Vol II_Book I_CH1_G_Guidelines of Design Principle and Spec..

7/29/2019 Vol II_Book I_CH1_G_Guidelines of Design Principle and Spec..

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APPDCLTechnical Specification

For

Sea Water Intake System

Sri Damodaram Sanjeevaiah

Thermal Power Station

2X800 MW

Tender DocumentVolume II_Book I_Chapter 1 Page 1 of 52 WAPCOS LIMITED

CHAPTER - 1

GUIDELINES OF DESIGN PRINCIPLE AND SPECIFICATIONS FOR MATERIALS

AND WORKS

1.1 INTRODUCTION

This chapter provides broad guidelines for designing the different components

of the work and also covers the specifications for material used for civil,

structural building and architectural work. The bidder has to follow the relevant

Indian Standard specification while designing the different components of the

works. Wherever Indian Standard specifications are not available the bidder

has to quote proper authority (or) code for the assumption made and method

adopted and the bidder has to enclose the authority (or) code. Similarly for the

procurement of material used for testing of materials unless specified in the

tender the relevant provision of the appropriate bureau of Indian Standard

(BIS) shall apply for all materials and workmanship. Where the relevant BIS

do not exists; the latest version of the relevant British Standard specification

(or) standard of the American society for testing material shall apply.

1.2 SCOPE OF WORKS

The work contemplated covers the design, manufacture, assembly, testing,

supply, construction of shore based intake through open channel with two

groynes, Stone protection works for groynes, dredging of offshore channel

construction of approach channel (onshore and offshore channel),

construction of desilting basin, Construction of forebay, Construction of pump

house including sump, Laying and assembly of Intake and Outfall pipeline,

Construction of approach road of single lane (Sectional drawing enclosed)

along the pipeline route upto pump house, Construction of MCC room,

chlorination room, Outfall Structure including diffuser, civil, structural,

Mechanical, Electrical, Control & Instrumentation and architectural works as

specified / required for safe and trouble-free operation of Sea water Intake and

Outfall system for 2 X 800 MW Units and for future 1 X 800 MW Unit of

SDSTPS at Nellore, Andhra Pradesh, India, including One (1) year Operation

and maintenance of the commissioned plant with personnel, spares &

consumables and imparting training to APPDCL/APGENCO staff on O&M of


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entire system. The major scope of works involved are the following but not

limited to the same for civil and mechanical works of sea water intake and

outfall system.

Design, Construction of groynes, offshore channel of suitable

size including stone protection works for groynes, dredging of

offshore channel etc.

Design, construction of onshore channel, desilting basin.

Design, construction of forebay including counterfort retaining

wall/RCC Diaphragm wall etc.

Design, construction of Pump house including sump etc.

Design, supply & installation of three (3) numbers Vertical

Turbine pumps with all necessary electrical, mechanical

accessories and provision of two (2) numbers future pumps

Design, procuring, jointing and laying of factory made 2200 mm

diameter and minimum 16 mm thick delivery/intake pipeline

including 2 mm thick PU coating from pump house to terminal

point (TP1) inside the plant with all necessary butterfly valves,

air valves, sluice valves, thrust block ,anchor blocks, valve

chambers, expansion joints etc.

Design, procuring, jointing and laying of factory made 1800 mm

diameter and minimum 14 mm thick Return/Outfall pipeline

including 2 mm thick PU coating from terminal point (TP1) to

diffuser point as specified with necessary butterfly valves, air

valves, sluice valves, thrust block ,anchor blocks, valve

chambers, expansion joints etc.

Design, construction of approach road from plant boundary to

pump house along the pipeline route.

Design, supply & installation of three (3) nos. traveling water

screens, coarse screens.

Design, supply & installation of six (6) nos stop log gates and

provision of two (2) numbers future requirement.

Design, supply & installation of Cranes and Hoists as per

requirement.


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Design, supply & installation of Electro chlorination system for

sea water to avoid biofouling in Intake pipeline with all necessary

accessories etc.

Surface preparation and necessary corrosion resistance painting

for all equipment, piping, valves, structures, buildings, tanks,

walls, platforms etc.

One (1) year Operation and maintenance of the commissioned

plant with personnel, spares & consumables and imparting

training to APPDCL/APGENCO staff on O&M of system.

Scope of works specified above is tentative and Bidder has to execute

complete works for satisfactory functioning of entire Sea water intake & Outfall

System. The Bidder shall quote for the Base scheme and can suggest

alternative options with separate price which will not be considered for

evaluation.

The preliminary geotechnical investigation, hydrographic survey, topographic

survey and oceanographic studies were conducted by the purchaser and

preliminary report is available with Purchaser and will be furnished to the

successful bidder for reference. However for detailed engineering and

construction Bidder has to carry out necessary geotechnical investigation,

hydrographic survey, topographic survey and oceanographic studies etc. as

required.

Any discrepancies or lack of inconsistency data found at a later date in

Purchasers investigation shall not form the basis of any extra claim or time

extension. Bidder shall take special care to assess exact nature and quantum

of work involved both on shore and off shore area.

The system design & construction shall be proven to meet all functional

requirements and perform accurately and safely under the prevailing

environmental and operating conditions without undue heating, vibration,

wear, corrosion, aging, malfunction or other operating problems.

All equipment, materials and instruments shall be supplied from reputed

manufacturer and approved vendors of APPDCL/APGENCO and shall

conform to relevant latest national / international standards.


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The description of work given in the document is for broad understanding of

the nature of the work. The bidder should acquaint himself with nature of

work to be performed for continuous trouble-free operation.

The details of civil, structural, architectural work involved that require design,

drawing, material for construction are given below.

Design and construction of groynes, dredging of Intake channel in the

sea and desilting basin with proper embedment and other protective

works ,concrete lining from onshore open channel to forebay, including

Mechanical Components

Design of Intake Pump House and associated Switchgear& control room

and Electro Chlorination Plant room.

Laying of partly underground, partly over ground and over Buckingham

canal the intake pipeline up to the terminal point (TP1) which is at a

distance of around 5.3 km from the proposed pump House.

Laying of partly underground, partly over ground and over Buckingham

canal the return flow water pipeline on land and off shore submarine pipe

up to a Diffuser section as specified.

The work to be performed shall also include all labour, consumables,

equipment, temporary works, temporary storage sheds, temporary labour and

staff colony, temporary site offices, construction plant, fuel supply, power,

transportation including making arrangement of power where required and all

incidental items not shown or specified but reasonably implied or necessary for

the completion of civil works, all in strict accordance with the specifications,

Latest codal requirements and including revisions and amendments there to as

may be required during the execution of the work.All materials including cement, reinforcement steel, structural steel, etc. shall be

arranged / procured by the Bidder.

The work shall include setting up a complete testing laboratory in the field to

carry out all relevant tests required for the civil works.

The Contractor shall setup a quality control laboratory with all facilities to carry

out the testing of all construction materials and field quality tests as per field

quality plan (FQP)/ Specifications/relevant IS Codes. The contractor shall

provide sufficient qualified and competent manpower for carrying out Lab testing


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and field quality control. The Contractor shall provide all facilities to carry out the

test desired by the PURCHASER. If the contractor does not have facility for

some tests, these tests should be got done from reputed third party Labs. All

costs for testing will be borne by the Contractor for Quality Assurance (QA) &

Quality Control (QC). The test certificates/lab reports of different construction

materials shall be submitted by the contractor for PURCHASERs review and

approval before incorporating the material in the work. The contractor shall also

submit the Test reports of various tests of the works to the PURCHASER for

review/Approval.

All the documents (Soft & Hard Copy) shall be properly maintained and easily

retrievable.

The Contractor shall submit field quality plan (FQP) 15 days in advance for

approval of the PURCHASER before commencement of the works.

