mazagon dock limited mazdock modernisation...

A COMPANY OF

MAZAGON DOCK LIMITED

MAZDOCK MODERNISATION PROJECT

Contract No. MMP/01006/03

DETAILED PROJECT REPORT

FINAL ISSUE

Volume 1, Rev 1, 21st

November 2003

HASKONING NEDERLAND BV

MARITIME

A COMPANY OF

Mazagon Dock Limited

Project name Mazdock Modernisation Project

Document title Detailed Project Report Volume 1

Status Final Issue Revision 1

Date 21st November 2003

Royal Haskoning

Project number 3H6543

MMP Contract number MMP/01006/03

Reference 3H6543:R007

Drafted by D.S. Byrom, S R Davies, R C B Potter

Checked by P D Gallagher

Approved by P.D. Gallagher

Marlborough House

Marlborough Crescent

Newcastle upon Tyne NE1 4EE

United Kingdom

+44 (0) 191 211 1300 Telephone

+44 (0) 191 211 1313 Fax

[email protected] E-mail

www.royalhaskoning.com Internet

HASKONING NEDERLAND BV

MARITIME


Mazdock Modernisation Project

- i -

Document No. 3H6543/R007Final Issue Rev 1

November 2003


Mazdock Modernation Project 1


November 2003

MARITIME CIVIL WORKS CONTRACT – the WET BASIN

1.1 Objectives - Re-Statement

Stated simply, the primary objectives of the physical infrastructure of the Wet Basin are

as follows :

� To improve the cost efficiency and productivity of the Yard in the construction,

completion and repair of surface and sub-surface naval vessels, and of merchant

ships as applicable.

� To provide a enclosed or captive outfitting/repair haven generally for naval vessels

but also to be available for merchant tonnage when required.

� To provide a virtually constant yet controllable water level environment such that

vessels undergoing outfit/re-fit or repair are free from the daily fluctuation in water

levels due to tides, and with a negligible but assessable risk of bottom damage even

if the impounding gate is ever breached.

� To provide the necessary mechanical and electrical services in and around the wet

basin to enable efficient outfitting of vessels.

� To be robust and durable in design, requiring minimal maintenance for the design life

of the facility, expected to be more than 75 years before major structural repair is

need

1.2 Introduction

The text below describes and confirms the decisions made following the acceptance of

the design concepts as set out in the PPR. Each significant feature is numbered for

ease of reference and where appropriate, the relevant drawing number is given in the

third column.

1.3 Exact Location, Leading Dimensions and Water Levels & Depths

Wet Basin Feature Drawing No.

3H6543/DPR/

1.3.1 Exact Location of Wet Basin

The final exact location is as finally accepted in the PPR and is such

that :

The Wet Basin lies within the limits and constraints imposed by the

MbPT and CWPRS as far as can be determined accurately.

Ritchie Dry Dock is outside the Basin, and operates independently

The North Quay is aligned parallel to the outer faces of the Ritchie

Dry Dock Extension mitre gate protrusions so as to minimise

restrictions on vessel entry to Ritchie Dock. The north face of the

North Quay is set back 500 mm from this base line to allow for

fenders. The south face (deck edge) is set parallel to the north face

and commencing from the north corner of the submarine dry dock meeting face.

The south rail of the South Quay is aligned exactly with the 300 tonne

Goliath Gantry crane north rail. This then determines the exact

location of the South Quay

The East Quay setting-out is found by joining the extremities of the

North and South Quays

Setting Out:

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The Wet Basin Gate opening is set at 40 m from the internal face line

of the South Quay

The seaside face of the West Quay (South) wall is set parallel to the

West Quay (North-A) wall, but with the south east corner on a line

with the current berth extensions to Slipway No.2. The south face of

the wall, that closes onto the existing roundhead of crane track no. 9,

is set 4.0 m north of the north wall of Slipway No. 1 to allow future

construction by others of an extension to Slipway No. 1

The Basin side face of the West Quay (North-A) wall intersects the

existing sea wall at the junction with the line of the South Quay south

crane rail

The Basin face of the West Quay (North-B) wall that carries road

access to the Submarine Dry Dock gate area is set at 8.0 m from the

face of the existing East Yard boundary wall

The Basin face of the West Quay (North-C) wall that creates lay-

down space adjacent to the Submarine Dry Dock gate area is set

parallel to the face of the existing dry dock caisson gate

1.3.2 Leading Dimensions of the Wet Basin

(note : dimensions may be rounded for ease of reference)

(a) North Quay internal length = 183 m measured from the meeting

face of the existing submarine dry dock gate

South Quay internal length = 225 m

East Quay internal length including gate = 112 m

Gate opening in East Quay 31 m to permit clear opening of 30 m with

allowance for rubbing strip fenders

West Quay (North-A) internal length = 65 m

Water surface area bounded by the solid faces of the mass concrete

wall structures = 27,000 m2

North Quay overall deck width = 10.0 m , with a 5.5 m crane rail track

gauge

South Quay overall deck width = 16.5 m with a 10.0 m crane rail track

gauge

East Quay (North) and East Quay (South) overall deck width = 14.0

m

West Quay (South) overall deck width = 12.0 m

West Quay (North-A) overall deck width = 12.0 m

West Quay (North-B) overall deck width = 8.0 m

West Quay (North-C) overall deck width = 17.0 m

Closure Wall overall deck width = 5.0 m

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1.3.3 Water Levels and Water Depths

