Transcript
HARBOUR AND DOCK
ENGINEERING
Presentation 7Asnidha V, Asst. Prof, CE Dept. Mdit
Asnidha V, Asst. Prof, CE Dept. Mdit
Approach:
– path through which ship can enter the harbour safely.
Approach channel:
When sea around the harbour has depth less than draft
required for the largest ship visiting the harbour a separate
approach demarcated and dredged for required depth is
necessary.
Lock gates:
–When water level of sea around the port is varying to a
large extend
1. On leeward side - safe 2. On windward side
basinbasin
sea sea
Asnidha V, Asst. Prof, CE Dept. Mdit
1. Pointing down
stream3.Pointing upstream
• Not favorable
– Silt deposits
– Requires maintenance
dredging
Harbourbasin
Harbourbasin
Harbourbasin
2.Pointing midstream
• Difficulty in
maneuvering
Asnidha V, Asst. Prof, CE Dept. Mdit
• Depth – draft of largest ship
• Width – widest ship
• Length – type of entrance
• Tidal Entrances
– Entrance without gates
• Impounded Entrances
– Entrance with gates
I. Entrance with one pair of gates
a) Ebb gates
b) Storm gates or flood gates
II. Entrance with two or three pair of gates
1 a.Ebb gates
• Stop flow of water from
harbour during low tides.
• Entry of ship – only during
high water level.
1 b.Storm gates or flood gates
• Stop flow of water into the
harbour during flood
WL. In harbour is above L.W.L harbour
Asnidha V, Asst. Prof, CE Dept. Mdit
2.Entrance with two or three pair of gates
• Water level in lock
chamber can be
altered.
• Entry and exit of
ship takes more
time
seaW.L. =19.85m
Lock chamberW.L.= 18.95 m
harbour basin W.L. = 20.25 m
Asnidha V, Asst. Prof, CE Dept. Mdit
• Lock is a device for raising or lowering boats between stretches
of water.
• It is used to make river more easily navigable or to allow a canal
to take a reasonably direct line across land that is not level
Give access to docks
Consist of chamber, enclosed quay walls on each side
Paved at the bottom by an inverted arch flooring, to resist
upward water pressure, when dock level is low
Locks have two pairs of gates with a lock chamber in
between.
costly
• width varying from 25m and above
• depth 8m to 12m
• length 240m and above
• It may be wooden or iron
• Wooden gates consists of series of horizontal beams of green
heart
• Iron gates consists of plate iron ribs, covered with a skin of
iron sheeting
• Shape
– usually straight or curved
• Curved gate
– is strong against the transverse water pressure
–Curved gates are theoretically the best type
–But curved gates are longer and costlier
Asnidha V, Asst. Prof, CE Dept. Mdit
Support for lock gates
• Gate is fitted with a pivot cap at bottom of heel post
and an encircling anchor strap at the top
• Usually opened and closed, by two sets of chains,
one for opening and other for closing
• Chains are fastened at 1/3rd its height on both sides
• For small boat canal gates, lock gates can be
operated by hand
Asnidha V, Asst. Prof, CE Dept. Mdit
THANK YOU
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