The work shall be carried out in accordance with the design / drawings to be

developed by the Bidder and approved by the PURCHASER. For all onshore

and offshore constructions and foundations, etc., necessary layout details are to

be developed by the Bidder keeping in view the statutory & functional

requirements of the system & facilities sufficient space and access shall be

provided in the layout. Certain minimum requirements are indicated in this

specification for guidance purpose only. However, the Bidders offer shall cover

the complete requirements as per the best prevailing practices and to the

complete satisfaction of the PURCHASER.

All the standards and other technical requirements as covered in this

specification and relevant code of practice shall be strictly adhered to by the

Bidder in order to achieve the quality of work.

The Bidder should fully apprise himself of the prevailing conditions at the

proposed site, meteorological conditions like climate, rainfall, relative humidity,

wind, storm and cyclones, visibility, oceanographic conditions, local conditions,

site specific parameters and shall include for all such conditions, contingent

measures in the bid, including those which may not have been specifically

brought out in the specifications. The PURCHASER has carried out

environmental parameter by engaging outside agency and the same may be

availed if required for reference.


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The bidder has to carry out all survey works such as bathymetry, topography

and hydrographic survey in order to assess the bed profile of the sea and also

to assess the quantum of dredging and also to decide the depth of founding for

structural component.

1.3 SUBMISSIONS OF DOCUMENTS

The following documents are to be submitted for the approval of the

PURCHASER, prior to commencement of fabrication. All drawings shall be of

standard sizes (Metric System) and shall be made on AutoCAD format. Editable

soft copies of Design calculations and design basis in original format and

drawings in AutoCAD format shall be submitted. This will be addition to the hard

copies that have to be submitted for the above items.

Layout drawing of various facilities at onshore and offshore location, all

pipeline routing drawings with coordinates, showing roads, bridges,

culverts etc.

Drawing showing underground facilities with co-ordinates of these

facilities like buried pipes, buried cable, trenches, ducts, sewer, drains,

sumps, pits, culverts, foundations, etc. along pipe routes.

Architectural floor plans, elevations, cross-sections and perspective view

of all buildings.

Site leveling, area filling drawings indicating final grade levels of various

areas along with survey drawings indicating the natural contours and

spot levels of the natural ground, permanent features, etc.

Basis of design of all buildings, facilities, services and structures. The

Contractor shall get the design basis report approved by

PURCHASER/Consultant prior to undertaking any detailed engineering

works.

Design calculations and drawings for foundations / sub-structure and

superstructure of all buildings including pump houses and other all

structures.

Bidders reports on Hydraulic model studies on Intake Pump sump

including forebay Numerical model studies on discharge water

recirculation, quantity of littoral drift, hydrodynamics and sedimentation


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and Flume studies for gryones trunk section and round head section

from reputed laboratory like IIT/CWPRS.

Drawings of all architectural works including finish schedule, colour

scheme (Both internal and external), doors & windows, flooring and false

ceiling, etc.

Design calculations and drawings for plumbing and building drainage.

Write-up on various statutory requirements and their compliance for

various buildings and facilities.

Copy of all studies / investigations report carried out by the Bidder as per

scope.

Fabrication drawings all structural steel works (only for reference) &design calculations for important joint connections.

Marking scheme identifying the equipment / pump lay down areas.

All other designs, details / drawings or any other submission as indicated

elsewhere in this specification and as required by the PURCHASER.

Details of corrosion protection and anti-bio-fouling measures for all

structures.

All construction drawings shall include total quantity of concrete (grade

wise), reinforcement steel (diameter wise) and structural steel (section

wise).

Type of dredger proposed to be engaged for dredging the sea bed to

facilitate for intake channel.

Report on the detail methodology for laying and anchoring offshore

outfall pipeline.

Report on the detailed methodology of construction of onshore pump

house, forebay, desilting Basin, open channel and de-watering.

Report on design and laying of onshore and offshore pipelines.

1.4 LOCATION OF WORK

1.4.1 LOCATION OF SHORE BASED INTAKE

A tentative location and dimensions of Groynes has been shown in the

tender drawing for drawing intake sea water. These drawings of groynes are

for guidelines only; Bidder shall design groynes section as per requirement.

The Intake channel will be protected by groynes to protect from siltation.


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These groynes are rubble mound type structure with approximate length of

185m. The intake channel of 30 m width and dredged up to -3.0 m CD contour

in between two gryones one on south side and other on north side and sea

water will be carried out on land by open channel excavated up to -3.0 m

below CD and bottom width will be 5 m. This channel will be connected to

desilting basin of bottom width 12m and excavated up to -4.0 m below CD and

stone protection also provide to two groynes from scouring.

1.4.2 INTAKE PUMP HOUSE AND FOREBAY

Pump house structure shall be founded at a location shown tentatively at the

tender drawing. A forebay will be provided in front of pump house to receive

water from open channel. Functional requirement of the pump house is toreceive water and pumping it to main plant area through intake pipe line.

A maintenance bay shall be provided with heavy vehicle entry facilities for

erection and maintenance. A screen and gate handling bay shall be provided

in the pump house for storing gates/screens whenever they are not in use.

The storage bay shall be provided with crane access for hauling gates/screen

and also with structures supporting and stacking them for.

The foundation of Pump house including sump portion shall be designed on

pile keeping in view of the soil conditions. The super structure of the pump

house shall comprise of RCC design mix, construction the pump house will be

provided with heavy duty EOT crane travelling over crane runway girders

spanning between brackets. Suitable access and platform / walkway shall be

provided for crane operation. The side cladding shall be of brick wall laid, and

jointed in cement mortar as per specification. The roof shall have parapet and

water proofing as per specification. The ground floor shall have heavy-duty

floor finish. Adequate door /windows/ ventilators shall be provided as per

specification. Vertical turbine pumps will be placed on RCC pump operating

floor. Suitable hatch shall be kept on the floor to access the pump sumps by

ladder.

Forebay is located on the shore line side of the pump house as shown in

tender drawings. The fore bay receives seawater through an onshore

channel. The side walls and base slab shall be of RCC and foundation shall

be based on soil conditions, Hand rails all along the side walls as per


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specification shall be provided for safety. The layout of forebay shall conform

to the stipulation of Manual of Hydraulic Institute and BHRA.

Annexed to the pump house there will be chlorination plant room, Electrical

switchgear and control room. The building will be a RCC framed structure

with brick wall side cladding. Minimum clear height under the roof of building

shall be 4.50 m or more if required for adequate clearance. The building shall

have toilet facilities. Adequate door/window / ventilators / louvers shall be

provided in the above building. The MCC room and Chlorination room shall

have vitrified tiles flooring with provision AC and false ceiling.

1.4.3 INTAKE CHANNEL / OFFSHORE CHANNEL

Intake / Offshore channel is proposed to be provided at sea side and it is to beprotected with two groynes. Intake channel will have 30 m width and dredged

upto -3.0 m contour below CD. This channel will be extended up to 180 m in

to the sea from High Tide Line and will be taken through open channel or

onshore channel on land and connected to desilting basin.

A desilting basin will be formed at appropriate location before Pump house

as shown in the tender drawing. Size and depth of basin will be ascertained

by hydraulic model study. Sludge removal facilities will provided in the

desilting basin so that it can be cleaned without interrupting the water flow to

the pump house or generation at power plant.