The finally agreed water levels and water depths associated with the Wet Basin will be

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Level to CD

in metres

Design nominal finished level of Wet Basin decks (N, E, S) + 7.000 CD

Design nominal finished level of West Quay decks approx. + 6.500 CD

Design nominal finished level of Lead-in Jetty Dolphins + 6.500 CD

Highest astronomical tide (HAT) + 5.400 CD

Highest recorded tide (HRT) + 5.380 CD

Maximum normal operating impounded level in Wet Basin + 4.500 CD

Maximum impounded level in Wet Basin controlled by

overflow pipe invert level

+ 5.500 CD

Mean High Water Springs (MHWS) + 4.420 CD

Mean High Water Neaps (MHWN) +3.300 CD

Mean Sea Level (MSL) + 2.510 CD

Minimum normal operating impounded level in Wet Basin + 2.500 CD

Mean Low Water Neaps (MLWN) +1.850 CD

Mean Low Water Springs (MLWS) + 0.760 CD

Minimum emergency water level in Wet Basin = Chart Datum +/- 0.000 CD

Lowest Recorded Tide (LRT) - 0.440 CD

Wet Basin Gate sill level - 5.000 CD

Design excavated level within Wet Basin - 6.000 CD

Design dredged level outside of Wet Basin North wall As existing

Design dredged level outside of Wet Basin South wall As existing

Design dredged level outside of Wet Basin East wall North As existing

Design dredged level outside of Wet Basin East Wall South for

full length of quay

- 6.0m CD to

existing in 20m

Design dredged level along Lead-in Jetty, south side - 6.000 CD

Approx design dredged level of Turning Circle (by Others)* - 3.000 CD

Minimum level at which impounding pumps will operate +2.5m CD

Minimum level at which equalising valves will operate +1.5m CD

Minimum level at which the gate will be opened or closed +2.5m CD

Water Depth

in metres

Maximum normal operating water depth in Wet Basin 11.5 metres

Minimum normal operating water depth in Wet Basin 8.5 metres

Emergency minimum water depth in Wet Basin 6.0 metres

* The Turning Circle will need to be relocated to suit the location of the Wet Basin

entrance. This should be done before the completion of the Wet Basin. This work is

outside the scope of the HNBV specification and cost estimates.

1.4 Dredging, Excavation in the ‘Dry’ and Contamination Issues

Wet Basin Features Drawing No.

3H6543/DPR/

1.4.1 Dredging

1. For the reasons of economy, quality of work, and flexibility in

construction including the ability to excavate in parallel with

constructing the Stage 2 works, sea dredging (involving floating

dredging plant and possibly the use of controlled explosives, see

1.4.2 below) will be limited in scope to :

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(a) dredging minimum areas for Stage 1 wall construction.

(b) dredging the Lead-in Jetty channel for 200m out toward the

turning circle.

(c) Limited dredging of the wet basin area as required for

construction operations.

(d) dredging a gradual slope from the face of the East Quay

(South) wall toward the turning circle for a distance of 20m to

minimise the effects of siltation on the performance of the

impounding pumps and discharge valves.

2. It is presently estimated from the results of the geophysical

survey and the existing boreholes undertaken in 2002, that the

quantities of ‘soft’ and ‘hard’ dredging are :-

• 56,000 m3 of ‘soft’ dredging

• 30,000 m3 of ‘hard clay’ dredging

• 70,000 m3 of ‘weathered rock dredging

3. Unfortunately the seismic survey was not able to establish the

difference between hard clay and weathered rock. The volume

of rock excavation has therefore yet to be finalised by further

geotechnical investigation. The volumes stated above are based

solely on the limited number of boreholes undertaken in 2002.

The volumes of hard clay dredging and rock dredging could

therefore be subject to significant variation.

1.4.2 Methods of Dredging

1. In dredging terms, the volumes to be excavated for this project

are relatively small. The depth of water in which dredging plant is

able to operate is also very limited across the site area. These

two factors, together with the materials to be dredged, will

probably lead the contractor to utilise a barge-mounted backactor

or a crane operated grab type dredgers.

2. This equipment will be able to remove the soft silt and the hard

clay layers and possibly the weathered rock, depending on its

strength. The dredging arisings will be loaded into a dump barge

for disposal at the MbPT dump sites.

3. Rock excavation will probably need to be assisted by controlled

blasting techniques. To prevent damage to existing MDL

waterfront structures, the peak particle velocity will be defined by

initial test blasting.

4. The need to undertake capital dredging in the approach channel

to the lead in jetty will be assessed following the further ground

investigation works discussed in section Error! Reference

source not found.. If no hard rock is found in the approach

channel above the -5.0m CD level, MDL will defer the dredging

until later.

