Verulam

Large multibin silo complexes can be designed to dimensions, anatomies, and configurations that give optimum economy. Foundation conditions have a marked influence on this. Generally, the best capital and working returns come from silos that have their bins arrayed in plan roughly square, rather than long and narrow. Civil engineering costs are then reduced too, and the facility lends itself to greater flexibility of operation. John Faber and D.J.A. Alsop

The design and construction of the Hopewell Centre in Hong Kong are described. The buildings comprise a 64-storey office block, along with lower carpark and shopping blocks on a site whose levels vary by 48 m. The major design considerations are reviewed. These include the stability of the site after completion of the excavation, an economical structural form for the 216 m-tall block under its loadings, especially wind, and the arrangements for rapid construction of the reinforced concrete frame. Some aspects of the construction are outlined, including the excavation methods for the site formation, the installation of rock anchors, and the slipforming systems for the walls and columns. The concrete foundations formed on the granite rock, the permanent rock drains, and the protection of the adjacent sites, are described. Reference is made to other design factors, such as the temperature effects on the building, the methods of analysing the structural performance of the frame, and the arrays of holes in the core walls. The shopping and carpark blocks are described briefly. Duncan Michael, Thomas K. C. Wan and James Hannon

The time lens Any historical account of a subject is almost certain to put a ‘time lens’ on the immediate past so that it appears to the reader that very little occurred before the start of the present century. So it is with the history of science. And yet at the same time there are sufficient eminent men of earlier years (Newton, Galileo, Archimedes, Euclid, etc.) to give the impression to school children that science has been progressing for at least 1OOO years. One should never forget to add the words, ‘but slowly!’ in reference to anything that occurred before the beginning of the 19th century. Where the time lens really works is when we look at the history of technology, for by inference, in what might be called a traditional sense, technologists pick up the brilliant discoveries of scientists and exploit them for hard cash. E.R. Laithwaite