Issue 2

This colloquium is intended to be an enjoyable experience, with a serious objective. Professor Sir Alan Harris, Mr J. Bobrowski, Professor E. Happold, Professor R. G. Taylor, and Mr C. Hobbs will present the short papers that follow, to initiate a stimulating and provocative informal discussion. A prewar aeroplane hangar structure is described, the roof of which consists of a series of hyperboloids of revolution supported on bowstring girders of 70 m clear span. The thickness of the membrane was 1.4 mm. The authors of the structure had intended that the membrane should be stabilised by tensioning it in a spanwise direction, thereby inducing tension on the membrane in a transverse direction as well. In fact, no advantage was taken of the membrane effect, since the hyperboloids were stiffened by light open-web beams spanning between the bowstring girders. Professor Sir Alan Harris

R. M. Weed (Department of Transportation, State of New Jersey, USA): I am completely in agreement with the author’s efforts to point out that many of the acceptance criteria in existing specifications leave a lot to be desired.

Engineers are either employers or employees. Their rights and corresponding duties arise under the common law and are also embodied in a mass of case law which is the result of interpreting the various statutes. The most important of these is the Employment Protection (Consolidation) Act 1978 which has recently (1980) been amended. This paper considers contracts of employment and looks athe various terms, both express and implied, that constitute such contracts. It also investigates the large and important area of the right of an employee not to be unfairly dismissed. The statutory interpretation of such terms as ‘employee’, 'continuous employment’, 'fixed term contract’, and ‘dismissal’ is examined. Maternity rights, as to pay, time off work, and the right not to be dismissed for pregnancy, are explored, as are other cases where employees can take time off, sometimes with pay. Fair reasons for dismissing an employee, e.g. for dishonesty, are looked at, as are disciplinary and grievance procedures. Finally, there is a brief account of the remedies available for unfair dismissal. Margaret Rutherford

The paper highlights some of the considerations peculiar to extracting energy from a number of alternative sources with particular reference to wave energy and the consequent structural implications. M.V. Woolley and A.H. Tricklebank

Major technological advances in structural engineering that have recently been made, or are in the pipeline, are discussed with indications of how these offer much greater freedom of choice to engineers and to clients in their selection of structures in the future. They also permit more sophisticated designs optimising complex interdependent relationships, as well as a wider range of choice of basic materials and finishes. C. Hobbs

This paper indicates why new materials and new construction techniques are difficult to introduce into the building industry, and draws attention to the fact that loads are more effectively carried by tension than by compression. It concludes that gross deformation structures are bound to be developed in the future. Professor E. Happold

It is postulated that there will be, in the future, an increasing pressure on structural engineers to take always the widest view possible. Designs should be created harmoniously, not merely to resist various actions in the best way but also to ensure quality of execution by taking sociological changes into account. Jan Bobrowski

The use of steel has been greatly influenced by the requirements for fire protection, design standards, and manufacturing processes. Concrete casing could be replaced by water filled fire protection of main columns. The departure from traditional RC construction would permit bigger modular plan clearances and lighter demountable construction. The construction of wide spans with either arch or dome construction, and the possibilities of single-layer shell type structures and their potential uses, are considered. R.G. Taylor

Hybrid structures We have received a letter signed jointly by Dr. D. D. Matthews, Chairman CSB/39 (concrete Code), and Mr B. A. Haseltine, Chairman CSB/33 (masonry Code): The January, February, May, June, and September 1980 issues of The Structural Engineer contained a running debate on the subject of the restraint of loadbearing masonry walls by precast concrete floors and the implications for the robustness of hybrid structures. We realise, from the correspondence to Verulam and from questions raised at other meetings, that this is a subject that is bothering many members of our profession. We thought, therefore, that it would be helpful if we gave our joint views on the subject. Verulam