1.4.3 Excavation in the ‘dry’




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1. Unless the actual contractors tenders show otherwise, it is the

intention to remove the large majority seabed materials from

within the Wet Basin area by land excavation techniques in the

‘dry’. The ‘dry’ condition will be achieved after the Wet Basin

Stage 1 water-retaining walls and entrance works temporary

cofferdam have been completed and the water pumped out. This

material will be dumped at sea in an approved location.

2. It is presently estimated from the results of the geophysical

survey and the existing boreholes undertaken in 2002, that the

quantities of ‘soft’ and ‘hard’ ‘dry’ excavation are :-

• 54,000 m3 of ‘soft’ material

• 40,200 m3 of ‘hard’ material

• 60,800 m3 of ‘weathered rock dredging

3. As stated in 1.4.1, the volumes stated above are based solely on

the limited number of boreholes undertaken in 2002. The

volumes of hard clay excavation and rock excavation could

therefore be subject to significant variation.

1.4.4 Contamination Issues

In respect of dredging and ‘dry’ excavation procedures will be put in

place to :-

• ensure that the materials arising from dredging activities (and

excavation) are dumped in dumping grounds or tips that are

approved by the competent Authority, the Mumbai Port Trust

(MbPT). It is currently understood that MbPT have two

designated dumping areas, one for dumping dredged materials

during ebb tides and the other for use during flood tides. The

location of and Authority for approved land-fill tipping sites is not

known at present.

Contaminated materials dumped at sea can seriously harm sea

life forms, whilst land tipped contaminated materials can

adversely affect ground water (and hence potable water) quality

• carry out tests (on samples from the proposed new boreholes) to

ascertain whether contaminants are likely to be present in the

dredged/excavated materials. Such contaminants could arise

from natural sources in the soils or probably more likely from the

activities of the shipyard over its many years of existence. Tests

will be essential to determine the levels, if any, of heavy metals

and organic compounds (eg. TBTs) in particular. The procedure

will be that appropriate tests will be undertaken and the results

discussed with MDL prior to deciding the correct course of action

to be taken.

1.5 Structural Walls

1.5.1 Re-statement of Function Drawings:

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The Stage 1 structural walls have the following functions and

requirements:

• main water retaining structures for the wet basin, to keep the water

level in the basin approximately constant

• soil retaining structures along the line of the West Quay

• provision of berthing faces for vessels

The Stage 2 structures provide the basin side part of the quay walls

and the top deck structure. This includes plantrooms, services

trenches and other deck features.

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1.5.2 Location

The setting out of the basin walls is shown on the drawings.

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1.5.3 Stage 1 Structural Walls

1. The Stage 1 Basin walls are mass concrete structures cast

underwater on the dredged rock surface.

2. Walls will be constructed within a ‘controlled environment’ to

minimise the problems associated with placing concrete

underwater. See section 1.9.2.

3. Walls will be constructed with each concrete pour being the full

width of the wall ensuring the wall will act as a monolithic structure.

4. The walls are designed to resist the following loads:

• Differential water levels

• Berthing

• Imposed deck loads

• Wave loads

• Earthquake loads

• Accidental vessel impact loads

• Silt level up to 0.0m CD

5. The founding levels of the basin walls is generally -6.0m CD.

6. The top of the Stage 1 walls will generally be 1.0m below the final

deck level. The Stage 1 walls will accommodate recesses for

plantrooms, services trenches and other features as appropriate.

7. The width of the Stage 1 walls varies and is shown on the

drawings.

8. The walls are designed to resist accidental impact loads from

vessels in the channel of size up to 3,000 dwt with velocities of up

to 0.3m/s. Vessels larger than this would run aground before

reaching the wet basin structures.

9. The quay walls have been designed to accommodate a silt level of

up to 0.0m CD on the northern face of the quay. MDL are to

maintain this as a maximum level by periodic dredging.

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1.5.4 General Main Features

1. The Stage 2 structural wall for the East Quay (North) comprises

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reinforced concrete pier structures at 7.5m spacing along the

inside face of the mass concrete wall.

2. The Stage 2 concrete works on the North Quay consist of the deck

slab and the services gallery along the basin side of the wall.

3. The Stage 2 structural wall for the South Quay comprises

reinforced concrete buttress structures at 7.5m spacing along the

inside face of the mass concrete wall. The buttresses are 1.7m

wide and 5.35m deep. There is a gap of 1.75m between the face

of the mass concrete wall and the inside face of the piers. The

services gallery on the basin side is included in the Stage 2

concrete works.

4. The West Quay (South) and East Quay (South) have no Stage 2

structural walls although the construction of the pump houses,

valve and winch chamber and main deck will form part of the

Stage 2 construction.

5. The West Quay (South) will be constructed “in the wet”, together

with West Quay North A and the Closure Wall. West Quay North B

and C will be constructed in the dry.

6. The pumphouse structure will be constructed “in the dry”, as part

of the stage 2 reinforced concrete works.

1.5.5 Deck Fittings

See Section 1.6

1.5.6 North Quay

1. The width of the North Quay deck structures is 10m.

2. The North Quay wall is designed to accommodate a range of

vessels but with the assumption that it will be used primarily for submarines berthed on submarine launch barges (SLB).

