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N E P A L E L E C T R I C I T Y A U T H O R I T Y(AN UNDERTAKING OF GOVERNMENT OF NEPAL)

GENERATION OPERATION AND MAINTENANCEMEDIUM POWER PLANT OPERATION AND MAINTENANCE DEPARTMENT

ENERGY ACCESS AND EFFICIENCY IMPROVEMENT PROJECT

BIDDING DOCUMENT

forProcurement of

TRASH RACK CLEANING MACHINE AT INTAKEOF GANDAK HYDROPOWER STATION

Procurement of Plant(Design, Fabrication, Supply and Install)

Single-Stage, Two-EnvelopeBidding Procedure

Issued on: October 12th, 2012Invitation for Bids No.: GPS 068/69 -01 (R)ICB No.: GPS 068/69 -01 (R)

Employer: Nepal Electricity AuthorityCountry: Nepal

VOLUMEII OF III (EMPLOYER'S REQUIREMENT)

October 2012

This copy is for information only. Bidders shall base their bidson the hard copy to be purchased from NEA.

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Section 6 - Employers Requirements

This Section contains the Specification, the Drawings, and supplementary information thatdescribe the Works to be procured.

Table of Contents

1. Scope of Supply of Plants and Services: .......................................................... 1

2. General Technical Specifications ..................................................................... 2

3. Detailed Technical Specifications of Trash Rack Cleaning Machine, GantryCrane, Log Grappler, Electrical Works and Cable ............................................ 9

4. Detailed Technical Specifications of Silt Flushing Gate ...................................23

5. Detailed Technical Specifications of Trash Rack Panels .................................26

6. Detailed Technical Specifications of Civil Desilting Structure and removal of Silt33

7. Project Features ..............................................................................................47

8. Technical Data Sheets ....................................................................................49

9. Dismantling of Existing Gantry Crane and Trash Rack Panels ........................61

10. Inspection, Testing and Commissioning ..........................................................62

11. Drawings .........................................................................................................69

12. Supplementary Information .............................................................................69

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1. Scope of Supply of Plants and Services:

1.1 Design, Manufacturing, Supply, Installation, Testing and Commissioning of onemovable rope driven Trash Rack Cleaning Machine consisting of the gantry, hoistingunit with ropes, cleaning rake, electric and hydraulic control unit, travel gears, container

including mandatory spare parts suitable for Gandak Hydropower Station IntakeStructure.

1.2 Design, Manufacturing, Supply, Installation, Testing and Commissioning of one gantrycrane rope drum hoist type including structural attachments to the gantry for carryingand lifting stoplog (existing) and mandatory spare parts suitable for GandakHydropower Station Intake Structure.

1.3 Design, Manufacturing, Supply, Installation, Testing and Commissioning of one loggrappler with rotator having hydraulic operation including mandatory spare partssuitable for Gandak Hydropower Station Intake Structure.

1.4 Design, Manufacturing, Supply, Installation, Testing and Commissioning of one set ofvertical slide type silt flushing gate operated by hydraulic cylinder suitable for GandakHydropower Station Intake Structure.

1.5 Design, Manufacturing, Supply, Installation, Testing and Commissioning of completeset of Trash Rack panels (excluding 1

stand 2

ndstage embedment) for each intake

screen section suitable for Gandak Hydropower Station Intake Structure.

1.6 Design, Excavation, Foundation, Cement Concreting, Steel Reinforcement, Centeringand Form Work and construction of flushing arrangement (abutments, duct walls,approach canal, wing wall etc) for provision of Civil Desilting Structure in front of Intakefor diversion of silt through silt flushing gate.

1.7 On-site supervision of the complete assembly of rail tracks, TRCM Unit, start-up,commissioning and operation and maintenance training of staffs by the manufacturer

including daily allowances, food and lodging, travel and transportation costs.

1.8 All services pertaining to one time removal of accumulation of silt in front of intake.

1.9 All works in relation to temporary diversion of canal and dewatering works required tocarry out the aforesaid works.

1.10 Dismantling of existing Gantry and Gantry Crane.

1.11 Supply and connection of mains power supply up to the junction box on the intakedeck.

1.12 Supply and erection of additional rail tracks consisting of rail track beams, clamps, high

tensile screws, fixation materials, spacers and bumpers.

1.13 Civil Works for adaptation, modifications, and other necessary works related to theinstallation of the rail tracks of the proposed TRCM.

1.14 Recommended spare parts for trouble free operation for at least 5 years

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2. General Technical Specifications

2.1 General Scope of Work

The scope of work shall consist of the work as described in Serial Number 1above suitable for the configuration of Gandak Hydropower Station Intake. The

work (Referred as TRCM Unit) shall mainly consist of the following components:

a. Trash Rack Cleaning Machine (TRCM)b. Gantry Cranec. Log Grappler (Hydraulic Jib Crane attached to TRCM) with gripper and rotatord. Rail Trackse. Silt Flushing Gate with Hydraulic Hoistf. Removal of existing Trashrack panels and installation of new Trash Rack Panels (

excluding 1st

and 2nd

stage embedment)g. Dismantling of existing gantry crane and Trash Rack Panelsh. Electrical Power Supplyi. Adaptations, modifications and other necessary civil worksj. Temporary diversion of canal and dewatering works

k. Desilting civil structure and silt flushing gate systeml. Installation, testing, commissioning and operation and maintenance training

The trash cleaning machine will move on rail tracks. The rail, rail fixing fixture andembedment shall be in the scope of works. The block out details for fixing rails andfixtures and power supply details to suit the machine operation, will be given by theTRCM Bidder (if not provided herewith) and a point for power supply at one end near tostructure will be given by the owner. The flexible cables or any other suitable means fortapping the power to operate the TRCM, the suitable earthing to all machineequipments as required and adequate lighting provisions to illuminate theworking/surrounding areas on machine shall also be considered to be covered by thescope work.

2.2 General Requirements

2.2.1 The design of the TRCM Unit shall consider using the existing guides, rails andother embedment to the extent possible.

2.2.2 The Bidder shall offer travelling type auto/semi-auto/manual operated, ropedriven TRCM having hydraulically operated apron to ensure removal of debrisand trashes from fixed trash rack of the intakes to the depth of around 19 m. Itshall includes rack lifting and dumping mechanism, skip grab with wheels &teeth, trash disposal trolley etc. and all other necessary accessories for properoperation of the raking machine to cater to the specified design considerationsand operating requirements. The offered equipment shall also be capable oflifting floating debris/twigs from the water surface, as well as remove the trasheswedged in between the screen bars under water.

2.2.3 The Bidder shall submit the general layout arrangement diagrams of offeredTRCM Unit in their Technical Proposal (VOLUME-I) describing in detail theadvantages and its limitations.

2.2.4 Necessary tools, plants and machineries required for the installation of newTRCM unit and dismantling of existing gantry crane and its transportation,loading and unloading at the site specified by NEA shall be in the scope of theBidder.

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2.2.5 Necessary chipping, grouting, temporary diversion of canal, dewatering and othercivil works related to the installation of TRCM unit shall be in the scope of theBidder.

2.2.6 The requirement of works also includes new trash rack panels to replace theexisting trash rack panels. The design, supply of trash rack panels, fabrication,delivery, storing, aligning, erecting, supporting, inspecting, painting, testing andguarantee of this equipment in accordance with the detailed technicalspecification as specified herein and approved by the Engineer.

2.2.7 Painting Works

2.2.7.1 All sheet steel works shall be phosphated in accordance with thefollowing procedure and in according with applicable standards.

2.2.7.2 Oil, Grease, Dirt shall be thoroughly cleaned by emulsion cleaner.

2.2.7.3 Pickling with dilute acid followed by washing with running water, rinsewith slightly alkaline hot water and drying shall remove rust and Scales.

2.2.7.4 After Phosphating, thorough rinsing shall be carried out with clean water,followed by final rinsing with dilute dichromate solution and even drying.

2.2.7.5 The Phosphate coating shall be sealed by the application of Two Coats ofstaving type Zinc Chromate primer. The first coat may be "flash dried"while the second coat shall be staved.

2.2.7.6 After application of the Primer, Two coats of finishing synthetic EnamelPaint shall be applied, each coat followed by staving. Touch up shall beapplied after completion of Tests. The color for the finishing paint shallbe light Grey or as approved by the Owner.

2.2.7.7 The Final finished thickness of paint film on steel shall not be less than

100 microns.

2.2.7.8 Finished painted surface shall present aesthetically pleasing appearancefrom runs and drips.

2.2.7.9 A small quantity of finishing paint shall be supplied for minor touching uprequired at site after the installation.

