coastal engineering-b

Coastal Engineering

Fall Semester

Sept 11 to Jan 12There are two perfectly good men one dead and Sept to Jan

Lecture – 12

CE – 241Transportation Engineering‐1(NIT‐SCEE‐

NUST)

good men, one dead, and the other unbornChinese Proverb

SequenceNavigational Aids

Docks and Port FacilitiesDocks and Port Facilities

– Classification of docks.

– Construction and repair of docksConstruction and repair of docks

Protection, Maintenance and Modernization

Dredging Sluicing and Other related worksDredging, Sluicing and Other related works

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Navigational AidsInclude fixed navigational structure and floating navigational aidsInclude fixed navigational structure and floating navigational aids.

Fixed navigational Structures• Navigational Lights on Piers, Wharves, Dolphins etcNavigational Lights on Piers, Wharves, Dolphins etc

• Light House

• Beacon Lights: include radar reflectors, radio beacons, sonic and visual signals. Visual beacons range from small single‐pile structures to large lighyhouses orbeacons range from small, single‐pile structures to large lighyhouses or light stations and can be located on land or on water. Lighted beacons are called lights; unlighted beacons are called daybeacons.

Floating navigational StructuresFloating navigational StructuresThey are used in waters that are too deep or otherwise unsuitable for 

lighthouse construction 3

Buoy System

Light Ships

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DocksD k i tifi i l l (b i ) idi h lt fDock is an artificial enclosure (basin) providing shelter for berthing of ships. Water in docks may be kept more or less at the same level for ease of operations If it is usedless at the same level for ease of operations. If it is used for loading/ unloading of passengers and cargo, it is known as a Harbour Dock or Wet Dock. If it is used for repairs, it is called Repair Dock or Dry Dock.

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Classification of docksClassification of docks

Harbour Docks (Wet Docks) Why???a bou oc s ( et oc s) y???(1) Tidal range is sufficiently high; more than 5 M.(2) Silting is excessive and draft of entry to dock is reduced.(3) Draft of an old port is to be increased for modern ships.

Rectilinear docks are preferable over curvilinear because of ease of ‘berthing’.ease o be t gWalls are designed as gravity retaining structures and should : 

(1) Withstand backfill pressure when dock is empty.(2) Withstand internal pressure when dock is full with no backfill.(3) Withstand shock when ships contact with dock walls.(4) Withstand concentrated loads of crane foundations bollard(4) Withstand concentrated loads of crane foundations, bollardfixtures for mooring of ships.

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Repair Docks (Dry Docks)Repair Docks (Dry Docks)

• Lift docks :These are platforms, lowered into and raised out from water with 

hydraulic power.

• Slip Docks :Slip Docks :a dock having a sloping floor that extends from deep water to above 

high‐water mark, and upon which is a railway on which runs a cradle carrying the ship.y g p

• Floating Docks :Dock which is made to become buoyant, and, by floating, to lift a 

vessel out of watervessel out of water.

• Graving:dock for holding a ship for graving or cleaning the bottom, etc.

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Comparison of Graving Docks and Floating Docksp g g

(1) Stationery  ‐mobile.(2) Initial cost more(3) Maintenance cost less ‐more.(4) limitation of size ‐ limitation of weight.(4) limitation of size  limitation of weight.(5) major repairs  ‐minor repairs.

Gates are known as caissons These may be sliding withGates are known as caissons. These may be sliding with rollers, rails or keels across the recess.

TRANSIT SHEDS ANDWARE HOUSESTRANSIT SHEDS AND WARE HOUSESDifference ??????

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Dredgingedg g

Protection, Maintenance & Modernization

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Dredging• It is a technique of removing materials from sea bed (or bed of other water• It is a technique of removing materials from sea‐bed (or bed of other water 

bodies) on to the shore. A dredge is a device for scraping or sucking the seabed, used for dredging. A dredger is a ship or boat equipped with a dredge. The terms are sometimes interchanged.are sometimes interchanged.

• Classified as

– Capital Dredging

M i t D d i– Maintenance Dredging

– Improvement Dredging

– Sundry Dredging

CategorizedM h i l D dMechanical Dredgers

Hydraulic Suction DredgersTransportation Engineering‐1(NIT‐SCEE‐

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Types of dredging vessels

• Suction like some vacuum cleaners• Suction like some vacuum cleaners

• A trailing suction hopper dredger (TSHD)

• A cutter suction dredger's (CSD) suction tube has a• A cutter‐suction dredger s (CSD) suction tube has a cutter head at the suction inlet

• Auger suction• Auger suction

• Grab dredging 

• Bucket dredging• Bucket dredgingBed levelerThis is a bar or blade which is pulled over the seabed behind

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pulled over the seabed behind any suitable ship or boat. It has an effect similar to that of a bulldozer on land

SluicingIt i t d f th l h hi• It is resorted for the places near quay where ships are anchored and dredging becomes difficult. Sluicing basins are built which store water during high tides Small holesare built which store water during high tides. Small holes at the bottom are provided. At low tide water is made to rush out thus removing silting.

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DETERIORATION & TREATMENT OF MARINE STRUCTURES

– Wooden Structures

• Decay

T it• Termites

• Wharf Borers

• Marine Borers• Marine Borers

Concrete StructuresConcrete Structures

Steel StructuresSteel Structures

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MODERNIZATION• conventional lift on/lift off (LO/LO) cargo handling facilities many• conventional lift‐on/lift‐off (LO/LO) cargo handling facilities, many 

ports have developed roll‐on/roll‐off (RO/RO) cargo handling.

• Three basic methods are of liftingg

• Loading ramps

Li h b d Shi I hi i l d d l• Lighter‐aboard‐Ship. In this system, cargo is loaded onto large barges called lighters, which are placed aboard a specially designed mother ship for the sea journey.

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ThanksThanks

Any Questions????Any Questions????

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