3. The deck loading over the services gallery is 2.5tonnes/m2 (normal

quay loading).

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1.5.7 South Quay

1. The width of the South Quay deck structures is 16.5m.

The South Quay wall is designed to accommodate a range of

vessels but with the assumption that it will be used primarily for

frigates and other surface vessels.

2. MDL have now confirmed that the southern side of the quay will not be used for berthing.

3. The deck loading over the services gallery is 2.5tonnes/m2 (normal

quay loading).

4. An underground electrical switchroom is located at the east end of

the South Quay

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1.5.8 East Quay

1. The width of the East Quay (North) and East Quay (South) deck

structures is 14m.

2. The East Quay wall is designed to accommodate only small

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vessels. Small boat access stairs landing will be provided for this

purpose. See section 1.7

3. East Quay (South) houses the gate winch chamber, the

pumphouse and the valve chamber. All the chambers are located within the body of the East Quay (South) wall.

1.5.9 West Quay

1. The West Quay is in four distinct sections: West Quay (South)

which is to the south of the South Quay, outside the basin; West

Quay (North-A), West Quay (North-B) and West Quay (North-C)

which are within the basin between the South Quay and the

submarine dry dock roundhead.

2. The width of the West Quay deck structures is generally 12m.

3. The West Quay walls are designed to accommodate only small

vessels. Two sets of small boat access stairs within the basin and one set outside the basin are provided for this purpose.

4. The West Quay forms the interface between the Wet Basin

contract and the land side contracts.

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1.6 Deck Fittings and Features

1.6.1 General

A schedule of the deck fittings and features is included in Appendix G.

1.6.2 Fenders

MDL have specified that the fenders for the wet basin shall be arch

type fenders. This type of fender results in relatively high hull contact

pressures. Therefore, in order to prevent damage to the thin hulls of

frigates during berthing, the berthing velocities must be kept low by

very careful berthing operations.

The fender sizes have therefore been chosen based on the normal

berthing of merchant vessels or SLB’s.

The proposed Fenders are as follows:

1. North Quay, North side (sea side)

Due to the limit on protrusion from the quay face, the fenders will

be 500mm deep arch fenders (e.g. Bridgestone SM500H). These

are mounted vertically at 7.5m centres and horizontally in between

at 7.5m centres in a single line at the top of the wall.

2. North Quay, South side (basin side)

Fenders will be arch fenders (e.g. Bridgestone SM600H) mounted

vertically at 7.5m centres.

3. South Quay, North side (basin side)

Fenders will be arch fenders (e.g. Bridgestone SM600H) mounted

at the ends of the buttresses at 7.5m centres. The fenders will extend from +4.55m CD to +1.85m CD.

4. South Quay, South side (sea side)

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9002

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Fenders will be arch fenders (e.g. Bridgestone SM500H). These

are mounted vertically at 7.5m centres. Due to the tidal range the

fenders will extend down to +1m CD.

5. West Quay and East Quay (basin side) Fenders will be arch fenders (e.g. Bridgestone SM400H).

6. West Quay South

Fenders will be arch fenders. (e.g. Bridgestone SM500H).

7. East Quay (sea side)


8. East Quay (Basin side)


9. Lead-in jetty

Fenders will be a combination of cone fenders (e.g. Fentek SCN

900 / 1100) with front panels mounted on each of the dolphin

structures. Horizontally mounted “D” fenders, 500mm deep, will be

provided around the cone fenders, covering the front chamfered

faces of the dolphins. The fenders shall be mounted at

approximately 1.5m vertical centres. The outermost dolphin shall

have similar fenders fixed to the eastern face of the concrete

structure. The main cone fenders will be designed for an abnormal

berthing velocity of 0.5m/s.

10. Entrance - Horizontally mounted arch fenders (e.g. Bridgestone

SM500H). Vertically mounted arch fenders (e.g. Bridgestone

SM600H) will be mounted on the chamfered faces of the entrance

structure.

11. All fenders shall be fixed to the concrete structures with proprietary

marine grade stainless steel fixings. Generally threaded sockets

shall be cast into / fixed into the concrete.

1.6.3 Capstans

1. 10 tonne capstans are provided for assisting the handling of

vessels. 10 No. capstans are provided around the wet basin and

lead-in jetty at locations shown on the drawings. The capstans are

electric driven with the horizontally mounted motors recessed

below deck level.

2. MDL have a preference for a capstan that stands approximately

1.0m high, with a drum height of approximately 0.65m. The motor

and gearbox should be located in a covered pit next to the capstan

such that maintenance of the motor can be undertaken without

removing the capstan drum. A footbrake is to be provided via an

umbilical control.

3. The capstan brake shall remain activated when not in use.

4. Capstans are to operate in both directions with 2 - 3 speed levels.

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1.6.4 Bollards

1. 40 tonne capacity bollards are provided at a spacing of generally

22.5m along the edges of the wet basin, except for the south side

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of the South Quay where the spacing is increased to 30m. MDL

have requested cast iron type bollards.

