Discussion on Papers 4 and 5

B. Pritchard, Consulant

One of the points which I should like to make is that, having been brought up to use cracked sections for reinforced concrete, how rarely I see such a cracked section in concrete. A lot of concrete structures seem to be structurally crack free. Most of the surface cracks you see are due to early thermal shrinkage and that occurs in the first few weeks or days of the structure and after that they seem to stay put. It makes you realize that we completely ignore a major feature of concrete, its modulus of rupture, which of course can be quite high.