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The Structural Engineer, Volume 70, Issue 9, 1992
This paper examines the design methods for providing resistance against punching shear, generally concerning the strength requirement for transfer of the load from a flat slab to the supporting column or from a column to its base. The BSI committee B/525/2 (CSB39 as it was then called) had expressed concern about the present design method given in BS 8110: Part 1 : 1985 for providing resistance against punching shear in reinforced concrete slabs. As a result, an examination was carried out, based on a test programme funded jointly by the Department of Environment and the British Cement Association (BCA). The conclusions of this examination have assisted in reviewing the punching shear clauses given in BS 8110: Part 1: 1985*. The results of this exercise have also been used for recommending a revision to the clauses given in the Eurocode 'DD ENV 1992-1-1: 1992 Eurocode 2: Design of Concrete Structures Part I (General rules and rules for buildings)'. This BSI document is expected to be available soon, and it will include a National Application Document providing in formation and additional recommendations necessary for its use in the UK during its prestandard (ENV) stage. P.S. Chana and S.B. Desai
Dr D. Johnson (M) (Nottingham Polytechnic) The author has presented an interesting spreadsheet application in tackling the torsion problem by the stress function formulation, using the finite difference method. While agreeing that such an approach has the attraction of simplicity, it should perhaps be recognised that it also has some limitations. Box and other 'multiply-closed' sections, for instance, are cumbersome to analyse by a stress function formulation and are more conveniently analysed by the use of a warping function. It may also be argued that it is desirable to produce solutions by both warping and stress function based approaches so that upper and lower bounds on the torsional stiffness are obtained, so minimising the need for successively refined analyses. Unfortunately, the warping function approach is much less amenable to finite difference modelling, although either function may be readily used with the finite element method, which would appear to be more versatile in this respect.
The typical German Technische Universitat, formerly called ‘Technische Hochschule’, offers structural engineering as part of its civil engineering course which would also include traffic, hydraulic and environmental engineering. Western Germany has such universities at Aachen, Berlin, Bochum, Braunschweig, Darmstadt, Dortmund, Hannover, Karlsruhe, Munich, and Stuttgart. It is not yet finally decided which schools will become technical universities in the eastern part of Germany, except for Dresden. The formal curriculum, including classes and tutorials, usually covers 9 semesters or 4½ years. However, the average student takes between 5 and 6 years to complete his studies. His university studies will start at an age of 21 since, after finishing at high school, he has to complete 18 months’ military service (or alternative service for conscientious objectors) and some compulsory practical training. J. Schlaich, Professor Dr Ing.