[

1.4.4 BRIDGE OVER BUCKINGHAM CANAL WITH APPROACH RAMP &CROSS OVER BRIDGE

The cross over structure for laying / taking the Intake & Outfall pipelines and

roadway wherever required shall be RCC of mix design concrete. The

minimum height shall 8 m keeping in view of navigation under the bridge. The

width of bridge shall fix considering diameter of Intake and outfall pipeline,

sufficient space for inspection and walking and approach road etc. The

foundation of bridge shall be designed on pile keeping view of soil conditions

for further details refer drawing enclosed

1.4.5 LAYING OF INTAKE PIPELINE

Intake pipeline from Pump house shall be laid up to the terminal point (TP1)

and these pipeline is partially over ground and partially buried below ground


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level and minimum 1m to be maintained between top of pipeline and existing

RL of ground. The work shall include construction of valve chambers/manhole

chambers/sludge pits and sub base layer etc. The Intake pipeline shall be

anchored properly for the exposed pipeline and wherever necessary at bend

and level difference shall be provided with thrust blocks. The backfilling shall

be done by the excavated soil to the maximum extent possible and it shall be

properly consolidated / compacted.

1.4.6 LAYING OF RETURN FLOW / OUTFALL PIPELINE UP TO DIFFUSERPOIN

A tentative location of return flow / Outfall pipeline is shown in the tender

drawing. The outfall pipeline is to be laid partially over ground and partially

buried below ground level and minimum 1m to be maintained between top of

pipeline and existing RL of ground and to be taken upto the diffuser point in

sea as specified and thereafter it shall be taken by suitable means depending

upon the sea bed level.

The outfall pipeline shall terminate at the diffuser section, designed to

promote rapid mixing and dilution with surrounding sea water. A multi port

diffuser system shall discharge the reject water into the sea. The diffuser portshall consist of riser pipes projecting up from the diffuser pipeline that is

buried beneath the sea and shall be properly anchored. The diffuser head will

be encased in concrete for protection against ship anchors and suitable case

should be also provided. The diffuser structure shall be firmly founded in the

seabed below the scour depth. Additional concrete collar blocks shall be

placed over the diffuser to increase the stability. Marker buoys shall be

located around the diffuser head if needed.

The design and construction of offshore concrete and other type of structure

like diffuser shall conform to the followings

Recommendation for the design and construction of concrete marine

structures

Relevant Indian Codes of practices IS 4651 Part I to Part V, IS 9556, 9527

and other latest codes etc.

1.5 GEOTECHNICAL INVESTIGATION AND FOUNDATION SYSTEM


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The Bidder shall carry out his own geotechnical investigation in all works before

commencing detailed design and working drawings for finding out the allowable

bearing pressures, expected settlements, type of foundations, etc. as per the

relevant Bureau of Indian Standard. The soil investigation report shall be

submitted to the PURCHASER for approval and the approved report shall

become the basis for design of sub-structure. Approval of the PURCHASER

shall in no way relieve the contractor of his sole responsibility in regard to

stability and safety of the structure.

1.6 REQUIREMENT OF FOUNDATIONS DESIGN

All foundation system shall be as per the recommendation of soil investigation

report furnished by Bidder. The foundation system will comprise both Pilefoundations as well as isolated / strip / raft foundations depending on Intensity

of loading and settlement criteria and based on the bearing capacity of the

soil.

For design of foundations, net allowable bearing capacity in different strata

shall be considered based on the soil investigation report.

The foundation shall be designed for the maximum bending moment that

arrived from various combinations of loading.

In case of presence of high water table, necessary dewatering shall have to

be made in order to carry out the excavation without any side collapse. In

case, deep well point system is required, the same shall also be provided. In

addition to above, at certain places sheet piling to support sides of

excavations may also be required. Scheme for dewatering and design with all

computations and back-up data of dewatering and sheet piling shall be

submitted for PURCHASERs information.

The founding level shall be decided as per functional requirement. The bottom

of excavation shall be properly compacted prior to casting of bottom slab of

trenches. The depth of foundation shall be fixed based on Safe bearing

capacity of soil.

Backfilling around foundations shall be carried out with excavated materials in

layers not exceeding 20 cm thickness and each layer shall be compacted to

95% standard proctor density for cohesive soil and to 85% of relative density

for non-cohesive soils.


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For open foundations, the total permissible settlement and differential

settlement will be as per latest code of practice and from functional

requirements whichever is more stringent. However total settlements of

foundation resting on soil will be restricted to following:

a) Isolated/ Strip footing of width up to 6.0m : 25 mm

b) Footing of width greater than 6.0m (raft) : 50 mm

1.6.1 CODES AND STANDARDS

a) Internationally accepted design Codes and Standards where Indian

Codes are not available and which are equivalent to Indian Standards.

b) National Building Code of India.

c) "Accepted Standards" and "Good Practice" listed in the appendix to

National Building Code of India.

d) IS-1200: Method of measurement of Building and Civil Engineering

Works.

e) IS-1256: Code of Practice for Building By laws.

f) IS-456 : Code of Practice for Plain and reinforced concrete.

In addition to the above, the stipulation in the relevant code for each item of

work shall be followed.

1.6.2 FOUNDATIONS

a) IS-1904 : Code of practice for design and construction of

foundations & soils.

b) IS-2950 : Code of practice for design and construction of raft

foundations.

c) IS-2974 : Code of practice for design and construction of

Machine foundations (all parts).

d) IS 2911 : Code of practice for Design and Construction of Pile

Foundation. (All parts)

1.6.3 LOADING

a) IS-875 : Code of practice for design loads for buildings and

structures - loading standards (all parts).

b) IRC 6 : I.R.C loading classification.


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1.6.4 ROOF AND FLOORING

a) IS-2204 : Code of practice for construction of reinforced

concrete shell roof.

b) IS-3201 : Criteria for the design and construction of precast

concrete trusses and purlins.

c) IS-809 : Rubber flooring materials for general purposes.

e) IS-1195 : Bitumen mastic for flooring.

f) IS-1196 : Code of practice for laying bitumen mastic flooring.

h) IS-1237 : Cement concrete flooring tiles.

i) IS-1443 : Code of practice for laying and finishing of cement

concrete flooring tiles.

j) IS-2114 : Code of practice for laying in situ terrazzo floor finish.

k) IS-2571 : Code of practice for laying in situ cement concrete

flooring.

l) IS-5491 : Code of practice for laying in situ granolithic concrete

floor topping.

m) IS-5766 : Code of practice for laying burnt clay brick flooring.

n) IS-1197 : Code of practice for laying of rubber floors.

o) IS-2441 : Code of practice for fixing ceiling coverings.

1.6.5 WATER PROOFING

a) IS-1322 : Bitumen felts for waterproofing and damp proofing.

b) IS-1346 : Code of practice for waterproofing of roofs with bitumen

felts.

c) IS-1609 : Code of practice for laying damp proof treatment using

bituminous felts.

d) IS-3036 : Code of practice for laying lime concrete for a

waterproofed roof finish.

e) IS-3037 : Bitumen mastic for use in waterproofing of roofs.


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f) IS-3067 : Code of practice for general design, details and

preparatory work for damp proofing and water proofing

of buildings.

g) IS-3384 : Bitumen primer for use in water proofing and damp

proofing.

h) IS-4365 : Code of practice for application of bitumen mastic for

waterproofing of roofs.

1.6.6 EARTHQUAKE RESISTANT DESIGN

a) IS-1893 : Criteria for earthquake resistant design of

structures.

b) IS-4326 : Code of practice for earthquake resistant design

1.6.7 STRUCTURAL STEELWORK

a) IS-800 : Code of practice for general construction in steel.

Part-I: Load and permissible stresses.

Part-II: Fabrication, Galvanising, Inspection and

Packing.

c) IS-806 : Code of practice for use of steel tubes in general

building construction.

d) IS-808 : Rolled steel beams, channels and angle sections.

e) IS-813 : Scheme of symbols for welding.

f) IS-814 : Covered electrodes for manual metal arc welding of

carbon and carbon manganese steel.

g) IS-816 : Code of practice for use of metal arc welding for

general construction in mild steel.

h) IS-817 : Code of practice for training and testing of metal arc

welders.

i) IS-818 : Code of practice for safety and health requirements in

electric and gas welding and cutting operation.

j) IS-819 : Code of practice for Resistance spot welding for light

assemblies in Mild Steel.

k) IS-919 : Recommendations for limits and fits for engineering.