2.2.8 It is also proposed to install one set of 2000 mm x 1000 mm gates for silt flushingcanal. These gates shall be regulating type and shall be operated with the help ofindividual hydraulic hoist mounted directly above the bonnet cover. The gate leafshall move in a frame which shall consist of a body that shall in turn house thegate in open position. The body and the bonnet shall be embedded in the

concrete. The bonnet shall be covered by a bonnet cover with a stuffing boxthrough which the stem rod of hydraulic hoist will pass. The silt flushing gate shallbe designed for extreme condition of silt load as referred in IS: 6512. The depthof the sill shall be considered as the total depth of the silt flushing canal.

2.2.9 The design shall focus on features like flexibility, robustness and multifunctionaldesign to complete additional tasks such as sediment removal and the lifting andlowering of stop logs and screens.

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2.3 Codes & Standards

The TRCM Unit shall be designed in accordance with internationally recognizedEuropean standards (DIN (German Industry Code), EN (European Codes), FEM(European Codes) and/or IS (Indian Codes)) for the design and requirements ofcranes, which results in an increased lifecycle of the equipment, highest availability

and low operating costs.

Mechanical Design

DIN 15018/15019DIN 1519/DIN 1520

Two basic codes for the design of a Trash Rack Cleaning Machine ora Crane Standard for rack lifting gear & rack lifting

DIN EN 18800Additional code used for the design of the heavy steel structures,welding joints, etc.

DIN 15070/15071 Used for the design of the wheels and bearings.

DIN 15020 Used for the design of rope drums, ropes and hoist motors.

IS 5620 Recommendation for structural design of slide gate

IS 11388 Recommendation of design of trash racks for Intake

DIN 1055Comparable with the International Building Code. In this code windloads, snow loads, etc. are specified as to which have to be used forthe design calculation of the Trash Rack Cleaning Machine.

FEM 1001

Code written by the European Community, this code includes rules forthe design of hoisting appliances such as cranes or Trash RackCleaning Machines. This will be used in addition to DIN 15018 and15019.

EN 10029 Specification for steel materials

DIN 1543 Specification for stainless steel

DIN 15026 Marking of danger areas

Painting

DIN EN ISO 12944Specification for painting machines, such as Trash Rack CleaningMachines or Cranes. Also included in this code is the specification forsand blasting.

DIN EN ISO 4628 Definition of "degree of rusting"

DIN EN ISO 1461 Hot dip galvanizing

Mechanical Machining

DIN ISO 2768-mk General tolerances (measure of length and angle)

ISO 9013-IAG Tolerances for cutting of steel plates

DIN 6930-m Steel stampings

DIN ISO 13715 Work piece edges

ISO Certifications

DIN EN ISO 9000 Definition of Quality Management/Quality Control

DIN EN ISO 9001 Requirement for ISO certification

Start Up

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DIN 15030 Start-Up of Trash Rack Cleaning Machine or Cranes

Welding

DIN 18800 parts 1and 7

The basic regulations for all other welding regulationsCompany Qualification classification E

ISO 5817 Classification for irregularityISO 15614 Inspections of the welding joints

EN 287 Requirements for welders

EN 10204 Charge number persecution

Electrical Design

EN60204 Safety of Machinery, Electrical Equipment of Machinery

EN60439 Low Voltage Switchgear and Control Gear Assembly

VDE0100Erection of Power Installations up to 1000 V, Verification, InitialVerification

Corrosion Protection

Triple anti-corrosion treatment is applied to the following main components:

All structural steel parts (gantry) incl. apron.

Shotblasting: Sa 2 acc. to ISO 12944

Primer: (AGROZNIK SW-60 m

Intermediate coating: (AGROPOX HS 250 EG-80 m)

Top coating: (AGROPUR COLOR-60 m)

Total dry film thickness is: 200 m

Purchased parts are protected according to the manufacturers standards. Thecleaning Rack is hot dip galvanized.

2.4 Conditions of Service

2.4.1 All Plants and Equipments supplied under this Contract shall be suitable for thefollowing Site and System Conditions.

2.4.2 System Electrical parameters

Rated Service Voltage : 230 V/ 380 VNumber of Phases : 1/3Frequency : 50 Hz

2.4.3 Climatic Conditions

All Plants and Equipment supplied under the Contract shall be entirely suitablefor the Climatic Conditions prevailing at Site.

The Seismic Factor is 0.15g.Atmospheric pollution is Low and Special Insulator Design or Washing is notrequired.

Maximum ambient Shade Temperature : 50C

Minimum Ambient Shade Temperature : 0C

Annual Average Temperature : 35C

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Maximum Wind Velocity for design purpose: 34.4 m/sec (to be confirmed)Rainfall : 1500 mm/annum (to be confirmed)Relative Humidity

Maximum : 100% (to be confirmed)Minimum : 20% (to be confirmed)

Altitude : 150 MASL (Approx) for GandakAtmospheric Pollution : Light

The Information provided in this Clause is given solely for the General Assistanceof the Bidder and neither responsibility for it will be accepted nor will any claimbased on this clause be considered.

The Bidder is strongly advised to survey the sites covered under this Contract toacquaint with the Site Conditions.

2.4.4 The Contractor shall be responsible for surveying, boring, geological and subsoilconditional for all foundation, and for the precise location of theequipments/facilities in the Project.

2.4.5 The Contractor shall locate and record on the construction drawings, all

interfacing utility facilities/structures or other obstruction. Damage to existingequipment and the Contractor at his own expense shall repair structures.

2.5 Drawings, Instruction and Maintenance Manuals

The Contractor shall submit Detailed Drawings, Instruction and Maintenance manualsand parts list with recommended stock quantities for the equipment furnished, prepareand submit detailed engineering, Design and Construction drawings pertaining to allmechanical and Electrical Equipment and Installations in the power station. TheDrawings/Manual submitted by the Contractor should also be in the form of digitizedform (Compact Disk). The Drawings to be furnished by the Contractor shall include,but not be limited to the following:

a. Single Line and Three Lines Diagram.

b. Schematic of mechanical and electrical diagram of TRCM Unit including erectionin existing trashrack and intake structure.

c. Layout of equipments at intake.

d. Detailed Cable Schedule list and cable summary, specifying cable identificationnumber, routing and length of the cable.

e. Details of hydraulic and electric control panel. Panel front and rear elevationdrawings showing dimension and identification of each device and completenameplate schedule.

f. Control, Protection and monitoring Schemes. Calculation and co-ordination forselecting Operation of Monitoring/Protective Relays.

g. Instruction Book, spare Parts' lists, Materials lists and any other documentspertaining to the Substation and required for Construction, Operation,Maintenance and Repair.

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h. Suitable detail design, drawing (construction and as built) and quantity estimateas per site condition with surveying works all complete for civil erection, repairand maintenance of desilting civil structure and silt flushing gate system.

The successful Bidder will be required, at the time of signing of the Contract; to supplyadditional copies of the above drawings as may be selected by the Employer. Thesedrawings, together with such drawings originally issued with the Tender documentswill then form part of the Contract Document and be signed both by the Employer andthe Contractor for identification purposes.

i. Prior to commencement of the work, the Contractor shall submit detailed designdrawings and data to the Employer for approval. Should the Employer direct thatmodifications be made in order to satisfy the requirements of the Specifications,the Contractor shall submit revised drawings for approval. Alteration in theContract price shall not be allowed by reason of the drawings modifications.

ii. The Contractor shall prepare and furnish to the Employer such drawings,calculations, and data on materials and equipment (hereinafter in this provision calleddata) as are required for the proper control and completion of the work, including butnot limited to those drawings, data and calculations specifically required elsewhere in

the Technical Specifications.

iii. The Metric System shall be used and notations shall be in English. Drawings,calculations, and data shall be furnished as specified. All drawings and data will besubject to review by the Employer for conformity with the Technical Specification andContract Drawings and upon meeting review requirements shall become the propertyof the Employer.

2.6 Recommended Spare Parts and Tools to be Provided

The bidder should specify the recommended spares parts and tools as required for atrouble free operation for at least 10 years.

2.7 Installation Testing and Commissioning

The bidder should furnish qualified supervision and construction personnel for theInstallation, Testing, Commissioning and Final system testing and checking out of theequipment listed above and details in the Price Schedule. The testing andcommissioning of the equipment should be in the supervision of the manufacturer'srepresentative and should guarantee the test performed. The work shall be performedin close cooperation and collaboration with the Employer / Engineer.

2.8 Design Requirements

While designing the TRCM Unit Bidder shall consider the following points.

a) The proposed TRCM Unit shall remove and ensure that the racks are clean of anyfloating and submerged debris and should be capable to dislodge the solid debris

caught in between the trash bars. Its operation should not get affected by such

solids debris between trash bars. It should also be able to extract jam-packed

debris under heavy water pressure.

b) The cleaning shall be guaranteed during full flow through the intake and even with

a cross water velocity of trash rack.

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c) Machine shall be capable to indicate position for cleaning in front of each

compartment.

d) The rake head should be designed to indicate such that the water head loss is

minimum.

e) The trash cleaning Rack shall be designed to clean the width and depth of all trash

racks. The trash so collected after each cleaning cycle shall be discharged into a

suitable manually operated trash disposal container provided along with the TRCM.

