ble to apply controlled lateral loads to actual buildings, these full scale tests are being performed in an experimen- tal five-storey structure built in a dis- used quarry. In this way it is possible to apply simulated wind loads by hydraulic jacks pushing against the rock face.
These tests on complete sections of structure have already resulted in more accurately defined permissible shear stresses for the code of practice. They have also indicated appropriate meth- ods for use in design calculations and the degree of accuracy which may be expected in these calculations.
Although these investigations were embarked upon long before the Ronan Point disaster in London, in 1968, this occurrence and its aftermath have given even greater point to well-found- ed information on the structural be- haviour of multi-storey buildings.
New stringent requirements
The Ronan Point incident, in which four people died when part of a 22-storey block of flats collapsed fol- lowing a gas explosion, has also led to new and stringent requirements for structural strength and stability in Britain's Building Regulations and this
in turn has given rise to the need for accurate information on the resistance of brick walls to lateral pressure and on the stability of structures which have suffered accident damage. Both these problems are being studied at full-scale at the quarry test site.
The results of these tests are en- couraging in that brickwork elements couraging in that brickwork elements have been shown to possess consider ably greater resistance to damage by lateral pressures, as might arise from a gas explosion, than was previously sup- posed. Furthermore, the stability of brickwork structures which have suf- fered accidental damage has been de- monstrated and the reliability of meth- ods of assessing this stability has been put to a practical test.
Tests on complete structures must of course be supported by theoretical studies and detailed laboratory work. Computer methods now make it pos- sible to carry out almost brick-by- brick calculation of stress conditions in walls but these in turn have to be based on laboratory determinations of materials properties and on studies of mechanisms of failure in brickwork elements under various stress condi- tions. Very difficult problems of in- strumentation arise in this work, call
ing for the use of the most advanced strain measuring techniques.
The outcome of this work in general terms will be to contribute to the economy of building, particularly in relation to residential building which is a substantial factor in any country's economy. The benefits will not be limited to high rise construction but will be applicable in all multi-storey work.
For example, greater knowledge and more refined methods of struc- tural design will make it possible to exploit with safety the use of rather weaker materials which have not hitherto been regarded as suitable for serious structural use or, if they have been used, only in an uneconomical way in terms of labour, material and reduction of usable space as a result of great wall thicknesses.
The latter point is of special signi- ficance in developing countries which have an imperative need to use indi- genous materials as effectively as possi- ble. Thus, there are in many countries considerable possibilities for using bricks of only moderate strength which have been overlooked for mod- ern structural purposes in an age of steel and concrete.
Far East BUILDER, January 1971
FITTINGS FOR THE WORLD'S METAL WINDOWS
Smith Wallis manufacture and supply all types of Fittings for metal windows with a complete range of designs in brass, aluminium or steel to suit every requirement. Agents:
S. F. WONG, Box 1232, Hong Kong N. P. KING, Box 79, Singapore Smith Wallis & Co. Ltd. Highgate Road,
Birmingham 12, England.
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