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The Structural Engineer

Chairman I have a written contribution, from Poul Beckmann, who apologises for not attending his former colleagues’ presentation. First, he would like some further details of the type of lightweight concrete that was used, although of course we have heard a bit more about it tonight than was published in the paper.

The Structural Engineer

Slim-floor construction provides a steel-concrete floor construction of approximately 300mm depth. ‘Slimflor ’ and ‘Slimdek’ construction are trademarks of specific systems of slim-floor construction. This paper reviews the design principles of this form of construction in accordance with Eurocodes 3 and 4, and presents the results of structural and fire tests which have provided data for use in the design process. A key feature is the use of deep decking which spans directly between the beams as a composite slab. R.M. Lawson, H. Bode, J.W.P.M. Brekelmans, P.J. Wright and D.L. Mullett

The Structural Engineer

During 1995 and 1996, a major fire test programme was conducted on a full-scale eight-storey steel-jiramed building. The principle aim of these tests was to investigate the actual behaviour of a steel-framed building subjected to a series of compartment (localised)fires. This paper presents the results from two of these tests, which were conducted by the Building Research Establishment. The results from the tests showed that existing fire Codes are not addressing the correct building behaviour during a fire and, as a consequence, are extremely conservative. In addition, the fire tests on the full-scale frame showed that the actual global and local structural behaviour of buildings is different, and typically far better; than that shown in standard small-scale fire tests. The paper discusses in detail the behaviour of the building observed during the fire tests, and preliminary conclusions are presented. C.G. Bailey, T. Lennon and D.B. Moore

The Structural Engineer

Hipped roofs in timber Various contributions have been received on this topic. Mr L. Wadsworth writes from St John S, Worcester: Having read the anonymous contribution on this subject (16 February 1999), I would like to comment further. I have, in the past, attempted to determine how a hipped roof works, but I used simple statics not 3-dimensional computer analysis. Your contributor says that 'all rafter feet have only z-direction restraint at the wallplate and are hence free to spread'. Presumably, he means that the rafters in the hipped end are supported only in the z-direction since, obviously, all the rafters away from the hipped end will be tied by the ceiling joists.