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With regard to &19-21 of the Paper, I think that the Author has been over-zealous in his attack on the characteristic strength definitions. Without losing oneself in semantics, the definitions may become more palatable to the Author if the word 'expected' is treated as a technical term which denotes that one is making a statistical statement (i.e. a statement about a population of results that is exactly true in theory only). 55.With regard to the CP 110 compliance criteria and the possibility of a 'logical impasse' ( §30), I think that the Author has hit on a very real practical disadvantage-when it occurs-but according to the statistical philosophy of concrete strength the probability of occurrence of the 'impasse' is small (but non-zero). In other words, the philosophy accommodates an 'impasse' but predicts that it should not happen very often; hence on these grounds it is not deemed important (rightly or wrongly!).56. To put the 'logical impasse' in greater statistical perspective (a) each individual result-x-is required to be such that x > 0.85 k (where k denotes the characteristic strength). Since, by definition, only 5% of results are expected to be less than k, the probability of x 0.85 k (i.e.area A, in Fig. 2) is less than 0.05. In fact it is given by 0.

to verify and develop Beal's graphical method of buckling analysis con®rms that Beal's method is accurate and eective, giving results which agree well with experimental data. The method provides a powerful analytical tool, allowing fast determination of the column capacity for a wide range of slenderness and loading conditions. It is used here to investigate the behaviour of normal-and high-strength concrete columns under both axial and eccentric loads and with a variety of slenderness ratios and reinforcement proportions. The results of this accurate analysis are used as a benchmark for the assessment of code of practice design rules. Existing BS 8110 design rules are found to give poor agreement with both the theoretical analysis and experimental results. New design rules which give more consistent and accurate results are proposed.

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