Issue 12

The author discusses the Ontario bridge Code with its need for only 0.3% reinforcement in each face/direction, compared with three to four times this amount when the slab is designed to BS 5400 with local and global flexure both evaluated and added algebraically. I would concur that the BS 5400 rules for maximum calculated crack width also frequently govern the amount of reinforcement. Indeed, when marine exposure conditions apply, demanding a maximum crack width of only 0.l mm, the reinforcement requirements can be almost impracticable. In this respect, the opportunity to reduce the reinforcement content is welcome. Mr. A.C.G. Hayward

1. Terms of reference The Corporate Plan Task Group commenced work in March 1989. It was formed by the Administration & Finance Committee and was charged with preparing for the consideration of that committee in 1989, and for subsequent submission to Council, a corporate plan for the Institution for the period 1990-1995, having regard to: (i) the development of services to members throughout the world; (ii) the identification of existing and foreseeable external factors impinging or likely to impinge on the Institution and its members; (iii) the implications on the management and resources of the Institution arising from consideration of items (i) and (ii); (iv) the exploitation of the newly-formed service company in the best interests of the Institution and consideration of which of the Institution’s present activities should be transferred to it; (v) the financing of the Institution.

The Building Research Establishment, assisted by Bradshaw, Buckton & Tonge, has studied the report prepared by the Inquiry Commissioner (Dan Closkey) on the failure of the ‘Save on foods’ store in Station Square, Burnaby, British Columbia, Canada. The aim of the work was to determine whether there were any implications from this failure for the recommendations in BS 5950: Part 1. The study has identified some points in the interpretation of the Code which, it is felt, should be highlighted to practising design engineers. D.B. Moore and A.D. Weller

A method is presented for the derivation of structural forms for vaults and sails which are to be designed to carry one dominant load case-dead load in the case of a heavy vault or wind load in the case of a sail. A stress function is used to describe the state of stress in the vault or sail. The stress function is derived from the Biot-Savart law used in electromagnetic theory. C.J.K. Williams

This paper outlines the philosophy and objectives of structural evaluation and describes how the IStructE report Appraisal of existing structures can be used and interpreted to provide a practical basis for decisions concerning the current and future use of buildings for which the original design and construction information is incomplete or unavailable, or where a change of use is envisaged. R.J. Currie

Potential for catastrophe in building alterations The above topic, raised by Peter Mawer in our column for 20 March, attracted numerous responses, published in the journal for 15 May. Predictably, further correspondence has been received. Mr M. J. Foxton, from St. Helens, Merseyside, writes: The situation described by Mr Mawer will be very familiar to anyone engaged in local authority building control in the appraisal of submissions made for compliance with the requirements of the current Building Regulations and Part A of Schedule 1, in paticular. The local authority will, normally, require, in support, the production of such calculations and details as are necessary to demonstrate structural adequacy, including overall stability. Verulam