Stress Corrosion Cracking of Stainless Steels in Swimming Pools

Design for wind loading Readers may remember our earlier correspondence arising from the discussion which took place at the Institution following the damage observed to have been done (and not done!) to buildings as a result of the storm of 14 October 1987. During that discussion, it had been commented that, despite the widespread occurrence then of wind speeds corresponding to a return period of 200 years, little or no primary damage had been suffered by ‘engineered structures’. In our issue of 15 March, Mr L. Metter pointed out that many of those structures had been designed using the 1952 Code, using loading less onerous than that introduced into CP3: Chap. V: Part 2: Wind loading in 1972, and from this he drew the conclusion that the wind loading called for in the later Code was ‘both onerous and incorrect’. To this, John Mayne of the Building Research Station responded on 21 June, cautioning against such a conclusion being drawn because of the uncertain division of the global safety factor between loading and the many other uncertainties for which it allowed. We ourselves and a later correspondent (Adrian Warburton on 16 August) remained unconvinced about the lessons to be drawn, and we are pleased that Barry Haseltine now draws our attention to a further assessment in a new report from BRE: Verulam

The use of raft foundations in the UK has led to a general adoption of the type, similar to the example shown in Fig 1. These usually incorporate stiffened 'edge' beams with a total foundation depth of approximately 600mm. This is an ideal solution for highly compressible, frost susceptible soils but, in more favourable soil conditions, a more economic solution might be found. J. O'Rourke and A. Robinson

Most human endeavour entails some degree of risk. Such risk may be commercial, can relate to meeting or failing to meet a programme or performance criteria, or may concern safety considerations, i.e. risks to life or health. S.B. Tietz