2. Three 40 tonne capacity bollards are to be provided on the West

Quay (South) as indicated on the drawings.

3. Similar 40 tonne cast iron bollards will be provided on each of the

lead-in jetty dolphins.

4. A single 100 tonne bollard is provided for the purpose of engine

testing and is located at the east end of the South Quay. This

bollard type is embedded steel tubular, filled with concrete and

with solid steel crossbars. The edge of the quay adjacent to this

bollard shall be rounded to prevent damage to the test ropes.

1.6.5 Cable Access Slots

In a central location along the South Quay, two cable access slots will

be provided to allow cables from portable equipment to pass beneath

the crane rails and into the service gallery. The slots shall be 300mm

high and 1000mm wide. The two slots shall be 2.0m between the

centres. The entry to the slot on top of the quay shall be covered with

a suitable galvanised cover, set flush with the deck and be capable of

carrying the quay loading.

1.6.6 Handrailing

1. Handrailing is generally not provided around the edge of the Wet

Basin quay structures. There are no statutory requirements for

such handrails.

2. Handrailing is provided on the walkways between the lead-in jetty

dolphins.

3. Collapsible Handrailing will be provided around the edge of the

small boat access stairs. See section 1.7.

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1.6.7 Deck Drainage

1. The surface of the quay decks have shallow gradient slopes to

facilitate the drainage of rain and other surface water off the quays.

The gradients are generally between 1 in 50 and 1 in 100. Water

will either flow directly off the edge of the quay or will discharge

through drainage gullies spaced at 15m along the length of the

deck.

2. The outer edges of the quay have been detailed with falls away

from the edge of the quay. This is to prevent tools or other

equipment rolling over the edge of the quay. Notches are provided

to allow drainage.

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1.6.8 Overflow Pipes

In order to prevent the water level in the basin rising above the top of

the submarine dry dock gate following heavy rainfall, overflow pipes

are provided through the wet basin walls at 15m spacing. These are

set at with the pipe invert at +5.5m CD which is above highest tide

level but is below the top of the dock gate. The diameter of the pipes

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is 500mm.

1.6.9 Emergency Ladders

Emergency ladders provide a means for persons to escape from the

water after accidentally falling in. Ladders are at 30m spacing along

the edge of the quay walls. The ladders are either recessed into the

wall or have timber protection strips either side of the ladder to protect

the ladder from damage by vessels. Ladders will be fabricated from

galvanised mild steel to enable easy maintenance / replacement by

MDL in the future.

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1.6.10 Tide Gauges

Two timber tide gauges will be provided on the East Quay (South)

near the basin entrance. One will be on the seaward side and the

other on the basin side.

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1.6.11 Transit Marker

A transit marker shall be provided on the East Quay (North) adjacent

to the basin entrance. The marker will consist of an 8m high tower

with a diamond shaped marker at the top. MDL will finalise and

provide the location of the second, land based, marker when the basin

has been completed.

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1.6.12 Office Space

Since on the quay wall no permanent structure can be created, it is

suggested that MDL procure Portacabins of approximately 3m x 12m

dimensions for placement where required. It is further suggested that

these 12No. could be provided along the South Quay and 6No. on the

North Quay. A locked storage space for safe keeping of fittings and

special tools for minor maintenance as required by MDL may also be

provided in one of the Portacabins that MDL would procure / place on

quay walls.

1.6.13 Fire Tender Bays

As discussed in section 1.16.3 below, fire hydrants with a direct

connection to the wet basin are provided along the wet basin South

Quay and North Quay at 15m centres. The deck surface shall be

marked with a hatched area to leave clear for fire tenders at each

location. The bay shall be orientated at 45 degrees to the line of the

quay and shall be 3m wide.

1.7 Small Boat Access Stairs

1.7.1 Re-statement of Function

Small boat access stairs provide an easy and safe means of access to

small boats.

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1.7.2 Location

4 sets of access stairs are provided at the following locations:

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• 2 sets inside the basin at West Quay North B and West Quay

North C.

• 2 sets outside the basin at West Quay South and East Quay

South.

• An access ladder will be provided at the East Quay North where

provision of access stairs is made more awkward by the

suspended deck in this area.

1.7.3 Main Features

1. The sets of stairs inside the basin extend to +2.6m CD

2. The sets of stairs outside the basin extend to +0.9m CD

3. The stairs are recessed into the mass concrete walls of the quays.

4. The stairs are 1.0m wide with a handrail on the wall side of the

stairs. MDL require this handrail to be made from wrought iron for

its corrosion resistant properties.

5. Collapsible handrailing will be provided around the top edge of the

stairs.

6. The steps will be non-slip concrete

7. Mooring rings will be provided for tying up of small vessels.

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1.8 Basin Entrance Works


The entrance works provide the gate abutment, gate quoins, gate sill,

gate apron and commencement to the lead-in jetty.

1.8.2 Main Features

1. The clear width of the entrance between the fendering is 30m.

The width between concrete faces of the abutments is 31m.

2. Horizontal arch fenders are provided on the face of the gate

abutments.

3. Roller fenders are provided at the outer corners of the entrance

structure.

