STEEL BUILDINGS

Evening Star, Issue 20312, 22 October 1929, Page 14

STEEL BUILDINGS

HEW RESEARCH SCHEME The Department of Scientific and Industrial Research of Great Britain lias completed arrangements for an important investigation to begin in 'the early autumn into the application of modern theory of structure to the design of steel structures. The investigation is intended to be the most thorough ever indertaken into the problem, and is expected to last several years. Its objective is to secure if possible scientific "esuits v bell may justify a more economical nsi of steel in building cons- - .-notion The suggestion to bold -dm inquiry ivas made bv the British Steelwork -Association. a recently-tinned oigan-f.-a tion, which comprises pranti ai-lly all British fabricating linns aid lOlleis of structural steel, and has for its objective the promotion of new and extended uses oi steel. The association invited the Department of Scientific and Indus-, trial Research to organise a thorough investigation into the problem, and it offered a financial contribute!! of £2,000 per annum for five years, which will cover about a. half of tho estimated costinvolved. Realising the importance of the suggestion, and bearing in mind the success which recently attended tho efforts ot tho Bridge Stress Committee, the department, after consultation with the Institute of Civil Engineers, willingly accepted the task, and has undertaken to hear the other half of the cost. AH AUTHORITATIVE COMMITTEE In order to ensure that tho results of the investigations will command ready acceptance the department has appointed an authoritative committee, composed of representatives of the association, the Institute of Civil Engineers, and nominees of the department, under tho chairmanship of Sir Clement Hindley, with tho following terms of reference : (i.) To review present methods and regulations for tho design of steel structures, including bridges. (ii.) To investigate the application of modern theory of structures to the design of steel structures, including bridges, and to make recommendations for the translation to practice of such of the results as would appear to lead to more efficient and economical design. The Director of Building Research will act as executive officer to tho committee, and tho work will bo carried out partly at the building research station and partly at the universities under the supervision of the professors concerned. For full scale work advantage will bo taken of facilities that can be offered by constituent members of the association. Tho consideration underlying tho .investigation is a recognition that full advantage is not being taken ot the qualities which steel possesses as a material for building construction. This neglect is attributable partly to the lack of more precise _ knowledge of the strength characteristics of steel and of its behaviour under load, and partly to the prevalence in building codes of restrictions, which, nrhaterer their merits in tho early stages of development, have remained too long unrevised. FACTOR OF SAFETY The factor of safety originally adopted was really a factor of ignorance to allow, among other things, for the incomplete stress analysis. The same factor is stil' used in the design of a good deal of steel construction, notwithstand-ing-the advances made in both the quality of the material and general knowledge of structural design. So far as theory of structures is con cerned,’ the important developments as sociated with aircraft design and with tho design of railway bridges'find small

counterpart in general steel construction. There has been little development in the technique of stress calculations in this particular- branch of engineering over a long period. During the last decade the question lias received serious attention in America and Germany, but so far not much has been achieved, and a comprehensive range ot work remains to be done. This is evidenced by the fact that a sub-committee appointd in 1922 by the American Society of Civil Engineers to consider working stresses of structural steel in buildings, and also the possibility of conducting stress measurements on steel structures,-were unable to reach definite conclusions. The time seems opportune for an organised attempt in England to introduce more exact methods of calculation. There is every reason to believe that by refining tho methods of stress calculation it would bo possible to obtain a inncn closer idea of the loads to be provided for in a given structure and to adopt a precise "for lower) factor ot safety. In the first place, a careful examination is called for ot the materials and also of the standard methods ot design considered from the point of view of adequacy of treatment in the light of modern knowledge of theory of structures. In this connection the building regulations of public bodies, it is thought, might with advantage be thoroughly analysed to determine how far they call for unnecessary weight of material. This ' examination would doubtless indicate the need for the consideration of many special problems—for example, the degree of fixing which should be allowed for stanchions under various conditions, and the efficiency ot riveted connections in ensuring a certain amount of continuity to beams, etc. These two instances are quoted merely as illustrations; many other points would certainly arise whose investigation might well load to more efficient and economical uses of stool. ARCHITECT’S VIEWPOINT In a lecture to the Royal Institute of British Architects, Mr Harvey Wiley Corbett discussed tho latest American building methods, and threw some light on tho much-discussed question of the life of a skyscraper. “Steel,” he said, “ has made possible the piling up of stories to great heights. It has made possible extremely rapid construction. Speed and steel are the two most important factors affecting our present American architecture. An additional factor, which is tho result of these two, has been a new conception in regard to the permanency of buildings. “ Buildings in tho past have been erected with tho idea of .lasting indefinitely; they have lasted centuries, as you have them hero in the Old World. But with speed of construction tho idea that a building is necessarily permanent is gradually being replaced by the idea —in America at least—that a building is designed for a specific purpose and for a specific time, and that its life is limited by its usefulness for that purpose. “In our .commercial work wo design buildings to last a matter of twentyfive to thirty years. They are structurally quite as sound as any buildings over erected We do not know what is tho life of steel in terms of centuries, but at least we feel that from the Structural point of view the building is durable. We do not, however, expect it to last from tho practical, serviceable point of view. Wc exp'ect to have that building taken down at the end of twenty-live years and replaced by a new building, which will bettor serve for that particular time.”