The trash disposal container shall be attached to the TRCM and can be detached

at the end of the cleaning cycle so that it can dump the trash automatically at a

suitable location. The trash disposal vehicle shall fit and operate within the

dimensions of the TRCM, with adequate clearance around all structures,

equipments and devices.

f) The operation of raking function as well as lifting of the stoplog may be done from

one operator cabin or from different operator cabins.

g) All components, devices and assemblies shall be weatherproof, for outdoor use

and designed for the site climatic conditions. Exposed equipments shall be

provided with covers wherever required. All members, devices etc. which could

otherwise trap water shall be provided with drain holes. All structural tubing and

piping shall be seal welded to prevent entrapment of moisture. All motions shall be

controlled by hydraulic motors. The electric supply to the equipment will be fed by

cable mounted on cable reeling drum.

h) The design of TRCM Unit shall give due consideration to the existing civil and

mechanical structures and space constraints.

i) The offered TRCM unit shall have the facilities for Automatic/Semi-

automatic/Manual modes of operation as mentioned in specifications. The design

shall include all allied facilities required for making TRCM operable automatically.

However, the experiences have shown that the automatic operations are not as per

the expectations. This indicates that the machine shall be predominantly subjected

to manual mode of operation. The design shall consider this aspect of operation.

j) The offered equipment and goods shall be in conformity with the specifications.

The Bidder shall fill in Technical Data Sheet provided in the Bidding document. In

order to prove that the Goods offered are of acceptable quality and standard and in

conformity with the specifications, the Bidder shall furnish documentary evidence in

the form of literature (catalogue), drawings, detailed description of goods withessential technical and performance characteristics and type test reports wherever

called for. The type test certificate, if applicable, shall cover all the type tests as per

the latest version of relevant standard mentioned in the specification. The type test

conducted earlier than five (5) years from the last date of submission of Bids shall

not be acceptable.

k) It is not the intent to specify completely herein all details of Design and

Construction of Equipment supplied. However, the equipment supplied shall

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conform, in all respects, to high standards of Engineering, Design and

Workmanship and be capable of performing in continuous commercial operation up

to Contractor's guarantee in a manner acceptable to the Employer who will

interpret the meaning of Drawings and Specifications and shall have the power to

reject any work or material which in his judgment are not in full accordance

therewith.

3. Detailed Technical Specifications of Trash Rack Cleaning Machine,Gantry Crane, Log Grappler, Electrical Works and Cable

3.1 Working Principle

(a) The primary purpose of the trash rack cleaning machine is to keep the water flowunrestricted and free of losses to the turbine by removal of all kinds of debrissuspended (floated) or submerged in the water such as municipal garbage, grass,weeds, leaves, plastic, branches, small trees, carcasses entering a trash rackintake area. The trash cleaning machine shall be used to efficiently cleaning thetrashrack installed at the intake structure. The cleaning machine and the swiveling

rake shall be designed in a fashion to ensure the penetration of the rake eventhrough layers of debris. The trash cleaning machine shall consist of trash rakewith its tilting front panel mounted on steel structure, long travel motion assemblies,and rake winch, control/operation equipment mounted in operator's cabin with allnecessary equipment, accessories and mountings for satisfactory and safeoperation of the machine. The frame of the cleaning machine shall be fitted with atleast four wheels. A suitable trash disposal arrangement shall be provided. Trashcollected during the combing operation will be unloaded through tilting apron intotrolley (manually operated) provided with the TRCM. Trash collected in trolley willbe taken away from the machines parking position with prime mover/truck forunloading the trash into trash disposal area.

The TRCM shall be able to handle all type of trashes subjected to continuous duty

cycle.

(b) Brief Description of the Operational Problems of the Present System

The small trashes after gaining enough weight due to prolong soaking in watersinks and make their way into the intake area beneath. These trashes choke theintake screens thereby reducing the flow of water into the turbines resulting in lossof generation. While attempts are being made to clean the intake area manually bydeploying cleaning personnel in shifts, however, the following reasons have provethe way to be ineffective.

1. The volume of trashes to be removed is enormous especially during monsoonwhen the river is inundated. Manual operation is daunting, cumbersome as wellas risky.

2. The floating trashes accumulated at the intake get wedged into the trashscreens due to suction force of the generator during operation. This forces theunit to be shut down for removal of trashes.

3. The logs from tree branches, carcasses and human body are difficult toremove without the help of log grappler.

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4. The lower embedment of trash racks are submerged in the mass of silt due tolarge deposition and unavailability of silt flushing system thereby reducing theeffective volume of water in the forebay.

5. The absence of silt disposal system has had adverse effects on the turbineparts and wicket gate assembly along with the hydraulic and cooling system.

6. The existing gantry crane has remained old, unused and ineffective and lacksbasic safety features. This needs to be replaced.

3.2 Operational Requirements

(a) General

The trash rack cleaning machine will be designed for fully automatic, semi-automatic operation and manual operation. Screen pollution is monitored through alevel difference control. If this monitoring reacts, an automatic cleaning cycle isperformed. In semi-automatic operation mode, the machine works with theautomatic program, start and stop are defined by the operator for a single screen

intake (selectable). The operator can perform all trashrack cleaner functions inmanual mode with a wired hand held remote control unit which is connected to themain switch cabinet.

As soon as the start instruction is given to machine in fully automatic mode, themachine shall be able to positioned itself exactly on a particular desired bay andclean the bay on which it is located, thereof dispose the trash to trolley and thencome back to its rest position after completing the cycle. In the Manual mode allof the functions including indexing (travelling to the next position), raking anddumping functions shall have separate pushbuttons. In the Automatic andSemiautomatic mode only one pushbutton shall move the rake through onecomplete cycle of lowering, raising, dumping, and indexing.

The cabin shall be located and provided with sufficient window area so as to alloweasy visual monitoring of all raking operations and the entire intake deck. Thecabin shall be provided with an interior light, electric heater, ventilating fan, paddedoperator seat, and lockable door. All electrical equipment and controls shall belocated above the deck level. All wiring shall be in accordance with Standards andall conduits shall be rigid steel conduit. A position indication system shall beprovided in the cabin to indicate the rake head depth in meters and centimeters

below deck level.

(b) Rake Head

The rake head shall be suspended by a hydraulic actuator spaced to suit the trashrack bar spacing of 80 mm. Rake head should be provided with a base trolley sothat the cleaning of the rake is to be done during lowering of the rake. The shape ofthe cleaning rake shall be in compliance with a tested design for variable speedand minimum water head loss. The rake should be fabricated out of sheet metalwith proper reinforcing ribs etc. The toothed blade shall be made of suitablematerial. It should be able to adjust and replace with other type of bladeaccessories. The rollers should be provided with maintenance free bearings andaxles shall be made of stainless steel.

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The cleaning rake and the toothed strip in particular shall be adaptable to thematerial carried by the water. The shape of the cleaning rake shall permit cleaningeven if there are thick coats of the deposited material of about 0.5 m to 1 m nearthe rack at the bed level. Suitable provision shall be made in rake head to preventopening of the rake during hoisting of the rake with trash. The rake shall beprovided with load safety devices, which will automatically stop the raking operationif the hosting boom either becomes stuck or overloaded beyond the maximum loadcarrying capacity of the rake. An alarm shall sound if these events occur. Provisionfor smooth acceleration and deceleration of rake head during starting and stoppingshall be kept. Also stopping of the rake head at the highest as well as the lowestposition shall be ensured by limit switches. In the highest position the rake shallopen to unload debris in hopper or trolley.

(c) Cleaning of Trash Racks:

The cleaning machine carriage shall traverse horizontally driven by electric motorin order to clean three intake bays screens in selective basis or in sequence. Therack cleaning machine shall have a rest position. As soon as it receives acommand to start operation, it shall clean a rack span, shall empty into the debristrolley and shall come to the rest position. Pressing of the "forward" or "backward"push button shall cause the trash cleaning machine to travel to the next cleaningspan. The operation may be repeated by pressing the proper push buttons onevery rack span.

(d) Long Travelling (LT):

Momentarily pressing the "FORWARD" push button shall cause the cleaningmachine to move forward until the traversing motion is stopped by momentarilypressing the "HALT" push button or by operation of the limit switch for the centreline of next cleaning span or the extreme forward position. Similarly, momentarilypressing the "BACKWARD" push button shall cause the cleaning machine to movebackward until the traversing motion is stopped by momentarily pressing the"HALT" push button or by operation of the limit switch for the centre line of nextcleaning span or extreme backward position.