4. Gate jambs and sill are reinforced concrete structures, built as

stage 2 concrete.

5. Quoin stones are pre-cast concrete units with stainless steel face

plates.

6. The level of the sill is -5.0mCD.

7. The sill structure has a silt jetting system connected to one of the

impounding pumps.

8. The sill structure houses the gate bearing castings.

9. The apron structure incorporates the gate rests to support the gate

when it is in the ‘down’ position and reverse load support posts to




November 2003

prevent the bottom of the gate moving under a reverse head.

10. Suitable tide and Basin water level gauges will be installed near

the Basin entrance on the East Quay structures.

1.9 Construction Methods

1.9.1 Temporary Cofferdam

1. The construction of the Stage 2 wet basin walls and the entrance

works will be carried out in the dry. A contractor-designed and

installed temporary cofferdam will be used for this purpose. The

design of the contractors cofferdam will be reviewed by HNBV, but

the responsibility for its adequacy will remain with the contractor.

This remains the case for all the contractors temporary works.

2. The profile of the north gate abutment at the east quay has been

chosen to also form an abutment of the cofferdam.

1.9.2 Construction of Basin Walls Underwater

1. The Stage 1 wet basin walls, which are generally 10m thick

(except on the East Quay South where the walls are 14m thick),

will be constructed by placing concrete underwater within a

controlled environment. The controlled environment may be

created by placing steel shutter box or equivalent, extending from

bed level to above high water level in which silt will be removed

and into which filtered, silt-free seawater will be pumped.

2. The contractor, in the “clean water” environment, can then clean

the founding rock to the satisfaction of the Engineer. It is

envisaged that a combination of air-lifting and water jetting will

enable the contractor to remove any sediments over the rock to a

sufficient degree to achieve a sound foundation for the mass

concrete walls. Proof of the cleanliness of the rock surface will be

proven by the use of underwater video.

3. The concrete will be placed underwater by tremie pipe with shear

keys provided at all horizontal and vertical joints. Each section of

wall will be cast the full width of the Stage 1 wall so that there are

no vertical joints running parallel to the length of the walls.

4. The contract specification will define the requirements of placing

concrete underwater by a tremie pipe.

5. The cleanliness of horizontal “day joints” will also be an important

factor to specify correctly to ensure that any laitence is removed

before fresh concrete is placed on top.

1.10 Wet Basin Gate

Please refer to Section Error! Reference source not found. (Wet Basin Gate Contract)




November 2003

1.11 Impounding Pumps and Housing


The impounding pumps are designed to raise the level of water within

the confines of the Wet Basin to maintain water level control. This

function may be necessary because of water loss by evaporation,

leakage through the Basin walls, leakage past the gate, loss through

underlying rock permeability, or generally after the gate has been

opened and closed following entry or exit of a vessel or vessels.

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1.11.2 Location

The impounding pumps and their electric motors are located within the

Pump House adjacent to the Valve Chamber and Gate Winch

Chamber in the structure of the East Quay (South) wall.

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1.11.3 Main Features

The main features of the impounding pumps are as follows :-

1. 3 (three) No. approximately 600 mm internal diameter self-priming

centrifugal pumps, housed in a dry chamber, with connected inlet

and discharge pipework passing through the walls of the chamber

structure.

2. Each of the three pumps is designed to discharge an average of

4,000 m3 per hour against the varying head conditions. The

pumping system for normal usage is based on two duty pumps

with one standby pump on a rotating duty basis.

3. Each pump is designed to discharge to the Wet Basin through

siphonic discharge to improve pump efficiency and to minimise

accidental pump house flooding risks.

4. The pumps are designed with an intake pipe-culvert of 1.0m

internal diameter and a discharge of approximately 600mm

diameter, tapered expanding over the last 1.5 m to 1.0 m at final

discharge for two pumps. The intake pipe will end in a 90 degree

bend facing downward with a bottom level of +1.0m CD. This pipe

bend may project beyond the face of the wall by up to 1.3m.

5. The third pump is designed to discharge through approximately

600mm diameter pipework, reducing to nozzles located along the

Basin side face of the sill to act as a jetting system for silt disturbance in the gate pit.

6. Each pump may be isolated by means of a gate valve on the

intake side and an engineered stoplog. The stoplogs are housed

within the sea-side walls of the pump house together with

removable trash screens. The screens are removed for

maintenance purposes or installed, in the case of the stoplogs, by

using the Level Luffing crane on the South Quay.

7. The associated electrical switchgear and panels are housed within

a watertight room below the deck of the East Quay (South) wall,

directly beneath the transformer room.

8. The centre-line level of each pump intake is to be defined by the

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physical size of the pump, but it is expected that the top of the

pump volute will be at around +2.0m CD to ensure the pump is self

primed at the minimum pumping level of +2.5m CD.

9. Large reinforced concrete ‘lift-off’ cover slabs set within the deck

permit the complete withdrawal of a pump and associated

equipment for maintenance. The lift-off covers are within reach of

the 100t level luffing crane on the South Quay wall

10. Man access to the pump house is by means of a staircase housing

on the deck, adjacent to the Control Building on the East Quay

(South) wall, and by robust galvanised steel companionway stairs

with safety landings and handrails. An emergency exit is provided

by a ladder located beneath the above ground transformer house

on the quay. Access to this ladder is through the valve chamber.

