The bottom face of the pre-cast unit, in contact with the bearing, must be perfectly plane and

horizontal.

For cast-in-situ structures, the bearing is placed on the support and the structure cast on the bearing.

The shuttering surrounding the bearing must be removable at the time of stripping the forms and at

the same time it must be strong enough to resist the weight of concrete. If the base shuttering fails,

the bearing will be partially embedded in the concrete and the distortions hindered. Future lifting of the

structure may become more difficult.


Elastomeric bearing is measured by the total number of complete bearing installed at the specified

bridge location.

Elastomeric bearing measured in accordance with Section 4.10 shall be paid for at the Contract unit

prices for providing bearings in the locations indicated on the Drawings and described in the Bill of

Quantities. Payment shall be full compensation for furnishing and installing all materials, including all

labor, tools, equipment and incidentals necessary to complete the work.

4.11 Movement or Expansion Joints

4.11.1 Scope of Work

The scope of work will include:

i) Preparation of detailed engineering and installation drawings, supply and supervision during fixing of

strip seal/compression seal expansion joints conforming to specifications. The expected

expansion/contraction of the superstructure at the location of expansion joints are shown in relevant

approved drawings.

ii) Design manufacture, providing and seating of expansion joints by the specialized agency and

approved by the Project manager.

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iii) Necessary technical supervision for installation of each and every expansion joint during different

stages of installation including rectification of any deficiency or defect attributable to fixing and

installation will be provided by the manufacturer/supplier. The expansion joint shall be provided for the

full width of bridge including the railing. Leak tightness of all joints shall be ensured.

4.11.2 Specification for Strip Seal Expansion Joint

Expansion joint type described here–after is the “strip seal type”, but alternate designs can be

proposed for the Project manager’s approval.

4.11.2.1 Components:

Strip seal expansion joint shall comprise the following items:

a) Edge beam:

This shall be either extruded or hot rolled steel section or cold rolled cellular steel section with suitable

profile to mechanically lock the swelling element in place throughout the normal movement cycle.

Further the configuration shall be such that the section has a minimum thickness of 10 mm all along

its cross section (flanges and web) the minimum height of the edge beam section shall be 50 mm and

the minimum cross sectional area of the edge beam shall be 1500 sq.mm.

b) Anchorage:

Edge beams shall be anchored to the deck/dirt wall/approach slab by reinforcing bars or bolts or

anchor plates cast in concrete or a combination of anchor plate and reinforcing bars. Anchor bars

studs or bolts shall engage the main structural reinforcement of the deck and in case of anchor plates

or loops, this shall be achieved by passing transverse bars through the loops or plates.

The minimum thickness of anchor plate shall be 12 mm. Total cross sectional area of bar on each

side of the joint shall not be less than 1600 sq.mm per meter length of the joint and the center to

center spacing shall not exceed 250 mm. The ultimate resistance of anchors shall not be less than

600 kN/m in any direction.

4.11.2.2 Material

a. The steel for edge beams shall conform to any of the steel grade corresponding to RST 37-2 or 37-3 (DIN), ASTM A 36 or A 588, CAN/CSA standard G40.21 Grade 300W or equivalent. b. Anchorage steel shall conform to IS: 2062 or equivalent.

c. All steel sections shall be protected against corrosion by hot dip galvanizing or any other approved

anticorrosive coating with a minimum thickness of 100 micron.

d. Chloroprene of strip seal element shall conform to clause 9151.1 of IRC:83 (Part-ll) The properties

of chloroprene shall be as specified in Table 4.11-1

4.11.2.3 Fabrication (Pre-installation)

a. The strip seal joint system and all its component parts including anchorages shall be supplied by

the manufacturer/ system supplier.

b. The width of the gap to cater for movement due to thermal effect, pre stress, shrinkage and creep,

superstructure deformations (if any) and sub-structure deformations (if any) shall be determined and

Page 65 of 69


intimated to the manufacturer depending upon the temperature at which the joint is to be installed, the

gap dimension shall be preset.

