Halifax Building Society New Head Office

Sir, The suggested external emergency escape lifts (Ref. December/l/74) give me concern. Deterioration of cage, mechanism and supports together with failure of the electricity supply persuade me that a chute would be more effective.

Several single-storey model scaffold towers were loaded to collapse to indicate the effects of different bracing arrangements and couplers. They were also analysed for overall elastic instability by means of a modified finite displacements program, which added deflexions to co-ordinates as the loading was increased. No allowances were made for elastic connections or for eccentricity of bracing. The finite displacements method was also used to analyse two three-storey Millshore towers which had previously been tested. Several conclusions are drawn about the effects of different bracings and couplers. The overall elastic instability predictions were found to be within 20 per cent for the model tubular scaffolds and close enough for design, i.e. within about 10 per cent, for the full-scale towers. Failure by lateral-torsional buckling of the second Millshore tower which incorporated open section puncheons was correctly predicted. A design recommendation is made for the effective lengths of scaffold columns. H.S. Harung, E. Lightfoot and D.M. Duggan

After a brief introduction, the reasons are described for setting up LUCID, a joint venture between Loughborough University and over 100 firms in the construction industry, whose aim is to reduce detailing costs. A general discussion of standard details is followed by a description of LUCID standard details and an outline of the overall project development plan. A description of the first, or manual, phase of LUCID to be introduced into design offices is followed by an outline of the possible plans for the future computer phase. Some factors which influence the form of design and detailing systems are then examined and the relationship between LUCID and other systems is described. Development and operating costs are indicated, and the final section estimates the savings in detailing costs that can be expected from the manual phase. L.L. Jones