11. A travelling hoist of 5 tonne capacity will be arranged over the

pumps and motors if required for routine maintenance.

12. The base slab of the pump house will have falls on the floor to

perimeter drain channels, culminating in a small pump sump

suitable for a house pump. The discharge from this pump will be

arranged direct to the Wet Basin.

13. Each siphon will be equipped with a pump-supplier designed ‘fail-

safe’ siphon breaker valve. These breaker valves will be

accommodated in the open on a low raised plinth on the deck

adjacent to the Wet Basin edge.

14. Forced ventilation will be arranged to maintain cooler air through

the pump house and pumps during running periods, with a discharge to atmosphere at deck level.

1.11.4 Electrical Services

Electrical power services to the pump house are as follows :-

1. Power for the pump motors

2. Power for the pump intake gate valves

3. Power for the pump siphon breaker valves

4. Power for controls and instrumentation

5. Power for lighting and emergency lighting

6. Power for small submersible house-pumps when required

7. General power for hand tools and socket outlets

8. Data link cabling to the MDL Yard Control Room if necessary.

MDL to confirm this requirement.

1.11.5 Mechanical and Piped Services

Mechanical and piped services to the pump house are as follows :-

1. Manually operated overhead travelling hoist

2. Compressed air outlet for cleaning purposes

3. Fire hydrants inside and portable fire hose reel system.

4. Hand-held fire extinguishers of appropriate type.

1.12 Equalising Valves and Housing




November 2003


The valve-controlled pipe-culverts, that bypass the gate, are designed

to assist in the control of water levels within the Basin. The use of the

pipe-culverts is only available when the head difference is operating in

the desired direction. The valve type has been selected to operate

equally efficiently for flows into and out of the Basin

1.12.2 Location

The valves and their actuating motors are located within the Valve

Chamber adjacent to the Impounding Pump House in the structure of

the East Quay (South) wall

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The main features of the equalising valves are as follows :-

1. 2 (two) No. 1.2 m internal diameter gate valves housed in a dry

chamber, with connected inlet and discharge pipework passing

through the walls of the chamber structure.

2. Each of the two valves is designed to discharge an average of a

minimum of 4,000 m3 per hour at neap tides

3. Each valve is operated to open/close by electrically powered

actuators mounted directly on top of the valve body, and controlled

either remotely from the Basin-side control room or from within the

valve chamber.

4. Each valve may be isolated by means of two engineered stoplogs,

one on each side of the valve. The stoplogs are housed within the

walls of the valve chamber. A removable trash screen is to be

provided on the seaward side of the valves.

5. The associated electrical switchgear and panels are housed within

a watertight room below the deck of the East Quay (South) wall,

directly beneath the transformer room.

6. The centre line level of each of the pipe-culverts is set at +2.0m

CD.

7. Large reinforced concrete ‘lift-off’ cover slabs set within the deck

permit the complete withdrawal of a valve and associated

equipment for maintenance. The lift-off covers are within reach of

the 100t level luffing crane on the South Quay wall

8. Man access to the valve chamber is by means of an adjacent

staircase housing on the deck of the East Quay (South) wall, and

by robust vertical galvanised steel ladders with safety hoops.

9. A travelling hoist will be arranged over the valves and actuators of

5tonne capacity.

10. The base slab of the valve chamber will have falls on the floor to

perimeter drain channels, culminating in a small pump sump

suitable for a house pump. The discharge from this pump will be

arranged direct to the Wet Basin.

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1.12.4 Electrical Services

Electrical power supplies to the valve chamber are as follows :- 1. Power for the valve actuators

2. Power for controls and instrumentation




November 2003

3. Power for lighting and emergency lighting

4. Power for small submersible house-pumps when required

5. General power for hand tools and socket outlets

6. Data link cabling to the MDL Yard Control Room if necessary.

1.12.5 Mechanical and Piped Services

Mechanical and piped services to the valve chamber are as follows :-

1. Manually operated overhead travelling hoist

2. Compressed air outlet for cleaning purposes

3. Fire hydrants inside and portable fire hose reel system.

4. Hand-held fire extinguishers of appropriate type.

1.13 Cranes

Please refer to Sections Error! Reference source not found. and

Error! Reference source not found. (100t and 15t Level Luffing

crane Contracts)

1.14 Lead-in Jetty


A lead-in jetty provides assistance to the entry/exit of the Basin,

particularly with currents and wind on the broadside of vessels.

1.14.2 Location

The lead-in jetty is located on the north side of the basin entrance and

is orientated such that it is perpendicular to the east quay.

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1. The lead-in jetty comprises three mass concrete dolphins,

approximately 15 x 15 m and spaced at 30m centres.

2. The total length of the lead-in jetty is 96m measured from the face

of the East Quay.

3. Access between the dolphins is by means of steel or reinforced

concrete pedestrian access walkways. For operational reasons,

handrails will be provided only on the north side of the walkways.