Table 4.11-1 Strip Seal Element Specifications

Sl. No Property Specified Value

1 Hardness 63+/- shore A

2 DIN 53505 55+/- Shore A

3 ASTM D (Modified)

4 Tensile strength Min. 11 MPa

5 DIN 53504 Min. 13.8 MPa

6 ASTM D412

7 Elongation at fracture Min. 350 per cent

8 DIN 53504 Min. 250 per cent

9 ASTM D412

10 Tear Propagation strength Min. 10 N/mm

11 Longitudinal Min. 10N/mm

12 Transverse Min. 25 per cent

13 Shock elasticity Min 220 Cu. mm

14 Abrasion

15 Residual compressive strain (22/70 deg C/30 per cent)

Aging in hot air (14 days/70 degC)

Max. 28 per cent

16 Change in hardness Max. +7 Shore A

17 Change in tensile strength Max. -20 per cent

18 Change in elongation at fracture -20 per cent

19 Aging in ozone (24h/50pphm/25 deg per cent

elongation)

No cracks

20 Swelling behaviour in oil (168h/28 deg/C)

21 ASTM Oil No. 1 Max. +5 per cent

22 Volume Change Max. -20 Shore A

23 Change in hardness Max. -35 deg C

24 ASTM Oil No. 3 Max. +25 per cent

25 Volume change Max. -25 Shore A

26 Change in hardness Max. -35 deg C

27 Cold Hardening Point

c. Each strip seal expansion joint system shall be fabricated as a single entity unless stage

construction or excessive length prohibits monolithic fabrication. It shall fit the full width of the

structure as indicated on the approved drawing. The system shall be pre-set by the manufacturer prior

to transportation. Presetting shall be done in accordance with the joint opening indicated on the

drawing.

d. The finally assembled joint shall them be clamped and transported to the work site.

4.11.2.4 Handling and Storage

a. For transportation and storage, auxiliary brackets shall be provided to hold the joint assembly

together.

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b. The manufacture/ supplier shall supply either directly to the Project manager or to the Bridge

Contractor all the materials of strip seal joints including sealants and all other accessories for the

effective installation of the jointing.

c. Expansion joint material shall be handled with care. It shall be stored under cover on suitable

lumber padding.

4.11.2.5 Supply/ Installation

Components of expansion joint such as edge beam and strip seal shall be arranged by the contractor

by procuring the same from reputed approved manufacturer to ensure quality and performance.

Contractor shall furnish a warranty of trouble free performance for at least ten years and free

rectification of defects / replacement, if any, during this period.

The joints shall be installed in compliance to the manufacturer’s instructions for installation.

Taking the width of gap for movement of the joint into account the dimensions of the recess in the

decking shall be established in accordance with the drawings or design data of the manufacturer. The

surfaces of the recess shall be thoroughly cleaned and all dirt and debris removed. The exposed

reinforcement shall be suitably adjusted to permit unobstructed lowering of the joint into the recess.

The recess shall be shuttered in such a way that dimensions in the joint drawing are maintained. The

formwork shall be rigid and firm.

Immediately prior to placing the joint, the presetting shall be inspected. Should the actual temperature

of the structure be different from the temperature provided for presetting, correction of the presetting

shall be done. After adjustment the brackets shall be tightened again.

The joint shall be lowered in a pre-determined position. Following placement of the joint in the

prepared recess, the joint shall be leveled and finally aligned and the anchorage steel on one side of

the joint welded to the exposed reinforcement bars of the structure. Upon completion, the same

procedure shall be followed for the other side of the joint. With the expansion joint finally held at both

sides, the auxiliary brackets shall be released allowing the joint to take up the movement of the

structure.

High quality concrete shall then be filled into the recess. The packing concrete must feature low

shrinkage and have the same strength as that of the superstructure but in any case not less than M30

grade good compaction and careful curing of concrete is particularly important.

After the concrete has cured, the movable installation brackets and shuttering still in place shall be

removed.

The neoprene seal shall be field installed in continuous length spanning the entire roadway width. To

ensure proper fit of seal and enhance the ease of installation dirt, spatter or standing water shall be

removed from the steel cavity using a brush, scrapper or compressed air. The seal shall be installed

without any damage to the seal by suitable hand method or machine tools.

The deck surfacing shall be finished flush with the top of the steel sections, the horizontal leg of the

edge beam shall be cleaned beforehand. It is particularly important to ensure thorough and careful

compaction of the surfacing in order to prevent any premature depression forming in it.