(e) Interlocking:

Traversing the gantry shall be possible only when the trash rack and hook andauxiliary hoist are in extreme raised position and the rake winch mechanism is idle.Suitable interlocking arrangements shall be provided so that:-

i) Suitable interlocks for preventing more than one drive operation simultaneously.

ii) When the trash cleaning machine is in traversing motion, hoist mechanism shallremain stationary, and even pressing of "RAISE" or ' LOWER" push buttons,shall not cause the operation of trash rake and auxiliary hoists.

iii) When the trash rack or auxiliary hoists mechanism is in operation, the traversingmotion of cleaning machine shall not be possible even by pressing the"FORWARD" or "BACKWARD" push buttons.

(f) Location of Control panels:

The operation of the trash rack, auxiliary hoist and the traversing mechanism etc.shall be from the operator's cabin mounted on the frame. The operator's cabin shall

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be mounted on the top of cleaning machine and provided with sufficient windowarea and so located that operator gets a clear view of the trashracks, operation ofthe trash cleaning machine and auxiliary hoists.

(g) Hoisting Mechanism of TRCM

The hoisting unit for the rake shall consist of a rope driven solution with a capacityto lower the rake (attached to its extreme end) to the level up to EL 513.80 m(bottom level of the trash screen) in open position and subsequently raise the rakeup to the unloading apron in closed positions. The rake shall be suitable to slide/rollas per the slopes given in Specification. The hoist shall be of sufficient capacity notless than 1 ton so that the rake can be raised with maximum trash accumulated onit. The hoist motion shall stop automatically at the two extreme positions of the rake(i.e. at the bottom of the trash rack & at the unloading position) or in case requiredanywhere in between the top and bottom as desired by the operator.

(h) Opening/Closing Mechanism of the Rake Grip

This motion shall be achieved by means of a suitable capacity hydraulic cylinder to

operate the opening/closing of the rake grip. The rake shall be in open positionwhen it is being lowered and shall be closed when it is being hosted. The rake shallalso be able to stop at any intermediate position to fully close/open position asdesired by the operator.

(i) Hoist Control Module

The hoist control module shall include a hydraulic power unit and an electric motor.These parts shall form a single integrated equipment package mounted on acommon frame and installed in a single housing. The hoist control module shallalso include all interconnecting wiring between these two sub-assemblies, requiredhousing and all other appurtenances.

The host control module shall be provided with separate sets of hydraulic controland power components for each rake motion arranged on a common hydraulic fluidreservoir and separate sets of hydraulic control components for each rake motion.The hydraulic and electrical and power components shall be suitablyinterconnected to enable interlocking so that wherever required one motion inoperation then other motion of the rake are not possible.

The control module will be housed on the gantry structures. Sufficient space shallbe provided all around the control module to facilitate operation and maintenance.The location of the control module shall not interface with the free movement of themen and material on the gantry structure.

(j) Fluid Reservoir

The hydraulic fluid reservoir shall be of single unit. The reservoir shall be equippedwith a sight fluid level gauge, minimum oil level indicating device, dial typethermometer to indicate fluid temperature, drain valve connection, a magnetic plugtype drain, arranged to permit complete drainage, a filler pipe provided withstrainer, and pipe connections to a fluid purification device.

(k) Hydraulic Control Panel for TRCM

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The hydraulic control panel shall be mounted on the gantry frame structure of themachine. All hydraulic components which need to be accessible for manualoperation and all gauges shall be mounted on the hydraulic control panel. Strainersand filters shall also be easily accessible for maintenance; their location shall besuch that the draining oil during exchange of the filter elements shall not spoil theinstrumentation including pressure gauges and pressure switches and other criticalitems. All components shall be arranged in an orderly and functional manner, andthey shall be removable without removing the surrounding components and piping.

3.3 Structural Arrangement

(a) Frame:

Care shall be taken in the design to produce aesthetic look of the cleaningmachine. The trash cleaning machine shall be constructed of steel sections andplates and shall be either of bolted or welded construction. The legs shall be of thebox type, with all angles on the inside of the leg. Field welding will not beacceptable. Diaphragms shall be provided to distribute the loads properly to thetwo sides of the legs and stiffeners shall be provided where necessary. Bearing

surfaces of joints, designed to transmit stress by bearing shall be machine finishedto provide full contact. Shop connections in the frame shall be bolted or welded sothat the surface of the trash cleaning machine including the outside of the frame,viewed along the runway, will be a plane surface except for the projection of boltheads.

(b) End carriages with End Buffers and Mounting for LT Drives:

End carriage shall be of box girder construction and shall have a wheel base to suitthe operating requirements. Sufficient number of wheels (not less than 4 numbers)shall be provided. These shall be fully equalized and shall serve as cleaningmachine travel base. End carriages shall have suitable frame works forhousing/fixing LT drives, spring/hydraulic buffers, columns/legs of cleaning

machine etc. Sufficient number of diaphragms shall be provided to distributeproperly the loads from columns. The connections to columns should be by longradius gusset plates. It shall be provided with suitable means for anchoring thecleaning machine when it is left unattended. This may be done by means of railclips or screw jack or chain anchor on each rail end carriage.

(c) Leg/Columns of Cleaning Machine:

The legs of cleaning machine shall be connected to the cross members by heavygusset plates in a manner that will prevent skewing and ensure rigidity andstrength. Diaphragms shall be provided to distribute properly the loads from thecross members to the sides of the legs. If the centre lines of the legs are notdirectly over the centre lines of the runway rail, the eccentricity shall be considered

in determining the stresses.

Suitable staircase (cage type) shall be provided for approach to machinery housingas well as to operator's cabin.

(d) Operator's Cabin:

Operator's cabin shall be situated in such a way that the operator is able to seeoperations. It shall be on the top of the cleaning machine. Its dimensions shall besuitable for housing control equipment and the operator comfortably. The cabin

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head room in cabin shall be minimum 2 meters. The cabin shall be so designedthat it shall afford the operator an unrestricted view of the lifted load and as clearview as possible of the surroundings. It shall be of closed weather proof type withheater and fan with opening windows (slewable type) for proper ventilation. It shallbe rigidly built with structural steel, suitably braced to prevent movement betweencabin and supporting members. A thick rubber (neoprene) insulated mat shall beprovided in the cabin floor over chequered plate flooring. The operating panels andinternal fittings shall be properly and systematically located for convenience of theoperator. Necessary instruction plates shall be provided in the cabin.The operator cabin for raking as well as for lifting of intake stoplog can be from oneoperator cabin or from different operator cabin as per the latest practices andinnovations.

The operator's cabin/cabins shall be located and provided with sufficient area in theunit so as to allow easy visual monitoring of all raking operations of the entireintake deck and also to clearly see the lifting/lowering operation of the intakestoplogs. The standing space shall be provided with an interior light and fan andshall be covered with Hand Railing and padded operator seat. The floor should belined with insulating mats.

A digital indicator shall be fitted in the operator's cabin to show the position of theraking machine in operation as well as lifting/lowering of stoplogs.

Special considerations shall be given to the arrangement of the rake when itshighest position so that the load can be easily discharged into the trash disposaltrolley.

It shall not be possible to travel while hoisting or lowering the trash rake as well aswhile lifting or lowering the stoplogs. Limit switches shall be provided at bottomends of rail track to indicate end positions.

(e) Instruction Plates:

All gauges, meters, instructions shall have dials or scales calibrated in metricsystem units. All name plates, instruction plates, warning signs and any markingwhatsoever on the equipment and its parts and accessories shall be in Englishlanguage, using the idioms and words meaning in current use in India. All markingsto be used shall be submitted to the Engineer-in-Charge for approval before theequipment is marked or labeled. Bumpers Spring/hydraulic bumpers shall beprovided at both ends of the cleaning machine. The bumper shall consist ofsuitable spring, steel cylinders and the rams and shall be fastened securely to thetrucks.

The spring bumpers shall be capable of bringing the machine to a gradual stop in adistance of not more than 200 mm when travelling in either direction at rated speedwhile power is cut off, without producing excessive stresses or damage in the

structures. The bumper stops shall be of cast/structural steel accurately mounted tomeet the bumpers squarely. The centre line of the contact shall not be lower thancentre line of the wheel carriage. The design of the bumpers shall provide aminimum factor of safety of 6.

3.4 Mechanical Features

(a) Long Travel Mechanism:

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The long travel mechanisms shall be mounted on both the end carriage and shallgenerally consist of a motor, an electromagnetic brake, gear reductions, shaftingand couplings on each end carriage. One number wheel assembly on both endcarriages shall be powered by independent long travel mechanisms, having asynchronized operation through control equipment to avoid any skidding. In orderto have a perfect movement of the machine, the wheels shall be of double flangetype. All axles shall be forced fitted with roller bearings and wheels shall beprovided with high pressure grease lubrication. All wheels shall be interchangeableand designed to facilitate the removal of wheels, bearings from the frames.

