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The Structural Engineer

Professor S. Mackey (F) : My main concern is to learn why, in Britain, limited records of wind and pressure measurements are being extrapolated to such a degree that if applied to Hong Kong conditions would render economic design of buildings impossible.

The Structural Engineer

Mr. B. Rhodes: Mr. Longbottom has done less than justice to large diameter strand, by which I mean 28 mm (1 1/8 in) diameter strand. I know it is not used a lot, but this is really because of lack of effort on the part of the manufacturers and the system suppliers. 28 mm diameter strand has certain basic drawbacks, namely: 1. The shape of the load/extension curve 2. Relaxation losses at 6 per cent 3. Lower grip efficiencies 4. The tendency to fly open when cut 5. The 'banana' effect at the ends

The Structural Engineer

The author's experience on several codes-of-practice committees has led him to the conclusion that one of the greatest fields of uncertainty lies in the specifying of effective lengths of continuous columns. This is coincidental with the difficulty of calculating elastic critical load factors and dealing with frame instability. Comprehensive design charts are given for effective lengths of columns with any local degree of end restraint, both for sway and no sway conditions. To design for the limit-state of collapse it is essential to discover new 'desk' methods of dealing with overall frame instability when effective lengths based on local restraints are not accurate enough. A new technique of 'stiffness distribution', akin to moment distribution, will be acceptable in a drawing office, both for steel and reinforced concrete frames, at the same time providing rapid estimates of the other limit-state of permissible sidesway. Important modifications for strain hardening and composite panel stiffening are included, indicating the urgent need for more full-scale tests on composite action with cladding. The emphasis throughout has been on simplicity of theory and of the many worked examples. R.H. Wood

The Structural Engineer

In recent months Sir Kirby Laing, Sir St. John Elstub and Mr. A. G. Milne, as Presidents respectively of the Institutions of Civil, Mechanical and Electrical Engineers have been considering the future organization of the profession. At the beginning of July Sir Leonard Atkinson, as Chairman of the CEI, invited the presidents of all 15 CEI constituent institutions to consider an analysis of what was seen by the three Presidents as being the current problem. At that meeting it was arranged that the respective Presidents would consult informally with their Council colleagues and return to the matter at the end of September.

The Structural Engineer

On 20 July last, under ref. BRA/1068/2, the DOE addressed the letter given below to local authorities, new town development corporations, etc. The letter contains an assessment of the BRE Report on the failure of roof beams at Sir John Cass's Foundation and Red Coat Church of England Secondary School, Stepney, and sets out a programme of action for inspection and assessment. Attached to the letter was an annex 'Suggestions for testing high alumina cement concrete' which is published on page 326.

The Structural Engineer

As reported in Institution Notes on page 322, the Council recently asked the Secretary of State for Energy to take action to solve a number of difficulties experienced by British engineers working on the design of North Sea installations. The disquiet felt by the Institution was set out in detail in an appendix to a letter to the Minister, the text of which is given below.

The Structural Engineer

Mr. Derek R. R. Dick, BSc, CEng, FIStructE, FICE, will take office as President of the and at an Ordinary Meeting at 11 Upper Institution 1974-75 on 3 October next evening will deliver his Presidential Address Belgrave Street, London at 6.0 pm that 'The Future of the Institution'.

The Structural Engineer

By any standards bomb damage is a messy business. Even when considered by the structural engineer back in his office and away from the debris and the broken glass, it is untidy and presents problems that are far different from those entailed in the design of new works. Peter S. Rhodes