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
normally designed to carry loads from metal columns through the ground
surface to the footings which are located below the ground surface. With
the installation of pedestals, it is the pedestals, instead of metals, which
come into contact with soils. The purpose of the provision of pedestals is to
avoid the direct contact of metal columns with soils which may cause
possible metal corrosion by soils. The soils around the pedestals should be
properly compacted to provide sufficient lateral resistance to prevent
buckling of pedestals [9].
Fig. Pedestal
16. Is stainless steel really stainless in construction application? (S9)
Stainless steel refers to alloy steels with more than 10.5% of chromium and
consists of several groups like austenitic, ferritic, martensitic etc. Austenitic
stainless steel is normally used in structural applications because of its
high corrosion resistance. Austenitic and ferritic types of stainless steel
cover about 95% of stainless steel applications. Stainless steel is not
stainless although it is corrosion resistant under a wide range of conditions.
A passive layer of chromium oxide is formed on stainless steel’s surface
which renders it corrosion resistant. This chromium oxide layer acts as a
stiff physical barrier to guard against corrosion and makes it chemically
stable. Moreover, when this layer is damaged, it can perform self repairing
where there is a sufficient supply of oxygen. However, stainless steel will
still corrode by pitting in marine environment where chloride attack occurs.
Therefore, appropriate grades and types of stainless steel have to be
selected in polluted and marine environment to minimize the problem of
corrosion. Reference is made to Euro Inox and the Steel Construction
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