(b) Tilting Front Panel:

The machine shall be designed as a heavy duty frame structure. On the upstreamside of the machine the tilting panel rake shall be mounted on bronze bearings.The rake should be able to run on sloping Trash racks. It shall take the debris intorakes and move upwards. After reaching the highest position, the tilting panel shallpivot inwards. The rake will open to empty the trash into the trash debris trolley.The tilting panel will allow a hindrance free emptying of the rake. The movement ofthe whole table shall be effected by means of a hydraulic cylinder. The tilting panelshall be held in two maintenance free pendulum bearings. Alternatively, a suitableapron shall be furnished integral with rake head for supporting the debris in therake head. In the highest position of the rake head, the rake head and apronassembly shall swing inward to the trash trough where the rake head shall open tounload the debris.

(c) Trash Rake:

The rake will allow the handling of oversized trash (Tree trunks). The trash rake willbe mounted on the rake carriage which runs on four wheels. To avoid unnecessarywater transportation, slots shall be provided in the rake to drain out the water fromit. The rake will be of welded steel construction with stainless steel teeth forcleaning the rack bars from inside. A rake opening rope leading over a pulley, willopen and close the rake. This movement will be actuated by hydraulic cylinder. Therake carriage will be lifted and lowered by two ropes, which will be running over thedeflection pulleys to the rake winch. The rake carriage wheels will run in the guide.

The shape of cleaning rake is in compliance with a tested design for high watervelocity and capable of cleaning rakes even in case of thick deposited material.The toothed blade shall be of adjustable & replaceable type. The bearing usedshall be maintenance free and can be lubricated. The axles/pin shall also be madeof stainless steel.

(d) Protecting and surveillance devices:

Following minimum devices shall be provided on the machines.

Overload and slack rope switch

Duty and emergency limit switch at lifting gear

Limit switch for travelling gear

Motor protecting and thermister monitoring

Minimum oil level detection and filter surveillance on Hydraulic system

Minimum and maximum pressure surveillance on hydraulic system(pressure relief valves)

Over temperature monitoring on hydraulic system

Timer for various travelling/cleaning operation (surveillance of operationtime)

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Alarms and flashing lamps

Emergency Closing at cabin and at legs.

Emergency push buttons (on control cabinet and hand held remote controlunit)

Pressure rollers at the rope-winding area.

Protective devices shall be designed for fully automatic operations. TheBidder shall propose additional protection schemes considered necessaryfor safe and reliable operation of the TRCM Unit.

(e) Rake Winch:

The rake winch shall be provided underneath the tilting front panel. The rope drumof the winch shall have grooves for the winding of the ropes.

The gear motor equipped with helical gear wheels shall be provided for the drive ofthe winch. The motor shall be tropical insulated. The brakes of the winch shall beloaded disc type having DC discharge solenoid. The drives shall be formed byTEFC squirrel cage type motor (alternatively frequency controlled).

(f) Hydraulic Power Unit:

The hoisting unit is driven by hydrostatic drives powered by the central hydraulicunit shall be located at a suitable level and shall include a stainless steel, doublepowder-coated reservoir (preferably RAL 7016 outside); an electric motor(preferably TEFC squirrel cage induction motor) driven gear pump; a manualpump; automatic controls; pressure relief, check, flow control, and directionalcontrol valves; oil pressure and temperature gauges; fluid level switch; filters andstrainers; stainless steel piping; and all accessories, appurtenances, and wiringrequired to provide an operational fluid power system for the operation of the trashrake according to the requirements of these specifications. The piping to the drivesis made of stainless-steel hydraulic pipes and stainless steel fittings. The hydraulicpower unit shall be designed conforming to relevant Indian/ International Standard.The hydraulic oil (preferably ISO VG 68) shall be environmentally friendly,biologically degradable and suitable for ambient condition prevailing at siteincluding high temperature and low altitude with suitable arrangement for heatingthe oil.

3.5 Electrical Features

(a) Illumination System:

The trash rake shall be equipped with a lighting system as follows:

400-W high pressure sodium lamps for gantry travel headlights one oneach corner of the structure illuminating the rails ahead of the gantry.

Two 400-W lamps, of a type selected by the Contractor, for illuminatingthe working area of the raking operation.

Sufficient incandescent lighting to properly illuminate the operators cab,cab access, ladders, and walkways.

Position lights and reflectors at each corner or protrusion of the gantrystructure at deck level.

A portable hand lamp with suitable length of flexible cable.

(b) Electrical equipments and controls:

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The full automatic operation, setting to cleaning position, course of cleaning cycleand machine monitoring shall be controlled by programmable logic controller(PLC). The entire electrical control equipment is located inside a control cabinetmade from galvanized and painted carbon steel (preferably RAL 7016 outside).The control elements are located on the outside of the switch cabinet. The power issupplied by means of a spring-loaded cable reels. Due to the length of the railtrack, the power point is assumed to be fed at equidistant between both ends of therail track.

3.6 Gantry Crane for lifting Intake Stoplog

(a) Brief Description

For lifting/placing stoplog (existing) for maintenance purposes, a dedicated RopeDrum Hoist with Two Drums Driven by Electric Motor gantry crane with a rotatorand a long gripper of approximately 15MT capacity is required separately to TRCM.It shall be located either at the left or right hand side of the machine designed totraverse in the existing rail tracks. It shall be operated directly at the control stationbeside the crane. Optionally, there shall also be the arrangement to operate thecrane by a hand held remote control panel for better view to the working area. Thisshall confirm with the technical datasheet as provided in Technical Data Sheet.

The braking system shall be DC operated solenoid electromagnet.

The Gantry Crane for lifting of Intake Stoplog shall have 15MT capacities and itshall be able to lift or lower the existing intake stoplogs up to the height of 22 m(from still elevation of 513.80 m to EL 535.794 m) clear from the surface so thatstoplog can be moved from one location to other. The lifting beam shall fit into theexisting lifting lug of intake stoplog. Gantry shall be designed for smooth, accurateand precise operation along the length of the rails. The motion of the gantry shallbe controlled by motor of rated capacity. The opening between the gantry legs shallhave sufficient space to house trash disposal trolley. The gantry shall be providedwith bumpers, and hold-down devices, which should fit over the rails to prevent the

gantry assembly from tipping. The hold-down device shall be designed for themaximum unbalanced force, including maximum lift on the rake head, seismicloading and shock loads during both raking and lifting/lowering of stoplog. Thegantry shall remain stable during all operations by rake head and lifting/lowering ofintake stoplog. Proper anchoring arrangement shall be provided to take care of thetrash-raking machine during storm condition.

(b) Control Panel for Lifting Mechanism of Intake Stoplog

The control panel for the lifting and lowering of the intake stoplog mechanism shallbe in a separate panel as part of the supply of the Gantry Crane purpose. Thecontrol panel shall be neat and wiring carried out as per the highest standards andpractices. Necessary contactors, switches and other components mountings shall

be suitably located so as to ease the maintenance and replacement. Necessaryferrules, labels and texts for each and every component shall be printed / written asper the best industry standards and practices. As the control panels shall beinstalled in the machine, appropriate degree of protection shall be given.

(c) Lifting Beam for Intake Stoplog

The lifting/lowering beam with automatic engaging and disengaging throughcounter weight operated linkage mechanism shall be provided. The counter weight

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lever shall be placed in designated location corresponding to "engaged" or"disengaged" operation.

(d) Lifting/Lowering Mechanism of Stoplog

The lifting/lowering function of the stoplog shall be through the dedicated Gantry

Crane having rope drum hoist driven by adequately rated capacity motor. Suitablearrangement for balancing tilting motion of stoplog shall be provided. Suitableelectromagnetic and thruster brakes shall be provided for braking operations. Thehoist motion shall stop automatically at the two extreme positions or in caserequired anywhere in between the top and bottom as desired by the operator. Theoperating speed shall be 2 m/min.

3.7 Log Grappler

For retrieving long/heavy logs or other bigger floating items and carcasses from the

water surface, a hydraulic operated 3 MT capacity Jib Crane with rotator and gripper is

required attached to TRCM. This shall confirm to the technical datasheet as provided in

Technical Data Sheet Item 3.

The log grappler shall be mounted to the left or right of TRCM having integrated or

independent operation control system. If the Jib Crane cannot be mounted to the

TRCM, the Bidder can propose a separate movable Jib Crane of the same

specifications considering the space constraints in the operating deck.

There shall also be the possibility to operate the crane by a hand held remote control

panel for better view to the working area.

3.8 Electrical Scope of Work

The scope of work will be on turnkey basis and include all the works required for project

implementation, but not limited to the followings.a) DB at shop floor level

b) Junction Box (JB) at Gantry

c) Incoming Cable from DB to JB with cable tray and other accessories.

d) Crane Electrics

The scope of work also includes sectionalizing Isolator (MCCB), all types of cables,

complete system including supporting insulator and compensation equipment along the

complete length including its connection arrangement with multi-run incoming cable at

end in the shop and main current collectors on the crane and all other electrical items

beyond the main current collector on the crane , i.e. main current collector, power

disconnecting switch on bridge platform, protective and control switch gear, motors,

control and brake panels, resistors, brakes, limit switches, all power and control cables,

cable trays, cable accessories, socket outlets, lighting distribution panel, lighting fixture

with lamps, festoon cable system, master controllers, indicating lamps, push buttons,

pendants, earthing materials etc.

