A Self-Learning Manual - Institution of Engineers Mauritius

A Self-Learning Manual
Mastering Different Fields of Civil Engineering Works (VC-Q&A Method) Vincent T. H. CHU
found to be more than 10 -2 . However, with the use of 75mm cover, the
corrosion probability is about 10 -3 , which fulfills the Eurocode requirement.
11. What is the design level of landings in piers?
Landings are designed as resting place for passengers during berthing and
deberthing of vessels. In general, landings are provided near mean high
and mean low water levels to facilitate embarking and disembarking of
passengers (BS6349: Part 2: 1988). Therefore, the level of landing steps
should be different from place to place because of different mean high and
mean low water levels in different locations.
12. How does the direction of approaching velocities of ships affect
berthing?
One of the major effects of angle of approaching velocities of ships is its
influence of the energy to be absorbed by the fender system. Consider
several ships berth on the same pier at the same speed but with different
angle of approach, though their kinetic energies are the same, the amount
of energy absorbed by fender differs. The amount of energy absorbed by
fender is [19]:
2 2 2 2
0.
5mv
( k + r cos Φ)
W =
2 2
( k + r )
where W= energy absorbed by the fender
m= mass of the ship
v=velocity of the ship
k= radius of gyration of the ship
r= distance of centre of gravity of the ship to the point of contact of the
fender
Φ=direction of velocity
Hence, when the direction of approaching velocity of a ship is normal to the
fender system (i.e. Φ=90 ), the amount of energy absorbed is smaller
when compared with that of a ship whose velocity is tangential to the
shoreline.
13. What is immersed tube method for underwater crossings?
The immersed tube method for underwater crossing involves the following
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