Verulam

I feel extraordinarily privileged to have been elected as President of Institution of Structural Engineers and to have been given the honour opportunity of addressing my fellow members on a subject that I feel special importance at this stage of our history, namely that of communication. It is important because, although our Institution promotes and, indeed, achieves excellence in structural engineering among its members, I fear we, on the whole, are much less good at communications than others that several of the ills besetting our profession can be attributed to single fact. Professor P.J. Dowling

Over recent years there has been discussion of the possibility of reducing the partial safety factor for reinforcement. This paper puts the case for a reduction from the present value of 1.15 to 1.05. The case is made on three grounds: - 30 years experience with the current safety levels - comparison with structural steel design where lower factors are used - comparison of current sufety level with the recommendations of Eurocode 1. Professor A.W. Beeby

The problem of occupant-induced vibrations in buildings is one of growing importance. Until recently this problem was thought to be confined to floors of timber or composite construction, but in this paper it is shown that some recently constructed concrete floors are sufficiently light and flexible to give rise to disturbing levels of vibration. Methods of designing concrete floors against occupant-induced vibrations are evaluated against an extensive programme of field tests and are found to be deficient in two respects: prediction of the free vibration characteristics of 2-way spanning floors and estimation of structural response to excitations such as walking and heel drop. Martin S. Williams and Peter Waldron