Issue 12

It must be appreciated that Building Regulations are part of a legal code, and the Public Health Act of 1936 augmented by the Public Health Act of 1961 contain the enabling and enforcing powers, scope and requirements as to approvals or rejections of proposals. F.D. Entwisle

Dr. Goode's paper gives some very interesting data on long-term torsional effects in reinforced concrete and particularly illustrates how 'torsion shedding' can occur in continuous structures. The comparison of strengths with those calculated from CP110 raises two points. Dr. R.A. Swann

I find this paper particularly interesting because my firm were recently engaged by a company manufacturing precast prestressed concrete components to carry out a design study of the behaviour of their strip-type (66 mm deep section) lintels in composite action with brickwork, with the intention of preparing safe load tables and design charts. Our problem was essentially a special case of reinforced brickwork with the embedded bar reinforcement replaced by a prestressed concrete section able to sustain some tension at service loads. After studying the literature, we decided to make an allowance for the effect of the shear arm ratio which is vindicated by the authors' results. R.C. Hairsine

Mr. A. M. Muir Wood (Sir William Halcrow B Partners): I think I am possibly the only one here who has been concerned with each stage of this project from its rebirth, as it were, in 1959 until the date of its suspended animation in 1975. While I have been concerned with it on and off-mostly off-nevertheless, I have seen a number of changes and constant evolution.

The opening section of the clause on design in the Code of Practice for concrete reads: 'The purpose of design is the achievement of acceptable probabilities that the structure being designed will not become unfit for the use for which it is required.. . ' The clause goes on to refer to variations in loading and in the properties of materials used; it mentions the need for statistical data on these variations and introduces the partial safety factors necessary to achieve this design objective. It does not, however, define the acceptable probability of a structure becoming unfit for use which is basic to the design concept. At present this is not possible in quantitative terms and may never become so; it can however be stated qualitatively after appraisal whether individual structural failures or cases of unserviceability are acceptable or not. Experience shows that structural inadequacy is seldom due to a single cause; it is often the result of a combination of effects, which may include overloading, fire, impact or explosion, settlement, design errors and faults in construction. Of these, faults in construction have played a major contributory part in causing failure, as illustrated by a few examples drawn from the building field:

A social involvement The title of my address, 'The structural engineer's significance', is not only provocative, as intended, but is clearly incomplete and poses the obvious question: significant in what respect? To answer the question there are a number of expressions which come to mind: with regard to society; to engineering (and it would be interesting to know what would be the order of preference given these two by most members of this Institution); to the sciences: to the quality of life; to the economy? And there are a number of others. If indeed, we should vary the title by calling it 'The structural engineer's contribution', to the foregoing rather general areas of interest we can add more specific ones, for example: the multidisciplinary team; his own and other professional bodies and institutions; the cityscape. (I have had to coin this word because I could not find one that conveyed what I meant- 'seascape' and 'landscape' are clear enough to everyone but how else could one say, in a word, that one meant the visual impact of the large built-up area?). Peter Mason

As a result of an international architectural competition a Conference Centre and Hotel was designed and built in Riyadh. It was the intention that they should set new standards of building in a country which had previously been almost totally closed to the West. This paper gives the story of the design and construction of this building and describes the types and standards of construction which were achieved. E. Happold, W.I. Liddell and P.A. Woodward

Mr. J. A. Baird has written in amplification of his earlier letter which appeared in this column in September 1975: Somehow my edited contribution on training and engineer's failures has been misunderstood (The Structural Engineer, Vol. 53, No. 9, p. 400). Mistakes are being made and of course they have to be investigated, preferably by someone experienced, perhaps even specializing full time in such work. However, my communication was to draw attention to the appointment made necessary because we, as a profession, are making sufficient errors for a fulltime inspector to be required, and to ask if we are satisfied with current training which has led to this situation. Verulam