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
there is no major difference in bond compared with uncoated bars.
16. What is the purpose of skin reinforcement for deep beams?
In BS8110, it states that secondary reinforcement should be provided for
beams exceeding 750mm deep at a distance measured 2/3 depth from the
tension face. Experimental works revealed that at or close to mid-depth of
deep beams, the maximum width of cracks arising from flexure may be
about two to three times larger than the width of the same crack at the level
of surface where the crack originally forms.
The presence of crack is undesirable from aesthetic point of view.
Moreover, it poses potential corrosion problems to reinforcement of deep
beams. To safeguard against these crack formation, skin reinforcement is
designed on the sides of deep beams to limit the formation of flexural crack
widths. Though the principal function of skin reinforcement is to control
crack width, it may be employed for providing bending resistance of the
section.
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