The walkways will be 2.0m wide.

4. Each dolphin has a 40 tonne bollard

5. The outer dolphin has a 10 tonne capstan

6. As well as general lighting, the dolphins will have navigation lights.

1.15 Electrical Services




November 2003


Electrical services for the Wet Basin comprise the following:

1. Power supplies to DSU’s 2. Power supplies to cranes

3. Power supplies to plantrooms.

4. Power supplies to capstans

5. Lighting

6. Telecommunication cabling.

7. Data cabling.

1.15.2 Wet Basin Substations

1. The main Wet Basin substation is located at the east end of the

South Quay, designated Substation “C”. The incoming HT supply

will come from Substation A.

2. A second electrical switchroom housing only LT switchgear is

located on the East Quay (north), designated substation “D”. (The

designation of “substation” refers only to the fact that the room

contains electrical equipment).

3. The power supplies to the Wet Basin will be fed primarily from

Substation C although DSU power supplies for half the south quay

will be fed from Substation B.

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1.15.3 Wet Basin Dockside Supply Units (DSU’s)

1. DSU’s will be provided at 15m spacing along the basin side of the

North Quay and along the basin side of the South Quay.

2. DSU’s will be located in surface mounted galvanised steel boxes with hinged doors.

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1.15.4 Power Supplies to South Quay DSU’s

The following electrical supplies are provided at DSU’s on the South

Quay:

1. 415V 50Hz 3 phase supply at 100A. Maximum total power for this

supply is 1000 kVA.

2. 230V 50Hz single phase supply at 30A. Maximum total power for

this supply is 200 kVA.

3. 110V 50Hz 3 phase supply at 100A. Maximum total power for this

supply is 300 kVA.

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1.15.5 Power Supplies to North Quay DSU’s

The following electrical supplies are provided at DSU’s on the North

Quay:

1. 415V 50Hz 3 phase supply at 400A with 63 Amp, 12 way DB.

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November 2003

2. 115V 50Hz 3 phase supply at 63A.

3. 115V 60Hz 3 phase supply at 200A.

4. To be provided at one location at the intersection of the East and

the North Quay:

• 415V 3 phase 50Hz 1250A MCCB with cable termination box

for outgoing cables. (These supplies are required for

submarine battery charging. The battery charging operation

will be carried out for one submarine at a time. The battery

charging duration is 24 to 30 hours. The frequency of battery

charging is once a month).

5. To be provided at two locations along the quay, within larger

DSU's:

• 415V 3 phase 50Hz 300 Amps.

• 220V DC 300 Amps.

1.15.6 Lighting

1. Four high masts located near the corners of the basin will provide

lighting for the wet basin. The masts will be approximately 30m

high lattice masts.

2. Lighting of the lead-in dolphins will be located on lighting poles at

the rear of the dolphins.

3. Strip lighting will be mounted on the lead-in dolphin walkways.

4. The general illumination level for the basin will be 50 lux.

5. The general illumination level for the lead-in jetty dolphins will be

100 lux.

6. The general illumination level of the plant rooms will be 200 lux.

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1.15.7 Power Supplies to Plantrooms

The following plantroom power supplies are provided:

1. Pump house for impounding pumps – see Section 1.11.4

2. Valve chamber - see Section 1.12.4

3. Gate winch chamber

4. Substations and control room

1.15.8 Telecommunications Cabling

Cables will be provided to connect the Wet Basin plantrooms to the

main telecommunications network. MDL are to confirm this

requirement.

1.15.9 Data Cabling

Cables will be provided to send data from the Wet Basin plantrooms to

the main control room. MDL are to confirm this requirement.

1.16 Mechanical Services





November 2003

Mechanical services for the Wet Basin comprise the following:

1. Sea water (fire fighting) system

2. Fresh water

3. Compressed air

4. Oxygen as cutting gas

5. Acetylene as cutting gas

1.16.2 Location of Pipework

The piped services for the Wet Basin will be routed in the services

recesses at the top of the quay walls on the North and South Quay

walls.

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1.16.3 Sea Water System

1. The seawater system will provide take-off hydrant connections at

15m spacing along the basin sides of the North Quay and the

South Quay.

2. The nominal pressure will be 8 kg/cm2.

3. In addition to the hydrants, and stand-pipes with hydrant

connection shall be provided to allow a fire tender to pump directly

from the sea. These shall be at the same locations as the

seawater main hydrants.

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1.16.4 Fresh Water System

The fresh water system will provide take-off hydrant connections at

15m spacing along the basin sides of the North Quay and the South

Quay.

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1.16.5 Compressed Air System

1. The compressed system will provide take-off connections at 15m

spacing along the basin sides of the North Quay and the South

Quay. Three quick release connection points will provided at each

take-off location.

2. The nominal pressure will be 10 kg/cm2.

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1.16.6 Oxygen and Acetylene System

Oxygen and acetylene take-off connections will be provided at 15m

spacing along the basin sides of the North Quay and the South Quay. Quick release connection points will provided at each take-off location.

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------------------------- End of DPR -------------------------

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