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
design of fender system considers only the largest vessels berthing in the
pier which should be avoided as it might not function for smaller vessels
berthing in dock.
Fig. Effect of smallest vessels in fender design
6. Why is it desirable to select fenders with low reaction force? (FD1)
It is always in the interest of engineers to select fenders with high energy
absorption with low reaction force. The reaction force is an important factor
in the design of quay walls because sufficient savings could be resulted
from low reaction force exerted by fenders. In many fender systems such
as rubber fender, load-spreading panel is often adopted to cater for high
reaction force. Hence, the use of fenders with low reaction force gets rid of
the need of load-spreading panel so that significant economies could be
made.
7. What are the factors determining the stability of a single armour
unit? (A1)
There are mainly three main factors which govern the stability of a armour
unit, namely, gravity, intertangling and squeezing. Obviously, it is beyond
doubt that the ability of the armour unit to stay in place should be closely
related to gravity force. On the other hand, the geometry of the armour unit
also affects its stability. For instance, with the difference in ability to
intertangle, their resistance to pulling out by waves varies. Furthermore,
squeezing forces by gravity also affects the stability of the armour unit
which is dependent on frictional forces in all directions.
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