Deep beams under top and bottom loading - Reinforced Concrete Deep Beams - page 144

Figure 6.6 Final crack patterns a. W4-L2 ( r v =0) at 140 kN, soffit loading only; b. W1-L2
( r v =1.06%), soffit loading only; c. W3-L2 ( r v =1.4%), soffit loading only; d. W1-L5 ( r v =1.06%), 1:2
top and soffit loading; e.W1-L3 ( r v =1.06%), 1:1 top and soffit loading; f. W1-L4 ( r v =1.06%), 2:1
top and soffit loading; g. W1-L1 ( r v =1.06%), top loading only.
6.6 Crack widths
Cracks are commonly regarded as a cause for concern by engineers because of
the possibility of corrosion of the reinforcement. For serviceability purposes
BS8110 limits the crack width to 0.3 mm for members exposed to an aggressive
environment. The Comité Européen du Béton (CEB) (1970) has similar
proposals, in which the crack width is restricted to 0.1 mm for aggressive
environments, 0.2 mm for normal external conditions and 0.3 mm for normal