Author: Porter, D M;Rockey, K C;Evans, H R
First published: N/A
Standard: £9 + VAT
An IStructE account gives you access to a world of knowledge. Create a profile to receive details of our unique range of resources, events and training.
Added to basket
Porter, D M;Rockey, K C;Evans, H R
Queries from several members convince us that there is a prevalent misunderstanding
about written comments on papers published in the Journal; many seem to believe that these are not acceptable, but this is not so. The miscomeption probably stems from the
decision not to give notice of a closing date for written comment as was at one time done for each paper. The reason for this was that quoting a terminal date inhibited and suppressed worthwhile observations, many of which were not formulated in good time and consequently not submitted. Comment which makes a useful contribution is welcome at any time; obviously the sooner after the publication of the paper concerned the better, since it will be fresher in the reader's mind and probably more readily accessible. Nevertheless, good comment is always useful no matter how far removed in time from its stimulus, and it must often be that grounds for comment do not become
apparent until some application reveals a flaw, an inconsistency or, for that matter, a confirmation. Apart from the normal submission of comment to the Editor, there is lways this column in which we will be glad, as we always have been, to air the observations of members, anonymously if they so wish.
Situations are described in which it is advantageous to use composite steel-concrete beams with fewer shear connectors than the number required for full interaction. From a study of the results of tests and computations, simple rules are derived for estimating the ultimate flexural strength of such beams, and for checking deflexions in service, both by calculation and by the use of limiting span-depth ratios.
R.P. Johnson and I.M. May
Structural frames are usually designed to satisfy deflexion requirements by trial and error. Recent optimization methods are restricted to small or very specialized structures. In the general method proposed herein an efficient analysis program is used to determine linear approximations to the rates of change of deflexions with the section properties of the frame members. A simple linear programming procedure then determines the most economical changes of section required to satisfy the deflexion constraints. Cycles of analysis and optimization continue until a satisfactory design is obtained. Comparisons with other methods show that this design is likely to be close to the optimum. Haunched frames can be designed and the reduction in frame stiffness due to compressive axial loads can also be allowed for. Examples of the application of the method to plane steel frames are given.
D. Anderson and J. Salter