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
I am very conscious of the great honour that you have accorded me in installing me as President of the Institution of Structural Engineers for the year 79-80. Many distinguished men have preceded me in this office in the 71 years' history of the Institution and, if l cannot match the oratory of some of my recent predecessors, I shall at least try to keep any shortcoming as inconspicuous as possible.
In a previous open discussion at the Institution in January 1977 on the topic 'Towards a European Code for concrete - can concise Codes be compreshensible and comprehensive?', a wide range of opinion was expressed on the requirements for an ideal design Code. Re-reading the discussion leads me to the conclusion that, if as many views as possible are to be accommodated so that the Code can properly claim to be a consensus document, conciseness becomes almost an impossibility.
The elastic critical load of a plane frame is that at which the resistance offered by the frame to any random disturbance is nil. For this state the stiffness matrix corresponding to all possible disturbances is singular. The elements of this matrix are in terms of the physical properties of the members and the modified stability functions tabulated by Livesley and Chandler. The usual method adopted is one of trial and error. A load trial is chosen, the value of the stiffness of the frame is then calculated, and the critical load is that at which the stiffness of the structure vanishes. Several load trials must be made before the critical load is predicted.
S. Z. Al-Sarraf