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l) IS-1024 : Code of practice for use of welding in Bridges and

Structures subjected to Dynamic loading.

m) IS-1161 : Steel tubes for structural purposes.

n) IS-1182 : Recommended practice for Radiographic Examinationof Fusion Welded Butt joints in steel plates.

1.7 ENVIRONMENTAL PROTECTION

Chapter on Corporate Responsibility for Environmental Protection (CREP)

published in Gazette of India dated 27.08.2003.

1.8 LOADING ON STRUCTURES AND FOUNDATIONS

1.8.1 GENERAL

All structures and buildings including Pump House, Water Retaining

structures, desilting basin and various other works including Site leveling,

Approach roads, Drains, Sewers, etc., are covered in this specification. In

case of marine structures, environmental forces due to wave, current &

sediment loads, etc. shall also be considered and latest design standard

practices shall be followed.

Structures shall be designed for the most critical combinations of loads, as

stipulated in IS 456 2000 and other latest code as applicable for marinestructure.

1.8.2 DEAD LOADS

Dead loads shall include the weight of structure complete with finishes,

fixtures and partitions.

1.8.3 IMPOSED LOADS

The imposed load to be considered for the design of various structures shall

be based on IS 875 all parts of latest edition and IS 456-2000 with latest

editions.

In addition to the imposed load as prescribed in the relevant IS equipment

load, erection, operation and maintenance load shall be considered for

designing the structure.

1.8.4 EQUIPMENT LOADS

Loads of all equipment like Pumps, Pump Motor, Cooling Equipment,

Electrical Control and Relay Panels, Cable load, Pipe load (static and

dynamic), stop log gates, trash racks, traveling water screen, Tanks etc., shall


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be considered over and above the imposed loads as per the manufacturers

recommendations. Loads due to thermal expansion and hydraulic thrust of

pipes shall also be considered.

1.8.5 CRANE LOADSFor crane loads, an impact factor of 25% and lateral crane surge of 10% (of

lifted weight + trolley weight) shall be considered in the analysis of frame

according to the provisions of IS : 875. The longitudinal crane surge shall be

5% of the static wheel load.

1.8.6 WIND LOADS (WL)

Wind loading will be in accordance with latest edition of Indian Standard Code

IS: 875 (Part-3) for a basic wind speed of 50 m/sec (or) for prevailing andobserved wind speed at site.

1.8.7 EARTHQUAKE LOADS (EL)

The lateral forces will be established in accordance with the recommendations

of IS-1893. The site falls in Zone-III as per the classification of earthquake

zone.

The various site specific seismic parameters for the design

1) Peak ground horizontal acceleration (PGA)MCE : 0.09g

2) Peak ground horizontal acceleration (PGA)DBE : 0.05g

3)Reduction factor (R) is to be applied to the site specificdesign horizontal acceleration spectral coefficients toobtain the design acceleration spectra

a)For ordinary moment resisting steel frames withconcentric braces designed and detailed as per IS : 800

: 4.0

b)For ordinary moment resisting steel frames designed withconcentric braces and detailed as per IS : 800

: 4.0

c) For special moment resisting RC frames designed anddetailed as per IS: 456 and IS: 13920. : 5.0

d) for steel chimney : 2.0

e)For design of equipment resting on ground, reductionfactor should be taken as per IS code:1893 (Part 4) :2005

Note: g = Acceleration due to gravity1.8.8 CONSTRUCTION LOADS


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The integrity of the structures shall be maintained without use of temporary

framing, struts or ties and cable bracing, so far as possible. However,

construction or crane access considerations may dictate the use of temporary

structural systems. Special studies shall be made and documented to ensure

the stability and integrity of the structures during any periods involving use of

temporary bracing systems.

1.8.9 TAMPERATURE LOADS

For temperature loading, the total temperature variation shall be considered

as 2/3 of the average maximum annual variation in temperature. The average

maximum annual variation in temperature for this purpose shall be taken as

the difference between the mean of the daily minimum ambient temperatureduring the coldest month of the year and mean of daily maximum ambient

temperature during the hottest month of the year. The structure shall be

designed to withstand stresses due to 50% of the total temperature variation.

Suitable expansion joints shall be provided in the longitudinal direction

wherever necessary

The maximum distance of the expansion joints shall be as per the provisions

of IS: 800 and IS: 456 for steel and concrete structures respectively.

1.8.10 WAVE LOADS

The wind load shall be as per IS 4651Part I to Part V shall be referred.

LOAD COMBINATION

The structure has to be analyzed for various combination of loading as

prescribed in the latest relevant code.

1.9 ANALYSIS METHODOLOGY

Analysis of building / structure shall be carried out by 3D (Space frame

method) or by 2D depending on the type of structure and load details.

For analysis of structure, software like STAAD Pro of latest version shall be

used. For design of various structural elements like foundations, columns,

beams, slab etc. in-house developed software or STAAD Pro shall be used

wherever applicable / possible.


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1.10 DESIGN CRITERIA

The underground Intake water sumps are RCC water retaining structures and

shall be designed according to IS- 3370. In addition to design of structural

elements as uncracked section, limitation on crack width of 0.10 mm on bothfaces, considering severe exposer condition, shall be checked as per IS-456.

All components of the structure are to be designed for hydrostatic pressure,

earth pressure and also by following various loading condition as given below

i) Inside empty, but at outside, ground water is at FGL surcharge

load.

ii) Inside filled up with water up to full height of the basin and no

lateral pressure from outside of wall.

The dividing wall of the reservoir shall be designed considering one

compartment is empty and other being filled up with water.

iii) The base slab shall be checked against full hydrostatic uplift of

ground water without taking consideration of pressure release

valve. However in fore bay of the pump house they may be

provided subject to approval by the PURCHASER.

The RCC floor slab supporting pumps shall be checked for induced dynamic

load during sudden pump shut off condition. The pump floor shall also be

checked against resonance during normal operating condition.

STABILITY OF STRUCTURES

Design shall be checked against buoyancy due to the ground water during

construction and maintenance stages for structure like underground storage

tanks, pits, trenches, basements, etc. Minimum factor of safety of 1.5 against

buoyancy shall be ensured considering empty condition inside and ignoring

the superimposed loading. for purpose of calculating downward load due to

any overburden, the mass located vertically above and the inclined portion

depending on the angle of soil. The projected area of the base slab shall be

taken into consideration.

All building sub structure including pump houses shall be checked for sliding

and overturning stability during both construction and operating conditions for

various combinations of loads. Factor of safety for these cases shall be taken


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as mentioned in IS: 456 and other relevant IS codes. However following

minimum factor of safety shall be followed.

a) Factor of safety against overturning due to wind, seismic or other

lateral load shall be as per clause 20.1 of IS: 456.

b) Factor of safety against sliding shall be 1.5 minimum.

c) Factor of safety against uplift due to hydrostatic forces shall be 1.2 and

due to any other loads shall be 1.5.

Stability of the structure shall also be investigated for loading conditions

during construction, repair or other temporary measures. Lower factor of

safety may be used for such loading conditions as per relevant IS codes.

1.11 ARCHITECTURAL CONCEPTS

Intake Pump House shall be architecturally treated in such a way that it will be

aesthetically pleasing and satisfying all functional requirements. The

architectural treatment shall be compatible with the surroundings, taking full

consideration of climatic conditions and building orientation.