The Scope of work also includes complete assembly and wiring of cranes including

load testing at site, earthing, erection and testing and commissioning of all electrical

equipments, supply of all commissioning spares.

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All sundry erection materials required for installation and connecting up of electrical

equipment with cable laying and fixing accessories shall be included in the scope of

supply by the Bidder. Minor civil work like chipping, digging surface finishing etc

required for completion of work will be in the Bidders scope. Any other work notforeseen at this stage, but may become necessary during erection, testing and

commissioning of the equipment shall be included in the scope of supply by the Bidder.

3.9 Cable Specifications

GENERAL

This specification covers the Design, Manufacture, Factory test, Supply, Delivery, Fieldtest and Installation of all Power, Control and Instrumentation cables required for the entireproject.

EQUIPMENT TO BE FURNISHED

The following cables shall be furnished in accordance with specification:

a) Control and Instrumentation cableb) Power Cables

The Contractor shall be responsible for estimating and supplying the quantity of varioustypes and sizes of the cables. In course of actual execution if it is found that additionalcross-sections, types or quantities of cables are required than those indicated in hisproposal, the same shall be supplied without any additional charge to the employer.

DESIGN REQUIREMENTS

3.9.1 Control and Instrumentation Cable

(a) General

All control and instrumentation cable shall be 600 V grade as per IEC multiconductor, color coded, PVC insulated armored cable. Each multi-core cableshall have not less than 20 percent or 4 spare cores whichever is the greater.

(b) Conductor

Copper conductor shall be stranded circular non-compacted copperconductor of minimum cross-section of 2.5 sq.mm.

(c) Insulation

The electrically and thermally stable PVC insulation shall be extruded ontothe conductor so as to prevent contamination and voids in the insulation.

(d) Assembly

Multi-conductor cables shall be assembled in accordance with applicable IECstandard.

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A flame reparative binder tape may be used underneath the overall jacket ofmulti-conductor cables, if required to achieve the desired flame retardativecharacteristics. Tapes, if used, shall be non hygroscopic.

(e) Jacket

The cable core assembly shall be covered with a flame retardative andresistant jacket, which is free-stripping from the insulation.

The overall jacket shall be clean, dry, and free of grease and shall be suitablefor ink or paint application.

Cable jacketing and the interstices within the jacket shall be free of water.Evidence of water shall be ground for rejection of the cable.

(f) Anti- Termite Covering

Anti-termite protection shall be applied to the cable and shall consist of eithera non-magnetic metallic barrier or layer of nylon sheathing.

(g) Identification

Each cable shall have a printed legend on the overall jacket, with themanufacturers name, voltage class, the number and size of conductors, anda unique number or code indicating the production run or batch. Theidentification shall remain legible for the life of the cable.

3.9.2 Power Cables

The Cables should be 600V grade Polyethylene insulated and PVC sheathed. LowVoltage AC Power systems will be solidly grounded neutral with Phase to PhaseVoltage level of 400V and Phase to Neutral Voltage 230V. The size of theconductor shall not be less than 4Sq.mm.for lighting and 4Sq.mm for Power.

(a) Conductor

The Conductor shall consist of Annealed Copper Conductor, complying withrelevant IEC. The Cable is intended for use at Outdoor condition withoperating Temperature not exceeding 75DegC.

(b) Insulation

The Electrically and thermally stable Polyethylene Insulation shall be extrudedonto the conductor such as to prevent contamination and voids in theinsulation.

(c) Current Ratings

The Contractor shall state the maximum continuous current rating for thecable and conditions of the installation for Power cable.

(d) Jacket

The cable core assembly shall be covered with a flame retardative andresistant jacket, which is free-stripping from the insulation. The overall jacketshall be clean, dry, and free of grease and shall be suitable for ink or paint

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application. Cable jacketing and the interstices within the jacket shall be freeof water. Evidence of water shall be ground for rejection of the cable.

(e) Identification

Each cable shall have a printed legend on the overall jacket, with themanufacturers name, voltage class, the number and size of conductors, anda unique number or code indicating the production run or batch. Theidentification shall remain legible for the life of the cable.

3.9.3 SPECIAL REQUIREMENTS

Small cut piece lengths of cables will not be accepted. Cables up to 500 meters inlength or as approved by Employer shall be of one length shipped in a drum ofadequate size. For higher quantities, multiple lengths/drums may be shipped subjectto the approval of Employer.

3.9.4 DRAWINGS, DATA & MANUALS

The following information shall be furnished along with the Tender.

Manufacturers leaflets giving constructional details, dimensions and characteristicsof different cables.

Current rating of cables including de-rating factor due to grouping, ambienttemperature and type of various installation.

Write-up with sketches illustrating the manufacturer recommendation for splicing,jointing and termination of different types of cables.

Type test report of all types of power, control and instrument cables. The Tenderershall clearly describe the type and routine tests.

Drum length for each type of cable.

3.9.5 TESTS

Routine and Design Tests

The following tests shall be included in the routine test by the manufacturer at thefactory as minimum requirements for this specification: Design Test should becarried out by the Accredited Test Laboratory.

a) Construction inspectionb) Conductor resistance testc) High voltage test

d) Insulation resistance teste) Physical and aging test for insulation and jacket

Field Tests

After installation at Site, cables shall be subjected but not limited to the followingtests:

a) Measurement of insulation resistanceb) DC dielectric test

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3.9.6 PERFORMANCE GUARANTEE

The performance figures quoted on schedule of Technical Data shall be guaranteedwithin the tolerance permitted by relevant standard and shall become part of theContract. In case of failure of the cables to meet the guarantee, the employerreserves the right to reject the equipment. The Contractor shall have to rectify thedefect at no extra cost to the employer and without delaying the commissioningschedule.

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4. Detailed Technical Specifications of Silt Flushing Gate

4.1 Description and Design Criteria

The overall arrangement of the equipment covered under the scope of supply shall bein accordance with these technical specifications.

i) Design stresses

For embedded parts : Wet & inaccessible condition.

For components of Gates : Wet & inaccessible condition.

Reference of IS codes : IS: 9349 (latest)

a) Hoist : Hydraulic hoist of adequate capacity.

b) Lifting & Lowering speed : 0.5m / min.

Operation: The gate shall be operated under flowing water

conditions and shall also be used for regulation.

Permissible deflection : Span / 2000Permissible bearing and

shearing stresses in concrete

:As per IS: 456 (latest)

Grade of concrete to be used.

1st

stage concrete : M 20

2nd stage concrete : M 25

Min. thickness of skin plate : 10 mm

Min. thickness of track plate : 10 mm (after machining)

Min. thickness of seal seat : 10 mm (after machining)

Type of seal : Metallic seals

Design Parameters

The design requirements for the silt-flushing duct gate are given below:

Type of gate : Vertical

No. of openings : 1

Size of opening : 2000 mm x 1000 mm

FRL : EL 531 m

Design Head : 6.09 m

Water Discharge : 103.84 x 3 cubic m/sec

4.2 Components of Silt Flushing Gate

4.2.1 General

All the gates for silt flushing tunnel shall consist of skin plate, supported onvertical stiffeners which in turn rest on horizontal girders. The horizontal girdersare mounted on end girders which transmit the hydrostatic pressure to trackgirders through the bearing pads. The gate shall be designed in accordance withIS: 9349 for following loads:

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a) The full hydrostatic pressure on upstream side of the gate with water levelrising to FRL and the gate is closed.

b) Total applied hydrostatic, hydro-dynamic and frictional loads when the gatesare raised and lowered with the upstream water level at FRL / MWL.

4.2.2 Skin Plate

Skin plate and stiffeners shall be designed together in a composite manner. Skinplate shall be checked for the following two conditions:

a) In bending across the stiffeners or as panels andb) In bending, co-acting with stiffeners.

4.2.3 Horizontal Girders and Stiffeners

The horizontal girders may be so spaced that all the girders carry almost equalloads as far as practicable. The girders shall be designed considering the fixity atend vertical girders. Horizontal girders shall be checked for shear at the pointswhere they are supported by end vertical girder. The spacing and design of the

vertical stiffeners shall be governed by relevant provisions in IS: 800-(latest).

4.2.4 Seals

Metallic seals shall be fixed to the gate leaf by means of counter sunk screwsmade of stainless steel / corrosion resistant steel or by welding. The screws shallbe designed to take up full shear likely to develop during raising or lowering thegate under maximum head of water between the seal and bearing plates. Thescrews shall be adequately tightened to a constant torque and locked by punchmark. Minimum threaded length equivalent to one-and-half times the diameter ofscrews shall be screwed to ensure against their loosening under vibrationsduring operations.

