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
Fig. Different types of sheetpiles
10. What are the advantages in using castellated beams? (S5)
Castellated beams refer to the type of beams which involve expanding a
standard rolled steel section in such a way that a predetermined pattern is
cut on section webs and the rolled section is cut into two halves. The two
halves are joined together by welding and the high points of the web
pattern are connected together to form a castellated beam. The castellated
beams were commonly used in Europe in 1950s due to the limited ranges
of the available steel rolled section and the cheap labour cost. In terms of
structural performance, the operation of splitting and expanding the rolled
steel sections helps to increase the section modulus of the beams.
Moreover, it is versatile for its high strength to weight ratio so that lighter
section can be designed with subsequent cost saving in foundation [20].
11. How do corrosion inhibitors function? (S6)
Corrosion inhibitors are chemical substances that, when added in small
concentrations, stop or reduce the corrosion or reaction of the metal with
the environment. It normally functions by one or more of the following
mechanisms [50]:
(i) It may alter the external environmental conditions by taking away or
inactivating an aggressive agent;
(ii) It may adhere to form a film on the surface of the metal;
(iii) It brings about the formation of corrosion products.
12. Why should protection be implemented for steelwork against fire?
(S7)
Owing to the high thermal conductivity of steel, the temperature of
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