1.12 SITE VISIT AND SURVEY

The Bidder shall visit the site and assess the site conditions and to ascertain

the incidental work required to be carried out to commence the main work &

accordingly the cost is to be considered in his offer.

CONTRACTOR shall carry out the survey of the site before excavation and set

properly all lines and establish levels for various works such as earthwork in

excavation for grading, basement, foundations, plinth filling, roads, drains,

cable trenches, pipelines, etc. Such survey shall be carried out by taking

accurate cross sections of the area perpendicular to established reference /

grid lines at 5m intervals or as determined by ENGINEER based on ground

profile. These shall be checked by ENGINEER and thereafter properly

recorded.

1.13 SITE CLEARING

The area to be excavated / filled shall be cleared of fences, trees, plants, logs,

stumps, and bush vegetation, rubbish, slush, etc. and other objectionable

matter. If any root or stumps of trees are met during excavation, they shall also


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be removed. The material so removed shall be burnt or disposed off as

directed by ENGINEER. Where earth fill is intended, the area shall be stripped

of all loose/soft patches, top soil containing objectionable matter/materials

before fill commence.

The CONTRACTOR shall have to clean the site before the work is

commenced and after completion. The rates quoted shall be inclusive of all

charges likely to be incurred in carrying out the work of site clearance, initial &

final and shall also hold good under all conditions of weather.

Any minerals of any description whatsoever and all precious stones, treasures,

relics, antiques and other similar things that may be found discovered on the

site shall remain the property of Government and the CONTRACTOR shall

duly intimate the PURCHASER or any person duly authorized by him to

receive such property.

After completion of the work and before handing over the completed work to

the PURCHASER, the CONTRACTOR shall remove all unused and waste

material, remove temporary structures, ramps, platforms, etc., lying in the

vicinity of completed work and dispose off as directed by the PURCHASER.

Further, temporary structures for storing water etc., labour sheds or any other

sheds put up by the CONTRACTOR for facility of his work, shall be

demolished completely and waste materials disposed. The work site and other

areas, which were in his possession in connection with the execution of work,

should not present any unsightly or ugly appearance. The completed work will

not be taken over by the Engineer-in-charge, unless the final clearance of the

site is done as mentioned above.

1.14 EARTH EXCAVATION

Excavation shall be carried out as specified in the specification. Filling and

compaction shall also be carried out as specified.

Excavation for permanent work shall be taken out to such widths, lengths,

depths and profiles as are shown on the drawings or such other lines and

grades as may be specified by ENGINEER. Rough excavation shall be carried

out to a depth of 150 mm above the final level. The balance shall be

excavated with special care. Soft pockets shall be removed even below the

final level and extra excavation filled up as directed by ENGINEER. The final


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excavation, if so instructed by ENGINEER, should be carried out just prior to

laying the mud-mat.

CONTRACTOR may, for facility of work or similar other reasons excavate, and

also backfill later, if so approved by ENGINEER, at his own cost, outside the

lines shown on the drawings or directed by ENGINEER. Should any

excavation be taken below the specified elevations, CONTRACTOR shall fill it

up with concrete of the same class as in the foundation resting thereon, up to

the required elevation. No extra payment shall be claimed by CONTRACTOR

on this account.

All excavations shall be done to the minimum dimensions as required for

safety and working facility. Prior approval of ENGINEER shall be obtained by

CONTRACTOR in each individual case, for the method he proposes to adopt

for the excavation, including dimensions, side slopes, dewatering, disposal,

etc. The approval, however, shall not any way relieve CONTRACTOR of his

responsibility for any consequent loss or damage. The excavation must be

earned out in the most expeditious and efficient manner. Side slopes shall be

as steep as will stand safely for the actual soil conditions encountered. Every

precaution shall be taken to prevent slips. Should slips occur, the slipped

material shall be removed and the slope dressed to a modified stable slope.

Removal of the slipped earth will not be paid for.

In case any rock is obtained from excavation may be used for filling and

leveling to indicate grades without further breaking. In such an event, filling

shall be done in layers not exceeding 50 cm approximately. After rock filling to

the approximate level indicated above has been carried out, the voids in the

rocks shall be filled with finer materials such as earth, broken stone, etc. and

the area flooded so that finer materials fill up the voids. Care shall be taken to

ensure the finer fill material does not get washed out. Over the layer so filled, a

100 mm thick mixed layer of broken material and earth shall be laid and

consolidation carried out.

Excavation shall be carried out with such tools, tackles and equipment as

described.


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For all foundations below ground water table, excavation shall be done first

just up to ground water level and further excavation to founding level shall be

done just before concreting. As soon as founding strata is reached, lean

concrete mud mat shall be placed and concreting of foundation shall be

carried out with minimum loss of time. During entire operation, excavation

shall be kept dry by dewatering. CONTRACTOR shall programme his work to

ensure that the above procedure is strictly followed including providing

facilities for pumping of water to drain out the water and also to avoid any side

collapse.

APPLICABLE CODES

The following Indian Standard codes unless otherwise specified herein, shall

be applicable. In all case, the latest revision of the codes shall be referredto.

(a) IS:783 Code of practice for laying of concrete pipes

(b) IS:1200 Method of Measurement of Building works. (Parts 1 to 28)

(c) IS:2720 Method of test for soils

Part-2 Determination of Water Content

Part-7 Determination of Water content-Dry Density relation usingLight compaction

Part-8Determination of Water Content-Dry Density relation usingHeavy Compaction

Part-28Determination of Dry Density of Soils in-place, by the Sandreplacement Method

Part-29Determination of Dry Density of Soils in-place, by the CoreCutter Method.

(d) IS:3764 Safety code for excavation work

1.15 REFILLING AND COMPACTION

For filling the trench excavated material including the grabbed materials may

be used with the approval of Engineer / Consultant. The sand used for this

purpose shall free from boulders, rubbish, clay, silt etc., If good quality sand is

not available for the above purpose in full or part, required quantity of sea

sand shall be quarried and transported to the site of work. The payment for

such transportation shall be made under relevant item. The contractor shall

quarry the required quantity of sea sand from the nearby area.


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The sand required for filling shall be dumped and consolidated by approved

means. Payment shall be made only for the completed profile based on levels

taken before and after construction.

In case the sea sand is used for filling it should be thoroughly washed before

use.

Filling in trenches above pipes and drains shall be commenced as soon as the

joints of pipes and drains have been tested and passed. The back-filling

material shall be properly consolidated by watering and ramming, taking due

care that no damage is caused to the pipes.

Where the trenches are excavated in soil, the filling from the bottom of the

trench to the level of the centre line of the pipe shall be done by hand

compaction with approved earth in layers not exceeding 8 cm. Backfilling

above the level of the centre line of the pipes shall be done with approved

earth by hand compaction or other approved means in layers not exceeding

20 cm.

To ensure that the fill has been compacted as specified, field test shall be

carried out by the CONTRACTOR. The cost of the tests shall be borne by the

Contractor.

Field compaction test shall be carried out in difference stages of filling and

also after the fill to the entire height has been completed.

1.15.1 PLINTH FILLING

Plinth filling shall be carried out with approved material as described herein

before in layers, and compacted with mechanical compactor ENGINEER my

however permit manual compaction by hand tampers in case he is satisfied

that mechanical compaction is not possible. When filling reaches the finished

level, the surface shall be flooded with water, unless otherwise directed, for at

least 24 hours, allowed to dry and then the surface again compacted as

specified above to avoid settlements at a later stage. The finished level of the

filling shall be trimmed to the level / slope specified.

A compaction / road roller may be used only if permitted by ENGINEER. As

rolling proceeds, water sprinkling shall be done to assist consolidation. Water


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shall not be sprinkled in case of sandy fill.

