RAILWAY, HARBOUR AND TUNNEL ENGINEERING

Prepared By:-Makwana Ajay136250306028

Berthing Structures-

1. Piers2. Pier head3. Wharf4. Jetty5. Docks6. Mooring Accessories

Piers-The structure which are built

perpendicular to the shore of a sea are known as piers In the sea, the piers are constructed where the sea is not deep and the natural harbour is not convenient for allowing the ships to berth adjacent to the shore. In many cases, the piers are constructed with piles, columns and braces leaving good space for the ocean current to flow without causing any obstruction.

Pier heads-A pier head is at the entrance to a harbour

and as it is expose on three sides, it is subject to more shock than a breakwater.

Wharf-

The landing places or platforms built near shore for vessels to berth are known as wharves. Thus, a wharf affords a working platform alongside the ship in continuity of the shore.

The level of wharf should be above the high water level, but at the same time, it should be economical to load the vessels when the water level is low.

Wharf

Jetties-These are structure in the form of pilled

projections. They are built from the shore to the deep water. They may be constructed in the sea or in a navigable river.

In the sea, jetties are provided where harbour entrance is affected by littoral drift or the sea is shallow for a long distance. The jetties extend from the shore to the deep sea to receive the ship.

Difference between wharf and jetty-A started earlier, a jetty is a piled

projection from shore to deep water to berth vessels along side. Some times a piled projection parallel to the shore is called a wharf.

Thus we may say that a jetty differs from a wharf as follows:

a)The wharf is a berth parallel to the shore, where as a jetty is perpendicular to the shore or break water.

b)The wharf has berth on one side only as it has a back fill of earth. A jetty may have berths on two faces.

Docks

1. Docks are enclosed areas for berthing the ships to keep them afloat at a uniform level to facilitate loading and unloading cargo.

2. A marine structure for berthing of vessels for loading and unloading cargo and passengers.

3. Necessary for discharging of the cargo 4. As ships require a number of days for

discharging cargo, during which period they need a uniform water level.

If ship is subjected to a vertical movement by the tides, great inconvenience will be felt in lifting the cargo from the ship and special arrangement will be needed for lifting the cargo.

Docks can be classified into following two categories:

Wet docks. Dry docks.

Wet docks-

• Docks required for berthing of ships or vessels to facilitate the loading and unloading of passengers and cargo are called wet docks.

• These are also known as harbor docks.

Dry docks

• The docks used for repairs of ships are known as dry docks.

• It is long excavated chamber, having side walls, a semi circular end wall and a floor.

• The open end of the chamber is provided with a gate and acts as the entrance to the dock.

Different Mooring Accessories-

Following are the accessories for a fixed type mooring-

1. Mooring Port-For bringing the ship in to the dock, corner

mooring ports are provided they are attached to the corners of a pier or at the ends of a wharf.

2. Bollard-These are the thick posts designed to take

up pulls up to 35 tonnes or 350KN. They may be provided either by single bit or double bit.

3. Caspton- It is an apparatus consisting of an up right

cylinder around which cables are wound either by hand or machinery. These are helpful when the rope lines to be handled are long and large.

Open Chock

Closed Chock