4.2.5 Seal Seats, Seal Bases and Sill Beams

The minimum thickness of seal seats shall be 10 mm after machining unlessotherwise stated. The seal seats shall be stainless steel conforming IS: 1570-(Part-5)-Latest.

The seal seats shall be welded to the seal seat bases. The seal sent seat shallbe finished smooth to triple delta surface finish.

The seal seat bases shall be made of plate or any structural section on which theseal seat is fixed.

The sill beam shall be provided with the stainless steel plate as bottom seal seat.

The surface of the sill beam shall be machined smooth.

4.2.6 Guide Shoes

Guide shoes / plates shall be provided to the sides of Gates to limit the lateralmotion or side ways of the gate to not more than 3 mm in either direction. Shoesshall be adjustable and removable. These shall slide on guide of structural steel.The permissible stresses in design shall be given in Appendix A of IS: 4622.

4.2.7 Anchor Bolts or Anchor Plates

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Anchorages shall be provided in the 1st

stage concrete with suitable blockoutopenings to hold the 2

ndstage concrete shall be with double nuts and washers.

The anchor bolts shall be of minimum 16 mm diameter.

4.2.8 Tolerances

The tolerances for embedded parts and components of gates shall be as perapplicable standards. The distance between the guide plates shall be true withina tolerance of 3 mm.

4.2.9 Body Bonnet & Bonnet Cover

Body: The body shall be adequately ribbed to provide proper anchorage withsurrounding concrete. Guides shall be fixed to body for guiding the gate.

Bonnet: Bonnet will have flanges at the bottom for being bolted to the body andon the top for the bonnet cover. It will be of same material as of body and shallbe adequately ribbed for proper bonding with surrounding concrete. Guide shallalso be fixed in continuity of the guides fixed on the body for guiding the gate.

Cover: The bonnet cover shall be provided to seal the gate slot and shall providesupport for the hoist in case hoist is mounted directly over the bonnet. It shall bedesigned for full hydrostatic pressure and hoist capacity if hoist is mounteddirectly over it.

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5. Detailed Technical Specifications of Trash Rack Panels

5.1 Design Parameters

Nos. of opening / Complete Sets required : 3

Type of Trash Rack Panel : Fixed

Size of each Trash Rack Set : 6 m (w) x 13.2 m (h)

Inclination : 80o

(with the Horizontal)

Sill Level : 517.294 m asl

Degree of Log Jam : Min 50% (to be defined in tender documents)

Total nominal discharge : 103.84 x 3 m /s

Deck Level : 535.794 m asl

Maximum operation water level : 531.00 m asl

Top of Trash Rack level 526.20 m asl

Clear space between trash bars : 75-150 mm (to be confirmed by turbine supplier)

Trash bars thickness : ~ 10 15 mm

Cleaning and panel removal : By Trash Rack Cleaning Machine

5.2 Design, Material and Workmanship, Requirement of Components

5.2.1 Design

The trash racks shall be designed in accordance with the applicable standards.

Special attention shall be paid to the problems of flow-induced vibration andfatigue in the design of the trash racks.

5.2.2 Loading Conditions

Unless otherwise specified the following loading conditions of the trash racksshall be considered:

a) Loading Case A:

Temporary loads during handling, transportation, assembly and erection, forwhich on permanent deformations and detrimental stresses shall occur.

b) Loading Case B:

Normal loading conditions: dead weight of trash racks and water head.

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c) Loading Case C:

Exceptional loading conditions: Further to the normal loading conditions(Case B), the trash rack panels and beams shall be able to resist withoutdamage the dynamic forces due to an earthquake with an acceleration of0.19 g, in any horizontal direction and two thirds the horizontal co-efficient invertical directions.

5.2.3 Structural Computation and Safety Factors

Structural computations shall be performed in accordance with applicablestandards.

Whichever computation methods and standards are applied, the safety factorrelated to the yield of the steel shall not be less than the following values:

LOADING CONDITIONS

Normal Exceptional

Compression and compression due to bending, when

stability problems are involved.

1.7 1.30

Tension and tension due to bending. 1.5 1.15

Combined bearing bending and shear stresses. 1.3 1.10

Shear (ultimate shear stress = 1/3 x shear stress. 1.5 1.15

5.2.4 Flow Induced Vibration on Trash Racks

The trash racks shall be designed to prevent detrimental vibration induced by theflow through the trash rack.

5.2.5 Flow Velocity

The average flow velocities shall be calculated for normal and exceptional flow

conditions across the effective trash rack area.

5.2.6 Safety against Vibration

General: The laterally unsupported lengths of trash racks bars and othermembers shall be such as to assure that the fundamental natural frequency ofrack bars or other members when submerged in water will be higher than thevortex shedding frequency of the flow.

When calculating the vortex shedding frequency of flow the following data shallbe used:

a) Flow velocity equal to 3 m/s.

Natural frequency of rack bars:

When calculating the fundamental natural frequency of rack bars, fixedsupports shall be assumed only if the horizontal rack stiffener plates arenotched and at least 50% of the rack bar depth is lodged in the stiffenerplate, the rack bar being welded all around to the stiffener plate.

If less than 50% but more than 30% of the rack bar depth is lodged in thestiffener plate, 50% fixity shall be assumed.

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If less than 30% of the rack bar depth is lodged in the stiffener plate, the rackbars shall be assumed simply supported.

5.2.7 Safety Factors against Vibration

The fundamental natural frequency of any rack bar or other member shall not beless than 2.5 times the vortex shedding frequency.

5.2.8 Material

a) Structural Steel

In accordance with applicable standards

b) Welding Materials

All welding materials used for the work shall be of the highest quality andrequirements of the specifications and the applicable standards (AWS).

c) Bolts

Where easy dismantling of bolted connections shall be ensured, followingbolt materials shall be used:

Stainless steel bolts when the threads are provided in the base materialitself.

Stainless steel bolts and nuts when bolts and nuts are used.

However, due attention must be paid to the danger of electrolysis andcorrosion where stainless steel is in contract with normal structural steel.

d) Auxiliary and Mechanical Parts

The Contractor shall state in his calculations and on the drawings andmaterial list the standards and types of material be intends to use.

5.2.9 Minimum Dimensions

Minimum dimensions, without regard to stress considerations, shall not be lessthan the following, unless otherwise specified.

Material Thickness Minimum

Trash Rack Bar 12 mm

Horizontal stiffener 30 mm

Plate thickness on any structuralmember except webs of rolled shapes

10 mm

Webs of rolled shapes 8 mm

Embedded metal with exposedsurfaces

12 mm

Completely embedded metal 10 mm

Diameter of bolts or screws on trashrack structures

16 mm

Diameter of adjusting bolts between 16 mm

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frame or embedded part and weldingpad

5.2.10 Workmanship

a) General

All work shall be performed by skilled workers and completed in a thoroughworkmanlike manner, following the best modern practice in themanufacture of high-grade equipment.

All work shall be carried out under the technical direction of a qualified andexperienced engineer and shall be continuously supervised by personssuitably trained and experienced in the fabrication of similar steelstructures.

Fabrication, welding and erection shall be performed with extreme care,not only from the point of the quality of the material and the adaptation ofthe difference pieces together, but also from the point of view of theirappearance and their finish.

Fabrication and welding techniques and details shall take into account therequirements for structures subject to fatigue.

On account of the large size of some of the trash racks, fabrication andassembly may be carried out at a field workshop, to be installed by theContractor. The trash racks shall consist of flat panels formed by steel barsand flat stiffeners, supported by main steel beams. The various parts andsections shall be of welded construction, and assembled by means of boltson site.

b) Welding

The contractor shall develop a detailed welding procedure showing thesequence and technique to be followed in the fabrication of the trash rackpanels, main girders and frames. Preheat shall be provided when andwhere necessary, and the welding shall be carefully controlled to minimizeshrinkage stresses and distortion.

The sequence of tack welding and welding shall be shown clearly on theContractor drawings prior to submitting them to the Engineer for review.

The seams shall be continuous and welded from both sides, using theelectrical are welding method. For all parts subject to fatigue, the weldfillets shall be continuous over the whole length of the intersection betweenadjacent pieces; they shall be of smooth appearance, without notches,

crackers or abrupt interruptions, and they shall be ground smooth whenand where necessary. Angles fillets shall have a concave section.

c) Manufacturing in the Shop

Sheared or flame cut edges of elements which carry computed stresses orsubject to fatigue shall be planned or ground smooth to such depth that allnotches, cuts and projections are eliminated, but at least 3 mm.

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All work shall be performed so as to secure proper matching of adjoiningunfinished surfaces. Where there is a large discrepancy between adjoiningsurfaces, same shall be chipped and ground smooth, or machined, to ensureproper alignment. Unfinished surfaces shall be true to the lines anddimensions shown on the drawings, and shall be chipped or ground so as tobe free from projections and rough sports.