The compacted surface shall be properly shaped, trimmed and consolidated to

an even and uniform gradient. All soft spots shall be excavated and filled and

consolidated.

At some locations/areas, it may not be possible to use rollers because of

space restrictions, etc., CONTRACTOR will then be permitted to use

pneumatic tampers, rammers, etc. and he shall ensure proper compaction.

1.16 MATERIAL FOR THE WORK

1.16.1 CEMENT

The cement shall be procured from the approved Vendors of

AGENCO/APPDCL. Cement shall be Sulphate resistant cement conforming to

latest relevant IS codes. Changing of brands or type of cement within the

same structure or portions thereof shall be permitted only with approval of

PURCHASER.

CONTRACTOR will have to make his own arrangements at his cost for the

storage of adequate quantity of cement. Cement bags shall be stored in a dry

enclosed shed (storage under tarpaulins will not be permitted), well away fromthe outer walls and insulated from the floor to avoid contact with moisture from

ground and so arranged as to provide ready access. Damaged or reclaimed

or partly set cement will not be permitted to be used and shall be removed

from the site. Storage arrangements shall be such that there is no dead

storage. Not more than 12 bags shall be stacked in any tier. The storage

arrangement shall be approved by PURCHASER. Consignments of cement

shall be stored as received and shall be consumed in the order of their

delivery. The Engineer-in-Charge will issue OK Cards to Cement stacks and

that cement which is 'Okayed only shall be used. The stacking arrangement

and issue system will be approved by PURCHASER.

Cement held in storage for a period of ninety (90) days or longer from the date

of manufacture shall be tested for normal consistency, fineness, setting time

and compressive strength. Should at any time PURCHASER have reasons to

consider that any cement is defective, then irrespective of its origin, date ofmanufacture and/or manufacture's test, such cement shall be tested again


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immediately as per Engineers instruction at reputed third party laboratory

and charges of the test to be borne by the contractor and until the results of

such tests are found satisfactory, it shall not be used in any work.

CONTRACTOR shall not be entitled to any claim of any nature on this

account.

TRANSPORTATION OF CEMENT

The Contractor shall make his own arrangement at his cost for transporting the

cement to his store and to the work spot and for handling, re-handling and

storing cement in good condition.

1.16.2 AGGREGATES

(a) "Aggregate" in general designates both fine and coarse inert materials

used in the manufacture of concrete.

(b) "Fine Aggregate" is aggregate most of which passes through 4.75 mm IS

sieve

(c) "Coarse Aggregate" is aggregate most of which is retained on 4.75 mm IS

sieve.

All fine and coarse aggregate proposed for use in the work shall be subjectedto the PURCHASER'S approval and after specified materials have been

accepted the source of supply of such materials shall not be changed without

prior approval of PURCHASER.

The materials shall be brought by the CONTRACTOR from the quarries

approved by the PURCHASER. For materials collected from quarries either

owned or controlled by the Government of Andhra Pradesh (or from private

bodies) or obtained from excavation for foundation and used in the work

covered by these specifications.

General approval of source of material or portion thereof shall not be

constructed that all materials taken form the source or portion thereof and the

CONTRACTOR will be held responsible for the specified quality of all such are

approved materials used in the work.

Aggregates shall except as noted above, consist of natural sands, crushed

stone and gravel from a source known to produce satisfactory aggregate for

concrete and shall be chemically inert, strong, hard, durable against


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weathering, of limited porosity and free from deleterious materials that may

cause corrosion of the reinforcement or may impair the strength and/or

durability of concrete. The grading of aggregates shall be such as to produce a

dense concrete of specified strength and consistency that will work readily into

position without segregation and shall be based on the 'mix'' designs and

preliminary tests on concrete specified later.

SAMPLING AND TESTING

All sampling and tests of fine aggregate shall be in accordance with the

recommended Indian Standard Specifications. All tests shall be made by

contractor under the supervision of PURCHASER at contractor's expense.

Routine control tests of fine aggregate at various stages in aggregate

processing plant will be made by the contractor. The CONTRACTOR shall

provide such facilities as PURCHASER may consider necessary for the ready

procurement of representative test samples and testing. Samples of the

aggregate for mix design and determination of suitability shall be taken under

the supervision of PURCHASER and tested by the CONTRACTOR in

presence of Purchaser well in advance of the scheduled placing of concrete at

no extra cost.

STORAGE OF AGGREGATES

All coarse and fine aggregates shall be stacked separately in stock piles in the

material yard near the work site properly to avoid inter mixing of different

aggregates. Contamination with foreign materials shall be avoided. The

aggregates must be of specific quality not only at the time of unloading at site

but more so at the time of lading into mixer. Rakers shall be used for lifting, the

coarse aggregates. Coarse aggregates shall be piles in layers not exceeding

1.2 meters height to prevent coning or segregation. Each layer shall cover the

entire area of the stock pile before succeeding layers are stacked. Aggregates

that have become segregated shall be rejected. Rejected material after

remixing may be accepted, if subsequent tests demonstrate conformance with

required gradation.

SPECIFIC GRAVITY

Coarse aggregates having a specific gravity below 2.5 t/m3 (saturated surface

dry basis) shall not be used without special permission of PURCHASER.


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1.16.3 FINE AGGREGATE

Fine aggregate except as noted above, and for other than light weight

concrete shall consist of clean natural river sand conforming to IS: 383. The

sand shall be clean, sharp, hard, strong and durable and shall be free from

dust, vegetable substances, adherent coating, clay, alkali, organic matter,

mica, salt, or other deleterious substances, which can be injurious to the

setting qualities, strength/durability of concrete.The grading of fine aggregate

for concrete shall be within the limits of either zone I or zone II of the IS 383,

table 4.

SCREENING AND WASHING

Sand shall be prepared for use by such screening or washing, or both, as

necessary, to remove all objectionable foreign matter while separating the

sand grains to the required size fractions.

GRADATION

Unless otherwise directed or approved, the grading of sand shall be within the

limits indicated here under:

PERCENTAGE PASSING FOR

IS Sieve Grading Grading Grading GradingDesignation Zone I Zone II Zone III Zone IV10 mm 100 100 100 1004.75 mm 90-100 90-100 90-100 95-1002.36 mm 60-95 75-100 85-100 95-100

1.18mm 30-70 55-90 75-100 90-100

600 micron 15-34 35-59 60-79 80-100300 micron 5-20 8-30 12-40 15-50150 micron 0-10 0-10 0-10 0-15

Where the grading falls outside the limits of any particular grading zone of

sieves, other than 600 microns I.S. Sieve, by total amount not exceeding 5

percent, it shall be regarded as falling within that grading zone. This tolerance

shall not be applied to percentage passing the 600 micron I.S. Sieve or to

percentage passing any other sieve size on the coarse limit of Grading Zone I

or the finer limit of Grading zone IV Fine aggregates conforming to Grading

Zone IV shall not be used unless mix designs and preliminary tests have


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shown its suitability for producing concrete of specified strength arid

workability.

FINENESS MODULUS

Sand shall conform to IS 383 Zone I or Zone II The fineness modulus is

determined by adding the cumulative percentages retained on the following IS

sieve sizes (4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron and 150

micron) and dividing the sum by 100.

SOUNDNESS

The average loss of weight of sand after 5 cycles of sodium sulphate

accelerated soundness test as specified in IS.2386 (part 5) shall not be more

than 10% and shall not be more than 15 % when magnesium sulphate solution

is used.

The Grading and fineness modulus of sand may be altered by PURCHASER

depending upon the requirements, suitability and availability. The contractor

shall procure process and supply the required sand at no extra cost.

