In this combined experimental and theoretical study the observed sequence of cracking in flat slabs is described and its effect on the distribution of moments examined. A modvied equivalent frame method for flat slabs which is simpler to use than the ACI approach has been developed. The moments predicted by the frame method are compared with other frame analyses and with the results of model tests. A.E. Long and D.J. Cleland
Mr J. M. Mawditt (M): The paper is to be commended for simplifying the design procedure associated with the use of the material stress -strain curves as required by clause 3.3.5.1. of CP 110.
Mr J. A. Waller (F) (Oscar Faber & Partners): I would like to congratulate the authors on a very interesting and thought-provoking paper. In many buildings today, considerable efforts are made to achieve the optimum or lowest cost solution within each professional discipline. Unfortunately, the process is not so often carried out when it involves crossing professional boundaries. The authors have clearly shown what can be achieved if the will is there to try.
Mr T. N. Akroyd (Vice-president): Dr. Lewsley has touched on a matter that has been exercising the minds of many engineers for some time, i.e. professional negligence. I hope, however, that we do not become too morbid over the subject. There is a world of difference between showing a lively interest and a morbid interest because the audience here tonight is composed mainly of ‘doers’ or performers. As doers, if you have a morbid interest in this subject you will stop ‘doing’ and that will be the end of your raison d’etre. There is a world of difference between ‘doers’ and ‘advisers’ because advisers like a situation that is ossified, so that the facts do not change; they can then venture an opinion, 3 months later, on what you should have done at the time, if you had had the benefit of their advice. So there is a problem for the entrepreneur, a problem for the structural engineer, and a problem for the contractor. You have to act now; that usually means you need a clear grasp of the principles involved if you are to act rationally. Christopher Lewsley
President’s diary The President and Mrs Horne look forward to joining members of the Yorkshire Branch at their Annual Dinner and Dance on Friday 8 May 1981. Professor Horne will be taking the Chair at the Institution’s 1-day symposium in London on Tuesday 12 May, when the contents of the draft Code of Practice for low-rise housing will be reviewed.
The nature of engineering judgment and the manner in which it is exercised are considered in the context of structural engineering. J.S. Armitage
Padstones in blockwork Last month we had a query from Mr Cockerill regarding the stress that may be allowed under beams bearing onto blockwork. We have an answer to that query from Mr. B. A. Haseltine, thereby giving you the impression that we write this column only a few days before publication. (Actually, of course, we asked Mr. Haseltine for his opinion!) I would not want your column to become solely a means of getting rulings on the words used in Codes of Practice, but I thought I might comment on the query from Mr Cockerill in the April issue. Mr Cockerill fears that, as Codes become more complicated and lengthy, there will be problems unless everything is spelt out exactly; however, when one looks into his question, the words are quite clear! Verulam