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4.11.2.6 Acceptance criteria

a. All steel elements shall be finished with corrosion protection system

b. For neoprene seal, the acceptance test shall conform to the requirements stipulated in Table

4.11-1. The manufacturer/ supplier shall produce a test certificate accordingly, conducted in a

recognized laboratory, in India or abroad.

c. The manufacturer shall produce test certificates indicating that anchorage system had been tested

in recognized laboratory to determine optimum configuration of anchorage assembly under dynamic

loading.

d. Prior to acceptance 25 percent of the completed and installed joints, subject to a minimum of one

joint, shall be subjected to water tightness test. Water shall be continuously pounded along the entire

length for a minimum period of 4 hours for a depth of 25mm above the highest point of deck. The

width of ponding shall be at least 50mm beyond the anchorage block of the joint on either side. The

depth of water shall not fall below 25mm anytime during the test. A close inspection of the underside

of the joint shall not reveal any leakage.

e. As strip seal type of joint is specialized in nature, generally of the proprietary type, the manufacturer

shall be required to produce evidence of satisfactory performance of this type of joint.

4.11.2.7 Test and standards or acceptance:

The materials shall be tested in accordance with these specifications and shall meet the prescribed

criteria. The manufacturer/supplier shall furnish the requisite certificates from the recognized

laboratory in India or abroad.


Expansion joints shall be measured by the linear Meter of complete joint installed, measurement

being along a straight line from base to top of a wall or one side of a slab to the other, etc. The

measured length may therefore include a sealant length of over twice this value if several faces of the

concrete are sealed.

Expansion joints measured in accordance with Section 4.12 shall be paid for at the Contract unit

prices for providing joints in the locations indicated on the Drawings and described in the Bill of

Quantities. Payment shall be full compensation for furnishing and installing all materials, including all

labor, tools, equipment and incidentals necessary to complete the work.

5.0 SECTION 5: DAY WORKS

5.1 General

Work shall not be executed on a Daywork basis except by written order of the Project Manager. Bidders shall enter basic rates for Daywork items in the Schedules, which rates shall apply to any quantity of Daywork ordered by the Project Manager. Nominal quantities have been indicated against each item of Daywork, and the bidders must provide competitive rates for each item.

5.2 Dayworks Labour

In calculating payments due to the Contractor for the execution of Daywork, the hours for labour will be reckoned from the time of arrival of the labour at the job site to execute the particular item of Daywork to the time of return to the original place of departure, but excluding meal breaks and rest

Page 68 of 69


periods. Only the time of classes of labour directly doing work ordered by the Project Manager and for which they are competent to perform will be measured. The time of gangers (charge hands) actually doing work with the gangs will also be measured but not the time of foremen or other supervisory personnel.

The Contractor shall be entitled to payment in respect of the total time that labor is employed on Daywork, calculated at the rates quoted in the Daywork of BOQ. The rates for labor shall be deemed to cover all costs to the Contractor including (but not limited to) the amount of wages paid to such labor, transportation time, overtime, subsistence allowances, and any sums paid to or on behalf of such labor for social benefits in accordance with law of Kingdom of Bhutan, as well as Contractor's profit, overheads, superintendence, liabilities and insurance and allowance to labor, timekeeping and clerical and office work, the use of consumable stores, water, lighting and power; the use and repair of staging, scaffoldings, workshops and stores, portable power tools; supervision by the Contractor's staff, foremen and other supervisory personnel; and charges incidental to the foregoing. The rates shall be stated in the local currency.

5.3 Dayworks Materials

The Contractor shall be entitled to payment in respect of materials used for Daywork (except for materials for which the cost is included in the percentage addition to labour costs as detailed heretofore), at the rates entered by him in the Materials section of Daywork, and shall be deemed to include overhead charges and profit as follows;

(a) the rates for materials shall be calculated on the basis of the invoiced price, freight,

insurance, handling expenses, damage, losses, etc., and shall provide for delivery to store for stockpiling at the Site. The rates shall be stated in local currency.

(b) the cost of hauling materials for use on work ordered to be carried out as Daywork from the

store or stockpile on the Site to the place where it is to be used will be paid in accordance with the terms for labor and Constructional Plant in this Schedule.

5.4 Dayworks Plant

The Contractor shall be entitled to payments in respect of Construction Equipment already on Site and employed on Dayworks at the rental rates entered by him in the Construction Plant section of Dayworks. The said rates shall be deemed to include due and complete allowance for depreciation, interest, indemnity, and insurance, repairs, maintenance, supplies, fuel, lubricants, and other consumables, cost of drivers, operation and assistants and all overhead, profit, and administrative costs related to the use of such equipment.

In calculating the payment due to the Contractor for Construction Plants employed on Dayworks, only the actual number of working hours will be eligible for payment.

The rental rates for Constructional Plant employed on Dayworks shall be stated in local currency.