The surface finish of all parts and components shall be in conformity with therespective strength, fit and service requirements. Surfaces to be machine-finished shall be indicated on the shop drawings by corresponding symbols.

Machining of renewable parts shall be accurate and to specific dimensionsso that replacements made to drawings size be readily installed. Like partsand spare parts shall be interchangeable. Drilled holes for bolts shall beaccurately located and drilled from templates or match drilled.

d) Preassembly

The trash-rack shall be shop assembled and checked for dimensions,tolerances and accuracy of alignment. Any error or misalignment discovered

shall promptly be corrected.

Built-in parts shall be assembled too. Frames shall be checked fordimensions, tolerances and accuracy of alignment.

Parts shall be clearly match marked before disassembly for transportationand any error or misalignment discovered shall be promptly corrected.

e) Assembly and Erection at the Job Site

The assembly and erection of the various trash rack parts and sections shallfollow the methods and sequences submitted to the Engineer for review.

5.2.11 Tolerances

All important tolerances, particularly those of machined parts, shall be marked onthe drawings to be submitted. They shall be determined by the Contractor in sucha way that the operating condition will be maintained at low wear and tear.

Forcing of bolts, due to erection inaccuracies shall not be lead to overstressing.The erection tolerances are to be determined according to these considerations.

5.2.12 Corrosion Protection

Corrosion protection, cleaning and painting shall be done in accordance withapplicable standards.

Trash rack bars and girders shall be hot dip galvanized or painted according topaint System B (Epoxy Painting). The Contractor shall adequately protect thepanels during erection to avoid damages to the painting and galvanizing. Shouldany damage to the corrosion protection be found in the final inspection afterinstallation, the Contractor shall remove the damaged panels, carry out thenecessary repairs and install them again, at no cost to the Employer.

5.3 Specific Requirements of Components

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5.3.1 Embedded and Fixed Parts

Anchor bolts and plates shall be placed in such a way and at such intervals so asto ensure easy alignment and true positioning.

5.3.2 Trash Rack Panels

The maximum length of rack bars between lateral supports and / or stiffenersshall be such as to avoid detrimental vibrations.

Trash rack panels showing undue deformations after assembling and weldingshall be clamped in straight position and stress-relieved.

5.3.3 Inspection and Test

a) Test Reports

Test Certificates or test reports shall be made and submitted to the Engineerfor all test performed.

b) Material Test

For all materials, which are of significance for the duration and the performanceof the constructions, acceptance certificates according to EN 10204/DIN50049,

Before starting with the fabrication, the Contractor shall submit the saidcertificates to the Engineer.

c) Shop Test

Qualification of Welders

Prior to commencing any production welding, each welder and weldingoperator assigned to the work shall be qualified in accordance with Section IXof the ASME Code.

Welding Procedure Test

Prior to commencing production welding, all weld procedure qualification testshall be carried out in accordance with Section IX of the ASME Code.

Dimensional Checks and Visual Inspection

Dimension checks shall be performed on all sections of the trash racksespecially when close tolerances of the difference sections of trash racks are

involved. If the dimensional checks show discrepancies in measurement whichmay affect the fit, assembly or dismantling of the respective sections, samehave to be corrected correspondingly. Such correction or modification shallimpede in no way the reliability of operation and shall be performed only withthe agreement of the Engineer. If the correction or modification cannot becarried out in accordance with the terms mentioned above, subject part shallbe rejected.

5.3.4 Corrosion Protection Checks

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The corrosion protection will be checked by the Engineer. Examination willinclude:

cleanliness of the cleaned surfaces.

thickness and adhesion of coats.

quality of the materials applied.

The thickness of the coats shall be checked at about 2 check points per squaremeter. For the acceptance, the guaranteed thickness of the coating shall bedecisive and not the number of coats applied.

5.3.5 Trial Operation

The Trial Operation for the Intake Trash Racks shall start with the Trial Operationof the corresponding generating unit.

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6. Detailed Technical Specifications of Civil Desilting Structure andremoval of Silt

6.1 Excavation

6.1.1 Scope

The item shall include clearing site, excavation to the designed section of thematerial, their sorting, and their depositing either in soil banks or in bank work asspecified including all lead and lifts.

The owner shall ensure that intake area is dewatered and completely driedbefore handing over site to the Contractor. The site of excavation shall also beclear of all grass vegetation, fencing, bushes, trees, etc before handing over tocontractor. Any roads or ramps required shall be provided by the owner.

The details scope of work for excavation shall be as below:

i) Setting out works profiles etc, accordingly to plan, or as directed by Engineer

In Charge, and setting up bench marks and reference marks

ii) Providing and subsequently removing, shoring and strutting if and whennecessary

iii) Necessary protection including all labour, materials and equipments toensure safety and protection against risk of accident

iv) Supply of facilities for inspection and measurements at any time to theconcerned officials

6.1.2 Line Out

All materials such as peg, bamboo and templates for marking out slopes andlabor required for line out shall be provided by the contractor at his own cost.

Before starting the work, the Contractor shall have to sign the field books andplans showing the working longitudinal sections and cross section of the portionsto be excavated.

The materials available from all excavation and remaining surplus after use onthe work can be used by the Contractor free of cost provided these materials areused solely for the specific contract work.

6.1.3 Payment Line (Pay Lines)

The minimum excavation line is true line within which no unexcavated portion ofany kind shall be allowed to remain. Payments shall made for the work done asper the minimum excavation line.

6.1.4 Disposal of Excavated Material

The disposal of all materials from excavation shall be as per approved disposalplan or instructions of Engineer-In-Charge regarding the location and deposition ofstock piles, spoil banks or embankment.

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All material excavated shall be the property of the owner and shall be deposited asdirected by the Engineer In Charge.

6.1.4 Mode of Measurement

Classification of the excavation will be made from the cross sections visible at hesides of the excavation and from measurements of ridges which shall be left at20 m or less as directed by the Engineer In Charge, which must be removedimmediately after the final measurements have been taken except when ordersare especially given to retain these ridges.

As a rule, measurement of the excavated material on stacks shall not bepermitted. However when it is not possible to get a record of the excavatedmaterial in cross section, measurement of the excavated material on stacks maybe permitted in writing.

6.1.5 Preparing and Testing of Foundation

Scaling and Trimming of Foundation

After rough excavation to the required depth is completed, scaling andtrimming operations for removal of all pieces loosened during excavationshall be carried out to the satisfaction of the engineer in charge

Final Finished Surface of Foundation

The finally prepared foundation shall present a rough surface in cross sectionto give added resistance to sliding. All smooth surface shall be roughenedartificially to give a good bond. The surface shall be free from steep angleand the edges of benches shall be chamfered and flattened.

Testing for Soundness

The finally finished foundation rock shall be tested by striking with a heavyhammer and if loose portion of foundation rock is revealed by hollow sound,it shall be excavated further till a clear ringing sound is obtained.

Excavation Outlines and Paylines

All excavation shall be performed in accordance with the lines, grades,levels, and dimensions shown I the drawing or established by the Engineer InCharge.

6.2 CEMENT CONCRETE:

6.2.1 SCOPE OF WORK:

The work covered by this item shall consist of:

i) Furnishing all materials, equipment and labor for the manufacture,transport, placing and curing concrete and performing all the functionsnecessary and ancillary thereto including the concrete to the requiredshape as per drawing.

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ii) Installation of all embedded parts stands included in the rates. Noextra payment will be made for the installation of this embedded metalwork or for delays or for interruptions arising there from.

iii) Providing and removal of all from work comprising of furnishing allmaterials equipment and labor for the manufacture, transport,erection, keeping in place with necessary fixtures and supports oiling

etc. complete.iv) Necessary sampling and tests for materials and concrete.v) Compensation for injury to person and damages to work or property.

6.2.2 QUALITY:

The sand shall consist of hard, dense, durable uncoated, gritty materialobtained from rock fragment, it shall be free from injurious amounts ofdust lumps, soft and flaky particles, shale, alkali organic matter, loam,mica and other deleterious substances. The maximum percentage ofdeleterious matter in sand as delivered for use in mortar shall not exceedthe following values.

PERCENTAGE BY WEIGHT

Materials passing 75 micron I.S. Sieve

(00029) 3 PercentShale 1 PercentCoal 1 PercentClay lumps 1 PercentTotal of other deleterious substances such as Alkali,Mica coated grains, soft and flaky particles 2 Percent

The sum of percentages of all deleterious substances shall not exceed5% by weight. The sand shall be free from injurious amounts of organicimpurities. Sand procuring a colour darker than the standard in thecalorimetric tests for organic impurities shall be rejected. If the impuritiesare beyond the acceptable limits stated above, the sand shall be washedor otherwise cleaned to the entire satisfaction of the Engineer-in-Chargeat the cost of the Contractor.

6.2.3 COARSE AGGR