1.16.4 COARSE AGGREGATE

Coarse aggregate for concrete, except as noted above and for other than light

weight concrete shall conform to IS: 383. This shall be of crushed stone and

shall be cleaned, and free form elongated flaky or laminated pieces, adhering

coatings, clay lumps, coal residue, clinkers, slag, alkali, mica, organic matter

or other deleterious matter.

It shall be roughly cubical in shape. The overall grading of the coarse

aggregate, viz., graded aggregate of nominal size 20mm shall conform to the

requirements specified in IS 383. The contractor shall, if required by the

engineer, obtain the specified grading by combining single aggregates in

proportions to give the specified grading.

SCREENING AND WASHING

Natural gravel and crushed rock shall be screened and/or washed for the

removal of dirt or dust coating, if so demanded by ENGINEER-IN-CHARGE.


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IS. Sieve Percentage passing for single sized aggregate of nominal size

Designation

63 mm 40 mm 20mm 16 mm 12.5 mm 10 mm

80mm 100 - - - - -

63 mm 85-100 100 - - - -40mm 0-30 85-100 100 - - -

20mm 0-5 0-20 85-100 100 - -

16 mm - - - 85-100 100-100 -

12.5 mm - - - - 85-100 100 ^

10 mm 0-5 0-5 0-20 0-30 0-45 85-100

4.75 mm - - 0-5 0-5 0-10 0-20

2.36mm - - - - - ' - 0-5

I.S. Sieve Percentage passing for graded aggregate of nominal size

Designation

40 mm 20mm 16 mm 12.5 mm

80mm 100 - - -

63 mm - - - -

40mm 95-100 100 - -

20mm 30-70- 95-100 100 100

16 mm - 90-100 -

12.5 mm ' - - - 90-100

10 mm 10-35 25-55 30-70 40-85

4.75 mm 0-5 0-10 0-10 0-10

2.36 mm - - - .

The Grading of coarse aggregate shall in general conform to the Grading as

given in IS.-383. The exact Grading of coarse aggregate for different items of

cement concrete works shall be approved by PURCHASER from time to time,

based on the laboratory tests. Such changes in the Grading shall be carried

out by CONTRACTOR at no extra cost.

The pieces shall be angular in shape and shall have granular or crystalline

surfaces. Friable, flaky and laminated pieces, mica and shale if present, shall

be only in such quantities that will not, in the opinion of the PURCHASER,

affect adversely the strength and/or durability of concrete. The maximum size

of coarse aggregate shall be the maximum size specified above but in no case

greater than 1/4th of the minimum thickness of the member, provided that the

concrete shall be placed without difficulty so as to surround all reinforcement

thoroughly and fill the corners of the form. For heavily reinforced concrete

members, the nominal maximum size of the aggregate shall be 5 mm less

than the clear distance between the main bar or 5mm less than the minimum

cover to the reinforcement whichever is smaller. The amount of fine particles


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occurring in the free state or as loose adherent shall not exceed 1% when

determined by laboratory sedimentation tests as per IS:238

The limits for flakiness and elongation tests will be specified by PURCHASER

based on tests from time to time and the CONTRACTOR shall procure the

aggregates as per requirements without claiming for any extra rate.

After 24 hours immersion in water, a previously dried sample shall not have

gained more than 1% of its oven-dried weight in air as determined by IS 2386

WORKS TESTS ON AGGREGATES

During the course of the Contract, fine and coarse aggregates shall be tested

at site as often as required by the Engineer and at the Contractors expense.Tests shall be carried out in accordance with the methods specified in as

below, unless otherwise ordered by the purchaser.

WORKS TEST ON AGGREGATES

Particle size IS 2386 Part I

Silt content by field settling test IS 2386 Part I

Moisture content IS 2386 Part III

Organic impurities content IS 2386 Part II

1.16.5 WATER

Water used for concreting production and curing shall be as per IS 456 -2000

requirement. Water used for both mixing and curing shall be clean and free

from injurious amounts of oils, acids, alkalis, salts, sugar, organic materials or

other substances that may be deleterious to concrete or steel. Potable water is

generally considered satisfactory for mixing and curing of concrete.

The sample of water taken for testing shall represent the water proposed to be

used for concreting, due account being paid to seasonal variation. The sample

shall not receive any treatment before testing other than that envisaged in the

regular supply of water proposed for use in concrete. The sample shall be

stored in a clean container previously rinsed out with similar water.

The initial setting time of test block made with the appropriate cement and the

water proposed to be used shall not be less than 30 minutes and shall not

differ by more than +/-30 minutes from the initial setting time of control test


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block, prepared with the same cement and distilled water. The test blocks shall

be prepared and tested in accordance with the requirements of IS: 4031.

1.16.6 REINFORCEMENT STEEL

REINFORCEMENT

All reinforcement bars for concrete structure shall be of CRS steel, grade Fe

500 with fusion epoxy coating of Minimum 175-300 microns conforming to

latest relevant IS codes. All reinforcement shall be corrosion resistant bar. The

bidder shall clearly indicate the coating system suggested on the

reinforcement or alternate system for corrosion resistance of reinforcement

and structure with proper technical specification.

STORAGE

The reinforcement bars shall not be kept in direct contact with the ground but

stacked on top of an arrangement of timber sleepers or the like.

If the reinforcing rods have to be stored for long duration, where storage for

more than three months is envisaged, they shall be coated with cement wash

before stacking and/or be kept under cover or stored as directed by

PURCHASER.

Fabricated rods shall be carefully stored to prevent the damage, distortion,

corrosion and deterioration.

LAPS

Laps and splices for reinforcement shall be shown on the drawings. Splices in

adjacent bars shall be staggered and the locations of all splices, except those

specified on the drawings, shall be approved by PURCHASER. The bars shall

not be lapped unless the length required exceeds the maximum available

lengths of bars at site.

BENDING

Reinforcing bars procured by the Contractor bent or in coils, shall be

straightened before they are cut to size. Straightening of bars shall be done in

cold and without damaging the bars. This is considered as the part of

reinforcement bending/fabrication work.


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All bars shall be accurately bent according to the sizes and shapes shown on

the detailed working drawings / bar bending schedules. They shall be bent

gradually by machine or other approved means. Reinforcing bars shall not be

straightened and rebent in a manner that will injure the material; bars

containing cracks or splits shall be rejected. They shall be bent cold, except

bars of over 25 mm in diameter which may be bent hot if specifically approved

by PURCHASER. Bars incorrectly bent shall be used only if the means used

for straightening and rebinding be such as shall not, in the opinion of

PURCHASER, injure the material. No reinforcement bars shall be bent when

in position in the work without approval, whether or not it is partially embedded

in hardened concrete. Bars having kinks or bends other than those requiredby design shall not be used.

FIXING

Reinforcement bars shall be accurately fixed by any approval means and

maintained in correct position shown in the drawings by the use of blocks,

spacers and chairs as per IS 2502 to prevent displacement during placing and

compaction of concrete. Bars intended to be in contact at crossing points shall

be securely bound together at all such points with 1.25 mm diameter soft

annealed steel wire. The vertical distances required between successive

layers of bars in beams or similar members shall be maintained by the

provision of mild steel spacer bars at such intervals that the main bars do not

perceptibly sag between adjacent spacer bars.

COVER

The cover for reinforcement bars shall be provided for the extremely exposure

condition as indicated in IS 456-2000.

INSPECTION

Erected and secured reinforcement bars shall be inspected and approved by

PURCHASER prior to placement of concrete.

1.17 SPECIFICATION FOR CONCRETE

1.17.1 MIX DESIGN

The concrete for all RCC works shall be as per specifications mentioned in

the Indian Standard and also to conform the design requirements.


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a) All the calculations relevant to the design of class of concrete mix.

b) The sieve analysis of aggregates which they proposed to use in the

works.

c) Full details of preliminary tests on concrete and

d) The weight of cement, sand and coarse aggregate to be adopted for

mixing.

