Correspondence on The Behaviour and Assessment of Multispan Arches by Dr. W.J. Harvey and Dr. F.W.

Papers - too ‘academic’? The comments by Mr Skinner in our column for 21 April, inspired by Professor W. M. Jenkins ’ paper ‘Structural optimisation with the genetic algorithm’, and followed up by contributions from Professor Jenkins himself and Professor A. W. Beeby (16 June), have brought comments from Mr S. B. Tietz on his reactions to the paper. Mr Teitz also responds to our own invitation, to those who have authored ‘practical papers’ to comment on the ‘challenges and satisfactions’ of so doing: The correspondence has caused me to reexamine Professor Jenkins’ original paper of 17 December 1991. My sympathies lie with Mr Skinner! Any paper which brings in genetic algorithms, combinatories, stochastic processes, crossover, mutation and parameter scaling, all within a 16-line synopsis, surely deserves all our admiration if not our comprehension. Seeing what Professor Jenkins can do with the English language I shall eagerly seize on Professor Goldberg’s work on which this paper is apparently based! Verulam

This paper summarises an experimental investigation into the effects of alkali-silica reaction (ASR) on the punching shear strength of reinforced concrete slabs. Tests were carried out on 84 reinforced concrete slabs in which ASR was accelerated in the laboratory. The variables investigated were: the amount of ASR expansion; the amount, location, end anchorage and type of reinforcement; and the external restraint to a slab. It was found that, in general, ASR expansion and cracking did not reduce the punching strength of a slab but did increase its ductility. However, at extremely high ASR free-expansions in excess of about 6000 µstrain, concrete delaminations occurred parallel to the reinforcement planes of doubly reinforced slabs, and this effect reduced the punching shear capacity of such slabs. K.E. Ng and Professor L.A. Clark

For many years, business organisations in the USA have looked for ways both to reduce the amount of litigation that takes place there and to achieve savings in time and money in the procedures involved in litigation. The first objective - to try to reduce the amount of litigation - faces major constitutional problems; however, the second - to try to reduce the length, complexity and cost of litigation - has in some cases been achieved by Alternative Dispute Resolution (ADR) techniques. J.J. Ward