Mix design shall be carried out as per IS: 10262 and IS: 456-2000. All the

preliminary tests and mix designs for all concrete works envisaged in the

contract shall be carried out by the contractor under the supervision of

Purchaser or a reputed third party concrete lab approved by the Purchaser.

The Contractor shall arrange all the materials, equipments, lab setup and

other resources required for mix design. Only those materials which are to be

used for Concrete production shall be used in mix design. PURCHASER shall

have powers to vary the proportions, water cement ratio and slump for the

specified work or works based on laboratory tests and the CONTRACTOR is

bound to adopt these changes on works without any extra cost.

The Contractor shall further note that the requirements of providing concrete of

specified quality in the field shall be his sole responsibility and he shall not be

eligible for any compensation in case the strengths obtained in the field do not

satisfy the criteria laid down, the work will be liable to rejection by

PURCHASER or a suitable reduction in the rate for concrete shall be effected

at the direction of the PURCHASER. The mix design shall be carried out with

approved state or Central Government Institute for the specified mix.

1.17.2 CONCRETE WORK

CONCRETE

The quality of concrete shall be of design mix specified in the drawing and

schedule of quantities.

The ingredients of the concrete such as fine and coarse aggregate shall be

measured by weight by means of an approved Batching Machine. Due

allowance shall be made to weight of water carried by the aggregate. The

actual amount added to the mixer being reduced as necessary. The decision


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of the Engineer / Consultant in this regard shall be final and binding on the

contractor.

The water cement ratio shall be the minimum possible having regard to proper

compaction by the respective means specified. The Concrete shall be mixed

in the Batch mixing machine of approved type and capacity. Where coarse

aggregate is over 20 mm, the concrete shall be mixed only in non-tilting type

of mixers. The resulting concrete shall be a uniform workable mixture of the

specified.

The batching, mixing, placing in position of concrete shall be as per the

guidelines stipulated in ISI 456-2000.

1.17.3 SAMPLING AND TESTING OF CONCRETE

Sampling of concrete shall be done as per the provision made in the relevant

IS or as directed by the PURCHASER or his representative. The additional

test if ordered shall also be carried out as per the direction.

All water retaining structures shall be tested for water tightness as per the

provisions of IS: 3370

If RCC floor / roof are assumed to act as diaphragm transmitting lateral loads

to braced bays it shall be provided with shear connectors. However,

whenever large / number of cut-outs are provided in the floor slab, horizontal

floor bracings shall be provided below slab to transfer horizontal force to

columns without considering diaphragm action from slab.

The minimum frequency of sampling of concrete of each class/grade shall be

in accordance with Clause 15.2 of IS 456-2000. Such samples shall be drawn

on each day for each type of concrete. Sampling, testing and acceptance

criteria shall be as per IS 456-2000.

CONSISTENCY

Slumps tests shall be carried out as often as demanded by PURCHASER and

invariably from the same batch of concrete from which the test cubes are

made. Slump tests shall be done immediately after sampling.

Test cubes shall be made and tested in accordance with IS 456 - 2000. If the

concrete test cubes do not give the stipulated strengths, PURCHASERreserves the right to ask CONTRACTOR to dismantle such portions of the


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work, which in his opinion are unacceptable and re-do the work to the

standard stipulated at CONTRACTOR'S cost.

The inspection and testing of concrete structures shall be done of IS: 456-

2000.

1.18 CURING

All concrete shall be cured by keeping it continuously damp for the period of

time required for complete hydration and hardening to take place. Preference

shall be given to the use of continuous sprays or ponded water, continuously

saturated coverings of sacking, canvas, hessian or other absorbent materials,

or approved effective curing compounds applied with spraying equipment

capable of producing a smooth, even-textured coat. Extra precautions shall be

exercised in curing concrete during cold and hot weather as outlined

hereinafter. The quality of curing water shall be the same as that used for

mixing concrete.

Certain types of finish or preparation for overlaying concrete must be done at

certain stages of the curing process and special treatment may be required for

specific concrete surface finish.

Curing of concrete made of high alumina cement and super-sulphated cement

shall be carried out as directed by ENGINEER-IN-CHARGE.

CURING WITH WATER

Fresh concrete shall be kept continuously wet for a minimum period of 10.

days from the date of placing of concrete, following a lapse of 12 to 14 hours

after laying concrete. The curing of horizontal surfaces exposed to the drying

winds shall however begin immediately after the concrete has hardened.

Water shall be applied to unformed concrete surfaces within 1 hour after

concrete has set. Water shall be applied to formed surface immediately upon

removal of forms. Quantity of water applied shall be controlled so as to prevent

erosion of freshly placed concrete.

CONTINUOUS SPRAYING

Curing shall be assured by use of an ample water supply under pressure in

pipes, with all necessary appliances of hose, sprinklers and spraying devices.


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Continues fine mist spraying or sprinkling shall be used, unless otherwise

specified or approved by PURCHASER.

ALTERNATE CURING METHODS

Whenever, in the judgment of PURCHASER, it may be necessary to omit the

continuous spray method, a covering of clean sand or other approved means

such as wet gunny bags which will prevent loss of moisture from the concrete

may be used. No type of covering will be approved which would stain or

damage the concrete during or after the curing period. Covering shall be kept

continuously wet during the curing period.

For curing of concrete in pavements, side-wall, floors, flat roof or other level

surfaces, the ponding method of curing is preferred. The method of containing

the ponded water shall be approved by PURCHASER. Special attention shall

be given to edges and comers of the slabs to ensure proper protection to

these areas. The ponded areas shall be kept continuously filled with water

during the curing period.

CURING COMPOUNDS

Surface coating type curing compounds shall be used only under special

permission of PURCHASER. Curing compounds shall be liquid type white

pigmented, conforming to U.S. Bureau of Reclamation specification. No curing

compound shall be used on surfaces where future blending with concrete,

water or acid proof membrane, or painting is specified.

CURING EQUIPMENT

All equipment and materials required for curing shall be on hand and ready for

use before concrete is placed.

1.19 SPECIFICATION FOR CONSTRUCTION AND KEY JOINTS

Concrete shall be placed without interruption until completion of the part of the

work between predetermined construction joints, as specified hereinafter.

Time lapse between the pouring of adjoining units shall be as specified on the

drawings or as directed by PURCHASER.

If Stopping of concreting becomes unavoidable anywhere, a properly formed

construction joint shall be made where the work is stopped. Joints shall be

either vertical or horizontal, unless otherwise shown on drawings. In case of


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an inclined or curved member, the joint shall be at right angles to the axis of

the member. Vertical joints in walls shall be kept to minimum. Vertical joints

shall be formed against a stop Board; horizontal joints shall be level and

wherever possible, arranged so that the joint lines coincide with the

architectural features of the finished work. Battens shall be nailed to the form

work to ensure a horizontal line and if directed, shall also be used to form a

grooved joint. For tank walls and similar work, joints shall be formed as per IS:

3370. Concrete that is in the process of setting shall not be disturbed or

shaken by traffic either on the concrete itself or upon the shuttering. Horizontal

and vertical construction joints and shear keys shall be located and shall

conform in detail to the requirements of the plans unless otherwise directed byPURCHASER. Where not described, the joint shall be in accordance with the

following:

COLUMN JOINT

In a column, the joint shall be formed 75 mm below the lowest soffit of the

beams including haunches if any. In flat slab construction, the joints shall be

75 mm below the soffit of column capital. At least 2 hours shall elapse after

depositing concrete in columns, piers or walls, before depositing in beams,

girders or slabs supported thereon.

BEAMS AND SLABS JOINTS

Concrete in a beam shall be placed throughout without a joint but if the

p

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